Radiance Research AcademyInternational Journal of Current Research and Review2231-21960975-5241921EnglishN0001January1General SciencesLignocellulose Degrading Enzymes from Fungi and Their Industrial Applications
English0112Perinbam KantharajEnglish Bharath BoobalanEnglish Seeni SooriamuthuEnglish Ravikumar ManiEnglishThe rich diversity of fungi and diverse range of enzymes produced by them together make researchers to exploit their potential for various industrial applications. Few of the fungal enzymes have already been harnessed and many other are to be explored and brought into use. Recent studies suggested that the lignin degrading fungi can be used in the bioremediation of aromatic hydrocarbons including dioxins, dibenzofuran, aromatic dyes, etc. Employing fungal enzymes for the treatment of pollutants has gained attraction recent days for their selectivity, specificity and eco-friendly nature. Of these enzymes, peroxidases (lignin peroxidase and manganese peroxidase) and laccases are the two major classes of enzymes involved in biodegradation of lignin and recalcitrant xenobiotics. In addition, cellulase and hemicellulase were found to play a role in the management of lignocellulosic wastes. The present review gives a detailed account on the various lignocelluloses degrading enzymes, their fungal sources and their industrial applications. ± ± ± ±
EnglishPeroxidases, Lignocelluloses degradation, Xenobiotics, Fungal sources, Industrial applicationsINTRODUCTION
Lignocelluloses are the main structural component of all plants and most of the industries including forestry, agriculture, food, pulp and paper are producing large amount of lignocellulosic wastes1-4. Most of the agricultural residues are rich in non-edible lignocelluloses and serve as renewable sources for the production of various value added products including biofuel which can act as the replacement for the fossil fuels5. Alternative fuels of petroleum solve many of the current social problems and concerns, from air pollution and global warming to other environmental improvements and sustainability issues6 In order to exploit the uses of lignocellulosic biomass, several physical and chemical processes have been developed for the separation of cellulose, hemicellulose, and lignin from them. The separation processes include chemical viz. alkali, acid, ammonia and lime and microwave pre-treatments (physical)7. The commercial pre-treatment process carries respective drawbacks including decrease in the quality of the polymers, release of by-products that inhibit the fermentation of resulting sugars, etc.
In order to overcome these drawbacks, biocatalysts (enzymes) can be used to improve the superiority of the pretreatment process8,9. In turn, enzymes produced by wood decaying fungi serve as an important factor for the conversion of organic debris into humus and helps in the carbon and nitrogen cycling. The lignocellulytic activity of the fungi is also facilitated with the help of extracellular enzymes, such as cellulases, hemicellulases, MnP (Manganese peroxidase), LiP (Lignin Peroxidase) and Lac (Laccase). These enzymes can be used in the management of environmental pollutants such as textile effluents, pulp effluents, organochloride agrochemicals and crude oil residues10,11. The filamentous fungi are rich in the production of extracellular lignocellulolytic enzymes, when compared to bacteria and yeast12. Since, today's world demand for more constant, active and specific enzymes, wood decaying fungi serve as an ideal candidate for the management of lignocellulosic wastes. In order to exploit the uses of lignocellulosic biomass, enzymes produced by wood decaying fungi can be used as an important factor for the conversion of organic debris into humus and helps in production of value added products. Even though many fungal species are involved in the biodegradation of pollutants including xenobiotics, it is essential to investigate their sources, diversity and mode of action. The present review will aid to acquire knowledge of different lignocellulosic enzymes, the fungal strains responsible for their production and their industrial applications.
Plant cell wall
Plant cell wall is a multifaceted composite of polysaccharides, aromatic compounds, proteins, etc. The plant cell wall consists of three important lingocellulosic components which include cellulose, hemicelluloses and lignin. In a plant, the lingo-cellulose materials comprise 30-50% of cellulose, 15-30% hemicelluloses and 15-35% of non-carbohydrate aromatic polymers the composition vary based on the species, morphology and age of the plant13,14. The secondary cell wall is synthesized and differentiated by cellulose microfibrils with superior crystallinity and altered hemi-cellulose content15. The large quantity of lingo-cellulosic materials present in cell wall make them the abundantly present, potentially inexpensive and easily available natural resources for the production of biofuels and high value compounds16. The use of lignocellulosic materials primarily involves the separation of the polymeric compounds into cellulose and hemicelluloses. In the absence of potential enzymes, the natural degradation of such lignocelluloses is very slow: however, microorganisms in the soil are capable to degrading the compounds and converting them into sugars at faster rate. Microorganisms capable of growing on lignocellulosic materials produce a wide range of enzymes that could be of scientific and industrial importance. Moreover, the alcohols produced by the utilization of ligocellulosic wastes could be utilized as a biofuel. Also, chemicals like vanillin, xylitol, and furfural obtained from lingocellulosic wastes can be used in industrial products including herbicides, pharmaceuticals, and household products17,18.
Wood decaying fungi
The omnipresent fungi are the extensive producers of hydrolyzing enzymes which are responsible for the degradation of carbohydrate present in dead plant biomass19,20. Generally, fungi require favorable temperatures (32o - 90o F), nutrients and sufficient source of oxygen for them to survive and multiply. Since forests represent the major biome of the earth, fungi inhabiting the forests are able to degrade and mineralize the major chunk of ligno-cellulosic substrates. Fungi can be differentiated into different classes based on their distinct spore structures including Ascomycetes, Basidiomycetes and Deuteromycetes21. The wood decaying fungi use both enzymatic and non-enzymatic system for the degradation and complete decomposition of wood. In the wood decay process, wood turns discolored and loses weight, strength and density by the action of fungi. Most of the fungi involved in degradation of lignin and hemicelluloses fall into three broader groups namely, brown-rot, white-rot and soft-rot fungi22.
Brown-rot fungi
The brown-rot fungi generally reduce the strength of wood upto 75% by decomposing the cell wall polymers such as cellulose and hemicellulose leaving behind the lignin23. Brown rot fungi make the wood fragile, dry and crumble into cubes due to the formation of longitudinal and transverse cracks24. The brown rot fungi dry out, makes wood into to powder when crushed and it is characterized by reddish brown color and dry, crumbly and brittle consistency . Brown rot is often referred as "dry rot". Poria incrassate is one of the water conducting brown rot fungi having specific rhizomorphs based on root-like water-conducting tubes to transport water from the soil to the wood and can be decayed by the fungus. Once the brown rot fungus infected, it can rapidly multiply from side to side building and destroying large areas of floor covering and walls in one or two years. Examples of such wood decaying brown-rot fungi include Gloeophyllum trabeum, Fomitopsis lilacino-gilva, Laetiporus portentosus, Postia placenta and Serpula lacrymans24,25. In contrast, the numerous enzymes secreted by brown-rot and white-rot fungi enhance the wood degradation26.
White-rot fungi
White-rot fungi belong to the family, Basidiomycetes which gradually utilize all major cell wall components such as carbohydrates, lignin and aromatic compounds27,28. Ceriporiopsis subvermispora and Phlebia radiata are the two best studied white rot fungi to elicit white-rot decay29,30. The white rot fungi produce three classes of extracellular ligninolytic enzymes: laccase, lignin peroxidase and manganese peroxidase that produce H2O2 needed for peroxidase activities. The white rot fungi Rigidoporous lignosus is known to produce two oxidative enzymes such as MnP and laccase which is capable breaking down the lignin in a synergistic system31. The mixed cultures of white-rot fungi are also found to improve laccase production32. Dichornitus sqiualenis appeared to delignify early wood cells, whereas, Phellinuis pini delignifies latewood cells effectively. Otjen33 observed decay patterns in oak caused by Inonotits diyophillis which demonstrated that the fungus has a preference of early wood fibers and parenchyma cells but not latewood fibers.
Soft rot fungi
Soft rot fungi otherwise referred to as micro fungi were characterized by cavity formation in the secondary walls of the wood cells34. Generally, soft rot fungi utilize cellulose and hemicellulose. Soft rot fungi degrade wood at slower rate compared to brown rot fungi and white rot fungi. In general they are found in wet floor boards, rotting window frames and fence posts. Some of these fungi are common decomposers of cellulose in soil and they are the least specialized wood decaying fungi.
Enzymes involved in lignocellulose degradation
Laccases and peroxidases are major lignolytic enzymes involved in enzymatic lignin degradation35,13. In addition, cellulose, hemicellulase and pectinase also play role in lignocellulosic waste degradation. Particular significance is attached to fungi producing the lignocellulosic enzymes (Table. 1) and their role in the process will be discussed.
Cellulases
Cellulase hydrolyses the glycoside bond present between the glucose residues in the organic polymer cellulose (Fig.1). Cellulose can be hydrolyzed by β-1,4-endoglucanases, exoglucanases or 1,4-β-cellobiosidase, and β-glucosidase 36-38. Immanuel39reported cellulase production by Aspergillus niger and Aspergillus fumigates and optimized the parameters including pH, inoculums size, temperature, presence of inducers, etc. Trichoderma reesei is identified as the efficient cellulase producer by many researchers to degrade the cellulose40-42. Elyas43 and Dubrovskaya44 have isolated β-glycosidase enzyme from marine derived fungi such as Aspergillus sp. and Penicillum canescens. The amount of β-glucosidase in the Trichoderma cellulase system is reported to be lower than that needed for the efficient saccharification of lingocelluloses45. In a recent study, the cellulose produced by the Aspergillus sp. was used for the enzymatic saccharification of lignocellulosic agrowaste7. In addition, the production of cellulase has been widely studied in P. chrysosporium, Sclerotium rolfsii, Aspergillus sp., Penicillium sp., Schizophyllum sp. and Trichoderma sp.46-48.
Hemicellulase
Hemicellulase such as xylanase are hydrolyses the xylan(Fig. 2) are extensively studied and applied on industrial scale with higher pulp brightness resulting in a lower chemical input49. In a recent study, a cold active xylanase was isolated from a marine fungus, Cladosporium sp50. In addition, the xylanase and endo-xylanase production has been widely studied in fungi such as Penicillium thomii51, P. pinophilum52,53, A. niger54and Ceratocystis paradoxa55. From an industrial point of view, an alkaline xylanase producing fungi, A. niger56and P. canescens57were isolated from marine sources.
Pectinase
The pectinolytic enzymes are produced by both plants and microorganisms. In plants, the pectinases are concerned with fruit ripening and softening whereas, pectinase produced by microorganisms helps in the degradation of the dead vegetable biomass for their utilization in soil fertilizer and nutrient recycling58,59. The pecinases degrade the pectins (Fig. 3) via depolymerization and de-esterification reactions60. Pectinase production has been studied in the following group of microscopic fungal species: Aspergillus, Penicillium, Colletotrichum, Sclerotina, Fusarium, Trichoderma, Verticulum, Sclerotium, Geotrichum61-66. Among them A. niger was found to be a good producer of commercial67,68. Many industrial firms are involved in the commercial production of pectinases used in protoplast isolation whose purity and activity vary from one source to another. Pectinase production has also been studied in phytopathogenic Ascomycetes including, Neurospora crassa, Thermoascus aurantiacus, Rhizoctonia sp69,70 yeast like Saccharomyces cerevisiae71and Zygomycetes such as Mucour sp. and Rhizopus sp.72,73.
Lignin Peroxidase
Lignin peroxidases are the heme glycoprotein that plays a vital role in lignin degradation (Fig. 4), which cleaves C-C bonds and oxidizes benzyl alcohols to aldehydes or ketones74,75. Lignin peroxidases act on both phenolic (e.g. syringic acid, guaiacol, catechol, vanillyl alcohol, acteosyringone) and non-phenolic lignin substrates25. Mostly, basidiomycetes are shown to produce efficient lignin peroxidases76,25. Extracellular lignolytic enzymes are prominently produced by P. chrysosporium and P. radiata77whereas Coriolus tersicolor, are capable of producing intracellular lignolytic enzymes78. Researchers have studied the lignin peoxidase producing ability of different fungi including P. chrysosporium79, T. versicolor80, Pleurotus ostreatus81, Panus sp., P. coccineus, Perenniporia medullapanis, and P. sanguineus82.
Manganese peroxidase
Manganese peroxidase degrades the lignin mainly by attacking phenolic lignin component83. In the presence of H2O2, manganese peroxidase oxidizes the phenolic structures by converting Mn2+ to Mn3+. Oxalate and malonate are the mediators that produce carbon centered radicals, peroxyl radicals and superoxide radicals which improves the effective lignin-degrading system83,25. Manganese peroxidase is an essential component to certain basidiomycetes and some wood decaying white-rot fungi, which secrete manganese peroxidase in several forms into their environment. Among the basidiomycetes, Agaricus bisporus84, Lenzites betulinus85, Panus tigrinus86and Nematoloma frowardii87are identified to produce more stable manganese peroxidases. Järvinen88 have studied MnP production on selected lignin degrading organisms P. chrysosporium, Physisporinus rivulosus, P. radiata and Bjerkandera sp. and found P. chrysosporium as best manganese peroxidase producer. Bonugli santos89 isolated marine fungi, Mucor racemosus which possess the ability to produce salt tolerant manganese peroxidase.
Laccase
Laccases are the copper containing polyphenol oxidases which enable degradation of phenolic compounds and also reduce molecular oxygen to water (Fig. 5)90-92. Laccases oxidize the phenolic units in lignin to phenoxy radicals, which can lead to aryl-C cleavage93. Laccase can also oxidize non-phenolic substrates in the presence of certain auxiliary substrates94. A large variety of fungal strains isolated from several sea grasses, algae and decaying wood samples possess the ability to produce laccase enzyme. Atalla95 have isolated Trematosphaeria mangrovei from mangrove ecosystem which produces laccase enzyme at significant quantity. A thermo stable, metal-tolerant laccase is reportedly produced by marine-derived fungi, Cerrena unicolor96. Various researchers have isolated laccase producing fungi from different sources including Trichoderma harzianum97, Trichoderma atroviride98 and Trichoderma longibrachiatum99, Trametes versicolor100, Lentinus tigrinus101, Trametes pubescens102, Cyathus bulleri103, Paecilomyces sp.104, P. chrysosporium105, Lentines edodes106 and Pleurotus ostreatus107,81, Ganoderma lucidum91, Alternaria tenuissima108 and Trichoderma sp.92.
Applications of lignocellulytic enzymes
Lignocellulytic enzymes are industrially very useful and the fungal cellulases are having emerging applications in various industries like fruit juice processing, ruminant nutrition for improving digestibility and de-inking of paper109,110. A cellulase produced by Aspergillus sp. was used as refining aid for cotton comber pulp, and was changed into value added security paper111. The cellulase obtained from fungal sources also plays a key role in the preparation of household detergents and are also used in textile industry for bio-polishing of fabrics, stonewashing of denims112. The cellulase is also used in the animal feeds for increasing the nutritional quality, to develop digestibility113-115. Fungal hemicellulases are used in the production of chemical pulps and improving pulp beat ability of unbleached pulps116-117.
Fungal pectinases are being used in other industries such as textiles, plant fiber processing, tea, coffee, oil extraction, treatment of industrial wastewater, paper making, etc.119-120. Among the fungal sources, A. niger produces commercial pectinases which are used in the fruit juice and wine making industries. Pectinase accounts for 7.5% in the global enzyme market costing approximately 75 million USD72. The major applications of the pectinase enzymes are found in vegetable and fruit processing, where the removal of undesired pectin during extraction and clarification of fruit juice, wine, and cider is carried out.
There is an enormous interest in wood decaying fungi for large scale biodegradation applications due to their ability to produce large amount of extracellular lignocellulolytic enzymes28. Mtui and Masalu121 have isolated a lignocellulolytic fungus, Laetiporus sulphureus, from mangrove forest having the ability to degrade cellulose, hemicellulose and lignin presented in the mangrove litter. Immobilized enzymes are employed in the pharmaceutical, food and chemical industries 122. Immobilization also facilitates the efficient recovery and reuse of costly enzymes, and enables their use in continuous, fixed-bed operation123. The enzyme produced by the fungi was also employed for the detoxification of aromatic pollutants like agrochemicals and industrial effluents. The lignolytic white rot fungi have found their potential applications in the fields such as decolorization of industrial dyes, bleaching of pulp from textiles and paper, and degradation of organo pollutants, etc.28,124. The salt tolerant lignin degrading enzymes from fungi can be used for the effective bioremediation of environment pollutants125. The MnP finds their major applications in biomechanical pulping, dye decolorization, biorefineries, bioremediation and pulp bleaching 126,127. In modern sensitive studies involving plant protoplast fusion and gene transfer processes, purified cellulases and pectinasers find immense use and Japanese are the pioneers in this field.
Sahadevan128 reported lignin-degrading enzymes, LiP, MnP and Laccase from MVI.2011 an alkalophilic fungus to afford an appropriate biological substitute to treat highly alkaline effluents like pulp, paper industry and waste water. Indira Priyadarsini129described that the ability of fungi to produce laccase was linked with the effective decolorization of azo dyes which can be exploited for the screening of laccase producers. The fungal laccases are widely used in the industries such as food, textile, wood processing, pharmaceutical and chemical industries. In recent years, laccases are widely studied for textile industry in denim bleaching130,131. Another important application of laccase is the bioremediation of poisonous organic pollutants like chlorophenols and polycyclic aromatic hydrocarbons from the soil132,133. The stable laccase enzyme produced by A. tenuissima is being used in several bioprocesses, such as biopulping, biobleaching, bioremediation, food technological uses, and treatment of industrial waste water134-136.
Conclusion
Among the three groups Ascomycetes, Basidiomycetes and Deuteromycetes organisms producing lignocellulosic enzymes, Basidiomycetes group of fungi are considered as the promising candidates for the degradation lignocellulosic biomass. Even though many fungal species are involved in the biodegradation of pollutants, it is essential to augment the reactions by the development of new strains and employing microbial consortium or enzymatic cocktails for industrial applications. The enzyme production by the filamentous fungi are having biotechnological importance due to their applications in different fields including plant protoplast culture and protoplast fusion. The typical ecosystems present a veritable emporium of such organisms which are as yen poorly understood and commercially less exploited. When compared to cellulose and hemi-cellulose, lignin is found to be most difficult to degrade. For the hydrolysis of lignin, in addition to physical and chemical elements, addition of enzyme will be effective in terms of economic use as well as eco-friendly and sustainable use. The present review will aid to acquire knowledge of different lignocellulosic enzymes, the fungal strains responsible for their production and their industrial applications. Further studies are necessary to investigate the industrial applications of these enzymes for emerging production and innovation of new fungal strains.± ± ± ± ± ±
Acknowledgment
Authors also acknowledge the immense help received from the scholars whose articles are cited and included in refeences of this manuscript. The authors are also grateful to authors/ editors/ publishers of all the articles, journals and books from where the literature for this article has been reviewed and discussed.
Conflict of interest
There is no conflict of interest.
Table 1: List of fungi producing lingo-cellulolytic enzymes
ORGANISM
ENZYME PRODUCED
REFERENCES
A. niger, A. fumigates
Cellulase
Immanuel et al.39
T. reesei
Cellulase
Stricker et al.40; Kubicek et al.42
Aspergillus sp.
Cellulase
Elyas et al.43
P. canescens
Cellulase
Dubrovskaya et al.44
Aspergillus sp.
Cellulase
Bhavsar et al.7
P. chrysosporium
Cellulase
Saratale et al.48
Trichoderma viride
Cellulase
Iqbal et al.146
Cladosporium sp.
Xylanase
Del-Cid et al.50
P. thomii
Xylanase
Palaniswamy et al.51
P. pinophilum
Xylanase
Li et al.52; Lee et al.53
A. niger
Xylanase
Sharma et al. 54
C. paradoxa
Xylanase
Dekker and Richards55
A. niger
Xylanase
Raghukumar et al.56
P. canescens
Xylanase
Burtseva et al.57
A. niger
Pectinase
Sakai et al.58; Martens and Schaap68
N. crassa
Pectinase
Marcus et al.69
T. aurantiacus
Pectinase
Rombouts and Pilnik63
Rhizoctonia sp.
Pectinase
Martins et al.70
S.cerevisiae
Pectinase
Poondlaet al.71
Mucour sp.
Pectinase
Kashyap et al. 72
Rhizopus sp.
Pectinase
Kolarova and Augustin73
P. radiate
Lignin peroxidases
Lee et al.77
C. tersicolor
Lignin peroxidases
Lobarzewski 78
Schizophyllum commune
Lignin peroxidases
Asgher et al.137
P. chrysosporium
Lignin peroxidases
Zeng et al.138; Junnarkar et al.139
T. versicolor
Lignin peroxidases
Johansson et al.80; Asgher et al.140
P. ostreatus
Lignin peroxidases
Sivakami et al.81
P. sanguineus
Lignin peroxidases
Pointing et al.82
A. bisporus
Manganese peroxidase
Lankinen et al.84
L. betulinus
Manganese peroxidase
Hoshino et al.85
T. suaveolens
Manganese peroxidase
Knezevic et al.141
P. tigrinus
Manganese peroxidase
Lisov et al.86
Trametes villosa
Manganese peroxidase
Silva et al.142
N. frowardii
Manganese peroxidase
Hilden et al.87
P. chrysosporium
Manganese peroxidase
Järvinen et al.88
P. rivulosus
Manganese peroxidase
Hakala et al.143
P. radiate
Manganese peroxidase
Hilden et al.144
Bjerkandera sp.
Manganese peroxidase
Järvinen et al.88
M. racemosus
Manganese peroxidase
Bonugli santos89
T. mangrovei
Laccase
Atalla, et al.95
C.unicolor
Laccase
D'Souza-Ticlo et al.96
T. harzianum
Laccase
Holker et al.98
T. atroviride
Laccase
Velazques et al.99
T. longibrachiatum
Laccase
Kiiskinen et al.10
T. versicolor
Laccase
Han et al.100; Asgher et al.154
L. tigrinus
Laccase
Ferraroni et al.101
T. pubescens
Laccase
Shleev et al.102
C. bulleri
Laccase
Salony et al.103
Paecilomyces sp.
Laccase
Liang et al.104
P. chrysosporium
Laccase
Viswanath et al.105
L. edodes
Laccase
Shanmugam et al.106
P. ostreatus
Laccase
Patel et al.107; Sivakami et al.81
G. lucidum
Laccase
Li et al.91
T. suaveolens
Laccase
Knezevic et al.141
A. tenuissima
Laccase
Abd El Aty et al.108
Trichoderma sp.
Laccase
Divya et al.92
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Radiance Research AcademyInternational Journal of Current Research and Review2231-21960975-5241921EnglishN-0001November30General SciencesUsing Activities in Teaching: A Study of Central Tibetan Schools Administration (CTSA) Teachers in India
English1318Pratima KumariEnglishIntroduction: With the use of activities in classroom, a teacher can motivate students to learn theory, enhance learners’ ability to recognize multiple perspectives, develop critical thinking and help in retention and application of activity.
Materials and Methods: This paper is based on the feedback given by the 22 Post Graduate Teachers (PGTs) regarding activity-based teaching at Higher Secondary Stage in different subject areas from four states during a 10 Day In- Service Programme at NCERT. To assess the usability of activities, a feedback form was administered to teachers. The questions were both quantitative and qualitative. Focus group discussion with the teachers was held so that their true feelings may be recorded.
Results: 97 per cent teachers responded that activity based method was better than lecture for retention and application of activity. Activities illustrate the practical application of theories and, most important, the relation between theories and practical results. 85 per cent teachers were of the opinion that the use of activities will enhance students’ ability to recognize multiple perspectives.
Conclusion: The findings of the study have ascertained and supported to the activity based method for better application/teaching. The classroom discussion that activities stimulate is highly rewarding. The use of activities is able to change the classroom environment from the passive listening of lectures and writing notes into the exchange of ideas. The evidence from the study suggests that the use of activities does more than stimulate academic discussion. The teachers take more interest and are motivated to teach the subject with the activities. They feel that the use of activities are interesting and adding interest to the subject and makes the classroom more real.
EnglishCritical thinking, Inquiry, Discussion, Multiple views
INTRODUCTION
Active engagement involves enquiry, exploration, questioning, debates, application and reflection, leading to theory building and the creation of ideas/positions. Schools must provide opportunities to question, enquire debate, reflect, and arrive at concepts or create new ideas. An element of challenge is critical for the process of active engagement and learning various concepts, skills and positions through the process (NCF 2005). One video on 'Auctioning out Event' activity for Economics subject was shown to the teachers and they were motivated to use this activity in the classroom for teaching-learning during the training programme. The teachers actively watched the video. Majority of the teachers were of the view that teaching through activities will be able to infuse critical thinking and inquiry among the students as they provide at one side opportunities for active participation in the discussion and questioning and in turn improving their communication skills and on other side they help in bringing out the multiple.
Perspectives on the various topics like economic systems, poverty, rural development, and organic farming etc. in developing the nature of inquiry and critical thinking. Research shows that traditional lecture based method, where the students sit passively and a teacher talks has dominated in school education till date. 'Having the instructor provide all the materials to the passive student is the old paradigm. The new paradigm is to actively engage students with the material and one another'.1 'Engaging students in learning is one of the many goals that educators face.' 2 The rationale for using this methodology is that it helps students remember and apply abstract concepts; it is successful with students of different ability levels; it promotes social growth as well as economic understanding; and because it is fun, students are more interested in the subject matter. 3 An activity provides a very nice change of pace. As with anything, the constant use of activities would become trite, but well timed, well placed activities can provide a nice spark to class, and make the classroom a more enjoyable place for both students and the professor. 4 There is a need to move away from the traditional chalk and talk to more child centred pedagogy, which means "giving primacy to children's experiences, their voices, and their active participation. This kind of pedagogy requires us to plan learning in keeping with children's psychological development and interests.5" Economics is taught by teacher-centred activities in schools of India that emphasizes the memorization of facts and concepts. She also noted that using activity definitely increases the engagement, participation, retention and development of skills like problem solving and critical thinking in students. 6, 7, 8, 9, 10, 11 The typical characteristics of active learners are- they ask questions for clarification, challenge ideas procedures and content, connect current learning to past learning, attach what is learned with skill development, discuss what is known with others and remain enthusiastic about learning.12 Through guidance students learn to understand the perspectives of others, without always believing that there is only one view. Students question the own actions in the activity which helps them understand principles and reach conclusions. Classroom environment becomes co-operative and collaborative rather than individualistic and competitive.13
Need for the study
The present study looks into when students do not understand the purpose of learning theory in subjects like Economics, the process is more dry and difficult than it needs to be, and they often fail to grasp the tools they need. Activities are well suited and better than lecture, for addressing this issue which is discussed in this paper. The school is the only platform to motivate the learners especially first generation learners and from economically weaker sections of rural areas whose parents are not literate and learners stay more at home compared to school and there is no guidance at home. Simply telling learners that they will get good marks if they write the same things learnt through lecture method/guide book is not an effective motivator. Learners get opportunity to share their thoughts in class freely in activity based method. The available researches in the area established the fact that the activities enhance learners' ability to recognize multiple perspectives, develop critical thinking and are helpful for retention and application of activity.
Research questions
Do activities motivate the learners to learn theory and seek the required information?
Does the use of activities enhance learners' ability to recognize multiple perspectives?
Do activities develop critical thinking among the students?
Are activities helpful for retention and application of activity?
Objectives of the study
To know that the activities are able to motivate the learners to learn theory and seek the required information.
To know the use of activities and impact for enhancing learners' ability to recognize multiple perspectives in teaching learning process.
To know the activities develop critical thinking among the students.
To know the learning with activities is useful for retention and application of activity.
Hypothesis
The activities motivate the learners to learn theory.
The activities enhance learners ' ability to recognize multiple perspectives.
The activities develop critical thinking among the students.
Learning with activities is useful for retention and application of activity.
MATERIALS AND METHODS
Methodology
To achieve the objectives of the study, the session is designed in two parts. In Part I, video on the
Activity 'Auctioning out Event' was shown to teachers. In Part II, their feedback was obtained.
Target group
22 Post Graduate Teachers (PGTs) of Central Tibetan Schools Administration (CTSA) of Economics, Commerce, History, Geography, Mathematics, Biology, Physics, English and Tibetan Language were taken for the study.
Selection of states
The teachers play an important role in improving the quality of teaching learning process directly and the teacher educators indirectly. Until the teachers are exposed to the innovative pedagogies like use of activities in teaching learning, they are not be able to transact in the class in the same spirit. Therefore, the Post Graduate Teachers of Economics, Geography, History, Commerce, Biology, Physics, English and Tibetan language are needed to get enrich about innovative teaching methods to teach at higher secondary stage to make teaching learning process more engaging, participatory and effective. A sample of 22 Post Graduate Teachers of these subjects from four states i.e. Uttrakhand, Karnataka, Himachal Pradesh and West Bengal was selected for the study.
Development of tools
The present study involves the use of the following tools: To assess the usability of activities, a feedback form was administered to teachers. The questions were both quantitative and qualitative. Focus group discussion with the teachers was held so that their true feelings may be recorded.
RESULTS
The results of my endeavour were as under:
Question 1: Do you think this activity is fruitful for qualitative teaching and develop critical thinking among the students?
Table1: Reported fruitfulness of the activity for qualitative teaching by teachers
Responses (number of teachers)
F
M
T
(i)
Yes, this activity is fruitful for qualitative teaching because it will motivate the students to take part in discussion and activities which will develop their questioning skills leading to critical thinking skills, knowledge and experience regarding economic and social issues. It is based on the real situations.
01
18
19
(ii)
Yes, because through this, students could understand the social issues of our society and how much these issues were related to their daily life.
01
02
03
Total
02
20
22
Question 2: How does the activity reflect the concerns and perspectives of National Curriculum Framework 2005?
Table 2: Responses of teachers regarding reflection of the concerns and perspectives of National Curriculum Framework 2005 by this activity
Responses (number of teachers)
F
M
T
(i)
Yes. Because through this activity we can or student can understand the various economic and social issues and it will improve their all round development.
02
17
19
(ii)
Yes. The objective of real education and the way of implementation, the code and conduct etc were dealt very seriously.
00
03
03
Total
02
20
22
Question 3: How does this activity reflect the concerns and perspectives of National Curriculum Framework for Teacher Education 2009?
Table 3: Responses of teachers regarding reflection of the concerns and perspectives of National Curriculum Framework for Teacher Education (NCFTE) 2009 by this activity
Responses (number of teachers)
F
M
T
(i)
Yes. Activity will fulfill the aims and objectives of NCFTE 2009 i.e. knowledge based on understanding and application.
02
15
17
(ii)
Yes. NCFTE 2009 objective is to impart the basic idea among students. It is successfully achieved by the activities.
00
05
05
Total
02
20
22
Question 4: Would you recommend this method to other Economics teachers? Yes / No All teachers said yes.
Question 5: What constructive criticism you would like to offer to the resource person to improve the quality of activity? Give details.
All the teachers said that even though the activity based method was very effective, still more time should have been given for the detailed discussion and presentation. It will be effective if all are involved effectively.
Question 6: Activity was used for demonstration. Kindly rate this activity in terms of its objective, presentation and coverage of issues.
Table 4: Rating of activity in terms of objective, presentation and coverage of issues by teachers
Responses (number of teachers)
F
M
T
(i)
Not Satisfactory
0
0
0
(ii)
Below Average
0
0
0
(iii)
Average
0
01
01
(iv)
Good
01
15
16
(v)
Excellent
01
04
05
Total
02
20
22
Question 7: How does the activity help you to make informed decisions in organizing your Economics classes?
Table 5: Rating of the activity in terms of making informed decisions in organizing Economics classes by teachers
Responses (number of teachers)
F
M
T
(i)
Not Satisfactory
0
0
0
(ii)
Below Average
0
0
0
(iii)
Average
0
0
0
(iv)
Good
01
18
19
(v)
Excellent
01
02
03
Total
02
20
22
Question 8: Do you think that this activity "auctioning out event" will be able to increase the knowledge, application, presentation, analysis and overall personality of each and every student? If yes, why?
Table 6: Teachers responses regarding usefulness of "auctioning out event" for increasing the knowledge, application, presentation, analysis and overall personality of each and every student
Responses (number of teachers)
F
M
T
(i)
Yes, it gives the idea of a topic from different perspectives, all the learners get chance to clarify the doubts and also to give their opinion about the concept.
01
18
19
(ii)
Yes, it will increase the knowledge, application, presentation, analysis and overall personality development each and every learner by interaction, basic problems of students are solved, and it is easy to maintain each and every student's profile.
01
01
02
(iii)
Yes,
Confidence will boost up.
Participation in any activity of the school will be increased.
All around development increases.
0
01
01
Total
02
20
22
DISCUSSION
Teachers were unequivocal in their perception that the use of this activity had contributed to their learning. The study reveals that 86 per cent teachers responded that this activity is fruitful for qualitative teaching because it will motivate the students to take part in discussion and will develop their knowledge and experience regarding economic and social issues. It is based on the real situations. 14 per cent teachers responded that this activity is fruitful for qualitative teaching because through this, students could understand the social issues of our society and how much these issues were related to their daily life (Table 1). 100 per cent teachers responded that activity is fruitful for qualitative teaching. 86 percent teachers thought that activity reflects the concerns and perspectives of National Curriculum Framework 2005 because through activity we can or students can understand the various economic and social issues and it will improve their all-round development. 14 per cent teachers thought that activity reflect the concerns and perspectives of National Curriculum Framework 2005 because through activity, the objective of real education and the way of implementation, the code and conduct etc. were dealt very seriously (Table2).
18 per cent male teachers were of the view that activity reflects the concerns and perspectives of National Curriculum Framework 2005 because through activity, the objective of real education and the way of implementation, the code and conduct etc. were dealt very seriously. 100 per cent female teachers thought that activity reflects the concerns and perspectives of National Curriculum Framework 2005 because through activity, we can or students can understand the various economic and social issues and it will improve their all-round development.77 percent teachers thought that activity reflects the concerns and perspectives of National Curriculum Framework for Teacher Education 2009 because will fulfill the aims and objectives of NCFTE 2009 i.e. knowledge based on understanding and application. 23 per cent teachers thought that activity reflects the concerns and perspectives of NCFTE 2009 because NCFTE 2009 objective is to impart the basic idea among students. It is successfully achieved by the activity based method (Table 3). 100 per cent female teachers thought that activity reflects the concerns and perspectives of National Curriculum Framework 2005 because through activity we can or students can understand the various economic and social issues and it will improve their all-round development. 100 percent teachers said that they will recommend this method to other Economics teachers. 100 percent teachers said that even though the activity was very effective, still more time should have been given for the detailed discussion and presentation. It will be effective if all are involved effectively. 72 percent teachers assessed that the use of activity is "good" in terms of objective, presentation and coverage of issues. 5 percent teachers assessed "average" in terms of objective, presentation and coverage of issues. 23 percent teachers assessed "excellent" in terms of objective, presentation and coverage of issues. 50 per cent female teachers assessed that the use of activity is "good" in terms of objective, presentation and coverage of issues. 50 per cent female teachers assessed that the use of activity is "excellent" in terms of objective, presentation and coverage of issues (Table 4). 86 percent teachers assessed that the use of activity is "good" in terms of making informed decisions in organizing Economics classes. 14 percent teachers assessed "excellent" in terms of making informed decisions in organizing Economics. 50 per cent female teachers assessed that the use of activity is "good" in terms of making informed decisions in organizing Economics classes. 50 per cent female teachers assessed that the use of activity is "excellent" in terms of making informed decisions in organizing Economics classes (Table 5).The study reveals that 86 per cent teachers responded that this activity is fruitful for qualitative teaching because it gives the idea of a topic from different perspectives, all the students get chance to clarify the doubts and also to give their opinion about the concept. 09 per cent teachers responded that this activity is fruitful for qualitative teaching because it will increase the knowledge, application, presentation, analysis and overall personality development each and every student by interaction, basic problems of students are solved, and it is easy to maintain each and every student's profile. 5 per cent teachers responded that this activity is fruitful for qualitative teaching because confidence will boost up. Participation in any activity of the school will be increased. All around development will be enhanced. 100 per cent teachers responded that auctioning out event is fruitful for qualitative teaching (Table 6).
FOCUS GROUP DISCUSSION (FGD)
The researcher organized focus group discussion with the teachers so that their true feelings may be recorded. The researcher asked following five questions:
What do you think about the traditional lecture method?
What do you feel about the activity based method which I used?
Do you think activity based method is better than lecture method? If yes, why and if no, why?
Will you ask the other subject teachers to teach with this method? If yes, why and if no, why?
Any other thing regarding the activity based method which you want to say, feel free to tell me.
Most of the teachers were of the view that the lecture method is not interesting and it does not motivate students to learn theory as it lacks real life situations, it is teacher centric, and some students felt isolated in the classroom.
98 percent teachers responded that the activity based method will help in motivating the students to learn theory and seek the required information.
97 per cent teachers responded that activity based method was better than lecture for retention and application of activity. Activities illustrate the practical application of theories and, most important, the relation between theories and practical results. 85 per cent teachers were of the opinion that the use of activities will enhance students' ability to recognize multiple perspectives.
95 per cent teachers told that they will ask the other subject teachers to teach with case method.
97 percent teachers told that activity based method is better than lecture method. It will create interest, motivate to learn and help students to relate the textual activity with the real life situations. Teachers believe that activities, when used along with lectures and readings will contribute more to the students learning.
The teachers provided qualitative feedback for improvement to the present level of learning of the teachers. Teachers were motivated by the researcher through activity based method and personal interactions.
The study supports that a better understanding of the structure of the activity will allow teachers to have more informed post-activity discussions and will provide insights about how to deal with anomalies that might arise. In this way, activities used to teach Economics will effectively demonstrate the economic way of thinking while engaging students in the process of learning Economics and classroom environment becomes co-operative and collaborative rather than individualistic and competitive as are also the findings of Mukunda (2009).
The rationale for using this methodology is that it helps students remember and apply abstract concepts; it is successful with students of different ability levels; it promotes social growth as well as economic understanding; and because it is fun, students are more interested in the subject matter as are also the findings of Lopus, Morton, and Willis, (2003).
CONCLUSION
The broad objective of this study was to differentiate and appreciate lecture vs activity based method. However, the findings of the study have ascertained and supported to the activity based method for better application/teaching by the researcher. Researchers experience with the activities in the classrooms as she began to use activity based method teaching reinforces teachers' observations and interests remarkably. From the point of view of a teacher, the classroom discussion that activities stimulate is highly rewarding. The use of activities is able to change the classroom environment from the passive listening of lectures and writing notes into the exchange of ideas. The evidence from the study suggests that the use of activities does more than stimulate academic discussion. The teachers take more interest and are motivated to teach the subject with the activities. They feel that the use of activities are interesting and adding interest to the subject and makes the classroom more real. Teachers believe that activities, when used along with lectures and readings, contribute more to students learning.
IMPLICATIONS OF THE STUDY
Training of teachers is the need of the hour. But the training should not be in mechanical way, it may have package-printed as well as audio visual that the teachers may see and co-construct the meaning and usefulness of activity based teaching methods.
LIMITATION OF THE STUDY
This study was conducted among 22 PGTs of 9 subjects. So it can't be generalized that the activity based method will give the same result in another sample. It needs research in a large sample to make generalizations. However, some practicising teachers of KVS and NVS are also using this method and their responses are positive.
ACKNOWLEDGEMENTS
Author is obliged to the authorities of NCERT for providing the opportunity to interact with teachers as resource person on topic titled "Innovative Teaching-Learning Methods in Economics" in Capacity Building Programme for PGTs of CTSA in the area of Adolescence Education from 03-13 January, 2017. Author is grateful to Prof. A. K. Jain, BHU and Prof. V. Upadhyay IIT Delhi for their encouragement during writing process of this paper. Author acknowledges the immense help received from the scholars whose articles are cited and included in references of this manuscript. Author is also grateful to authors / editors / publishers of all those articles, journals and books from where the literature for this article has been reviewed and discussed. This paper has been presented in International Conference on Conscientious and Unimpeachable Technologies-2017 at SAITM Gurugram on 14th October, 2017.
Englishhttp://ijcrr.com/abstract.php?article_id=2354http://ijcrr.com/article_html.php?did=2354
Ahlfeldt, S., Mehta, S., and Sellnow, T. "Measurement and analysis of student engagement in university classes where varying levels of PBL methods of instruction are in use" Higher Education Research and Development, Vol. 24 No. 1, 5-20, 2005.
Johnson, D.W., Johnson R., and Smith K. "Active Learning: Co-operation in the college classroom" Edina, MB: Interaction Book Co. p.52, 1998.
Lopus, J. S., J. S. Morton, and A. M. Willis, "Activity-Based Economics" Social Education, 67, 2: 85-89, 2003.
Eaton David H., "Using Experiments and Activities in the Principles Class" presented at ASSA Meetings San Diego, CA. published in The Economics Network online, January 2004, https://www.economicsnetwork.ac.uk/showcase/eaton_active accessed during March 2017 to September 2017.
National Curriculum Framework 2005 (NCERT) p. 17-18.
Kumari Pratima," Teaching Economics with Case Method: An Experience" International Journal of Social Development Vol. 13 No. 1, 9-13, 2013.
Kumari Pratima, "Teaching in Rural School: An Experience with Project Method" International Journal of Economic Issues Vol.6 No. 1, 61-65, 2013.
Kumari Pratima, " Teaching Statistics with Case Method in Indian Rural School: An Experience" Academic Views and Reviews Vol. 4 No. 1, April - June, 54-67, 2014.
Kumari Pratima, "Teaching 'Indian Economic Development' with Case Method" Journal of Teaching and Education Vol. 3 No.1, 405-419, 2014.
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Petress, K. What is meant by active learning? Education, Vol. 128 No. 4, 566-569, 2008.
Mukunda, Kamala, What did I ask at School today?, Collins (imprint of Harper Collins Publishers) 2009, http://www.mybangalore.com/article/1009/what-did-you-ask-at-school-today.html accessed during March 2017 to September 2017.
Radiance Research AcademyInternational Journal of Current Research and Review2231-21960975-5241921EnglishN-0001November30General SciencesOptical Absorption and Luminescence Properties of SM3+ Doped Chlorofluoro Borate Glasses for Photonic Applications
English1923K. Venkata RaoaEnglish S. BabubEnglish K.V. Subba ReddyaEnglish S. SubbarayuduaEnglish Y.C. RatnakarambEnglishSm3+ ions doped chlorofluoro borate glasses with compositions (in mol %) (50-x)B2O3+20PbO+15NaCl+15MgF2+xSm2O3, x= 0.2, 0.4, 0.6, 0.8 and 1.0 have been prepared by melt quenching technique. For these glasses X-ray diffraction (XRD), optical absorption, emission and decay measurements were carried out. The glassy nature of the present glass matrices are confirmed by XRD profiles. From the optical absorption spectra, derived the spectral intensities (f) and Judd-Ofelt intensity parameters, Ωλ (λ= 2, 4, 6) have been evaluated. Using Judd-Ofelt intensity parameters, radiative transition probabilities (AR), and branching ratios (βR) were calculated. From the photoluminescence spectra, stimulated emission cross-sections (σP) for all the observed emission transitions were calculated. To investigate luminescence potentiality of 4G5/26H7/2 emission level of Sm3+ doped different chlorofluoro borate glasses, experimental lifetimes (τexp) were obtained from decay curve analysis for all glass matrices. Finally, these observed results were discussed and compared with the literature data.
EnglishBorate glasses, J-O parameters, Photoluminescence, Lifetime, Emission cross-sectionIntroduction
Spectroscopy of rare earth ions integrated in different host glasses are used extensively in different scientific and technical applications such as solid state lasers, optical amplifiers and bar-code reading etc. In the development of rare earth (RE) doped optical devices, the selection of host glass matrix is very important because the spectral transitions of rare earth ions are host dependent [1].
Rare earth doped glasses were extensively researched due to their attractive advantages such as wide range of composition, flexibility, shape and wide range of potential applications like optical amplifiers, lasers and sensors. Among them, the borate family glasses have better application through the nature of low noise and high sensitivity character [2, 3]. Optical properties of borate glasses depend on the modifier oxide material of the composition. A large number of modifier oxides were used in glasses such as zinc oxide, alkali oxides, alkaline oxides and heavy metal oxides. However, borate glasses still have quite a few disadvantages that restrict their further applications by high phonon energy of host glass matrix [4]. In this quest, an attempt has been made by borate glasses are a kind of glass former in which hologens are used as an additional ligand environment to create low phonon energy in addition to the oxygen ligands. The Sm3+ (4f5) ion is one of the most interesting Ln3+ ions to analyze the fluorescence properties as its emitting 4G5/2 level exhibits relatively high quantum efficiency and also shows different quenching emission channels. In recent times, glasses containing Sm3+ ions have stimulated extensive interest due to their potentional applications for high-density optical storage, under sea communication and colour display [5]. The decay of excited states in Sm3+ involves different mechanisms depending on the matrix [6]. Therefore the Sm3+ ion can be useful in lasers, solar energy converters, etc.
In the present study, we first adopted simple melt quenching technique to prepare samarium doped different chlorofluoroborate glasses. The aim is to investigate the effects of Sm doping on optical properties of chlorofluoro borate glasses in detail. Now, we focus on to highlight the intimate connection between the rare earth concentration and spectroscopic parameters. From optical absorption spectra, Judd-Ofelt intensity parameters (2, 4 and 6), radiative lifetimes (τR), radiative transition probability (AR) and peak stimulated emission cross-sections (σP). The nature of decay curve profiles for the 4G5/2 state of Sm3+ in all the glass matrices is analyzed. These prepared glasses could find application in the optical field.
Experimental
In the present work different concentration of Sm3+ doped lead magnesium fluro borate glasses samples with the compositions (50-x)B2O3+20PbO+15MgF2+15NaCl+xSm2O3 (where x = 0.2, 0.4, 0.6, 0.8 and 1.0 mol%) were prepared using high purify chemicals, boric acid (B2O3), lead oxide (PbO), magnesium fluoride (MgF2), sodium chloride (NaCl2) and samarium oxide (Sm2O3) powders using a conventional melt-quenching method. The raw materials were thoroughly mixed in an agate mortar and melted in an electronic furnace at the temperature 950-1000OC for 1h in porcelain crucible. After that, obtained liquid is poured on a preheated brass plate. The synthesized glass samples were subsequently annealed at 300c to remove thermal strain to do spectral measurements. Refractive index (n) measurements were performed using an Abbe refractometer at sodium wavelength (583.3 nm) with one-bromonapthalene as contact liquid. The density (d) was measured by Archimedes's principle using water as an immersion liquid. All these measurements were carried out at RT. For all the glass samples, the physical properties like density, thickness, refractive index and concentrations of Sm3+ ions doped have been calculated.
Structural investigations of prepared glasses were carried out by XRD. Optical absorption spectrum was recorded using Perkin-Elmber Lambda 950 spectrometer. The excitation and visible photo luminescence spectra (range 400-700 nm) of Sm3+ doped glass matrices were recorded using JOBIN YVON Fluoro log-3 fluorimeter using flash lamp.
Results and analysis
XRD analysis
The X-ray diffraction pattern (XRD) of 0.8 mol % of Sm3+ doped chlorofluoro borate glass is shown in Fig. 1. The XRD pattern does not contain any diffracting lines, suggesting the existence of long range structural disorder in the glass under investigation. This confirms the amorphous nature of the Sm3+ doped chlorofluoro borate glass matrix.
Absorption spectroscopy and Judd-Ofelt theory
The study of optical absorption is a useful method for investigating optically induced transitions. Fig. 2 presents the absorption spectrum for 0.8 mol% Sm3+ doped chlorofluoro borate glass matrix. Different absorption bands of Sm3+ ions in lead borate glass system were assigned with their appropriate transitions. Table 1, shows the spectral intensities of different absorption bands of 0.8 mol% Sm3+ doped chlorofluoro borate glass matrix along with RMS deviations. Theory behind the work has been taken from our previously published paper [7]. There is a good correlation between calculated and experimental spectral intensities indicating that it is in accordance with intensity theory proposed by Judd-Ofelt [8,9]. Expected bands of Sm3+ in the visible region such as 6P7/2, 6P5/2 and 4G9/2 are missing owing to strong absorption of host glass matrix.
Within the framework of the Judd-Ofelt theory, the absorption between any two states can be obtained as a function of three parameters (2, 4 and 6) called the intensity or Judd-Ofelt parameters. These parameters characterize a rare earth ion in a given host matrix and are shown in Table 1. The 2 parameter is strongly depending on short range effects, such as covalency of the rare earth ion and sensitive to the symmetry of rare earth ion site. While 4 and 6 are long range parameters related to the bulk properties of the glass such as rigidity and viscosity [10]. Order of intensity parameters is found to be W2>W6>W4. The obtained value of ?2 in chlorofluoro borate glass is 3.32x10-20 cm2 indicates that higher asymmetry/higher covalency is connected with surrounding.
Some transitions, whose spectral intensities are very responsive to a small change in the surrounding ligand environment, these transitions are called 'hypersensitive transitions (HST)'. HST transitions obey the selection rules |ΔJ|2, |ΔL|2 and ΔS = 0. Among various transition intensities, 6H5/2 6F7/2 is the hypersensitive transition (HST) for Sm3+ ion and most intense one in the near infrared region [11] which is the same as those of a pure quadrupole transition. It has large ||U2|| reduced matrix elements. As the hypersensitivity, depends mainly on the atoms surrounding the samarium ions. The configuration of nearest- neighboring atoms has greater influence than atoms lying beyond the first and second- neighboring shells.
Emission analysis
The excitation spectrum of chlorofluoro borate glass was obtained by monitoring the emission of Sm3+ ion at 601 nm as shown in Fig.3 and the peak at 404 nm was found to be optimal excitation peak. The assignments of the samarium excited states were made in accordance with previous reported works. For pure rare earth ion, the surrounding environment is homogeneous. So, their excitation bands are symmetric. In the present work, the excitation spectrum appears to be asymmetric owing to some disorder surrounding the environment of Sm3+ ion. The position of the emission transitions exhibits smaller variations and the invariance of the emission wavelengths can be explained by the shielded nature of the 4f-4f. The emission spectra of different chlorofluoro borate glasses are recorded using an excitation of 404 nm. Fig. 4 shows attributions of the corresponding luminescent transitions for different chlorofluoro borate glasses. Figure shows three emission peaks nearly at 569, 601 and 645 nm. From the emission spectra, it is observed that the main visible emission intensity of Sm3+ ion is in the reddish-orange part of spectra and corresponds to 4G5/2 6H7/2 transition located at 601 nm. The intensity ratio between electric dipole and magnetic dipole transitions measures the symmetry of local environment of the trivalent 4f ions. The 4G5/26H11/2 transition is not observed due to its forbidden character (ΔJ=3), 4G5/2 6H5/2 transition is a magnetic dipole (MD) transition. The 4G5/26H7/2 transition is magnetic dipole allowed but electric dipole dominated with the selection rule ΔJ=1 and the 6H5/26H9/2 band is a forced electric dipole transition (ED). This transition is very sensitive to surrounding environment of Sm3+ ions due to its hypersensitive behavior. The greater the intensity of the ED transition, the more asymmetry is present in the glass matrix. In the present work, the spectral intensity of 4G5/26H9/2 (ED) transition of the Sm3+ ion is lower than the 4G5/2 6H5/2 (MD) transition, which indicates that low asymmetric is predominant in the prepared glasses [12].
Intensity alteration was observed by changing samarium doping concentration. Among the three observed emission transitions (Figure 4), 4G5/2 6H7/2 transition which has high emission intensity and 4G5/26H9/2 transition which has low emission intensity. The narrow nature of emission band indicates that the Sm3+ coordination environment distribution is small. From the emission spectra, it is observed that the intensity of all the peaks increase up to 0.8 mol% Sm3+ ion concentration and then decrease at higher concentrations. The luminescence intensity is highly sensitive to the surrounding local environment of samarium ions. When the samarium ions are doped into a phosphate network, Sm3+ ions cannot be dispersed in the host glass matrix, but become closer Sm3+-Sm3+ ion pairs at higher concentrations. This leads to quenching of the fluorescence intensity. Also, at lower concentrations of samarium ions (up to 0.8 mol%) the samarium coordinates with nonbridging oxygens which is responsible for the higher luminescence intensity. At higher concentrations (>0.8 mol%), samarium ions coordinate with bridging oxygens. The interaction between borate groups and oxygen groups through samarium ions decreases, i.e. connectivity decreases. Hence there is a possibility of decreasing fluorescence intensity. The cross relaxation channels are responsible for luminescence quenching in the studied glass matrix. This is mainly due to Sm3+-Sm3+ interactions at higher concentrations. Certain luminescence properties for three emission transitions in all the glass matrices are shown in Table 2. It is noted that the transition, 4G5/26H7/2 is the most probable transition. Also, it is noted that the predicted radiative transition probability for the transition 4G5/26H7/2 of 0.8mol% Sm3+ doped chlorofluoro borate glass is 169 s-1.
The stimulated emission cross section (p) of emission transition is one of the important parameter used to identify a laser active medium. A good laser transition can have a large emission cross section. It is observed that the transition, 4G5/26H7/2 shows higher peak emission cross-section i.e. 7.68 X 10-22 cm2 at λp= 601nm in 0.8mol% of Sm3+ doped chlorofluoro borate glass matrix, which is high. The large emission cross sections are attractive features for low threshold, high gain applications and are utilized to obtain continuous wave laser action [13].
Decay curve analysis
In the present work, it is observed that at lower concentrations of samarium (0.2 and 0.4 mol%), the decay profiles (Figure 5 are fitted to single exponential whereas at higher concentrations (0.6, 0.8 and 1.0 mol%), the decay profile becomes non-exponential due to the existence of non-radiative energy transfer. The energy gap between the 4G5/2 level and next lowest level 6F11/2 is nearly 6600 cm-1 and requires at least six phonons to bridge the energy gap. So, MPR channel is negligible in Sm3+ doped chlorofluoro borate glasses. The decreased luminescence decay constants are due to the energy transfer through cross-relaxation channels. It is predominant at higher concentrations of samarium ions, i.e. 0.6 mol% in the investigated glasses. The decrease of lifetime and non-exponential fit are characteristics of the existence of concentration quenching mechanism at higher concentrations of samarium ions.
Conclusions
From XRD analysis, it is confirm that the prepared glasses are of amorphous in nature. From the absorption spectra, various absorption transitions are assigned. From these transitions, one transition is chosen for excitation of samarium ions and emission spectra are recorded. From emission spectra, four luminescence transitions are observed. Among these transitions, emission transition at 601 nm has high in intensity. With the increases of content of samarium, concentration quenching is observed. From the results of these investigations, it is concluded that the 0.8 mol % of Sm3+-doped chlorofluoroborate glass is more useful for photonic applications.
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Radiance Research AcademyInternational Journal of Current Research and Review2231-21960975-5241921EnglishN-0001November30General SciencesVerification of VARSHA Rainfall Forecasts for Summer Monsoon Seasons of 2009 and 2010
English2436S. Karuna SagarEnglish G. MrudulaEnglish K. Vijaya KumariEnglish S. Vijaya Bhaskara RaoEnglishObjective: The monsoon year 2009 is a severe drought with 21.8% deficit rainfall from the long period average according to India Meteorological Department (IMD) over India since the past decade and 2010 is a normal monsoon year. Therefore, the verification skill of the VARSHA model has been computed for one normal monsoon and one drought year.
Method: The statistical parameters like mean error, root mean square error and correlation coefficient has been computed at every model grid point and verified against the rainfall observations from India Meteorological Department and Tropical Rainfall Measuring Mission (TRMM). The analysis is also extended to dichotomous forecasts, i.e. yes/no forecasts, by using contingency tables. The four regions namely, South peninsula, Central India, North-East and North-West regions of Indian land mass have been considered for the verification analysis.
Result: India receives a major portion of its annual rainfall during the summer monsoon season (June to September) and thus accurate prediction of summer monsoon rainfall is very crucial. Rainfall is a discrete parameter which shows large variations spatially as well as temporally. VARSHA, a hydrostatic global circulation model, developed at Flosolver unit, National Aerospace Laboratories (NAL), Bangalore, is used to predict summer monsoon rainfall from the year 2005 onwards. Forecast verification serves to assess the state of the art of forecasting. Therefore, verification of the model forecast is an important task for any numerical weather prediction centre. In this study, an attempt has been made to examine the skill of VARSHA model in predicting the rainfall during summer monsoon period of 2009 and 2010.
Conclusion: The results show that model forecasts are useful at medium range and the performance of VARSHA is better in 2010 compared to 2009. The statistical skill scores show high predictability for light rain events with a decreasing tendency with an increase in intensity.
EnglishRainfall, VARSHA GCM, Verification skill, Contingency tableINTRODUCTION
Climate of Asia is dominant by the south west monsoon rainfall, especially over India. The Indian summer monsoon season is one of the most spectacular manifestations of atmospheric circulations including regional and global characteristics as well as its associated connections (Mandal et.al., 2006). During the South-West Monsoon (also known as Summer Monsoon) which starts from June to September, India receives a major portion of its annual rainfall. The seasonal rainfall as a whole over India is about 89cm with 10% coefficient of variation (Rajeevan et.al., 2005). However, the IJCRR Section: General Science Sci. Journal Impact Factor 4.016 ICV: 71.54 Research Article contribution of rainfall due to pre-monsoon (March, April and May) and post-monsoon (October, November and December) to the annual rainfall is about 11% (Guhathakurta and Rajeevan, 2008). Therefore, taking the information on the progress, forecasting of monsoon which is necessary to the farmers and other users well in advance is highly important. Realistic prediction of Indian summer monsoon rainfall on different space and time scales is a challenging task. Various studies on summer monsoon characteristics, modeling aspects, teleconnections with various global parameters, indices, interannual variability, intra-seasonal variability have been carried out and documented (Sikka and Gadgil, 1980; Shukla and Mooley, 1987; Annamalai, 2001; Goswami et al., 2001; Gadgil, 2003; Gadgil and Gadgil, 2006; Goswamy, 2005; Mitra et.al., 2005; Webster et al., 1998, 2006; Basu, 2001, 2005; Gadgil et al., 2007, Rajeevan et al., 2006, 2008; Kelkar, 2009; Rajeevan, 2010; Janakiraman, 2011). Various atmospheric models with different resolutions, i.e., climate, global and regional models have been developed to predict rainfall accurately. All the studies have suggested that the model skills are good (Buizza, et.al., 1999; Cherubini, 2002) in predicting the low intensity rainfall than the high intensity rainfall. However, in general, mostly the models overestimated the actually observed rainfall intensities. A small fluctuation in seasonal rainfall will show a large effect on the economy in agricultural countries like India (Rajeevan et.al. 2004). Therefore prediction of rainfall event with intensity is very crucial. Verification of model forecasts is very important, because, it tells how to make the best use of the forecasts at any weather prediction centre. Meteorologists have developed and devoted to forecasting verification regarding both verification methods and application of these methods in operational and experimental centres (Murphy and Daan, 1985). A general frame work for forecast verification was developed by Murphy and Winkler (1987). VARSHA, a hydrostatic spectral Global Circulation Model (GCM) (Nanjundaiah and Sinha, 1999), developed at Flosolver unit, National Aerospace Laboratories (NAL), Bangalore, is used for the daily forecast of the Indian monsoon. The model is integrated up to 31 days ahead to forecast the atmosphere from the initial condition prepared using Final Analysis (FNL) from National Center for Environmental Prediction (NCEP). Later the model has integrated up to 36days (to implement ensembles with 5 days). VARSHA model has roots in National Center for Medium Range Weather Forecasting (NCMRWF) T-80 code, later it was parallelized and re-engineered using new boundary layer (Rao and Narasimha, 2005) and radiation (Varghese et al, 2003) schemes by National Aerospace Laboratories in 1993 (Sinha et al, 1994). The code has a special boundary layer parameterization scheme for the tropics and a refined scheme for the moist adiabat. The spectral truncation of the model version used is at 120 waves in triangular truncation with 512 grid points in east-west and 256 grid points in north-south. The vertical resolution of the model is up to 18 levels in sigma coordinates and persisted Sea Surface Temperature (SST) is used. Persisted method assumes that tomorrow’s weather will be the same as today’s weather i.e. the conditions at the time of forecast will not change. The detailed model characteristics are explained in Table.1 (Basu et.al. 2010). As a part of NAL-CSIR collaborations with various universities, Department of Physics, Sri Venkateswara University, Tirupati was selected as one of the major universities to study the characteristics of Monsoon through NMITLI (New Millennium Indian Technology Leadership Initiatives) Modeling based joint CSIR-NAL project on North East Monsoon prediction using VARSHA GCM. The scope of the verification is (a) to monitor forecast quality over time (b) to compare the quality of different forecast systems i.e., to what extent does one forecast system gives better forecast than the other, and (c) to improve the quality of the forecasts through better understanding of the forecast errors. Verification of VARSHA forecasts for the south west monsoon seasons of 2009 and 2010 was carried out in the present study. The years 2009 and 2010 were selected as 2009 is a severe drought with 21.8% deficit rainfall from the long period average according to India Meteorological Department over India since the past decade and 2010 is a normal monsoon year.
DATA
The verification analysis of VARSHA rainfall forecasts is done for 122 days i.e., summer monsoon season (1st June to 30th September) for the years 2009 and 2010. The qualitative and quantitative verification has been done from 1-day forecast to 15-day forecast lengths. However, in the present study, the verification at different forecast lengths, i.e., 1-day, 3-day, 5-day, 7-day, 10-day and 15-day against the observations are only presented. For spatial verification Tropical Rainfall Measuring Mission 3B42RT data with 0.25º × 0.25º degree (lat × lon) (Huffman et al 2007) are used. As the resolution of VARSHA forecasts is 0.7º × 0.7º, Tropical Rainfall Measuring Mission data has been interpolated to the resolution of 0.7 degree using bilinear interpolation method. For temporal verification analysis in addition to the Tropical Rainfall Measuring Mission data, high resolution real time gridded rainfall data at 0.5 degree resolution from Indian Meteorological Department (Rajeevan et al, 2009) are also used.
METHODOLOGY
Various methods have been developed (Murphy, et.al., 1988; Casati, 2008; Nurmy, 2003; Rajeevan, et.al., 2005; Stanski, et.al., 1989) to compare the distribution of forecasts against the observations. In this paper some important verification methods are used to assess the performance of VARSHA GCM for the summer monsoon seasons of 2009 and 2010. Towards the quantitative verification of the model, the Mean Error (ME), Root Mean Square Error (RMSE) and the Pearson’s Correlation Coefficient (CC) between observations and forecasts at each grid point, averaged over central India and Indian land mass as a whole is computed. The verification scores computed are as follows:
The verification analysis is also carried for dichotomous forecasts, i.e., yes/ no forecasts. A dichotomous forecast says, "yes, an event will happen”, or “no, the event will not happen". The combination of forecasts (yes/no) and observations (yes/no) are Hit - event forecast occurred and did occur Miss - event forecast not to occur but did occur False alarm - event forecast occurred but did not occur Correct negative - event forecast not to occur and did not occur The analysis has been carried out for various thresholds of rainfall intensity. An event "ye" is defined as if the rainfall greater than or equal to the threshold value, else it is a non event i.e “no”. This kind of verification is done by using the contingency table (Table.2). A perfect forecast system will produce only Hits and Correct Negatives, and no Miss or False Alarm. Murphy (1993) had suggested nine skill scores for forecast verification. Some of the skill scores have been computed in this report and are listed below.
It gives the measure of forecast events that were observed to non events. It is sensitive to false predictions but ignores misses. This score can always be increased by under forecasting the number of sever events, but only at the cost of more missed events which are not seen by the score. The rainfall variation over the entire country is not homogeneous. Therefore the country was classified into four geographical sub regions by India Meteorological Department i.e., North-West India, North-East India, Central India and South Peninsular India as shown in Fig.1. The verification is carried out for rainfall at every grid point over India, rainfall averaged over the Indian land mass, over South Peninsula (area marked by green colour), Central India (area marked by blue colour), North-East India (area marked by orange colour) and North-West India (area marked by red color).
RESULTS
Spatial verification of VARSHA rainfall forecasts of various forecast lengths, i.e., 1-day, 3-day, 5-day, 7-day, 10-day and 15-day has been done against the observations from Tropical Rainfall Measuring Mission for the years of 2009 and 2010. During the year 2009, most of the subdivisions are in deficient condition. The All India Average Rainfall (AIAR) for the summer monsoon season is 23% lesser than from its normal which is comparable to the most severe drought (24% in 1972) in the last 100 years and for June it was 48% which is recorded as the lowest rainfall since 1871 (Francis and Gadgil, 2009). Even though monsoon arrived early over India in 2009 on 23rd May, the country experienced severe drought. Immediately after the declaration of onset over Kerala, a severe cyclonic storm had formed over Bay of Bengal which helped to get an advance of monsoon over Indian states; later the monsoon never gained its normal position. Droughts in India are mainly associated with El-Nino events. The El-Nino phase of the southern oscillation has a direct impact on India which leads to weak or enhanced summer monsoon. The comparison of VARSHA forecast of all India average rainfall with India Meteorological Department observation for the summer monsoon seasons of 2009 (left panel) and 2010 (right panel) is shown in Fig.2. The first panel indicates for June, second, third and fourth panels indicate July, August and September months respectively. From the Figure, the observed All India Average Rainfall (blue bars) during the summer monsoon months is below normal (red line) for 2009. The VARSHA forecast of All India Average Rainfall is well projected the deficiency of rainfall in all monsoon months. However, in the normal monsoon year of 2010, the observed All India Average Rainfall during June July August September is just above the normal where as VARSHA forecast for 2010 depicts the All India Average Rainfall is just below normal. Therefore, the severe drought in 2009 was reasonably well predicted by VARSHA model, in particular, VARSHA model does not over predict the rainfall (Sinha, 2010). The normal monsoon year is also predicted with less magnitude. During the monsoon season of 2009, the onset over Kerala is on 23rd May which is 8 days earlier to the normal onset date i.e. 1st June. However, in 2010, the onset over Kerala is on 31st May. The forecast of monsoon onset over Kerala is also attempted well in advance every year using VARSHA GCM with a specified criterion as mentioned below. A Continuous increase of Kinetic Energy with a minimum of 25 J/Kg at 600hPa in the box A (Fig.3). Mean zonal wind at 600hPa in a box A should be positive An average rainfall of more than 5 mm for 3 consecutive days in box B(Fig.3) Then the 1st day is declared as monsoon onset date with a model error of ±3 days. With the above criterion, the VARSHA GCM had predicted the monsoon onset over Kerala accurately for the both years 2009 (Karuna Sagar and Mrudula, 2010) and 2010 (Fig.3). Fig.4 shows the spatial distribution of mean error for the summer monsoon season of 2009 with different length of day forecasts. The upper panel represents 1-day, 3-day and 5-day forecast lengths and lower panel indicates 7-day, 10- day and 15-day forecast lengths. The error has been calculated by subtracting the observed rainfall from the forecast quantity. The figure depicts that there are large differences between observed and model forecasts of rainfall. The positive errors can be seen over south-west peninsula region and are increasing with forecast lengths in particular over the Arabian Sea and southern Bay of Bengal region. Another patch of positive error is noticed over foothills of Himalayas. Fig.5 depicts the mean error for the summer monsoon season of the normal year 2010. Form the figure, it can be seen that the model overestimates rainfall over the southern peninsula and foot hills of Himalayas and also the magnitude of the error is increasing with forecast length over these regions. However, a strong positive error can be noticed over most of the Indian landmass except southern peninsula. Since model forecasts are good over Indian land mass during 2009, it depicts that VARSHA GCM well predicted the drought rainfall whereas, in good monsoon period (2010), the model shows excess in both positive and negative side. However, the above described mean error showing the seasonal mean error may not be fully informative, because the errors of opposite signs may get cancelled or added due to the summing up for the entire season. Hence, root mean square error values for the above mentioned regions have been calculated.
Spatial root mean square errors estimated and are shown in Fig.6 (2009) and Fig.7 (2010). These figures depict that magnitude of root mean square error is more along the south west coast, over Bay of Bengal and the Himalayan region which may be attributed to the topography/orography effect or due to the model physics. Root mean square error over these specified regions is more for 3-day forecast than that of 1-day forecast and 5-day forecast. Beyond this forecast length the root mean square error values are seen increasing. Higher values of root mean square error are found over Ocean region than land region and its magnitude is oscillating around a threshold with forecast length. Over central India, the magnitude of Root mean square error values are quite less and over southern land mass it is more. A similar kind of pattern in Root mean square error is seen in 2010 with an extendable area over Central India. The magnitude of Root mean square error is increasing with forecast day length for both 2009 and 2010 over Indian Ocean. Efforts are needed to improve the physics in the model which plays a major role in rainfall prediction. Analysis of Pearson’s correlation coefficient (Fig.8) shows that model predictions were well correlated with the observations up to 5 days in 2009 and further the correlation coefficient is weakening and become negative. For the year 2010 (Fig.9), the model predictions are in phase with the observations up to 3-day forecasts and partially with 5-day forecasts. From the 5-day forecast length, the predictions are out of phase for most of the regions. However, in both the years, higher values of correlation coefficient can be seen over ocean than in Indian land mass. The spatial variation of correlation coefficient from region to region is large in 2009 for 1-day forecast, whereas in 2010, the spatial variation of correlation coefficient is less. The above three statistics reveals that the model forecasts have better skill in predicting the monsoon rainfall in 2009 than in 2010. Temporal verification of all India average rainfall is also carried out for the years 2009 and 2010. The skill scores like mean error, root mean square error and correlation coefficient has been computed for the entire Indian land mass as a whole (Table.2) and over a box spanning from 20ºN – 25ºN and 75ºE – 85ºE (Table.3). The observations from both India Meteorological Department and Tropical Rainfall Measuring Mission are used for this analysis. From Table.2, the mean error over Indian land mass is negative for all the forecast lengths which indicate that the model forecasts of rainfall intensity are comparatively less than the observations from both India Meteorological Department and Tropical Rainfall Measuring Mission. However, the observed rainfall from Tropical Rainfall Measuring Mission is more than the gauge rainfall (India Meteorological Department). Therefore, the magnitude of root mean square error is smaller when forecasts are compared with India Meteorological Department than with Tropical Rainfall Measuring Mission. This is due to the unpredictable behaviour of the model over Ocean region. Whereas, the Root mean square error is seen increasing with forecast length for both 2009 and 2010. Highest value of correlation coefficient (0.91 and 0.81 with India Meteorological Department, 0.8 and 0.71 with Tropical Rainfall Measuring Mission) are found in 1-day forecasts. Therefore 1-day forecasts are in phase with the observations and have a decreasing tendency with the length of forecast. But the forecasts are significant up to 10-day forecasts for All India Rainfall over the above regions. Similar kind of phase is reflected when verification is carried out over central India. The VARSHA forecasts are very close in magnitude and in phase with India Meteorological Department observations than Tropical Rainfall Measuring Mission for different forecasts lengths. For the verification of dichotomous forecasts, a contingency table is prepared to compare with Tropical Rainfall Measuring Mission observations. Various skill scores have been computed with various thresholds for different lengths of forecasts. The analysis is carried out at every grid point and over four selected regions by considering the threshold value from 5mm to 50mm/day. Fig.10 shows the Bias scores for the years 2009 (left panel) and 2010 (right panel) which includes rainfall averaged over Indian land mass (upper first panel) and second, third and fourth panel indicates other four selected geographical regions i.e., n-west India, n-east India, central India and south India respectively. Bias score for all India average rainfall is high at lower threshold of rainfall and varying between 0.5-1.0 for higher threshold with different day forecasts. The Bias skill score has a decreasing tendency as length of day forecast increases, but has a slight variation in magnitude with the increase in the rainfall threshold value. From the figure, it can be seen that the magnitude of bias is small over the selected geographical regions than India as whole, except over southern India. The model forecasts are much closer to the observations when the number of grid points taken for the average is increasing. The model tendency to overestimate an event is less for light rain cases and increasing with forecast length. But the magnitude of Bias over south peninsula is more than 1 and increasing with the threshold, which suggests that the model forecasts are overestimated over the south Indian region.
Fig.11 shows the verification of skill score probability of detection for the above two years over India as a whole and the four geographical regions. Probability of detection is noticed to be consistently very high for all forecast lengths with threshold value 5mm to 20mm. But over the North West Indian region, the magnitude of probability of detection is less when compared to the other regions especially in 2009. The magnitude of probability of detection decreases with increase in the threshold amount of rainfall in all the regions in both the years. High value of probability of detection indicates that model can forecast majority of the observed yes/ no rainfall events. Thus, it can be concluded that light rain events are correctly predicted by the model for all forecast day lengths. The minimum probability of detection can be seen in North West Indian region at the higher threshold rainfall value. Over the remaining specified domains, the minimum value of probability of detection is more than 0.2 which tells that model skills are considerable for higher rainfall threshold also. probability of detection has an increasing trend from individual grid points to all India verification. The behaviour of the equitable threat score for 2009 and 2010 is presented in Fig.12. Highest magnitude of equitable threat score is obtained when all India average is considered and it is seen to be less and varying between 0 and 1.5 when individual grid points are considered. From the verification, it can be seen that the spread between the equitable threat score values of different day forecasts is increasing from grid point to all India average. The spread is more while considering the thresholds between 20mm and 40mm with both inclusive. The lowest value of equitable threat score indicates that the percentage of model forecasts for ‘no’ events is high. The performance of threat score skill is shown in Fig.13. The threat score value with rainfall average over Indian landmass is above 0.9 for 2009 and 0.95 for 2010. The value of threat score is reducing with the increase in the number of grid points considered for averaging. From the figure, the magnitude of threat score is noted to decrease with the increase of rainfall threshold and the length of forecast. Highest threat score value at low rainfall threshold indicates that the less rainfall events were correctly diagnosed. The False Alarm Ratio, which ignores misses and sensitive to the false alarm, has been calculated for the summer monsoon season of 2009 and 2010 and summarized in Fig.14. It depicts that the value of False Alarm Ratio is increasing with the increase of rainfall threshold and forecast length, where as False Alarm Ratio is decreasing with the increase of number of grid points considered for averaging. The temporal variation of different skill scores at each grid point over the Indian land mass by using different thresholds of rainfall for the years of 2009 and 2010 is shown in Table.5. The magnitude of all skill scores for the year 2009 is more than 2010, which depicts that at every grid point the model forecasts are captured the true events in 2009 than in 2010.
DISCUSSION
Francis and Gadgil (2009) reported that a drought was not predicted by the leading centres in the world using the complex models of the coupled atmosphere system. However, the models had predicted above average rainfall for June, July and August. The forecasts of VARSHA suggest that the all India average rainfall for June is below the long-term mean (Sinha, 2010). It also predicted a 51% of deficiency for June. VARSHA predicted well the drought rainfall whereas, in 2010, the model shows excess. The increase in the magnitude of the root mean square error over Indian Ocean is noticed in both 2009 and 2010. The analysis suggests that the forecasts are much closure with India Meteorological Department than Tropical Rainfall Measuring Mission. The spread between the equitable threat score value is increasing from grid point to all India average. The false alarm is also more in the forecast and increasing with forecast length. CONCLUSIONS Statistical verification of the performance of VARSHA rainfall forecasts with observations using different forecast lengths has been carried out for summer monsoon seasons of 2009 and 2010. The VARSHA rainfall forecasts are nearer to the observations and the skill is better for rainfall averaged over the entire Indian landmass than at each individual grid point. The prediction skill is more in 2009 i.e., for the severe drought year than normal monsoon year i.e., in 2010. The skill is seen decreasing with the increase of the rainfall threshold value and forecast length. The model forecasts are over estimated over the south peninsula region and foot hills of Himalayas. However, the under estimation of rainfall is noticed over the most of the Indian land region and northern Bay of Bengal. The magnitude of the error is increasing with the forecast lengths as it was well known. The model forecasts are in phase with the observations up to 5 to 7-day forecast lengths. The VARSHA forecasts of rainfall are much closer to the India Meteorological Department observations than Tropical Rainfall Measuring Mission over oceanic regions. Similarly, a good prediction skill of VARSHA is noticed for the low frequency rainfall. This study shows that VARSHA forecasts can be useful in medium range forecasting especially over the country as a whole. Its forecast skills are very useful to the farmers and the Government to make the seasonal analysis.
ACKNOWLEDGEMENTS
We acknowledged the director, NAL-CSIR for his support to carry out this work. We extend our sincere gratitude to Dr. M. Rajeevan, Secretary, MoES, New-Delhi, for his valuable suggestions and guidance. We extend our sincere thanks to Dr. U. N. Sinha, Distinguished Scientist for his encouragement and support. We are also thankful to Dr. T. N. Venkatesh, Mr. Arshad Shameem for their support. The data used in this study were acquired using the GES-DISC Interactive Online Visualization and analysis Infrastructure (Giovanni) as part of the NASA’s Goddard Earth Sciences (GES) Data and Information Services Center (DISC). We also extend our gratitude to UGC-SVU center for MST Radar Applications and Advanced center for Atmospheric Science for providing the funds to carry out the research work. Authors acknowledge the immense help received from the scholars whose articles are cited and included in references of this manuscript. The authors are also grateful to authors / editors / publishers of all those articles, journals and books from where the literature for this article has been reviewed and discussed.
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Radiance Research AcademyInternational Journal of Current Research and Review2231-21960975-5241921EnglishN-0001November30HealthcareStudy on Aerobic Bacteria Causing Chronic Suppurative Otitis Media among the Pediatric Age Group
English3739Y. Ajay KumarEnglish T. Jaya ChandraEnglishObjectives: Chronic suppurative otitis media (CSOM) was reported to be the major cause of childhood morbidity. Recurrent ear discharge is the commonest clinical presentation. With these, a study was conducted to find the aerobic bacterial as well as fungal profile among the school going children
Methods: Study was conducted in the department of Microbiology and ENT, GSL Medical College, Rajahmundry from February 2017 to July 2017. Children with ear discharge were selected for the study. An informed written consent was obtained from the parents of all the participants. Study protocol was approved by the Institutional Ethics committee. Aural swabs were collected and send to the Microbiology laboratory for aerobic culture and sensitivity test.
Results: Microorganisms were isolated from 98% (219) samples. Gram negative bacilli (46.6%; 129) were isolated maximum, followed by Gram positive cocci (41%; 114) and fungi (12.3%; 34). Pseudomonas aeruginosa (62; 22.4%) was the leading cause of CSOM.
Conclusion: Decreased sensitivity was detected to Gentamycin and Cotrimoxazole, commonly used antibiotics in the form of ear drops. Hence antibiotic susceptibility testing is always advisable.
EnglishAntibiotics, Cause, IsolatesIntroduction:
Otitis media (OM), inflammation of middle ear and mastoid bone is one of the commonest childhood infections1. Chronic suppurative otitis media (CSOM) was reported to be the major cause of childhood morbidity 2, 3, 4, 5. Recurrent ear discharge is the commonest clinical presentation of CSOM. As per the WHO report, India is the highest CSOM burden countries 6. Factors such as lack of personal hygiene, introducing foreign objects are the important causes CSOM. Due to continuous discharge of pus, CSOM causes social stigma. For school going children this is practical difficulty as they are teased by friends in the class rooms.
Improper usage of antibiotics increases drug resistance as well as CSOM. With these, we conducted a study with an objective to find the aerobic bacterial as well as fungal profile among the school going children with signs and symptoms of CSOM.
Materials and methods:
This is a prospective study conducted in the department of Microbiology and ENT, GSL Medical College, Rajahmundry. Children with ear discharge were selected for the study. An informed written consent was obtained from the parents of all the participants. Study protocol was approved by the Institutional Ethics committee. Study was conducted from February 2017 to July 2017. Aural swabs were collected and send to the Microbiology laboratory for aerobic culture and sensitivity test.
Swabs were inoculated on Blood agar, MacConkey agar. The inoculated plates were incubated at 370C for 24 hours. After incubation, initially growth was classified by grams staining (GS). Battery of biochemical tests were used to identify the pathogens 7, 8, 9. Coagulase test, catalase test, Microdase test, heat test, Bile esculin agar were used for identification of gram positive cocci (GPC). To confirm gram negative bacilli (GNB), tests such as Indole, Methyl Red, Voges Proskauer, Citrate utilization, Urease production and growth on Triple Sugar Iron agar were used. Antibiotic sensitivity test (AST) was done on Muller-Hinton agar (MHA) by kibry bauer disk diffusion method 7, 8, 9, Escherichia coli ATCC 25922 was used as the control. If fungi were suspected, growth was identified by GS, lactophenol cotton blue mount and slide culture techniques.
Results:
During the study period total 223 patients aural swabs were processed. Microorganisms were isolated from 98% (219) samples. GNB (46.6%; 129) were isolated maximum, followed by GPC (41%; 114) and fungi (12.3%; 34). Pseudomonas aeruginosa (62; 22.4%) was the leading cause of CSOM.
Discussion
CSOM is one of the major public health problems. Due to short as well as more horizontal eustachian tube, CSOM is one of the significant problems in the children especially in the school going age 10. This may be the reason for getting more number of CSOM cases to the department of ENT, GSL Medical College.
As per the Hirapure PV and Pote MK report, 60% GNB and 40% GPC were isolated among the CSOM patients 11. Tesfaye G 12. and Iseh KR 13 also mentioned more GNB isolation 75% and 60.5%, respectively. In this study also GNB were isolated more compared to GPC, 46.6%, 41% respectively. In contrast, Rajat et al reported that GPC is the leading cause of CSOM 14.
In the current study, Pseudomoans aeruginosa (22.4%; 62) was isolated maximum, followed by Staphylococcus aureus (17.7%; 49), Klebsiella species (11.5%; 32), Streptococcus pneumoniae (11.2%; 31) Coagulase Negative Staphylococci (7.6%; 21), Proteus (7.6%; 21), Escherichia coli (5%; 14), Enterococci (4.7%; 13). Rajat et al 14 reported, the Staphylococcus aureus (48.69%) is the leading causative agent of CSOM followed by Pseudomonas aeruginosa (19.89%). As per the review report, Staphylococcus aureus estimates were 19 - 25% in acute and CSOM 15, 16, 17. Kumar et al reported that Pseudomoans aeruginosa is the leading causative agent of CSOM 18.
Ding et al. reported that Streptococcus pneumoniae is the leading cause of acute OM and the authors reported 47.2% isolates 19. In the current study, 31 (11.2%) Streptococcus pneumoniae were isolated. In one study, the authors reported 26% Streptococcus pneumoniae 20. Whereas study from outside Asia reported that among the children aged 4 weeks to 18 years, the range of Streptococcus pneumoniae isolates were 23 - 48% 21.
Due to moist environment, fungi are also common causative agent of CSOM 14, Candida and Aspergillus are the common causative agents. In one of the Indian studies 18, the investigators reported 15% fungal etiology among the CSOM cases. In this study also fungal (12.3%; 34) pathogens were isolated. Of the total 34 (100%) fungal isolates, 62% (21) were Candida species and the remaining 38% (13) were Aspergillus species. Among the 21 Candida isolates, 11 isolates were Candida albicans and the remaining 10 were identified as other species of Candida. Whereas, of the 12 Aspergillus isolates, 4 were identified as Aspergillus niger and the remaining 9 isolates were Aspergillus fumigatus.
All the bacterial strains were sensitive to Amikacin, Ciprofloxacin, Ceftraizxone. But the sensitivity was decreased to Gentamicin, Cotrimoxazole. Currently, drug resistance is a burning issue in the medical science. Hence AST is always advisable. AST can control the unnecessary usage of antibiotics as well as drug resistance as our study showed decreased sensitivity to Gentamycin and Cotrimoxazole, commonly used antibiotics in the form of ear drops.
Conclusion: Decreased sensitivity was detected Gentamycin and Cotrimoxazole, commonly used antibiotics in the form of ear drops. Hence antibiotic susceptibility testing is always advisable.
Acknowledgement: Authors acknowledge the immense help received from the scholars whose articles are cited and included in references of this manuscript. The authors are also grateful to authors / editors / publishers of all those articles, journals and books from where the literature for this article has been reviewed and discussed.
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P. Auinger, B.P. Lanphear, H.J. Kalkwarf, M.E. Mansour, Trends in otitis media among children in the United States. Pediatrics 2003; 112: 514 - 520.
A. Bardach, A. Ciapponi, S. Garcia-Marti, D. Glujovsky, A. Mazzoni, A. Fayad, et al., Epidemiology of acute otitis media in children of Latin America and the Caribbean: a systematic review and meta-analysis. Int J Pediatr Otorhinolaryngol 2011; 75: 1062 - 1070.
E. Roy, K.Z. Hasan, F. Haque, A.K.M. Siddique, R.B. Sack, Acute otitis media during the first two years of life in a rural community in Bangladesh: a prospective cohort study. J Health Popul Nutr 2007; 25: 414 - 421.
L Monasta, L. Ronfani, F. Marchetti, M. Montico, L. Vecchi Brumatti, A. Bavcar, et al., Burden of disease caused by otitis media: systematic review and global estimates. PLoS ONE 2012; 7: e36226.
M. Mahadevan, G. Navarro-Locsin, H.K. Tan, N. Yamanaka, N. Sonsuwan, P.C. Wang, et al., A review of the burden of disease due to otitis media in the Asia- Pacific. Int J Pediatr. Otorhinolaryngol 2012; 76: 623 - 635.
World Health Organization (WHO), 2004. Chronic suppurative otitis media: burden of illness and management options. WHO Library Cataloguing-in-Publication Data, Geneva, Switzerland, 1.
Chandra TJ, Lakshmi Prasanna T, A VEnkateswar rao. A study on isolation and identification of bacteria causing nosocomial infections on mobile phones of health care workers. Calicut Medical Journal 2011; 9(1):e2
Mackie and Mac Cartney Practical medical Microbiology: J.G. Collee, A.G. Fraser, B.P.Marnion, A.Simmons Editors. Tests for the identification of bacteria. 14th edition. Churchill living stone publisher; 1999, P: 131-150.
Bailey and Scott's Diagnostic Microbiology, Karan Fabiano Editor. Laboratory cultivation and isolation of bacteria, methods for bacterial identification. 11th edition. Andrew Allen Publisher 2002. P: 133-167.
Healy GB, Rosbe KW. Otitis media and middle ear effusion, in: snow, Ballenger JJ, editors. Ballenger's otorhinolaryngology head neck surgery. BC Decker inc 2003; 16: 249 - 260.
Hirapure PV and Pote MK. Microbial Profile and Antibiograms of Active Patients of Chronic Suppurative Otitis Media in Latur, Maharashtra, India. International Research Journal of Medical Sciences 2014; 2(5): 6 - 9.
Tesfaye G., Asrat D., Woldeamanuel Y. and Gizaw M., Microbiology of discharging ears in Ethiopia. Asian Pac J Trop Med 2009; 2(1): 60 - 67.
Iseh K.R. and Adegbite T., Pattern and bacteriology of acute suppurative otitis media in Sokoto, Nigeria. Ann Afri Med 2004; 3(4): 164 - 166.
Rajat Prakash, Deepak Juyal, Vikrant Negi, Shekhar Pal, Shamanth Adekhandi, Munesh Sharma, Neelam Sharma. Microbiology of Chronic Suppurative Otitis Media in a Tertiary Care Setup of Uttarakhand State, India. North American Journal of Medical Sciences 2013; 5 (4): 282 - 287.
AK. Ako-Nai, F.A. Oluga, A.O. Onipede, E.A. Adejuyigbe, Y.B. Amusa, The characterization of bacterial isolates from acute otitis media in Ile-Ife, Southwestern. Nigeria, J. Trop. Pediatr 2002; 48: 15 - 23.
EA. Al-Faris, H. Abdulghani, G.J. Mukhdomi, A. Kambal, H.S. Al-Muhaimeed, Microbiology and antimicrobials sensitivity of suppurative otitis media. Saudi Med J 1998; 19: 417 - 422.
M. Guven, Y. Bulut, T. Sezer, I. Aladag, A. Eyibilen, I. Etikan, Bacterial etiology of acute otitis media and clinical efficacy of amoxicillin-clavulanate versus azithromycin. Int. J. Pediatr. Otorhinolaryngol 2006; 70: 915 - 923.
Kumar H, Seth S. Bacterial and fungal study of 100 cases of chronic suppurative otitis media. J Clin Diagn Res 2011; 5: 1224 - 1227.
Y. Ding, Q. Geng, Y. Tao, Y. Lin, Y. Wang, S. Black, et al., Etiology and epidemiology of children with acute otitis media and spontaneous otorrhea in Suzhou, China. Pediatr Infect Dis J 2015; 34: e102 - e106.
KA. Al-Mazrou, A.M. Shibl, W. Kandeil, J.Y. Pircon, C. Marano, A prospective, observational, epidemiological evaluation of the aetiology and antimicrobial susceptibility of acute otitis media in Saudi children younger than 5years of age. J Epidemiol Glob Health 2014; 4: 231 - 238.
T.R. Coker, L.S. Chan, S.J. Newberry, M.A. Limbos, M.J. Suttorp, P.G. Shekelle, et al., Diagnosis, microbial epidemiology, and antibiotic treatment of acute otitis media in children: a systematic review. JAMA 2010; 304: 2161 - 2169.
Radiance Research AcademyInternational Journal of Current Research and Review2231-21960975-5241921EnglishN-0001November30HealthcareGenotypes and Markers of Hepatitis B and Antibodies to Hepatitis C virus in Patients with Chronic Liver Disease in a Tertiary Care Hospital in Puducherry
English4044Isabella PrincessEnglish ShashikalaEnglish Vivian Joseph RatnamEnglish Thomas AlexanderEnglish Prashanth K.English Reba KanungoEnglishBackground: Chronic liver disease leading to cirrhosis, hepatocellular carcinoma or hepatic failure have been associated with Hepatitis B and C virus infections. Detection of various viral markers of Hepatitis B have been reported to be useful tools to assess the progression of disease. In view of chronic liver disease being high in this population, an attempt was made to detect Hepatitis B viral markers and antibodies to Hepatitis C in patients reporting to this hospital.
Methods: Serum samples from a cross section of hundred clinically confirmed cases of chronic liver disease were screened for HBsAg, total anti-HBc, total anti-HBs and HCV Ab. The patients who were positive for HBsAg were further screened for HBeAg, total anti HBe and IgM anti-HBc. Genotyping of Hepatitis B virus was done by nested PCR.
Results: HBsAg positive patients accounted for 10% of the patients admitted to this hospital. HCV antibodies were also seen in 10% of the patients. A single patient tested positive for both HBsAg and HCV antibodies. Anti HBs was present in 11%, total anti HBc was detected in 42% and 87.5% had anti HBe. Two patients had IgM to HBc. Genotype C was detected in all nine HBV DNA positive samples.
Conclusion: Hepatitis B and C markers may be used to detect recent infection, active replication and carriers among cases of chronic liver disease. Genotype C is associated with faster progression to hepatocellular carcinoma, hence there is a need to monitor these patients.
EnglishHepatitis B, Hepatitis B markers, Chronic liver disease, HBV genotypesIntroduction
Hepatitis B and C are associated with chronic hepatitis and are also associated with the development of cirrhosis and chronic liver disease. Various markers have been shown to predict progression to chronicity and other complications.[1]
HBsAg positivity is compatible with acute or chronic HBV infection. If this marker remains positive for more than 6 months, it denotes a chronic HBV infection.[2] Among viral causes of hepatitis, Hepatitis B virus (HBV) is the major cause of chronic hepatitis, cirrhosis and primary liver cell cancer in India. About 50% of chronic liver disease (CLD) is due to HBV and 20% is due to Hepatitis C virus (HCV) infection. About 90% of HBV infected patients who acquire infection during birth are prone to develop chronic liver disease in later stages of life.[1]
Genotypes of HBV has a varied distribution in the world with specific geographic distribution. Certain genotypes are associated with disease severity, outcome as well as response to antiviral therapy. Treatment outcomes can be predicted and response to therapy will vary based on the genotypes detected among these patients.[3] A knowledge of the existing genotype in our locality would greatly influence the course of management in these patients. There is a paucity of data on association of Hepatitis B and C in patients with chronic liver disease. Data is also lacking on predominant genotypes of Hepatitis B. Hence this study was undertaken in this group of patients to document the genotypes.
Methods
This cross sectional study was carried out during the period from October 2013 to April 2015 in a tertiary care centre in Pondicherry. This study was approved by the institute`s research and ethics committees. ( Ref no. IEC: RC/13/62)
Clinical details and laboratory investigations including liver profile, coagulation profile, ultrasound abdomen findings and other investigations were obtained and documented. Following the screening process, samples found to be positive for HBsAg were stored at -70OC for HBV DNA amplification and genotyping.
Enzyme Linked Fluorescent Assay (ELFA) was performed to detect all Hepatitis B markers using commercially available kits (VIDAS Anti-HBs Total Quick, Belgium).
Detection of Genotypes (A-F) of Hepatitis B was done by Nested PCR. Using type specific primers of Hepatitis B genotyping kit provided by Helini Biomolecules, Chennai, viral nucleic acid was extracted according to the manufacturer`s instructions by using 200µl serum sample by column centrifugation method. The extracted nucleic acid was used as template for PCR assay.
Amplification of the target HBV DNA and genotyping was carried out by PCR in Eppendorf Mastercycler Gradient, Germany. The results were recorded on a UVP gel documentation system (UK).
Results
Among hundred patients with chronic liver disease who were screened, 92 (92%) were males and 8 (8%) were females. A majority of 61% patients were middle aged individuals (41 - 60 years). The demographic details and risk factors observed among these patients are listed in Table.1
Fifty percent of patients were positive for one or more markers of hepatitis such as HBsAg, anti HBs, IgG anti HBc, HBeAg, anti HBe, IgM anti HBc or HCV Ab.
Among 100 chronic liver disease patients, 11/100 (11%) patients were positive for anti HBs and 42/100 (42%) patients were positive for IgG anti HBc. Eight chronic liver disease patients (8%) were positive for both anti HBs and IgG anti HBc. Among the 11 patients who were positive for HBsAg, 9/11 (9%) were also positive for IgG anti HBc and none were positive for total anti HBs. Among 100 patients with chronic liver disease, 10/100 (10%) were positive for HBsAg and 10/100 (10%) were positive for antibodies to HCV. Apart from this, one patient tested positive for both HBsAg as well as HCV antibody. The remaining 79/100 (79%) patients were non reactive for both HBsAg and HCV antibodies. (Table.2)
Among eleven HBsAg positive individuals, 2 (18.2%) were positive for HBeAg, 9 (18.8%) were positive for anti HBe and 2 (18.2%) were positive for IgM anti HBc. One patient with IgM anti HBc also tested positive for anti HBe, while another who was IgM anti HBc positive tested positive for HBeAg (Fig.1)
Liver profile of HBV and HCV positive patients were compared using t test and Mann Whitney tests, which did not show any statistically significant difference. (Table.3)
Among the 11 patients who tested positive for HBsAg, DNA was detectable in nine patients (81.8%). Two patients (18.2%) did not have detectable levels of virus in the serum. Genotyping of these nine HBV DNA showed that all the nine patients belonged to Genotype C.
Clinical prognosis and survival rates of patients were estimated using two scoring systems, Child - Pugh score and MELD score.
Discussion
Various factors contribute to the severity of disease progression in Hepatitis B infected individuals. HBsAg prevalence in the general population is estimated to be ranging from 2 to 8 % in India.[4] However, HBV carrier numbers are exponential and is above 50 million, thus constituting the large global pool of chronic HBV infections in East Asia.[4] As India is an intermediate HBV endemic zone, large screening studies of communities are necessary to determine the true burden of HBV infection. Investigations on HBV genotypes will help in understanding the molecular epidemiology of the virus in any given area.
The results of the present study revealed that the majority of chronic liver disease patients (92%) were males due to higher rate of alcohol intake in males. Among these, 9% of males and 1% of females were positive for HBsAg and HCV antibodies were present in 9% males and 1% females. Alcoholics are known to be more susceptible to liver damage due to Hepatitis B and C because ethanol has adverse effects on humoral and cellular immune responses thereby impairing the ability of the host to generate viral specific CD 4 and CD 8 immune responses.[5]
In the present study, prevalence of both HBV and HCV was found to be 11%. A recent study from India by V Singh et al reported higher prevalence of HCV (48%) than HBV (30%) among patients with chronic liver disease. Majority of patients included in this study had cirrhosis of liver and 3% individuals had co infection of HBV and HCV.[6] The co infection rate in the present study is also very negligible (1%).
In the absence of HBsAg and anti HBc, presence of anti HBs indicates protective immunity against HBV acquired by vaccination. Anti HBs was seen in 11% patients indicating immunity to Hepatitis B infection, whereas only 3 patients gave a history of Hepatitis B vaccine. The 89% of patients negative for anti HBs are therefore more susceptible to acquire Hepatitis B infection. Hence it is prudent to advise immunization with Hepatitis B vaccine for chronic liver disease patients.[7,8]
IgG antibodies against HBc was detected in 42/100 (42%) thus denoting past exposure to infection. Among these 42 patients, 9 were positive for HBsAg denoting that they were chronic carriers. However, 24/100 (24%) were negative for HBsAg. Isolated anti-HBc is seen only in two clinical conditions which are occult hepatitis and resolved hepatitis B infection. In patients with occult HBV, anti-HBc is presumed to be the only serological marker to suggest HBV infection. In these patients, there is failure in expression of detectable HBsAg. However the diagnosis of occult hepatitis can be confirmed in these cases only when HBV DNA is detected either in serum or liver tissue.[7,8] In this study, isolated anti-HBc in 24% individuals suggests that these patients might have occult HBV infection.
All patients with antibodies to HBe should also be considered infectious as studies suggest that HBV DNA is present in 26-64% of these patients, suggesting active viral replication.[9] The reason for this condition is the development of pre core mutants, where there is failure to express HBeAg in serum, due to mutation in the basal core promoter region.[6] This was observed among 9 patients where HBeAg was negative but anti HBe was present in the present study. It is highly likely that these 9 patients harboured pre core mutants.
There was no statistically significant difference in prognosis of chronic liver disease in HBV DNA positive and negative patients (p value : 0.709 and 1.000 respectively) by the Child score and MELD scoring systems.
HBV DNA was found in the serum in 81.8% out of eleven HBsAg positive samples. Presence of HBV DNA directly indicates that the virus is replicating; however, the amount of DNA does not correlate directly with the degree of HBV-induced liver disease. Highest levels of HBV DNA are seen in patients who have a positive HBeAg.[10] One reason for undetectable DNA in two of our patients could be that the number of viral copies were less than detection threshold.
The commonest genotypes of HBV reported from India are D,A,C and B in descending order. However there are variations among the various geographical regions, wherein certain places like Vellore report D and C as the commonest. Genotype A has been reported as second commonest genotype after genotype D in many places across India.[11,12] Interestingly genotype B is only reported recently from Hyderabad though they are predominantly reported from far east and South East Asian countries. A recent study from Chennai reported all the four common genotypes in equal number.[13]
All the HBV infected patients in our study were found to have Genotype C. Genotyping of HBV is important in predicting the disease severity and outcome as well as in predicting response to antiviral therapy in patients with chronic HBV infection. HBV genotype C is independently associated with a higher risk of hepatocellular carcinoma and is associated with more rapid progression to cirrhosis than other HBV genotypes.[14,15] One HBV infected patient in our study had an established hepatocellular carcinoma at presentation.
Conclusion
Hepatitis B and C are well known causes of chronic liver disease. We found a dual etiology in 21% patients underlining the importance of screening for multiple etiologies (hepatotropic viruses) in all patients with chronic liver disease. Serological markers of Hepatitis B and C may be used to detect recent infection, active viral replication and carriers among cases of chronic liver disease. Diagnosing the stage of hepatitis in these patients will aid in choice of antiviral therapy. Treating HCV infected patients with conventional and newer antivirals may be considered in order to prevent progressive fibrosis of liver tissue. Genotype C of HBV is associated with faster progression to hepatocellular carcinoma, hence these patients need to be monitored throughout the course of illness. Further genotyping studies should be conducted on a larger population in this geographic area. All chronic liver disease patients need to be vaccinated to prevent HBV infection.
Acknowledgement
Authors acknowledge the immense help received from the scholars whose articles are cited and included in references of this manuscript. The authors are also grateful to authors / editors / publishers of all those articles, journals and books from where the literature for this article has been reviewed and discussed.
Table 1. Demographic characteristics of patients with chronic liver disease (n=100)
Risk factors commonly found in chronic liver disease patients were alcohol, past history of jaundice. Most patients were unimmunized.
Table 2. Distribution of HBV and HCV markers among patients with chronic liver disease (n=100)
Presence of HBsAg and HCV Ab were equal with a co infection of 1%. Markers suggesting past infection, spontaneous clearance were also found.
Table 3. Liver profile of HBV (n=11) and HCV (n=11) infected individuals
Liver enzymes among infected and uninfected patients was not statistically significant
Fig 1. Distribution of HBeAg, anti HBe and IgM anti HBc among HBsAg positive patients with chronic liver disease (n=11)
Most patients (9%) had anti HBe in serum. HBV DNA was also present in the serum probably suggesting presence of pre core mutants.
All the samples in which HBV DNA was detected tested positive for Genotype C.
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Longo, Fauci, Kasper, Hauser, Jameson, Loscalzo. Harrison`s principles of internal medicine, 18`th edition, U.S.A, Mc graw-Hill. 2012;(2):2546.
Krajden M, Mc Nabb G, Petric M. The laboratory diagnosis of hepatitis B virus. Can J Infect Dis Med Microbiol. 2005;16:65-72.
Kao JH, Chen PJ, Lai MY, Chen DS. Genotypes and clinical phenotypes of hepatitis B virus in patients with chronic hepatitis B virus infection. J Clin Microbiol. 2002;40:1207-09.
Datta S. An overview of molecular epidemiology of hepatitis B virus (HBV) in India. Virol J. 2008;5:156.
Spiros P Hiotis, Nuh N Rahbari, Gerald A Villanueva, Eunjie Klegar, Wei Luan, Qin Wang et al, Hepatitis B vs. hepatitis C infection on viral hepatitis-associated hepatocellular carcinoma. BMC Gastroenterology 2012;12:64.
V Singh, R Katyal, RK Kochhar, DK Bhasin, RP Aggarwal. Study of Hepatitis B and C Viral Markers in Patients of Chronic Liver Disease, Indian J Med Microbiol.2004;22:269-70.
Bonino F, Piratvisuth T, Brunetto M, Liaw Y. Diagnostic markers of chronic hepatitis B infection and disease. Antivir Ther. 2010;15:35-44.
Rabbi F, Rezwan M, Shirin T. HBeAg/anti-HBe, alanine aminotransferase and HBV DNA. Bangladesh Med Res Counc Bull.2008;34:39-43.
Alhababi F, Sallam T, Tong C. The significance of 'anti-HBc only' in the clinical virology laboratory. J Clin Virol. 2003;27:162-69.
Bonino F, Hoyer B, Nelson J, Engle R, Verme G, Gerin J. Hepatitis B virus DNA in the sera of HBsAg carriers : a marker of active Hepatitis B virus replication in the liver. Hepatology.1981;1:386-91.
Perumal V, Priya A, Gopalan S, George C, Dolly D, Sukanya R et al. Distribution of Hepatitis B Virus Genotypes in Blood Donors and Chronically Infected Patients in a Tertiary Care Hospital in Southern India. Clin. Infect. Dis.2004;38:81-6
Torbenson M, Thomas D. Occult hepatitis B. Lancet Infect Dis. 2002;2:479-86.
Suneeta K, Anand N, Pallipurath R, Melvin J, Selvaraj V, Girish Kumar, Chethrapilly P. Occurrence of hepatitis B virus genotype B and B +C mixed infections in Chennai, South India. Braz J Infect Dis. 2013;17:615-16.
Sanchez LV, Maldonado M, Bastidas-Ramirez BE, Norder H, Panduro A. Genotypes and S-gene variability of Mexican hepatitis B virus strains. J Med Virol 2002;68:24-32.
Mustafa Sunbul. Hepatitis B virus genotypes: Global distribution and clinical importance. World J Gastroenterol. 2014;20:5427-34.
Radiance Research AcademyInternational Journal of Current Research and Review2231-21960975-5241921EnglishN-0001November30HealthcareOptimization study of sweeteners for preparation of syrup for sugar free Traditional sweet: Gulab jamun
English4553Radha KushwahaEnglish Vinti SinghEnglish Maya PrakashEnglish Devinder KaurEnglishAim: Study was conducted with artificial sweetener based syrups to be used in the preparation of Gulab jamun with an objective to get low calorie foods.
Methods: The sweeteners used in the study were Stevia, Maltitol and Sucralose. For sugar free product the syrup concentration was optimized using response surface methodology. A rotatable central composite design (CCRD) was applied on three controlled variables viz. Maltitol, Stevia and Sucralose. Sweetness, lingering sweetness, color, softness, and textural properties were evaluated by trained sensory panelists using combined methods Quantitative Descriptive Analysis. Texture and taste profile was done by Texture Profile Analyzer and Electronic Tongue respectively.
Results: Threshold values for Stevia, Maltitol and Sucralose were 0.0027, 1.78, and 0.005% respectively. The hardness of fresh Gulab jamun samples ranged from 1.8-3.86N. E-tounge graph shows the variance of 2DFA (DF1 and DF2) in which DF1 ranges from 89.61 -96.54% and DF2 ranged between 3.05-8.83%.
Conclusion: All three responses were significantly (p EnglishGulab jamun, Response surface methodology (RSM), central composite design, Sugar substitute, Quantitative Descriptive AnalysisIntroduction
Sweets plays very important role in our society. Sweets which are made from sugar adds calorie intake of consumer. Additional intake of sweets which are prepared from sugar causes diabetes, it also causes obesity and overweight. Obesity and overweight in people are associated with various risk factors for cardiovascular disease [1, 2]. People suffering from Diabetes are advised to restrict the use of sugars. To avoid these risks nowadays artificial or alternative sweeteners are in use. Use of these artificial sweeteners can help to maintain weight and normal blood glucose level [3]. Sweeteners are not only providing flavor to foods but they can also used to preserve foods, provide body and texture, enhance other flavors and facilitate fermentation process.
Stevia and Sucralose belongs to high intensity sweeteners which added in many food products like diabetic and dietetic baked products, confectionary and dairy based products. Storage studies of artificially sweetened lassi with binary sweeteners found beneficial to consumer choices for low calorie products [4, 5]. Use of low calorie sweeteners in various products sometimes reduces costs and enhances product taste and stability. Polyols/bulk sweeteners can be used alone or with the combination of artificial sweeteners [6]. A large number of sweeteners available, each one can be used in the situations they are best suited for [7]. Sensory analysis could be an important tool in product development. Sensory analysis is an effective way to give accurate quality assessment, but it is also have limitation by various factors such as taste saturation and sweetness differences if any sample has very minute changes. So it is an urgent problem to find a rapid, simple, credible way to determine the sweetness differences among samples [8]. To overcome the above problem Electronic tongue (E-tongue) used, it is a mimic of human taste device and have been fruitfully applied to discriminating different beers, milk [9, 10], fruit juices [9-13]. Keeping significance of these sweeteners in mind, this present work was done to check the texture and overall acceptability of products with blend of sweeteners in Gulab jamun. It is a traditional food prepared by a mixture of khoa and refined wheat flour with baking powder. Response Surface Methodology (RSM) was found to the most effective tool for optimization process and to understand the interaction of various variables and find the optimum concentration of components that affects the responses.
MATERIALS AND METHODS
Materials
Maltitol and Sucralose food grade sample was procured from laboratory of CFTRI, Mysore, Stevia food grade sample was procured from Stevia World Agrotech Pvt, Ltd. Bangalore, Gulab jamun mix of MTR Bangalore, palm oil purchased from local market.
Threshold measurements
Threshold test for the sugar and intense sweeteners were conducted as per the method IS: 5126[14]. This arithmetic series was ranges from 0.1 to .6% for sugar was prepared and tasted by trained panelists. The arithmetic series for sweeteners were ranges from Maltitol (0.15 to 0.9%) Stevia (0.005 to 0.03%) and Sucralose (0.0025 to 0.0125%).
Time-Intensity
This test was performed according to method of Patil et al. [15]. A known concentration of sweeteners were taken for the preparation of syrup solution and presented this set to trained panelists. The panelists were asked to mark the intensity of the perceived sensation on the score card.
Preparation of syrup and Gulab jamun
Sugar syrup was prepared by dissolving 100g sugar in 50 mL of water and then boiled for 5 minutes on medium heat. Optimization of Maltitol syrup, Stevia, and Sucralose as the blend for the preparation of low calorie syrup than sugar syrup are given below in table 1. Weighed the given amount of sweetener in which added 5 ml of water and dissolved properly. Thus for the preparation of syrup all the sweeteners increased 10 times and dissolved in 30 mL of water and boiled for 4-5 minutes on medium heat, and concentration should be 550B [6].
Rheological properties of syrup
Rheological properties of the syrup made by different type of sweeteners were measured by using a Rheaometer (MCR 52, Anton Paar Graz, Australia). For rheological measurement used Measuring plate of PP75 with Rotational tests at controlled shear rate (CSR). All rheological measurements were conducted to duplicate samples [0-200 shear rate (1/s)].
Electronic Tongue analysis of syrup
Electronic Tongue (Auto-sampler, Model: ASTREE, α- M.O.S, Toulose, France) was used for analysis of the syrups to get the pattern matching of sweetness among them. Acquisition Delay 0.0(s); Acquisition time 120(s); Acquisition period 1.0(s); and Stirring rate 1.0 were used for analysis.
Texture analysis of Gulab jamun
The texture properties of the Gulab jamun prepared with different syrup was measured by force in compression using a Texture Analyzer (Model:TA-HDi Texture Analyzer). For the textural analysis 50 mm dia. cylinder aluminum probe was used. The load cell was 50 kg and the crosshead speed was 10mm/min. the peak force which is required to compress Gulab jamun was recorded in Newton's (N).
Sensory analysis
Sensory analysis should be carried out in the sensory booth room consisted of individual booths equipped with fluorescent lights, temperature maintained at 25±20C, and free from noise and odor built as per the standard conditions according to ASTM 1996[16]. The selected panel consisted of 10 judges from Sensory Science department who regularly participated in sensory analysis studies.
Method of scaling
For sensory analysis of product Quantitative descriptive analysis (QDA) method of intensity scaling was followed [17]. This score card consisted of 15 cm QDA scale where in 1.25 cm was showed detection threshold and 13.75 cm saturation threshold. Panel members were asked to mark the perceived intensity of the attribute by drawing a line on the scale.
Statistical analysis and Experimental design
All experiments were conducted in triplicate and the mean were reported. Discriminant function analysis (DFA), optimization design (response surface methodology), generation of response surfaces were created by using statistical software SPSS for identifying attributes causing affect among the samples.
Central composite design
The central composite rotatable design (CCRD), Design Expert version 7.0.0 Stat-Ease, USA was used in designing the experiments. Twenty experiments were carried out according to design with 3 factors 5 levels for each variable. Five levels of variables were applied to study the responses pattern viz., Gulab jamun juiciness, lingering sweetness and overall acceptability on QDA scale. A rotatable central composite design was applied to optimize the syrup formulation (Table 4). The independent variables that were optimized are: Maltitol (X1), Stevia (X2) and Sucralose (X3) (Table 3). Levels of these 3 independent variables were selected on the basis of laboratory trials. The effect of all three independent variables on juiciness, lingering sweetness and overall acceptability were investigated using central composite rotatable design.
Yk= β0 + β1x1 + β2x2+ β3x3 + β11x12 + β22x2 2+ β33x32 + β12x1x2 + β23x2x3 + β13x1x3 (Eq.2)
The predicted values were obtained from the regression equation and analyzed for coefficient of determination (R2), standard error. Analysis of the coefficients of regression models was carried out using analysis of variance (ANOVA) technique to know the significance of each coefficient. The lack of fit was also calculated. Response surface plots were developed using second order polynomial models for all responses keeping the two processing variables at centre point. A second-order polynomial equation was used to fit the experimental data given in Table 4. Different constraints were set for independent and dependent variables along with their relative importance (Table 7). Optimization of the fitted polynomials was done using a desirability function [18]. The optimum condition was verified by conducting experiments at predicted values of variables. Responses were monitored and results were compared with model predictions.
RESULTS
Threshold measurements
The psychometric study showed that the threshold values for Stevia, Maltitol and Sucralose was 0.0027, 1.78, and 0.005% respectively.
Time- intensity profile of Gulab jamun Syrup
Time intensity tests are conducted to recognize the persistence rates of the samples in mouth. Persistence is explained by localized increase in the stimulus concentration in the receptor environment resulting from the ionic surface of proteins in the taste cell membrane [15]. Generally the taste intensity of the compound decreases with time. A 10 second time interval
Rheological properties of syrup
The effects of concentration of sweeteners on rheological properties of syrups are shown in Table 1. There is a significant difference in viscosity of syrups at different concentration of sweeteners .The viscosity of syrup of Gulab jamun was analyzed through 0-200s-1 shear rate. There was gradual decrease with viscosity of all the syrup samples showed with increased shear rate.
Electronic Tongue Analysis
The intensity of sweetness of blend syrup was done by using of e-tongue. Y-axis indicated the voltage difference between the sensor and the reference electrode, and X-axis showed measurement time. DFA pattern showed in the Figure 2 indicates that all samples were different with respect their taste profile as indicated by the clusters formed. The following graph shows the variance of 2DFA (DF1 and DF2) in which DF1 ranges from 89.61-96.54% and DF2 ranged between 3.05-8.83%. It is observed that the distance between all the samples are more thus indicating different taste properties.
Texture Analysis of the Gulab jamun
Texture measurements of all the samples were performed in three replicates and average values were reported with their means and relative standard deviation. Table 2 shows the results obtained. Hardness is the measure of stress required to deform a material. It is the peak force (N) of the first compression of the sample. The hardness values of fresh Gulab jamun samples ranged from 1.84-3.86N.
Sensory analysis of Gulab jamun
The Gulab jamun samples were analyzed for sensory quality in terms of color; syrup sweetness; textural attributes such as softness, mealiness, juiciness and chewiness. Milky aroma and lingering sweetness which is typical of intense sweetness were recorded and based on these impact making attributes the overall quality was assessed. Syrup penetration was found to be adequate in all the blend syrup without any separate core in the centre, but it was the least in Gulab jamun which was prepared with blend 7. Similar trends were observed in juiciness of the samples. Gulab jamun prepared with blend 12 had more lingering sweetness than others.
Response surface methodology
The effect of Maltitol, Stevia and Sucralose on juiciness, lingering sweetness and overall acceptability of Gulab jamun are shown in Table 4. The independent and dependent variables were fitted to the second order model equation and evaluated for the goodness of fit. The lack of fit is a measure of the failure of a model to represent data in the experimental domain at which parts were not included in the regression [19].
Effect on juiciness of Gulab jamun
Response surface plot showing the effects of Maltitol, Stevia and Sucralose on the Gulab jamun juiciness are presented in Figure 4A-C. It was observed from ANOVA data that the model was significant (p Englishhttp://ijcrr.com/abstract.php?article_id=2359http://ijcrr.com/article_html.php?did=2359
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Radiance Research AcademyInternational Journal of Current Research and Review2231-21960975-5241921EnglishN-0001November30HealthcareA Study of Adult Onset Generalized Eruptive Langerhans Cell Histiocytosis with Rare Association of Nail Pterygium
English5457Sunanda MahajanEnglish Vikram LahoriaEnglish Vidya KharkarEnglish Uday KhopkarEnglishBackground: Langerhans cell histiocytosis(LCH) is a rare proliferative disease which generally affects children and rarely, adults. LCH in adults first presenting in the skin is very rare and often it is misdiagnosed as it mimics number of common skin conditions. Nail changes are another cutaneous feature which is not frequently described in adults.
Objectives and Methods: To present two new cases of adult LCH and a review of the literature of generalized cutaneous LCH in adults.
Results: Two adults with widespread papulo-nodular cutaneous eruptions in seborrheic distribution. Both the cases had palmoplantar purpuric papules and involvement of nails with pterygium formation, which is a rare finding not frequently reported in LCH. There was pituitary involvement in the form of diabetes insipidus in both the cases though it was clinically symptomatic in only first case. Diagnosis of both the patients was established on the basis of histopathology and immunohistochemistry.
Conclusions: Extensive cutaneous and nail involvement (nail dystrophy and pterygium) is possible in adult onset LCH. Thus, high index of suspicion is necessary to make the diagnosis.
EnglishAdult onset, Generalised, Pterygium, Langerhan cell histiocytosisIntroduction
Langerhans cell histiocytosis (LCH) is a rare disorder which is characterized by clonal proliferation of dendritic cells and mainly affects children under 10 years of age, although it can occur at any age, it is rarely reported in adults (1). It comprises a wide range of clinical presentations depending upon the organs it affects. The clinical course and prognosis of LCH is diverse which ranges from a spontaneously regressing single lesion to a life-threatening multisystem disease with rapid progression and sometimes even death. In adults, lungs are the most commonly involved system followed by bones and skin (2,3). Cutaneous lesions in LCH can be the great pretender and mimics number of common dermatoses(4) it creates more confusion when it is the presenting feature , which is rarely seen in adults. Nail changes are another cutaneous feature which is not frequently described in adults(9).
Objectives and Methods: Two new cases of adult LCH were studied with their complete workup and a review of the literature of generalized cutaneous LCH in adults.
Results: Two adults presented with widespread papulo-nodular cutaneous eruptions in seborrheic distribution of 2 years and 5 years duration respectively. Both the cases had palmoplantar purpuric papules and involvement of nails with pterygium formation, which is a rare finding not frequently reported in LCH. There was pituitary involvement in the form of diabetes insipidus in both the cases though it was clinically symptomatic in only first case. Diagnosis of both the patients was established on the basis of histopathology and immunohistochemistry.
Case 1
A 22 year old unmarried male presented with sudden onset of skin coloured to red raised itchy lesions over face which progressed gradually to become generalized over the next 2 years which showed ulcerations over the flexures since last 6-8 months. The patient had loss of appetite with recent weight loss (5 kgs in last 6 months) and increase in thirst and frequency of micturition.
Examination revealed multiple erythematous and translucent umbilicated papules coalescing to form plaques intermixed with hemorrhagic papules, crusts and pustules distributed in seborrheic pattern. Dirty greasy scales matted with purulent discharge were seen over the scalp. Both palms and soles showed punctate purpuric micropapules. All twenty nails were dystrophic with erythematous papules and pustules periungually. Two finger nails of left hand showed pterygium (figure 1a and 1b). Papular lesions were seen over the lips and hard palate. Systemic examination was uneventful.
Complete blood counts with biochemical tests were within normal limits. Urine osmolality was low 195 mosm/kg while serum osmolality was slightly high, 303mosm/kg. Water deprivation test was positive indicating central diabetes insipidus. Serum FSH, LH and serum testosterone levels were lower than normal limits.
Biopsy done from one of the papules showed lichenoid infiltrate in upper dermis and infiltrate consisting predominantly of large histiocytes with kidney shaped nucleus with few lymphocytes. The cells stained positively with CD1a and S100 (figure 1c and 1d).
X-ray skull showed enlarged sella turcica which was supported by MRI and CT (plain) scan brain, suggestive of hypophysitis. Bone scan showed no evidence of skeletal involvement.PET scan showed hyper metabolism in the axilla, groin and perianal region with focal hyper metabolism in the spleen.
A final diagnosis of adult onset langerhans cell histiocytosis with pituitary and spleen involvement (multisystem disease with high risk group) was made.
The patient was started on Cytarabine, but showed no improvement after 4 cycles. Hence was switched to Cladiribine chemotherapy, following which significant improvement was seen after 6 cycles. Maintenance therapy was given in the form of 6-mercapto-purine(50mg) daily with methotrexate (25mg) once weekly for 1 month. PET-CT scan done after 11 months of chemotherapy showed no evidence of any metabolically active lesion (figure 1e).
For central diabetes insipidus patient was started with intranasal desmopressin daily at night which has to be maintained lifelong.
Case 2
A 48 year old male patient presented with minimally itchy multiple red raised lesions over legs since 5 years which gradually spread to become generalised over the next 3 years. Examination revealed multiple erythematous papules, pustules and nodules intermixed with umbilicated translucent papules over seborrheic distribution with few of them showing haemorrhagic crusts. Periungual region showed pustules and haemorrhagic crusts with dystrophic nails and toe nails showing pterygium formation. Multiple punctate purpuric papules with pustules and few keratotic papules were seen over soles (figure 2a and 2b). An erosive plaque with a few papules was present over the hard palate. Systemic examination was normal.
Complete blood counts and biochemical tests were within normal limits. Urine osmolality was low, 221mosm/kg while serum osmolality was normal, 289mosm/kg. Water deprivation test was positive indicating central diabetes insipidus, although the patient was asymptomatic. Serum FSH, LH and serum testosterone levels were lower than normal limits.
Biopsy from the papular lesion showed dense and diffuse nodular infiltrate in the dermis consisting of histiocytes having reniform nuclei and abundant cytoplasm with lymphocytes and a few eosinophils. On immunohistochemistry CD 1a and S100 were positive (figure 2c and 2d).
X-ray Skull, X-rays long bones, MRI (Brain), bone scan and PET-CT scan were normal.
The diagnosis of adult onset Langerhans cell histiocytosis with pituitary involvement (multisystem disease low risk group) was established. The patient was started on oral Thalidomide(150mg) per day
Discussion
Langerhans cell histiocytosis (LCH) is characterized by proliferation and infiltration of organs by pathological Langerhans cells. The aetiology and pathogenesis of LCH still remains largely undefined. The clinical manifestations of the disease are largely related to the pattern of infiltration of the organs and organ systems involved which includes bone, skin, hypothalamus, liver, lung and lymph nodes(6). It generally affects children with peak incidence at the age of 1-3 years and annual incidence of 4-5 cases per million. However, adult onset LCH is rare with annual incidence rate of 1-2 cases per million (1).
Although the features of this disease are well described in children, they remain poorly defined in adults, due to the rarity of this condition in adults. Thus the optimal treatment is not yet established (3).
According to the report of the International Registry of the Histiocyte Society on adult LCH (IRHSA), which studied the clinical characteristics of 274 cases across 13 nations, single-system disease accounts for 31.39% while multisystem disease was seen in 68.61%. Most common presenting symptoms were local pain(34%), particularly due to bone involvement, weight loss (11%), and fever (10%). Lung was the most frequently involved organ system followed by bone and then the skin(3).
Langerhans cell histiocytosis (LCH) in adults first presenting in the skin is very rare(5), and often it is misdiagnosed as it mimics number of common skin conditions, as seen in both our patients. The development of systemic findings may occur months to years after the initial presentation of skin manifestations. Both the patients had long standing skin eruptions, 2 years in first case and 5 years in second case before presenting to us. Predominant sites of cutaneous involvement typically include the seborrheic pattern with translucent papules being the typical lesions. These lesions frequently show scaling or crusting (4). Generalised skin eruptions are commonly seen in childhood LCH, but it is rarely seen in adults. However both our patients had extensive skin eruption, which is not yet reported in India to best of our knowledge. Various nail changes are well reported in childhood LCH and are considered as bad prognostic factor (7).It includes paronychia, onycholysis, subungual hyperkeratosis and purpuric striae of the nail bed. However in adults it is rare to observe such nail changes, especially pterygium formation, which is seen in both of our patients. Only one case of adult onset lch with pterygium formation has been reported so far (8).
Originally classified into Hand-Schuller-Christian disease, Letterer-Siwe disease, and Eosinophilic Granuloma, is not used anymore. The current classification which is developed by the Histiocyte Society provides uniform criteria for the diagnosis and clinical evaluation of patients. According to the current classification it is divided into a single system LCH (SS-LCH), in which one of the organs is affected and multisystem LCH (MS-LCH) involving at least two organs. The MS-LCH is subdivided into 'low-risk' and 'high-risk' ones. Low-risk patients have no involvement of 'high-risk' organs (liver, lungs, spleen, hematopoietic cells) (10)
Diabetes insipidus (DI) is one of the most peculiar endocrine complications of LCH that can predate the diagnosis or develop anytime during the course of the disease and is found in up to 30% of patients. The risk of development of diabetes insipidus among adults with LCH is probably equal to or even greater than that of children with LCH. Anterior pituitary dysfunction (APD) is found in up to 20% of patients, almost always with DI (4).
Growth hormone deficiency (GHD) is the most frequent disease-related APD found in up to 50% of patients with DI. While gonadotropin deficiency is the second most common deficiency, presenting with menstrual disturbances in women and decreased libido in men (4).Both our cases had DI with APD, although there was no symptoms of DI in the second case.
Conclusion
These cases illustrate that extensive cutaneous and nail involvement (nail dystrophy and pterygium) is possible in adult onset LCH. Thus, high index of suspicion is necessary to make the diagnosis.
Even though asymptomatic, all patients should undergo a careful multidisciplinary evaluation and periodic follow-up to screen for possible asymptomatic localisation that could warrant prompt treatment and may prevent progression to systemic disease.
Such patients need to be treated at tertiary centre because the management is multidisciplinary which require care of oncologists, dermatologists and endocrinologists
Acknowledgement:
Authors acknowledge the immense help received from the scholars whose articles are cited and included in references of this manuscript. The authors are also grateful to authors / editors / publishers of all those articles, journals and books from where the literature for this article has been reviewed and discussed.
Source of Funding : none
Conflict of interest : none
Englishhttp://ijcrr.com/abstract.php?article_id=2360http://ijcrr.com/article_html.php?did=2360
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Radiance Research AcademyInternational Journal of Current Research and Review2231-21960975-5241921EnglishN-0001November30HealthcareStudy of Various Histopathological Patterns in Prostate Biopsy
English5863Mital YadavEnglish Hemina DesaiEnglish Hansa GoswamiEnglishIntroduction: Diseases of prostate gland are important source of morbidity and mortality in male patients. The spectrum of diseases consists of inflammatory conditions, nodular hyperplasia, malignancy etc. The risk of diseases increases with age. Prostate biopsy is essentially a test which detects cancer and other benign conditions of the prostate in patients who have specific indications for it. Other modalities of diagnosis also have been developed, comprising of radiological modalities and prostatic biomarkers. However, biopsy with histopathological examination is the gold standard for the final diagnosis.
Aims and Objective: To study various histopathological patterns in Transurethral resection of prostate(TURP) and needle biopsy of prostate, including benign prostatic hyperplasia(BPH), prostatitis (identifying type and grade of inflammation),incidental detection of carcinoma prostate and confirmation of diagnosis of clinically suspected carcinoma with application of modified Gleason system for grading.
Materials and Methods: Total 100 cases of prostatic lesions including transurethral resection of prostate(TURP) and needle biopsy were evaluated in this study. The received specimens were fixed in 10% neutral buffered formalin and routine paraffin processing followed by hematoxyline and eosin staining was done. All the specimens were analysed with following parameters: type of specimen, age of patient, histopathological pattern and final diagnosis.
Results: In total 100 cases of present study, the most common age group presenting prostatic lesions was 61-70 years. The youngest patient presenting with prostatic lesion was 45 years age, and oldest was of 85 years of age. In this, various histopathological patterns observed were- Benign prostatic hyperplasia (BPH)in 45%,benign prostatic hyperplasia (BPH)with co-existing chronic prostatitis in 10%, granulomatous prostatitis 1% (single case),acute prostatitis 3% and acute on chronic prostatitis 6%.Less frequent finding were benign prostatic hyperplasia (BPH)with basal cell hyperplasia 1%,benign prostatic hyperplasia (BPH)with squamous metaplasia 2%,benign prostatic hyperplasia (BPH)with clear cell changes 3% and some of biopsy show only stromal tissue with hyperplasia in 4%.We reported 7 cases of adenocarcinoma prostate with application of modified Gleason grading system.
Conclusion: Benign lesions are more common than malignant lesions. Among the histological patterns of prostatic lesions, benign prostatic hyperplasia (BPH)is predominant type. It is necessary to study all prostate biopsy [Transurethral resection of prostate(TURP)and needle] in order to identify premalignant lesions, proliferative activity, and grade of inflammation. Histopathological diagnosis and grading plays a definitive role in the management of prostatic cancer.
EnglishTransurethral resection of prostate (TURP) and Needle biopsy, Benign prostatic hyperplasia(BPH), Prostate CarcinomaIntroduction:
The prostate gland is the pear shaped glandular organ that weighs up to 20 gms1. Prostate is fibromusculoglandular organ encircling the neck of the urinary bladder. The prostate is an exocrine gland and forms a significant component of seminal fluid. Histologically it consists of glands lined by basal cuboidal cells and inner secretory columnar cells (double layered)1. Most patients of benign lesions present with complaints related to micturition and incontinence. Of the diseases which affects the prostate the most frequently encountered in clinical practice are benign prostatic hyperplasia (BPH), prostatic cancer and prostatitis2.
Benign prostatic hyperplasia is an extremely common condition in men over the age of 50 years and shows remarkable racial and geographical variations in incidence and mortality3. The clinical incidence of this disease is only 8% during the 4th decade, but it reaches 50% in the 5th decade and 75%in the 8th decade1.
Benign prostatic hyperplasia (BPH)is not premalignant lesion for the prostatic cancer but it may be related to prostate cancer arising in transition zone (Difenbach et al., 2002)4. Non-specific granulomatous prostatitis is noticed occasionally in prostate specimen. It was first described by Tanner and Mc Donald in 1943, who reported an incidence of 3.3% of granulomatous prostatitis in inflammatory lesions. Recently premalignant lesions have become defined, largely as a result of advances in technology.
Carcinoma of prostate is most common internal malignancy among men in United State and is responsible for 10% of cancer deaths 5.In India, prostate cancers constitute about 5% of all cancers in male5,6. Screening of prostatic lesions constitute prostate specific antigen, digital rectal examination, and transrectal ultrasound, but biopsy remains the gold standard diagnostic tool for final diagnosis. Prior to the PSA era, up to 27% of prostate cancers were detected incidentally at the time of transurethral resection of prostate(TURP)7. The modified Gleason's system appears better to predict progression -free survival after radical prostatectomy than the original Gleason's system did.
Material and methods:
The study was conducted in the Department of Pathology, B.J Medical College, civil hospital - a tertiary level hospital of Ahmedabad. The study period was from April 2017 to June 2017 and prostatic specimen data were collected retrospectively from archives of histopathology register. From April 2017 to June 2017 a total of 100 transurethral resection of prostate(TURP) and needle biopsy were evaluated. The received specimens were fixed in 10% neutral buffered formalin and routine paraffin processing followed by hematoxyline and eosin staining was done. All the specimens were analysed with following parameters: type of specimen, age of patient, histopathological pattern and final diagnosis. The slides were examined under light microscope, and Various histopathological patterns were studied in all cases and were classified with reference to age. Following histopathologic assessment, the tumors were classified according to WHO recommendation, and histologic grading was done using modified Gleason's system.
Result:
In this study a total of 100 prostate specimens were studied which were received between April 2017 to June 2017 in the histopathology section of department of Pathology in B.J. Medical College, Civil hospital, Ahmedabad. Of the 100 specimens 47(47%) were transurethral resection of prostate(TURP)specimens and 53(53%) needle biopsy specimens.
All prostatic specimens were broadly classified into benign 93(93%) and malignant 7(7%)[figure1]. Maximum cases of benign prostatic hyperplasia( BPH )(38) were seen in the 61-70 years age group[Table 1and figure 2]. A glandulostromal pattern of hyperplasia(72%)was the most frequent histological pattern which occurred. Stromal pattern of hyperplasia (4%) was less common.In this 45(45%) were benign prostatic hyperplasia (BPH) only [Figure 3]. Benign prostatic hyperplasia (BPH) with co-existing chronic prostatitis10(10%)[Figure 4], acute on chronic prostatitis 6(6%), acute prostatitis 3(3%)[Figure 5] and granulomatous prostatitis 1(1%)[Table 2]. In this study we reported one (1%) case of granulomatous prostatitis which showed granulomas with giant cells; however, Ziehl Nelsen staining was negative for AFB, and was labeled as non specific.
Less frequent finding was benign prostatic hyperplasia (BPH) with clear cell cribriform hyperplasia 3(3%)[Figure 6], benign prostatic hyperplasia (BPH) with basal cell hyperplasia 1(1%)[figure 7], benign prostatic hyperplasia (BPH) with squamous metaplasia 2(2%)[Figure 8].
We reported 7 cases of adenocarcinoma prostate with modified Gleason score. Histopathology of biopsy received showed single, separate, much more variable glands, closely packed but irregularly separated, ragged and poorly defined edge (Gleason's grade 3)[Figure 9]. Second most predominating pattern is fused glandular, cribriform pattern and hypernephroid (Gleason's grade 4) [Figure 10]. The most common predominant grades observed in this study were grade 3 and grade 4. The most common score obtained was 6 in 4 cases out of the total 7 adenocarcinoma cases.
Discussion:
A retrospective study of 100 cases of prostate biopsy were done, result were noted and comparison with other studies were undertaken as follows:
.
Age:
Lesions of prostate are extremely common over the age of 50 years. The clinical incidence of this disease is only 8% during the 4th decade, but it reaches 50% in the 5th decade and 75%in the 8th decade1. Benign prostatic hyperplasia (BPH)and carcinoma of the prostate are increasingly frequent with advancing age8.
In present study, age group affected with prostatic pathology was 45-85 years. Maximum cases of benign prostatic hyperplasia (BPH) (38) were seen in the 61-70 years age group similar to Matapurkar et al9. Kim KB et al. had more cases(44) in 71-80 age group10. Malignant lesions encountered predominantly in age group 61-70 years that are similar to Sharma et al11.
Benign and malignant:
Benign prostatic hyperplasia (BPH) and adenocarcinoma are the two most common conditions affecting prostate gland.
In present study malignant cases were7 (7%), and benign cases were 93 (93%) with ratio 1:14 approximately. In present study, the predominant lesion was benign prostatic hyperplasia (BPH) (45%) similar to Neha Angurana's12 study (50.5%), followed by benign prostatic hyperplasia (BPH)with prostatitis (21%) and prostate cancer (7%), basal cell hyperplasia and cribriform clear cell hyperplasia was observed.
Microscopy and Histopathological patterns:
Benign prostatic hyperplasia: There is hyperplasia of glandular and stromal tissue with papillary buds, in foldings and cysts. In glandulostromal pattern-Proliferating glands and fibromuscular stroma were assessed to be roughly in equal proportion. While in Stromal pattern- The sections showed more stromal elements than glands or were made up almost entirely of stromal elements.
In present study, glandulostromal pattern of hyperplasia(72%)was the most frequent histological pattern which occurred. Stromal pattern of hyperplasia (4%)was less common .Our study was in agreement with study done by Zeenath Begum, Abdul Hakeem Attar, Mandakini B. Tengli, Mohammed Mateen Ahmed13 (8%) in respect that glandulostromal hyperplasia was most commonly noted.
Prostatitis: It shows inflammatory change with in prostate glands. Acute prostatitis:where there are neutrophils within acini and throughout stroma, intraductal desquamated cellular debris, stromal edema and hyperaemia. Acute prostatitis is rarely seen in surgical specimens. In present study acute prostatitis(3%)was observed. Chronic prostatitis:Chronic prostatitis is more common. Chronic inflammation typically involves the prostate in periglandular distribution and contains an admixture of plasma cells,lymphocytes and histiocytes. In present study Benign prostatic hyperplasia (BPH)with co-existing chronic prostatitis in 10(10%) cases was observed. Chronic prostatitis is most commonly observed in benign prostatic hyperplasia (BPH)which was also observed by Dr. Ashish Joshee, Dr. Kaushal C.L. Sharma (14) in their study14. Malakoplakia:Usually associated with bladder disease, may clinically mimic cancer, resulting in prostatic induration and a hypoechoic lesion seen on transrectal ultrasound. On microscopy it show Marked histiocytic infiltrate containing Michaelis-Gutmann bodies (calcospherites) that may resemble signet ring cells at frozen section15.
Granulomatous prostatitis: Most commonly diagnosed granulomatous process within the prostate is non specific. It is thought to represent an initially immune-mediated process accompanied by a reaction to the prostatic secretions released from obstructed ducts on microscopic examination-large nodular aggregate of histiocytes, epithelioid cells, lymphocytes, and plasma cells. Characteristically, granuloma formation are seen16.
In present study granulomatous prostatitis(1%) was observed. The incidence of non specific granulomatous prostatitis was 0.5% obsereved in Stillwell TJ, Engen DE, Farrow GM17 in their study.
Types of epithelial hyperplasia
Various hyperplastic lesions were observed like papillary, basal, cribriform. basal cell hyperplasia is usually seen in the transitional zone, but it may also occur in the peripheral portion of the gland. Microscopically it appears as small, solid nests of benign-appearing epithelial cells with a somewhat clear cytoplasm1. Cribriform hyperplasia is an uncommon and controversial form of hyperplasia1. In clear cell cribriform hyperplasia, cytoplasm of hyperplastic glandular cells often a clear1.
In present study benign prostatic hyperplasia (BPH)with basal cell hyperplasia 1(1%) and clear cell cribriform hyperplasia 3 (3%)was observed.
Types of metaplasia:
Squamous metaplasia can be seen at the periphery of infarcts, after TUR, as a result of hormonal manipulation, or sometimes with no obvious predisposing cause. In present study benign prostatic hyperplasia (BPH) with squamous metaplasia in 2(2%) cases was observed.
Carcinoma Prostate:
Carcinoma of prostate is the second most common malignancy in men, second only to lung cancers. Hormonal factors play important role in the development of prostatic carcinoma.5-10% of prostatic carcinoma have a genetic link. A higher incidence has been seen in males with a first degree relative being affected1.
Features favoring prostatic carcinoma:
Architectural: Infiltrative patterns, small glands, crowded glands.
Nuclear: Prominent nucleoli, enlargement, hyperchromasia, mitotic figures, apoptotic bodies.
Cytoplasmic:Amphophilic cytoplasm, sharp luminal border18.
In present study carcinoma prostate was identified incidentally in 7 (7%) i.e., 7 of 100 cases, close to previous study by Otto B et al.19where only 1.4% patients were found to have prostate cancer on pathology in prostate biopsy samples. Adenocarcinoma was the only histological type of cancer found in this study Adenocarcinomas were graded according to Gleason's system by taking into account morphological appearance of glandular cells and the glandular pattern. The most common predominant grades observed in this study were grade 3 and grade 4. The most common score obtained was 6 in 4 cases out of 7 adenocarcinoma cases. Vollmer20 had score 6 most common whereas Brawn et al21 had scores 6 and 7 in his study.
Conclusion:
We conclude that prostatic lesions are common in age group of 61-70 years. Benign conditions are more common than malignant conditions Among the histological types of prostatic lesions, benign prostatic hyperplasia (BPH) is predominant type, followed by benign prostatic hyperplasia (BPH) with prostatitis. It is necessary to reassess periodically all prostate biopsies carefully in order to identify premalignant lesions, proliferative activity, grade of inflammation. Efforts should be made to apply modified Gleason's system in case of adenocarcinoma of prostate to improve management .
Table 1: Age-wise distribution of cases:
Age (yr)
Benign,n(%)
Malignant, n(%)
41-50
6
0
51-60
24
1
61-70
38
4
71-80
23
2
81-90
2
0
Total
93
7
Table 2: Distribution of Histopathological Patterns pattern:
Histopathological patterns
No. Of cases
Percentage
Benign prostatic hyperplasia (BPH)alone
45
45%
Benign prostatic hyperplasia (BPH)with chronic prostatitis
10
10%
Benign prostatic hyperplasia (BPH)with acute on chronic prostatitis
6
6%
Granulomatous prostatitis
1
1%
Benign prostatic hyperplasia (BPH)with acute prostatitis
3
3%
Stromal hyperpasia only
4
4%
Benign prostatic hyperplasia (BPH)with Clear cell hyperplasia
3
3%
Benign prostatic hyperplasia (BPH)with basal cell hyperplasia
1
1%
Benign prostatic hyperplasia (BPH)with squamous metaplasia
2
2%
Benign prostatic tissue
18
18%
Adenocarcinoma prostate
7
7%
Total
100
100%
Englishhttp://ijcrr.com/abstract.php?article_id=2361http://ijcrr.com/article_html.php?did=23611. Rosai and ackerman's surgical pathology tenth edition.
2. Cotran RS, Kumar V, Robbins SI. Prostate. In: Cotran RS, Kumar V, Robbins SI (eds): Robbins Pathologic Basis Of Disease, 6th ed., Philadelphia: Saunders Co., pp. 1025-1034, 1994
3. Walsh Pc. Benign prostatic hyperplasia. In: Walsh Pc, Gittes RF, Perlmatter AD, Stamey TA (eds) : Campbell's Urology 5th ed., vol.2, Philadelphia : W.B. Saunders co., pp. 1248-1265, 1986
4.Difenbach MA, Dorsey J, Uzzo RG, Hanks GE, Greenberg RE and Horwitz E et al., (2002). Decision making strategies for patients with localized prostate cancer, Seminars in Urologic Oncology 20 52-62. Egevad L,
5. Consolidated Report of Population Based Cancer Registries 2001-2004:
Incidence and Distribution of Cancer. Bangalore (IND): Coordinating
Unit, National Cancer Registry Programme, Indian Council of
Medical Research; 2006.
6. Garg M, Kaur G, Malhotra V, Garg R. Histopathological spectrum of 364 prostatic specimens including immunohiostochemistry with special reference to grey zone lesions. Prostate Int 2013; vol 1 (4) : 146-151.
7. B. Tombal, L. de Visccher, J. P. Cosyn et al., Assessing the risk of unsuspected prostate cancer in patient with Benign Prostatic hypertrophy : a 13 years retrospective study of incidence and natural history of T1a-T1b Prostate cancers, BJU International, Vol. 84, no. p. 1015-1020, 1999.
8. A Josephine - ?2014, clinicopathological study of prostate biopsy, 2014 Journal of Clinical and Diagnostic Research.
9. Matapurkar BG, Taneja OP. Incidence of carcinoma prostate. Ind J of Cancer 1969 Sept 172-182.
10. Kim KB, Kim KS. A Histopathological observation on 48 cases of benign prostatic hypertrophy. Korean J Urol 1982; 23(8):30.
11. Sharma GC, Mathur SC, Sharma ML. Occult carcinoma in benign hypertrophy of prostate (Clinicopathological study of 100 cases). Ind J Surg 1972 April: 152-155
12. Neha angurana, pattern of prostrate diseases- a histopathological study in Jammu, international journal of basic and applied medical sciences issn: 2277-2103 (online)
13. Zeenath Begum, Abdul Hakeem Attar, Mandakini B. Tengli, Mohammed Mateen Ahmed , Study of Various Histopathological Patterns in Turp Specimens and Incidental Detection of Carcinoma Prostate, Indian Journal of Pathology and Oncology, October - December 2015;2(4);303-308
14. Dr. Ashish Joshee, Dr. Kaushal C.L. Sharma; The histomorphological study of prostate lesions, IOSR Journal of Dental and Medical Sciences (IOSR-JDMS) e-ISSN:
15.Wagner D, Joseph J, Huang J, Xu H. Malakoplakia of prostate on needle core biopsy,a case report and review of the literature.s
16.Oppenheimer JR, Kahane, Epstein JI. Granulomatous prostatitis on needle biopsy, Arch pathol Lab Med 1997.
17.Stillwell TJ, Engen DE, Farrow GM. The clinical spectrum of granulomatous prostatitis: A report of 200cases.J Urol.1987;138:320-323.
18.Epstein, George J, Netto. Biopsy interpretation of the prostate, Forth edition.
19. Otto B et al. incidental prostate cancer in Transurethral Resection of the Prostate Specimen in moderate era. Advances in Urology 2014 ;4:1-4
20.Vollmer RT. Prostatic cancer and chip specimen: complete versus partial sampling. Hum Pathol 1986; 17:285-290. 18. Otto B et al. incidental prostate cancer in Transurethral Resection of the Prostate Specimen in moderate era. Advances in Urology 2014 ;4:1-4.
21. Brawn PN, Ayala AG, vonEschenbach AC, Hussey DH, Johnson DE. Histologic grading study of prostate adenocarcinoma: The development of a new system and comparison with other methods- A preliminary study. Cancer 1982; 49:525-532.
Radiance Research AcademyInternational Journal of Current Research and Review2231-21960975-5241921EnglishN-0001November30HealthcareA Review on Biochemical Aspects of Schizophrenia
English6467Padmanabhan P.EnglishSchizophrenia is a severe disorder affecting the brain. Defective neurotransmitters and altered neurotransmission system maybe one of the various causes for this psychiatric disease. There are several hypotheses explaining the development of schizophrenia. However, recently the role of oxidative stress and inflammation causing some irreversible alterations in the brain tissue are an explanation to the development of schizophrenia.
Oxidative stress is a condition caused due to imbalance between the excessively produced free radicals and antioxidant system of the body. The brain is vulnerable to the damage caused by oxidative stress indicated by elevated levels of biomarkers of oxidative stress. There are research studies confirming the undoubted effects of antipsychotics treatment on the oxidative stress prevalent in schizophrenic patients.
The interplay of cytokines, interleukins and T-cells in inflammation causes development of elevated levels of free radicals which are potentially toxic to the neurons. Thus increased oxidative stress triggers inflammation whereas redox balance causes inhibition of cellular response. The brain is protected form toxic free radicals by the inherent antioxidant defense mechanism.
The current therapeutic modality suggests the synergistic action of omega -3- fatty acids intake in the diet as well as regular doses of antipsychotics taken in combination as a treatment of Schizophrenia. The omega -3-fatty acids affects and elevates the antioxidant defense mechanisms in schizophrenic patients. This will improve the schizophrenic disease condition, status and further prognosis.
EnglishBrain, Oxidative stress, Inflammation, Omega -3- fatty acids, AntioxidantsIntroduction:
Schizophrenia is a severe mental disorder characterized by disordered thoughts, perceptions, emotions and behavior (1). World wide prevalence of schizophrenia is 3.8% to 8.4% according to World Health Organization (2).The symptoms of the psychiatric disease can be described as positive symptoms (e.g. delusions and hallucinations), negative symptoms (e.g. lack of motivation, asociality and blunt emotional response) and cognitive deficits(3). Defective neurotransmitters and altered neurotransmission systems are cited as a cause for schizophrenia (4).
Biomarkers that aid in understanding complex psychiatric disorder like schizophrenia are measured or estimated from post-mortem brain or using in-vivo neuroimaging studies, peripheral biomolecules (e.g. hormones, neurotransmitters or cytokines) and easily available body fluids such as plasma /serum, urine or cerebrospinal fluid (5).
The earliest hypothesis regarding the development of schizophrenia describes disturbances in dopamine metabolism. In addition, recognition that glutamate (N-methyl-D-aspartate-receptors) and gammaaminobutyric acid (GABA) have roles in pathogenesis was cited. Later, the hypothesis that the development of disturbances in some brain areas in schizophrenics supported by neurocognitive impairments in brain due to deterioration in nerve tissue of the brain and gradual progressive disintegration due to alterations in gray matter, occurring in initial period of development during childbirth and adolescence were cited as reasons. Recently, however the role of inflammatory process and oxidative stress causing alterations of brain tissue some of which are irreversible are an explanation to schizophrenia development (6).
Oxidative Stress and Schizophrenia:
Oxidative Stress is a conditions arising due to excess formation of highly reactive molecules of reactive oxygen species (ROS) and reactive nitrogen species (RNS) resultant of imbalance between the toxic reactive oxygen species and the antioxidant system of the body. This condition leads to tissue damage affecting lipids, proteins and DNA. The antioxidant defense system consists of enzymatic antioxidant system e.g. superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) and non-enzymatic antioxidant systems e.g. vitamins A, C, E, glutathione, uric acid, albumin, bilirubin (1).
Various organs of the human body have different susceptibility to oxidative stress. The brain constitutes 2% of the body weight and utilizes 20% of the oxygen, is the most vulnerable to oxidative damage. The reasons being that brain tissue has increased oxygen utilization, is rich in phospholipids, polyunsaturated fatty acids, transitional metal ions (Cu+ and Fe2+) whereas low in antioxidant levels. (1)(7) The oxidative damage of the phospholipids, DNA and protein contents of the neurons in brain alters their functions such as membrane transport, loss of mitochondrial energy produced, genes expressed, receptors and phospholipids -dependent signal transduction may provide explanation to the altered information processing by the brain in schizophrenia (8).
Several research studies have indicated that the biomarkers of oxidative stress such as Thiobarbituric acid reactive substances (TBARS), malondialdehyde (MDA) and 4-hydroxynonenal show increase in activities in the serum of schizophrenic patients in untreated as well as treated patients depicting strong links between oxidative stress and pathophysiology of schizophrenia (7).
Treatment with antipsychotics has an influence on oxidative stress in the course of schizophrenia due to changes in oxidation -reduction balance. Although, there are some studies contradicting this fact the overall undoubted effect of treatment with antipsychotics on the oxidative stress is confirmed in schizophrenia (6).
Inflammatory Response Induces Oxidative Stress in Schizophrenia:
Increased maternal immune system infection may develop the risk of schizophrenia in offsprings. Maternally infected cells may cause increased production of inflammatory cytokines that cross the placenta and result in increase interleukin (IL ) 1 β,IL-6,Tumour necrosis factor (TNF-α) and Interferon (IFN -β) etc by fetal cells. Increased cytokines especially interferon-β also cause DNA fragmentation resulting in free radical production. The free radicals cause damage on nuclear and mitochondrial DNA changes in the neurons which is elevated due top high neuronal high energy consumption rate and lack of cell turnover. This leads to progressive development of pathological features and clinical symptoms associated with schizophrenia. Inflammatory responses induced by pro-inflammatory T cells produce free radicals with an ability to modify proteins, lipids and nucleic acids that are potentially toxic for the neurons. Research work indicates T-cell dysfunction, decreased activation of helper T-cells in both treated and untreated schizophrenic patients as compared to healthy controls. Further, detailed genetic studies based on microarray analysis of differentially expressed genes in isolated T-cells from schizophrenic patients and controls which are indicated by transcript changes pertaining to cell cycle machinery, intracellular signaling, metabolism and oxidative stress. This suggests that altered T-cell response may correspond with oxidative stress in some patients suffering from schizophrenia (3).
Oxidative stress and inflammation are related processes. Chronic inflammation is associated with elevated reactive oxygen species levels and anti-inflammatory cascades are associated with reactive oxygen species concentrations in schizophrenia. Increased oxidative stress triggers inflammation whereas redox balance causes inhibition of the cellular response. In degenerative disease like schizophrenia both oxidative stress and inflammation may be cited as etiologic factors leading to pathogenic consequences (9).
Antioxidant Systems in Brain
Brain is protected from toxicity of reactive oxygen species (ROS) and reactive nitrogen species (RNS) by either
removal of ROS/RNS
inhibit formation of ROS/RNS
binding metal ions needed for catalysis reaction required for ROS/RNS generation.
Glutathione peroxidase (GSH-Px) and glutathione reductase (GR) are well known intracellular antioxidant enzymes. Conversion of peroxides and hydroxyl radicals into non-toxic forms is facilitated by conversion of reduced glutathione (GSH) into oxidized state of glutathione disulfide (GSSG) carried out by glutathione peroxidase. Glutathione reductase recycles GSSG again back to GSH (3) .Superoxide dismutase (SOD) catalyzes the conversion of superoxide radicals to hydrogen peroxide, which is further converted into water by glutathione peroxidase and catalase (7).
Additionally, glutathione -S- transferase and glucose-6- phosphate dehydrogenase detoxifies ROS by decreasing peroxide levels and maintains levels of co-enzymes like glutathione (GSH) and nicotinamide adenine dinucleotide phosphate necessary for primary antioxidant enzymes. Similarly, thioredoxin and thioredoxin reductase maintains the level of antioxidant molecules for e.g. ubiquinone, lipoic acid, ascorbic acid (vitamin C) capable of counteracting ROS/RNS. Other antioxidant defense mechanisms include α-tocopherol (Vitamin E), bilirubin, albumin, uric acid, niacin, carotenoids and flavonoids (3).
In the case of the antioxidants of schizophrenic patients contrasting research studies results are obtained due to differences in species e.g. rats and humans , different tissues e.g. brain and serum, therapeutic features and duration of the disease. In schizophrenic patients it should be noted that there are differences between untreated and treated also the oxidative stress status of patients should be taken into consideration and whether treated with anti-psychotics typical or atypical in nature (7).
Current Therapeutic Modalities:
The dietary intake of essential polyunsaturated fatty acids is suggested considering the dysfunction of membrane phospholipids metabolism in all the cells of the body from the onset of psychosis in patients with schizophrenia .Reduced levels of membrane essential polyunsaturated fatty acids e.g. arachidonic acid, eicosapentanoic acid, docosapentaenoic acid or docosahexaenoic acid and their role in psychopathology of schizophrenia have been reported in treated and untreated patients even after the first episode of psychosis. The membrane phospholipids have an important role in membrane receptor-mediated signal transduction of several neuro-transmitters and growth factors contributing to abnormal information processing in schizophrenia. A combination of eicosapentanoic /docosahexaenoic acid or omega -3- polyunsaturated fatty acids and antioxidant vitamins like C and E causes significant reduction of psychopathology of schizophrenia. This is an indication that essential polyunsaturated fatty acids supplementation could be an effective treatment to cause improvement for the outcome of the disease over an extended period of time (7).
Therapy of utilizing antioxidants have the potential to delay or decrease many psychiatric disorders like schizophrenia. Treatment with N-acetylcysteine (NAC) a rate limiting factor in the synthesis of glutathione (GSH) has been reported to improve the core symptoms of Schizophrenia. The NAC treatment increased glutathione (GSH) levels restoring its levels and improving N-methyl-D-aspartate receptor function implicated by auditory response of brain in research studies (3).
Fish oil (long -chain omega -3- polyunsaturated fatty acids -PUFA's) is a commonly used supplement in the general population with the aim of preventing oxidative stress. Recent study reported that supplementation with fish oil significantly reduced the progression to first episode psychosis (FEP) in schizophrenic patients. This study proves that oxidative stress may prove to be a biomarker of schizophrenia risk and therefore has response to antioxidant treatment (10).Omega -3- fatty acids elevates the antioxidant enzymes and reduces oxidative stress in the brain and possesses synergistic action with anti-psychotic medicine and improved schizophrenic symptoms. This synergistic action of antioxidants certainly plays a therapeutic role and suggests a possible new schizophrenic treatment strategy (1). This also emphasizes the possible importance of dietary nutrient antioxidant supplementation to enhance the antioxidant defense system in body in schizophrenic patients (7).
Conclusion:
Oxidative stress appears to be the key component in schizophrenic patho-physiology. The oxidative stress contributes to be a central point among the other factors which interact to cause the psychiatric disease schizophrenia. The combination of supplements of antioxidant treatment as well as dosages of regular treatment of antipsychotics will support the endogenous antioxidant system and will synergistically improve the schizophrenic disease condition, status and further prognosis.
Acknowledgements: Author acknowledges the immense help received from the scholars whose articles are cited and included in references of this manuscript. The author is also grateful to authors/editors/publishers of all those articles, journals and books from where the literature for this article has been reviewed and discussed.
Source of Funding: None
Conflict of Interest: None
TABLE1: Antioxidant System of Brain
Enzymatic Antioxidants
Non Enzymatic Antioxidants
Glutathione peroxidase (GPx)
Vitamin C (Ascorbic acid)
Glutathione reductase (GR)
VitaminE ( α -tocopherol)
Superoxide dismutase(SOD)
Bilirubin
Catalase (CAT)
Albumin
Uric acid
Niacin
Carotenoids
Flavonoids
Lipoic acid
Thioredoxin
Englishhttp://ijcrr.com/abstract.php?article_id=2362http://ijcrr.com/article_html.php?did=23621. Huang D, Liu S. Oxidative Stress and Schizophrenia. Journal of Psychiatry and Brain Science, 2017, 2(2): 1-5.
2. El- Tallawy HN, Saleem TH, El-Ebidi AMAA, Hasan MH, Gabra RH, Farghaly WMA, El- Maali NA, Sherkawy HS. Clinical and biochemical study of D-serine metabolism among schizophrenic patients. Neuropsychiatric Disease and Treatment, 2017, 13: 1057-1063.
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4. Gaur N ,Gautam S, Gaur M, Sharma P, Dadheech G, Mishra S. The Biochemical Womb of Schizophrenia: A Review. Indian Journal of Clinical Biochemistry, 2008, 23 (4): 307-327.
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6. Nasyrova RF, Ivaschenko DV, Ivanov MV, Neznanov NG. Role of nitric oxide and related molecules in schizophrenic pathogenesis: biochemical, genetic and clinical aspects. Frontiers in Physiology, 2015, 6: Article 139: 1-15.
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8. Pavlovi? D, Tamburi? V, Stojanovi? I, Koci? G, Jevtovi? T, Dordevi? V. Oxidative Stress a Marker of Positive Symptoms in Schizophrenia. Facta Universitatis Series: Medicine and Biology, 2002, 9(2):157-161.
9. Yegin A, Ay N, Aydin O, Yargici N, Eren E, Yilmaz N. Increased oxidant stress and inflammation in patients with chronic schizophrenia. International Journal of Clinical Medicine, 2012,3: 368-376.
10. Flatow J, Buckley P, Miller BJ. Meta -Analysis of Oxidative Stress in Schizophrenia. Biol Psychiatry, 2013, 74:400-409.