Hewageegana P.,University of Kelaniya
Progress in Electromagnetics Research Letters | Year: 2013
We develop a method for calculating transverse static polarizability (per unit length) of a bulk nanowire by taking in to account the temporal and spatial dispersion. To describe these phenomena, we developed analytical theory based on local randomphase approximation and plasmon pole approximation. Our theory is very general in the sense that it can be applied to any material which can be characterized by a bulk dielectric function of the form ε(ω, k). The theory is applied to calculate the transverse static polarizability of dielectric nanowire.
Rajindrajith S.,University of Kelaniya |
Devanarayana N.M.,University of Kelaniya
Journal of Neurogastroenterology and Motility | Year: 2012
Background/Aims: This study was conducted with objectives of assessing subtypes of irritable bowel syndrome (IBS) in children aged 10-16 years, their symptomatology and gender differences. Methods: For this survey, 107 children who fulfilled Rome III criteria for IBS and 1,610 healthy controls were recruited from 8 randomly selected schools, in 4 provinces in Sri Lanka. Data was collected using a previously validated, self administered questionnaire. Results: Constipation predominant, diarrhea predominant and mixed type IBS were almost equally distributed (27%-28%), while unsubtyped IBS had a lower prevalence (17.8%). IBS was more common in girls (59.8% vs 40.2% in boys, P = 0.001). Bloating, flatulence, burping, headache and limb pain were significantly higher in affected children (P < 0.05). Conclusions: This study highlights the distribution of IBS subtypes among Sri Lankan children and adolescents and its female preponderance. This study also shows a higher prevalence of other intestinal-related and extraintestinal somatic symptoms among affected children. © 2012 The Korean Society of Neurogastroenterology and Motility.
Wijesundera R.P.,University of Kelaniya
Semiconductor Science and Technology | Year: 2010
Thin films of n-type cuprous oxide (Cu2O) were potentiostatically electrodeposited on a Ti substrate in an acetate bath. Cu2O thin films were annealed at 500 °C for 30 min in air for growing p-type cupric oxide (CuO) thin films. n-Cu2O thin films were potentiostatically electrodeposited in an acetate bath on Ti/CuO electrodes in order to fabricate the p-CuO/n-Cu2O heterojunction. The structural, morphological and optoelectronic properties of the CuO/Cu2O heterojunction were studied using x-ray diffraction (XRD), scanning electron micrographs (SEMs) and dark and light current-voltage characteristics. XRD and SEM reveal that well-covered single phase polycrystalline Cu2O thin film on the Ti/CuO electrode can be possible at the deposition potential of -550 mV versus the saturated calomel electrode (SCE) in an acetate bath. Photovoltaic characteristics further established the formation of the CuO/Cu2O heterojunction. © 2010 IOP Publishing Ltd.
Rajindrajith S.,University of Kelaniya |
Devanarayana N.M.,University of Kelaniya |
Benninga M.A.,Emma Childrens Hospital
Alimentary Pharmacology and Therapeutics | Year: 2013
Background Faecal incontinence (FI) in children is a significant gastrointestinal problem, with great personal and social impacts. It is characterised by recurrent loss of faecal matter into the underwear. Both functional and organic causes contribute to its aetiology with the former predominating. Aim To review the epidemiology, pathophysiology, clinical evaluation and management of functional faecal incontinence in children. Methods A PubMed search was conducted using search terms f(a)ecal incontinence, and encopresis. Articles on epidemiology, pathophysiology, clinical evaluation, investigation and management of functional FI in children were retrieved and assessed. Results Community prevalence of this distressing problem ranges from 0.8% to 7.8% globally. Male: female ratio varies from 3:1 to 6:1. The diagnosis of FI is often based on established clinical criteria. The majority (82%) have constipation associated functional FI. Biopsychosocial factors play a crucial role in the pathogenesis. Limited physiological testing of anorectal function is recommended in the diagnostic procedures, particularly in children with atypical symptoms and possible organic disorders. Management of FI needs a multidisciplinary approach which includes establishment of an effective doctor-patient partnership, understanding the underlying mechanisms, pharmacotherapy and behavioural treatment. Approximately 15% of children with functional nonretentive faecal incontinence (FNRFI) had the same symptoms at the age of 18 years. Conclusion Significant therapeutic advances have been made for retentive faecal incontinence, but treatment options for functional nonretentive faecal incontinence are limited. Limited long-term outcome data show that the majority outgrow faecal incontinence. A substantial proportion of children progress to adulthood with faecal incontinence. © 2012 Blackwell Publishing Ltd.
Rajindrajith S.,University of Kelaniya |
Devanarayana N.M.,University of Kelaniya
Journal of Neurogastroenterology and Motility | Year: 2011
Constipation in children is a common health problem affecting 0.7% to 29.6% children across the world. Exact etiology for developing symptoms is not clear in children and the majority is considered to have functional constipation. Alteration of rectal and pelvic floor function through the brain-gut axis seems to play a crucial role in the etiology. The diagnosis is often a symptom-based clinical process. Recently developed Rome III diagnostic criteria looks promising, both in clinical and research fields. Laboratory investigations such as barium enema, colonoscopy, anorectal manometry and colonic transit studies are rarely indicated except in those who do not respond to standard management. Treatment of childhood constipation involves several facets including education and demystification, toilet training, rational use of laxatives for disimpaction and maintenance and regular follow-up. Surgical options should be considered only when medical therapy fails in long standing constipation. Since most of the management strategies of childhood constipation are not evidence-based, high-quality randomized controlled trials are required to assess the efficacy of currently available or newly emerging therapeutic options. Contrary to the common belief that children outgrow constipation as they grow up, a sizable percentage continue to have symptoms beyond puberty. © 2011 The Korean Society of Neurogastroenterology and Motility.
Ranawaka U.K.,University of Kelaniya |
de Silva H.J.,University of Kelaniya
PLoS Neglected Tropical Diseases | Year: 2013
Snakebite is classified by the WHO as a neglected tropical disease. Envenoming is a significant public health problem in tropical and subtropical regions. Neurotoxicity is a key feature of some envenomings, and there are many unanswered questions regarding this manifestation. Acute neuromuscular weakness with respiratory involvement is the most clinically important neurotoxic effect. Data is limited on the many other acute neurotoxic manifestations, and especially delayed neurotoxicity. Symptom evolution and recovery, patterns of weakness, respiratory involvement, and response to antivenom and acetyl cholinesterase inhibitors are variable, and seem to depend on the snake species, type of neurotoxicity, and geographical variations. Recent data have challenged the traditional concepts of neurotoxicity in snake envenoming, and highlight the rich diversity of snake neurotoxins. A uniform system of classification of the pattern of neuromuscular weakness and models for predicting type of toxicity and development of respiratory weakness are still lacking, and would greatly aid clinical decision making and future research. This review attempts to update the reader on the current state of knowledge regarding this important issue. © 2013 Ranawaka et al.
Halwatura D.,University of Kelaniya |
Najim M.M.M.,University of Kelaniya
Environmental Modelling and Software | Year: 2013
Hydrologic simulation employing computer models has advanced rapidly and computerized models have become essential tools for understanding human influences on river flows and designing ecologically sustainable water management approaches. The HEC-HMS is a reliable model developed by the US Army Corps of Engineers that could be used for many hydrological simulations. This model is not calibrated and validated for Sri Lankan watersheds and need reliable data inputs to check the suitability of the model for the study location and purpose. Therefore, this study employed three different approaches to calibrate and validate the HEC-HMS 3.4 model to Attanagalu Oya (River) catchment and generate long term flow data for the Oya and the tributaries.Twenty year daily rainfall data from five rain gauging stations scattered within the Attanagalu Oya catchment and monthly evaporation data for the same years for the agro meteorological station Henarathgoda together with daily flow data at Dunamale from 2005 to 2010 were used in the study. GIS layers that were needed as input data for the flow simulation were prepared using Arc GIS 9.2 and used in the HEC-HMS 3.4 calibration of the Dunamale sub catchment using daily flow data from 2005 to 2007. The model was calibrated adjusting three different methods. The model parameters were changed and the model calibration was performed separately for the three selected methods, the Soil Conservation Service Curve Number loss method, the deficit constant loss method (the Snyder unit hydrograph method and the Clark unit hydrograph method) in order to determine the most suitable simulation method to the study catchment. The calibrated model was validated with a new set of rainfall and flow data (2008-2010). The flows simulated from each methods were tested statistically employing the coefficient of performance, the relative error and the residual method. The Snyder unit hydrograph method simulates flows more reliably than the Clark unit hydrograph method. As the loss method, the SCS Curve Number method does not perform well. •HEC-HMS can reliably be used to simulate flows in ungauged tropical watersheds.•Snyder unit hydrograph method is more reliably than Clark unit hydrograph method.•As the loss method, the SCS Curve Number method does not perform well.•Deficit and constant method is more reliable than SCS Curve Number method. © 2013 Elsevier Ltd.
Premathilake R.,University of Kelaniya
Quaternary Science Reviews | Year: 2012
This study utilizes radiocarbon-dated pollen, spores, . Sphagnum spp. macrofossils and total organic carbon proxies to examine variability of past climate, environment and human activity in montane rainforest, grassland and wetland of the Horton Plains (HP), central Sri Lanka since the Last Glacial Maximum (LGM). The LGM is largely characterized by grasslands and xerophytic herbs dominated open habitats. Arid-LGM punctuated climatic ameliorations, which took place in short episodes. Humans appear to have reached the HP ecosystem after 18,000 cal yrs BP occasionally. The first Intertropical Convergence Zone (ITCZ) induced changes in South West Monsoon (SWM) rains occurred at low latitudes between 16,200 and 15,900 cal yrs BP suggesting an onset of monsoon rains. After this event, monsoon rains weakened for several millennia except the period 13,700-13,000 cal yrs BP, but human activity seems to have continued with biomass burning and clearances by slash and burn. Very large size grass pollen grains, which are morphologically similar to pollen from closer forms of . Oryza nivara, were found after 13,800 cal yrs BP. Early Holocene extreme and abrupt climate changes seem to have promoted the forms of . O. nivara populations in association with humans. New data from the HP would therefore be most interesting to investigate the dispersal and use of domesticated rice in South Asia. © 2012 Elsevier Ltd.
Agency: Cordis | Branch: H2020 | Program: RIA | Phase: HCO-05-2014 | Award Amount: 3.61M | Year: 2015
South Asians, who represent one-quarter of the worlds population, are at high risk of type-2 diabetes (T2D). Intensive lifestyle modification (healthy diet and physical activity) is effective at preventing T2D amongst South Asians with impaired glucose tolerance, but this approach is limited by high-cost, poor scalability and low impact on T2D burden. We will complete a cluster-randomised clinical trial at 120 locations across India, Pakistan, Sri Lanka and the UK. We will compare family-based intensive lifestyle modification (22 health promotion sessions from a community health worker, active group, N=60 sites) vs usual care (1 session, control group, N=60 sites) for prevention of T2D, amongst 3,600 non-diabetic South Asian men and women with central obesity (waist100cm) and/or prediabetes (HbA1c6.0%). Participants will be followed annually for 3 years. The primary endpoint will be new-onset T2D (physician diagnosis on treatment or HbA1c6.0%, predicted N~734 over 3 years). Secondary endpoints will include waist and weight in the index case and family members. Our study has 80% power to identify a reduction in T2D risk with family-based intervention vs usual care of: 30% in South Asians with central obesity; 24% in South Asians with prediabetes; and 24% overall. Health economic evaluation will determine cost-effectiveness of family based lifestyle modification for prevention of T2D amongst South Asians with central obesity and / or prediabetes. The impact of gender and socio-economic factors on clinical utility and cost-effectiveness will be investigated. Our results will determine whether screening by waist circumference and/or HbA1c, coupled with intervention by family-based lifestyle modification, is an efficient, effective and equitable strategy for prevention of T2D in South Asians. Our findings will thereby provide a robust evidence base for scalable community-wide approaches to reverse the epidemic of T2D amongst the >1.5 billion South Asians worldwide.
Agency: Cordis | Branch: FP7 | Program: CP-FP-SICA | Phase: HEALTH.2011.2.4.3-4 | Award Amount: 3.90M | Year: 2011
This project focuses on identification of epigenetic risk factors underlying the increased rates of type-2 diabetes (T2D) amongst South Asians in their home countries, migrants to Europe and other parts of the world. Known environmental and genetic factors explain only a small part of the increased risk of T2D among South Asians, who constitute the highest numbers of people with T2D worldwide. We hypothesise that epigenetic modification contributes to the increased T2D risk amongst South Asians. We will carry out an epigenome-wide scan of DNA methylation in whole blood, among T2D cases and controls from non-migrant (living in India or Pakistan) and migrant (living in the UK) South Asians. Further testing of top-ranking markers will be carried out in South Asian T2D cases and controls from UK, India, Mauritius, Pakistan, Singapore and Sri Lanka. We will use results to investigate the mechanisms underlying the epigenetic modifications identified, to develop a predictive panel of lifestyle, environmental, genetic and epigenetic markers increasing susceptibility to incident T2D in South Asians, and to quantify the contribution of these risk factors to T2D amongst South Asians in diverse regional settings. This research will improve understanding of epigenetic mechanisms underlying T2D, and may enable development of novel biomarkers and therapeutic strategies to reduce the burden of T2D amongst South Asians worldwide.