The Bayesian and Approximate Bayesian Methods in Small Area Estimation

For small area estimation, model based methods are preferred to the traditional design based methods because of their ability to borrow strength from related sources. The indirect estimates, obtained using mixed models, are usually more reliable than the direct survey estimates. To draw inferences from mixed models, one can use Bayesian or frequentist approach. We consider the Bayesian approach in this dissertation. The Bayesian approach is straightforward. The prior and likelihood produce the posterior, which is used for all inferential purposes. It overcomes some of the shortcomings of the empirical Bayes approach. For example, the posterior variance automatically captures all sources of uncertainties in estimating small area parameters. But this approach requires the specification of a subjective prior on the model parameters. Moreover, in almost all situation, the posterior moments involve multi-dimensional integration and consequently closed form expressions cannot be obtained. To overcome the computational difficulties one needs to apply computer intensive MCMC methods. We apply linear mixed normal models (area level and unit level) to draw inferences for small areas when the variable of interest is continuous. We propose and evaluate a new prior distribution for the variance component. We use Laplace approximation to obtain accurate approximations to the posterior moments. The approximations present the Bayesian methodology in a transparent way, which facilitates the interpretation of the methodology to the data users. Our simulation study shows that the proposed prior yields good frequentist properties for the Bayes estimators relative to some other popular choices. This frequentist validation brings in an objective flavor to the so-called subjective Bayesian approach. The linear mixed models are, usually, not suitable for handling binary or count data, which are often encountered in surveys. To estimate the small area proportions, we propose a binomial-beta hierarchical model. Our formulation allows a regression specification and hence extends the usual exchangeable assumption at the second level. We carefully choose a prior for the shape parameter of the beta density. This new prior helps to avoid the extreme skewness present in the posterior distribution of the model parameters so that the Laplace approximation performs well

Amelioratory Effect of Nanoconjugated Vancomycin on Spleen during VRSA-Induced Oxidative Stress

Objective. The aim of the present study was to evaluate the possible antioxidant effects of nanoconjugated vancomycin against VRSA infection on select makers of oxidative damage and antioxidant status in spleen. Methods. A coagulase-positive VRSA strain was used for this study. VRSA infection was developed in Swiss mice by intraperitoneal injection of 5 × 106 CFU/mL bacterial solutions. VRSA-infected mice were treated with nanoconjugated vancomycin at its effective dose for 10 days. After decapitation, blood was used for determination of viable bacteria count and spleen was excised from control and experimental groups, homogenized and used for different biochemical estimations. Results. Nitrate level, myeloperoxidase activity, lipid peroxidation, protein oxidation, oxidized glutathione, and DNA fragmentation level were increased significantly (P < 0.05) in spleen of VRSA-infected group as compared to control group, and reduced glutathione level, activity of SOD, CAT, GPx, GR, and GST were decreased significantly (P < 0.05); which were increased or decreased significantly (P < 0.05) near to normal in nanoconjugated vancomycin-treated group. Conclusion. These findings suggest the potential use and beneficial role of nanoconjugated vancomycin against VRSA-infection-induced oxidative stress and DNA damage in spleen

Internalization of Staphylococcus aureus in Lymphocytes Induces Oxidative Stress and DNA Fragmentation: Possible Ameliorative Role of Nanoconjugated Vancomycin

Staphylococcus aureus is the most frequently isolated pathogen causing bloodstream infections, skin and soft tissue infections and pneumonia. Lymphocyte is an important immune cell. The aim of the present paper was to test the ameliorative role of nanoconjugated vancomycin against Vancomycin-sensitive Staphylococcus aureus (VSSA) and vancomycin-resistant Staphylococcus aureus (VRSA) infection-induced oxidative stress in lymphocytes. VSSA and VRSA infections were developed in Swiss mice by intraperitoneal injection of 5 × 106 CFU/mL bacterial solutions. Nanoconjugated vancomycin was adminstrated to VSSA- and VRSA-infected mice at its effective dose for 10 days. Vancomycin was adminstrated to VSSA- and VRSA-infected mice at a similar dose, respectively, for 10 days. Vancomycin and nanoconjugated vancomycin were adminstrated to normal mice at their effective doses for 10 days. The result of this study reveals that in vivo VSSA and VRSA infection significantly increases the level of lipid peroxidation, protein oxidation, oxidized glutathione level, nitrite generation, nitrite release, and DNA damage and decreases the level of reduced glutathione, antioxidant enzyme status, and glutathione-dependent enzymes as compared to control group, which were increased or decreased significantly near to normal in nanoconjugated vancomycin-treated group. These findings suggest the potential use and beneficial role of nanoconjugated vancomycin against VSSA and VRSA infection-induced oxidative stress in lymphocytes

Discrimination of green tea using an Epigallocatechin-3-gallate (EGCG) sensitive molecular imprinted polymer (MIP) based electrode

In this work, a simple approach of discriminating green tea samples has been proposed using an epigallocatechin-3-gallate (EGCG) sensitive molecular imprinted polymer (MIP) electrode modified with chemically synthesized nickel hydroxide (Ni(OH)2) nanoparticles. The nanoparticles were characterized by powder X-ray diffraction techniques (XRD) and the removal of the template molecule has been ascertained by UV-vis spectroscopy. A three electrode system has been employed to study the electrochemical characteristics of the electrode by means cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Four different kinds of preprocessing techniques, namely – (i) Baseline subtraction, (ii) Autoscale, (iii) Relative scale 1 and (iv) Relative scale 2 were applied on the obtained data set and the best preprocessing technique was optimized. Further, principal component analysis (PCA) and linear discriminant analysis (LDA) were implemented on the preprocessed data set so as to observe the discrimination ability of the electrode on the basis of EGCG content in green tea. The separability index (SI) values for both PCA and LDA plots is calculated and it is observed that baseline subtraction provided the best result with a SI value of 8.72 and 16.01, respectively

A novel syngas-fired hybrid heating source for solar-thermal applications: Energy and exergy analysis

A hybrid heating source using biomass-derived syngas is proposed to enable continuous operation of standalone solar thermal power generation plants. A novel, two-stage, low temperature combustion system is proposed that has the potential to provide stable combustion of syngas with near-zero NO emissions. The hybrid heating system consists of a downdraft gasifier, a two-stage combustion system, and other auxiliaries. When integrated with a solar cycle, the entire system can be referred to as the integrated gasification solar combined cycle (IGSCC). The supercritical CO2 Brayton cycle (SCO2) is selected for the solar cycle due to its high efficiency. The thermodynamic performance evaluation of the individual unit and the combined system has been conducted from both energy and exergy considerations. The effect of parameters such as gasification temperature, biomass moisture content, equivalence ratio, and pressure ratio is studied. The efficiency of the IGSCC exhibited a non-monotonic behavior. A maximum thermal efficiency of 36.5% was achieved at an overall equivalence ratio of 0.22 and pressure ratio of 2.75 when the gasifier was operating at T-g = 1073 K with biomass containing 20% moisture. The efficiency increased to 40.8% when dry biomass was gasified at a temperature of 973 K. The exergy analysis revealed that the maximum exergy destruction occurred in the gasification system, followed by the combustion system, SCO2 cycle, and regenerator. The exergy analysis also showed that 8.72% of the total exergy is lost in the exhaust; however, this can be utilized for drying of the biomass. (C) 2016 Elsevier Ltd. All rights reserved

Effect of N-2 dilution and preheat temperature on combustion dynamics of syngas in a reverse-flow combustor

The present study investigates the combustion dynamics of low-calorific value syngas in the reverse-flow configuration at P = 1 atm using OH* chemiluminescence (5 kHz), noise (50 kHz), and emissions (NOx and CO) measurements. The combustion dynamics have been investigated as a function of the global equivalence ratio (0.32-0.89), percentage O-2 in the coflow (7.6-21%), and the oxidizer preheat temperature (similar to 400-800 K). The variation of these parameters resulted in different operating conditions such as conventional, ultra-lean, transition, and MILD combustion modes. For all the cases, autoignition kernels were observed arid appear to be a possible mode of flame stabilization - highlighting the role of H-2 in reducing the ignition delay. The combustion chamber demonstrated stable operation over the range of equivalence ratio and percentage O-2 investigated, with the conventional mode displaying the highest SPL and fluctuations in the reaction zone (OH*). The most stable operation was obtained for the MILD case where the SPL decreased by similar to 6 dB caused by a suppression of the high-frequency (> 800 Hz) longitudinal modes. However, the operation of the combustion chamber became unstable as the oxidizer preheat temperature decreased from 603-547 K due to the emergence of very high-frequency (similar to 9-15 kHz) oscillations