RESCON 2024

Permanent URI for this collectionhttps://ir.lib.pdn.ac.lk/handle/20.500.14444/2080

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Novel approach to automated solar powered hybrid dna electrophoresis equipment
(Postgraduate Institute of Science (PGIS) University of Peradeniya, Sri Lanka, 2024-11-01) Wijethunge, S. R.; Rodrigo, Chamanthi; Sandaruwan, M. G. C.; Samaraweera, Chathura
Due to a lack of domestic repair and manufacturing, Sri Lanka faces a shortage of several instruments important for research activities. Agarose gel electrophoresis equipment is a simple but vital tool in biomedical sciences specially in the areas of genetics and molecular biology. It is used to separate mixtures of DNA, RNA, or proteins according to their size and charge. There are various versions and agarose gel electrophoresis uses an electric field to separate a mixed population of macromolecules in an agarose matrix. Conventional gel electrophoresis setups further require additional separate devices such as power supplies and UV illuminators to visualize DNA. This increases the cost and requires manual monitoring during an analysis. This study addressed these issues by presenting a novel, low-cost gel electrophoresis machine that could test DNA samples, specifically to be used in Sri Lankan laboratories. The machine utilizes readily available materials in the country and integrates the gel running unit, power unit, and illuminator into a single system. User-friendly features include a high-end display with a graphical user interface (GUI), an in-built illuminator with image processing functionalities, cloud-based data management, and Raspberry Pi programmed with the help of AI to control for stand-alone operation. Additionally, the machine incorporates solar power as a secondary source and a battery management system for enhanced reliability. The cost of production is extremely lower than the current market price in the country. Therefore, this low-cost, locally sourced machine offers a sustainable solution for Sri Lankan laboratories, reducing reliance on imported equipment and minimizing maintenance costs.
Prediction of potential sulfonamide-like antimicrobial phytochemicals using KNIME and machine learning-based approach
(Postgraduate Institute of Science (PGIS) University of Peradeniya, Sri Lanka, 2024-11-01) Swetha, B.; Wijesinghe, W. R. P.
Sulfonamide drugs are the first synthesised, selectively toxic antibiotics. They mimic p aminobenzoic acid (PABA) to hinder folate production, which is crucial for DNA replication and thereby inhibit bacterial growth. Sulfonamides have broad-spectrum activity and are vital in treating several bacterial infections, like urinary tract infections and respiratory infections. Though different antibiotics are currently available, sulfonamides are significant, especially for patients allergic to penicillin. This study aimed to discover novel sulfonamide like compounds from phytochemicals using a quantitative structure-activity relationship (QSAR) approach, a productive and cost-effective technique that allows the determination of the structural and biological similarities between the chemical compounds. The QSAR approach was implemented on the KNIME platform, version 5.2.5, along with cheminformatics extensions. Structural data for 407 phytochemicals, 18 FDA-approved sulfonamide drugs, and 21 control drugs were obtained from the ChEMBL database in SMILES format. These data were processed in KNIME to generate MACCS molecular fingerprints using the RDKit nodes. Three types of Machine learning (ML) models, Random Forest (RF), Artificial Neural Network (ANN), and Support Vector Machine (SVM), were trained to detect sulfonamide-like molecules, and the models were able to achieve a high prediction accuracy of 99.30%, 99.55%, and 99.33%, respectively. Both RF and ANN predicted Kaempferol-3-O-P-D-glucoside, a phytochemical obtained from Saraca indica, as a potential sulfonamide drug, while the SVM model did not identify any phytochemicals. The bioavailability of the predicted compound was confirmed by a drug likeliness test using Lipinski’s rule of five. In this study, Kaempferol-3-O-P-D-glucoside was identified as a promising compound for producing a novel sulfonamide antibiotic drug. However, further in-vitro and in-vivo experiments are required to confirm its potential to develop novel sulfonamides and utilise it for clinical purposes as an antibiotic. In addition, this study demonstrated the effectiveness of KNIME and ML models in computer-based drug discovery.
Effective corrosion barrier of cinnamon leaf oil incorporated polypyrrole layers for mild steel
(Postgraduate Institute of Science (PGIS), University of Peradeniya, Peradeniya, Sri Lanka, 2020-11-01) Palipana, P. W. G. K.; Revon, M. H. N.; Priyantha, N.
Mild steel, a type of steel commonly used in industry, is prone to corrosion under certain environmental conditions, which has limited its industrial applications, necessitating intensive study into corrosion prevention techniques. In recent years, conducting polymers and green corrosion inhibitors have been independently identified as corrosion inhibitors, and less consideration has been given over the past years on the combined effect of polymers and natural inhibitors. This study aimed to investigate the corrosion inhibition efficiency by cinnamon leaf oil embedded polypyrrole layers. The electrodeposition of polypyrrole on mild steel was employed using cyclic voltametric scans from -0.2 V to 1.0 V in oxalic acid medium and polymer-coated specimens were subsequently dipped in cinnamon leaf oil to incorporate into the polymer film. Under moderate acidic conditions of HCl medium, mass loss measurements of rectangular mild steel specimens embedded with cinnamon leaf oil, polypyrrole, and the combination of both over one-week period were obtained. The results revealed a superior corrosion inhibitory behaviour of the combined layer having the decreasing order of corrosion inhibition efficiency: polypyrrole and cinnamon leaf oil > polypyrrole > cinnamon leaf oil. Polarization resistance determined by electrochemical impedance spectroscopy, a more reliable method, further supports the strong corrosion inhibitory action of the combined layer on mild steel when compared to polypyrrole and cinnamon leaf oil alone. Open circuit potential measurements also indicate a lower corrosion rate when mild steel specimens are coated with the polymer and cinnamon leaf oil.
Antioxidant, antidiabetic, cytotoxic and phytotoxic properties of two medicinal plants, Buchanania axillaris and Curcuma longa
(Postgraduate Institute of Science (PGIS), University of Peradeniya, Sri Lanka, 2024-11-01) Premasiri, H. A. K. D.; Siriwardhane, U.; Piyasena, N. P.; Adikaram, N. K. B.; Marikkar, N.; Jayasinghe, U. L. B.
Medicinal plants are a rich source of bioactive compounds with potential applications in pharmaceuticals, nutraceuticals, and agrochemicals. This study aimed to assess the bioactivities of extracts from Buchanania axillaris leaves and rhizomes of Curcuma longa. They were collected domestically within the Kandy District, Sri Lanka. Plant material was air-dried and ground to obtain a homogenous powder using a grinder. The powdered samples were extracted into methanol by sonicating for 30 min. This procedure was repeated twice, and the filtrates were combined and evaporated to dryness using a rotary evaporator. The crude extracts were evaluated for antioxidant activity using triplicates for 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay, enzyme inhibitory activity against α-amylase, α-glucosidase, and lipase, and 10 nauplii for cytotoxicity through the brine shrimp lethality assay, and 10 seeds for phytotoxicity by the lettuce seed germination assay. The results demonstrated that B. axillaris exhibited potent antioxidant activity, with an IC₅₀ value of 0.03 ± 0.07 mg/L for DPPH radical scavenging activity, than C. longa (61.49 ± 0.57 mg/L). Positive control was ascorbic acid (IC₅₀ = 3.47 ± 0.45 mg/L). Both extracts displayed α-glucosidase inhibitory activity, with 100% inhibition at 1000 mg/L, indicating their potential in managing diabetes. Curcuma longa showed moderate α-amylase inhibitory activity, with an IC₅₀ of 465.81 ± 23.31 mg/L (Positive Control-Acarbose IC₅₀ = 8.87 ± 1.21 mg/L). Neither extract exhibited significant lipase inhibitory effects within the tested concentration range. The cytotoxicity assay revealed potent brine shrimp lethality for C. longa, with a LC₅₀ of 20.01 ± 3.14 mg/L, against the positive control, atropine, LC₅₀ = 88.60 ± 8.11 mg/L. Buchanania axillaris exhibited phytotoxic potency with IC₅₀ values of 520.97 ± 15.14 mg/L and 665.14 ± 20.54 mg/L, while C. longa exhibited IC₅₀ values of 625.29 ± 12.76 mg/L and 586.53 ± 9.32 mg/L, compared to the positive control, abscisic acid (IC₅₀ = 1.46 ± 0.19 mg/L and 1.85 ± 0.31 mg/L) for root and shoot inhibition, respectively, suggesting potential applications as natural herbicides. The findings indicate promising bioactivities of B. axillaris and C. longa extracts, suggesting further exploration for potential applications in pharmaceuticals, nutraceuticals, and agriculture.
Boosting Penicillin activity using Coriandrum sativum seed extracts against Methicillin-resistant Staphylococcus aureus
(Postgraduate Institute of Science (PGIS), University of Peradeniya, Sri Lanka, 2024-11-01) Karunathilaka, S.; Warnakula, P.; Darshana, D.
The rise of antibiotic resistance, particularly among methicillin-resistant Staphylococcus aureus (MRSA), underscores the urgent need for novel strategies to enhance antibiotic efficacy. Coriandrum sativum L. is an aromatic herbaceous plant with traditional medicinal uses. This study investigated the ability of C. sativum seed extracts to boost penicillin activity against MRSA. The primary objective was to evaluate the antibacterial activity of crude seed extracts of C. sativum against pathogenic bacteria and compare their effectiveness alone and in combination with penicillin against MRSA. Dried C. sativum seeds were sequentially extracted with hexane, dichloromethane, ethyl acetate, methanol, and water using a Soxhlet apparatus, and their antibacterial activity was determined using the disk diffusion method. Ciprofloxacin (2 mg/mL) and DMSO were used as positive and negative controls, respectively. The interaction between seed extracts and penicillin was tested using MRSA as the model organism. Results showed that hexane, dichloromethane, ethyl acetate, and methanol extracts significantly inhibited the growth of Staphylococcus aureus (ATCC 25923), MRSA (clinical isolate) and Escherichia coli (ATCC 25922), with inhibition zone diameters (IZD) exceeding 10 mm, while the aqueous extract showed limited activity (IZD > 23 mm), inhibiting only E. coli. None of the extracts was effective against Pseudomonas aeruginosa (ATCC 27853). Ciprofloxacin inhibited all the tested organisms, showing an IZD >32 mm, while DMSO was inactive against all the tested organisms. Notably, combining half and one-fourth the concentration of penicillin's minimum inhibitory concentration (MIC) with ethyl acetate extract of C. sativum also at half MIC demonstrated enhanced inhibition of MRSA (IZD > 7 mm). This interaction suggests that C. sativum extracts can potentiate penicillin's efficacy as a promising strategy to counteract antibiotic resistance. The study concludes that seed extracts of C. sativum possess notable antibacterial activity and can be used to enhance the efficacy of penicillin against MRSA. Further research should focus on isolating and characterizing the active phytochemicals in C. sativum, investigating their interactions with other antibiotics to develop formulations to incorporate C. sativum extracts into clinical applications.
Preliminary study on evaluating the carbon stocks prior to seagrass restoration in Sinna Arichchal, Kalpitiya, Sri Lanka
(Postgraduate Institute of Science (PGIS), University of Peradeniya, Sri Lanka, 2024-11-01) Gunasiri, W. S. P.; Munasinghe, C. S.
Seagrass meadows serve as significant carbon sinks, playing a crucial role in climate change mitigation. They capture CO2 through photosynthesis, forming organic matter in tissues and sediments, which enhances carbon storage via sediment stabilization. The reduction of seagrass leads to decreased carbon sequestration, exacerbating climate change impacts. This ongoing study focuses on establishing a one-hectare seagrass meadow and evaluating its impact on blue carbon storage. Prior to restoration, four 60 cm-deep soil core samples were collected from both the donor and the restoration sites at Sinna Arichchal Island, Kalpitiya, Sri Lanka, using a Russian peat auger. Each core sample was divided into six 10 cm subsamples (24 total subsamples) based on depth and analysed using the loss-on-ignition method to quantify total organic carbon content. The mean total organic carbon percentage was compared using the t-test, revealing a higher percentage at the donor site (7.28 ± 2.89) than at the restoration site (6.71 ± 3.40), suggesting a potentially greater carbon content at the donor site. However, this difference was not statistically significant (t = 0.45, p = 0.667). The higher carbon percentage at the donor site may be attributed to the presence of seagrass, less disturbance, and better preservation. Further sampling and analysis are necessary to confirm this trend with statistical significance. To ensure the successful establishment of the restored seagrass, regular monitoring of growth, health, and environmental conditions is essential. Post-restoration surveys will analyse and compare sediment samples to assess changes in blue carbon stocks before and after restoration, determining the extent of potential improvement in carbon storage.
In-vitro cytotoxic activity of Elaeocarpus serratus and Artocarpus heterophyllus plant leaf extracts
(Postgraduate Institute of Science (PGIS), University of Peradeniya, Sri Lanka, 2024-11-01) Virajini, M. P. T.; Bandara, M. D.; Jayasooriya, P.; Samarakoon, K. W.; Kuruppu, A. I.
Cancer is one of the main causes of disease and death worldwide, hence the continuous search for new therapeutic agents is essential. This study examined the ability of leaf extracts of Elaeocarpus serratus (“Veralu”) and Artocarpus heterophyllus (Jackfruit) to kill cancer cells in-vitro. A hot aqueous extract, macerated aqueous and macerated methanol extracts were prepared with dried mature leaf samples, which were then tested using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay for cytotoxic activity against two human cancer cell lines; MCF-7 (breast cancer) and HepG2 (liver cancer). The results indicated that, in a dose-dependent manner, both extracts showed notable cytotoxic effects. Artocarpus heterophyllus extracts exhibited lower IC₅₀ values when compared to E. serratus (p < 0.0001) as 27.48 μg/mL, 18.63 μg/mL, and 5.67 μg/mL for hot water, macerated aqueous, and methanol extracts, respectively, against the MCF-7 cell line. The A. heterophyllus leaf extract showed low IC₅₀ values against the HepG2 cell line but the values for some extracts were much higher compared to the MCF7 cell line. The IC₅₀ values were 22.07 μg/mL, 47.07 μg/mL and 54.01 μg/mL for hot water, macerated water, and macerated methanol extracts, respectively. The E. serratus leaf extracts showed somewhat less potent results for both cell lines, whereas the most potent result was for the aqueous macerated extract against the MCF7 cell line with IC₅₀ of 90.59 μg/mL. The methanol extract of A. heterophyllus showed anti-inflammatory activity with an IC₅₀ of 32.94 μg/mL in the Human Red Blood Membrane Stabilization assay. In comparison, the Ibuprofen standard showed an IC₅₀ of 4.92 μg/mL. The same extract also exhibited an IC₅₀ of 4.07 μg/mL in the ABTS assay (2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid)) while the ascorbic acid standard showed an IC₅₀ of 0.30 μg/mL. These results indicate that Artocarpus heterophyllus leaf extract could be promising as a potential source of anti-cancer compounds; however, more research, including in-vivo studies and the identification of the active components, is needed to fully understand the therapeutic potential.
Broad-spectrum cytotoxic potential of Zanthoxylum rhetsa against varied cancer cell lines
(Postgraduate Institute of Science (PGIS), University of Peradeniya, Sri Lanka, 2024-11-01) Jayasinghe, M. R.; Samarakoon, K. W.; Kuruppu, A. I.
The study of phytochemicals in medicinal plants is becoming popular due to their numerous pharmacologic effects. With their molecular level processes, natural compounds with anticancer properties can target reactive oxygen species signalling, induce apoptosis, reverse multidrug resistance, and produce anti-malignancy medicines. The objective of this study was to evaluate the broad-spectrum cytotoxic potential of four distinct extracts of plant parts of Zanthoxylum rhetsa (Indian prickly ash) against a variety of human cancer cell lines. The dried-plant powder of the leaf, bark, thorn, and bark-thorn was extracted using methanol. The cytotoxicity was determined against four cancer cell lines by the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay, and subsequently, the cancer cell colony formation ability was determined by clonogenic assay. The resulting IC50 values of all four extracts ranged from 0.006 ± 0.002 mg/mL to 0.014 ± 0.017 mg/mL against the RD sarcoma cell line, 0.004 ± 0.002 mg/mL to 0.014 ± 0.003 mg/mL against the DLD1 colon cancer cell line, 0.005 ± 0.001 mg/mL to 0.01 ± 0.004 mg/mL against the MCF7 breast cancer cell line, 0.018 ± 0.001 mg/mL to 0.035 ± 0.004 mg/mL against the HeLa cervical cancer cell line and 0.015 ± 0.004 mg/mL to 0.030 ± 0.009 mg/mL against the Vero cell line (non-cancerous). The colony-forming capacity of the extracts decreased with increasing IC₅₀ concentrations. A remarkable inhibition of colony formation was observed with the thorn extract at 5 × IC₅₀ against the HeLa cell line with zero surviving cancer colonies. Similarly, the thorn extract showed potent cell toxicity against the RD cell line as well, with a low survival fraction of 9.9%. Previous studies have identified alkaloids, flavonoids, and phenolic compounds in Z. rhetsa as key contributors to its cytotoxic effects, potentially through apoptosis induction and tumour growth inhibition. These encouraging findings in vitro bolster the potential of Z. rhetsa as a natural source for the development of novel medicinal compounds against cancer.
Insecticidal potentials of plant powders against pests of stored grains; Sitophilus oryzae (rice weevil) and Callosobruchus maculatus (cowpea weevil) in Sri Lanka
(Postgraduate Institute of Science (PGIS), University of Peradeniya, Sri Lanka, 2024-11-01) Anuradha, G. N. P. V.; Rajapaksha, W. R. G. W. N.; de Silva, W. A. P. P.; Weeraratne, T. C.
Due to the negative impacts of synthetic insecticides, there is a pressing need for alternative, eco-friendly approaches to control pests of stored grains. This study aimed to investigate the effectiveness of powders of Syzygium aromaticum leaves, Allium sativum cloves, and Olax zeylanica leaves against Sitophilus oryzae and Callosobruchus maculatus, pests of stored grains. Smooth plant powder was prepared by grinding the dried leaves/cloves. Hundred healthy adults of each pest species (25 per replicate) from laboratory stock cultures were exposed to five concentrations (1%, 2%, 4%, 6%, and 8% w/w) of each plant powder, mixed in 100 g of disinfected grains in plastic containers covered with muslin cloth, and mortalities were recorded after every 24 hrs until 12 days. Log-probit curves were constructed, and the lethal concentration (LC₅₀) and lethal time (LT₅₀) required to kill 50% of the population were obtained by regression analysis. When treated with ≥ 2% O. zeylanica, both S. oryzae and C. maculatus exhibited 100% mortality within 24 hrs, and the LT₅₀ values were 10 hrs and 8 hrs, respectively. Allium sativum and S. aromaticum treatments demonstrated relatively low toxicity, as indicated by their high LT₅₀ values, with 12 days required to achieve 100% mortality in both pest species. Although the toxicity effect between A. sativum and S. aromaticum against S. oryzae was not significant (p = 0.806), S. aromaticum showed higher toxicity against C. maculatus, with a LC₅₀ of 0.85% and a LT₅₀ of 1.4 days at 2%, compared to A. sativum, which had a LC₅₀ of 4.9% and a LT₅₀ of 3.4 days at 2%. However, 100% mortality of C. maculatus was observed within 24 hrs when a high concentration, i.e. 8%, was used. The overall results revealed an effective toxicity against both pests in the order of O. zeylanica > S. aromaticum > A. sativum. Further studies would explore the repellence and synergistic effects of these plant products for pest management.
Effect of skin microbial composition of cattle on biting preference of mosquitoes
(Postgraduate Institute of Science (PGIS), University of Peradeniya, Sri Lanka, 2024-11-01) Baddevithana, B. V. D. S.; Wijesundara, W. M. S. H.; de Silva, W. A. P. P
Host selection and biting site preference of blood-feeding insects depend on the host-derived signals, specifically from volatile compounds produced by the metabolic activities of skin microbes. This study aimed to examine the effect of the skin microbiota composition of cattle (Bos sp.) on the biting site preference of mosquitoes. Mosquito biting behaviour was observed on three adult cattle across two study locations in the Kandy District (Pallethalawinna, and Sandasiri Dunuwila area), from 1700 h to 2000 h, from July to September 2023. Each cow was sampled six times, and a total of 18 observations were made to record the number of mosquitoes landing on different body sites of cattle. Skin microbial samples were collected from different body sites using sterile cotton swabs. Collected skin microbes were cultured in nutrient broth for 24 hrs. Nutrient agar plates were prepared for different dilutions of the bacterial cultures to visualize the bacterial composition. Isolated colonies on agar plates were identified based on morphological differences. Results indicated a significant difference in mosquito biting preferences across different body parts of cattle (p = 0.001). Mosquitoes most preferred the area above the knee [32.5% (249 mosquitoes)], followed by the moderately preferred neck [8.0% (61 mosquitoes)]. The thigh area was least preferred [3.5% (27 mosquitoes)], while the nostril-to-eye region was not bitten by any mosquitoes. The microbiome composition included 18 distinct bacterial morphologies across the four body sites. Five morphologies were unique to the most preferred site, while another five were found in the least preferred sites. Two morphologies were common across all four sites. Additionally, two unique morphologies were identified in moderately preferred and none-bitten sites. These findings revealed a varied mosquito-biting preference with the skin microbiome composition.
Probing students’ higher-order thinking skills in grade 13 chemistry: a case study from Kandy education zone, Sri Lanka
(Postgraduate Institute of Science (PGIS), University of Peradeniya, Sri Lanka, 2024-11-01) Visvanathan, S.; Madawala, H. M. S. P.; Bandara, A. M. R. S.; Welegedara, A. P.
Fostering higher-order thinking skills (HOTS) in chemistry education is essential for developing students’ analytical, problem-solving, and creative abilities. Recognizing this necessity, the revised chemistry syllabus implemented in 2017 by the Ministry of Education, Sri Lanka, endeavoured to integrate HOTS through various teaching-learning strategies. This research aims to assess the present status of HOTS in Grade 13 students across six public schools in the Kandy Zone of Education, Sri Lanka. A descriptive research design with a quantitative framework was employed, and a HOTS evaluation tool was developed following Anderson and Krathwohl’s revised Bloom's Taxonomy, 2001. This tool consisted of 12 two-tier multiple-choice (TTMC) questions and three double-statement questions designed to evaluate students' understanding of chemical concepts with reasoning related to the three levels; Analysis, Evaluation and Creation. The validity and reliability of the instrument were established through expert judgment and Cronbach’s alpha. A convenient sample of 133 (45 male and 88 female) students from the designated schools underwent the assessment. Descriptive statistics revealed that over 90% of the students answered less than 50% of the questions correctly. In terms of the three levels of HOTS, the correct responses were 26.8%, 24.4%, and 17.5% for tiers 1 and 2, and it was 44.5%, 37.3% and 36.3% for tier 1 only. The mean values for those three levels were 1.61, 1.22, and 0.70 for tiers 1 and 2 and 2.67, 1.86, and 1.45 for tier 1, respectively. The findings indicate a lack of students’ skills in all three levels of HOTS. A higher percentage of correct responses for tier 1 compared to tier 2 suggests that students are relying more on rote memorization than on a deeper understanding of chemistry concepts. The study highlights the urgent need for teaching-learning interventions to enhance HOTS among students and sets the stage for further studies.
Demographic factors on clinically important microflora in denture biofilms using PCR technique
(Postgraduate Institute of Science (PGIS), University of Peradeniya, Sri Lanka, 2024-11-01) Jayakody, S. L.; Rajapakse, R. G. S. C.; Wimalarathna, A. A. A. K.; Jayatilake, J. A. M. S.
Edentulism, the loss of natural teeth in humans, is a pressing global public health issue, especially affecting older adults. Removable complete dentures commonly address this problem but are also prone to microbial colonization, forming biofilms. These biofilms act as reservoirs for potentially pathogenic microorganisms, posing risks of systemic and localized diseases. This study employed a culture-independent PCR-based method to investigate the prevalence of clinically significant microorganisms in complete denture biofilms and the impact of demographic factors on their prevalence. Samples were collected from 35 denture wearers without any diagnosed clinical implications at the Dental Teaching Hospital, Peradeniya, with relevant demographic data gathered via questionnaires. The study included 10 male and 25 female participants, aged 56-85, who had used complete dentures for over one year. DNA was directly extracted from the biofilm samples scraped from the adherent denture surface. PCR using species-specific primers targeting the 16S rRNA gene for bacteria and the KER1 gene for Candida albicans was performed. Streptococcus mutans (28/35), Porphyromonas gingivalis (24/35), Helicobacter pylori (8/35), Escherichia coli (25/35), Candida albicans (11/35), and Staphylococcus aureus (29/35) were identified within the biofilms. Statistical analyses revealed associations between demographic factors (sex, age, denture age, and hygiene) and microbial colonization. Visual assessment of denture plaque accumulation was used to evaluate denture hygiene. Significant associations were found between poor denture hygiene and higher prevalence of S. mutans, H. pylori, P. gingivalis, and E. coli (χ² of 5.62, 9.35, 4.81 and 12.45, respectively), as well as between older denture age and increased presence of S. mutans, P. gingivalis, and H. pylori (χ² of 11.22, 5.74 and 5.1, respectively). A positive correlation was noted between denture age and hygiene (r = 0.47, p < 0.05), while sex showed no significant association with denture hygiene (r = 0.03, p > 0.05). These findings emphasize the importance of regular denture maintenance and hygiene in preventing microbial-related complications among older adults.
Fostering education for environmental sustainability: level of competencies on reducing environmental pollution of junior secondary students in Sri Lanka
(Postgraduate Institute of Science (PGIS), University of Peradeniya, Sri Lanka, 2014-11-01) Liyanage, T. I. S. S.
Education for Environmental Sustainability (EES) aims to develop students' sensitivity, awareness, knowledge, attitudes, skills, and practices related to the environment and the sustainable use of its resources. It not only empowers students on environmental concerns but also connects them to more sustainable lifestyles, enabling them to become environmentally literate. This cross-sectional survey was conducted to assess the environmental literacy of junior secondary students (Grades 6 to 9) in selected Sri Lankan schools. The aim of the study was to determine students' competency levels in reducing environmental pollution. The sample included 442 students from three districts in the Western Province (Colombo, Gampaha, and Kalutara), selected using random stratified sampling techniques. A questionnaire with multiple-choice questions was used as the research instrument. Students' competency in organic farming, eco-friendly energy sources, reducing/recycling, and judgment on eco-friendly practices was assessed. Competency was measured by students' ability to identify and analyse environmental issues, ask relevant questions, evaluate and make personal judgments, and use evidence and knowledge to defend their positions. The findings revealed that students' competency levels in the focused areas improved with more effective EES implementations in school education. Students in the Colombo District recorded the highest competency level (μ = 0.55 ± 0.26), while the lowest was recorded in the Gampaha District (µ = 0.53 ± 0.26). Competency varied from 0 to 1 across all three districts. Grade 8 students showed the highest competency (μ = 0.55 ± 0.22), while Grade 6 students recorded the lowest (µ = 0.48 ± 0.28). A significant association was observed between the student category and organic farming (p < 0.05), as well as reducing/recycling and willingness to engage in pollution reduction activities (p < 0.05). There were significant variations across districts and among the three grades (p < 0.05). In conclusion, the findings underscore the critical role of EES in enhancing students' environmental literacy and greater awareness and promoting active participation in sustainable practices, paving the way for a more environmentally responsible generation.
Menstrual hygiene among school children in South Asia: awareness, practices and constraints
(Postgraduate Institute of Science (PGIS), University of Peradeniya, Sri Lanka, 2024-11-01) Jayasundara, A. A. D.; Madawala, H. M. S. P
Menstrual hygiene practices among adolescent girls in South Asia are influenced by a complex array of factors, leading to disparities and challenges in proper menstrual management. The aim of this study was to explore the dynamics of menstrual hygiene among school children in South Asia and identify barriers affecting their menstrual health. The specific objectives included assessing the level of awareness, current practices, and constraints related to menstrual hygiene. A systematic review of 15 research articles, sourced from databases such as Google Scholar, ResearchGate, PubMed, and Web of Science, was conducted. The review specifically focused on school children in South Asia, addressing aspects of their awareness, practices and constraints on menstrual hygiene. Out of these 15 articles, 10 provided a comprehensive analysis of awareness, practices, and constraints related to menstrual hygiene. Among these, seven studies were conducted in India, one in Pakistan, and two in Nepal. Two articles solely discussed awareness, with one article each focusing exclusively on practices, awareness and constraints. The findings suggest that most South Asian school girls receive information about menstruation prior to menarche and that mothers are the main providers of this information. However, the articles consistently highlight the lack of comprehensive knowledge regarding menstrual cycles, secondary sexual characteristics, and reproductive health among them. Many girls do not adhere to the recommended frequency of changing sanitary products every 3-4 hours, which can lead to various health complications, including an increased risk of reproductive tract infections (RTIs), skin irritation, and other hygiene-related issues. Additionally, burning appears to be the most common method of disposing used products. Cultural and religious taboos impose significant restrictions on menstruating girls, compounded by inadequate hygiene facilities such as gender-segregated toilets and washing and changing amenities in schools. In conclusion, the study calls for comprehensive menstrual health education, affordable products, and cultural shifts to improve menstrual management and well-being for South Asian female students.
Effect of different teaching methods on students’ performance in the electronic section of G.C.E. ordinary level science: case study of students from Nuwara Eliya district, Sri Lanka
(Postgraduate Institute of Science (PGIS), University of Peradeniya, Sri Lanka, 2024-11-01) Weerasingha, S. N.; Senevirathne, K. S. H. M. V. W. W.
The majority of science students week in the electronic section of the science curriculum prepared for the General Certificate Examination of Ordinary Level (G.C.E. O/L) in Sri Lanka. The primary objective of this study was to evaluate student performance in the electronics unit of the Grade 11 science curriculum. The four different teaching methods were comparatively evaluated for their effectiveness. The identification of suitable teaching methods, determination of subject performance, and evaluation of the relationship between teaching methods and performance were the specific objectives of this study. A quasi experimental design with a quantitative approach was used for the study. A sample of 113 Grade 11 students from two schools in the Nuwara Eliya District was selected using non-randomized sampling. The electronic unit of the science curriculum of Grade 11 was taught to four parallel classes using four different teaching methods: guided discovery method, lecture method, teacher demonstration method and simulation method. The performance test scores obtained were analysed using SPSS software. The findings indicated a significant difference between teaching methods and student achievements (p = 0.001). Among the four teaching methods, the simulation method was identified as the best method. Both male and female students showed preferences for the simulation method, suggesting its importance in teaching the electronic section in the Grade 11 science curriculum.
Teachers’ role in enhancing students’ academic performance and behaviours
(Postgraduate Institute of Science (PGIS), University of Peradeniya, Sri Lanka, 2024-11-01) Hakeem, M. A. A.; Jayasuriya, K. M. G. G.
Teaching has been considered a noble profession ever since human civilization began. Apart from imparting knowledge, teachers play multiple roles. This review investigated the role of teachers in students’ academic performance, attitudes, and behaviours. The information was collected from review articles, conference papers, master's theses, and doctoral dissertations published between 2000 and 2023. Additionally, thirty research papers were selected from Google Scholar, PubMed, and ResearchGate. The literature reveals a lack of sufficient studies conducted in Sri Lanka, as the majority of these studies (90%) were carried out in other countries. Data were analysed through content analysis. According to the findings, teacher-student interactions, specific teaching practices, motivation toward learning, and teachers' organizational techniques were identified as the main factors affecting students’ academic performance, attitudes, and behaviours. Teacher-student interactions were found to be the most critical factor (mentioned in 33% of the articles) that shapes student behaviour and attitudes. Nearly 23% of articles emphasized that both teaching strategies and the motivational support received from teachers are important for student performance. A few research articles (20%) highlighted the impact of teachers’ organizational abilities on students’ attitudes and performance. These findings provide valuable insights for enhancing teacher training programs.
Effect of biofilm biofertilizers on the water use efficiency of lowland rice (Oryza sativa L.)
(Postgraduate Institute of Science (PGIS), University of Peradeniya, Sri Lanka, 2024-11-01) Epa, V. G. T. A.; Gunawardhana, H. M. C. J.; Ekanayake, S. N. B.; Premarathna, M.; Seneviratne, G.; Seneweera, S.
High water consumption in rice (Oryza sativa L.) cultivation challenges sustainable agriculture, particularly in the face of climate change. Biofilm biofertilizer (BFBF) has been reported to improve soil organic matter and offers the potential to improve water conservation in agroecosystems. This study aimed to investigate the impact of BFBF on the water usage of rice by conducting a pot experiment using two varieties: wetland (At 314) and upland (Bg 251). Two fertilizer practices were tested: (a) chemical fertilizer (CF) at 340 kg NPK ha⁻¹, recommended by the Department of Agriculture, Sri Lanka, and (b) BFBF at 225 kg NPK ha⁻¹ + 2.5 L BFBF ha⁻¹. Three water regimes were applied: (a) flooded, (b) field capacity, and (c) 65% field capacity, using three-factor factorial completely randomized design with three replicates. The amounts of water required to maintain the water regimes were recorded daily. Total water usage, net assimilation rate (NAR), relative growth rate (RGR), and 100-grain weight were measured. Data were analysed using a factorial ANOVA followed by Tukey’s HSD test. The results highlighted that water usage in the wetland variety was significantly (p < 0.05) reduced by 8-12% with the application of BFBF, while water usage remained comparable between both fertilizer practices in the upland variety. Both varieties showed comparable NAR and RGR across fertilizer practices. The 100-grain weight decreased with increasing water stress in all varieties and fertilizer practices. Results suggest that water usage was comparable in both CF and BFBF practices in upland rice. In wetland rice, BFBF application significantly reduced water usage without affecting grain yield, indicating a promising strategy for efficient water management in agriculture. Further research under field conditions with larger plot sizes is recommended to confirm these results.
Demographic factors on clinically important microflora in denture biofilms using pcr technique
(Postgraduate Institute of Science (PGIS), University of Peradeniya, Sri Lanka, 2024-11-01) Jayakody, S. L.; Rajapakse, R. G. S. C.; Wimalarathna, A. A. A. K.; Jayatilake, J. A. M. S.
Edentulism, the loss of natural teeth in humans, is a pressing global public health issue, especially affecting older adults. Removable complete dentures commonly address this problem but are also prone to microbial colonization, forming biofilms. These biofilms act as reservoirs for potentially pathogenic microorganisms, posing risks of systemic and localized diseases. This study employed a culture-independent PCR-based method to investigate the prevalence of clinically significant microorganisms in complete denture biofilms and the impact of demographic factors on their prevalence. Samples were collected from 35 denture wearers without any diagnosed clinical implications at the Dental Teaching Hospital, Peradeniya, with relevant demographic data gathered via questionnaires. The study included 10 male and 25 female participants, aged 56-85, who had used complete dentures for over one year. DNA was directly extracted from the biofilm samples scraped from the adherent denture surface. PCR using species-specific primers targeting the 16S rRNA gene for bacteria and the KER1 gene for Candida albicans was performed. Streptococcus mutans (28/35), Porphyromonas gingivalis (24/35), Helicobacter pylori (8/35), Escherichia coli (25/35), Candida albicans (11/35), and Staphylococcus aureus (29/35) were identified within the biofilms. Statistical analyses revealed associations between demographic factors (sex, age, denture age, and hygiene) and microbial colonization. Visual assessment of denture plaque accumulation was used to evaluate denture hygiene. Significant associations were found between poor denture hygiene and higher prevalence of S. mutans, H. pylori, P. gingivalis, and E. coli (χ² of 5.62, 9.35, 4.81 and 12.45, respectively), as well as between older denture age and increased presence of S. mutans, P. gingivalis, and H. pylori (χ² of 11.22, 5.74 and 5.1, respectively). A positive correlation was noted between denture age and hygiene (r = 0.47, p < 0.05), while sex showed no significant association with denture hygiene (r = 0.03, p > 0.05). These findings emphasize the importance of regular denture maintenance and hygiene in preventing microbial-related complications among older adults.
Endophytic diazotrophs maintain chlorophyll content in organic rice under modern biofilm-based bio-organo-mineral fertilizer practice
(Postgraduate Institute of Science (PGIS), University of Peradeniya, Sri Lanka, 2024-11-01) Jayakody, K.; Pathirana, R.; Premarathna, M.; Seneviratne, G.; Madawala, H. M. S. P.; Nanayakkara, B. S.
Photosynthesis is crucial for food and oxygen production on Earth. Plant endophytes improve photosynthetic efficiency by boosting chlorophyll content, which increases with biofilm biofertilizer (BFBF) application in rice (Oryza sativa L.). This study aimed to investigate this relationship through field experiments in Anuradhapura, Puttalam, Ampara, and Polonnaruwa districts. Three treatments were employed: (a) Bio-organo-mineral fertilizer (BOMF) practice (500 kg NPK BOMF/ha + 2.5 L BFBF/ha), (b) Chemical fertilizer (CF) practice (340 kg CF NPK/ha), and (c) control (no fertilizer), using a randomized complete block design with three replicates. Plant samples were collected at the 50% flowering stage and analysed for total counts of endophytic bacteria (TEB), endophytic diazotrophs (ED), endophytic fungi (EF), and leaf chlorophyll content. One-way ANOVA and Tukey’s HSD test were performed for mean comparisons and correlation analysis. Results revealed that the highest TEB and ED were observed in the control, and they were significantly (p < 0.05) reduced with the CF alone application. The BOMF practice showed significantly (p < 0.05) higher TEB and ED compared to the CF practice, indicating a facilitative effect of restoring the plant microbiome. The EF was significantly (p < 0.05) higher in the BOMF practice than the other two practices. Chlorophyll content was comparable across all three treatments. Chlorophyll content was negatively correlated with TEB (r = -0.810, p = 0.008) and EF (r = -0.881, p = 0.002) only in the CF practice, indicating a potential negative impact of CF on endophytes. It can be concluded that applying BOMF could increase the abundance of ED, TEB, and EF, thereby increasing the ability of plants for diazotrophic N₂ fixation and maintaining the chlorophyll content, even without CFs. Further research using the ¹⁵N isotopic technique is recommended to confirm the relative contributions of fertilizer-N and fixed-N for chlorophyll production in rice.
Leveraging large language models for region-specific focus in pulmonary embolism detection
(Postgraduate Institute of Science (PGIS) University of Peradeniya, Sri Lanka, 2024-11-01) Herath, H. M. S. K. B.; Gunathilake, P. M. P. C.; Roshan G. Ragel
Pulmonary embolism (PE), characterized by the blockage of lung arteries due to blood clots, is a critical and potentially life-threatening condition that demands precise and timely diagnosis. Manual readings of medical images can sometimes lead to misdiagnoses, especially when the image quality is not ideal, putting patients at serious risk. Traditional PE detection models rely on image data alone, limiting their accuracy and interpretability. In the evolving field of deep learning for medical image analysis, there is significant potential to improve PE detection through advanced methodologies. The study aimed to enhance the detection of PE by integrating Large Language Models (LLMs) with Data efficient image Transformer architecture (DeiT), which addresses some of the key limitations of traditional Vision Transformers. This multimodal approach is novel and shows promising results. For this research Down sampled RSNA data set was used to represent all the available positive studies and equal number of negative studies. The traditional CNN approach achieved over 76.4% accuracy and the transformer-based approach achieved over 79.7% accuracy, however, this proposed method achieved an impressive accuracy of over 91.2%. These findings revealed that this integrated approach significantly enhances both the accuracy and interpretability of PE detection models. The use of attention mechanisms with Vision Transformers showcases superior capabilities compared to traditional CNN-based approaches, making a notable impact on medical image analysis and disease diagnosis. This advancement highlights the broader applicability of this method, enhancing detection accuracy and reducing processing time, ultimately leading to better patient outcomes.

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