Browsing by Author "Wijesinghe, S."

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Arterial tortuosity syndrome: A rare inherited form of connective tissue disorder with SLR2A10 gene mutation
(Sri Lanka College of Paediatricians, 2022) Wijesinghe, S.; de Silva, D.; Samarasinghe, D.; Irugalbandara, S.
No abstract available
Comparative Effect of Parasitism of Ciliated Protists Associated with Selected Vector Mosquito Larvae in Selected Rice Field Habitats in Ganewatte, Kurunegala District, Sri Lanka
(Institute of Biology Sri Lanka, 2021-09) Wijesinghe, S.; Amarasinghe, L.D.
Mosquito breeding sites provide habitats for diversifying naturally occurring microbiota and favour different types of interactions including parasitism. This study was carried out to determine the natural occurrence of ciliated protist parasites associated with selected vector mosquito species inhabiting rice fields in Ganewattha area in Kurunegala district in Sri Lanka and to compare their parasitic effects on the selected vector mosquito larvae. Mosquito samples were collected from five rice field sites during the period from June to December 2020. The samples were observed for epibionts/parasitic infections under the microscope. Moribund or dead mosquito larvae in each sample collection were observed for internal parasitic infections. A comparative study was carried out to determine the lethal effect of ciliated organisms on Culex tritaeniorhynchus (n=50) and Culex gelidus larvae (n=50) in replicated trials (R=3). The minimum number of V. microstoma that cause a lethal effect on Cx. tritaeniorhynchus third instar larvae (n=100) was determined by a bioassay with ten replicates and two controls per each replicate. A total of 1650 third instar mosquito larvae of Culex tritaeniorhynchus (62.8%) and Culex gelidus (37.2%) were collected in this study. Ciliated protists namely Vorticella microstoma, Zoothamnium spp. and Chilodonella spp. associated with both species of mosquito larvae were identified. Results revealed that V. microstoma has the potential of infection to cause 71.33 (±5.23) mean percentage mortality of Cx. tritaeniorhynchus larvae. A minimum of 1000 V. microstoma is required to kill a third instar larva of Cx. tritaeniorhynchus at 69.60 (±2.40) hours of exposure. Culex gelidus larvae showed only 41.33 (±3.43) mean percentage mortality. This study concludes that V. microstoma is the most successful ciliated parasite as a killing agent of Culex tritaeniorhynchus vector mosquito larvae. Their abundance and effectiveness may contribute to develop them as an effective biocontrolling agent in the future.
Comparative study on the larvicidal effect of some ciliated protists on Culex gelidus, Culex tritaeniorhynchus, and Aedes aegypti in Sri Lanka
(Parasitology Research, 2022) Wijesinghe, S.; Amarasinghe, D.
Rice fields in Sri Lanka create suitable breeding places for vector mosquitoes. Such sites provide habitats for diversified naturally occurring microbiota. Ciliated protists, Zoothamnium sp., Chilodonella sp., and Vorticella microstoma are among such microbiota found in vector mosquito habitats especially in rice field habitats in Sri Lanka. The present study was car- ried out to determine the comparative larvicidal effect of these ciliated protists collected from naturally infested mosquito larvae in some rice-field habitats in Kurunegala, Sri Lanka, against vector mosquito larvae. Vector mosquito larvae, Culex tritaeniorhynchus, and Culex gelidus were reared in the laboratory from field-collected water samples while Aedes aegypti mosquito larvae were reared using egg sheets, for the laboratory bioassays. V. microstoma showed the potential for infec- tion and mortality of Cx. tritaeniorhynchus larvae (71.33% ± 5.23). Results revealed a minimum of 1000 V. microstoma is required to kill a single third instar larva of Cx. tritaeniorhynchus at 69.60 ± 2.40 h of exposure. Cx. gelidus larvae showed 41.33% ± 3.43 mortality due to V. microstoma infestation. However, none of the ciliates were effective against Ae. aegypti larvae. Chilodonella sp. was very occasionally reported during this study hence was not possible to the mass rear for experi- mentations. This study concludes that V. microstoma is an effective ciliated parasite of Cx. tritaeniorhynchus larvae. Due to their effectiveness and eco-friendly nature, this species can be developed as an effective bio-controlling agent against Cx. tritaeniorhynchus mosquito species.
An Initial Study on Understanding the Effect of Question Surface Features on Students' Responses
(In: Proceedings of the International Postgraduate Research Conference 2017 (IPRC – 2017), Faculty of Graduate Studies, University of Kelaniya, Sri Lanka., 2017) Rupasinghe, T.P.; Samarasekere, P.W.; Wijesinghe, S.
Assessment is one of the key feedback mechanisms in measuring the effectiveness of the teaching and learning process of science education. One of the challenges in evaluating through the assessments is that students often focus on surface features of the questions such as the length, vocabulary, or the phrasing, rather than on underlying scientific principles of the question. According to educational theories, the wording of the questions has a substantial impact on the students’ performance during the science examinations. However, in the current science education context, there is only a limited number of research studies available which provides an insight into the relationship between students’ performance and the question features. The objective of the current study is to investigate the effect of the surface features of the questions on students’ performance. Herein, we have investigated how wording of an examination question could affect students’ performance. The study was conducted as a part of the Chemistry for Technology course (sample size =86) at the Faculty of Computing and Technology, University of Kelaniya, Sri Lanka. At the final examination, two different types of constructed-response questions were given to students. One was a Direct question which included solving a question using a basic chemistry concept and simple arithmetic calculations. Second version (Wordy question); included the same data as in the Direct version but with a related scenario. In the Wordy question, students had to go through several sentences to pick relevant data to solve the problem. It is expected that, the scenario given in the Wordy version could lead to a deeper understanding of the question and thereby result in better students’ performance. Marks obtained for the two versions were averaged and compared to investigate whether there is any significance of the wording towards the performance of students. Average mark for the Wordy question yielded to be 43% while that of the Direct question was 63%. Moreover, the attempt rate (no of student who had attempted) was significantly low as 39% for the Wordy version of the question. According to the performance of the students it was clear that the students meet a considerable difficulty in the understanding the Wordy questions. It can be concluded that the use of items such as syntactically complex sentences in examinations could decrease the performance of the students. Moreover, significantly lower attempt rate observed in the case of the Wordy questions suggests that the students tend to skip lengthy questions even without trying to identify the basic scientific principle lying behind. Hence it can be concluded that the surface features such as the length, type of words can play a key role in students’ performance at the examinations. Currently, further studies are being conducted to gain more insight into this.
An Initial Study on Understanding the Effect of Questions Structure on Students' Exam Performance
(3rd International Conference on Advances in Computing and Technology (ICACT ‒ 2018), Faculty of Computing and Technology, University of Kelaniya, Sri Lanka., 2018) Wijesinghe, S.; Irosha, K.P.C.; Rupasinghe, T.
The main challenge in evaluating students’ performance is creating effective assessments which appraises students’ learning rather than their memory power and the practice. According to education theories, creative and carefully designed assessments can clearly evaluate the degree of learning in students. “Scaffolding” which refers to the degree to which a question guides the student through the problem-solving process is a widely used method in aiding students’ learning and conceptual understanding and assessing students’ performance in Science and Technology education. The objective of the current study was to understand the impact of exam question structure on the performance of first year undergraduates specifically focusing on understanding the effect of scaffolded questions. In the current Sri Lankan science education context, there is only a limited number of research studies that are available which provides an insight into the relationship between students’ performance and question features. Current study which was designed to address this issue was conducted as a part of the Chemistry for Technology course at the Faculty of Computing and Technology, University of Kelaniya, Sri Lanka. In this study, two different structures of the same questions were given to students as a part of an in class quiz. First one was a direct question and the second version (scaffolded question) included the same question in a step by step manner and in the latter version, students had to answer several steps to solve the problem. Marks obtained for the two versions were averaged and compared to investigate whether there is any significance of the structure of the questions towards the performance of students. Average mark for the scaffolded question was 82(±20) and the direct question was 71(±35). According to the results, it was clear that the students meet a considerable difficulty in the understanding the direct questions and the scaffolding of questions results in an increase of the performance of students. According to preliminary data, it can be concluded that scaffolding of questions preferentially assist students performance at examinations and surface features such as the structure of the question can play a key role in students’ performance at the examinations. Further studies are currently being conducted to understand whether there is any specific correlation between the improvement in performance as a consequence of scaffolding with the gender, school district and students’ English literacy.
Inquiry Based Learning Approach in Introductory Level Science Education.
(In: Proceedings of the International Postgraduate Research Conference 2017 (IPRC – 2017), Faculty of Graduate Studies, University of Kelaniya, Sri Lanka., 2017) Rupasinghe, T.P.; Samarasekere, P.W.; Wijesinghe, S.
In today‘s world, science education has been shifted from the traditional ―Passive Learning‖ to the ―Active Learning‖ approach. Although traditional teaching is effective in disseminating large body of content to a large number of students, it often fails to stimulate students‘ enthusiasm, confidence, and motivation, and thereby fails to enhance critical thinking and problem solving skills. The result is a mismatch in job market demand and supply as the graduates are lacking in appropriate skills and competencies needed in the job market, leading to increased unemployment among the graduates. In order to promote meaningful science education through concepts of Active Learning, number of different teaching pedagogies have been introduced, such as Problem Based Learning (PBL), Activity Based Learning (ABL) and Inquiry Based Learning (IBL). Current study focuses on the implementation of an Inquiry Based instructional design to enhance chemistry laboratory skills of undergraduates. Typically, chemistry laboratory classes utilize a ―cook book‖ approach where students follow the directions in an experimental procedure. Although this approach is effective in teaching a new laboratory technique, it highly limits the level of learning as it doesn‘t provide a comprehensive understanding of the real world applications of the experiment. In the current IBL approach, each laboratory class was composed of four components, (i) Case Study session (ii) Pre-lab Assignment (iii) Laboratory session and (iv) a Post-lab activity. Case study session was an interactive group activity where a comprehensive real world problem/scenario related to each laboratory topic was discussed prior to the laboratory session. Students were asked to think critically on the scenario, and design an experiment to solve the problem. An inclusive learning environment was created in the classroom where each group had to present their solution and provide feedback to peers. Pre-lab assignment was designed to facilitate and assess students‘ subject knowledge and logical thinking, while the post-lab activity was designed to provide a deeper understanding by emphasizing the theoretical background. Assessment of this novel IBL approach consisted of student surveys, feedbacks, and comparison of students‘ grades. Significantly higher student satisfaction and performance was observed in the study signifying the positive impact of active learning towards the success of students‘ learning.
Investigation of the Impact of Clay as a Bulking Agent for Food Waste Composting at a Controlled Raised-up Temperature
(3rd International Conference on Advances in Computing and Technology (ICACT ‒ 2018), Faculty of Computing and Technology, University of Kelaniya, Sri Lanka., 2018) Jayawardana, M.D.S.B.; Milani, Y.; Silva, C.D.; Wijesinghe, S.
In agriculture, the nourishing and substantial quality of soil can be upgraded through transfiguring organic matter in food waste into humus like substance, which is called food waste composting. This is very important as food waste leads to cause odor and pollute the environment. The moisture content (MC), nitrogen content, C/N ratio and aeration in the compost material can be altered through various bulking agents used during the process. The usage of these bulking agents enhances the biodegradation of food waste and transformation of it into effective compost. Therefore, the entire composting process relies on the indispensable role of the bulking agents. Thus, this study was ultimately aimed to evaluate the influence of using clay as the bulking agent for food waste composting at a controlled high temperature (500C). Here a controlled raised-up temperature was used to lead rapid activation of thermophilic microbes. A consecutive five-day study was carried out to analyze the fluctuations of PH, MC and organic matter content (OMC) by preparing composting feedstock using clay as the bulking agent in four different weight percentages (0%, 5%, 10% and 25%). Using a Scanning Electron Microscope (SEM) surface morphology of the samples was analyzed at the initial stage and after five days composting. The analysis of physical parameters was evident that the organic matter was effectively converted to compost at 500C as all the parameters followed the corresponding gradual fluctuations which are presented at the quality compost production. According to the results, no effect was found from clay to control the PH of the composting process of food waste samples. With the increasing of clay percentage there was no significant change of PH was noticed compared to the blank waste sample. With the increment of the clay percentage of the composting feedstock, initial MC was dropped. Furthermore, by the increasing of the clay content of the samples MC was highly reduced. Similarly, OMC was also drastically decreased with the upswing of clay percentage. According to the observations, it can be concluded that clay has been acted as a good bulking agent to food waste composting. At this elevated temperature Food waste composting process had shown a significantly improvement. Presently, further studies are being carried out to further optimize the percentage of clay for food waste composting process at elevated temperature.
Job satisfaction and mental health of Sri Lankan doctors
(SAARC Psychiatric Federation, 2013) Rodrigo, M.D.A.; Dissanayake, A.U.G.I.P.; Galhenage, J.; Wijesinghe, S.; Kuruppuarachchi, K.A.L.A.
AIM: To measure job satisfaction and mental wellbeing among medical practitioners working in Gampaha District, Sri Lanka. METHODOLOGY: A cross sectional survey was conducted on randomly selected doctors working in three large hospitals in Gampaha District, Sri Lanka in 2008 and 2009. Warr, Cook, and Wall job satisfaction scale and the 12-item General Health Questionnaire were used respectively to measure job satisfaction and mental health wellbeing of doctors. RESULTS: A total of 172 doctors responded (response rate 28.6%). Average job satisfaction score was 47.8 (range- 10-70) and 43.6% of doctors reported high job satisfaction. Better remuneration (97.1%) and better working hours (44.8%) were identified as ways to improve job satisfaction. Average GHQ-12 score was 1.9 and less than 10% scored greater than 3. No doctor reported drinking daily or using recreational drugs. CONCLUSION: The response rate was low, thus preventing generalization of findings. The majority of doctors responding had good job satisfaction.
Lipid parameters in young adults in Sri Lanka to identify high-risk persons for coronary heart disease
(University of Kelaniya, 2000) Chandrasena, L.G.; de Silva, K.I.; Wijesinghe, S.; de Silva, L.D.R.
A Preliminary Investigation of Surface Bound Iron in Mica to Develop a Methodology Combined with Magnetism to Remove Contaminated Mica from Industrial Minerals
(3rd International Conference on Advances in Computing and Technology (ICACT ‒ 2018), Faculty of Computing and Technology, University of Kelaniya, Sri Lanka., 2018) Dassanayake, K.L.M.; Subasingha, S.A.S.; Wijesinghe, S.
Sri Lanka is a country rich with industrial minerals. Mica is one of readily available industrial mineral which belongs to a group of sheet silicate (phyllosilicate) contained Aluminum (Al), Iron (Fe), Magnesium (Mg), Potassium (K), Sodium (Na) etc. as abundant elements. Mica could be easily identified by its unique flaky structure. The most common types of mica in Sri Lanka are phlogopite (blackish brown) and biotite (brownish ash). Kuruwita, Balangoda, Haputhale and Mathale areas are well-known for Mica deposits in Sri Lanka to date. If we consider the industrial use of mica, it has been frequently used in paint industry to produce exterior paints due to its ability to create a protective coating against the extreme weather conditions like rain and ultraviolet light. Mica is a good electrical insulator and a good thermal conductor also mica powder is used as a glitter to decorate pots. Although Mica is useful when it’s present as the pure mineral, a huge lose is caused in mineral industry when it is contaminated with other industrial minerals such as Calcite, Dolomite, and Kaolin. The presence of mica in trace amounts in other minerals reduces the quality of the products like in paint, ceramic and glass industries which use the above stated industrial minerals as raw materials. Therefore, the objective of the current study is to develop a methodology to remove contaminated mica form other industrial minerals although it’s present in trace levels. Herein, we have investigated about the content of surface bound Iron in mica that can be used to develop a technique combined with magnetism. As the initial stage of the procedure, surface bound iron percentages of phlogopite and biotite were determined by using UV-visible spectroscopy at 510 nm wavelength. Analysis was carried out according to the Beer-Lambert law by using a previously calculated factor from Fe2+ standards. Average surface bound iron percentage for phlogopite yield to be 0.36 (± 0.02) % while that the percentage for biotite was 0.62 (±0.01) %. According to the results observed, it seemed that these percentages of iron on outer structure of mica may be attracted to a strong magnetic field. Thus it can be concluded that surface bound iron content can be used to separate contaminated industrial minerals. Currently, further studies are being conducted using high performance techniques such as XRF to gain more insight into this.
සම්භාව්‍ය සංස්කෘති හා ක්‍රිස්තියානි සංස්කෘති අධ්‍යයනය අංශය
(Faculty of Humanities, University of Kelaniya, Sri Lanka, 2008) Wijesinghe, S.; Gamlath, I.