Browsing by Author "De Silva, R."

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Apoferritin and Dps as drug delivery vehicles: Some selected examples in oncology
(Biochimica Et Biophysica Acta (BBA), 2022) Kuruppu, A. I.,; Turyanska, L.; Bradshaw, T. D.; Manickam, S.; Galhena, B. P.; Paranagama, P.; De Silva, R.
Background: The ideal nanoparticle should be able to encapsulate either pharmaceutical agents or imaging probes so that it could treat or image clinical tumours by targeting the cancer site efficiently. Further, it would be an added advantage if it demonstrates: small size, built in targeting, biocompatibility and biodegradability. Ferritin, which is an endogenous self-assembling protein, stores iron and plays a role in iron homeostasis. When iron atoms are removed apoferritin (AFt) is formed which consists of a hollow shell where it can be used to load guest molecules. Due to its unique architecture, AFt has been investigated as a versatile carrier for tumour theranostic applications. DNA-binding protein from starved cells (Dps), which also belongs to the ferritin family, is a protein found only in prokaryotes. It is used to store iron and protect chromosomes from oxidative damage; because of its architecture, Dps could also be used as a delivery vehicle. Conclusions: Both these nano particles are promising in the field of oncology, especially due to their stability, solubility and biocompatibility features. Further their exterior surface can be modified for better tumourtargeting ability. More studies, are warranted to determine the immunogenicity, biodistribution, and clearance from the body. General perspective: This review discusses a few selected examples of the remarkable in vitro and in vivo studies that have been carried out in the recent past with the use of AFt and Dps in targeting and delivery of various pharmaceutical agents, natural products and imaging probes in the field of oncology.
Facile, green approach for aqueous methylene blue dye adsorption: Coconut vinegar treated Trema orientalis wood biochar
(Environmental Engineering Research, 2022) Udawatta, M. M.; De Silva, R.; De Silva, D.
Biochar is widely utilized in low-cost water treatment. However, chemicals used in most of the recorded activation techniques are corrosive, may cause secondary pollution, and not accessible by rural communities, reducing their value of being cost-effective. In this study, Trema orientalis wood biochar (WB) was successfully activated with natural coconut vinegar employing a facile technique to produce a green adsorbent for efficient aqueous methylene blue (MB) removal. Batch studies showed a three-fold higher MB adsorption capacity of coconut vinegar treated wood biochar (CVWB) compared to WB. Percentage removal ranged between 98-79% at lower dye concentrations (50-100 mg/L) and 79-48% at higher dye concentrations (100-300 mg/L). Isotherm data best fitted to the Freundlich model. Kinetic data fitted to both pseudo second order and intraparticle diffusion models, suggesting that the adsorption was governed by a pore filling mechanism with predominant electrostatic attractions, and the reaction rate was diffusion controlled. FTIR, XPS, and water contact angle measurements confirmed increased surface oxygenated groups of CVWB. XPS showed a three-fold increase in O/C atomic ratio. BET and AFM studies gave evidence to the increased porosity. Therefore, the enhanced MB adsorption capacity of CVWB was attributed to both the increased surface oxygenated functional groups and porosity.
Framework for Flower Gender Recognition Using Machine Learning.
(8th International Conference on Business & Information ICBI – 2017, Faculty of Commerce and Management Studies, University of Kelaniya, Sri Lanka., 2017) De Silva, R.; Gunasinghe, H. N.
This paper proposes a framework that can be used to identify the gender of imperfect flowers. One such application of gender identification of flowers is artificial pollination in large farmlands. The study reviews the literature on flower detection, flower recognition and its applications as well. Automatic gender identification of a flower is a branch of flower recognition that the researchers have not considered yet. The challenge in any automatic flower gender identification method is that the accuracy should be nearly 100 percent, as the maximum error rate of pollination attempts is twice that of identification. Our framework is based on building mathematical models of the structure of floral organs of imperfect flowers. It uses low-resolution images captured through cameras on aerial or mobile robots. Finally, it proposes to apply image processing and machine learning models together with image classification techniques to identify the gender of a given imperfect flower.
Identification of Water Stress of Plants Using Image Processing.
(8th International Conference on Business & Information ICBI – 2017, Faculty of Commerce and Management Studies, University of Kelaniya, Sri Lanka., 2017) De Silva, R.; Senanayake, P. A.
Low Leaf Water Content (LWC) levels in plants lead to water stress, and the leaves become wilted. Most farmers use slight wilting as the visual indicator to water their plants. Though the researchers have studied LWC of plants extensively using remote sensing and complex methods, the agricultural industry cannot use them as they are complex and costly. This paper presents a simple method of recognizing water stress of leaves using leaf images taken by a smartphone. Our initial experiment on a large sample of mung bean leaves indicates that RGB values of images are related to water stress. The method would be beneficial to the agricultural industry as once further developed; it could be used to determine the watering time point of plants. The process can be automated by capturing the images by a camera mounted on a land or an aerial robot and processing them online.
Impact of Customer Orientation on Brand Equity with Reference to Sri Lankan Airlines
(International Postgraduate Research Conference 2019, Faculty of Graduate Studies, University of Kelaniya, Sri Lanka, 2019) De Silva, R.
Maintaining positive customer orientation is highly significant to build the brand name of a particular product or service in today’s highly-competitive market. Customer buying behavior and response towards a product or service are highly associated with the brand. Consequently, brand equity is considered as one of the key approaches to target the potential customer as it reflects the real value that a brand name holds. Srivastava (2015) defined that brand equity is the added value endowed on products and services. It may be reflected in a way as consumers see, think, feel and act towards a particular brand. Sri Lankan Airlines has managed to keep up its brand by focusing on customer orientation in the airline industry. Considerably, the Airline has reduced airfares to attract more customers. Further, Sri Lankan airline has been continuously working on the quality of flight by redesigning the interior, especially the business class cabins with first-class recliner seats for added comfort. Therefore, the purpose of this study is to examine the impact of customer orientation on brand equity with reference to Sri Lankan airlines. Here, the researcher considered brand equity as a dependent variable and customer orientation as an independent variable that has three dimensions as customer relationship management, service quality and price of the service. The sample size of the study is 75 respondents who used Sri Lankan airlines during the period of December 2017 to May 2018. The researcher used a convenience sampling method in order to collect data from 75 passengers. The findings of the study are based on primary data which was collected through a questionnaire. Secondary data were collected through published research papers, journals, reports, websites, and guidelines to support the study. There are no gender biases in the study as 53% of the respondents were male and 47% of the respondents were female. The researcher used multiple linear regression analysis to examine the collected primary data. The outcomes of the study reveal that customer relationship management, service quality, price of the service are significant factors, where p values are less than 0.05. Moreover, findings of the study show that 1-point increases customer relationship management, service quality, price of the service corresponding to 0.038, 0.057, 0.080, increases on brand equity. It also indicates that service quality has a higher impact than customer relationship management and price of the service by comparing the standardized coefficients (beta = 0.732 versus beta = 0.063 and 0.096). Apart from these, respondents are averagely satisfied with the price of the service and customer relationship management. Therefore, it suggests that Sri Lankan airlines should offer reasonable low-price tickets than the competitors’ prices and vary the prices according to seasons and situations. It’s vital that they build, maintain and improve strong and positive customer relationships in a manner that the customers will recommend the airline to their friends and family
Pollen biology and reproductive ecology of selected paleotropical dendrobiums and its commercial hybrids.
(Journal of Pollination Ecology, 2023) De Silva, R.; Herath, H.; Ratnayake, S.; Attanayake, R.; Senanayake, P.
Understanding the reproductive biology is of great importance in the development of novel hybrids in ornamental plants. Pollen fitness-related traits are crucial for the pollination success in any plant species including dendrobiums. The aim of the study was to determine and compare the fitness traits of ten commercial Dendrobium hybrids and two indigenous Dendrobium species, D. crumenatum and D. anosmum found in Sri Lanka. We measured pollen viability, pollen germinability, and fruit production after controlled pollination. The effect of storage temperature on D. crumenatum pollen viability was evaluated to establish a suitable pollen storage method to improve future breeding programmes, as the flowering of dendrobiums is seasonal. The reproductive ecology of selected dendrobiums was studied by the observations of visits of natural pollinators and by assessing floral morphology to predict their potential pollinators. Six commercial hybrids had non- viable pollen while D. crumenatum showed the highest pollen germinability under both in vivo and in vitro conditions. Ninety percent of the commercial hybrids failed in vitro pollen germination whereas under in vivo conditions 50% were successful. Self-incompatibility in D. crumenatum was observed in both hand-pollination and under natural pollination. Pollen of D. crumenatum can be stored for two weeks at 9°C maintaining viability and germinability. Selected dendrobiums have shown adaptations to melittophily, suggesting the pollination by bees. Findings indicated a reduction of male fitness in most of the commercial Dendrobium hybrids and a higher fruit set is seen in selfing than cross-pollination. The present study provides information for developing conservation strategies and future hybridization programmes in paleotropical dendrobiums.
Surface modification of Trema orientalis wood biochar using natural coconut vinegar and its potential to remove aqueous calcium ions: column and batch studies
(Environmental Engineering Research, 2021) Udawatta, M.; De Silva, R.; De Silva, D.
Recent investigations have revealed the harmful health effects of elevated calcium levels in drinking water. Chemically activated biochar is the most popular option for low-cost cation adsorption. However, most of these chemicals are hardly available for rural communities, corrosive, and difficult to handle by unskilled personnel. This study aimed to determine the ability of natural coconut vinegar, a common mild acid, to activate Trema orientalis wood biochar pyrolyzed at 300˚C (BC) as a facile, safe, and low-cost approach for aqueous calcium ion (Ca2+) removal. Column tests showed a two-fold increase of Ca2+ adsorption capacity and a ten-fold increase of Ca2+ retaining capacity of BC after activation with vinegar. The isotherm results were well correlated with the Langmuir model. The maximum Langmuir adsorption of the activated biochar (BC-A) was 9.96 mg/g. Ca2+ amount was determined using flame photometry. EDX analysis showed that the O/C ratio of BC increased from 0.07 to 0.13 after activation. FTIR and wettability studies showed increased oxygenated functional groups on the BC-A surface. The authors suggest a possible acid-catalyzed hydration of the C-O-C bridges of the biochar, introducing new hydroxyl/carbonyl/ester/carboxylic/lactone groups to the biochar surface due to the vinegar activation, enhancing Ca2+ adsorption through chemisorption.