ICAPS-2021

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Human in the loop design for intelligent interactive systems: A systematic review
(Faculty of Science, University of Kelaniya, Sri Lanka., 2021) Arambepola, N.; Munasinghe, L.
It is undeniable that modern computers are incredibly fast and accurate. However, computers cannot ‘think’ (act intelligently) as humans unless it is trained to learn from the past knowledge. Despite their intelligence, humans are comparatively slow in computational tasks. However, the combination of the computational capacity of computers and human intelligence could produce powerful systems beyond the imagination. This concept is called Human-in-the-Loop (HITL) where both human and machine intelligence support the creation of Machine Learning (ML) models. HITL design is an emerging technology which is used in many domains such as autonomous vehicle technology, health systems and interactive system implementations. In this research, we systematically reviewed past research of HITL systems with the objectives of identifying key benefits and limitations of the HITL design. This systematic review was conducted by analyzing 68 research papers published in top-ranked journals and conferences during the past decade. Moreover, the papers were selected using keyword-based searching and references of the most cited HITL research papers. The PRISMA model was used to exclude irrelevant papers, and keyword-based clustering was used to identify the frequent keywords in the selected papers. Although the HITL design often improves the performance of intelligent interactive systems, there are certain drawbacks of this concept when compared to fully manual or fully automated systems such as making decisions with emotional bias and being unable to take actions when demanded. Thus, we comprehensively discuss the approaches proposed by the recent researchers to overcome some of the issues of the existing HITL designs.
Data Envelopment Analysis for efficiency assessment of state universities and selected faculties in Sri Lanka
(Faculty of Science, University of Kelaniya, Sri Lanka, 2021) Wijesundara, W. M. T. H.; Prabodanie, R. A. R.
Efficiency of public universities is a widely discussed concern which is of significant importance to the well-being and economic prosperity of a developing nation. It is a key performance indicator of an education system which needs to be monitored and improved continuously. Although the efficiency of universities has been widely studied in some countries, no efficiency comparison research has been conducted in the Sri Lankan context. The main objective of this study was to measure the relative efficiencies of the state universities in Sri Lanka from 2017 to 2019 using Data Envelopment Analysis (DEA). Since the universities have different compositions of faculties, the relative efficiencies of Science, Medical and Engineering faculties were separately evaluated. The input variables considered in the DEA models were annual expenditure, academic staff and non-academic staff. The output variables used were graduate output, total enrolments, number of publications in indexed journals, and Webometric ranking. The input- oriented variable returns to scale option in DEA was used, assuming that the inputs can be controlled. A freely available Excel add-in named DEA Solver was used in the analysis. The results of the overall efficiency comparison showed that eight out of fifteen state universities were constantly performing efficiently from 2017 to 2019 while two universities were constantly inefficient during the same period. Overall, 73% of the universities were efficient. The average efficiency scores across all universities from 2017 to 2019 were 0.9681, 0.9707 and 0.9409 respectively. Average efficiency scores of Science faculties for the same period were 0.8127, 0.7928 and 0.8053 respectively. Medical faculty comparison indicated efficiency scores as 0.742, 0.9332 and 0.8126 respectively from 2017 to 2019 while it was 0.9473, 0.9477 and 1 respectively for Engineering faculty comparison. Over the total period, the larger number of non-academic staff has been the main reason for the inefficiency of universities, and the results suggest that it should be reduced in a range from 0.7% to 40%. The number of efficient Science faculties was decreasing from 2017 to 2019. Efficiency comparison of engineering faculties alone indicated that most of them (83%) were efficient whereas only 54% of the medical faculties were efficient according to the comparison. The outcomes of this study are thoroughly based on an analysis performed using the DEA method with a selected set of variables, and owing to the limitations in DEA method, variables and data, the results may not reflect the actual efficiency levels of the universities. However, the study provides an understanding of some inequities in resource allocation and/or utilization among public universities.
Atmospheric chemical composition of bulk precipitation of the vicinity of oil refinery in Sapugaskanda, Sri Lanka
(Faculty of Science, University of Kelaniya, Sri Lanka, 2021) Karunarathna, M. M. S. T.; Deeyamulla, M. P.; Kannangara, A. T.
Rainwater quality is critical because it can be used to forecast air quality. The aim of the current study was to investigate the chemical characteristics of bulk precipitation in Kelaniya, Sapugaskanda, and Siyambalape, an area close to an oil refinery in Gampaha District, one of Sri Lanka's most densely populated and urbanized districts. Wet precipitation samples were analyzed for pH, conductivity, Na+, K+, Mg2+, Ca2+, F-, Cl-, NO3-, SO42-, Pb, Cu, Mn, Al, Zn, Ni, Cr, Cd, and Fe for a total of 18 samples between 2020 July and 2020 October. The results obtained were compared with 6 samples taken from a background area situated in Kidelpitiya, Meegoda where the anthropogenic influence is minimum. Volume-weighted average concentrations of the major ionic species present in precipitation samples were in the order of F−< K+< NO3−< Mg2+< Cl−< SO42−< Ca2+< Na+. Neutralization of the acidic species would take place due to the presence of MgCO3 and CaCO3. Other than the anthropogenic sources natural sources were also considered. When considering a marine contribution, SO42−/Na+, Ca2+/Na+, and Mg2+/Na+ ratios are higher than the reference value suggesting that contribution of sources be possible other than marine. When considering a soil contribution, SO42−/Ca2+, NO3−/Ca2+, Na+/Ca2+, and Cl- /Ca2+ ratios are higher than the reference value suggesting that contribution of sources be possible other than soil. It was also found that Al is the most predominant trace element in the area while Fe is the least (All are in metallic forms not in the ionic forms). Investigation of correlation between major ionic species and elements (Ca2+, SO42-, Al, Cu, Zn, and NO3-) in the wet precipitation samples identified probable anthropogenic sources such as heavy traffic, biomass burning, large-scale constructions, and waste incineration. The highest correlation between Na+ and Cl- is probably due to marine contribution. A comparison between the background and the study area was carried out to identify the difference between the chemical compositions of the atmosphere during the given period suggesting that the area has a higher chemical composition of the species interested rather than the background. Also, this study reveals the effect of the Covid-19 pandemic on the reduction of the chemical composition of such species of the atmosphere in the area of interest. This study reveals that the chemical composition in the atmosphere is strongly dependent on both anthropogenic and natural phenomena around the area of study.
Time series forecasting of farm gate prices of fresh coconuts in three major coconut growing areas of Sri Lanka
(Faculty of Science, University of Kelaniya, Sri Lanka, 2021) Perera, D. H. N.; Waidyarathne, K. P.; Jayasundara, D. D. M.; Hewaarachchi, A. P.
Coconut is a perennial crop with important food value and other endless uses for human beings. Hence, this has led to the emergence of a diversified set of industrial activities. All over the world, Sri Lanka is the fourth largest coconut producing country. The major part of Sri Lanka's coconut production comes from the Coconut Triangle, which consists of Puttalam, Kurunegala and Gampaha districts. Forecasting coconut prices can provide critical and useful information to coconut growers making production and facing real situations and uncertainties of the coconut industry. The objective of this study is to build accurate univariate or multivariate time series models to forecast the farm gate prices of fresh coconut in three major coconut growing areas (Puttalam, Kurunegala, and Gampaha) of Sri Lanka. This study evaluated the times series data on monthly farm gate prices of fresh coconut in the selected districts from January 2009 to December 2019.This paper examines three time series modelling approaches, Autoregressive Integrated Moving Average (ARIMA), Generalized Auto Regressive Conditional Heteroskedasticity (GARCH) and Vector Error Correction (VEC) model. Root Mean Squared Error (RMSE) and Mean Absolute Percentage Error (MAPE) were used to evaluate the performance of fitted models. As the univariate time series approach, ARIMA (1,1,5) and ARIMA (2,1,2) were identified as the better models for forecasting prices of Puttalam and Gampaha based on Akaike Information Criterion (AIC) where RMSE (5.83,5.77) and MAPE (12.60,10.99) respectively. In contrast to the other two districts, Kurunegala showed a non-constant variance with the time, hence GARCH model approach was tested for the particular data series. It was found that all model coefficients were not significant in the GARCH model thus univariate models were not applicable for Kurunegala District. Therefore, multivariate time series model was carried out to find a suitable model. First, the Johansen co-integration test was applied and the results proved that there were two co-integration equations at 5% level of significance. As there were significant cointegration detected between series, VECM was applied in order to evaluate the short run properties of the cointegrated series. According to the lag selection criteria, lag 7 was selected as the optimum lag value. Considering the VEC models, the RMSE and MAPE in Puttalam, Kurunegala and Gampaha were 6.30,5.41,5.85 and 12.81,10.76,11.14 respectively. Results revealed that VECM approach worked well for forecasting Kurunegala price series. Even with long-term equilibrium relationship exists between series, VECM approach was less accurate in defining the relationship in comparison to ARIMA models for Puttalam and Gampaha price series. Therefore, that the study recommends the ARIMA models as the appropriate models to forecast the monthly farm gate prices of fresh coconut in Gampaha and Puttalam districts.
An approximate solution to Lane-Emden equation of the polytrophic index three by using Differential Transform Method
(Faculty of Science, University of Kelaniya, Sri Lanka, 2021) Aththanayaka, A. M. S. K.; Wimaladharma, N. A. S. N.
Lane-Emden equation is a second order dimensionless non-linear ordinary differential equation which can be used to describe internal structure of a star, the thermal behaviour of a spherical cloud of gas, isothermal gas spheres etc. Self-gravitating spheres of plasma, such as stars, can also be described approximately by using these equations. Lane-Emden equation was solved by using Adomian Decomposition Method (ADM), Homotopy Analysis Method for some values of polytrophic index n. There are exact, analytical solutions for Lane-Emden equation in particular values n = 0, 1, 5. Since its non-linearity, the exact solutions cannot be found easily. Differential Transform Method (DTM) is an iterative method with a Taylor series solution gives good approximation in very small region. DTM can be applied for both linear and nonlinear nth derivative functions. In this research, a numerical solution to Lane-Emden equation with n = 3 has been found by using Differential Transform Method. To increase the range of convergence of the solution, the Pade approximation has been applied. Pade approximation is a ratio of two McLaurin’s expansion of the polynomials. The obtained solution for Lane-Emden equation has been compared with the solutions obtained by using the Fourth Order Runga-Kutta (RK4) method, ODE45 and Forward Euler method, which are effective and accurate methods for solving differential equations. The Einstein-Maxwell equations for a static spherical distribution of matter which is called Electrically Counterpoised Dust (ECD) under gravitational attraction and electrical repulsion can be simplified to the Lane-Emden equation when n = 3. It has been shown that the mass of a sphere of electrically counterpoised dust is an increasing function of its radius and it has a maximum value. Since the solution obtained gives us a physically acceptable result, it can be justified that the obtained solution using DTM is acceptable and gives better approximate solution with the form of a polynomial for linear and nonlinear differential equations.
The women’s level of awareness regarding shoulder surfing attacks with reference to harassments occur in public transportation
(Faculty of Science, University of Kelaniya, Sri Lanka, 2021) Samarasinghe, T.D.; Sellahewa, W.N; Samarasinghe, N.K
Public transportation is a widely used convenient mode of transport in Sri Lanka. People at all levels of society use this mode of transportation to achieve their daily commute. With the demand for public transport, the occurrence of incidents catering to violence concerning women using this service has also increased significantly. Therefore, revitalizing the safety of women using public transportation has become a major obstacle. Although this violence is classified as physical and psychological abuse, with the advancement and the misuse of technology, the amount of violence that women face has considerably increased. These technological misleads have helped to put a different texture to the ways of harassment. The objective of this study is to examine the level of women’s awareness about shoulder surfing attacks that transpires to them while using public transportation. Preliminary data was gathered by distributing a well-structured google survey consisting of open and close-ended questions. Convenience sampling technique was used to facilitate sample selection as the questionnaire was dispersed amongst 110 women who belonged to age groups from under age of 20 to over 60. Subsequently, 100 satisfactory responses were accumulated. The data which gathered from over 60 category had to be emitted due to the inaccurate and beleaguered answers which were provided. This issue can be described as a limitation in terms of the data collection technique. Based on the findings, Sri Lankan women (55% from the sample) who consume public transportation are unaware of shoulder surfing attacks and have null comprehension to state whether they have been a victim of this attack. Only 45% of respondents stated that they had a clear understanding that they have experienced or are aware of shoulder surfing attacks. They have encountered Password breaching, social media accounts hacking, identity theft and stealing public photos as post shoulder surfing attacks. Many respondents indicated that they have no acquaintance as to where to report if an incident similar to shoulder surfing occurred. The respondents in use numerous actions to avoid the aforementioned post shoulder surfing attacks such as deactivating the social media accounts, deleting publicly post photographs. The “today” of women has changed drastically due to the rapid transformation and spread of technology which is intertwined with timely commutes. Technology and social media have become an integral part of life. To avoid shoulder surfing attacks the research recommends using biometric security systems such as fingerprint scanners and face detection technologies to provide a quick, easy, and secure way to access accounts without revealing passwords. Additionally recommends conducting workshops to educate women about shoulder surfing, how to identify attacks and respond to them. The outcome of workshops should be taken into consideration when formulating strategies to prevent and intervene in technological harassment which women face while accessing social media in public transportation. Nurture social engineering awareness, directing women to use technology and public transportation services safely. Technological Violence and harassment aiming at women who use public transportation must be engaged solemnly stopped by the authorities.
Herbicidal properties of invasive alien plants Dillenia suffruticosa and Prosopis juliflora against Brassica juncea and Pennisetum polystachion
(Faculty of Science, University of Kelaniya, Sri Lanka., 2021) Kaushalya, W. D. D.; Bandara, N. C.; Damunupola, J. W.; Madawala, H. M. S. P.; Jayasuriya, K. M. G. G.; Wijesundara, D. S. A.; Bandara, B. M. R.
Synthetic pesticides can cause deleterious effects on human health and the environment. The rapid spread of invasive alien plants (IAPs) threatens biodiversity and the natural and semi-natural ecosystems. A strategy to address these problems is to develop eco-friendly plant-based pesticides from IAPs. In this study, the two IAPs, Dillenia suffruticosa (Griff.) Martelli. and Prosopis juliflora (Sw.) DC., were evaluated for their herbicidal properties against Brassica juncea (L.) Czern. (Bj) and Pennisetum polystachion (L.) Schult. (Pp). The dry leaf powders of IAPs, were separately extracted into dichloromethane-methanol (1:1) using a bottle extractor. The leaf powders and the concentrated leaf extracts were assayed for their inhibitory effects on seed germination and early seedling growth (shoot length, root length and biomass) of Bj and Pp using a Petri dish assay; 2-methyl-4-chlorophenoxyacetic acid (MCPA) and glufosinate were used as positive controls and distilled water and aqueous dimethyl sulfoxide as negative controls. Each treatment was done on 25 seeds in four replicates, in three trials. The IC50 values of the leaf powders and extracts expressed in equivalent amount of leaf powder for the inhibition of seed germination of Bj and Pp were as follows: 3.70 ± 0.38 and 3.10 ± 0.52 mg cm-2 (D. suffruticosa leaf powder against Bj and Pp, respectively); 1.55 ± 0.05 and 0.23 ± 0.06 mg cm-2 (P. juliflora leaf powder against Bj and Pp, respectively); 1.47 ± 0.07 mg cm-2 (D. suffruticosa leaf extract against Bj); 1.19 ± 0.53 mg cm-2 (P. juliflora leaf extract against Bj). Both IAPs were more effective on Pp than Bj (ANOVA, F = 70, p < 0.001). According to the results of the Kruskal- Wallis test, the leaf powders of P. juliflora (at 3.52 mg cm-2, 2 = 25.7, p < 0.001) and D. suffruticosa (at 17.62 mg cm-2, 2 = 24.3, p < 0.001) and the leaf extracts of P. juliflora (at 5.56 mg cm-2, 2 = 26.2, p < 0.001) and D. suffruticosa (at 8.27 mg cm-2, 2 = 25.6, p < 0.001) displayed more potent inhibitory effects on seed germination than glufosinate (at 4.4 µg cm-2) and MCPA (at 10.6 µg cm-2). Growth parameters of Bj and Pp decreased with increasing concentrations of leaf powders and extracts of IAPs (one-way ANOVA, p < 0.05). The leaves of P. juliflora and D. suffruticosa can be exploited to develop eco-friendly herbicides.
Evaluation of nutritional composition of peel and seeds of Flacourtia indica fruit
(Faculty of Science, University of Kelaniya, Sri Lanka, 2021) Jayasinghe, J. M. H. M.; Weerasooriya, M. K. B.
Flacourtia indica is an endangered plant species with high medicinal value. The fruit has been reported as a valuable source of natural products that can treat various diseases and functional disorders. It is commonly called Ramontchi, Governor’s plum, Batoko plum, Madagascar plum and Indian plum. In Sri Lanka, it is called “Uguressa”. The nutritional content of non-edible portion (peel and seeds) is so far not reported. Hence, analysing the nutritional composition of this non-edible portion is targeted in the current study. We determined moisture, ash, lipid, fibre, protein, carbohydrate and calorie contents of peel and seeds. The results showed that the percentage of moisture, lipid, ash, fibre, protein, and carbohydrate contents of the peel powder were, 15.20±0.267, 9.277±0.165, 13.93±0.488, 9.520±0.0333, 22.41±0.53 and 29.66±0.665 respectively. The calorie value of peel was 291.8 kcal/100g.The percentage of moisture, lipid, ash, fibre, protein, and carbohydrate contents of the seed powder were 8.890±0.200, 0.6517±0.0217, 2.567±0.0246, 50.96±0.484, 17.54±0.309, and 19.39±0.520 respectively. The calorie value of seeds was 153.6 kcal/100g. Findings indicated that peel contains a higher percentage of moisture, lipid, ash, protein, and carbohydrate content than the seeds. Lipid content is very less in the seeds. Due to the presence of a significant amount of carbohydrates in fruit peels, it can be utilized as a carbohydrate source. The percentage of crude fibre content is very much higher in seeds than peel. Thus, F. indica seeds can be considered a good source of dietary fibre. Due to high protein content, both peel and seeds can be recommended for value-added food supplements with high protein content. The results of the statistical analysis showed that there is a significant difference (p <0.05) among the total moisture content (p=0.000), lipid content (p=0.000), ash content (p=0.000), crude fibre content (p=0.000), crude protein content (p=0.01) and carbohydrate content (p=0.000) in seed and peel powder. These findings indicate that, Flacourtia indica seeds and peel exhibit the potential to be developed as a functional food.
In vitro antidiabetic activity of fractionated extracts of Coccinia grandis (L.) Voigt
(Faculty of Science, University of Kelaniya, Sri Lanka, 2021) Wasana, K. G. P.; Attanayake, A. P.; Jayasinghe, J. M. S.; Weeraratna, T. P.; Jayatilaka, K. A. P. W.
The Paspanguwa herbal formulation is commonly consumed as a traditional medicine in Sri Lanka. Paspanguwa consists of five ingredients, namely the rhizome of Zingiber officinale (Inguru), leaves and stem of Hedyotis corymbosa (Pathpadagam), dried berries of Solanum xanthocarpum (Katuwalbatu), dried stem of Coscinium fenestratum (Venivalgata), and dried seeds of Coriandrum sativum (Koththamalli). The importance and objective of this study was to prove the antioxidant and anti-inflammatory properties of traditionally used decotion, Paspanguwa claimed to have. In the present study, water extracts of the individual ingredient and the Paspanguwa decoction were screened for their total soluble phenolic content (TPC), total soluble flavonoid content (TFC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, and their ability to inhibit protein denaturation (anti-inflammatory activity). The highest and the lowest TPC was seen in Coriander and ginger as 12.76 ± 1.00 and 7.89 ± 0.86 mg Gallic acid equivalent/g dry weight, respectively. The highest and the lowest TFC was seen in Katuwalbatu and Pathpadagam as 778.19 ± 1.40 and 282.14 ± 1.49 µg Catechin equivalent/g of dry weight, respectively. The lowest and the highest IC50 values for the DPPH assay was seen in Paspanguwa decoction and Katuwalbatu as 253.4 ± 8.2 and 609.7 ± 5.6 µg/mL, respectively, while the standard ascorbic acid showed 111.0 ± 6.1 µg/mL. The highest and lowest reducing power percentages were seen in Paspanguwa decoction and coriander as 94.74 ± 1.31 and 22.95 ± 0.96 while the standard ascorbic acid showed 109.89 ± 0.96. The ability to inhibit protein denaturation varied in the order of: Acetylsalicylic acid (standard) > Paspanguwa decoction > ginger > coriander > Venivalgata > Katuwalbatu > Pathpadagam at all the three concentrations (625, 1250, and 2500 µg/mL). These results suggest that Paspanguwa water extract is a good source of antioxidants with TFC and TPC with a higher ability to inhibit protein denaturation. Our findings corroborate with the previous in vitro studies of the antioxidant activity of Paspanguwa. However, our study is the first to reveal the anti-inflammatory action, total flavonoid content, and reducing power of the Paspanguwa herbal formula. Further, this study validated the use of Paspanguwa as a good source of antioxidants together with anti-inflammatory activity in traditional Ayurvedic medicine.
Surface modification of Leucaena leucocephala wood biochar using coconut vinegar
(Faculty of Science, University of Kelaniya, Sri Lanka, 2021) Udawatta, M.; Silva, R. C. L. De; Silva, D. S. M. De
Over the last few decades biochar has emerged as a popular low cost adsorbent for water treatment due to its abundance and cost-effectiveness. Number of studies have reported the efficiency of strong acids such as nitric, sulfuric, hydrogen peroxide, etc. in activating biochar. However, as these chemicals are expensive, corrosive and difficult to be handled by unskilled personnel, use of these chemicals is limited to industrial activation processes. To provide a user friendly economical activation process, this study focused to evaluate the ability of natural coconut vinegar, in activating Leucaena leucocephala wood biochar. Coconut vinegar, a common food additive, is a 4 % acetic acid solution in water (4 g acetic acid/ 100 mL vinegar, pH 2.5). Leucaena leucocephala is a common, fast-growing tree with light wood and soft foliage. It is widely used for fuelwood. In this study, air dried Leucaena leucocephala wood pieces were allowed to burn in a domestic kiln (300 ºC, 2 hours) to produce biochar. The activation of biochar was done by soaking it in coconut vinegar for 24 hours followed by oven drying (120 ºC, 3 hours). After cooling it was washed with de-ionized water and further dried in oven at 80 ºC overnight. Fourier transform infrared spectra exhibited hydration of the C-O-C bridges of the biochar surface introducing new -OH groups and the possible introduction of carbonyl/ester/carboxylic functional groups to the biochar surface after the vinegar treatment. Recently, a positive correlation has been cited among the number of Chronic Kidney Disease of Unknown Etiology patients and the levels of ground-water hardness, in Sri Lanka. Hence, the efficiency of coconut vinegar activated Leucaena leucocephala biochar in reducing calcium ions from potable water was tested. Adsorption and desorption studies carried out using column tests showed a 1.7 fold increase of calcium ion adsorption capacity and a 7 fold increase of calcium ion retaining capacity after the vinegar treatment, with compared to the non-activated biochar. Calcium content in solutions was measured using flame photometry. Calcium adsorption capacities of non-activated biochar and activated biochar determined by column tests ranged from 3.10-3.82 mg/g and 5.27-6.68 mg/g respectively while calcium retaining capacities ranged from 0.16-0.22 mg/g and 1.28-1.4 mg/g respectively. Batch studies matched with both Langmuir (R2 = 0.9761) and Freundlich (R2 = 0.9785) isotherm models. Maximum adsorption, qm was calculated as 23.8 mg/g using Langmuir equation. This study concludes that Leucaena leucocephala biochar can be activated using coconut vinegar to be used as a safe and cost-effective adsorbent for calcium ion removal from potable water.
Phytochemical screening and antioxidant potential of three underutilized fruit species in Sri Lanka
(Faculty of Science, University of Kelaniya, Sri Lanka, 2021) Somasiri, R. P. I. V.; Herath, H. M.; Ratnayake, R, M. C. S.; Senanayake, R. A. S. P.
Syzygium caryophyllatum (L.) Alston. (S: Dan), Cynometra cauliflora Linn. (S: Namnam) and Antidesma ghaesembilla Gaertn. (S: Bu ambilla) are three underutilized fruit species found in Sri Lanka. This research was carried out to determine the phytochemicals and in vitro antioxidant potential in methanol and acetone fresh fruit extracts of the three underutilized species. Methanolic and acetone extracts of edible parts of the ripe fruits were prepared and the presence of polyphenols, flavonoids, tannins and saponins in the extracts was studied using qualitative assays. Then, the total phenolic contents of the fruit extracts were determined by Folin-Ciocalteu method. Gallic acid was used as the standard and the results were expressed as milligrams of gallic acid equivalents per gram of fresh sample (mg GAE/g FW). The antioxidant activities of the extracts were determined using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging assay. Phenolic contents and antioxidant activities of the fruits were statistically analyzed using Two-way ANOVA and compared using Tukey’s pairwise comparison. The qualitative analysis of the extracts of the three fruits revealed the presence of polyphenols, flavonoids and saponins. Tannins were reported only from methanolic and acetone extracts of S. caryophyllatum and acetone extract of C. cauliflora. The highest total phenolic contents were recorded from the acetone extract of C. cauliflora (27.77±0.08 mg GAE/g FW) followed by the methanolic extract of S. caryophyllatum (26.93±0.09 mg GAE/g FW). The phenolic contents of both extracts of A. ghaesembilla were significantly low (2.66±0.01-3.98±0.01 mg GAE/g FW). The methanolic extract of S. caryophyllatum had the highest DPPH free radical scavenging activity (57.52±0.10%) followed by the methanolic extract of C. cauliflora (41.74±0.24%). From the two extracts of A. ghaesembilla, the acetone extract showed the highest antioxidant activity (15.88±0.52%). From the two solvents used to prepare the fruit extracts, methanol was the best for S. caryophyllatum, while for C. cauliflora both solvents would be beneficial. Acetone will be a better solvent to study the phytochemicals of A. ghaesembilla. Revealing the phytochemicals and antioxidant properties of these fruits will be useful for better utilization and commercialization of these fruits in future.
Proximate analysis on nonedible portions (fruit peels and seeds) of pomegranate cultivars grown in Sri Lanka
(Faculty of Science, University of Kelaniya, Sri Lanka, 2021) Punchipatabendi, T. I.; Weerasooriya, M. K. B.
Pomegranate (Punica granatum L., family Punicaceae), because of its high nutritional and nutraceutical value, is a very popular fruit crop among growers and consumers worldwide. Nonedible portion (peel and seed) is reported to be a rich source of biomolecules of immense health significance. Though, nutritional value of fruit juice is being reported and little is known about peel and seed. Hence, the study was targeted at evaluating proximal composition of fruit peel and seed of pomegranate cultivars, Kalpitiya hybrid, Daya and Nimali. Under proximal analysis, moisture content was analyzed using oven drying method, ash content using a muffle furnace, lipid content using Soxhlet extraction, fiber content using acid and alkaline digestion, nitrogen content using Kjeldahl distillation method and carbohydrate content was calculated using an equation. Corresponding proximal analysis values for peel were ranged from 11.3067 ± 0.017% to 15.196 ± 0.217% for moisture content, from 44.79 ± 4.37% to 58.05 ± 3.46% for carbohydrate content, from 1.2613 ± 0.01172% to 3.358 ± 0.113% for ash content, from 0.91±0.09% to 1.41 ± 0.14% for lipid content, from 11.73 ± 0.41% to 19.60 ± 0.84% for crude protein content and from 12.66 ± 1.25% to 15.23 ± 0.87% for fiber content. While corresponding proximal analysis values for seed were ranged from 7.7033±0.0893% to 8.202±0.0552% for moisture content, from 7.227 ± 0.40% to 26.54 ± 2.76% for carbohydrate content, from 1.352 ± 0.00917% to 4.008 ± 0.535% for ash content, from 16.24 ± 0.53% to 21.50 ± 1.29% for lipid content, from 16.24 ± 0.33% to 33.30 ± 4.16% for crude protein content and 28.05 ± 0.13% to 32.50 ± 1.59% for fiber content. Kalpitiya hybrid peels and seeds had the highest ash, lipid, protein and fiber content, whereas Daya peels and Nimali seeds had the highest carbohydrate content. Daya seeds and hybrid peels had the highest fiber content. Thus, study herein revealed that lipid and protein contents are higher in seeds than the peels, whereas carbohydrate and fiber contents are higher in peels than seeds. Also, peels and seeds exhibit significant percentages of nutritional values comparative to the dry weight, which bears the potential to develop into healthy food ingredients, nutraceuticals that can be used in many applications in food industry.
Can mangrove blue carbon help counteract climate change? A case study in Rekawa, Sri Lanka
(Faculty of Science, University of Kelaniya, Sri Lanka., 2021) Arulnayagam, A.; Park, J.
Blue carbon to assist climate change has gained recent attention with increasing nature-based mitigation methods. Mangrove ecosystems with their high primary productivity, efficiently sequester carbon in their anaerobic sediment. Carbon sink function of mangrove ecosystems has been acknowledged as a potential tool in climate change mitigation. However, achieving full potential of blue carbon services of mangrove ecosystems requires evidence-based research and reporting to bridge the knowledge gaps. The present study aimed to report the blue carbon potential of mangrove ecosystems in Rekawa lagoon and its’ potential contribution to mitigate climate change. Field work was conducted in December 2019, with 10m wide belt transects (n=6) laid across water-land gradient to collect data on mangrove vegetation structure and sediment organic carbon content. Mangrove species along the transect were identified, enumerated, and measured Diameter at Breast Height (DBH) for overstory trees with DBH >5cm. Sediment cores were taken along the same transect to 45cm depths and subsampled to three portions representing sediment in 15 cm intervals. Carbon in above ground plant biomass was estimated with the use of biomass based allometric equations. One portion of sediment samples with known volume was oven dried and measured for bulk density while the rest was measured for total organic carbon (TOC %) with elemental analyzer, which were later used for the calculation of sediment organic carbon (SOC). Organic carbon in plant biomass and SOC together represent total ecosystem carbon (TEC) pool. We identified 10 true mangrove species with DBH ranging from 6.0 to 13.5 cm. The site showed high plant density (18911 no. ha-1) with high diversity (H’=2.03). TEC pool of the site was 209.30 ± 45.40 MgC ha-1. The aboveground, belowground and SOC of the mangroves were (mean ± SD) 33.64 ± 1.05 MgC ha-1, 13.12 ± 0.41 MgC ha-1, and 162.50 ± 45.20 MgC ha-1. SOC accounted for nearly 78% of the TEC stock. There was gradual increment in SOC stock with increasing depth. If disturbed the site can emit an average of 768.10 ± 67.90 Mg CO2 ha-1. The site is highly vulnerable to tourism development and urbanization, yet carries relatively higher amounts of carbon in their sediments. This demands for an enhanced awareness and scientific understanding for developing strategies for conservation and restoration of blue carbon pool of this mangrove ecosystem
In vitro antioxidant, anti-inflammatory and anti-cancer activities of plant extracts used in Ayurvedic medicine
(Faculty of Science, University of Kelaniya, Sri Lanka, 2021) Munasinghe, C. C. J.; Hapugaswatta, H.; Seneviratne, K. N.; Jayathilaka, N.
Traditional medicine may provide leads for potential new therapeutics. Sri Lanka is home to numerous plant species with reported anti-cancer properties according to traditional medical practices. Further, polyphenolic compounds extracted from various plant products have been reported to exhibit antioxidant, anti-inflammatory and anticancer activity. In this study we assessed the antioxidant, anti-inflammatory and anti-cancer potential against acute myelogenous leukemia (AML) in several ayurvedic plant species; Nigella sativa (Kaluduru) seeds, Hemidesmus indicus (Iramusu) roots, Adenanthera pavonina (Madatiya) seeds and Murraya koenigii (Curry leaves). These plant species have already reported of possessing anti-cancer activity against different cancer types. The main objective of this study is to determine the anti-cancer activity of theses plant extracts against AML. All the plant parts were thoroughly cleaned, dried, grounded into fine powder and bioactive compounds were fractionated into different solvents. The Total phenolic content (TPC), antioxidant activity, anti-inflammatory activity and cytotoxicity against AML were evaluated using Folin-Ciocalteu assay, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay, Ferric reducing power antioxidant assay, protein denaturation inhibition assay and Cell TiterGo viability assay using THP-1 cells as a model for AML. N. sativa (kaluduru) aqueous extract showed the highest TPC; 3.14 ± 0.01 mg GAE/g dry weight (after tannin removal) and 2.92 ± 0.01 mg GAE/g dry weight (after protein removal), H. indicus (iramusu) aqueous extract recorded the highest DPPH radical scavenging activity and ferric reducing power and N. sativa (aqueous extract), A. pavonina (madatiya) ethanol extract and M. koenigii (curry leaves) methanol extract showed significantly high values (p<0.05) for the anti-inflammatory activity compared to other tested extracts. H. indicus (aqueous extract) showed the highest cytotoxicity against THP-1 cells with the lowest IC50 value (0.37 ± 0.01 mg/mL). All the tested extracts showed more than 50% inhibition of THP-1 cells at the highest tested concentration (15 mg/mL). All the tested plant extracts showed presence of polyphenols with antioxidant, anti-inflammatory and cytotoxic properties. However, the TPC as determined by Folin Ciocalteu assay does not explain the resulting cytotoxicity against AML cells. Further studies are needed to assess whether the observed anti-leukemic activity is due to cytotoxicity that would affect healthy cells and to assess whether the observed activities are specific against AML.
Luminescent studies of europium (III) fluorobenzoic acid derivatives: Correlating the calculated electronic energies and the experimental luminescent efficiencies through computational studies
(Faculty of Science, University of Kelaniya, Sri Lanka, 2021) Silva, C. R. De; Fratarcangeli, M.
Europium (III)-based luminescent complexes promise extensive potential applications in immunoassay technology, high throughput drug screening, organic light emitting diodes (OLEDs), and biomedical imaging. Europium-ligand complexes present unique properties such as monochromatic emission at 614 nm, long luminescent lifetimes enabling time-resolved measurements, minimal photobleaching, and large Stokes shifts. Ligand design for enhancing the quantum efficiency of europium complexes is currently active. For this reason, it is important to understand the electronic mechanisms that allow europium-metal complexes to fluoresce. Here, we report the structural and spectroscopic properties of a series of europium (III) complexes containing fluorobenzoic acid derivatives using density functional theory calculations. Calculations were carried out using the B3LYP method and 6-31G* and 6-311+G** basis sets. Upon increasing the ligand fluorination, the absorption maximum wavelength shows a blue shift. Excited state energy gaps of the complexes were found to be sensitive to the identity and the position of the ligand substituents. A nitro substitution results in a decrement of the vertical excited states, significantly reducing the luminescent quantum yield. The inter-system crossing energy gap is strongly regulated by the position of the ligand substituent. It is significantly reduced by having substituents closer to the metal coordination site. The optimum energy gaps resulting in enhanced luminescent quantum yields were identified. The correlation among the calculated experimental luminescent quantum yields and the calculated electronic energy levels will be discussed to provide insight into designing highly luminescent europium complexes.
Tea waste derived activated carbon – polyacrylamide composites as a potential agent for the removal of Calcium and Magnesium based water hardness
(Faculty of Science, University of Kelaniya, Sri Lanka, 2021) Undugoda, P. M.; Mathota Arachchige, Y. L. N.
Water hardness is caused by dissolved minerals, mostly by Calcium and Magnesium. Hardness in natural water can interfere with day-to-day household activities like laundry, washing, bathing, and personal beauty services. Clothes washed in hard water may look dull and rough. Long-term consumption of hard water can cause kidney dysfunction, which may lead to other diseases such as cerebrovascular disease, diabetes, and others. In this study, Polyacrylamide (PAM) and activated carbon derived from tea waste have been used to prepare a novel adsorbent material at temperature 55 °C, where the prepared polyacrylamide-activated carbon (PAC) composite was used as an alternative and low-cost adsorbent for reduction of Calcium and Magnesium from hard water. Batch experiments were done for both Calcium and Magnesium solutions to find out the influences of different conditions such as adsorbent dosage, initial pH of the solution, temperature, initial concentration, and contact time on the adsorption of each metal. The residual concentrations of Calcium and Magnesium were determined by Atomic Absorption Spectroscopy (AAS). A maximum reduction percentage of 98% was obtained for both Calcium and Magnesium at optimized conditions namely, adsorbent dosage 0.5 g, initial pH 7, temperature 25 °C, initial concentrations of Calcium 71 mg/L, and Magnesium 51 mg/L and contact time 120 minutes. Adsorption processes were analyzed using Langmuir and Freundlich isotherm models, and it has been shown that the adsorption of Calcium was best fitted to the Langmuir model where the adsorbate molecules have equal adsorption energies on the surface. The adsorption of Magnesium was best fitted to the Freundlich model which describes different adsorption energies. The adsorption kinetic studies revealed that the adsorption of Calcium and Magnesium onto the prepared PAC composite is best fitted to the pseudo-first-order kinetic model which assumes the rate of change of solute uptake is proportional to the difference in saturation concentration. Thermodynamic results showed that both adsorption processes were feasible and spontaneous under adsorption conditions. Further, the prepared PAC composite had a greater reduction percentage for Calcium and Magnesium than pure polyacrylamide gel or activated carbon. For both metals, the PAC composite showed a 98% reduction percentage while pure polyacrylamide gel and activated carbon showed only 16% and 75% reduction percentages, respectively. Therefore, prepared PAC composite can be used as a potential adsorbent in removing Calcium and Magnesium from aqueous media.
An image processing approach to detect the quality of cinnamon sticks
(Faculty of Science, University of Kelaniya, Sri Lanka, 2021) Sandamali, H. A. C.; Liyanage, C. R.
Cinnamon is one of the most important and valuable spices in Sri Lanka. Sri Lanka ranks first in world cinnamon production and has a long-standing reputation in the international market due to its unique quality, colour, flavour, and aroma. While Sri Lanka is a world market leader, meeting quality standards is a major issue Sri Lankan cinnamon exporters face. There are several types of cinnamon grades and different prices for each grade. The selling price of cinnamon will be determined by the most available type of grade in a cinnamon bale. However, in real practice, the quality grades of cinnamon bales are determined through collectors’ experience and knowledge, and there is no automated system to accurately identify the quality of cinnamon. Therefore, in some situations, disadvantages arise for the farmers when the majority of sticks in a bale are from a lower grade, where they will not get a suitable price for the higher grade portion. To address these issues, this study presents an image processing method to automatically detect the quality grades of cinnamon quills without any expert knowledge. Mainly, the quality of cinnamon quills will be measured based on the diameter, ash percentage, length, and colour. The current study has developed a model by considering all these four factors. As there are slight differences between each grade, a highly precise solution is needed to detect the grades accurately. Therefore, especially the image collection and pre-processing were done with extra caution. During the phases; calculating the diameter, finding the percentage of patches, and calculating the length, the accuracy of the results were evaluated based on a reference issued by the department of export agriculture, Sri Lanka. This reference contains the standardized values of maximum diameter, maximum patch percentage, minimum length, and the number of sticks per kilogram according to each cinnamon grade. Moreover, the accuracy of the measurement of colour was evaluated against a reference(DSLS 81) supplied by the Sri Lankan Standards Institute. The individual accuracies of each stage were 73, 85, 80, and 68 percent in measuring the diameter, colour, length, and patch percentage, respectively, and the accuracy of the final result was around 65 percent. In conclusion, this model will help to identify the quality of cinnamon quills accurately and efficiently compared to manual measurements.
Investigation of the effect of source temperature on close-spaced sublimated CdTe thin films
(Faculty of Science, University of Kelaniya, Sri Lanka, 2021) Lakmal, A. A. I.; Kumarasinghe, R. K. K. G. R. G.; Seneviratne, V. A.; Dassanayake, B. S.
Cadmium telluride (CdTe) is one of the most promising II-VI group semiconductors used to fabricate heterojunction thin-film solar cells. Close-spaced sublimation is one of the best techniques for the deposition of polycrystalline CdTe thin films. In this study, CdTe thin films were deposited on the cleaned FTO glass substrates using the close-spaced sublimation technique by varying the source temperature from 560 °C to 720 °C in steps of 20 °C. The temperature of the substrates, source to substrate separation, and deposition duration were maintained at 540 °C, 4 mm, and 5 minutes respectively. Ar(g) was introduced to the vacuum chamber, keeping the pressure at 7.9 Torr. The deposition was carried out using high purity CdTe powder placed in a graphite crucible. An almost transparent thin CdTe layer was observed at the source temperature of 560 °C. In comparison, a slightly decomposed layer was seen when the source temperature was 720 °C, which could be considered two boundary points in the temperature range selected. The CdTe layer deposited at source temperature 580 °C had a better thickness compared to 560 °C and pinholes could be visible to the naked eye. The average transmittance beyond the absorption edge was decreased with the increment of source temperature. The optical bandgaps of all samples were in the range of 1.48 - 1.50 eV. The crystallinity of the deposited thin films was shown an increasing trend with the increment of source temperature. According to the SEM analysis, the increment of source temperature has led to better grain enhancement. Based on the above characterizations, the optimum source temperature was determined as 660 °C. To further confirm this result, CdS/CdTe full cells were fabricated by depositing the above CdTe layers on thermally evaporated CdS films with back contacts in the order of Cu before Au. Among the CdS/CdTe/Cu/Au cells fabricated for electrical characterization, the highest efficiency was obtained for the source temperature of 660 °C.
Development of a liquid fertilizer system from bio-slurry waste and natural resources: A case study on early growth of chili (Capsicum annum L.)
(Faculty of Science, University of Kelaniya, Sri Lanka., 2021) Ranaweera, A.D. P. S.; Karunawardana, W. A. L. S.; Abeysinghe, D. T.; Premaratne, W. A. P. J.
Hydroponics or soil-less culture is a technology for growing plants in nutrient solutions that supply elements needed for optimum plant growth with or without use of an inert medium to provide mechanical support. Hydroponics offer opportunities to provide optimal conditions for plant growth and therefore, higher yields can be obtained as compared to open field agriculture. Here we aim to develop a liquid fertilizer system using a bio-slurry waste obtained from biogas reactor, selected animal waste, wood ash and dolomite. Five liquid biofertilizer systems (M1, M2, M3, M4 and M5) were developed by mixing different ratios of bio-slurry waste obtained from biogas reactor, cow dung, poultry waste, wood ash and dolomite. A control experiment was carried out with Albert solution, a commercial chemical liquid fertilizer. The liquid fertilizer systems were tested using 12 Chili (Capsicum annum L.) plants in each treatment and treated with a continuous hydroponic cultivation system for 12 weeks in triplicate. The pH in hydroponic systems varied from 6 to 8. At the end of the 12 weeks’ plant growth was monitored by measuring the height of the plant. Chili plants grown in fertilizer mixture M4 (bio slurry waste: 36.0 L, cow dung: 600.0 g, poultry waste: 600.0 g, wood ash: 75.0 g, dolomite: 75.0 g) gave the highest growth rate (50.3±3.0 cm) and the highest harvest (28.8±1.2 g) among the five developed biofertilizer systems. This M4 fertilizer system has the highest N (49.0±0.2 ppm), P (9.9±0.1 ppm) and K (434.2±0.8 ppm) content. Fertilizer system M1 which has only bio-slurry waste showed the lowest growth rate (37.4±1.6 cm) and the lowest harvest (16.1±0.6 g). M1 has the lowest nutrients content (N: 28.3±0.1 ppm, K: 349.0±0.7 ppm, P: 4.5±0.1 ppm) among the five liquid fertilizers. The control, Albert solution which has N (10.6%), K (16.3%) and P (9.3%) showed a growth rate of 46.0±5.4 cm and a harvest of 30.1±1.6 g. Therefore, it can be concluded that added natural ingredients improve the effectiveness and quality of the liquid fertilizer with high content of nutrients. Therefore, M4 liquid fertilizer system has the potential to be developed as an economical, effective, eco-friendly fertilizer system for the hydroponic cultivation of chili plants compared to commercial chemical liquid fertilizers.
Correlation between pest gastropod occurrence and selected environmental variables in agricultural lands in the Nuwara Eliya district, Sri Lanka
(Faculty of Science, University of Kelaniya, Sri Lanka., 2021) Thilakarathne, K.G. D. D.; Ranawana, K. B.; Kumburegama, S.
Many of the exotic terrestrial pest gastropods introduced to Sri Lanka, either intentionally or accidentally, are well established as pests in agricultural lands, but hardly any studies have been carried out to determine the factors affecting their occurrence. Hence, this study was conducted to determine the correlation between selected environmental factors and density of gastropod pest species in some agricultural lands in the Nuwara Eliya district. A total of 80 agricultural lands were sampled from 2017 to 2019, where each land was surveyed for pest gastropods by establishing ten 1 m2 sampling plots for a maximum of 15 minutes/plot. Species richness and abundance were recorded in the field and species were identified at the field using available guides. Unidentified species were brought to the laboratory for further identification. Elevation, atmospheric temperature, rainfall, relative humidity and soil pH were measured using a Magellan Explorist 310 portable GPS, a Kestrel 4000nv weather tracker and a HANNA-HI-99121 electronic digital pH meter at each sampling location. Canonical correspondence analysis (CCA), Pearson’s correlation and generalized linear mixed model (GLMM) in R studio were used to analyze data. The first two axis of CCA explained 85% of the total variation. Species were ordered along the first axis in the CCA primarily affected by elevation while the second axis affected by rainfall and soil pH. CCA results indicated that the measured environmental factors influencing the occurrence of the gastropod species. For example, Deroceras laeve (Muller, 1774), Deroceras reticulatum (Miller, 1774), Milax gagates (Draparnaaud, 1801) and Mariella dussumieri (Gray, 1856) were influenced by the elevation and atmospheric temperature; Cryptozona chenui (Pfeiffer, 1847), Macrochlamys indica (Godwin and Austen, 1883), Subulina octona (Bruguiere, 1789) and Euplecta emiliana (Pfeiffer, 1854) were influenced by the rainfall and soil pH; while Allopeas gracile (Hutton, 1834), Leavicaulis alte (Ferussac, 1822), Lissachatina fulica (Bowdich, 1822), Cryptozona bistrialis (Beck, 1837) and Ratnadvipia irradians (Pfeiffer, 1853) were influenced by the relative humidity. According to the correlation analysis, the gastropod species richness was positively correlated to the daily rainfall (r=0.34, p<0.05); the total species abundance at all the sites were positively correlated to the elevation (r=0.56, p<0.05) and negatively correlated to the atmospheric temperature (r=-0.42, p<0.05). The results of this study indicate that gastropods could become invasive and pests due to changes in climatic and environmental factors whilst causing severe economic losses to agricultural crops in the Nuwara Eliya district. Therefore, the knowledge on the effects of environmental factors, as revealed by the results of this study, can be used to formulate management plans to control the occurrence and distribution of pest gastropods in the Nuwara Eliya district.