65 research outputs found

    Study Of Mechanical Properties Of Aluminium Lm25 Using Stir Casting Method

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    The present study deals with the behaviour of aluminium hybrid alloy based composites, reinforced with fly ashnbsp particles and solid lubricants such as activated carbon .The first one of the composites consists of Al. with fly ash particlesnbsp and activated carbon. The other composite has Al with fly ash and solid lubricant: activated carbon at solid state. Both composites are fabricated through lsquoStir Casting Methodrsquo. Mechanical properties of the samples are measured by usual methods such as Hardness,Tensile .The tested samples are examined using Scanning Electron microscope (SEM) for the characterization of microstructure on the surface of composites. The Main Aim is to be results of the proposed Hybrid composites are compared with Al based metal matrix composites at corresponding values of test parameters

    Comparative epidemiology and factors associated with major healthcare-associated methicillin-resistant Staphylococcus aureus clones among interconnected acute-, intermediate- and long-term healthcare facilities in Singapore

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    Funding: Bioinformatics and Computational Biology analyses were supported by the University of St Andrews Bioinformatics Unit that is funded by a Wellcome Trust ISSF award (grant 097831/Z/11/Z). M.T.G.H is supported by the Scottish Infection Research Network and Chief Scientist Office through the Scottish Healthcare Associated Infection Prevention Institute consortium funding (CSO Reference: SIRN10).Objectives Methicillin-resistant Staphylococcus aureus(MRSA) has spread across countries and healthcare settings, with different ecological niches for different clones. It is crucial to understand the comparative epidemiology of MRSA clones between healthcare settings, and independent factors associated with colonization of specific clones. Methods We conducted annual cross-sectional surveillance studies in a network comprising an acute-care hospital and six closely-affiliated intermediate- and long-term care facilities in Singapore, in June-July, 2014-2016. 5,394 patients contributed 16,045 nasal, axillary and groin samples for culture and MRSA isolates for whole genome sequencing. Multivariable multilevel multinomial regression models were constructed to assess for independent factors associated with MRSA colonization. Results MRSA clonal complex(CC) 22 was more prevalent in the acute-care hospital(n=256/493; 51.9%) and intermediate-care(n=348/634; 54.9%) than long-term care(n=88/351; 25.1%) facilities, with clones besides CC22 and CC45 being more prevalent in long-term care facilities(n=144/351; 41.0%) (P<0.001). Groin colonization with CC45 was 6 times that of nasal colonization(aOR 6.21, 95%CI 4.26-9.01). Prior MRSA carriage was associated with increased odds of current MRSA colonization in all settings, with a stronger association with CC22(aOR 6.45, 95%CI 3.85-10.87) than CC45(aOR 4.15, 95%CI 2.26-7.58). Conclusions Colonization of MRSA clones differed between anatomic sites and across healthcare settings. With CC22 having a predilection for the nares and CC45 the groin, MRSA screening should include both sites. Prior MRSA carriage is a risk factor for colonization with predominant MRSA clones in the acute-care hospital and intermediate- and long-term care facilities. Contact precautions for prior MRSA-carriers on admission to any healthcare facility could prevent intra- and inter-institutional MRSA transmission.PostprintPeer reviewe

    Household air pollution and blood pressure, vascular damage and sub-clinical indicators of cardiovascular disease in older Chinese adults

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    Background Limited data suggest that household air pollution from cooking and heating with solid fuel (i.e., coal and biomass) stoves may contribute to the development of hypertension and vascular damage. Methods Using mixed-effects regression models, we investigated the associations of household air pollution with blood pressure (BP) and vascular function in 753 adults (ages 40-79y) from three diverse provinces in China. We conducted repeated measures of participants’ household fuel use, personal exposure to fine particulate air pollution (PM2.5), BP, brachial-femoral pulse wave velocity (bfPWV), and augmentation index. Ultrasound images of the carotid arteries were obtained to assess intima-media thickness (CIMT) and plaques. Covariate information on socio-demographics, health behaviors, 24-h urinary sodium, and blood lipids was also obtained. Results Average estimated yearly personal exposure to PM2.5 was 97.5 μg/m 3 (SD: 79.2; range: 3.5-1241), and 65% of participants cooked with solid fuel. In multivariable models, current solid fuel use was associated with higher systolic (2.4 mmHg, 95%CI: -0.4, 4.9) and diastolic BP (1.4 mmHg, 95%CI: -0.1, 3.0) and greater total area of plaques (1.7 mm 2, 95%CI: -6.5, 9.8) compared with exclusive use of electricity or gas stoves. A 1-ln(µg/m 3) increase in PM2.5 exposure was associated with higher systolic (1.5 mmHg, 95%CI: 0.2, 2.7) and diastolic BP (1.0 mmHg, 95%CI: 0.4, 1.7) and with greater CIMT (0.02 mm, 95%CI: 0.00, 0.04) and total area of plaques (4.7 mm 2, 95%CI: -2.0, 11.5). We did not find associations with arterial stiffness, except for a lower bfPWV (-1.5 m/s, 95%CI: -3.0, -0.0) among users of solid fuel heaters. Conclusions These findings add to limited evidence that household air pollution is associated with higher BP and with greater CIMT and total plaque area

    Differences in physical activity domains, guideline adherence, and weight history between metabolically healthy and metabolically abnormal obese adults: a cross-sectional study

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    BACKGROUND: Despite the accepted health consequences of obesity, emerging research suggests that a significant segment of adults with obesity are metabolically healthy (MHO). To date, MHO individuals have been shown to have higher levels of physical activity (PA), but little is known about the importance of PA domains or the influence of weight history compared to their metabolically abnormal (MAO) counterpart. OBJECTIVE: To evaluate the relationship between PA domains, PA guideline adherence, and weight history on MHO. METHODS: Pooled cycles of the National Health and Nutritional Examination Survey (NHANES) 1999–2006 (≥20 y; BMI ≥ 30 kg/m(2); N = 2,753) and harmonized criteria for metabolic syndrome (MetS) were used. Participants were categorized as “inactive” (no reported PA), “somewhat active” (>0 to < 500 metabolic equivalent (MET) min/week), and “active” (PA guideline adherence, ≥ 500 MET min/week) according to each domain of PA (total, recreational, transportation and household). Logistic and multinomial regressions were modelled for MHO and analyses were adjusted for age, sex, education, ethnicity, income, smoking and alcohol intake. RESULTS: Compared to MAO, MHO participants were younger, had lower BMI, and were more likely to be classified as active according to their total and recreational PA level. Based on total PA levels, individuals who were active had a 70 % greater likelihood of having the MHO phenotype (OR = 1.70, 95 % CI: 1.19–2.43); however, once stratified by age (20–44 y; 45–59 y; and; ≥60 y), the association remained significant only amongst those aged 45–59 y. Although moderate and vigorous PA were inconsistently related to MHO following adjustment for covariates, losing ≥30 kg in the last 10 y and not gaining ≥10 kg since age 25 y were significant predictors of MHO phenotype for all PA domains, even if adherence to the PA guidelines were not met. CONCLUSION: Although PA is associated with MHO, the beneficial effects of PA may be moderated by longer-term changes in weight. Longitudinal analysis of physical activity and weight change trajectories are necessary to isolate the contribution of duration of obesity, PA behaviours, and longer-term outcomes amongst MHO individuals

    An Estimate of the Numbers and Density of Low-Energy Structures (or Decoys) in the Conformational Landscape of Proteins

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    The conformational energy landscape of a protein, as calculated by known potential energy functions, has several minima, and one of these corresponds to its native structure. It is however difficult to comprehensively estimate the actual numbers of low energy structures (or decoys), the relationships between them, and how the numbers scale with the size of the protein.We have developed an algorithm to rapidly and efficiently identify the low energy conformers of oligo peptides by using mutually orthogonal Latin squares to sample the potential energy hyper surface. Using this algorithm, and the ECEPP/3 potential function, we have made an exhaustive enumeration of the low-energy structures of peptides of different lengths, and have extrapolated these results to larger polypeptides.We show that the number of native-like structures for a polypeptide is, in general, an exponential function of its sequence length. The density of these structures in conformational space remains more or less constant and all the increase appears to come from an expansion in the volume of the space. These results are consistent with earlier reports that were based on other models and techniques

    Cross-sectional study of household solid fuel use and renal function in older adults in China

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    Background Emerging evidence links outdoor air pollution and declined renal function but the relationship between household air pollution and renal function is not well understood. Methods Using cross-sectional data from the multi-provincial INTERMAP-China Prospective Study, we collected blood samples and questionnaire information on stove use and socio-demographic factors. We calculated estimated glomerular filtration rate (eGFR) from serum creatinine to assess renal function. Participants with eGFR <60 mL/min per 1.73 m2 were defined as having chronic kidney disease (CKD) in this analysis. Generalized estimating equations were used to estimate the association of household fuel with renal function and prevalent CKD in models adjusting for confounders. Results Among the 646 enrolled adults (40-79y; 56% female), one-third exclusively used clean fuel (gas and electric) cookstoves and 11% of northern China participants (n = 49 of 434) used only clean fuel heaters, whereas the rest used solid fuel. In multivariable models, use of solid fuel cookstoves was associated with 0.17 ml/min/1.73 m2 (95% CI: −0.30, 0.64) higher eGFR and 19% (0.86, 1.64) higher prevalence of CKD than exclusive clean fuel use. Greater intensity of solid fuel use was associated with 0.25 ml/min/1.73 m2 (−0.71, 0.21) lower eGFR per 5 stove-use years, though the confidence intervals included the null, while greater current intensity of indoor solid fuel use was associated with 1.02 (1.00, 1.04) higher prevalent CKD per 100 stove-use days per year. Larger associations between current solid fuel use and intensity of use with lower eGFR and prevalent CKD were observed among participants in southern China, those with hypertension or diabetes (eGFR only), and females (CKD only), through these groups had small sample sizes and some confidence intervals included the null. Conclusion We found inconsistent evidence associating household solid fuel use and renal function in this cross-sectional study of peri-urban Chinese adults

    Optimization of production, biochemical characterization and In Vitro evaluation of the therapeutic potential of fibrinolytic enzymes from a new Bacillus Amyloliquefaciens

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    The capacity of fibrinolytic enzymes to degrade blood clots makes them of high relevance in medicine and in the pharmaceutical industry. In this work, forty-three microorganisms of the genus Bacillus were evaluated for their potential to produce fibrinolytic proteases. Thirty bacteria were confirmed as producers of fibrinolytic enzymes, the best results obtained for the strain Bacillus amyloliquefaciens UFPEDA 485. The optimization of the enzyme production conditions was done by a central composite design (CCD) star 23 that allowed to define the optimal conditions for soybean flour and glucose concentrations and agitation rate. The highest fibrinolytic activity (FA) of 813 U mL-1 and a degradation of blood clot in vitro of 62% were obtained in a medium with 2% (w/v) of soybean flour and 1% (w/v) glucose at 200 rpm after 48 h of cultivation, at pH 7.2 and 37 °C. The obtained fibrinolytic enzyme was characterized biochemically. Fibrinolytic activity was inhibited by PMSF (fluoride methylphenylsulfonyl - C7H7FO2S) 91.52% and EDTA (ethylenediaminetetraacetic acid - C10H16N2O8) 89.4%, confirming to be a serine- metallo protease. The optimum pH and temperature were 7.0 and 37 oC, respectively, and the enzyme was stable for 12 h. The fibrinolytic activity at physiological conditions of this enzyme produced by Bacillus amyloliquefaciens UFPEDA 485, as well as its long term stability, demonstrate that it has suitable characteristics for human and veterinary applications, and promises to be a powerful drug for the treatment of vascular diseases.We express our thanks to Coordination for the Improvement of Higher Level Education Personnel (CAPES) - Doctoral Sandwich Program (PDSE) Nº 0259/ 12-8 and National Council for Scientific and Technological Development (CNPq) - Nº 202026/2011-6 for the financial support

    MRSA transmission dynamics among interconnected acute, intermediate-term, and long-term healthcare facilities in Singapore

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    This work was supported by the Ministry of Health, Singapore (Communicable Diseases–Public Health Research Grant), the Wellcome Trust (Institutional Strategic Support Fund award [grant 097831/Z/11/Z] to the University of St Andrews Bioinformatics Unit), and the Scottish Infection Research Network and Chief Scientist Office (Scottish Healthcare Associated Infection Prevention Institute consortium funding [Chief Scientist Office reference SIRN10] to K. P. and M. T. G. H.).Background: Methicillin-resistant Staphylococcus aureus (MRSA) is the most common healthcare-associated multidrug-resistant organism. Despite the interconnectedness between acute care hospitals (ACHs) and intermediate- and long-term care facilities (ILTCFs), the transmission dynamics of MRSA between healthcare settings is not well understood. Methods: We conducted a cross-sectional study in a network comprising an ACH and 5 closely affiliated ILTCFs in Singapore. A total of 1700 inpatients were screened for MRSA over a 6-week period in 2014. MRSA isolates underwent whole-genome sequencing, with a pairwise single-nucleotide polymorphism (Hamming distance) cutoff of 60 core genome single-nucleotide polymorphisms used to define recent transmission clusters (clades) for the 3 major clones. Results: MRSA prevalence was significantly higher in intermediate-term (29.9%) and long-term (20.4%) care facilities than in the ACH (11.8%) (P < .001). The predominant clones were sequence type [ST] 22 (n = 183; 47.8%), ST45 (n = 129; 33.7%), and ST239 (n = 26; 6.8%), with greater diversity of STs in ILTCFs relative to the ACH. A large proportion of the clades in ST22 (14 of 21 clades; 67%) and ST45 (7 of 13; 54%) included inpatients from the ACH and ILTCFs. The most frequent source of the interfacility transmissions was the ACH (n = 28 transmission events; 36.4%). Conclusions: MRSA transmission dynamics between the ACH and ILTCFs were complex. The greater diversity of STs in ILTCFs suggests that the ecosystem in such settings might be more conducive for intrafacility transmission events. ST22 and ST45 have successfully established themselves in ILTCFs. The importance of interconnected infection prevention and control measures and strategies cannot be overemphasized.PostprintPeer reviewe
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