Browsing by Author "Rupasinghe, Thilini"

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Anti-microbial Nanohybrids Based on Naturally Derived Citric Acid Intercalated Layered Double Hydroxides
(Kuruppu et al/ Current Scientia, 2021) Kuruppu, Shashikala; Rathnayake, Upendra; de Silva, Madhavi; Rupasinghe, Thilini; Sandaruwan, Chanaka
Currently, there is an increased demand for advanced food packages, which can significantly increase the shelf life of food items. In the current context, it is envisaged that nanotechnology has the potential to address stability, toxicity, shelf-life, and low-cost issues of antimicrobials associated with the packaging industry. Antimicrobial nanocomposite systems are believed to be more efficient than their microscale counterparts due to the high surface area to volume ratio and quantum mechanical involvement in deciding their properties. As a result of high surface area, they are able to attach more copies of microbial molecules and cells, thus reducing the quantity of material required while significantly improving their activity. This study focuses on the development of slow-release antimicrobial material based on natural citrate (α-hydroxycitrate) intercalated layered double hydroxide (LDH) nanohybrid. Natural citrate ions available in Citrus aurantifolia (lime) were extracted by a simple chemical method and intercalated into Mg-Al-Layered Double Hydroxide following a one-step co-precipitation method. Successful intercalation of the citrate ion was confirmed by powder X-ray diffraction (PXRD) and Fourier transform infrared (FTIR) spectroscopic analysis. Release kinetics of resulted nanohybrid was studied and compared using different release kinetic models. Antimicrobial properties of this novel nanohybrid were confirmed against two common food pathogens, Colletotrichum gloeosporioides and Saccharomyces cerevisiae, and the results were compared against sodium benzoate, which is the commonly used commercial antimicrobial agent in the food industry. Successful intercalation of natural citrate ions into LDH and its activity against the tested microbes show the potential of using it as a slow-release nanohybrid material in many food-related applications.
A conceptual model to adapt microlearning to design digital teaching and learning process in higher education
(Dublin City University (DCU), Dublin, Ireland, 2023) Senadheera, Vindya; Ediriweera, Dileepa; Rupasinghe, Thilini
Microlearning is an innovative pedagogy that is practiced in current higher education. It is the method of learning through small-sized, well-organized learning units and short-term learning activities (Hug, 2005; Allela, 2021). Each microlearning unit is designed to achieve a single learning objective (Wagner, 2002). A systematic review and meta-analysis conducted on the effects of microlearning in academic performance of students has showed a higher academic performance when microlearning is used compared to the traditional learning (p = 0.03). The overall mean difference in academic performance in relation to post-test scores in theoretical examinations between microlearning and traditional learning groups has been 12.6 (95% CI: 1.2 - 23.9) (Senadheera et al, 2022c). This can be attributed to reducing cognitive load, providing flexible learning environment, promoting self-directed learning and by providing timely feedback (Senadheera et al, 2022c). Currently, university teachers are working towards re-designing the traditional teaching and learning activities (TLA) to digital courses using digital pedagogies, to address the learning needs of current students. Undoubtedly, this digital-transformation of formal higher education should be accompanied by a sound conceptual model to provide a meaningful education. The aim of this paper is to present a conceptual model to adapt microlearning to design digital teaching and learning process in higher education. A comprehensive analysis of literature was carried out in order to identify the components that should be integrated to adapt microlearning, to achieve the best outcomes in relation to performance and students’ satisfaction. Accordingly, the ‘CAA model’ was designed which is presented in Figure 1.
Development of a Household Washing Liquid for the Efficient Removal of Pesticides Residues in Vegetables and Fruits using Natural Substances
(Faculty of Computing and Technology, University of Kelaniya, Sri Lanka, 2021) Embogama, Manjali; Wickckramaarachchi, Harshani; Sonalee, Nimesha; Rukmal, Tharindu; Rupasinghe, Thilini
Pesticides are chemical or biological agents that are used in agriculture to minimize plant diseases, insect, pests and weeds. In the current Sri Lankan context, the commercial production of fruits and vegetables is extremely dependent on the regular usage of pesticides. Farmers tend to use pesticides more than the recommended amounts to achieve higher harvest by reducing the crop lost due to pests, insects and weeds [1, 2]. As a consequence, excessive pesticides residues have been detected on the surface of the vegetables available in the Sri Lankan market. According to literature, accumulated pesticide residues in food products have been associated with a wide variety of human health hazards, ranging from short-term effects to long-term health issues such as neuron problems, cancers, immune system deficiency and inborn deformities [1,3]. Therefore, it is significantly important to remove pesticide residues from fruits and vegetable before consumption. Current practice in most of the households in Sri Lanka is washing vegetables and fruits using tap/well water to remove pesticides. However, using tap water is not an effective method as it is not sufficient to remove most pesticide residues. Hence, this study focuses on developing a biosafe, effective and easily applicable washing liquid to remove pesticide residues using natural substances. Chlorpyrifos which is one of the mostly used pesticides in Sri Lanka, was selected as the model pesticide and the removal efficiency of this pesticide by natural substances such as vinegar, lime, turmeric and tamarind was investigated using computational simulations. The main hypothesis was that the efficiency of removal would depend on the interaction between the biogenic substance and Chlorpyrifos [4]. Therefore, in the computational study the interaction that could occur between the active chemical of the biogenic substance and Chlorpyrifos was predicted and the Spartan software was used to obtain information about structure, relative stabilities, and properties of the predicted product. Further, the potential energy of bond between acid substances and chloropyrifos was also calculated using Spartan software. The stability of the product formed between Chlorpyrifos and citric acid (lime) resulted to be -948.98 kJ / mol while that of curcumin (turmeric) and acetic acid (vinegar) resulted to be -472.69 kJ / mol, -286.73 kJ / mol respectively. According to the hypothesis, citric acid can be named as the most suitable candidate as it results in a product with the lowest potential energy. Overall, the results from the theoretical study provides a good basis for the selection of natural substances for future laboratory studies to develop a washing liquid with a higher efficiency of pesticide removal.
Impact of ZnO NPs on In Vitro Germination and Growth Characteristics of Rice (Oryza sativa)
(Faculty of Computing and Technology (FCT), University of Kelaniya, Sri Lanka, 2021) Perera, Sujani; Rupasinghe, Thilini; Wijenayaka, Lahiru
A key feature of contemporary nanotechnology is the successful utilization of nanotechnological concepts in agriculture, for applications such as enhancement of the efficiency of crop production through improved seed germination & growth, smart fertilizers, smart pesticides etc. Effect of different nanoparticles (NPs) such as TiO2, Ag, Si, Au, Cu, Zn and ZnO on seed germination have been studied in literature for crops such as canola, mung beans, onions, fenugreek and watermelon. Current study focuses on investigating the impact of ZnO NPs on the seed germination and growth of rice (Oryza Sativa). ZnO is a non-toxic NP and has the potential to boost the yield and growth of food crops. According to literature, ZnO NPs have been used to enhance the seed germination in different plants such as mung beans, peanut and black gram. Herein, ZnO NPs were synthesized by a wet chemical method by mixing ethanolic solutions of NaOH and Zn (CH3COO)2·2H2O.The morphology of the synthesized ZnO NPs was studied using Scanning Electron Microscopy (SEM) and synthesized ZnO NPs exhibited a spherical shape with a diameter ranging from 65 nm to 95 nm, with an average diameter of (73±2) nm. The impact of ZnO NPs on germination and growth of rice was studied under different NP concentrations (0- 2000 mg/L) for Sudu samba and traditional rice varieties, Suwandel and Madathawalu. Further, the growth characteristics were investigated by measuring the root length and the shoot length of rice seeds. A significant enhancement of seed germination was observed in all three rice varieties after treating with ZnO NPs. Sudu Samba seeds showed a 7.3 % enhancement of seed germination (at 500 mg/L ZnO) while Suwandel and Madathawalu showed an enhancement of 20 % and 17% respectively. This can be attributed to the ability of ZnO NPs to penetrate through the cell wall and release targeting genes to specific cellular organelles to boost the cell division. As Zinc is an enzymatic component, it has the ability to influence secretion of indole acetic acid (IAA) which important to regulate plant growth and when the level of IAA is increased, it causes an effective response in seed germination. Interestingly, no significant difference in root length and shoot length was observed for Madathawalu while, a negative effect was observed for Sudu samba and Suwandel at 7 days. Further investigations with varying ZnO concentrations and other types of traditional Sri Lankan rice varieties are currently ongoing to gain more insight into the phenomena observed above.
Possibility of ceylon tea waste conversion to biochar –a short review
(The Library, University of Kelaniya, Sri Lanka, 2023) Jayathilake, Chamishka; Samarasekere, Pradeep; Rupasinghe, Thilini
Studying and comprehending factors influencing academic performance is crucial for gaining valuable insights into the success of undergraduates. In this systematic review, the correlation between gender and undergraduate academic performance across various fields of studies in Sri Lankan universities was comprehensively studied. The data from multiple studies conducted between 2008 and 2022 in different disciplines, including Science, Management, Medicine, Agriculture, and Information Technology, was analyzed systematically. Quantitative, qualitative, and mixed-method research published in English exploring the impact of gender on academic performance were studied. The review involved 16 research studies comprising 35,608 individuals from several state universities. The data analysis showed a complex picture of gender inequalities in academic performance, with several significant trends and consequences emerging. A consistent pattern emerged, with 75% of the studies demonstrating that female students excel academically across various disciplines, while the rest exhibited no gender differences in performance. These findings underscore the critical need to promote gender equity and eliminate gender-based gaps in Sri Lankan higher education. Conducting in-depth studies across all degree programs and universities in Sri Lanka is recommended to gain a more comprehensive understanding and investigate the relationship between gender and academic performance.