Ultrasound-assisted,low-solvent and acid/base-free synthesis of 5-substituted 1,3,4-oxadiazole-2-thiols as potent antimicrobial and antioxidant agents

Molecular Diversity - One of the goals of green chemistry is to use environmentally friendly solvents or remove and reduce the volume of harmful spent solvents. In this study, a novel process for...     

Synthesis of new functionalized reduced graphene oxide quantum dot composite for high-performance NO2 gas sensor

Research on Chemical Intermediates - In this research, synthesis of a novel magnetic 2-naphthalenesulfonic acid-grafted reduced graphene oxide quantum dot (Fe3O4-rGOQD-naphthalene-2-SO3H) via a...     

Calculation of Viscosity and Diffusion Coefficients for Two Binary Gaseous Mixtures Using the Semi-empirical Inversion Method

The accurate reduced potential energies for two binary gas mixtures including benzene-methanol and methane-tetrafluoromethane at low density have been obtained by direct inversion of the viscosity collision integral equations. The kinetic theory along with the extended principle of corresponding-states has been used to calculate the viscosity and dif-fusion coefficients over a wide range of temperature and composition. Good agreements between calculated and experimental data are obtained.     

The effects of Knudsen-dependent flow velocity on vibrations of a nano-pipe conveying fluid

In this paper, we investigate the effect of nano-flow on vibration of nano-pipe conveying fluid using Knudsen (Kn). We use Euler–Bernoulli plug-flow beam theory. We modify no-slip condition of nano-pipe conveying fluid based on Kn. We define a Kn-dependent flow velocity. We consider effect of slip condition, for a liquid and a gas flow. We reformulate Navier–Stokes equations, with modified versions of Kn-dependent flow velocity. We observe that for passage of gas through nano-pipe with nonzero Kn, the critical flow velocities decreased considerably as opposed to those for zero Kn. This can show that ignoring Kn effect on a gas nano-flow may cause non-conservative design of nano-devices. Furthermore, a more impressive phenomenon happens in the case of clamped-pinned pipe conveying gas fluid. While we do not observe any coupled-mode flutter for a zero Kn, we can see the coupled-mode flutter, accompanying the second-mode divergence, for a nonzero Kn.     

Fluorosis Caused Cellular Apoptosis and Oxidative Stress of Rat Kidneys

As the strongest electronegative element, fluorine can stimulate the production of superoxide radicals in cells. In view of the important roles of kidneys in bone metabolism, the authors analyzed the quantitative pathomorphological characteristics of renal damage and the potential cellular apoptosis and oxidative stress mechanisms in rats treated with excessive fluoride. Wistar rats were exposed to 50 mg F^-(110.5 mg NaF)/L, 100 mg F^-(221.0 mg NaF)/L and 150 mg F^-(331.5 mg NaF)/L in drinking water for 70 and 140 d, respectively. Microscope with image analysis was used to quantitate pathomorphological changes in renal tissues of the rats. Reactive oxygen species(ROS), the cell cycle and apoptosis of renal cells were measured by flow cytometry and TUNEL technique(terminal deoxynucleotidyl transferase dUTP nick end labeling), respectively. The ion concentrations in serum and renal functional parameters were detected by automatic biochemical analyzer. Quantitative analysis results demonstrate the expanded Bowman’s space of glomerulus and obvious dilatation of renal tubule. TUNEL technique revealed that NBT/BCIP (nitro blue tetrazolium/5-bromo-4-chloro-3′-indolylphosphate, p-toluidine salt)-staining positive apoptotic cells selectively located in medullocortical junction areas. The data suggest that renal damage in chronic fluorostic rats is associated with the cellular apoptosis and oxidative stress.     

Buckling behavior of perfect and defective DWCNTs under axial, bending and torsional loadings via a structural mechanics approach

The buckling behavior of perfect and defective double-walled carbon nanotubes (DWCNTs) under axial compressive, torsional and bending loadings is investigated using a structural mechanics model. The effects of van der Waals (vdW) forces are further modeled using a nonlinear spring element. Critical buckling loads, critical buckling moments and the effects of vacancy defects were studied for armchair nanotubes with various aspect ratios. The results show that vacancy defects greatly reduce the critical buckling load of DWCNTs. The density of defects plays an important role in buckling of DWCNTs. The results of this numerical model are in good agreement with their comparable existing works.     

PPA-SiO_2 as a Heterogeneous Catalyst for Efficient Synthesis of 2-Substituted-1,2,3,4-tetrahydro-4-quinazolinones under Solvent-free Conditions

Silica‐supported polyphosphoric acid (PPA‐SiO₂) catalyzed efficiently the reaction of anthranilamide with aryl aldehydes or ketones under solvent‐free conditions to afford the corresponding 1,2,3,4‐tetrahydro‐4‐quinazolinone derivatives. This work consistently has the advantages of excellent yields, short reaction time, simple experimental and work‐up procedures. The heterogeneous catalyst could be recovered and recycled for several times without any loss of its activity.     

Catalytic oxidation of urazoles and bis-urazoles to their corresponding triazolinediones using aluminium nitrate and a catalytic amount of silica sulfuric acid

Abstract  A simple and efficient catalytic oxidation of urazoles and a bis-urazole to the corresponding triazolinediones by treatment with Al(NO₃)₃.9H₂O in the presence of a catalytic amount of silica sulfuric acid is described. A good range of urazole derivatives was selectively oxidized in CH₂Cl₂ at room temperature in good to excellent yields. Graphical abstract