940 research outputs found

    Genetic variability of camel (Camelus dromedarius) populations in Saudi Arabia based on microsatellites analysis

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    The genetic diversity and population genetic structure of dromedary camels (Camelus dromedarius) are poorly documented in Saudi Arabia. The present study was conducted to address some of these genetics using four Saudi Arabian camel populations namely; Magaheem (MG), Maghateer (MJ), Sofr (SO) and Shual (SH). Genomic DNA was extracted from the hair roots of 160 camels, 40 individuals from each population. Sixteen microsatellite markers were used to genotype these 160 camels. Out of these 16 markers, only microsatellite VOLP67 did not produce any polymerase chain reaction (PCR) amplicons. There were 139 alleles generated by the 15 microsatellites loci with a mean of 9.27 alleles per locus. Four of the microsatellites loci studied in MG, eight in MJ and six in both SO and SH were found to be deviated from Hardy-Weinberg equilibrium. The fixation genetic indices (Fst) among the four populations were very low, ranging from 0.006 (between SH and SO) to 0.017 (between MG and MJ), indicating low population differentiation among the four Saudi camel populations. No significant heterozygote excess or bottleneck in most nearest past was detected in the four camel populations as indicated by sign, standardized differences and Wilcoxon tests, along with the normal L shaped distribution of mode-shift test. The present study showed that the microsatellite markers are powerful tools in breeding programs, although there is a need for applying more microsatellites in order to be able to discriminate fairly between camel populations of Saudi Arabia.Keywords: Camels, Camelus dromedarius, microsatellite markers, Saudi Arabia, genetic variabilit

    Flow boiling in microchannels with HFE-7100: Experimental results and comparison with correlations

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    An experimental investigation of flow boiling heat transfer in a copper multi-microchannel heat sink with a hydraulic diameter of 0.46 mm is described in this paper. The heat sink consisted of 25 rectangular microchannels, which were 0.7 mm wide, 0.35 mm deep and 25 mm long. The separating wall thickness between the channels was 0.1 mm and the width of the heat sink was 20 mm giving a base area of 500 mm2. HFE-7100 was chosen as the test fluid due to its environmentally friendly nature and high dielectric strength. It was also considered a suitable choice for cooling electronic components that require working surface temperature between 80 °C to 125 °C. A high-speed, high-resolution camera was used to capture the flow patterns during the experiments. All experiments were performed at a system pressure of 1 bar, inlet sub-cooling temperature of 5 K, mass flux ranging from 50 to 250 kg/m2 s and a heat flux range of 43.96−335.29 kW/m2. Four flow patterns were observed namely bubbly, slug, churn and annular flow. It was found that the local heat transfer coefficient increases with increasing heat flux and decreases slightly with increasing vapour quality, while there is a negligible effect of mass flux. The experimental results were compared with a number of existing heat transfer correlations that were proposed for macro and micro scale with some correlations showing good agreement. Similar comparisons with pressure drop correlations were also included

    Multi-perspective evaluation of integrated active cooling systems using fuzzy decision making model

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    As global median temperatures continue to rise, the demand for active cooling systems (ACs) is increasing. These systems are particularly prevalent in developed countries for maintaining comfort during hot weather. Various ACs technologies are available, and assessing their performance in multi-perspective settings is necessary to determine the best option for intended usage. This requires an evaluation platform for assessment. This paper presents a novel multi-criteria decision-making (MCDM) model based on a new integrated 2-tuple linguistic Pythagorean fuzzy-weighted zero-inconsistency (2 TLP-FWZIC) and modified 2-tuple linguistic Pythagorean fuzzy multi-attributive border approximation area comparison (2TLPF-MABAC). The former is used to determine the importance of assessment criteria, while the latter is employed for selecting the optimal ACs using the obtained weights. The first-level weighting results reveal that performance criteria were predominantly favored for assessment, with ‘energy performance’ acquiring the most significant weight (0.2487) among all performance criteria. In terms of ACs selection results, among the 20 tested and assessed systems, the ‘geothermal borehole electricity-based ACs’ obtained the highest score value (0.1296), while the ‘window packaged electricity-based ACs’ had the lowest score (-0.0515). The robustness of the results was confirmed through sensitivity analysis

    Averrhoa carambola leaves prevent dyslipidemia and oxidative stress in a rat model of poloxamer-407-induced acute hyperlipidemia

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    Background: The star fruit [Averrhoa carambola L (Oxalidaceae)] is traditionally used in the treatment of many ailments in many countries. It possesses several pharmacological activities, including antioxidant and anti-inflammatory effects. However, it contains the neurotoxic caramboxin and its high content of oxalic acid limits its consumption by individuals with compromised kidney function. This study assessed the anti-hyperlipidemic and antioxidant activities of different fractions of the methanolic extract of A. carambola leaves (MEACL). Methods: The antioxidant activity was investigated using FRAP, and ABTS and DPPH radical-scavenging assays and the inhibitory activity toward pancreatic lipase (PL) and HMG-CoA reductase was assayed in vitro. Acute hyperlipidemia was induced by poloxamer-407 (P-407) in rats and different fractions of MEACL (n-hexane, chloroform, n-butanol, ethyl acetate (EA), water, and chloroform) were orally administered. Cholesterol and triglycerides were determined at 0, 12, 24, and 48 h and LDL-C, vLDL-C, HDL-C, lipid peroxidation (LPO) and antioxidants were assayed after 48 h. The expression of ABCA1, ABCG5, ABCG8, LDL-R, SREBP-1, and SREBP-2 and the activity of HMG-CoA reductase were assayed in the liver of P-407-administered rats treated with the EA fraction. Results: The in vitro data revealed potent radical-scavenging activities of MEACL fractions with the most potent effect showed by the EA fraction that also suppressed the activities of HMG-CoA reductase and PL. In P-407-induced hyperlipidemic rats, all fractions prevented dyslipidemia as shown by the decrease in total cholesterol, triglycerides, LDL-C, vLDL-C and atherogenic index. MEACL and its fractions prevented LPO and boosted GSH, superoxide dismutase, glutathione peroxidase, and catalase in P-407-administered rats. The EA fraction showed more effective anti-hyperlipidemic and antioxidant effects than other fractions and downregulated SREBP-2 while upregulated ABCA1 and LDL-R and ameliorated LPL and HMG-CoA reductase in hyperlipidemic rats. Conclusion: MEACL showed in vitro and in vivo antioxidant activity and the EA fraction significantly ameliorated dyslipidemia in a rat model of P-407-induced acute hyperlipidemia by modulating LPL, PL, HMG-CoA reductase, and cholesterolgenesis-related factors. Therefore, the leaves of A. carambola represent a safe alternative for the star fruit particularly in kidney disease patients, and the EA is the most effective anti-hyperlipidemic and antioxidant fraction

    Effect of myrrh and thyme on Trichinella spiralis enteral and parenteral phases with inducible nitric oxide expression in mice

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    Trichinellosis is a serious disease with no satisfactory treatment. We aimed to assess the effect of myrrh (Commiphora molmol

    Medical students' perceptions of complementary and alternative medicine therapies: A pre- and post-exposure survey in Majmaah University, Saudi Arabia

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    Background: Evidently, Complementary and Alternative Medicine (CAM) is increasingly a recognized medical practice that efficiently uses multiple treatment therapies and techniques in promoting the health  and wellbeing of people as well as preventing and managing a variety of human disorders. Research in CAM, which courses exposure to diverse healthcare professionals, is important from many perspectives including improvement in teaching skills of faculty, enhancing capacity building, and  innovative curriculum development. This pre- and post-design crosssectional study aimed to assess perceptions, training needs, personal usage, use in office practice, and knowledge of two batches of medical students toward CAM therapies in Majmaah University, Saudi Arabia.Materials and Methods: The second year medical students of the first (year 2012-13) and second (year 2013-2014) batch [n=26 & 39, respectively] were selected for this study. A reliable 16-item  self-administered questionnaire was distributed among all students for answering before and after the 48-hour specific 19 CAM therapies course, in terms of CAM therapies are clearly conventional or  alternative, training needs, effectiveness, personal use, use in practice, management of two clinical cases by CAM or conventional therapies, and views about which evidence based approach strongly support individual CAM modalities.Results: Medical students' knowledge and perceptions of CAM therapies significantly improved across some sub-items of CAM questionnaire with a positive trend in the rest of its items including their views about CAM therapies, need for further training, personal use of therapies and advising patients regarding CAM practices strongly supported by randomized clinical controlled trials and published case studies.Conclusion: CAM course tends to have positive impact on the knowledge and perceptions of medical students, in addition to need for further training, and personal use and use of CAM therapies in practice in line with strong evidence-based data regarding therapeutic efficacy. The preliminary results of this study call for further research in specific CAM modalities with a larger sample in academic settings across the nation. Key words: Medical students; Complementary and Alternative Medicine; CAM course; CAM therapies; pre-post design study; Saudi Arabia
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