PURSE 2011
Permanent URI for this collectionhttps://ir.lib.pdn.ac.lk/handle/20.500.14444/58
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Item type: Item , Chirality dependence of elastic properties of supercarbon nanotubes(University of Peradeniya, 2011-11-24) Gunatilake, P. A. G.; Herath, S. R.Carbon nanomaterials are studied extensively among many nanoscale materials investigated during the last decade. Carbon nanotubes (CNT's) are linear fullerenes which can have aspect ratios as large as 103 to 105 . After the discovery of Y branching of CNT's, attention now is on the hierarchical structures (Supercarbon structures) which can be made of Single Walled Carbon Nanotubes (SWCNT's). When SWCNT's are arranged to form a higher order structure, it is called a supercarbon nanostructure. The present study focuses on the versatile elastic properties of Supercarbon nanotubes (SCNT's) which can be mastered by changing various parameters such as geometry and chirality of constituent SWCNT's and the chiral index of the SCNT. A simple mechanics model is used to estimate the stiffness of these supercarbon nanotubes and the results agree well with previous studies on these structures using molecular dynamics modelling. It was found that in super carbon nanotubes with Y junctions, the length of the constituent SWCNT and its chirality, influence the elastic modulus, stiffness and its ultimate tensile strength. Further the study shows that the higher the length of SWCNT the lesser the elastic modulus. It was also seen that for a given length, Lo ,and diameter, d, of SWCNT, the elastic modulus of the super nanotube turns out to be the same for both armchair and zigzag SWCNTs. By manipulating atoms to form different structures, it is possible to obtain different geometries of nano-structured materials. These new materials can be mastered to have desired material properties in any range. Therefore, these can be used to make bullet-proof clothes and vehicles, high-strength composite materials, nano electromechanical devices (NEMS) etc. At the same time, these low density, flexible materials can be used in light weight composite structures.Item type: Item , Chitosan based nano-carrier system for controlled release of Ascorbic Acid(University of Peradeniya, 2011-11-24) Menikarachchi, M. A. S. K.; Karunaratne, N.; Karunaratne, V.There is an increasing interest in the development of new delivery systems for the controlled release of drugs and bioactive agents. Among these delivery systems, encapsulation of the drugs using a biodegradable matrix shows a promising pathway for the enhancement of the bioavailability of the drugs. The aim of the present study was to produce a chitosan-based nano-carrier system and check the release properties of the entrapped drug comparatively to the release of the free drug, to ensure whether there is a controlled release property in the nano-carrier system. Chitosan is a non-toxic, biodegradable and bio compatible polymer with interesting biological and chemical properties. Ascorbic acid (Vitamin C) was used as a model drug for the process. Ascorbic acid trapped lysosomes were coated with chitosan, with the aid of Tween 80 and sodium sulphate. The chemical structure was analyzed by FTIR and controlled release of ascorbic acid from encapsulated particles over seven hours shows a distinguishable enhancement comparable to free ascorbic acid release.Item type: Item , Chronic prostatitis: symptomatology and the impact on the quality of life in a Sri Lankan population(University of Peradeniya, 2011-11-24) Pethiyagoda, A. U. B.; Priyadarshanl, R. M. S.; Bandara, H. G. W. A. P. L.; Weragoda, W. A. R. V.Chronic prostatitis (CP) or Chronic Pelvic Pain Syndrome (CPPS) affects men in all ethnic origins where they experience considerable morbidity and may remain symptomatic for years as there is limited understanding of the pathophysiology and the optimal treatment.The data regarding Sri Lankan patients remain sparse. The objective of this study was study the symptomatology associated with CP/CPPS in a Sri Lankan population and to evaluate its impact on their quality of life (QOL). A descriptive cross sectional study was conducted in the surgical unit and Genito-Urology clinic in Teaching Hospital Peradeniya from March 2010 to August 2011. The study group included all patients who were clinically diagnosed with CP/CPPS according to the National Institutes of Health (NIH) definition. Symptomatology and QOL were evaluated with NIH Chronic Prostatitis Symptom Index (NIH-CPSI), a nine-item tool with 4 subscores and a total score ranging from 0-43 points, and with higher scores indicating more severe symptoms. The study group included 43 subjects with a mean age of 36.3 (SD=12.21) years with an age range of 18-65 years. The duration of symptoms at presentation ranged from 3 months to 7 years. The commonest presentations were pelvic pain (n=43) involving suprapubic area, urethra or testicles and urinary symptoms (n=38) includ.ing dysuria, frequency and poor emptying. Of the total study group 44.18% (n=19) experienced post ejaculatory pain. NIH-CPSI indicated that except 4. others had experienced pelvic pain commonly in suprapubic area (n=34) during the week prior to assessment while n=35 had dysuria and n=15 had post ejaculatory pain. The average pain was 8.95 measured on visual analogues scale. Most had poor emptying (n=30) and frequency (n=33) as urinary symptoms. Symptoms of 88.37% of patients (n=38) had interfered their usual activities. QOL was affected in all except one. Among affected. most '(n=20) were unhappy to spend the rest of life with their symptoms and n=18 had mixed feeling about it. The Pain score ranged from 0-17 while the urinary symptom score, QOL Impact, Symptom Scale Score and Total score displayed a range of 0-10,0-12,0-27 and 0-37 respectively. Of the study population 55.81% (n=24) had symptoms of moderate severity while 27.9% (n= 12) had severe symptoms. Pelvic pain, urinary symptoms and post ejaculatory pain are the commonest symptoms among local patients with CP who show a broad age range. The symptoms display a wide range of degree of severity and it affects the QOL in 97.67%. Further extensive research are required regarding Sri Lankan patients.Item type: Item , Classical Athenian family in the limelight: was there affection between Athenian spouses?(University of Peradeniya, 2011-11-24) Wickramasinghe, C. S. M.The objective of the study is to re-examine the literary evidence in par with the vase paintings that show scenes from domestic settings in order to perceive whether any affection existed among Athenian spouses because the interpretations given with regard to some such domestic settings seem problematic. The generally accepted view based on the conceptions of the authors of normative texts is that the Athenians considered their wives only as a machine which produce legitimate children and they looked for courtesans, prostitutes and hetaerae (respectable courtesans) for entertainment and that they bore no sentiments of affection for their spouses. Many paintings on Attic red and black figure vases are interpreted and explained following such perceptions. Yet, information from literary sources, more precisely those from Athenian drama and law court speeches infer that the condition of Athenian families was flat as stern and cold as preached and promoted by normative writers such as Plato and Aristotle. This idea is further confirmed through many domestic scenes depicted in Athenian vases such as the domestic scene shown on the Harvard hydria. The scene on it can be interpreted as demonstrating a nucleus of an Athenian family comprising a mother, father and child (with a maid). Not everyone was ready to accept this point of view, probably, when looking at the youth with restrained thoughts of Plato, Aristotle and Xenophon, who describe the husband or the groom as twice as old as the bride which easily fits with the cold relationships they instilled into their relationships when they further asserted that the husbands spent more time outside their homes perhaps in the agora or gymnasium with their peers and not with the family at home. Yet, information from Athenian dramatists and orators pile up in favour of warm affection between spouses. The insight we are provided with through a meticulous study of our literary sources and vase paintings is that there were positive sentiments such as warm affection between Athenian spouses as in any other normal society in antiquity or in our era. This cold and negative picture on the relationship between Athenian spouses has resulted from taking the perceptions of authors of normative texts, whose intention was to present the ideal picture they expected of their society but not the real scenario, as the ultimate characteristic of the Athenian society.Item type: Item , Agricultural risk factors of chronic kidney disease of unknown aetiology in North Central region of Sri Lanka(University of Peradeniya, 2011-11-24) Jayasekara, J. M. K. B; Dissanayake, D. M; Gunaratna, M. D. N; Thilakarathna, S; Sivakanesan, RHealth professionals inSri Lanka havenoticed ahigh incidence of anewformof chronic kid!leydisease of unknown aetiology (CKO-U) infarmers ofNorthCentral Region (NCR). neaimof thestudywas to identify the risk factors related to farming inorder to implement oreventive strategies. Potential agricultural risk factors and other information were collected through interviewer-administered questionnaires given to 315 CKO-U patients anI 321 healthy controls that were randomly selected. The relative risk of each factor was cornpared in terms ofOdds ratios (ORs) and95%confidence interval (CI) by applying th.. linear logisticmodel. In-olvernent In paddy farming activities (OR = 1.945. 95%CI: 1.256-3.010) usage of aqro-chemicals (OR=2.034, 95%CI: 1297-3.190), poor preventive measures when usin.. agro-chemicals (OR = 2845. 95% CI. 1788-4527), high operated paddy extent WithJutexchange of labour (OR= 4734, 95%CI: 2.586-8.665) were identified as significant ·;ontributory risk factors forCKO-U (p<0.005). Cultivating a large landextent without hiri 19 labour was asignificant risk factor for thedisease (p<005) Furthermore. cultivating ·.maller landextent without hired labour (OR= 1558,95% CI .047-1.56) had higher risk thancultivating larger landextent with hired labour (OR= 140. 95%CI: 042142j Inatdition to the agricultural activities. being amale. age> 60 years. smoking. alcoholism. family history of CKO-U. history ofmalaria and snake bites (p<0.05) were identified a;other contributory factors. It ere IS a strong occupational risk factor in the pathogenesis of the disease where the 11alefarmers of >60 of age were at a high risk probably due to long term exposure t,) the aetiotoqical agents (risk factors) Agricultural activities involvinq intense physical acivity were related toCKO-U Further studies are indicated to identify theeffect of dehydraion and physical exertion on the renal functions of these individuals. Poor preventive measures inagrochemical usage related to thedisease indicate the need to educate th{ farmers onsafeagrochemical usage.