Mycobacterium tuberculosis Acetyltransferase Suppresses Oxidative Stress by Inducing Peroxisome Formation in Macrophages

Mycobacterium tuberculosis (Mtb) inhibits host oxidative stress responses facilitating its survival in macrophages; however, the underlying molecular mechanisms are poorly understood. Here, we identified a Mtb acetyltransferase (Rv3034c) as a novel counter actor of macrophage oxidative stress responses by inducing peroxisome formation. An inducible Rv3034c deletion mutant of Mtb failed to induce peroxisome biogenesis, expression of the peroxisomal β-oxidation pathway intermediates (ACOX1, ACAA1, MFP2) in macrophages, resulting in reduced intracellular survival compared to the parental strain. This reduced virulence phenotype was rescued by repletion of Rv3034c. Peroxisome induction depended on the interaction between Rv3034c and the macrophage mannose receptor (MR). Interaction between Rv3034c and MR induced expression of the peroxisomal biogenesis proteins PEX5p, PEX13p, PEX14p, PEX11β, PEX19p, the peroxisomal membrane lipid transporter ABCD3, and catalase. Expression of PEX14p and ABCD3 was also enhanced in lungs from Mtb aerosol-infected mice. This is the first report that peroxisome-mediated control of ROS balance is essential for innate immune responses to Mtb but can be counteracted by the mycobacterial acetyltransferase Rv3034c. Thus, peroxisomes represent interesting targets for host-directed therapeutics to tuberculosis.     

Investigations into dry-sliding wear behaviour of a novel composite (aluminium-magnesium-silicon-copper-silicon carbide) produced by powder metallurgy route

Metal-matrix aluminium composites are satisfactory successor not only for steels, but also for aluminium-alloys in several automotive units and components. There are various paths to get light-weight materials with-out compromising their toughness, strength and safety demands. Tests on dry-sliding or un-lubricated pin-on-disc tests can be performed to obtain the wear-characteristics of metal-matrix composites built on aluminum. In the present study, we studied the behavior of wear resistance during sliding of metal matrix aluminium composites (AMMC) at sliding speeds of 1.5 m/s and loads of 20 N and 40 N in a normal environment, and experiments have been conducted using pin-on-disk tribometer (Make: DUCOM tribometer). The composites were manufactured by powder treatment and presented a number of problems, such as defective bonds and inter-facial product reactions, which alter the tribological and mechanical properties. The results have shown that wear-rates of the prepared composites are much lesser than those of matrix-alloy and decreased further with increasing silicon carbide content. As the normal loads increases, the cracks and combination of abrasions, delimitation and wear of the adhesives of silicon carbide particles were observed. The composite samples were studied using a scanning electron microscope before and after the wear tests and systematically analysed.     

Analysis of 3D signatures recorded using leap motion sensor

Multimedia Tools and Applications - Signature recognition is identifying the signature’s owner, whereas verification is the process to find whether a signature is genuine or forged. Though,...     

Removal of Congo Red dye from aqueous solution using Amberlite IRA-400 in batch and fixed bed reactors

Removal of Congo Red (CR) azo dye by adsorption process using Amberlite IRA-400 resin was evaluated in both batch and fixed bed system. From the batch adsorption results, maximum loading efficiency (99.99%) of CR dye was obtained at the conditions pH 4.5, temp. 303?K, contact time 180?min., Amberlite IRA-400 dose 0.5?g. The isotherm study ascertained on favorability of adsorption process as the value of separation factor (K_L?=?0.88) and Freundlich constant (1/n?=?0.96?R²?=?0.99) than Freundlich model (R²?=?0.97). The kinetic data studied at three different CR dye concentration (50, 75, 100?mg) and results were fitted with both pseudo-first-order and second-order model equations. The values of R² obtained are of 0.95 and 0.99 for former and later one, respectively, ensuring on best fitting of pseudo-second-order kinetics and also suggesting about the chemisorptions type of adsorption. The bed depth service model was applied for competitive analysis of the CR dye adsorption in column variables indicating mass transfer from aqueous solution to Amberlite IRA-400 phase. Fourier transform infrared analysis of CR-loaded resin Amberlite IRA-400 showed a band shifted from 1057 to 1130?cm^?1 confirming CR adsorption with Amberlite IRA-400. Scanning electron microscope analysis of resin before and after adsorption was well evident from the phase patterns. Selective separation of CR dye from waste effluent of a textile industry bearing CR dye along with other trace heavy metal was achieved.     

Macroporous open cell polyester amphigel using citric acid and PEO: Solvent absorption,thermal behavior,and slow release of pesticide

This article describes citric acid cross-linked amphiphilic poly(ethylene oxide) (PEO) macroporous open cell polyester amphigel, optimally synthesized using response surface methodology by applying central composite design to screen significant reaction parameters for maximizing percent water sorption. The chemical structure of the amphigel was confirmed by proton nuclear magnetic resonance (¹H NMR), FT-IR and the thermal behavior was studied using thermo-gravimetric and DSC. Due to amphiphilic nature, the amphigels also showed high chloroform (1151.33%–1193.33%) and water (755.33%–865%) absorption capacity. Thermal analysis revealed that amphigels are less thermal stability as compared to PEO, however, the degradation process was found to be multi step. The amphigel was effectively used as a carrier for easy loading of a hydrophobic pesticide and showed a slow release of the same.     

A comprehensive study on evolutionary algorithm‐based multilayer perceptron for real‐world data classification under uncertainty

In the area of neurocognition, classification of data is one of the most important phases. Conventional biologically inspired neural network models such as multilayer perceptrons (MLPs) are capable of learning and generalizing from exemplary patterns and are considered to be a popular choice for many different classification tasks. However, in the area of cognitive research, there lies a certain degree of uncertainty in acquired data. This uncertainty may be regarded as fuzziness. In this work, an attempt has been made to classify data which are associated with certain uncertainty. The resulting model is named as “FMLP.” Further, MLP sometimes suffers from local minima problem during the training phase. To overcome the problem of getting trapped in the local minima in error back propagation, three different population‐based evolutionary metaheuristics (genetic algorithm, particle swarm optimisation, and gravitational search) have been implemented for training the FMLP. The resulting models are evaluated for seven real‐world benchmark datasets, and it has been found that the implemented models could demonstrate exemplary performance for real‐world data classification problems under uncertainty.     

Porous textured ceramics with controlled grain size and orientation

Texture in ceramics can enhance their functional and structural properties. Current methods for texturation in dense ceramics employ plate-like particles or microplatelets as starting powders and processes that drive their orientation into specific directions. Using ultra-low magnetic fields combined with slip casting, it is possible to purposely orient magnetically responsive particles in any direction. Here, we explore the application of magnetic slip casting to bimodal slurries containing alumina nanoparticles and alumina microplatelets of various dimensions to create texture in ceramics with different grain sizes. After sintering, the obtained ceramics show anisotropic grains with controllable orientations, grain length of 3–7 μm, mild open porosity between 30–40 %, and interesting cracking behavior. Textured porous ceramics with tunable grain dimensions and orientations are promising for filtering, biomedical or composite applications.     

DC electrical resistivity and magnetic studies in Yttrium Barium Copper oxide/barium titanate composite thin films

YBCO + BaTiO₃ composite thin film is synthesized by pulsed laser deposition. Fluctuations on the electrical conductivity were investigated for zero fields. The logarithmic plots of excess conductivity and reduced temperature reveals two distinct regions namely mean field region and short wave fluctuation region. Dimensionality crossover occurs from 3D to 2D at temperature above the transition temperature. The contribution of weak link effect is calculated. The phase formation and grain alignments were analyzed by X-ray diffraction and scanning electron microscopy techniques. Enhancement of flux pinning increases the critical current density in the composite and develops strong pinning force in the material.     

Geometrical modeling of 3D woven spacer fabrics as reinforcement for lightweight sandwich composites

Lightweight sandwich composites mainly utilize hollow textile preforms as their reinforcement. The production of such structures with desired mechanical properties requires monitoring of its repeat unit weight and fibre volume fraction (FVF) from designing stage itself. In this work, mathematical expressions have been developed using fabric geometrical parameters which can calculate the areal density and FVF of a repeat unit of 3D hollow woven structures. Five samples each of trapezoidal and rectangular spacer configurations were produced with different cell structural parameters and materials to validate the model. It was found that the computed results for both the weight and FVF were in good correlation with experimental results, with prediction accuracy being more than 90% in all cases. It was also found that with increase in the cell dimensions, the FVF of the expanded fabric decreases.