769 research outputs found

    Effect of streamwise spacing on the sound generated by flow through two square cylinders in tandem arrangement

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    The sound generated by the flow past two square cylinder in tandem arrangements was investigated by direct solution of two dimensiona1, unsteady, compressible Navier-Stokes equation. The main objective of the investigation is to study the effect of the spacing between two square cylinders on the generation and propagation mechanism of the sound. Since the sound pressure is very small compared to normal pressure and other parameters, high order computational scheme was use to captured the pressure fluctuations. Besides that, filtering is em-ployed to eliminate the high frequency part caused by nonlinearity of the governing equations. 4th order Runge-Kutta method was employed for time marching and for the boundary condition, adiabatic and non-slip conditions are imposed on the surface of the square cylinders. Present results for near-field flow features are in good agreement with the experimental results by previous researchers though the Reynolds number ranges examined are different. From the results, it shows that tandem arrangement of two cylinders with a small spacing may be useful for a passive control to reduce the generated sound since the larger spacing (L/D > 4), the shear layer separated from the upstream cylinder rolls up and forms vortices in front of the downstream cylinder. The results also showed that body-vortex interaction enhances the amplitude of the generated sound significantly

    Efficacy of Aquatain, a Monomolecular Film, for the Control of Malaria Vectors in Rice Paddies

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    Background Rice paddies harbour a large variety of organisms including larvae of malaria mosquitoes. These paddies are challenging for mosquito control because their large size, slurry and vegetation make it difficult to effectively apply a control agent. Aquatain, a monomolecular surface film, can be considered a suitable mosquito control agent for such breeding habitats due to its physical properties. The properties allow Aquatain to self-spread over a water surface and affect multiple stages of the mosquito life cycle. Methodology/Principal Findings A trial based on a pre-test/post-test control group design evaluated the potential of Aquatain as a mosquito control agent at Ahero rice irrigation scheme in Kenya. After Aquatain application at a dose of 2 ml/m2 on rice paddies, early stage anopheline larvae were reduced by 36%, and late stage anopheline larvae by 16%. However, even at a lower dose of 1 ml/m2 there was a 93.2% reduction in emergence of anopheline adults and 69.5% reduction in emergence of culicine adults. No pupation was observed in treated buckets that were part of a field bio-assay carried out parallel to the trial. Aquatain application saved nearly 1.7 L of water in six days from a water surface of 0.2 m2 under field conditions. Aquatain had no negative effect on rice plants as well as on a variety of non-target organisms, except backswimmers. Conclusions/Significance We demonstrated that Aquatain is an effective agent for the control of anopheline and culicine mosquitoes in irrigated rice paddies. The agent reduced densities of aquatic larval stages and, more importantly, strongly impacted the emergence of adult mosquitoes. Aquatain also reduced water loss due to evaporation. No negative impacts were found on either abundance of non-target organisms, or growth and development of rice plants. Aquatain, therefore, appears a suitable mosquito control tool for use in rice agro-ecosystems

    Use of B2O3 films grown by plasma-assisted atomic layer deposition for shallow boron doping in silicon

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    Plasma-assisted atomic layer deposition (PALD) was carried for growing thin boron oxide films onto silicon aiming at the formation of dopant sources for shallow boron doping of silicon by rapid thermal annealing (RTA). A remote capacitively coupled plasma source powered by GaN microwave oscillators was used for generating oxygen plasma in the PALD process with tris(dimethylamido)borane as boron containing precursor. ALD type growth was obtained; growth per cycle was highest with 0.13 nm at room temperature and decreased with higher temperature. The as-deposited films were highly unstable in ambient air and could be protected by capping with in-situ PALD grown antimony oxide films. After 16 weeks of storage in air, degradation of the film stack was observed in an electron microscope. The instability of the boron oxide, caused by moisture uptake, suggests the application of this film for testing moisture barrier properties of capping materials particularly for those grown by ALD. Boron doping of silicon was demonstrated using the uncapped PALD B2O3 films for RTA processes without exposing them to air. The boron concentration in the silicon could be varied depending on the source layer thickness for very thin films, which favors the application of ALD for semiconductor doping processes.Investment Bank Berlin and EFR

    Essential medicines management during emergencies in Pakistan

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    This paper illustrates the experiences of essential medicine management in providing cure and care to victims of Pakistan\u27s 2005 earthquake in a safe, rational and effective mode. The health interventions assured access to essential medicine, sustained supply, inventory control through a computerized logistic support system and rational use of medicines. World Health Organization Pakistan outlined modalities for acceptance of donated medicines, assisted in speedy procurement of medicines and designed customized kits. Proper storage of medicines at controlled temperature was ensured in warehousing facilities in 12 locations. A steady supply of medicines and their consumption without stock-outs in the 56 first-level care facilities of calamity-hit areas helped to ascertain the average consumption and cost of essential medicines and supplies for the catchment population. Tools for quantification and forecasting of medicines and supplies were developed and shared. Medicines and medical supplies were efficiently used resulting in minimum wastage

    Incidence of shoulder dystocia and its relation to brachial plexus palsy: a 10 year retrospective review at King Abdulaziz University Hospital

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    Background: Objective of the study was to determine the incidence of shoulder dystocia (SD) in King Abdulaziz University Hospital (KAUH), with a focus on Brachial Plexus Palsy (BPP) and the accompanying risk factors.Methods: We conducted a retrospective study of all vaginal deliveries between 2005 and 2014. Out of 29,199 vaginal deliveries, 236 cases where diagnosed with SD at KAUH in Jeddah, KSA. The following maternal and perinatal variables were reviewed by the patients' medical records: (booking status, maternal age, gestational age, maternal Body Mass Index (BMI), presence of diabetes, previous history of SD, instrumental delivery, Birth weight, Erb's and Klumpke's palsies).Results: A total of 236 cases had SD with an incidence of (0.8%). Only 55 cases among all had BPP. The Erb's palsy was found in 54 cases (30.7%) while Klumpke's palsy was found only in one case (0.6%). There were 121 (68.8%) cases with no BPP and a remaining of 60 unknown BPP outcomes. From the total number of cases with SD, mothers with overweight and obesity were found in 93% of the cases.Conclusions: Most of clinically diagnosed SD cases did not give the consequence of BPP. However, this complication in addition to other complications of SD mandates extra caution in cases with risk factors

    Antibacterial efficacy of indigenous Pakistani honey against extensively drug-resistant clinical isolates of Salmonella enterica serovar Typhi: an alternative option to combat antimicrobial resistance

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    Abstract Background Extensively drug-resistant (XDR) Salmonella enterica serovar Typhi (S. Typhi) poses a grave threat to public health due to increased mortality and morbidity caused by typhoid fever. Honey is a promising antibacterial agent, and we aimed to determine the antibacterial activity of honey against XDR S. Typhi. Methods We isolated 20 clinical isolates of XDR S. Typhi from pediatric septicemic patients and determined the minimum inhibitory concentrations (MICs) of diferent antibiotics against the pathogens using the VITEK 2 Compact system. Antimicrobial-resistant genes carried by the isolates were identifed using PCR. The antibacterial efcacy of fve Pakistani honeys was examined using agar well difusion assay, and their MICs and minimum bactericidal concentrations (MBCs) were determined with the broth microdilution method. Results All 20 isolates were confrmed as S. Typhi. The antibiogram phenotype was confrmed as XDR S. Typhi with resistance to ampicillin (≥32 µg/mL), ciprofoxacin (≥4 µg/mL), and ceftriaxone (≥4 µg/mL) and sensitivity to azithromycin (≤16 µg/mL) and carbapenems (≤1 µg/mL). Molecular conformation revealed the presence of blaTM-1, Sul1, qnrS, gyrA, gyrB, and blaCTX-M-15 genes in all isolates. Among the fve honeys, beri honey had the highest zone of inhibition of 7–15 mm and neem honey had a zone of inhibition of 7–12 mm. The MIC and MBC of beri honey against 3/20 (15%) XDR S. Typhi isolates were 3.125 and 6.25%, respectively, while the MIC and MBC of neem were 3.125 and 6.25%, respectively, against 3/20 (15%) isolates and 6.25 and 12.5%, respectively, against 7/20 (35%) isolates. Conclusion Indigenous honeys have an efective role in combating XDR S. Typhi. They are potential candidates for clinical trials as alternative therapeutic options against XDR S. Typhi isolates. Keywords Antimicrobial resistance, Natural antibiotics, XDR S. Typhi, MIC, Honey, Resistance gene

    Influence of Sleeve Gastrectomy on NASH and Type 2 Diabetes Mellitus

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    Background. Nonalcoholic fatty liver disease is present in up to 85% of adipose patients and may proceed to nonalcoholic steatohepatitis (NASH). With insulin resistance and obesity being the main risk factors for NASH, the effect of isolated sleeve gastrectomy (ISG) on these parameters was examined. Methods. 236 patients underwent ISG with intraoperative liver biopsy from December 2002 to September 2009. Besides demographic data, pre-operative weight/BMI, HbA1c, AST, ALT, triglycerides, HDL and LDL levels were determined. Results. A significant correlation of NASH with higher HbA1c, AST and ALT and lower levels for HDL was observed (P < .05, <.0001, <.0001, <.01, resp.). Overall BMI decreased from 45.0 ± 6.8 to 29.7 ± 6.5 and 31.6 ± 4.4 kg/m2 at 1 and 3 years. An impaired weight loss was demonstrated for patients with NASH and patients with elevated HbA1c (plateau 28.08 kg/m2 versus 29.79 kg/m2 and 32.30 kg/m2 versus 28.79 kg/m2, resp.). Regarding NASH, a significant improvement of AST, ALT, triglyceride and HDL levels was shown (P < .0001 for all). A resolution of elevated HbA1c was observed in 21 of 23 patients. Summary. NASH patients showed a significant loss of body weight and amelioration of NASH status. ISG can be successfully performed in these patients and should be recommended for this subgroup

    Network analysis of human muscle adaptation to aging and contraction.

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    This is the final version. Available from Impact Journals via the DOI in this record. Resistance exercise (RE) remains a primary approach for minimising aging muscle decline. Understanding muscle adaptation to individual contractile components of RE (eccentric, concentric) might optimise RE-based intervention strategies. Herein, we employed a network-driven pipeline to identify putative molecular drivers of muscle aging and contraction mode responses. RNA-sequencing data was generated from young (21±1 y) and older (70±1 y) human skeletal muscle before and following acute unilateral concentric and contralateral eccentric contractions. Application of weighted gene co-expression network analysis identified 33 distinct gene clusters ('modules') with an expression profile regulated by aging, contraction and/or linked to muscle strength. These included two contraction 'responsive' modules (related to 'cell adhesion' and 'transcription factor' processes) that also correlated with the magnitude of post-exercise muscle strength decline. Module searches for 'hub' genes and enriched transcription factor binding sites established a refined set of candidate module-regulatory molecules (536 hub genes and 60 transcription factors) as possible contributors to muscle aging and/or contraction responses. Thus, network-driven analysis can identify new molecular candidates of functional relevance to muscle aging and contraction mode adaptations.Wellcome Trust Institutional Strategic Support AwardBiotechnology and Biological Sciences Research Counci

    Interface modification of clay and graphene platelets reinforced epoxy nanocomposites: a comparative study

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    The interface between the matrix phase and dispersed phase of a composite plays a critical role in influencing its properties. However, the intricate mecha-nisms of interface are not fully understood, and polymer nanocomposites are no exception. This study compares the fabrication, morphology, and mechanical and thermal properties of epoxy nanocomposites tuned by clay layers (denoted as m-clay) and graphene platelets (denoted as m-GP). It was found that a chemical modification, layer expansion and dispersion of filler within the epoxy matrix resulted in an improved interface between the filler mate-rial and epoxy matrix. This was confirmed by Fourier transform infrared spectroscopy and transmission electron microscope. The enhanced interface led to improved mechanical properties (i.e. stiffness modulus, fracture toughness) and higher glass transition temperatures (Tg) compared with neat epoxy. At 4 wt% m-GP, the critical strain energy release rate G1c of neat epoxy improved by 240 % from 179.1 to 608.6 J/m2 and Tg increased from 93.7 to 106.4 �C. In contrast to m-clay, which at 4 wt%, only improved the G1c by 45 % and Tg by 7.1 %. The higher level of improvement offered by m-GP is attributed to the strong interaction of graphene sheets with epoxy because the covalent bonds between the carbon atoms of graphene sheets are much stronger than silicon-based clay
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