Showing papers by "University of Peradeniya published in 2022"

Climate Adaptation by Farmers in Three Communities in the Maldives

Abstract: The Maldives, a small island nation, is continuously facing climate change impacts and adapting to them. One of the risks of climate change in the Maldives is the sea-level rise that threatens the livelihoods of Maldivians. This paper looks at how farmers in the Maldives adapt to changes in climatic conditions by interviewing farmers on three islands: Fuamulaku, Gan, and Fonadhoo. The study employed 24 in-depth interviews with farmers in these islands. Narratives from a few selected farmers are used to highlight the role of social capital and social networks in shaping farmers’ approaches to climate change adaptation. The study shows that family interactions, social networks, and available information build the foundation of their social capital. It identifies the need for effective dissemination of scientific information to farmers and demonstrates that strengthening social capital paves the way for improving their adaptive capacity.

The Effect of Fouling Materials on Permeability Behaviour of Large Size Granular Materials

Abstract: Granular materials are discontinuous, highly heterogeneous materials that are randomly assembled. They are widely used in civil engineering constructions such as in highway pavements, rockfill dams, drainage systems, and rail tracks. In this study, the granular type ballast aggregates were used to analyze its permeability behaviour when it is contaminated with fine particles. The ballast provides rapid drainage and supports the heavy loads apply from the trains. However, the accumulation of fines in the ballast layer which is known as fouling causes disturbance in track drainage which is leading for reduced track performance and frequent track maintenance. Therefore, this study focuses on the determination of permeability behavior of fouled ballast with different levels of fouling experienced in Sri Lankan rail tracks and to propose the stage at which track maintenance should be done. A series of constant head permeability tests were conducted by using large-scale permeability apparatus built in the laboratory. Sandy clay was used as the fouling material and the gradation of ballast currently adopted in Sri Lanka was used. Void contamination index (VCI) was selected to indicate the fouling level and the permeability of ballast was measured at different VCI values. A numerical analysis was carried out to simulate two-dimensional flow under actual track geometry in quantifying the drainage capacity of ballast in different degrees of fouling. By using constant head permeability test results as inputs, drainage capacities at different cases were obtained from the numerical analysis and classified according to the drainage capacity criteria. Based on the research outcomes, a relationship between the hydraulic conductivity of ballast and the VCI% was obtained. Also, the critical fouling levels in different layers of ballast were identified to commence the ballast cleaning work at the rail track site.

Synopsis of Biomarkers of Atheromatous Plaque Formation, Rupture and Thrombosis in the Diagnosis of Acute Coronary Syndromes

Abstract: Acute coronary syndrome is the main cause of mortality and morbidity worldwide and early diagnosis is a challenge for clinicians. Though cardiac Troponin, the most commonly used biomarker, is the gold standard for myocardial necrosis, it is blind for ischemia without necrosis. Therefore, ideal biomarkers are essential in the care of patients presenting with symptoms suggestive of cardiac ischemia. The ideal biomarker or group of biomarkers of atheromatous plaque formation, rupture and thrombosis for timely and accurate diagnosis of acute coronary syndrome is a current need. Therefore, we discuss the existing understanding and future of biomarkers of atheromatous plaque formation, rupture and thrombosis of acute coronary syndrome in this review. Keywords were searched from Medline, ISI, IBSS and Google Scholar databases. Further, the authors conducted a manual search of other relevant journals and reference lists of primary articles. The development of high-sensitivity troponin assays facilitates earlier exclusion of acute coronary syndrome, contributing to a reduced length of stay at the emergency department, and earlier treatment resulting in better outcomes. Although researchers have investigated biomarkers of atheromatous plaque formation, rupture and thrombosis to help early diagnosis of cardiac ischemia, most of them necessitate validation from further analysis. Among these biomarkers, pregnancy-associated plasma protein-A, intercellular adhesion molecule-1, and endothelial cell-specific molecule- 1(endocan) have shown promising results in the early diagnosis of acute coronary syndrome but need further evaluation. However, the use of a combination of biomarkers representing varying pathophysiological mechanisms of cardiac ischemia will support risk assessment, diagnosis and prognosis in these patients and this is the way forward.

Investigation on the Performance of Multi-stacked Floating Wetlands for Leachate Treatment in a Controlled Environment

Abstract: Leachate releasing from solid waste dump sites or sanitary landfills, is rich in organic pollutants and heavy metals, contributes heavily in contamination of water bodies. Therefore, it is necessary to treat the landfill leachate appropriately up to the effluent standards, before releasing them in to the environment. Constructed wetlands have been identified as an appropriate technology for wastewater treatment in tropical developing countries. However, despite many advantages the large land area requirement and the impacts of outdoor environmental conditions have been identified as major limitations for application of this technology at many places. Therefore, this study has been focused on reducing the land area requirement by designing a multi-stacked floating wetland system. The experimental set-up had three multi-stacked wetland systems, each containing 3 units of 32 cm × 52 cm × 28 cm (length:width:height) in size stacked one over the other and planted with Eichhornia crassipes (common water hyacinth). Two of them were placed inside a greenhouse, while the remaining system was kept outside the greenhouse in open environment. One of the system kept inside the greenhouse was set with a supplementary lighting arrangement. All three units were fed with synthetic leachate to achieve a 60 cm/day hydraulic loading rate (HLR). Results showed that the wetland system kept inside the greenhouse with supplementary lighting had a significant positive impact in removing BOD5, COD, TOC, Pb, Cu and Zn with average removal efficiencies of 77.4%, 79.1%, 97.9%, 89%, 89.3% and 87.7%, respectively.

Safety and efficacy of therapeutic taping in primary dysmenorrhea: a systematic review and meta-analysis

Abstract: Primary dysmenorrhea (PD) is a common gynecological condition among adolescent and adult women. Several pharmacological and alternative therapies (e.g. therapeutic taping) have been used to treat PD, with varying effect. This systematic review and meta-analysis was performed to evaluate the safety and efficacy of therapeutic taping on clinical symptoms of PD, considering pain as the primary outcome. MEDLINE, Cochrane Library, Embase, PEDro, CINAHL and gray literature sources were searched from inception to February 2022 for randomized controlled trials (RCTs) that assessed the effect of therapeutic taping for PD. The language was restricted to English. A total of ten studies were included in the systematic review, involving 685 participants. Eight studies were included in quantitative analysis. The quality of the studies ranged from 4 to 7 with a median of 5 as assessed by PEDro scale. Meta-analyses indicated short-term improvements of pain compared to sham and no interventions. Elastic therapeutic taping (ETT) indicated short term improvements in anxiety associated with PD. Moderate to high quality of evidence suggested that ETT is an effective intervention in improving pain, anxiety, and quality of life of women with PD. A scarcity of evidence on the long-term effects of therapeutic taping in PD is observed.

Holistic Interpretation of Public Scenes Using Computer Vision and Temporal Graphs to Identify Social Distancing Violations

Abstract: Social distancing measures are proposed as the primary strategy to curb the spread of the COVID-19 pandemic. Therefore, identifying situations where these protocols are violated has implications for curtailing the spread of the disease and promoting a sustainable lifestyle. This paper proposes a novel computer vision-based system to analyze CCTV footage to provide a threat level assessment of COVID-19 spread. The system strives to holistically interpret the information in CCTV footage spanning multiple frames to recognize instances of various violations of social distancing protocols, across time and space, as well as identification of group behaviors. This functionality is achieved primarily by utilizing a temporal graph-based structure to represent the information of the CCTV footage and a strategy to holistically interpret the graph and quantify the threat level of the given scene. The individual components are evaluated in a range of scenarios, and the complete system is tested against human expert opinion. The results reflect the dependence of the threat level on people, their physical proximity, interactions, protective clothing, and group dynamics, with a system performance of 76% accuracy.

Diversity and Geographic Distribution of Dog Tick Species in Sri Lanka and the Life Cycle of Brown Dog Tick, Rhipicephalus sanguineus Under Laboratory Conditions

Abstract: This study determined the diversity and distribution of tick species infesting domestic dogs and the life cycle parameters of the dominant dog tick species. An island-wide, cross-sectional survey of tick species infesting domestic dogs was carried out, and the life cycle of the most commonly occurring dog tick, Rhipicephalus sanguineus was studied under laboratory conditions. A total of 3026 ticks were collected from 1219 dogs in all 25 districts. Eight species in five genera were identified: R. sanguineus (63.4%), R. haemaphysaloides (22.0%), Haemaphysalis bispinosa (12.5%), Haemaphysalis intermedia (0.9%), Haemaphysalis turturis (0.6%), Amblyomma integrum (0.4%), Dermacentor auratus (0.2%) and Hyalomma sp (0.1%). R. sanguineus was the dominant species in the Dry and Wet zones, while R. haemaphysaloides was the dominant species in the Intermediate Zone. Species diversity (Shannon diversity index H) was 1.135, 1.021and 0.849 in the Intermediate, Dry and Wet zones, respectively. The three-host life cycle of R. sanguineus was completed within 70–126 days, and all three stages successfully fed on New Zealand white rabbits under laboratory conditions. The Reproductive Efficiency Index (REI) and Reproductive Fitness Index (RFI) were 50.8 ± 9.69 and 9.1 ± 5.01, respectively. Larger females had higher reproductive success. Of the eight species infesting domestic dogs in Sri Lanka, R. sanguineaus was the most frequently occurring tick species. The three-host life cycle of R. sanguineus was successfully completed within an average of 98 days on New Zealand white rabbits. The number of eggs laid, duration of the pre-oviposition period, incubation period and parasitic periods of all three life stages were lower than in previous records.

Nanomaterials for Energy Storage Applications

Abstract: Electrical energy generation plays an important role in directly influencing the economic and social activities in a country. However, the amount of electricity that can be generated is relatively fixed over short periods of time, although demand for electricity fluctuates throughout the day. Therefore, developing technology to store electrical energy is extremely important to meet the demand in electricity specially when the sources of electricity generation include renewable ones such as solar and wind where power capacity varies with time. Also, energy storage is a vital requirement for portable/mobile electrical and electronic systems. In general, energy storage systems can be classified into batteries, fuel cells, and capacitors. Although fuel cells have very high energy densities, they are poor in terms of power density. However, batteries such as Li-ion show a good compromise between energy and power densities which have made it the preferred choice for portable electronics. In contrast, capacitors have very high power densities which can provide energy bursts of high current (at fixed voltage). The aim of the chapter is to focus on research studies which involve nanomaterials to improve the performance of aforementioned energy storage techniques, related challenges, and future prospect.

Assessment of Shear Strength Parameters of Marine Dredge Sand

Abstract: Cohesion and friction angle represents the shear strength parameters of soils. Linear Mohr–Coulomb envelope is the widely used theoretical concept to describe the shear strength of the soils which are related to the geotechnical analysis and designs. However, sand deviates considerably from linear Mohr–Coulomb envelope due to the effects of factors such as confining pressure, relative density, mineralogy, particle crushing, particle size distribution and fines content. The Colombo port city development project, which is in coastal region, reclaimed dredge sand over 13 m depth. This project was proposed to include low rise and high rise buildings all over the reclaimed land where the type of foundation may vary depending upon the structural loads and subsurface conditions. Therefore, determination of shear strength parameters for different loading condition is of utmost importance to determine the bearing capacity and to select the dimensions of foundations. In this study, basic engineering properties of reclaimed sand collected from Colombo port city project were examined. A series of laboratory direct shear tests were conducted to determine the variation of shear stress over different normal stresses. From the analysis of experimental data, it was revealed that shear stress of dredged sand varies linearly with normal stress up to 100 kPa and showed nonlinear behavior thereafter.

Collapsibility Characteristics of a Residual Soil in Matale District, Sri Lanka

Abstract: Collapse is termed as the large volume reduction taken place in partially saturated soils upon wetting under a particular applied pressure, that are otherwise resistant to much larger applied stresses under normal conditions. This phenomenon can be commonly witnessed in Aeolian, alluvial and colluvial type of soils across the globe though not much reported to occur in residual soils. However, a residual soil too can develop into a collapsible soil under certain conditions. In this study, undisturbed soil samples obtained from a construction site in Matale District, Sri Lanka consisting of a residual soil which exhibited unusually low values of dry density was subjected to a series of double oedometer tests to determine the collapse potential and to investigate the variation of collapse potential with the applied normal pressure, relative compaction and degree of saturation. The study revealed that the collapse potential of different locations of the site is directly proportional to the applied normal pressure and inversely proportional to both relative compaction and degree of saturation. Also, it was identified that samples remolded maintaining their in situ dry density can increase the collapse potential of a slightly collapsible soil. A multi-variate regression analysis was performed to develop a relationship for collapse potential in terms of applied normal pressure, relative compaction and degree of saturation.

Harnessing the untapped potential of indigenous cow milk in producing set-type yoghurts: case of Thamankaduwa White and Lankan cattle

Abstract: Abstract This research paper assessed textural, microstructural, sensory and colour properties of set-yoghurts produced using milk from two indigenous cattle types, Thamankaduwa White (TW) and Lankan cattle (LC) compared to two generic cattle breeds, Friesian and Jersey. Instrumental texture profile (firmness, adhesiveness, cohesiveness and springiness), colour space ( L * a * b *) and scanning electron micrographs of set-yoghurts during 21 d of storage (4 ± 1°C) were evaluated. Sensory quality attributes were evaluated with 40 untrained panellists using a five-point hedonic scale. Set-yoghurts prepared using indigenous cow milk showed higher ( P < 0.05) firmness, cohesiveness and apparent viscosity values compared to those prepared using generic cow milk. As revealed by micrographs, set-yoghurts made from TW milk had lesser and smaller void spaces and a dense protein gel network than gels made from LC and the two generic breeds. The gel network made from Friesian milk showed a comparatively larger porous gel structure and thinner protein strands resulting in a weaker gel than other milk gels. The highest lightness ( L *) and yellowness ( b *) were observed from set-yoghurt produced from Friesian and LC milk, respectively. Set-yoghurts from TW milk had the highest ( P < 0.05) sensory scores for all sensory attributes. The lowest sensory acceptance was recorded in set-yoghurt made from Friesian milk. Thus, milk from TW and LC is likely to be suitable in producing set-yoghurts with superior textural, microstructural and sensory properties, compared to milk from Jersey and Friesian. Our results suggest the merits of using indigenous cow milk in producing set-yoghurts and, thereby, prioritizing the preservation of the genetic pool of these indigenous breeds.

Protective immunity in a sample of healthy adults following vaccination with a more cost effective recombinant HBsAg vaccine

Abstract: Vaccines against hepatitis B virus (HBV) infection became available from 1982, however, the HBV infection remains as a public health issue due to infection among susceptible individuals. Many HBV vaccines are available and until 2012, Sri Lanka has been using vaccines produced by different Pharmaceutical companies. Since 2012, Sri Lanka imported HBV vaccine from Serum Institute of India as the product was more cost effective. However, the immune response to this vaccine has never been studied in the country. The current study was carried out to assess the immune response (anti-HBs) to the recombinant HBV surface antigen (HBsAg) vaccine (Serum Institute, India), which is currently used in the state healthcare sector of Sri Lanka. A sample of vaccinated healthy adults (n=529), age ranged between 20-29 years were enrolled in this study after completing the standard 3-dose regimen of HBV vaccination from early 2015 to 2016. Sociodemographic data were collected using a self-administrated questionnaire. Serum samples were tested to detect the presence of anti-HBs using an enzyme linked immunosorbent assay (ELISA) and the results were analyzed using MS-Excel 2010. Based on the results, 96.8% of the healthy adults had protective immune response with anti-HBs levels > 10 mIU/mL. Gender did not show an association with levels of anti-HBs. All the ethnic groups in the study sample exhibited >90% of protective immune response. The more cost effective recombinant HBsAg vaccine taken by the healthy adults in the present study was effective in inducing the protective immunity.

Epidemiology and renal injury following 2-methyl-4-chlorophenoxyacetic acid (MCPA) poisoning

Abstract: 2-Methyl-4-chlorophenoxyacetic acid (MCPA) is a widely used chlorophenoxy herbicide. MCPA poisoning causes mitochondrial dysfunction, which can lead to kidney injury and death. The objective of this study is to describe the epidemiology, case fatality and extent of renal injury in a large cohort of MCPA self-poisonings. The study consists of two parts: (1) A report of epidemiological data and clinical outcomes in MCPA poisoned patients in Sri Lanka between 2002 and 2019; (2) Evaluation of acute kidney injury (AKI) using renal biomarkers in a subset from this cohort. Serum creatinine (sCr) and biomarkers were measured soon after hospitalization (2 [IQR 1-3] h) and at different time intervals. We measured serum biomarkers: sCr, cystatin C (sCysC), creatine kinase (CK), and urinary biomarkers: creatinine, kidney injury molecule-1 (KIM-1), clusterin, albumin, beta-2-microglobulin (β2M), cystatin C, neutrophil gelatinase-associated lipocalin (NGAL), osteopontin (OPN), trefoil factor 3 (TFF3) and cytochrome C (CytoC). Kidney Disease Improving Global Outcomes (KDIGO) criteria was used to define acute kidney injury (AKI). There were 1653 patients; 65% were male. The median time from ingestion to examination was 3:54 (IQR 2:19-6:57) h. The overall case-fatality rate was 5.3%. Patients who died were older (42 [IQR 33.5-54] vs 27 [IQR 20-37] for survivors). The median estimated amount of MCPA ingested by patients who died was also greater (88 [IQR 34-200] vs. 30 [IQR 15-63] ml in survivors). Moderate to severe AKI (AKI2/3) was uncommon (6/59 patients in the biomarker study had KDIGO stage 2 or 3). Most patients in AKI2/3 group with increased sCr were older (median age 35 years [IQR 27-41]) compared to No AKI (23 years (19-29) years) or AKI1 (26 years (21-40) years) group who had no or mild increase in sCr. These patients had no pre-existing kidney diseases. In these patients, serum creatinine (maximum medium concentration; 1.12 [IQR 0.93-1.67] mg/dl) and CK (maximum medium concentration; 284 [IQR 94-428] U/l) were increased but sCysC (maximum medium concentration; 0.79 [IQR 0.68-0.81] mg/l) remained in the normal range within 72 h. All urinary biomarkers performed poorly in diagnosing AKI (area under the receiver operating characteristic curve < 0.68). The higher numbers of men with MCPA poisoning likely reflects greater occupational access to pesticides. Fatal outcome and higher ingested dose were more common in the elderly. Significant AKI with tubular injury biomarkers was uncommon. Most people with raised sCr were older and appeared to have no pre-existing kidney disease.