University of Sri Jayewardenepura: Journals & Proceedings
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Bio-efficacy and Persistence of Inert Dust Formulations as Stored-grain Protectants against Sitophilus oryzae (L.)
Get PDFInert dust formulations of natural origin act as promising alternatives in controlling storage infestations caused by deleterious coleopteran insect pests. In that context, laboratory studies were conducted in order to evaluate the insecticidal activity, progeny inhibition and persistence of three commercially available dust formulations, namely, diatomaceous earth, zeolite and cloisite 20A against Sitophilus oryzae adults, a major coleopteran pest of stored grains, throughout 90 days of storage period. Adulticidal and persistence bioassays were conducted to evaluate the toxicity of binary combinations of inert dusts using their sub-lethal doses towards the test insect for 60 days of storage period. Further, ultrastructural architecture of the test insect pest species was examined via Field Emission Scanning Electron Microscopy (FE-SEM), and Energy Dispersive X-Ray Analysis (EDX) to study the uptake/penetration pattern of inert dust particles through the cuticular layers of target insect pest. All inert dust formulations exhibited very efficacious toxic and progeny inhibition activities and extraordinary mortality percentages irrespective of the inert dust used at the end of initial 30 day-long storage period. Thereafter, mortality percentages gradually declined with the progress of the storage time period, declining in the order of, diatomaceous earth>zeolite>cloisite 20A. All the dust formulations successfully inhibited the progeny production and the lowest average progeny production was recorded at the end of initial storage period. Progeny inhibition decreased with the progress of storage time. Binary combinations of inert dust formulations exhibited additive and antagonistic effects against S. oryzae and similarly, the mortality percentages gradually decreased with the prolongation of the storage period. The FE-SEM and EDX micrographs clearly indicated the presence of dust particles and the distribution of their constituting elements on the cuticular layer of the exposed insect pests with the appearances of abrasions and scratches that may have led to dehydration and eventual death of S. oryzae. Thus, findings of the present study suggest that, naturally-derived diatomaceous earth, zeolite and cloisite 20A can be used as eco-friendly means as stored grain protectants against S. oryzae populations successfully in the storage grain systems.
Keywords: Sitophilus oryzae, Diatomaceous earth, Cloisite 20A, Zeolit
On-water Catalyst-free Synthesis of 3-Alkenyl Oxindoles
Get PDF3-Alkenyl oxindoles are key structural motifs in organic chemistry with a wide range of applications mainly in the pharmaceutical industry, due to excellent biological activities such as anti-inflammatory, antiviral, antibacterial, and anticancer properties. With the discovery of the importance of oxindole derivatives in the pharmaceutical industry, demand for sustainable protocols for the synthesis increased as most classical methods have their limitations and flaws. In this study on-water, catalyst-free, atom-economical green approach was developed for the synthesis of 3- alkenyl oxindole derivatives using oxindole and aldehyde as starting materials. The reaction between oxindole and benzaldehyde was conducted on water under catalyst-free conditions. Interestingly, 100% conversion was observed when the reaction was carried out for 24 hours at 100° C. As the next step, the applicability of the developed approach was proven for different aldehydes. Furaldehyde, cinnamaldehyde, and vanillin were used as the aldehydes to synthesize 3- alkenyl oxindole derivatives, and the isolated yields were obtained as 77%, 54%, and 51% respectively. The desired product formation was confirmed by comparing the Rf value of the product with that of the previously synthesized well-characterized compounds; 3- benzylideneindolin-2-one, 3-(furan-3-methylene)indolin-2-one, 3-(3-phenylallylidene)indolin-2- one, and 3-(4-hydroxy-3-methoxybenzylidene)indolin-2-one using Thin Layer Chromatography. Further characterization was done by Fourier-transform infrared (FT-IR), Ultraviolet-visible (UVVis), and Nuclear Magnetic Resonance (NMR) spectroscopic techniques. In further optimization steps, the reaction was performed using surfactants as the catalyst. By adhering to the green chemistry principles different sources of biosurfactants were used including Acacia concinna pods, Sapindus emarginatus fruit pericarp, Dillenia retusa fruit pericarp, and Trigonella foenumgraecum seeds. In order to compare the effect of biosurfactants, a synthetic surfactant, sodium dodecyl sulfate (SDS) was used as the catalyst. When the reaction was carried out for 21 hours at 100 °C using fruit pericarp of Sapindus emarginatus as the source of biosurfactant, 100% conversion was observed. Using water as the solvent, readily available starting materials, higher yield, and eco-friendliness and catalyst-free conditions suggest the possible use of the developed method for large-scale preparations of 3-alkenyl oxindole derivatives.
Keywords: Green protocol, Oxindole derivatives, Surfactant, On water synthesis, Catalyst-fre
Characterization of Thermostable Cellulase Enzyme Isolated from a Hot Spring Bacterium: Bacillus sp.
Get PDFCellulase is a complex of enzymes which consists of β-1,4-endoglucanase, cellobiohydrolase, and β-glucosidase. Cellulase contributes a significant share to the world enzyme market and is used in number of industries viz; paper and pulp, food and beverage, bioethanol, detergent and textile. The harsh industrial conditions such as high temperature, extreme pH levels and high substrate concentration etc. which is used in such industries adversely effect on structure and activity of enzymes. Therefore, huge amount of chemical catalysts which cause chemical wastes are used in industrial settings instead of enzymes. Since the chemical wastes adversely affect the ecosystem, isolation and characterization of thermostable cellulase enzyme-producing bacteria and exploring the industrial perspective of thermostable enzymes is a better approach towards green chemistry. The present study focused on characterization of cellulase enzyme produced by Bacillus sp., which shows optimum activity at 60 C under neutral conditions, isolated from Gomarankadavala hot spring in Sri Lanka. The effect of different Carbon sources: glucose and lactose, Nitrogen sources: peptone, tryptone, yeast extract and urea on enzyme production and different Carboxymethylcellulose (CMC) concentrations; 0.5%, 1.5% and 2%, on enzyme activity were measured using the DNS method. Under the optimum conditions, cellulase enzyme activity on different substrates: corn cob, rice bran and raw leaves were measured. The highest enzyme production was recorded in the culture medium which added tryptone as the nitrogen source and adding carbon sources to the culture medium showed an increase of cellulase enzyme production. The optimum CMC concentration for the enzyme activity was recorded as 1% and from all the optimized parameters, the substrate; raw leaves showed the highest enzyme activity of 11.305 U/ml. Further, a considerable amount of enzyme activity was recorded on corn cobs and rice bran as well. Thus, the thermostable cellulase enzyme produced by bacterium identified as Bacillus cereus isolated from Gomarankadavala hot spring could be successfully used in industrial settings such as kitchen/industrial waste management, bioethanol production, paper and pulp industry and textile industry which use high temperatures and cellulosic substrates as raw materials.
Keywords: Thermostable enzymes, Cellulase, Industrial applications, Hot springs 
A Quality Review of EIA: A Comparative Study of State-Funded and International Aid Agency-funded Development Projects in Sri Lanka
Get PDFA development project's environmental impact assessment (EIA) is a tool for mitigating the effects on the environment and promoting sustainable development. EIA is an expensive and professionally engaged process that involves the public. Many countries around the world have long-standing laws in place connected to this topic, as well as solid knowledge and experience. One persistent argument against the efficacy of EIA in developing nations is that the procedure and quality differ from country to country. The International Aid Agencies (IAA) have their guidelines for protecting the environment while following local environmental assessment standards for any financing requirements. IAA involvement in the EIA process might significantly affect how well- written EIA reports are. To evaluate the assessment quality, six EIA reports from state-financed development projects (SL-EIAs) and another six development projects EIAs funded by the IAA (IAA-EIAs) in Sri Lanka were randomly chosen. LeeCooley review package (1990) was used to evaluate the Environmental Impact Statements (EIS) of each EIA. In this investigation, it was discovered that IAA-EIAs and SL-EIAs had a significant difference in overall quality. IAA-EIAs show values that range from highly satisfactory to satisfactory and each share 50 percent, whereas SL-EIAs indicate 83 percent satisfactory and 17 percent of borderline quality. In comparison to the SL-EIAs, all four review areas of the IAA-EIAs performed notably well. While the SL-EIA shows good to borderline quality (0.66-0.72), all evaluated IAA-EIA reports reveal highly satisfactory to satisfactory (0.81-0.93) quality. The engagement of IAA in the environmental assessment has a considerable impact to improve assessment quality in comparison to the only domestic assessment. Finding the weak area in the SL-EIA process and adhering to the IAA standards would elevate the standard of the report.
Keywords: EIA quality, Review, International Aid Agency, Development project
Application of Participatory Concept in Minimizing Food Packaging Waste (FPW) in Manufacturing Firms
Get PDFAll the industrialized countries lately focus on the need for the best solutions for the reduction of food waste at the various stages of the supply chain by conducting the participatory concept. It is a solution and stakeholder-oriented concept providing information on how to analyze the status quo identification of organization-specific problems and with the involvement of relevant stakeholders, develop solutions in the processes along the food value chain. The objective of this study is to present a participatory (five-phase) concept to diminish FPW in manufacturing firms. This concept is adapted to the continuous improvement (PDCA cycle) applied in Total Quality Management (TQM), which involves a participatory approach where workers and stakeholders are collaborated to detect causes for inefficiency and advance measures to counteract FPW in the Healthy Food Drink powder Manufacturing firm. The research was conducted by analyzing the data related to FPW such as Aluminum Wrappers (AlWs), Bag in Boxes (BIBs), and Plastic Bottles (PBs) using Microsoft Excel and Power BI software. Also, it paid attention to related operational and supporting processes within the organization and the behavior of the staff to get an impression of the working atmosphere and attitudes of staff. The analysis was done as a comparison with the collected FPW data for 2 months before and after developing, and implementing upgraded, targeted management practices. This analysis provided the basis for the developmental framework with the focus of increasing the effectiveness of FPW management practices by assessing the structure and selecting the best waste management methodologies for FPW. According to the analyzed data, the total wastage of AlWs, BIBs, and PBs showed 5.81%, 1.82% and 1.96% respectively. With the participatory concept, the organizational weaknesses which caused the occurrence of FPW were identified, and developmental measures were implemented to obtain significant reductions of waste of Alws, BIBs, and PBs up to 2.06%, 0% and 0.43% consequently. Counteractive measures, such as join in workforces into the developing and implementing waste reduction measures, workforce training, scheduled preventive maintenance on machines, utilization of removable ink-to-print date codes, efficient demand planning and accurate demand forecasting, enhance workforce motivation and commitment, establishing trust among all employees and proper communication flows within departments which influencing the occurrence of FPW have been proposed to avoid losses. It affirms that the participatory concept either contributes to reducing FPW or enhancing resource efficiency in the food industry, as this would enable companies to benefit economically.
Keywords: Food packaging waste, Participatory concept, Continuous improvement, Integration, Resource efficiency 
Pollen Morphological Studies on Selected Species of Family Dilleniaceae in Sri Lanka
Get PDFDilleniaceae is an angiosperm family including 11 genera and about 500 known species with a pantropical distribution extending into Australia. In Sri Lanka, four genera and 16 species including one introduced species have been reported in the family Dilleniaceae. Most of these species are endemic or native, while Schumacheria is an endemic genus. Morphological characters of the pollen grains are a significant taxonomic identification tool in the systematics of higher plants. The aim of the study is to provide detailed palynological descriptions of selected pollen species and maintain pollen reference collection. Four plant species, Dillenia retusa, Dillenia suffruticosa, Dillenia triquetra, and Schumacheria castaneifolia of the family Dilleniaceae (Genus Dillenia and Schumacheria) were collected from different localities in the wet zone including Nugegoda and Baduraliya during the period from September 2022 to November 2022. The voucher specimens were authenticated using revised handbook to the flora of Ceylon and deposited in the Herbarium of the Department of Botany, University of Sri Jayewardenepura, Sri Lanka. Fresh flowers or dried flowers were taken to collect pollen. Pollen grains were acetolysed and observed under Optika microscope (BG-Italy) after mounting on a clean glass slide using glycerin jelly with Basic fuchsin. Thirty pollen grains were used to determine the pollen size for each selected species. All measurements were taken within seven days of pollen preparation using OptikalSview (3.9.0.604) software. The shape, size, and surface features of pollen grains, as well as the length and width of the pollen and apertures and Polar/Equatorial ratios, were observed. Descriptive statistical analysis was performed using Minitab 18 software for the quantitative variables related to measurements of pollen obtained with light microscope. The ranges of variation were 15-22 μm for polar axis, 16-26 μm for equatorial axis, 0.8-3.5 μm for colpus width and 5.0-12.5 μm for colpus length. The pollen grains of all the species are monad, isopolar, and radially symmetrical. Pollen grains were identified as suboblate to oblate spheroidal, small or medium-sized, tricolpate (Dillenia spp.) or tetra-colpate (Schumacheria castaneifolia), with the surface ornamentation punctate to reticulate. The longest and widest pollen grains were reported in Dillenia suffruticosa (22.0×26.4 μm), while the smallest were observed in Schumacheria castaneifolia (15.2×16.4 μm). Based on the length of the longest spore axis, except D. suffruticosa all other species are categorized into small-size pollen. According to the results, the distinction between species can be determined using palynological features such as shape, size, and aperture type.
Keywords: Pollen morphology, Dilleniaceae, Palynology, Reference collection 
The Living Conditions of Boarding Houses around the University of Sri Jayewardenepura
Get PDFThe research aims to assess the living conditions of boarding houses around the University of Sri Jayewardenepura. Internal dimensions, light, ventilation and room space were used to measure living conditions in boarding houses. The study employed a mixed-method approach to gather data. Descriptive and content analysis methods were used to analyse the data collected using a purposive sample of 70 boarding houses and interviews with 10 owners. The findings of the study revealed mixed results regarding the living conditions of boarding houses. Overcrowding is a major issue that led to most of the boarding houses failing to meet the minimum space requirements for tenants, leading to compromised living conditions. The study provides insights that can help policymakers to enhance regulations and standards to improve the well-being of the tenants
Construction Industry and Human Resource Management: A Conceptual Study
Get PDFA conceptual study was carried out in respect of construction industry and Human Resource Management (HRM) and to carry out the study was caused by little theoretical and empirical research done, contextual gap and intellectual curiosity of the researchers. Five research questions were formulated and five research objectives were established in line with them. Construction industry was understood as an industry which is significantly different from other industries and a number of specific types of personnel work in the industry. A sufficient functional framework of HRM was developed for the purpose of adopting to describe and explain the generic role of HRM in an organization. The generic role of HRM in organizations engaged in construction industry was outlined and a number of specific considerations in managing personnel working in construction industry were revealed. It is believed that the paper is of theoretical importance and provides some useful insights to practicing managers in the construction industry, particularly in Sri Lanka
Doing research as a student
Get PDFOver the years, I have worked in a variety of research groups and learnt from great scientists with different approaches. There is no 10-step plan for success in research, particularly when you are researching the unknown! But there are many paths to leading a rewarding career in scientific research and adopting practices from successful scientists has helped me navigate my own career. Here, I compile some of the advice on doing research that I explicitly or implicitly received during my undergraduate, graduate, postdoctoral, and faculty years and use to this day. This is the same advice I give my own students. Some of these points are fairly obvious; others I wish I had implemented earlier in my own career. There are also articles in the scientific literature on doing research and publishing and presenting your results that are great reads; one example is cited here https://doi.org/10.1002/adma.200400767
Sustainability: Thinking Wide
Get PDFMy first feelings of the theme “Sustainability in the rubber industry”, were exciting and somewhat intriguing. Much has been conceived, conceptualized, discussed deliberated, implemented and various disciplines have emerged on sustainability, which are sometimes, overwhelming to a professional of the older generation. A wide array of theories, disciplines, and technologies have come up during the last 30 years in this area, reminiscing of the eras of 5S and ISO and Lean Management in the early 90s, which took the business and industrial community by storm. I must honestly admit that my experience, in the tyre industry and its sustainability in areas such as material development, (including Nanomaterials), green design and processing technologies, greener technologies and breakthroughs in EVs, is minimal and hence I prefer to leave it to the professionals, and endeavor to share some of my thoughts in this topic of contemporary interest. Another reason for my excitement is the status of affairs in the economic downturn in Sri Lanka and the hardships which we as Sri Lankans are personally experiencing at the moment. Indeed, we are not alone in this predicament and practically every nation is going through unprecedented difficulties, although Sri Lanka is one of the worst affected. Lack of focus, foresight and the inability to comprehend hindsight and not implementing and monitoring practical solutions and corruption are the reasons for not being in a sustainable position for any country, and this applies equally well to business organizations as well.
A little over two years ago I penned an article in Tyre Trends on “Sustainability or Vulnerability” at the peak period of the Covid-19 pandemic. The focus of the article was on the relevance of integrating traditional wisdom with modern strategies for sustainability, especially in countries like India and Sri Lanka, which possess a vast extent of collective consciousness accumulated for nearly 4000 + years, and the vulnerability of over-dependence on Western Models based on consumerism.
Milton Friedman, the American economist and statistician who received the Nobel Prize in 1976 for his research on consumerism argued in his famous essay that the social responsibility of business is to increase its profits for its shareholders and concluded profit maximization is justified for the risks taken by the investor. This statement made fifty years ago remains polarizing in today’s context; we cannot find fault with entrepreneurs who adopt a strategy of maximizing the use of resources for the maximization of business profits, since after all profit is not such a dirty word as first Prime minister of India, Shree Jawaharlal Nehru once stated. Profit motivation and maximization have been the driving force throughout the four industrial revolutions, resulting in enhancing the quality of life in most countries of the world; especially in what are called the developed countries