Complexed sol-gel synthesis of improved Pt-Ru-Os-based anode electro-catalysts for direct methanol fuel cells

A high specific surface area (SSA) Pt-Ru-Os-based anode catalyst synthesized by a novel complexed sol-gel (CSG) process shows better catalytic activity in comparison to pure equi-atomic compositions of Pt-Ru anode catalysts synthesized by similar sol-gel processes. A homogeneous amorphous gel was successfully synthesized by complexing platinum(II) acetylacetonate, ruthenium(III) acetylacetonate and osmium(III) chloride with tetramethylammonium hydroxide (TMAH) used as a complexing agent. Phase-pure Pt(Ru,Os) and Pt(Ru) solid solutions possessing high specific surface area (∼110-120 m²/g) were successfully synthesized by controlled removal of carbonaceous species present in the as-prepared precursor generated from the CSG process. This has been successfully achieved by precise thermal treatments of the precursor using controlled oxidizing atmospheres. Results indicate that the nano-crystalline Pt(Ru,Os) solid solution of nominal composition 50 at%-Pt-40 at% Ru-10 at% Os possesses good chemical homogeneity, and reveals excellent catalytic activity, thus demonstrating the potential of the novel CSG process for synthesizing high-performance Pt-Ru-Os-based catalysts for direct methanol fuel cells.     

Biosynthesis of TiO2 nanoparticles and their superior antibacterial effect against human nosocomial bacterial pathogens

Research on Chemical Intermediates - Antibacterial titanium dioxide nanoparticles (TiO2NPs) were biologically synthesized by microwave irradiation of Cissus quadrangularis extract followed by...     

Chemokine Receptor 5 Antagonism Causes Reduction in Joint Inflammation in a Collagen-Induced Arthritis Mouse Model

Rheumatoid arthritis (RA) is a chronic inflammatory disease mainly affecting the synovial joints. A highly potent antagonist of C-C chemokine receptor 5 (CCR5), maraviroc (MVC), plays an essential role in treating several infectious diseases but has not yet been evaluated for its potential effects on RA development. This study focused on evaluating the therapeutic potential of MVC on collagen-induced arthritis (CIA) in DBA/1J mice. Following CIA induction, animals were treated intraperitoneally with MVC (50 mg/kg) daily from day 21 until day 35 and evaluated for clinical score and histopathological changes in arthritic inflammation. We further investigated the effect of MVC on Th9 (IL-9, IRF-4, and GATA3) and Th17 (IL-21R, IL-17A, and RORγT) cells, TNF-α, and RANTES in CD8+ T cells in the spleen using flow cytometry. We also assessed the effect of MVC on mRNA and protein levels of IL-9, IL-17A, RORγT, and GATA3 in knee tissues using RT-PCR and western blot analysis. MVC treatment in CIA mice attenuated the clinical and histological severity of inflammatory arthritis, and it substantially decreased IL-9, IRF4, IL-21R, IL-17A, RORγT, TNF-α, and RANTES production but increased GATA3 production in CD8+ T cells. We further observed that MVC treatment decreased IL-9, IL-17A, and RORγt mRNA and protein levels and increased those of GATA3. This study elucidates the capacity of MVC to ameliorate the clinical and histological signs of CIA by reducing pro-inflammatory responses, suggesting that MVC may have novel therapeutic uses in the treatment of RA.     

Optimal analytical and numerical approximations to the (un)forced (un)damped parametric pendulum oscillator

The (un)forced (un)damped parametric pendulum oscillator (PPO) is analyzed analytically and numerically using some simple, effective, and more accurate techniques. In the first technique, the ansatz method is employed for analyzing the unforced damped PPO and for deriving some optimal and accurate analytical approximations in the form of angular Mathieu functions. In the second approach, some approximations to (un)forced damped PPO are obtained in the form of trigonometric functions using the ansatz method. In the third approach, He's frequency-amplitude principle is applied for deriving some approximations to the (un)damped PPO. In the forth approach, He's homotopy technique is employed for analyzing the forced (un)damped PPO numerically. In the fifth approach, the p-solution Method, which is constructed based on Krylov–Bogoliúbov Mitropolsky method, is introduced for deriving an approximation to the forced damped PPO. In the final approach, the hybrid Padé-finite difference method is carried out for analyzing the damped PPO numerically. All proposed techniques are compared to the fourth-order Runge–Kutta (RK4) numerical solution. Moreover, the global maximum residual distance error is estimated for checking the accuracy of the obtained approximations. The proposed methodologies and approximations can help many researchers in studying and investigating several nonlinear phenomena related to the oscillations that can arise in various branches of science, e.g. waves and oscillations in plasma physics.