http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/5713 2026-04-06T15:24:33Z 2026-04-06T15:24:33Z Rajaramanan, T. Natarajan, M. Ravirajan, P. Senthilnanthanan, M. Velauthapillai, D. http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/9558 2023-06-12T03:59:03Z 2020-01-01T00:00:00Z

Title: Ruthenium (Ru) Doped Titanium Dioxide (P25) Electrode for Dye Sensitized Solar Cells Authors: Rajaramanan, T.; Natarajan, M.; Ravirajan, P.; Senthilnanthanan, M.; Velauthapillai, D. Abstract: In this study, P25-titanium dioxide (TiO2) was doped with ruthenium (Ru) by systematically varying the Ru content at 0.15, 0.30, 0.45 and 0.6 mol%. The synthesized Ru-doped TiO2 nanomaterials have been characterized by X-ray diffraction (XRD), Raman spectroscopy, energy-dispersive X-ray (EDX) analysis, UV-visible (UV–Vis) spectroscopy, and electrochemical impedance (EIS) spectroscopy. The XRD patterns of undoped and Ru-doped TiO2 nanomaterials confirm the presence of mixed anatase and rutile phases of TiO2 while EDX spectrum confirms the presence of Ti, O and Ru. Further, UV-visible absorption spectra of doped TiO2 nanomaterial reveal a slight red shift on Ru-doping. The short circuit current density (JSC) of the cells fabricated using the Ru-doped TiO2 photoanode was found to be dependent on the amount of Ru present in TiO2. Optimized cells with 0.3 mol% Ru-doped TiO2 electrodes showed efficiency which is 20% more than the efficiency of the control cell (η = 5.8%) under stimulated illumination (100 mWcm−2 , 1 sun) with AM 1.5 filter. The increase in JSC resulted from the reduced rate of recombination upon doping of Ru and this was confirmed by EIS analysis.

2020-01-01T00:00:00Z Raja Ratna Reddy, Y. Krishna Kumari, C. Lokanatha, O. Mamatha, S. Damodar Reddy, C. http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/9557 2023-06-12T03:53:24Z 2020-01-01T00:00:00Z

Title: Antimicrobial activity of Azadirachta Indica (neem) leaf, bark and seed extracts Authors: Raja Ratna Reddy, Y.; Krishna Kumari, C.; Lokanatha, O.; Mamatha, S.; Damodar Reddy, C. Abstract: Screening of medicinal plants for bioactive compounds leads to development of less expensive new antimicrobial agents with improved safety and efficacy. Azadirachta Indica (neem) is a multipurpose tree with multiple health benefits. Different parts of the plant are shown to exhibit antimicrobial effects against a wide variety of microorganisms. In the present study we compared the antimicrobial efficacy of aqueous extracts of leaf, bark and seeds of A. Indica against human pathogenic bacteria (Staphylococcus aureus, Enterococcus feacalis, Proteus mirabilis and Pseudomonas aeuroginosa) and fungi (Aspergillus fumigatus and Candida albicans). Agar well diffusion method and micro-broth dilution methods were used to determine the minimum inhibitory concentration (MIC). Results showed that leaf extract exhibited strong antimicrobial activity against bacteria and fungi at all the concentrations tested (500, 1000 and 2000µg/ml). Antimicrobial activity of bark extract was found to be moderate on bacteria and fungi (effective at 1000 and 2000µg/ml), whereas seed extract exhibited least antimicrobial activity. Minimum inhibitory concentration (MIC) of leaf and bark extract was found to be in the range of 500 to 2000µg/ml for all the tested microorganisms, where as the seed extract did not inhibit the microorganisms at all the concentrations tested except Candida albicans (1000µg /ml). Our results suggest that aqueous extracts of Azadirachta Indica leaf and bark exhibit high antimicrobial activity.

2020-01-01T00:00:00Z Kalaivani, G. Prabagar, S. Uthpala Apekshani, J. Gobalarajah, R. Sittampalam, R. Prabagar, J. http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/9539 2023-06-08T06:30:17Z 2020-01-01T00:00:00Z

Title: Impact of water quality on Chronic Kidney Disease of unknown etiology (CKDu) in Thunukkai Division in Mullaitivu District, Sri Lanka Authors: Kalaivani, G.; Prabagar, S.; Uthpala Apekshani, J.; Gobalarajah, R.; Sittampalam, R.; Prabagar, J. Abstract: Background: Increase in the number of cases in Chronic Kidney Disease of Unknown etiology (CKDu) in Sri Lanka has become a health issue of national concern. Even though, Northern Province is not identified as a high-risk province, there is an increasing trend of CKDu after the end of civil war in the Northern Province. Methods: The present study was conducted in Thunukkai Division in Mullaitivu District to investigate the socio demographic and clinical pattern of CKDu patients and to evaluate the quality of their water sources. The samples were selected by using stratified purposive random sampling method which represented 29% of total CKDu patients in Thunukkai Division. Pretested structured questionnaire was administered to collect the data from the CKDu patients. The association between serum creatinine excreted by CKDu patients and the water quality parameters were determined by using linear regression model. Results: Among the patients, 80% were male with over 68% falling in the age range of 50–70. Majority (90%) were involved in agriculture related occupation. Smoking and alcohol consumption were detected as common habits among 40% of the patients. Secondarily developed, hypertension (60%) and diabetes (34%) were reported as common diseases in the area. Dug wells served as the commonest source of drinking water in the area (90% households) together with few tube wells. Physicochemistry of more than 50% of the water samples revealed higher electric conductivity, salinity, total dissolved solids, total hardness and Na levels compared to drinking water standards in Sri Lanka. Conclusions: Serum creatinine levels of the CKDu patients were significantly and negatively correlated with phosphate while positively correlated with total dissolved solids (TDS) and arsenic content of the drinking water. Geospatial mapping of TDS and arsenic in drinking water with the occurrence of higher serum creatinine levels confirmed the same trend. Thus, the total dissolved solids and arsenic in drinking water may have positive correlation with the occurrence of CKDu in Thunukkai region in the Mullaitivu District of Sri Lanka.

2020-01-01T00:00:00Z Dulanjali, S. Srikaran, R. http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/9529 2023-06-07T06:44:36Z 2022-01-01T00:00:00Z

Title: Anti-urolithiatic Activity of Andrographis Paniculata on calcium Oxalate Crystals: A preliminary in-vitro Study Authors: Dulanjali, S.; Srikaran, R. Abstract: Since centuries ago, uses of medicinal herbs to cure diseases are precious in folk and alurvedic medicinal practices. Kidney stone formation is an unbearable disease which can be found everlwhere in the world. Even in Sri Lanka the patients suffering from urolithiasis are gradually increasing. An in-vitro experimental model was prepared to evaluate the anti-urolithiatic activity of methanolic extract of Andrographispaniculataplant on pure calcium oxalate crystals. To estimate the anti-urolithiatic activity of Andrographispaniculataplant extract, the dissolution percentage ofpure calcium oxalate crystals by the plant extract was calculated and was compared with that of a standard cystonepolyherbal drug. The methanolic extract of Andrographispaniculatawas prepared by soxhlet extraction and ethanolic and aqueous extractions were prepared by soaking the powder materials for 24 hours. The titrimetric method was used to evaluate the anti-urolithiatic activity at four different concentrations such as 100 mg/L, 200 mglL,300 mg/L, and 400 mglL. Laboratory experiments were carried out on the above extract to identift the presence ofconstituent organic molecules such as alkaloids, tannin, phytosterols, terpenoids, etc. Dissolution percentage of the calcium oxalate crystals by theAndrographispaniculataplant at above concentrations were found as7l.4 (t 0.490) o/o,74.6 (t 0.2g3) o/o, g6.3 (t 0.838) o/o,and90.4(t 0.490) % respectively.5g.6 (!0.432) o/o,64.2(+ 0.163) o/o,74.8(+ 0.283) o/o, and 78.3(t 0.249) % of calcium oxalate crystals were dissolved by the standard drug at the same concentration gradient. Qualitative analysis of ethanolic and aqueous extracts of Andrographispaniculatashowed the presence of saponin, Tannin, and Terpenoids. This preliminary research revealed the enhanced dibsolution ability of calcium oxalate crystals by Andrographispaniculata plant extract. Further in-vitro and clinical studies are required to estimate the anti-urolithiatic activity of Andrographispaniculata. Subsequently, the separation of active compounds in Andrographispaniculataplant extract can lead to the discovery ofnew drugs in the future.

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