Cytotoxic effect,enzyme inhibition,and in silico studies of some novel N-substituted sulfonyl amides incorporating 1,3,4-oxadiazol structural motif

Molecular Diversity - The acetylcholinesterase and carbonic anhydrase inhibitors (AChEIs and hCAIs) remain key therapeutic agents for many bioactivities such as anti-Alzheimer and antiobesity...     

Experimental investigation of flow and heat transfer in rectangular cross-sectioned duct with baffles mounted on the bottom surface with different inclination angles

In this study, steady-state forced convection heat transfer and pressure drop characteristics in a horizontal rectangular cross-sectioned duct, baffles mounted on the bottom surface with different inclination angles were investigated experimentally in the Reynolds number range from 1 × 10³ to 1 × 10⁴. The study was performed under turbulent flow conditions. Effects of different baffle inclination angles on flow and heat transfer were studied. Results are also presented in terms of thermal enhancement factor. It is observed that increasing in baffle inclination angle enhances the heat transfer and causes an increase in pressure drop in the duct.     

Preparation and probe analysis of Langmuir–Blodgett films with metal-containing dendritic and cluster structures

We aim to reveal the influence of?pH values of the working solution on spatial arrangement of metal-containing inclusions in the monolayer coatings prepared by Langmuir?CBlodgett (LB) technology and transferred to solid substrates with consequent modification of surface electrical properties. Consequently, films with inclusions in the form of dendrites and cluster shapes have been obtained. Submicron and micron lead-containing formations in Langmuir?CBlodgett films have been characterized by using the atomic force microscopy, Kelvin probe microscopy, and scanning electron microscopy methods. The results show that increasing?pH value of the subphase has caused the significant changes in the shape and composition of the inclusions in Langmuir?CBlodgett films. The synthesized inclusions on the solid substrate surface resulted in formation of the regions with the local electric fields and, as consequence, to significant modification of the structure and electrical properties. The location and length of the regions with surface potential disturbance depend on the shape of inclusions, and consequently, on?pH value of the subphase used in LB technology.     

Crystallization kinetic studies on Bi1.75Pb0.25Sr2Ca2Cu3-xSnxOδ glass-ceramic by using non-isothermal technique

The Sn substituted Bi_1.75Pb_0.25Sr₂Ca₂Cu_3-xSnxO_δ glass ceramic (where x = 0, 0.1, 0.3, and 0.5) samples were prepared by the melt-quenching method. Crystallization kinetic studies of the samples were conducted using the differential thermal analysis (DTA). The oxidation behavior of the samples was also analyzed using the thermogravimetry analysis (TG). The DTA curves were registered with different heating rates (5, 10, 15, and 20 Kmin^? 1) up to 1200 ± 0.5 K. The crystallization results were analyzed, and activation energy of crystallization process as well as the crystallization mechanisms and the effect of Sn substitution on powder glass ceramic were characterized. The glass transition temperature (T_g), the first crystallization peak temperature (T_x1) and the second crystallization peak temperature (T_x2) values were obtained as 713.0 ± 0.5–746.6 ± 0.5, 731.0 ± 0.5–760.8 ± 0.5 and 789.0 ± 0.5–820.1 ± 0.5 K, respectively. The activation energy (E_a) of crystallization was estimated from DTA results to be about 332.8 ± 0.1, 358.0 ± 0.1, 353.1 ± 0.1 and 348.9 ± 0.1 kJ/mol for x = 0, 0.1, 0.3 and 0.5, respectively, by using the Kissinger method. The Avrami parameter (n) values calculated at different Sn ratio from DTA results were found to be between 1.70 ± 0.01 and 2.57 ± 0.01, results reflect the growth of small particle with a decreasing nucleation rate.     

Elastic-plastic states of two-layer curved bar under pure bending

Analytical solution of an elastic-partially plastic two-layer curved bar subjected to couples at both ends is obtained. The solution is based on Tresca's yield criterion and its associated flow rule. Numerical results for real engineering materials in partially plastic stress state are presented in graphical form. (© 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Measurement of ambient fluid entrainment during laminar vortex ring formation

Planar laser induced fluorescence (PLIF) and digital particle image velocimetry (DPIV) combined with Lagrangian coherent structure (LCS) techniques are utilized to measure ambient fluid entrainment during laminar vortex ring formation and relate it to the total entrained volume after formation is complete. Vortex rings are generated mechanically with a piston-cylinder mechanism for a jet Reynolds number of 1,000, stroke ratios of 0.5, 1.0 and 2.0, and three velocity programs (Trapezoidal, triangular negative and positive sloping velocity programs). The quantitative observations of PLIF agree with both the total ring volume and entrainment rate measurements obtained from the DPIV/LCS hybrid method for the jet Reynolds number of 1,000, trapezoidal velocity program and stroke ratio of 2.0 case. In addition to increased entrainment at smaller stroke ratios observed by others, the PLIF results also show that a velocity program utilizing rapid jet initiation and termination enhances ambient fluid entrainment. The observed trends in entrainment rate and final entrained fluid fraction are explained in terms of the vortex roll-up process during vortex ring formation.     

Elastic-plastic states of a rotating inhomogeneously heated strain hardening hollow shaft

Based on Tresca's yield criterion and the flow rule associated with it, the behaviour of a linearly strain-hardening elastic-plastic hollow shaft subject to a positive radial temperature gradient and monotonously increasing angular speed is studied. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Chemometrics-Assisted Optimization of Beta-/Gamma-Tocol Separation on a C<Subscript>30</Subscript> Stationary Phase in Reversed-Phase LC

This paper presents a chemometrics-assisted optimization study to improve the separation of tocopherol (-T) and tocotrienol (-TT) homologues on a C₃₀ stationary phase in reversed-phase HPLC. The HPLC settings were optimized using a central composite design and the response surface methodology. Flow rate, column temperature, and mobile phase composition were chosen as independent variables. Peak resolution (R_s), analysis time (t_R), and peak symmetries of the tocopherol isomers were chosen as response variables. Optimum performance in terms of R_s was obtained at a flow rate of 0.31 mL min^?1, a temperature of 8.70 °C, and % B content (methyl tert-butyl ether: methanol: water, 80:18:2, v/v/v) in the mobile phase of 38.12%. The analysis of variance and regression analysis gave adjusted R² values of 0.9841 for R_s, 0.9850 for t_R-(α-T), 0.9853 for t_R-(β-T), and 0.9204 for the peak symmetry of β-T. This confirms the good agreement of experimental data with predicted values. The close eluting peaks of β-/γ-tocol could be baseline separated at the optimized conditions at a minimized analysis time. Empirical second-order polynomial models were derived that gave statistically high significances (P?<?0.0001). Hence, the models can be successfully employed to predict the optimum separation conditions of co-eluting peaks of β-/γ-tocols. The optimized method was successfully applied to determine the individual tocol homologues in various cold pressed edible oils. Total contents ranged from 15 to almost 2600 mg tocol kg^?1 oil.     

An unexpected and unusual V(5+)10 cluster containing oxygen bridges as well as six bidentate acetylacetonates

Structural Chemistry - A cluster of 10 vanadium (5+) atoms bridged by 22 oxygen atoms and having six of the vanadiums around the periphery each bound to a single bidentate acetylacetone is...