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U n i v e r s i t y of P e r a d e n i y a

The Institutional Repository of the University of Peradeniya is the University's digital gateway to scholarly knowledge and research excellence. Established as the next phase of the Digital Library initiative launched by the University Library in 2011, it preserves, showcases, and provides open access to the intellectual output of the University community.

Through a rich collection of research articles, conference proceedings, theses, dissertations, and other scholarly works, the repository enhances the visibility, accessibility, and long-term preservation of knowledge, extending the global reach and impact of the University of Peradeniya’s academic and research contributions.

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Effective levels of compost for improvement of green leaf production of tea in mid country wet zone
(The University of Peradeniya, 2003-10-23) Premarathna, H. M. P. L.; Nandasena, K. A.; Basnayaka, B. F. A.
Higher productivity and profitability of Sri Lankan tea industry can only come from a combination of strategies; conservation of soil from degradation and restoration of soil fertility are some of the major strategies practiced in order to increase the tea production. Application of compost with the chemical fertilizer helps to improve the chemical, physical and biological properties of soil. This investigation was undertaken to study the effective levels of compost for improvement of green leaf production of tea in Mid Country Wet Zone. Compost produced from the Inclined Step Grade (lSG) system developed by the University of Peradeniya was used in eight treatment combinations. Three sites at the JEDB Estate, Hantana, were selected as three blocks, with two replicates. Treatment combinations were viz Tl-recomended chemical fertilizer only (I), T2-compost 2 t/ha + I, T3-compost 4 t/ha + I, T4-compost 6 t/ha + I, T5-compost Stlha + I, T6-compost 10 t/ha + I, T7-compost 12 t/ha + I, T8-compost only (70 t/ha). Supplementary nutrients were provided based on the recommendation except in T8. Green leaf yield was taken at weekly intervals and soil samplings were done at 3ʳᵈ 4ᵗʰ 6ᵗʰ and 8ᵗʰ weeks after compost application. Soil samples were analyzed for organic matter, total N, pH, available P, exchangeable K, Ca, Mg and biomass N. Results showed that, increment of rates of compost increased soil organic matter, total N, available P, exchangeable K, Ca and biomass N. Treatment effect on yield was not significantly different Yield response was not clearly showed as data was collected only for two months. At the end of two months T7 treatment-having 12 t/ha + I had higher amount of exchangeable K, Ca, Mg, biomass N than other treatments, except compost only treatment. From the results, use of 12t compost + chemical fertilizers appeared to be beneficial as an effective combination for tea in Mid Country Wet Zone. For better understanding of yield response, experiments should be carried out in long-term.
Retention of heavy metals by Eppawala rock phosphate ameliorated soils
(The University of Peradeniya, 2003-10-23) Marasinghe, M. A. T. D.; Indraratne, Srimathie P.
Contamination of the environment by heavy metals is a major concern because of their toxicity and threat to ,human life and the environment. Heavy metals contribute largely for the pollution of agricultural soils. This study was carried out to compare the retention of heavy metals by Eppawala Rock Phosphate (ERP) and an Alfisol as the soil, and to study the retention ability of heavy metals by different inorganic and organic fractions ofERP-ameliorated Alfisols. Adsorption studies were conducted for the Alfisol and ERP by equilibrating Zn,Cu and Cd in varying concentrations and calculating maximum adsorption capacity (M) using Langmuir equation. The ERP-ameliorated soil was prepared by mixing ERP with Alfisol at the rate of 5g/kg. This mixture was then contaminated with heavy metals by spiking Zn, Cu and Cd at the rate of 100, 100 and 2 mg/kg, respectively. Five extractions were conducted sequentially, to determine the fractionation of heavy metals into water soluble, exchangeable, carbonate bound, organic matter bound and Fe, Mn oxide bound forms. The M values of ERP for Zn, Cu and Cd were much higher than that for Alfisol. The fractionation study revealed that Zn was associated with the exchangeable, carbonate bound, organic matter bound and Fe, Mn oxide bound fractions in 70%, 1.5%, 4.~% and 5.1% respectively. Exchangeable Zn fraction was significantly higher than other Zn fractions (P<0.05). copper was found in all the above-mentioned five fractions. Exchangeable Cu fraction was significantly higher than the other Cu fractions (P< 0.05). Sorption of Cd into Fe and Mn oxides was 70%, and it was significantly higher (P<0.05) than other Cd fractions. Fractionation of Cd into water soluble and exchangeable was not detectable and carbonate bound and organic matter bound fractions were only 4% and 5% respectively. The ERP has higher retention ability of heavy metals than that of Alfisol. Therefore, ERP has the ability to ameliorate Zn, Cu and Cd-contaminated soils. In contaminated soils Zn is mostly associated with exchangeable fraction whereas Cu is in the exchangeable fraction and forms complexes with organic matter. The ERP-ameliorated soils converted Cd into non- available forms. The ERP-ameliorated soils could be effectively used to remediate the Cd contamination.
Antioxidant activity of some green tea constituents
(The University of Peradeniya, 2003-10-23) Kumar, N. S.; Rajapaksha, K. T. P. M. P.
Tea is unique in having a high concentration of flavanoids (catechins) that have been associated with the health benefits of tea. Catechins are polyphenolic compounds, and are known to be strong anti-oxidants that may help to protect the body from free radical damage. The results of recent scientific and medical studies suggest that tea drinking helps to reduce the risk of certain types of cancer and cardiovascular diseases. In the present study, the antioxidant activity of crude catechin extracts and green tea constituents obtained after fractionation by High Speed Countercurrent Chromatography (HSCCC) was determined using the β-carotene bleaching method and the DPPH (α,α- diphenyl-β-picrylhydrazyl) radical scavenging method using α-tocopherol (Vitamin E) and BRA (butylated hydroxyanisole) respectively, as reference compounds. Antioxidant activity of tea constituents was determined by a modified version of the β-carotene bleaching method, and was observed to decrease in the order, FLA2 (469.0) > FLAl (431.0) > epigallocatechin gallate EGCG (329.3) > epicatechin gallate ECG (280.0) > epigallocatechin EGC (201.0) > epicatechin gallate EC (151.0) > theobromine TB (74). Both BHA (680.0) and α-tocopherol (551.5) were stronger anti-oxidants than the tea constituents. In this method, the anti-oxidant coefficient of a sample is calculated. The difference in the anti-oxidant coefficients of the catechin samples with respect to a control sample is an indication of the inhibition of the coupled oxidation of linoleic acid and β-carotene by oxygen, and is measured by the absorption due to β-carotene at 470 nm. Antioxidant activity of tea constituents determined using the DPPH radical scavenging method decreased in the order ECG (90.8) > EGCG (90.0) > FLA2 (87.0) > FLAl (76.3) > EGC (58.9) > EC (36.8) > TB (35.3). In this method, the decrease in absorbance of the DPPH radical (DPPHo ) due to its reduction by different antioxidants was measured. According to this method, BRA showed less antioxidant activity than ECG, EGCG and a-tocopherol. Additionally, EGCG and ECG were found to be equally potent in hydrogen donating ability than BHA. Both methods confirm the strong anti-oxidant activity of green tea catechins. The unidentified catechins, FLAl and FLA2, are also potent anti-oxidants. Studies to establish the structures of these two compounds are in progress.
Effect of Oral Habits of Patients on the Overexpression of EGFR Protein in Oral Squamous Cell Carcinomas (OSCCS)
(University of Peradeniya, Sri Lanka, 2005-11-10) Dissanayake, U.; Amaratunga, E. A. P. D.; Dissanayake, D. M.
Over activation of a growth promoting proto-oncogene such as epidermal growth factor receptor (EGFR) plays a major role in the development of epithelial malignancies. It has been shown that alteration in the gene due to long term exposure to various carcinogenic agents is the reason for this. Betel chewing, smoking and consumption of alcohol are recognized risk factors for development of OSCCs. Both epidemiological and laboratory studies have revealed that the long-term exposure to such ingredients' which carry different carcinogenic agents results in malignant transformation, The aim of the present study was to observe the relationship between the frequency of different habits in patients with OSCCs and immuno-expression ofEGFR protein in their carcinomas. The sample consisted of 60 primary OSCC patients (males). Information on oral habits was recorded. Patients were stratified according to the severity of smoking, frequency of betel chewing and amount of alcohol consumption (mild = 1, moderate = 2, heavy = 3, habit free = 0). Over-expression of EGFR was assessed by immunohistochemistry using monoclonal antibody EGFR 113 (dil, 1:20, Novocastra). The percentage of positive cells, and the intensity (+, ++, +++) of expression were recorded. Analysis was done using chi square test. In the sample 86.6 % of the patients were betel chewers. Out of sixty, 62 % were smokers and 60 % consumed alcohol. EGFR positivity was 56 %. Over 50 % of the cancer cells were EGFR positive in 10/34 positive tumours. No significant difference was found in the over-expression of EGFR in 0SCCs, either between smokers I and non-smokers or between betel chewers and non-betel chewers. Intensity of EGFR expression in OSCCs was not significant both between smokers and non-smokers or chewers and non-chewers. There was a significant difference in the percentage of EGFR positive cells between heavy consumers of alcohol and mild to moderate consumers of alcohol «X2 = 19.4, P = 0.004). Intensity of EGFR protein expression also significantly differed between heavy consumers of alcohol and mild to moderate consumers of alcohol (X2 = 12.5, P = 0.05). No association was found between smoking, betel chewing and EGFR immunoreactivity in the present sample. However, exposure to alcohol showed a significant increase in the protein expression. Further studies are needed to confirm the over-expression of EGFR in oral squamous cell carcinomas induced by alcohol.
Oral-health-related knowledge, attitudes and oral-care practices of nursing undergraduates of Faculty of Allied Health Sciences, University of Peradeniya, Sri Lanka
(University of Peradeniya, Sri Lanka, 2021-11-11) Bandara, D. L.; Weerasinghe, G.K.; Pushpakumara, P.H.G.J.
As primary caregivers, it is important to establish adequate knowledge and a better attitude towards oral care in nursing officers. This study aimed to assess the oral health knowledge, attitude and oral-care practices among nursing undergraduates of the Faculty of Allied Health Sciences, University of Peradeniya, Sri Lanka. A cross-sectional analytical study was carried out in March 2019.Self-reported knowledge, attitude and oral-care practices of all students were assessed using a pre-tested self-administered questionnaire. Oral-health-related knowledge was evaluated under six sub scales. The majority of the participants were females, 109/148(73.65%). The highest mean score for knowledge was on dental plaque 7.16 (SD 4.5) while the lowest was on oral cancers, 3.89 (SD 3.13). However, nearly one-third of the undergraduates (37.84%) were not aware of the main purpose of tooth brushing. A positive attitude towards oral health was reported by 45 (30.41%, 95% CI 22.3-38.5%) undergraduates. Nevertheless, the distribution of the scores for the knowledge and attitude was not statistically different between gender and among different academic year of study.80% (n=118) of undergraduates brushed twice a day and 72% (n=107) used fluoridated toothpastes. Slightly more than half of the undergraduates (53.4%, 95% CI 44.6-62.2%) had snacks in between main meals while 41.9% (95% CI 33.3-50.6%) had maintained regular dental visits. Although a majority showed good oral practices, a significant percentage was not aware of the main purpose of tooth brushing. Similarly, the knowledge on oral cancer, which is a highly prevalent condition in Sri Lanka, was not satisfactory. No difference was found in scores of knowledge and attitude on oral health between genders or among academic year of study. Thus, suggest further studies and incorporation of properly designed oral health education programmes for the nursing undergraduates.