Selective oxoammonium salt oxidations of alcohols to aldehydes and aldehydes to carboxylic acids

The oxidation of alcohols to aldehydes using stoichiometric 4-acetamido-2,2,6,6-tetramethylpiperidine-1-oxoammonium tetrafluoroborate (1) in CH(2)Cl(2) at room temperature is a highly selective process favoring reaction at the carbinol center best able to accommodate a positive charge. The oxidation of aldehydes to carboxylic acids by 1 in wet acetonitrile is also selective; the rate of the process correlates with the concentration of aldehyde hydrate. A convenient and high yield method for oxidation of alcohols directly to carboxylic acids has been developed.     

Naked eye detection of nitric oxide release from nitrosothiols aided by gold nanoparticles

In this work we have demonstrated that nitric oxide can be monitored spectrophotometrically using cyclodextrin encapsulated ferrocene. The detection course showed the colour change from yellow to blue which can be detected with the naked eye. Also we describe the catalytic effect of gold nanoparticles in enhancing nitric oxide release from S-nitrosothiols.     

Functional Military Textile: Plasma-Induced Graft Polymerization of DADMAC for Antimicrobial Treatment on Nylon-Cotton Blend Fabric

In this study, diallyldimethylammonium chloride (DADMAC), a quaternary ammonium salt monomer, is graft polymerized on 50?C50 Nylon-Cotton (NyCo) standard military fabric using atmospheric pressure glow discharge plasma to impart self-detoxification capability. Atmospheric pressure plasma?is used to induce free radical chain polymerization of the DADMAC monomer to introduce a graft polymerized network on the fabric with durable antimicrobial properties. Pentaerythritol tetraacrylate (PETA) is used as a cross-linking agent to obtain a highly cross-linked, durable polymer network. The presence of polyDADMAC on the fabric surface is confirmed using acid dye staining, SEM, and TOF?CSIMS. Antibacterial performance is investigated using standard AATCC Test Method 100 for both gram positive and gram negative bacteria. Results show 99.9?% reduction in the bacterial activities of Klebsiella pneumoniae and Staphylococcus aureus.     

Defect induced local moment in ZnO as a consequence of Stoner mechanism

We have examined the formation of a local moment by considering various defects in ZnO. The localization of the defect induced state is found to determine the presence/absence of a local moment. A lot of attention on the probable origin of magnetism in wide band gap oxides has focused on cation vacancies. Here we show that oxygen interstitial atoms give rise to a large magnetic moment which results in a spin polarization of both the conduction and valence bands, in addition to spin polarized gap states. A Stoner mechanism is invoked and the relevant Stoner parameters are determined to be 0.7 eV for an oxygen atom in the presence of an oxygen interstitial but reduced to 0.2 eV on oxygen in the presence of a Zn vacancy.     

Helical folding in heterogeneous foldamers without inter-residual backbone hydrogen-bonding

This communication describes a set of hybrid foldamers that do not feature inter-residual, but intra-residual backbone hydrogen-bonding, yet adopt a preferentially folded conformation displaying right-handed helical architecture. Conformational ordering is apparently due to the combined conformational restrictions imposed by the conformationally restricted individual amino acid residues with which the oligomers are made of.     

Growth and characterization of borono phenylalanine

Borono phenylalanine abbreviated as BPA is a biologically important compound which is obtained from L‐Phenylalanine (C₉H₁₁NO₂) in which a boron atom is bonded. BPA is an amino acid analogue, helpful in the treatment of glioblastoma multiforme, a highly malignant form of brain tumor is crystallized in silica gel under pH 6.0 by single diffusion method in a period of 30 minutes. The grown crystals were characterized by x‐ray powder diffraction, Fourier Transform infrared spectroscopy and visible ultraviolet spectroscopy. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Identification of Mtb GlmU Uridyltransferase Domain Inhibitors by Ligand-Based and Structure-Based Drug Design Approaches

Targeting enzymes that play a role in the biosynthesis of the bacterial cell wall has long been a strategy for antibacterial discovery. In particular, the cell wall of Mycobacterium tuberculosis (Mtb) is a complex of three layers, one of which is Peptidoglycan, an essential component providing rigidity and strength. UDP-GlcNAc, a precursor for the synthesis of peptidoglycan, is formed by GlmU, a bi-functional enzyme. Inhibiting GlmU Uridyltransferase activity has been proven to be an effective anti-bacterial, but its similarity with human enzymes has been a deterrent to drug development. To develop Mtb selective hits, the Mtb GlmU substrate binding pocket was compared with structurally similar human enzymes to identify selectivity determining factors. Substrate binding pockets and conformational changes upon substrate binding were analyzed and MD simulations with substrates were performed to quantify crucial interactions to develop critical pharmacophore features. Thereafter, two strategies were applied to propose potent and selective bacterial GlmU Uridyltransferase domain inhibitors: (i) optimization of existing inhibitors, and (ii) identification by virtual screening. The binding modes of hits identified from virtual screening and ligand growing approaches were evaluated further for their ability to retain stable contacts within the pocket during 20 ns MD simulations. Hits that are predicted to be more potent than existing inhibitors and selective against human homologues could be of great interest for rejuvenating drug discovery efforts towards targeting the Mtb cell wall for antibacterial discovery.     

Misuse of Cardiac Lipid upon Exposure to Toxic Trace Elements—A Focused Review

Heavy metals and metalloids like cadmium, arsenic, mercury, and lead are frequently found in the soil, water, food, and atmosphere; trace amounts can cause serious health issues to the human organism. These toxic trace elements (TTE) affect almost all the organs, mainly the heart, kidney, liver, lungs, and the nervous system, through increased free radical formation, DNA damage, lipid peroxidation, and protein sulfhydryl depletion. This work aims to advance our understanding of the mechanisms behind lipid accumulation via increased free fatty acid levels in circulation due to TTEs. The increased lipid level in the myocardium worsens the heart function. This dysregulation of the lipid metabolism leads to damage in the structure of the myocardium, inclusive fibrosis in cardiac tissue, myocyte apoptosis, and decreased contractility due to mitochondrial dysfunction. Additionally, it is discussed herein how exposure to cadmium decreases the heart rate, contractile tension, the conductivity of the atrioventricular node, and coronary flow rate. Arsenic may induce atherosclerosis by increasing platelet aggregation and reducing fibrinolysis, as exposure interferes with apolipoprotein (Apo) levels, resulting in the rise of the Apo-B/Apo-A1 ratio and an elevated risk of acute cardiovascular events. Concerning mercury and lead, these toxicants can cause hypertension, myocardial infarction, and carotid atherosclerosis, in association with the generation of free radicals and oxidative stress. This review offers a complete overview of the critical factors and biomarkers of lipid and TTE-induced cardiotoxicity useful for developing future protective interventions.     

Analysis of homogeneous–heterogeneous reactions in a micropolar nanofluid past a nonlinear stretching surface: semi-analytical approach

In the present scenario, the application of reactive agents in industries plays a vital role in the production processes of various materials such as paper production, drawing of wires, etc. Keeping in mind it is necessary to discuss the application of heterogeneous and homogeneous chemical reactions in a micropolar nanofluid flow over a stretching surface where the sheet is considered to be nonlinear. In addition to that, the inclusion of heat generation/absorption in the energy equation of an electrically conducting fluid also affects the fluid flow phenomena. In the present analysis, the Maxwell model thermal conductive is considered with Fe₃O₄, CuO nanoparticles, and water is treated as base fluid. It is very much transparent that the nonlinear dimensional form of the PDEs gets transformed into ODEs and a semi-analytical approach is employed, i.e., Adomian decomposition method (ADM) for those transformed ODEs. The computation for several characterizing parameters is obtained using the mathematical package MAPLE and these are displayed via graphs and tables. An excellent concurrence with the earlier established result is found which validates the result with the current methodology.

     

Thermal behavior of carboxymethyl cellulose in the presence of polycarboxylic acid crosslinkers

Journal of Thermal Analysis and Calorimetry - In this paper, the thermodynamic (energy and exergy) analysis and water analysis of a modified solar still augmented with copper tube heat exchanger in...