63 research outputs found
Antibacterial activity of a marine bacterium against pathogenic and environmental isolates of vibrio species
The marine environment covers three quarters of the surface of the planet is estimated to be home to more than 80% of life and yet it remains largely unexplored. The rich diversity of marine flora and fauna and its adaptation to the harsh marine environment coupled with new developments in biotechnology, has opened up a new exciting vista for extraction of bioactive products of use in medicine. In this study inhibitory activity of a marine bacterium isolated from gut of ribbonfish was studied against pathogenic and environmental isolates of Vibrio species. This strain was identified as Pseudomonas stutzeri and it was found active against V. harveyi (luminescent bacteria), V. cholerae, V. alginolyticus, V. damseal, V. fluvialis. The antibacterial substance produced by Pseudomonas stutzeri was soluble in organic solvent and closely bound to external surface of bacterial cells. Reduction of the absorbance of the V. cholera cell suspension was observed when log phase cells of V. cholerae were treated with MIC and 4xMIC concentration of crude extract of Pseudomonas stutzeri
EXTENDED MODELLING AND NUMERICAL INVESTIGATION OF PHASED ARRAY SYNTHETIC JET CROSS-FLOW INTERACTIONS
A classical analysis of incompressible unsteady Navier-Stokes equation have been under discussion for a long time by various reasearchers, it has been found that the exact analytical unique solution existed only below and undefined Reynolds number limit. Several solutions were existed for a range of Reynolds number above the limit, and that has no solution exsisted above the second undefined Reynolds number (i.e, solution enter into turbulent region and one has to solve another set of equations for turbulance). A useful study was done for two dimensional unsteady incompressible flow in which vorticity is propotional to stream function perturbed by uniform stream. Recently this unsteady sloution was used to analyse the flow behaviour on flat plate using Synthetic Jet Actuators (SJA) which consists of oscillating membrane expels in fluid through orifice. The results obtained at different time level were presented and it was found as the time progresses streamlines, on the flat plate with number of actuators placed in an array, become flatter caused rapidly decay in vortices on trailing edge. The authentication of these results were needded to be validated through experiment or numerical simulation. In this paper, an attempt has been made to solve incompressible unsteady Navier-Stokes equations numerically to analyse the behaviour of single and multiple sythetic jet actuator in a cross flow conditions. The behaviour of SJA implemented by imposing a special kind of boundary condition on the bottom of flate plate was studied. Results have been obtained for various Reynolds numbers and were presented. These numerical results were in close agreement with [1]
A Numerical Study of SIR Epidemic Model
Epidemic and infectious disease fall into the category of time dependent dynamic system. The model under consideration is SIR-type (susceptible, infectious, recovered) which assumes that every individual has equally chances to be infected by the infectious individual in the case of contact except the pair formation or those who have a sufficient immunity for the disease. The model considered in this paper is non-fatal. If the portion of the immuned population exceeds the herd immunity level then the disease will no longer persist in the population. The model is solved with and without demographical effects. The vaccination effect is also discussed along with the physical parameters. The simulations have been performed for the non-linear coupled ordinary differential equations using Runge-Kutta 4th order method and MATLAB-SIMULINK software. The results obtained by both methods are in good agreement with the existing results in the literature [7]
Development of in vitro-in vivo correlation for nimesulide loaded ethylcellulose microparticles
A predictive in vitro-invivo correlation (IVIVC) can empower in vitro dissolution as a surrogate for in vivo bioavailability / bioequivalence. IVIVCs can decrease regulatory burden by decreasing the number of biostudies required in support of a drug product. The present study concerns the establishment of in vitro-in vivo correlation for three different sustained release nimesulide loaded ethylcellulose microparticulate formulations (M1, M2 and M3) and conventional tablet (100 mg Nimaran®-Novartis, Pakistan). In vitro dissolution study was conducted in phosphate buffer pH 6.8 stirred at 50 rpm and 37 ± 0.5ºC. A validated HPLC method was adopted to conduct bioavailability studies in young healthy human volunteers. Ultimately IVIVC of prepared microparticles and conventional tablet was established using Wagner-Nelson method. M1 and M2 formulations and Nimaran® exhibited good linear IVIVC (R2 = 0.9220, 0.9124, 0.8728, respectively) as compared to M3 (R2 = 0.9449). The results substantiate the success of this mathematical simulation study encourage researchers to conduct biowaiver studies for other BCS class II drugs.Colegio de Farmacéuticos de la Provincia de Buenos Aire
Transparent encryption with scalable video communication: Lower-latency, CABAC-based schemes
Selective encryption masks all of the content without completely hiding it, as full encryption would do at a cost in encryption delay and increased bandwidth. Many commercial applications of video encryption do not even require selective encryption, because greater utility can be gained from transparent encryption, i.e. allowing prospective viewers to glimpse a reduced quality version of the content as a taster. Our lightweight selective encryption scheme when applied to scalable video coding is well suited to transparent encryption. The paper illustrates the gains in reducing delay and increased distortion arising from a transparent encryption that leaves reduced quality base layer in the clear. Reduced encryption of B-frames is a further step beyond transparent encryption in which the computational overhead reduction is traded against content security and limited distortion. This spectrum of video encryption possibilities is analyzed in this paper, though all of the schemes maintain decoder compatibility and add no bitrate overhead as a result of jointly encoding and encrypting the input video by virtue of carefully selecting the entropy coding parameters that are encrypted. The schemes are suitable both for H.264 and HEVC codecs, though demonstrated in the paper for H.264. Selected Content Adaptive Binary Arithmetic Coding (CABAC) parameters are encrypted by a lightweight Exclusive OR technique, which is chosen for practicality
The association between parity, infant gender, higher level of paternal education and preterm birth in Pakistan: a cohort study
<p>Abstract</p> <p>Background</p> <p>High rates of antenatal depression and preterm birth have been reported in Pakistan. Self reported maternal stress and depression have been associated with preterm birth; however findings are inconsistent. Cortisol is a biological marker of stress and depression, and its measurement may assist in understanding the influence of self reported maternal stress and depression on preterm birth.</p> <p>Methods</p> <p>In a prospective cohort study pregnant women between 28 to 30 weeks of gestation from the Aga Khan Hospital for Women and Children completed the A-Z Stress Scale and the Centre for Epidemiology Studies Depression Scale to assess stress and depression respectively, and had a blood cortisol level drawn. Women were followed up after delivery to determine birth outcomes. Correlation coefficients and Wilcoxon rank sum test was used to assess relationship between preterm birth, stress, depression and cortisol. Logistic regression analysis was used to determine the key factors predictive of preterm birth.</p> <p>Results</p> <p>132 pregnant women participated of whom 125 pregnant women had both questionnaire and cortisol level data and an additional seven had questionnaire data only. Almost 20% of pregnant women (19·7%, 95% CI 13·3-27·5) experienced a high level of stress and nearly twice as many (40·9%, 95% CI 32·4-49·8%) experienced depressive symptoms. The median of cortisol level was 27·40 ug/dl (IQR 22·5-34·2). The preterm birth rate was 11·4% (95% CI 6·5-18). There was no relationship between cortisol values and stress scale or depression. There was a significant positive relationship between maternal depression and stress. Preterm birth was associated with higher parity, past delivery of a male infant, and higher levels of paternal education. Insufficient numbers of preterm births were available to warrant the development of a multivariable logistic regression model.</p> <p>Conclusions</p> <p>Preterm birth was associated with higher parity, past delivery of a male infant, and higher levels of paternal education. There was no relationship between stress, and depression, cortisol and preterm birth. There were high rates of stress and depression among this sample suggesting that there are missed opportunities to address mental health needs in the prenatal period. Improved methods of measurement are required to better understand the psychobiological basis of preterm birth.</p
A Survey of Bayesian Statistical Approaches for Big Data
The modern era is characterised as an era of information or Big Data. This
has motivated a huge literature on new methods for extracting information and
insights from these data. A natural question is how these approaches differ
from those that were available prior to the advent of Big Data. We present a
review of published studies that present Bayesian statistical approaches
specifically for Big Data and discuss the reported and perceived benefits of
these approaches. We conclude by addressing the question of whether focusing
only on improving computational algorithms and infrastructure will be enough to
face the challenges of Big Data
Effect of a Physical Activity Intervention on the Metabolic Syndrome in Pakistani Immigrant Men: A Randomized Controlled Trial
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