{"title":"Evolving research perspectives on microplastic pollution: A focus on Sri Lanka in comparison to the South and Southeast Asian region","authors":"M. Vithanage","doi":"10.4038/cjs.v53i2.8382","DOIUrl":"https://doi.org/10.4038/cjs.v53i2.8382","url":null,"abstract":"No abstract available","PeriodicalId":9894,"journal":{"name":"Ceylon Journal of Science","volume":"61 S1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140721874","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
W.R.G.W.N. Rajapaksha, W.A.P. P. De Silva, T. Weeraratne
Botanical extracts offer sustainable and eco-friendly alternatives to synthetic insecticides for managing insect pests, including mosquitoes. This research focuses on the potential of ethanolic garlic extract as a larvicide against Aedes albopictus and Culex quinquefasciatus mosquito species in Sri Lanka. Third to early fourth instar larvae were exposed to six concentrations of ethanolic garlic extract (ranging from 5 to 250 ppm) for 72 hours to assess efficacy. The experiment, repeated four times with controls, monitored daily mortalities. Lethal concentrations required to eliminate 50% (LC50) and 90% (LC90) of larvae at 24, 48, and 72 hours were determined through regression analysis. A phytochemical analysis was conducted to assess the compounds present in the garlic extract. Positive correlations were observed between garlic concentration and mortality percentages during each exposure period for both Ae. albopictus and Cu. quinquefasciatus larvae. LC50 values for Ae. albopictus larvae were 45.5 ppm, 28.0 ppm, and 14.4 ppm at 24, 48, and 72 hours respectively, with corresponding LC90 values of 140.0 ppm, 91.0 ppm, and 42.9 ppm. For Cu. quinquefasciatus larvae, LC50 values were 26.3 ppm, 9.4 ppm, and 4.4 ppm, while LC90 values were 169.8 ppm, 30.7 ppm, and 17.6 ppm for the same exposure periods. The garlic ethanolic extract retained its flavonoids, saponins, and reducing sugars even after a year of extraction, as revealed by phytochemical analysis. The study underscores the potent toxicity of garlic extract against mosquito larvae, with LC50 values below 50 ppm. These findings highlight the potential of garlic extracts as effective larvicides for combating mosquito vectors, contributing to environmentally friendly pest management strategies.
{"title":"Comparative evaluation of the effect of phytochemicals of garlic (Allium sativum) ethanolic extract against Aedes albopictus and Culex quinquefasciatus mosquitoes in Sri Lanka","authors":"W.R.G.W.N. Rajapaksha, W.A.P. P. De Silva, T. Weeraratne","doi":"10.4038/cjs.v53i1.8230","DOIUrl":"https://doi.org/10.4038/cjs.v53i1.8230","url":null,"abstract":"Botanical extracts offer sustainable and eco-friendly alternatives to synthetic insecticides for managing insect pests, including mosquitoes. This research focuses on the potential of ethanolic garlic extract as a larvicide against Aedes albopictus and Culex quinquefasciatus mosquito species in Sri Lanka. Third to early fourth instar larvae were exposed to six concentrations of ethanolic garlic extract (ranging from 5 to 250 ppm) for 72 hours to assess efficacy. The experiment, repeated four times with controls, monitored daily mortalities. Lethal concentrations required to eliminate 50% (LC50) and 90% (LC90) of larvae at 24, 48, and 72 hours were determined through regression analysis. A phytochemical analysis was conducted to assess the compounds present in the garlic extract. Positive correlations were observed between garlic concentration and mortality percentages during each exposure period for both Ae. albopictus and Cu. quinquefasciatus larvae. LC50 values for Ae. albopictus larvae were 45.5 ppm, 28.0 ppm, and 14.4 ppm at 24, 48, and 72 hours respectively, with corresponding LC90 values of 140.0 ppm, 91.0 ppm, and 42.9 ppm. For Cu. quinquefasciatus larvae, LC50 values were 26.3 ppm, 9.4 ppm, and 4.4 ppm, while LC90 values were 169.8 ppm, 30.7 ppm, and 17.6 ppm for the same exposure periods. The garlic ethanolic extract retained its flavonoids, saponins, and reducing sugars even after a year of extraction, as revealed by phytochemical analysis. The study underscores the potent toxicity of garlic extract against mosquito larvae, with LC50 values below 50 ppm. These findings highlight the potential of garlic extracts as effective larvicides for combating mosquito vectors, contributing to environmentally friendly pest management strategies.","PeriodicalId":9894,"journal":{"name":"Ceylon Journal of Science","volume":"20 11","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140425160","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Natural phenomena or physical systems can be described using Partial Differential Equations (PDEs), such as wave equations, heat equations, Poisson’s equation, and so on. Consequently, investigations of PDEs have become one of the key areas of modern mathematical analyses, attracting a lot of attention. Many authors have recently expressed an interest in researching the theoretical framework of fuzzy Initial Value Problems (IVPs). The Method of Directly Defining the inverse Mapping (MDDiM) was effectively employed in this research to obtain the second-order approximate fuzzy solution of heatlike equations in one and two dimensions, and the results were compared with exact solutions. In each illustrated example, all the results achieved using Maple 16 were graphically depicted. This is the first time MDDiM was utilized to solve nonlinear Fuzzy Partial Differential Equations (FPDEs).
自然现象或物理系统可以用偏微分方程（PDE）来描述，如波方程、热方程、泊松方程等。因此，对偏微分方程的研究已成为现代数学分析的重要领域之一，引起了广泛关注。最近，许多学者都表示有兴趣研究模糊初值问题（IVP）的理论框架。本研究有效地利用了直接定义反映射法（MDDiM），得到了一维和二维类热方程的二阶近似模糊解，并将结果与精确解进行了比较。在每个示例中，使用 Maple 16 得出的所有结果都以图形方式进行了描述。这是首次利用 MDDiM 解决非线性模糊偏微分方程（FPDE）。
{"title":"Method of directly defining the inverse mapping for nonlinear fuzzy heat-like partial differential equations","authors":"C. W. Sahabandu, M. Dewasurendra","doi":"10.4038/cjs.v53i1.8197","DOIUrl":"https://doi.org/10.4038/cjs.v53i1.8197","url":null,"abstract":"Natural phenomena or physical systems can be described using Partial Differential Equations (PDEs), such as wave equations, heat equations, Poisson’s equation, and so on. Consequently, investigations of PDEs have become one of the key areas of modern mathematical analyses, attracting a lot of attention. Many authors have recently expressed an interest in researching the theoretical framework of fuzzy Initial Value Problems (IVPs). The Method of Directly Defining the inverse Mapping (MDDiM) was effectively employed in this research to obtain the second-order approximate fuzzy solution of heatlike equations in one and two dimensions, and the results were compared with exact solutions. In each illustrated example, all the results achieved using Maple 16 were graphically depicted. This is the first time MDDiM was utilized to solve nonlinear Fuzzy Partial Differential Equations (FPDEs).","PeriodicalId":9894,"journal":{"name":"Ceylon Journal of Science","volume":"55 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140445435","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
H. B. P. Sandani, G. G. C. Sithumini, H. L. D. Weerahewa
Seven selected bacterial antagonists isolated from healthy tomato rhizosphere and phyllosphere were evaluated for their biocontrol efficacy against the tomato early blight causal agent Alternaria alternata under in vitro conditions. The causal organism of early blight of tomato was isolated from a tomato leaf sample which showed early blight symptoms and verified it as Alternaria alternata. Healthy tomato rhizosphere soil, fructosphere and phyllosphere extracts were used as the potential sources of antagonists. Thirty bacterial isolates from tomato rhizosphere soil and 22 bacterial isolates from tomato phyllosphere were isolated using serial dilution technique. Out of those isolates, 24 were subjected to antagonists screening procedure. It was observed that, all the bacterial isolates except RA 5, RA 21, PA 1, PA 2, inhibited the growth of A. alternata significantly (p<0.05) in co-cultivation and dual culture showing an average radial growth inhibition of 69 %. Seven different bacterial isolates coded as RA 8, RA 12, RA 17, RA 18, RA 29, PA 4 and PA 12 were selected for further studies. Based on 16 S rRNA analysis, four of these antagonists were identified as Bacillus thuringiensis, Bacillus cereus and Pseudomonas sp. Microscopic observations of A. alternata hyphae subjected to antagonism showed deviations from the normal hyphae including thickenings, swellings and vacuolation. Inhibition of A. alternata spore germination by selected antagonists was significant at p<0.05 level with an average inhibition of 83.7 %. All the selected antagonists produced diffusible antifungal substances and showed hyperparasitism and competition as their mechanisms in antagonizing the fungal pathogen A. alternata. These results suggested that these seven bacterial isolates can be further explored as potential biocontrol agents in controlling early blight disease in tomato.
在离体条件下，评估了从健康番茄根瘤层和叶球层中分离出的七种细菌拮抗剂对番茄早疫病病原菌交替丝核菌（Alternaria alternata）的生物防治效果。从出现早疫病症状的番茄叶片样本中分离出了番茄早疫病的病原菌，并确认其为交替丝核菌。健康番茄根瘤层土壤、果实层和叶球提取物被用作潜在的拮抗剂来源。采用系列稀释技术从番茄根圈土壤中分离出 30 个细菌分离物，从番茄叶球中分离出 22 个细菌分离物。在这些分离物中，有 24 个进行了拮抗剂筛选。结果表明，除 RA 5、RA 21、PA 1 和 PA 2 外，所有细菌分离物在共培养和双重培养中都能显著抑制互生菌的生长（p<0.05），平均径向生长抑制率为 69%。选取了七种不同的细菌分离物（编码分别为 RA 8、RA 12、RA 17、RA 18、RA 29、PA 4 和 PA 12）进行进一步研究。根据 16 S rRNA 分析，其中四种拮抗剂被鉴定为苏云金芽孢杆菌、蜡样芽孢杆菌和假单胞菌。选定的拮抗剂对交替孢霉孢子萌发的抑制作用明显，平均抑制率为 83.7%，P<0.05。所有被选中的拮抗剂都能产生可扩散的抗真菌物质，并显示出其拮抗真菌病原体交替孢霉的机制是超寄生和竞争。这些结果表明，这七种细菌分离物可作为潜在的生物防治剂用于控制番茄早疫病。
{"title":"Biocontrol potential of some selected native bacterial antagonists against tomato (Solanum lycopersicum L.) early blight causal agent Alternaria alternata","authors":"H. B. P. Sandani, G. G. C. Sithumini, H. L. D. Weerahewa","doi":"10.4038/cjs.v53i1.8167","DOIUrl":"https://doi.org/10.4038/cjs.v53i1.8167","url":null,"abstract":"Seven selected bacterial antagonists isolated from healthy tomato rhizosphere and phyllosphere were evaluated for their biocontrol efficacy against the tomato early blight causal agent Alternaria alternata under in vitro conditions. The causal organism of early blight of tomato was isolated from a tomato leaf sample which showed early blight symptoms and verified it as Alternaria alternata. Healthy tomato rhizosphere soil, fructosphere and phyllosphere extracts were used as the potential sources of antagonists. Thirty bacterial isolates from tomato rhizosphere soil and 22 bacterial isolates from tomato phyllosphere were isolated using serial dilution technique. Out of those isolates, 24 were subjected to antagonists screening procedure. It was observed that, all the bacterial isolates except RA 5, RA 21, PA 1, PA 2, inhibited the growth of A. alternata significantly (p<0.05) in co-cultivation and dual culture showing an average radial growth inhibition of 69 %. Seven different bacterial isolates coded as RA 8, RA 12, RA 17, RA 18, RA 29, PA 4 and PA 12 were selected for further studies. Based on 16 S rRNA analysis, four of these antagonists were identified as Bacillus thuringiensis, Bacillus cereus and Pseudomonas sp. Microscopic observations of A. alternata hyphae subjected to antagonism showed deviations from the normal hyphae including thickenings, swellings and vacuolation. Inhibition of A. alternata spore germination by selected antagonists was significant at p<0.05 level with an average inhibition of 83.7 %. All the selected antagonists produced diffusible antifungal substances and showed hyperparasitism and competition as their mechanisms in antagonizing the fungal pathogen A. alternata. These results suggested that these seven bacterial isolates can be further explored as potential biocontrol agents in controlling early blight disease in tomato.","PeriodicalId":9894,"journal":{"name":"Ceylon Journal of Science","volume":"22 19","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139778575","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
H. B. P. Sandani, G. G. C. Sithumini, H. L. D. Weerahewa
Seven selected bacterial antagonists isolated from healthy tomato rhizosphere and phyllosphere were evaluated for their biocontrol efficacy against the tomato early blight causal agent Alternaria alternata under in vitro conditions. The causal organism of early blight of tomato was isolated from a tomato leaf sample which showed early blight symptoms and verified it as Alternaria alternata. Healthy tomato rhizosphere soil, fructosphere and phyllosphere extracts were used as the potential sources of antagonists. Thirty bacterial isolates from tomato rhizosphere soil and 22 bacterial isolates from tomato phyllosphere were isolated using serial dilution technique. Out of those isolates, 24 were subjected to antagonists screening procedure. It was observed that, all the bacterial isolates except RA 5, RA 21, PA 1, PA 2, inhibited the growth of A. alternata significantly (p<0.05) in co-cultivation and dual culture showing an average radial growth inhibition of 69 %. Seven different bacterial isolates coded as RA 8, RA 12, RA 17, RA 18, RA 29, PA 4 and PA 12 were selected for further studies. Based on 16 S rRNA analysis, four of these antagonists were identified as Bacillus thuringiensis, Bacillus cereus and Pseudomonas sp. Microscopic observations of A. alternata hyphae subjected to antagonism showed deviations from the normal hyphae including thickenings, swellings and vacuolation. Inhibition of A. alternata spore germination by selected antagonists was significant at p<0.05 level with an average inhibition of 83.7 %. All the selected antagonists produced diffusible antifungal substances and showed hyperparasitism and competition as their mechanisms in antagonizing the fungal pathogen A. alternata. These results suggested that these seven bacterial isolates can be further explored as potential biocontrol agents in controlling early blight disease in tomato.
在离体条件下，评估了从健康番茄根瘤层和叶球层中分离出的七种细菌拮抗剂对番茄早疫病病原菌交替丝核菌（Alternaria alternata）的生物防治效果。从出现早疫病症状的番茄叶片样本中分离出了番茄早疫病的病原菌，并确认其为交替丝核菌。健康番茄根瘤层土壤、果实层和叶球提取物被用作潜在的拮抗剂来源。采用系列稀释技术从番茄根圈土壤中分离出 30 个细菌分离物，从番茄叶球中分离出 22 个细菌分离物。在这些分离物中，有 24 个进行了拮抗剂筛选。结果表明，除 RA 5、RA 21、PA 1 和 PA 2 外，所有细菌分离物在共培养和双重培养中都能显著抑制互生菌的生长（p<0.05），平均径向生长抑制率为 69%。选取了七种不同的细菌分离物（编码分别为 RA 8、RA 12、RA 17、RA 18、RA 29、PA 4 和 PA 12）进行进一步研究。根据 16 S rRNA 分析，其中四种拮抗剂被鉴定为苏云金芽孢杆菌、蜡样芽孢杆菌和假单胞菌。选定的拮抗剂对交替孢霉孢子萌发的抑制作用明显，平均抑制率为 83.7%，P<0.05。所有被选中的拮抗剂都能产生可扩散的抗真菌物质，并显示出其拮抗真菌病原体交替孢霉的机制是超寄生和竞争。这些结果表明，这七种细菌分离物可作为潜在的生物防治剂用于控制番茄早疫病。
{"title":"Biocontrol potential of some selected native bacterial antagonists against tomato (Solanum lycopersicum L.) early blight causal agent Alternaria alternata","authors":"H. B. P. Sandani, G. G. C. Sithumini, H. L. D. Weerahewa","doi":"10.4038/cjs.v53i1.8167","DOIUrl":"https://doi.org/10.4038/cjs.v53i1.8167","url":null,"abstract":"Seven selected bacterial antagonists isolated from healthy tomato rhizosphere and phyllosphere were evaluated for their biocontrol efficacy against the tomato early blight causal agent Alternaria alternata under in vitro conditions. The causal organism of early blight of tomato was isolated from a tomato leaf sample which showed early blight symptoms and verified it as Alternaria alternata. Healthy tomato rhizosphere soil, fructosphere and phyllosphere extracts were used as the potential sources of antagonists. Thirty bacterial isolates from tomato rhizosphere soil and 22 bacterial isolates from tomato phyllosphere were isolated using serial dilution technique. Out of those isolates, 24 were subjected to antagonists screening procedure. It was observed that, all the bacterial isolates except RA 5, RA 21, PA 1, PA 2, inhibited the growth of A. alternata significantly (p<0.05) in co-cultivation and dual culture showing an average radial growth inhibition of 69 %. Seven different bacterial isolates coded as RA 8, RA 12, RA 17, RA 18, RA 29, PA 4 and PA 12 were selected for further studies. Based on 16 S rRNA analysis, four of these antagonists were identified as Bacillus thuringiensis, Bacillus cereus and Pseudomonas sp. Microscopic observations of A. alternata hyphae subjected to antagonism showed deviations from the normal hyphae including thickenings, swellings and vacuolation. Inhibition of A. alternata spore germination by selected antagonists was significant at p<0.05 level with an average inhibition of 83.7 %. All the selected antagonists produced diffusible antifungal substances and showed hyperparasitism and competition as their mechanisms in antagonizing the fungal pathogen A. alternata. These results suggested that these seven bacterial isolates can be further explored as potential biocontrol agents in controlling early blight disease in tomato.","PeriodicalId":9894,"journal":{"name":"Ceylon Journal of Science","volume":"44 7","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139838302","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. A. K. L. Dissanayakea, T. S. M. Liyanage, J. Kumari, D. M. U. P. Sumanasekera, T. Jaseetharan, W. I. Sandamali, G. Senadeera
A low-cost, activated carbon (AC) and sugar-coated stainless-steel counter electrode for dye-sensitized solar cells was successfully fabricated and characterized. For performance comparison, a similar electrode was fabricated using a FTO glass as the substrate. The photovoltaic performance of dye-sensitized solar cells made with these two counter electrodes were compared with solar cells made with a Pt counter electrode. The optimized, activated carbon-coated, stainless-steel-based dye-sensitized solar cells showed an energy conversion efficiency of 8.21% while similarly optimized solar cells made with activated carboncoated FTO counter electrode showed an efficiency of 7.50%. The efficiency of corresponding solar cells made with Pt counter electrode was 9.22%. The high solar cell efficiency of 89% of that of Pt based cells can be attributed to the high electro-catalytic activity and enhanced effective surface area of activated carbon/ sugar composite and good electrical conductivity of stainless steel as demonstrated by electrochemical impedance spectroscopy, cyclic voltammetry, Tafel plot analysis and SEM imaging.
{"title":"A low-cost, activated carbon-coated, stainless-steel counter electrode for dye-sensitized solar cells","authors":"M. A. K. L. Dissanayakea, T. S. M. Liyanage, J. Kumari, D. M. U. P. Sumanasekera, T. Jaseetharan, W. I. Sandamali, G. Senadeera","doi":"10.4038/cjs.v53i1.8237","DOIUrl":"https://doi.org/10.4038/cjs.v53i1.8237","url":null,"abstract":"A low-cost, activated carbon (AC) and sugar-coated stainless-steel counter electrode for dye-sensitized solar cells was successfully fabricated and characterized. For performance comparison, a similar electrode was fabricated using a FTO glass as the substrate. The photovoltaic performance of dye-sensitized solar cells made with these two counter electrodes were compared with solar cells made with a Pt counter electrode. The optimized, activated carbon-coated, stainless-steel-based dye-sensitized solar cells showed an energy conversion efficiency of 8.21% while similarly optimized solar cells made with activated carboncoated FTO counter electrode showed an efficiency of 7.50%. The efficiency of corresponding solar cells made with Pt counter electrode was 9.22%. The high solar cell efficiency of 89% of that of Pt based cells can be attributed to the high electro-catalytic activity and enhanced effective surface area of activated carbon/ sugar composite and good electrical conductivity of stainless steel as demonstrated by electrochemical impedance spectroscopy, cyclic voltammetry, Tafel plot analysis and SEM imaging.","PeriodicalId":9894,"journal":{"name":"Ceylon Journal of Science","volume":"126 8","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139780978","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. A. K. L. Dissanayakea, T. S. M. Liyanage, J. Kumari, D. M. U. P. Sumanasekera, T. Jaseetharan, W. I. Sandamali, G. Senadeera
A low-cost, activated carbon (AC) and sugar-coated stainless-steel counter electrode for dye-sensitized solar cells was successfully fabricated and characterized. For performance comparison, a similar electrode was fabricated using a FTO glass as the substrate. The photovoltaic performance of dye-sensitized solar cells made with these two counter electrodes were compared with solar cells made with a Pt counter electrode. The optimized, activated carbon-coated, stainless-steel-based dye-sensitized solar cells showed an energy conversion efficiency of 8.21% while similarly optimized solar cells made with activated carboncoated FTO counter electrode showed an efficiency of 7.50%. The efficiency of corresponding solar cells made with Pt counter electrode was 9.22%. The high solar cell efficiency of 89% of that of Pt based cells can be attributed to the high electro-catalytic activity and enhanced effective surface area of activated carbon/ sugar composite and good electrical conductivity of stainless steel as demonstrated by electrochemical impedance spectroscopy, cyclic voltammetry, Tafel plot analysis and SEM imaging.
{"title":"A low-cost, activated carbon-coated, stainless-steel counter electrode for dye-sensitized solar cells","authors":"M. A. K. L. Dissanayakea, T. S. M. Liyanage, J. Kumari, D. M. U. P. Sumanasekera, T. Jaseetharan, W. I. Sandamali, G. Senadeera","doi":"10.4038/cjs.v53i1.8237","DOIUrl":"https://doi.org/10.4038/cjs.v53i1.8237","url":null,"abstract":"A low-cost, activated carbon (AC) and sugar-coated stainless-steel counter electrode for dye-sensitized solar cells was successfully fabricated and characterized. For performance comparison, a similar electrode was fabricated using a FTO glass as the substrate. The photovoltaic performance of dye-sensitized solar cells made with these two counter electrodes were compared with solar cells made with a Pt counter electrode. The optimized, activated carbon-coated, stainless-steel-based dye-sensitized solar cells showed an energy conversion efficiency of 8.21% while similarly optimized solar cells made with activated carboncoated FTO counter electrode showed an efficiency of 7.50%. The efficiency of corresponding solar cells made with Pt counter electrode was 9.22%. The high solar cell efficiency of 89% of that of Pt based cells can be attributed to the high electro-catalytic activity and enhanced effective surface area of activated carbon/ sugar composite and good electrical conductivity of stainless steel as demonstrated by electrochemical impedance spectroscopy, cyclic voltammetry, Tafel plot analysis and SEM imaging.","PeriodicalId":9894,"journal":{"name":"Ceylon Journal of Science","volume":"112 11","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139840698","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Weerasooriya, D. Dissanayake, M. Ariyaratne, U. Rathnayake, H. Kadupitiya, R. Chandrajith, L. Suriyagoda
Cobalt (Co) is considered a beneficial element for plants. However, when soils contain excessive amounts of Co, it could cause phytotoxicity. Despite this, the current status of Co in Sri Lankan rice-cultivated soils is not known. Therefore, this study was conducted to (i) determine the distribution of exchangeable Co concentration, and (ii) examine the interactive effects of climatic zone (CZ), agro-climatic zone (ACZ), soil order, water source, and their interactions in determining exchangeable Co concentration in lowland rice fields in Sri Lanka. A total of 8,292 soil samples representing six ACZs, six soil orders, and three water sources were collected using a stratified random sampling approach. Cobalt was extracted in 0.01 M CaCl2 and measured using Inductively Coupled Plasma Mass Spectrophotometry. Exchangeable Co concentration ranged between 0.03-2,409 μg kg−1 with a mean value of 185.9 μg kg−1. Over 77.5% of the soil samples tested were Co deficient, i.e. <250 μg kg−1. Samples collected from the Intermediate zone, particularly Intermediate zone Mid country, had higher Co concentration than that reported in other ACZs (p<0.05). Among the soil orders, Histosols had higher (232 μg kg−1) and Vertisols had lower (91 μg kg−1) Co concentrations (p<0.05). Moreover, Co concentration was negatively correlated with soil pH (r=−0.3391, p<0.0001) and rice crop productivity (r=−0.1512, p<0.0001). Although exchangeable Co concentration in rice cultivated soils was low, it is important to implement strategies such as proper waste management, treatment of industrial effluents, and the use of safer and more sustainable practices in the chemical and mining industries to minimize further accumulation of Co exceeding the critical limit (i.e. 30 - 40 mg Co kg−1 rice grain), and to ensure the safety of rice production in situations where geological and anthropogenic activities can increase soil exchangeable Co concentration.
{"title":"Distribution of exchangeable cobalt in low-land rice cultivated soils in Sri Lanka as affected by the differences in climate, soil and water source","authors":"T. Weerasooriya, D. Dissanayake, M. Ariyaratne, U. Rathnayake, H. Kadupitiya, R. Chandrajith, L. Suriyagoda","doi":"10.4038/cjs.v53i1.8344","DOIUrl":"https://doi.org/10.4038/cjs.v53i1.8344","url":null,"abstract":"Cobalt (Co) is considered a beneficial element for plants. However, when soils contain excessive amounts of Co, it could cause phytotoxicity. Despite this, the current status of Co in Sri Lankan rice-cultivated soils is not known. Therefore, this study was conducted to (i) determine the distribution of exchangeable Co concentration, and (ii) examine the interactive effects of climatic zone (CZ), agro-climatic zone (ACZ), soil order, water source, and their interactions in determining exchangeable Co concentration in lowland rice fields in Sri Lanka. A total of 8,292 soil samples representing six ACZs, six soil orders, and three water sources were collected using a stratified random sampling approach. Cobalt was extracted in 0.01 M CaCl2 and measured using Inductively Coupled Plasma Mass Spectrophotometry. Exchangeable Co concentration ranged between 0.03-2,409 μg kg−1 with a mean value of 185.9 μg kg−1. Over 77.5% of the soil samples tested were Co deficient, i.e. <250 μg kg−1. Samples collected from the Intermediate zone, particularly Intermediate zone Mid country, had higher Co concentration than that reported in other ACZs (p<0.05). Among the soil orders, Histosols had higher (232 μg kg−1) and Vertisols had lower (91 μg kg−1) Co concentrations (p<0.05). Moreover, Co concentration was negatively correlated with soil pH (r=−0.3391, p<0.0001) and rice crop productivity (r=−0.1512, p<0.0001). Although exchangeable Co concentration in rice cultivated soils was low, it is important to implement strategies such as proper waste management, treatment of industrial effluents, and the use of safer and more sustainable practices in the chemical and mining industries to minimize further accumulation of Co exceeding the critical limit (i.e. 30 - 40 mg Co kg−1 rice grain), and to ensure the safety of rice production in situations where geological and anthropogenic activities can increase soil exchangeable Co concentration.","PeriodicalId":9894,"journal":{"name":"Ceylon Journal of Science","volume":"175 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139840634","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Weerasooriya, D. Dissanayake, M. Ariyaratne, U. Rathnayake, H. Kadupitiya, R. Chandrajith, L. Suriyagoda
Cobalt (Co) is considered a beneficial element for plants. However, when soils contain excessive amounts of Co, it could cause phytotoxicity. Despite this, the current status of Co in Sri Lankan rice-cultivated soils is not known. Therefore, this study was conducted to (i) determine the distribution of exchangeable Co concentration, and (ii) examine the interactive effects of climatic zone (CZ), agro-climatic zone (ACZ), soil order, water source, and their interactions in determining exchangeable Co concentration in lowland rice fields in Sri Lanka. A total of 8,292 soil samples representing six ACZs, six soil orders, and three water sources were collected using a stratified random sampling approach. Cobalt was extracted in 0.01 M CaCl2 and measured using Inductively Coupled Plasma Mass Spectrophotometry. Exchangeable Co concentration ranged between 0.03-2,409 μg kg−1 with a mean value of 185.9 μg kg−1. Over 77.5% of the soil samples tested were Co deficient, i.e. <250 μg kg−1. Samples collected from the Intermediate zone, particularly Intermediate zone Mid country, had higher Co concentration than that reported in other ACZs (p<0.05). Among the soil orders, Histosols had higher (232 μg kg−1) and Vertisols had lower (91 μg kg−1) Co concentrations (p<0.05). Moreover, Co concentration was negatively correlated with soil pH (r=−0.3391, p<0.0001) and rice crop productivity (r=−0.1512, p<0.0001). Although exchangeable Co concentration in rice cultivated soils was low, it is important to implement strategies such as proper waste management, treatment of industrial effluents, and the use of safer and more sustainable practices in the chemical and mining industries to minimize further accumulation of Co exceeding the critical limit (i.e. 30 - 40 mg Co kg−1 rice grain), and to ensure the safety of rice production in situations where geological and anthropogenic activities can increase soil exchangeable Co concentration.
{"title":"Distribution of exchangeable cobalt in low-land rice cultivated soils in Sri Lanka as affected by the differences in climate, soil and water source","authors":"T. Weerasooriya, D. Dissanayake, M. Ariyaratne, U. Rathnayake, H. Kadupitiya, R. Chandrajith, L. Suriyagoda","doi":"10.4038/cjs.v53i1.8344","DOIUrl":"https://doi.org/10.4038/cjs.v53i1.8344","url":null,"abstract":"Cobalt (Co) is considered a beneficial element for plants. However, when soils contain excessive amounts of Co, it could cause phytotoxicity. Despite this, the current status of Co in Sri Lankan rice-cultivated soils is not known. Therefore, this study was conducted to (i) determine the distribution of exchangeable Co concentration, and (ii) examine the interactive effects of climatic zone (CZ), agro-climatic zone (ACZ), soil order, water source, and their interactions in determining exchangeable Co concentration in lowland rice fields in Sri Lanka. A total of 8,292 soil samples representing six ACZs, six soil orders, and three water sources were collected using a stratified random sampling approach. Cobalt was extracted in 0.01 M CaCl2 and measured using Inductively Coupled Plasma Mass Spectrophotometry. Exchangeable Co concentration ranged between 0.03-2,409 μg kg−1 with a mean value of 185.9 μg kg−1. Over 77.5% of the soil samples tested were Co deficient, i.e. <250 μg kg−1. Samples collected from the Intermediate zone, particularly Intermediate zone Mid country, had higher Co concentration than that reported in other ACZs (p<0.05). Among the soil orders, Histosols had higher (232 μg kg−1) and Vertisols had lower (91 μg kg−1) Co concentrations (p<0.05). Moreover, Co concentration was negatively correlated with soil pH (r=−0.3391, p<0.0001) and rice crop productivity (r=−0.1512, p<0.0001). Although exchangeable Co concentration in rice cultivated soils was low, it is important to implement strategies such as proper waste management, treatment of industrial effluents, and the use of safer and more sustainable practices in the chemical and mining industries to minimize further accumulation of Co exceeding the critical limit (i.e. 30 - 40 mg Co kg−1 rice grain), and to ensure the safety of rice production in situations where geological and anthropogenic activities can increase soil exchangeable Co concentration.","PeriodicalId":9894,"journal":{"name":"Ceylon Journal of Science","volume":"129 16","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139780921","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
H. G. A. S. Samarasinghe, K. Gunathilake, D. C. K. Illeperuma
Morinda citrifolia (L.), also known as Noni or Ahu in Sri Lanka, is infrequently consumed as a dietary supplement within the country due to its association with myths and perceived toxicity. Nonetheless, in Sri Lanka, limited scientific research has been undertaken in the past to explore the therapeutic potential of noni, with public awareness primarily focused on its exportdriven cultivation. The study focused on evaluating the proximate composition, bioactive constituents, and therapeutic potential of hydro-methanolic extracts from pasteurized noni fruit juice, employing an 80% methanol extraction method, filtration, and assessment through standard assays to elucidate its potentia health benefits. The juice showed noteworthy antioxidant potential through DPPH scavenging activity (57.90 ± 0.40 μg/mL) and ABTS scavenging activity (42.95 ± 1.33 μg/mL), as well as high nitric oxide inhibition activity (164.56 ± 3.22 μg/mL), suggesting its anti-inflammatory properties. The juice also displayed potential as an anti-diabetic agent by inhibiting alpha-amylase (27.68 ± 0.36 μg/mL) and alpha-glucosidase (25.67 ± 1.03 μg/mL). Furthermore, it exhibited potential in protecting against certain pathological processes through heat-induced hemolysis inhibition (36.08 ± 1.08 μg/mL), protein denaturation inhibition (56.14 ± 1.11 μg/mL), and proteinase inhibitory activity (38.04 ± 0.56 μg/mL). These findings support the potential use of pasteurized fruit juice as a functional food ingredient, offering benefits to both the food industry and consumers. Further research can be directed towards the development of Noni fruit-incorporated food products that possess desirable sensory attributes to mitigate any potential aversion associated with its taste and odor profiles.
{"title":"Proximate composition, bioactive constituents, and therapeutic potentials of pasteurized Noni juice derived from Morinda citrifolia (L.) growing in Sri Lanka","authors":"H. G. A. S. Samarasinghe, K. Gunathilake, D. C. K. Illeperuma","doi":"10.4038/cjs.v53i1.8141","DOIUrl":"https://doi.org/10.4038/cjs.v53i1.8141","url":null,"abstract":"Morinda citrifolia (L.), also known as Noni or Ahu in Sri Lanka, is infrequently consumed as a dietary supplement within the country due to its association with myths and perceived toxicity. Nonetheless, in Sri Lanka, limited scientific research has been undertaken in the past to explore the therapeutic potential of noni, with public awareness primarily focused on its exportdriven cultivation. The study focused on evaluating the proximate composition, bioactive constituents, and therapeutic potential of hydro-methanolic extracts from pasteurized noni fruit juice, employing an 80% methanol extraction method, filtration, and assessment through standard assays to elucidate its potentia health benefits. The juice showed noteworthy antioxidant potential through DPPH scavenging activity (57.90 ± 0.40 μg/mL) and ABTS scavenging activity (42.95 ± 1.33 μg/mL), as well as high nitric oxide inhibition activity (164.56 ± 3.22 μg/mL), suggesting its anti-inflammatory properties. The juice also displayed potential as an anti-diabetic agent by inhibiting alpha-amylase (27.68 ± 0.36 μg/mL) and alpha-glucosidase (25.67 ± 1.03 μg/mL). Furthermore, it exhibited potential in protecting against certain pathological processes through heat-induced hemolysis inhibition (36.08 ± 1.08 μg/mL), protein denaturation inhibition (56.14 ± 1.11 μg/mL), and proteinase inhibitory activity (38.04 ± 0.56 μg/mL). These findings support the potential use of pasteurized fruit juice as a functional food ingredient, offering benefits to both the food industry and consumers. Further research can be directed towards the development of Noni fruit-incorporated food products that possess desirable sensory attributes to mitigate any potential aversion associated with its taste and odor profiles.","PeriodicalId":9894,"journal":{"name":"Ceylon Journal of Science","volume":"77 14","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139784740","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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