IRSPAS 2019

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Assessing the substrate degradation specificity and life stage performances of black solider fly larvae (Hermetia illucens) in different bio-degradable waste substrates
(4th International Research Symposium on Pure and Applied Sciences, Faculty of Science, University of Kelaniya, Sri Lanka, 2019) Magamage, M. P. S.; Ellawidana, D. M.; Perera, R. N. N.; Lakmini, P. K.; Priyadarshana, M. K. C.
Solid waste management has become decisive challenge in Sri Lanka where majority of the generated waste is dumped in an unsystematic way. It is highly encouraged to pursuit more reliable waste management methods in an effective way to mitigate this issue. The black solider fly (Diptera: Hermetia illucens) is a harmless insect proven for its larvae’s enormous bio-waste degradable ability and animal feed. This study intends to propose the most suitable substrate to breed the larvae by assessing substrate effect for the larval growth performance and substrate degradable specificity. Specially designed bin which facilitate brooding, aeration, leachate extraction and self-harvesting was used. As three different substrates, 100% swill (T1), 100% fish offal (T2) and rotten fruits and vegetables (T3) were used and maximum allowable height of 20 cm was marked inside the bin. Egg laying lap, eggs volume and length of egg masses, substrate consumption height, pH, average moisture % (wet/dry basis), temperature (inside /outside the substrate), length and width of different larval stages and larval proximate value (crude protein %) were recorded. During the egg laying and colonization period each bin was examined in two hours interval from 8.00 a.m. to 5.00 p.m. for two months. Once brooding initiated, new substrate was refilled by 1 kg in two day intervals. First eggs emergence sequence was recorded as T1, T2 then T3. There was no substrate dependent effect for the mean egg volume (0.97 eggs/mm3) and average egg length (895.389μm) in each bin using three replicates. The highest substrate consumption height was recorded in T1 (10.3 cm). Highest pH drop of the decaying substrates was recorded in T1 (5.82) where T2 (6.17) recorded the least pH drop of the substrate. On wet / dry basis, the highest moisture content was in T3 (20.04% and 25.06% respectively) whereas the lowest moisture level was in T2 (12.06% and13.71% respectively). The highest inner (37.1°C) and outer (30.9°C) substrate temperature was recorded in T1 and lowest value was recorded in T3. According to the larval growth performances, larval width and length were varying with respect to the larval stage. Larval crude protein % was highest in T3 (48.95%) and lowest in T1(33.06%). In conclusion, based on the mean comparison study 100% swill indicated the most favorable conditions for the larval growth whereas larvae grew in rotten fruits and vegetables were the most suitable substitute for animal feed as a protein source.
Release of curcumin from chickpea protein submicron particles at gastrointestinal pH values
(4th International Research Symposium on Pure and Applied Sciences, Faculty of Science, University of Kelaniya, Sri Lanka, 2019) Shakoor, I. F.; Pamunuwa, G.; Karunaratne, D. N.
Activity of bioactive components such as curcumin, which is a natural polyphenolic compound, depends on their stability, solubility, absorption and bioavailability at specific sites. Development of natural polymer based oral delivery systems for controlled delivery of bioactives has become essential in order to improve the aforementioned characteristics of those compounds. Among the biopolymers used in the formation of delivery vehicles, protein holds a prominent place due to its high biocompatibility and biodegradability. Chickpea (Cicer arietinum L.) protein shows high protein bioavailability and it has been used successfully in drug encapsulation processes. Therefore, the purpose of the study was to develop curcumin-loaded submicron particles using chickpea protein, and to characterize, and to evaluate the release of curcumin via understanding its release kinetics from the protein matrix. To prepare chickpea protein isolates, alkaline extraction and subsequent precipitation of the proteins at the isoelectric point (4.5) was followed. Glyoxal was used as a cross-linker. In vitro release studies were carried out using the dialysis bag method, using UV-visible spectroscopy for quantification, at simulated gastric and intestinal pH buffers without enzymes. The release profiles were fitted in to eight different mathematical models namely Zero order, First order, Higuchi, Hixon-Crowell, Korsemeyer-Peppas, Baker-Lonsdale, Weibull and Gompertz, to determine and interpret the kinetics of the drug release from the protein matrix. Encapsulation efficiency showed a high value of 89 % and loading capacity approximated to 0.45 %. Average particle size, polydispersity index and zeta potential were found to be 466.9 nm, 290.5 % and -10.8 mV, respectively. Release of curcumin from the protein matrix showed a slower controlled release compared to the release of free curcumin at both pHs. Release of encapsulated curcumin at pH 2 showed a much higher release compared to the release at pH 6.8. In fact, maximum release at pH 2 and pH 6.8 were approximately 26 % and 16 % at the sixth hour, respectively. Release profiles of curcumin encapsulated protein fitted well with Higuchi and Weibull models at pH 2 and 6.8, respectively. At pH 6.8, release followed a Weibull sigmoidal pattern showing an asymptotic maximal release. At pH 2, release of encapsulated curcumin followed a diffusional release from the matrix. This study indicates differential release behaviour of curcumin from chickpea delivery vehicles at gastric and intestinal pH conditions
Determination of antimicrobial efficacy of some commercially available therapeutic mouthwashes
(4th International Research Symposium on Pure and Applied Sciences, Faculty of Science, University of Kelaniya, Sri Lanka, 2019) Rathnayake, R. M. S. U.; Jayaratne, D. L.
Mouthwashes are medically formulated liquids, which are held in the mouth and swished by the action of perioral musculature to eliminate oral pathogens. Many mouthwashes are often used by people as they are prescribed by the dentistry, in order to prevent several oral conditions and to treat them. Many of the commercially available mouthwashes are claiming to have antimicrobial properties. This in vitro study, mainly aims to determine the different levels of antimicrobial efficacies in some commercially available therapeutic mouthwashes. The study included four commercially available mouthwashes and they were named as Mouthwash 1, 2, 3 and 4. A newly formulated Ayurvedic mouthwash was also included. The antimicrobial efficacies of these mouthwashes were tested against five selected microorganisms; namely, Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 25923, Pseudomonas aeruginosa ATCC 27853, Streptococcus pyogenes and Candida albicans. Many of the microorganisms used in the test are significant in dentistry for causing several oral problems. Original concentration of the mouthwashes used in the study was decided as per the medical directions given for each mouthwash. Agar well-diffusion method and agar disc-diffusion method were used to determine the antimicrobial efficacy levels of the mouthwashes. Each experiment was replicated thrice. Validation test was carried out to confirm that the analytical procedure employed in the test is suitable for its intended use, which ensured there is no effect of penetrability of the substances in agar that may affect the results. The diameter of the inhibition zones obtained from the agar well diffusion and disc-diffusion methods were measured in each case and the obtained results were statistically compared using the Tukey’s method. The results obtained from the Tukey’s method indicated that the highest antimicrobial effectiveness was shown by mouthwash 1 against C. albicans in both disc diffusion and well diffusion methods showing an average inhibition zone diameter of 20.67 cm in both methods. The second highest antimicrobial effectiveness was shown by the mouthwash 1 against S. pyogenes and the third highest antimicrobial effectiveness was also shown by the mouthwash 1 against E. coli. The active antimicrobial component contained in Mouthwash 1 was chlorohexidine gluconate. When comparing the two non-herbal mouthwashes, the least effectiveness was showed by the mouthwash 2 against P. aeruginosa. Mouthwash 2 contained chlorohexidine digluconate as the active antimicrobial ingredient. The herbal and Ayurvedic mouthwashes did not show any antimicrobial properties in the particular tests.
Differential transform method for an immunology model of HIV
(4th International Research Symposium on Pure and Applied Sciences, Faculty of Science, University of Kelaniya, Sri Lanka, 2019) Silva, M. B. G. M. K.; Peiris, C. M. B. I. N.; Wimaladharma, N. A. S. N.
Human Immunodeficiency Virus (HIV) mainly attacks a person’s immune system. The virus destroys 𝐶𝐷4+𝑇 cells, which mainly fight against the infection. As a result, the probability of facing the risk of various deadly infections increases and sometimes it leads to a cancer due to the weakening of the immune system. The main objective of the research is to solve a system of ordinary differential equations for a dynamic model of HIV using semi numerical analytical method, namely differential transform method (DTM). The solutions, which were obtained from DTM were compared with the solutions of modified Euler method and forth order Runge Kutta (RK4) method. Moreover, Pade approximation was applied for DTM. Pade approximated solutions were obtained by using a limited number of coefficients of solutions of power series given by DTM. The results of the research show that DTM is an efficient method to solve systems of nonlinear ordinary differential equation such as dynamic model of HIV. The solutions well behaved for small time intervals. Hence, the Pade approximation was applied with DTM in order to obtain accurate solutions for large time intervals.
Developing a scale to assess the Spiralling Whitefly, Aleurodicus disperses Russel (Hemiptera: Aleyrodidae), infestation on cassava (Manihot esculenta)
(4th International Research Symposium on Pure and Applied Sciences, Faculty of Science, University of Kelaniya, Sri Lanka, 2019) Gunawardana, D. U. M.; Warnasooriya, P. G. A. S.; Hemachandra, K. S.
Spiralling whitefly, Aleurodicus dispersus Russel (Aleyrodidae) is a highly polyphagous quarantine pest, spread in tropical and subtropical region of the world. As direct feeders of cell sap whiteflies affect adversely on growth and act as vectors of viruses and spread plant diseases, of many agricultural and non-agricultural plants. This pest can be managed by the means of biological control with the use of coccinellid predators. In this process, it is necessary to make samples and assess the whitefly infestations in relation to many laboratory and field studies. In order to facilitate the assessment of whitefly populations, a study was conducted to develop a scale to measure the whitefly infestation in cassava. Whitefly infected cassava leaves were collected from cassava fields in Dholuwa-Kandy for one cropping season. Leaflets of collected leaves were separated (leaflet length 14.29 ± 0.43 cm, width 3.53 ± 0.21 cm and leaf area 57.86 ± 6.34 cm2 ) (n= 80). Each leaflet was examined separately under the binocular light microscope (10x4) and each growth stages (eggs, instar 1, instar 2, instar 3 and instar 4) of the whitefly were counted based on the four whitefly infestation levels (25%, 50%, 75% and 100%). The variation of eggs appears to have a more or less linear relationship with the area of infestation, but not the other growth stages. When total number of eggs is considered, a significant linear relationship (r2 = 87.1%, F (1, 78) = 524 p < 0.001) with infestation level was found which can be expressed as y =2.58 x +8.33. When total number of instars is considered, a significant linear relationship (r2 = 95.1%, F (1, 78) = 1521 p < 0.001) with infestation level was found which can be expressed as y =3.332 x +2.275. Eggs represented 80%, out of the total number of counted individuals. Significant relationships were observed between the area of infestation and instar 1, instar 2 and instar 3 but not with instar 4. Having considered these relationships, number of whitefly stages or the egg numbers can be predicted by examining the area of the infestation of the leaf, in this case cassava. There is a possibility, this pattern may be true for other crops but exact relationship is needed to be established, with a separate study
The cross-cultural adaptation of Morisky Green Levine Medication Adherence Scale for use with diagnosed patients of Ischemic Heart Disease in Sri Lanka
(4th International Research Symposium on Pure and Applied Sciences, Faculty of Science, University of Kelaniya, Sri Lanka, 2019) Kumara, W. G. C.; De Zoysa, P.; Balasuriya, A.; Fernando, N. F. J.
Ischemic Heart Disease (IHD) has been classified as one of the major cardiovascular diseases in the world and it has become the main cause of death in Sri Lanka. Medication adherence is defined as the level to which the client's behaviour complies with the established endorsements from a health care professional. Poor medication adherence to IHD is related to increased re-hospitalization and mortality and continuous assessment of medication adherence is extremely important among these patients. Morisky Green Levine Medication Adherence Scale is a medication adherence tool comprised of four items with yes/no response which results in a score ranging from 0 to 4. The study aim was to translate Morisky Green Levine Medication Adherence Scale into Sinhala and cross-culturally adapt it to the Sri Lankan setting. Translation, back translation, and pretest were conducted prior to a Delphi process which assessed the content and consensual validity of the scale. The Delphi process included two consultant physicians, a cardiologist, a clinical psychologist, and a registered pharmacist. In consensual validity, each item was rated, on a scale of 0(total disagreement) to 9(total agreement) (i) if its conceptual meaning was retained after translation, (ii) if it was appropriate to be used with IHD patients, and (iii) if it was culturally relevant to Sri Lanka. For content validity, each item was rated on a scale of 0 to 9 (i) if each item was an appropriate indicator of its scale, and (ii) if the composite of items was adequate to measure medication adherence. The ratings received from stage one were listed and re-sent for a second round and the re-ratings were evaluated for the degree of consensus. Items for this Medication Adherence Scale’s Sinhala version were chosen based on the following criteria: (i) the item was reworded or removed if 70% or more of the re-ratings were in category 0–3. If reworded, the Delphi Process was repeated for that item, and (ii) the item was kept with no change if 70% or more of the re-ratings were in categories of 4–6 and 7–9. No items were removed from the original scale and some items were reworded according to suggestions made by the experts to retain the conceptual meaning when translated into Sinhala. The Sinhala version of the Morisky Green Levine Medication Adherence Scale can be used in research, medication adherence evaluations and IHD preventive programmes in Sri Lankan setting with confidence.
Optimizing the conditions for the production of extracellular amylases under solid state fermentation using groundnut shell as the substrate
(4th International Research Symposium on Pure and Applied Sciences, Faculty of Science, University of Kelaniya, Sri Lanka, 2019) Kumarage, C. A.,; Weerasooriya, M. K. B.
Amylases are a group of hydrolase enzymes, which hydrolyse starch molecules into simple sugars. Amylase can be extracted from molds, which are capable of producing high amounts of amylase. Aspergillus niger is used more frequently in the commercial production of α- Amylase. Groundnut shell is one main by-product of the groundnut processing factories. Solid state fermentation (SSF) is considered more useful in industries as the extraction procedures are cheaper. Optimization of various parameters and manipulation of media are one of the most important techniques used for the production of enzymes in large quantities to meet industrial demands. Specific objective of the research is to optimize the culture conditions for the A. niger niger under solid state fermentation using ground nut shell as the carbon source. Parameters used to optimize the Amylase production are the effect of mineral salt media, mixed culture inoculation of A. niger and S. cerevisiae, effect of surfactants Tween 80 and Tween 20, effect of different pH values ranging from pH 4.0 to 7.0 and effect of changing concentration of carbon source. From the results from samples with and without mineral salt media, clearly indicate that enzyme activity is high in the samples with mineral salt media 28.736 U/mL. The Amylase activity of the sample with mixed culture of A. niger and S. cerevisiae together, is 38.070 U/mL. The highest enzyme activity of 42.300 U/mL, was shown with Tween 80. Maximum Amylase activity 41.540 U/mL was found at pH 5.5. Carbon source concentration for SSF was measured as the mass per volume. Optimum carbon source for SSF for the maximum amylase activity 49.413 U/mL on 5th day was found to be 40% by mass per volume of mineral salt solution (8 g per 20 mL). Final analysis shows that the maximum activity of alpha amylase was recorded at day 4, pH 5.5, in the presence of Tween 80 and with the simultaneous inoculation of A. niger and S. cerevisiae for 2 g of carbon source. The net yield of optimized culture is 49.401 U/mL and non-optimized culture is 30.215 U/mL.
A simulation on performance improvement at a university cafeteria: a case study
(4th International Research Symposium on Pure and Applied Sciences, Faculty of Science, University of Kelaniya, Sri Lanka, 2019) Samarawickrama, I. D. W.; Naotunna, T. U.; Bhagya, I. W. A. T.; Herath, H. M. C. N. K.
Universities are the foremost service providers of education in Sri Lanka. It necessitates the fleetness in the service provision at the premises. University cafeterias take a prominent place in which time intensity is at the highest. Tight schedules and the higher demand during meal times have led to customer dissatisfaction and brand switching. University cafeteria for the study was the main cafeteria for the resident students. The cafeteria served several types of food and handled payments from a single counter. It has long waiting lines and less service efficiency especially during the rushed meal times. The objective of this study was to identify the necessary practices in improving the performance of the cafeteria. Primary data on the arrival times and the service times were collected during the rushed meal times in the cafeteria on weekdays. The data collection was carried on for two weeks. It was assumed that the customers arrived independently and randomly, customers were served in the First-In-First-Serve (FIFS) basis and no customer left without being served. Inter-arrival and service times were calculated from the data. From all customers visiting the cafeteria a sample of 100 were selected. It was fed to obtain the probability distributions from the Rockwell ARENA tool, Input Analyser. The existing process of the cafeteria was modelled on ARENA 14.5 version and the waiting time at the queue was identified to be 3.30 minutes. The modelled operations showed a 93.4 percent serving at the cafeteria per hour. The study developed two performance improvement models. They were to increase the service rate by two-fold and to introduce another counter for the system. The developmental models showed a decrement in the waiting times for the service rate increment but not the additional counter. Thus the service rate increment was accepted as the most appropriate alternative. Waiting time of the chosen alternative was 0.83 minutes and a reduction of 74.84 percent in the waiting times. The serving of the alternative would be 100 percent per hour. It also reduced the total time in the system from 4.81 to 1.32 minutes. The study recommended the performance improvement of the cafeteria by increasing the service rate at the counter. Further it was suggested to standardize the operations and separate the food serving and payment handling at the counter
Cyanobacteria and 2-Methylisoborneol: the influence of Nitrogen and Phosphorous
(4th International Research Symposium on Pure and Applied Sciences, Faculty of Science, University of Kelaniya, Sri Lanka, 2019) Ganegoda, S. S.; Chinthaka, S. D. M.; Manage, P.M.
2-Methylisoborneol (2-MIB) is a key compound, which causes taste and odour (T&O) issues in water. Despite of no recorded health hazards reported associated with 2-MIB, water consumers reject the water with 2-MIB due to its unpleasant musty (moldy) T&O. The aim of this study was to study the correlation between cyanobacteria abundance, 2-MIB levels coupled with Nitrogen and Phosphorous levels. 2-MIB contamination level in sixteen raw water bodies, which are being used for drinking in six districts (Anuradhapura, Pollonnaruwa, Ampara, Batticaloa, Trincomalee and Hambanthota) were analyzed using Gas Chromatography–Mass Spectrometry coupled with Solid-phase micro extraction. Enumeration and identification of cyanobacteria was carried out using standard microscopic methods. Anabaena, Microcystis, Oscillatoria, and Cylindrospermopsis species were identified as the most abundant cyanobacteria. 2-MIB levels ranged from 5.3 ± 0.94 to 139.4 ± 0.21 ppt throughout the dry season of the sampling period, where the highest level was recorded in Kondawatuwana tank (139.4 ± 0.21 ppt) and the lowest was detected in Ridiyagama tank (5.3 ± 0.94). At wet season, 2-MIB levels ranged from 4.4 ± 0.78 to 73.8 ± 0.65 ppt, where the highest level was recorded in Jayanthi tank (73.8 ± 0.65 ppt), while the lowest was detected in Ridiyagama tank (5.3 ± 0.39 ppt). Recorded 2- MIB level was greater in dry season compared to the wet season. Seventy five percent (75%) of the sampling locations exceeded the human threshold levels of 2-MIB (5 ppt). Questionnaire survey showed that more than 95% end water consumers rejected drinking water contaminated with 2-MIB. Further it was found that the total cyanobacterial cell density (T.C.D) was positively correlated with 2-MIB and total phosphorous levels (p<0.05). Moreover, cell densities of Oscillatoria, Anabaena and Cylindrospermopsis species showed significant positive correlations (p<0.05) with 2-MIB contamination levels along with Pearson Correlation Coefficients (P.C.C) of 0.788, 0.682 and 0.731. However, no significant correlation was observed between Microcystis sp. and 2-MIB. Further, 2-MIB showed significant positive correlation (p<0.05) with total phosphorous (P.C.C 0.876), electrical conductivity (EC) (P.C.C, 0.771), and pH (P.C.C, 0.825). Increment of pH value leading to alkalinity is a known optimum condition for cyanobacteria growth while the current study shows alkalinity is favorable for 2-MIB. No significant correlation was obtained between total nitrogen (Nitrate –N, Nitrite –N, Ammonia –N) and 2-MIB nor T.C.D and total nitrogen. Thus, the results of the study indicate there is a direct positive correlation between 2-MIB, cyanobacteria and total phosphorous.
Effect of substrate temperature variation on opto-electronic properties of thermally evaporated CdS thin films
(4th International Research Symposium on Pure and Applied Sciences, Faculty of Science, University of Kelaniya, Sri Lanka, 2019) Lakmal, A. A. I.; Kumarasinghe, R. K. K. G. R. G.; Maddumage, D. C.; Kumarage, W. G. C.; Munasinghe, M. A. H. M.; Seneviratne, V. A.; Dassanayake, B. S.
Cadmium sulfide (CdS) is a II-VI group semiconducting material which has been thoroughly investigated due to its superior optical and electrical properties that can be applicable in wide range of semiconductor devices including photonic devices. Due to its direct and wide bandgap (~ 2.42 eV), it is vastly used as the window layer in heterojunction thin film solar cells. Compared to other deposition methods such as electrodeposition, spray pyrolysis, chemical bath deposition; thermal evaporation is an attractive method of deposition due to its high deposition rate, low cost of operation, low material consumption, minimum number of impurities and straight-line propagation of vapors. In the present study, CdS thin films were deposited on cleaned FTO glass substrates using thermal evaporation technique at substrate temperatures ranging from 50 to 250 °C at a pressure of 2×10-5 torr. Deposition was carried out using CdS powder (Sigma-Aldrich, 99.995%) using an alumina boat. Deposited samples were then annealed at 300 °C for 30 minutes in vacuum (pressure of 3×10-5 torr). Structural, optical and electrical properties of annealed CdS thin films were studied by employing X-ray diffraction, UV-Vis spectrometry, I-V measurements and capacitance vs. voltage measurements. All the electrical characterizations were carried out using a photoelectrochemical cell of (CdS/0.1 M Na2S2O3/Pt). The XRD analysis shows all the grown films are preferably oriented in the direction of (002) of hexagonal CdS. The optical band gap values were found to increase with increasing substrate temperature from 50 to 175 °C. ISC and VOC values of (CdS/0.1 M Na2S2O3/Pt) cell were also found to increase up to the substrate temperature of 175 °C. The observed highest ISC and VOC values were 37.24 μA and 314.9 mV respectively. Results indicate that the CdS thin films deposited at the substrate temperature of 175 °C has yielded the best optical and electrical properties compared to the films grown at other substrate temperatures
Implications of Fall Armyworm epidemic in Sri Lanka: A case study in Rathnapura district
(4th International Research Symposium on Pure and Applied Sciences, Faculty of Science, University of Kelaniya, Sri Lanka, 2019) Perera, R. N. N.; Magamage, M. P. S.; Siriwardhana, C.
The first emergence of the Fall Armyworm (FAW; Spodoptera frugiperda) was reported in Sri Lanka during August 2018 and caused a substantial yield loss in maize cultivation especially in Uva, Eastern, North Central, North Western, Northern and Sabaragamuwa provinces. During the 2018/19 Maha season, over 50 percent of the entire maize cultivation has been infested by the pest. The objective of the study was to understand the magnitude of FAW infestation, social response and its implications in Rathnapura district in Sri Lanka. This was considered as mandatory in terms of easiness in accessibility to close supervision by the university as well as with the objective of preventing infestations reaching economically catastrophic levels. Simultaneously to the field inspection programme, a survey was conducted in January-March 2019 in 13 maize growing agriculture instructor (AI) areas in the Rathnapura district to evaluate the severity of FAW infestation with the collaboration of the Provincial Department of Agriculture, Sabaragamuwa Province. University academia, students, and field officers from Department of Agriculture were participated to the survey and all 13 divisions were covered for collecting pest incidence information. GIS data were recorded in each point of infestation together with related other information such as land extent, host plant characteristics and the type of cropping system which plays important role in forecasting the pest occurrence in the subsequent cropping season. Based on the field survey, there were no evidences reported that pest occurrence in other crops apart from maize. Moreover, even in mixed cropping systems with little number of maize plants, heavy infestation was recorded only in maize. Data analysis was done based on the primary land infestation records obtained from each AI range by using MS office Excel 2010. Amount of land extent use for maize cultivation in Rathnapura district was estimated as 292.65 ha, while 32.95ha were infected with the pest (11.3%). Kaltota, Embilipitiya, Ambawila and Thimbolketiya were the AI areas with highest infestation recorded in the Ratnapura District reporting 5%, 4.8%, 4.5% and 3.85 % infestations respectively. Throughout the study period, attention was made by the research team for minimizing livelihood damage by conducting interactive awareness programs, which were directed to proper identification and control further spread of the pest. Even though maize was cultivated comparatively lower land extent in Rathnapura, effective and organized disaster management response in Rathnapura was able to minimize the pest impact to 11.3% from total losses. Mobilization of the whole agriculture community has wider implications in effective controlling of FAW while preserve the farmer trust on agriculture policy in Sri Lanka.
Assessment of groundwater contamination with environmental toxicants in CKDu endemic area, Polonnaruwa, Sri Lanka
(4th International Research Symposium on Pure and Applied Sciences, Faculty of Science, University of Kelaniya, Sri Lanka, 2019) Perera, W. P. R. T.; Dayananda, M. D. N. R; Botheju, W. S. M.; Liyanage, J. A.
Chronic Kidney Disease unknown etiology (CKDu) is one of the major health impacts predominantly confined to people in North Central Province in Sri Lanka. The root courses for the disease prevalence have not found yet. Therefore, this investigation was carried out to determine the groundwater contamination with environmental toxicants: Cadmium (Cd), Chromium (Cr), Copper (Cu), Lead (Pb), Zinc (Zn), Arsenic (As), Iron (Fe), Calcium (Ca), Magnesium (Mg) Fluoride (F), Sodium (Na) and Aluminium (Al) in Dimbulagala Grama Niladhari Division (GND) in Polonnaruwa District, Sri Lanka. The study investigated the groundwater quality of Dimbulagala GND in dry zone of Sri Lanka to assess its suitability for drinking purposes. Only Ten working tube wells were found in the studied area and groundwater samples were collected from the tube wells. Basic physicochemical parameters (pH, temperature, conductivity and dissolved oxygen), (Hatch HQ14d) and fluoride content were determined (Orion Star- 2014) onsite. Environmental toxicant concentrations were determined using Inductive Coupled Plasma Mass Spectrometry (ICP–MS, Agilent 7800). Results were analyzed using SPSS statistical software. descriptive statistics were performed on the data set and the Pearson correlation was applied. According to the results obtained from the onsite investigations the mean values of pH, conductivity and fluoride content were 7.78 (+1.28), 520 us/cm (+148) and 1.20 mg/l (+0.32) respectively. The mean value of the fluoride content has exceeded the permissible limit (1.0 mg/L), (SLS 614-2013). It was highlighted that significant toxic heavy metals such as Lead (Pb), Cadmium (Cd), Chromium (Cr) and Arsenic (As) levels as well as other metals like Fe, Cu, Zn, Na, Al have not been exceeded than permissible limits (SLS 614-2013). Statistically evaluation process proved none of the positive correlation is reported between heavy metal concentrations and Fluoride content of the groundwater in the studied area. But a negative correlation was reported between Fluoride and Cr (p= -0.05) in the groundwater in the studied area. Ca and Mg concentrations ranged between 3.43 mg/l to 130.56 mg/L And 6.54 mg/L to 75.32 mg/L respectively. Although mean Ca (10.12 mg/L) and Mg (15.45mg/L) did not exceed the permissible levels (100 mg/L and 30 mg/L for Ca and Mg), 40% and 50% of individual samples for Ca and Mg levels exceeded the permissible levels respectively. There is an urgent need for establishing proper long term drinking water treatment method for the studied area because of long term exposure to heavy metals such as Cd, Pb, Cr, As, and high levels of Fluoride as well as other environmental toxicants can be harmful to people. These findings can be used as a benchmark of raw water quality in the design processes of treatment plants
Analysis of heavy metal levels in rice grown in CKDu effected Krambankulama in Medawachchiya, Sri Lanka
(4th International Research Symposium on Pure and Applied Sciences, Faculty of Science, University of Kelaniya, Sri Lanka, 2019) Dilrukshi, A. A. S.; Weerasooriya, M. K. B.
Chronic Kidney Disease of unknown etiology (CKDu) is a major health problem faced in agricultural areas in North Central Province, Sri Lanka. Among many different causative factors that suspects, heavy metal contamination of food is one of the major issues which can lead to the renal failures in human. Though number of studies have been reported on CKDu, exact causative factor still remains unknown. Since rice (Oryza sativa) is the staple diet in these areas, heavy metal content of rice grown in CKDu prone Karambankulama, Medawachchiya was aimed to investigate. Rice samples (n=45) were collected from 5 sites in Karambankulama and in Hettipola, Kuliyapitiya. From each site 9 samples were collected at random locations. For the comparison purpose, Hettipola was selected as negative control site. The rice samples were acid digested in a microwave digester and heavy metals were analyzed using Atomic Absorption Spectrophotometer. Cu, Cr, Pb were detected in flame mode whereas Cd was detected in furnace mode. According to the results obtained mean metal contents of rice samples were as follows. Cu- 0.864±0.090 mg/kg, Cr- 0.903±0.020 mg/kg, Pb- 0.144±0.010 mg/kg and Cd-0.089±0.003 mg/kg for the samples collected from Karambankulama and Cu- 0.804±0.050 mg/kg, Cr- 0.895±0.010 mg/kg , Pb- 0.133±0.001 mg/kg and Cd- 0.061±0.001 mg/kg for the samples from Kuliyapitiya. There were significant difference (p<0.05) of the mean levels of Cu, Pb and Cd in rice between Karambankulama and Hettipola while there was no significant difference (p>0.05) with respect to the mean levels of Cr. To assess the safety of dietary intake, weekly intake of Cu, Cr, Pb and Cd in rice samples were calculated separately based on the daily consumption of rice and compared with the Provisional Tolerable Weekly Intake (PTWI) established by the WHO/FAO. The results indicated that weekly intake of Cr was higher for ages between 4-5 years and 14 years for both sites and that of Cd was higher for ages between 4-5 years in Karambankulama than the maximum weekly intake levels recommended by WHO/FAO. During the survey 12 CKDu patients were recorded in Karambankulama whereas none was recorded in Hettipola. Hence, Cd accumulation in the body over long period of time could be one of the causes for the present increase in chronic renal failure in the North Central province.
Investigation of spatial distribution of fluoride in drinking water sources in CKDu prevalence areas in Sri Lanka using GIS
(4th International Research Symposium on Pure and Applied Sciences, Faculty of Science, University of Kelaniya, Sri Lanka, 2019) Dayananda, M. D. N. R.; Botheju, W. S. M.; Perera, W. P. R. T.; Liyanage, J. A.
Chronic Kidney Disease of unknown etiology (CKDu) has identified as a significant health burden in rural dry zone areas in Sri Lanka. Fluoride is recognized as a nephrotoxic contaminant which deteriorates the renal functions progressively and the drinking water could be the major source which is responsible for the disease occurrence. Therefore, the present study attempted to investigate the spatial distribution of fluoride in drinking water sources in CKDu prevalence hotspots in Sri Lanka using Geographical Information System (GIS). Triplicated drinking water samples were collected from 30 sampling locations (from dug wells) in each Grama Niladhari Division (GND) including Wewelketiya GND in Anuradhapura district, Ambagaswewa GND in Polonnaruwa district, Naminigama GND in Mathale district and Buddhangala GND in Ampara district (Reference site) in dry season, Sri Lanka (February – March, 2019). Fluoride contents of collected samples were analyzed using ion chromatography (Metrom Eco_IC instrument). Spatial distribution patterns were interpolated using inverse distance weighted (IDW) and spatial autocorrelation (Moran’s Index- MI) tools in ArcMap 10.2.2 software. Results indicated that the mean fluoride levels of the collected water samples of Ambagaswewa and Wewalketiya areas were 1.37 ± 0.66 mg/L and 1.26 ± 0.65 mg/L respectively and those results exceeded the Sri Lankan drinking water standards (SLS 614: 2013) (1.0 mg/L) but the mean fluoride levels relevant to Naminigama area (0.82 ± 0.59 mg/L) complied with the SLS standards. Further 80% of the samples in Ambagaswewa GND and 95% of samples in Wewalketiya GND were highly contaminated with fluorides which were exceeded the SLS standard limits. Significantly higher Fluoride concentration levels were shown in Ambagaswewa GND (P= 0.103) and Wewalketiya GND (P= 0.704) compared to the reference area of the study.As well as fluoride concentration of the reference area was evenly distributed (MI= -0.005) in very low levels compared to the selected hot spots. Fluoride distribution were clustered with higher levels (MI = 0.31) in Wewalketiya GND, and Fluoride levels were evenly distributed with higher levels in Ambagaswewa GND and Naminigama GND with the Moran’s Indices of -0.12 and -0.07 respectively. It can be concluded that fluoride can be one of the risk factors affecting the prevalence of the CKDu. As the people are at a risk with the long-term exposure to the high fluoride concentrations, it is very essential to innovate a proper and affordable drinking water treatment technology for the affected areas and findings of this study can be used as background water quality data in the design process
General hygienic condition of packaged lettuce samples purchased from selected supermarkets in Gampaha district, Sri Lanka
(4th International Research Symposium on Pure and Applied Sciences, Faculty of Science, University of Kelaniya, Sri Lanka, 2019) Lokuwalpola, D. V.; Wanigasekara, D. N.; Sudesh, A. D. H.; Karunarathne, E. D. C.
Lettuce (Lactuca sativa) is usually consumed in raw form or processed minimally. Therefore, consumption of contaminated raw lettuce is associated with food outbreaks due to poor hygienic condition. Lettuce leaves can be contaminated with pathogenic microorganisms during harvesting, packaging and transportation processes. This study focuses on the general hygienic condition of the packaged lettuce available in supermarkets. Ten packaged samples were purchased from ten supermarkets of Gampaha district, Sri Lanka and they were labeled as L1, L2, L3, L4 and so on. 10 g of each lettuce sample was weighed and transferred to stomacher bags containing 90 mL of sterilized peptone water aseptically. After homogenization, a dilution series was prepared for each sample up to 10-6. One-milliliter aliquot of dilutions from 10-2 to 10-6 of each sample was plated using pour plate method. The used agar medium was Plate Count Agar. The inoculated agar plates were incubated at 30°C for 24 hours. Duplicates were used for all the plated dilutions of each sample. Average Colony Forming Units per gram (CFUg-1) was calculated. The calculated CFU/g values of L1 to L10 were 2.1×106, 1.8×106, 2.8×106, 2.3×105, 2.0×106, 1.2×105, 2.5×105, 1.9×104, 1.3×105 and 2.2×106 respectively. The highest obtained CFU per gram of lettuce was for L3. The lowest value was given by sample L8. Very high microbial load in packaged lettuce samples may indicate the poor hygienic condition
Over-expression of the multicopy-associated filamentation (maf) gene of Caldimonas manganoxidans MS1 and determination of the biological effect of MAF proteins on the viability of bacterial cells
(4th International Research Symposium on Pure and Applied Sciences, Faculty of Science, University of Kelaniya, Sri Lanka, 2019) Weerakkody, L. R.; Withrana, C.
Multicopy-Associated Filamentation (MAF) proteins represent a large family of conserved proteins. MAF protein is a nucleic acid binding, intra-cellular protein. The exact biochemical activity and functional mechanism of MAF protein remain unknown. However, it is believed that MAF protein has an inhibitory effect on septation, DNA and RNA synthesis and an intrinsic house cleaning function. Caldimonas manganoxidans is a Gram negative, thermophilic organism. The proteins produced by thermophilic microorganisms are known to have thermostable properties and high stability under extreme conditions, hence they can be considered as potential candidates for many industrial applications. The objective of this research was to clone the maf gene of C. manganoxidans MS1, express and determine the biological effect of recombinant MAF protein on cell viability of C. manganoxidans MS1, a native thermophilic organism previously isolated from Maha Oya hot water springs in Sri Lanka. The genomic DNA was extracted from the organism and the complete maf gene of C. manganoxidans MS1 was PCR amplified using gene specific primers, and initially cloned into pGEM®-T plasmid vector and transformed into the cloning host, Escherichia coli JM 109. Thereafter, the maf gene was cloned into the expression vector, pET 28a(+) plasmid and transformed into E. coli BL21 (DE3) pLysS expression host. Recombinant colonies were confirmed by colony PCR technique. The over-expressed MAF protein was purified from culture by using MagneHisTM protein Purification System. SDS-PAGE analysis indicated a molecular weight of around 22 kDa for the recombinant MAF protein and a concentration of approximately less than 0.2 μg/μL. Nucleotide BLAST (NCBI) of the complete nucleotide sequence obtained for C. manganoxidans MS1 maf gene from E.coli BL 21 (DE3) pLysS showed 99% identity with the complete sequence of maf gene (Accession: WP_026329982.1, GI: 648638231) of C. manganoxidans ATCC BAA-369 (Accession: NZ_KB905929.1, GI: 485071406). C. manganoxidans MS1 cells were exposed to the over-expressed, purified, recombinant MAF protein to determine the biological effect of MAF protein on cell viability. The bacterial cell viability was assessed by plate count method. Upon exposure to MAF protein, there was a remarkable decrease in CFU/mL with time, whereas there was a remarkable increase of CFU/mL with time when the bacterial cells were not exposed to MAF protein. In conclusion, maf gene from native C. manganoxidans MS1 strain was successfully cloned, expressed and MAF protein was purified from E.coli. The recombinant MAF protein has a negative effect on cell viability of C. manganoxidans MS1 strain, itself.
Comparison of the floral diversity at Beddagana and Diyasaru Urban Wetlands Parks, Colombo, Sri Lanka
(4th International Research Symposium on Pure and Applied Sciences, Faculty of Science, University of Kelaniya, Sri Lanka, 2019) Senevirathne, G. G. G. R. D.; Janaarthan, G.; Sivaseelan, M.; Rathnayake, H. M. C. L.; Gunawardena, M. P.
The district of Colombo is endowed with a variety of wetlands, mainly compromised of abandoned paddy fields, man-made lakes, and marshes. Since the 1980s, Colombo has lost almost 60% of its wetland area. Losing an average of 1.2% of its area per year, wetlands at present only make up 20 km2 of Colombo. Some of the main threats to wetlands and its plant diversity include anthropogenic activities and the rapid spreading of alien invasive species. A research was conducted to measure the diversity of plants in Beddagana Wetland Park and Diyasaru Wetland Park, in the Colombo Metropolitan area. The main objective of this study was to compare the floral diversity between the two urban wetland parks. The quadrat method was used for sampling (trees: 25 m2, saplings: 1 m2). Sampling was done at three habitats at each location; the first habitat being at the edge of the waterbody, the second being ten meters away from the waterbody and the third being twenty meters away from the waterbody. A single plot was placed in each habitat and three quadrats were placed in each plot. The 25 m2 quadrat was used to count plants taller than 1 meter and the 1 m2 quadrat was used to count plants shorter than 1 meter. The total number of individuals of each plant species inside each quadrat was recorded. A total of 13 species at Beddagana Wetland Park and 17 Species at Diyasaru Wetland Park were observed. The most common species observed at Beddagana Wetland Park was an alien invasive species; Annona glabra, with a relative abundance of 31.13%. The most common species observed at Diyasaru Wetland Park was Commelina diffusa, with a relative abundance of 29.77%. Simpson’s index and Shannon Diversity Index values were 0.8176/1.9668 for Beddagana Wetland Park and 0.7999/1.9310 for Diyasaru Wetland Park. The Shannon diversity values depict low species richness and species evenness in the area, which is a result of the raid of invasive floral species. Similarly, there is no key variance in the floral diversity at both sites. However, further studies and monitoring are recommended to determine the floral diversity at the Colombo wetlands. Furthermore, prompt bearable measures are needed to control the rapid spreading of invasive flora in the wetlands
Antimicrobial activity of dried fruit rind extract of Garcinia zeylanica
(4th International Research Symposium on Pure and Applied Sciences, Faculty of Science, University of Kelaniya, Sri Lanka, 2019) Sudesh, A. D. H.; Wanigasekara, D. N.; Karunarathne, E. D. C.
Emergence of antibiotic resistance among pathogenic microorganisms has become a severe threat in the medical field. Therefore, search for potential antimicrobial agents, such as substances from medicinal plants with alternative modes of action, is of major interest. Garcinia zeylanica, which is an endemic plant to Sri Lanka, is mainly used as a culinary herb. Antimicrobial activity of G. zeylanica dried fruit rind extract was evaluated against five bacterial strains and a yeast using Agar well-diffusion method. The study was aimed to investigate any potential antimicrobial effect of the fruit rind extract comparatively with conventional antibiotics. Commercially available dried rinds of G. zeylanica were collected and methanolic extract was prepared using Soxhlet method followed by solvent evaporation. Turbidity adjusted (McFarland 0.5), log phase cultures of Methicillin Resistant Staphylococcus aureus (MRSA), Methicillin Sensitive Staphylococcus aureus (MSSA), Escherichia coli (ATCC 25922), Staphylococcus pyogenes (ATCC 19615) and Pseudomonas aeruginosa (ATCC 27853) were evenly inoculated as a uniform lawn on Mueller Hinton Agar plates, while Candida albicans was swabbed to obtain an even lawn on Sabouraud Dextrose Agar . Three wells of 8 mm diameter per each plate were made for positive control, negative control and for the test extract. Amoxicillin was used as the positive control for MRSA, MSSA, E.coli and S. pyogenes and Ciprofloxacin was used so for P. aeruginosa. Fluconazole was the positive control for C. albicans. Sterile distilled water was used as the negative control. The test was triplicated for each strain. After 24 hour incubation at 37ºC, all the bacterial strains and the yeast were found to be susceptible to the dried rind extract of G. zeylanica. The mean inhibition zone diameters of the test extract for MRSA, MSSA, E.coli, S. pyogenes, P. aeruginosa and C. albicans were 29.33 mm, 28.67 mm, 20.67 mm, 31.00 mm, 24.00 mm and 25.67 mm respectively when the average inhibition zone diameters of the standard antibiotics were 11.67 mm, 39.33 mm, 29.67 mm, 37.67 mm, 38.67 mm and 27.67 mm accordingly. This study concludes that G. zeylanica dried fruit rind extract exerts a significant antimicrobial activity against the bacterial strains and the yeast strain tested
Stable forecasting of tax revenues of selected countries assisted by Clustering Approach
(4th International Research Symposium on Pure and Applied Sciences, Faculty of Science, University of Kelaniya, Sri Lanka, 2019) Karunarathne, A. W. S. P.; Liyanage, U. P.; Hewaarachchi, A. P.
Tax is one of the main income of a government that utilizes in public welfare and future investment. Taxation has goals: reducing the inequalities through a policy of redistribution of income, administrating the levels of inflation as well as deflation, protecting the local industries from foreign competitions through levies, and discouraging the undesirable activities such as consumption of tobacco. Additionally, taxation provides a major portion of Gross Domestic Product (GDP), depending on the country’s fiscal policy. Tax forecasting is essential towards strategizing government plans and future activities. However, tax revenue highly fluctuates due to many factors which include natural disasters, instability of political environment and government monitory policies. This study aims to find the set of best statistical forecasting models, by comparing the behavioral similarities of different tax revenues identified by clustering approach. Here, tax revenue data from 1972 to 2017 of 24 countries belonging to developing status: developed, developing and under-developed have been analyzed. Comparable and homogenize measure is obtained considering the tax revenue as a percentage of GDP. The countries with similar tax revenue are identified by using K-Means clustering. Consequently, the selected countries were clustered into five classes depending on their tax revenue as a percentage of GDP. The analysis shows that the tax revenue has similar behavior based on the similarities of countries’ developing status. Tax revenues data in each cluster were analyzed to identify the best fitted time series models. It has been found that models of the types Autoregressive Moving Average (ARMA) and Autoregressive (AR) are best fitted models for the representing tax revenue of the corresponding clusters. As an example, ARMA (2,2) model was fitted to one cluster and AR (1) model was fitted for another cluster of countries. According to the type of the model and their range of parameter values, it is found that similar models can be used to represent the tax revenue data within the underlying cluster. That is, there exist cluster specific models in the sense of model type and their parameter ranges. This finding can be utilized towards forecasting tax revenue in the case of the revenue data are highly affected with a qualitative factor, for example, political instability. In summary, through the clustering approach, stable forecasting of revenue data of a given country can be performed.
Effect of CaCO3 on mechanical properties and degradability of polythene manufactured from low density polyethylene
(4th International Research Symposium on Pure and Applied Sciences, Faculty of Science, University of Kelaniya, Sri Lanka, 2019) Abeywickrama, M. S. J .; Yatawara, M. D. M. D. W. M. M. K.
One of the major drawbacks of polythene manufactured from low density polyethylene is its poor degradability in the environment. The present study was therefore planned to assess how the addition of CaCO3 effect on the mechanical properties and on the degradability in ambient air, soil and in compost. Two types of polythene films, one with 100% polyethylene (P001) and another with 86% polyethylene + 14% CaCO3 (P002) were manufactured by a film extruder machine. The mechanical properties including thickness, tensile strength, elongation, moisture and water absorption of the two types of films were analyzed at the beginning of the experiment (n=10 for each test). Half of each film (n=144) was immersed in food waste contaminated water while the other half (n=144) was used as the control. One third of each of food waste contaminated film (n=28) was kept in ambient air while another one third was buried at 10 cm depth in soil. The remaining one third was buried in compost. The same procedure was carried out for control films. The percentage degradability was assessed after two and four months’ time intervals and the percentage degradability was calculated with respect to weight losses of films with time. A significant reduction of machine direction (MD) and transverse direction (TD) of both tensile strengths and elongations were shown by P002 (p< 0.05; student t-test). In addition, P001 showed 0.20% moisture content while P002 showed 0.01% moisture. Both films showed 0.03 mm initial thickness and P002 showed a significantly highest water absorption. The food waste contaminated P002 kept in ambient air showed 0.13% degradability while P001 showed 0.12% degradability after 4 months. Nevertheless, the food waste contaminated P002 showed 2.4% (non-contaminated- 2.1%) degradability while the food waste contaminated P001 showed 0.8% (non-contaminated- 0.6%) in soil. The food waste contaminated P002 showed 0.8% (non-contaminated- 0.7%) degradability while the food waste contaminated P001 showed 0.5% (non-contaminated- 0.3%) in compost. Nevertheless, transparency reduction and dark spots were also observed from food waste contaminated P002 buried in both soil and compost. The results further revealed that the films contaminated with foods (buried in both soil and compost) degraded more than those of the non-contaminated films but their percentage degradability were less than 2.5% by 04 months. The overall results conclude that CaCO3 was able to significantly reduce the mechanical properties; but unable to increase the degradability in the environment. Therefore, the present study implies that the addition of CaCO3 to polyethylene only makes the manufacture cost effective