University of Peradeniya

About: University of Peradeniya is a education organization based out in Kandy, Sri Lanka. It is known for research contribution in the topics: Population & Poison control. The organization has 5970 authors who have published 7388 publications receiving 197002 citations.

Geochemical and petrological characteristics of Eppawala phosphate deposits, Sri Lanka

Abstract: The apatite-bearing carbonate rocks at Eppawala, Sri Lanka occur as massive, discontinuous bodies in a Precambrian, high-grade metamorphic terrain, which weather to form economically important phosphate deposits The ore bodies at Eppawala contain ≤42% P2O5, and citric acid solubility of different components varies from 4 to 6% The parent rocks are mainly made up of calcite, dolomite and apatite, with lesser amounts of ilmenite, magnetite, pyrite, forsterite, phlogopite, enstatite, magnesite, diopside, tremolite and spinel Most of minerals show an euhedral habit, with a wide range of crystal sizes (from a few millimetres to several decimetres) The Eppawala rocks are characterised by low silica (≤041%), high phosphorous (≤1058%) and high strontium content (2,960–6,819 ppm) Concentrations of light rare-earth elements in these rocks are comparably higher than those of marbles The REE fractionation of these rocks is pronounced, and La/Yb ratios vary between 14 and 43 Both apatite and calcite show markedly elevated strontium levels (≤06%) The δ 13CPDB and δ 18OSMOW values of the carbonates are in the range of –34 to –22 and 77 to 164‰ respectively The euhedral habit, as well as the presence of major quantities of apatite and considerable amounts of iron-bearing minerals suggest that the ore host rock has genetic links to an igneous source rather than to an intensely metamorphosed limestone The higher light REE contents of the rocks, compared to marbles, also argue against a metamorphic or sedimentary origin The Sr/Mn and Ce/La ratios in the apatite are ~40 and ~2 respectively, suggesting that they were formed in a carbonatite magma The markedly increased REE concentrations in the bulk chemistry of the rocks have been shown to be mainly controlled by the content of phosphate minerals Compared to most carbonatites, the Eppawala rocks are generally depleted in selected trace elements, particularly Ba, Nb, Th, V, U and Zr This depletion may be due to either a primary infertility of the parent magma with regard to such trace elements, or it is a result of fractional crystallisation during the rock formation The stable isotope ratios do not plot within the defined "mantle carbonatite box", but still lie within the broader range of carbonatitic rocks With these data at hand, it can be readily argued that the mode of occurrence, petrography and geochemistry of the Eppawala apatite-bearing carbonates provide conclusive evidence of their carbonatitic origin

Adsorption of crystal violet dye from aqueous solution onto chemically treated Artocarpus odoratissimus skin: equilibrium, thermodynamics, and kinetics studies

Abstract: In this study, the feasibility of utilizing Artocarpus odoratissimus skin (“Tarap” skin or TS) as a potential adsorbent for the removal of crystal violet dye was investigated. X-ray fluorescence, Fourier Transform Spectroscopic, and scanning electron microscopic investigation of TS and its NaOH-treated form (NaOH-TS) before and after interaction with crystal violet (CV) cationic dye indicate that the dye shows a strong affinity toward the adsorbent, which is enhanced upon the treatment with a NaOH solution. Decrease in the concentration of metal ions on the TS/NaOH-TS is indicative of the contribution of an ion-exchange mechanism owing to the positive charge of CV molecules. Comparison of experimental adsorption curves with calculated curves point the way toward the agreement with the Langmuir isotherm among the six models tested (Langmuir, Freundlich, Temkin, Dubinin–Radushkevich, Redlich–Peterson, and Sips) under optimized conditions with maximum adsorption capacity of 118 mg g−1 for TS which is...

Challenges in testing genetically modified crops for potential increases in endogenous allergen expression for safety

Abstract: Premarket, genetically modified (GM) plants are assessed for potential risks of food allergy. The major risk would be transfer of a gene encoding an allergen or protein nearly identical to an allergen into a different food source, which can be assessed by specific serum testing. The potential that a newly expressed protein might become an allergen is evaluated based on resistance to digestion in pepsin and abundance in food fractions. If the modified plant is a common allergenic source (e.g. soybean), regulatory guidelines suggest testing for increases in the expression of endogenous allergens. Some regulators request evaluating endogenous allergens for rarely allergenic plants (e.g. maize and rice). Since allergic individuals must avoid foods containing their allergen (e.g. peanut, soybean, maize, or rice), the relevance of the tests is unclear. Furthermore, no acceptance criteria are established and little is known about the natural variation in allergen concentrations in these crops. Our results demonstrate a 15-fold difference in the major maize allergen, lipid transfer protein between nine varieties, and complex variation in IgE binding to various soybean varieties. We question the value of evaluating endogenous allergens in GM plants unless the intent of the modification was production of a hypoallergenic crop.

Potential of Lichen Compounds as Antidiabetic Agents with Antioxidative Properties: A Review.

Abstract: The advancement in the knowledge of potent antioxidants has uncovered the way for greater insight in the treatment of diabetic complications. Lichens are a rich resource of novel bioactive compounds and their antioxidant potential is well documented. Herein we review the antidiabetic potential of lichens which have received considerable attention, in the recent past. We have correlated the antidiabetic and the antioxidant potential of lichen compounds. The study shows a good accordance between antioxidant and antidiabetic activity of lichens and points out the need to look into gathering the scarce and scattered data on biological activities for effective utilization. The review establishes that the lichen extracts, especially of Parmotrema sp. and Ramalina sp. have shown promising potential in both antidiabetic and antioxidant assays. Ubiquitous compounds, namely, zeorin, methylorsellinate, methyl-β-orcinol carboxylate, methyl haematommate, lecanoric acid, salazinic acid, sekikaic acid, usnic acid, gyrophoric acid, and lobaric acid have shown promising potential in both antidiabetic as well as antioxidant assays highlighting their potential for effective treatment of diabetic mellitus and its associated complications. The available compilation of this data provides the future perspectives and highlight the need for further studies of this potent herbal source to harvest more beneficial therapeutic antidiabetic drugs.

Value of peripheral blood count for dengue severity prediction.

Abstract: This retrospective study was conducted in 2017 with the objective of evaluating the value of acute phase peripheral blood parameters in predicting dengue haemorrhagic fever (DHF). Patients, who were admitted to Teaching Hospital Peradeniya between January and August 2017 due to dengue illness, were recruited into this study. A total of 515 patients participated in the study. Among them, 333 were DHF patients while 182 patients were managed as DF. There was a significant difference in mean values of platelets and haemoglobin observed during acute phase in non-leakers compared to the patients who progressed to DHF, while no significant difference was observed for white blood cells, neutrophils, lymphocytes and haematocrit values. A significantly higher mean value was observed in white blood cells and hemoglobin in leakers compared to non-leakers during day 5. Mean day 5 platelet value was significantly lower among leakers compared to non-leakers but no significant difference between haematocrit, neutrophil and lymphocyte values were observed. ROC curve performed for acute phase platelet values and haemoglobin values to gain a predictive value for female and male DHF patients and cut off values with high sensitivity and specificity to predict DHF could be obtained for the platelet count.