Probing the in vitro binding mechanism between human serum albumin and La2 O2 CO3 nanoparticles

The interaction of La₂ O₂ CO₃ nanoparticles (La NPs) with human serum albumin (HSA) has been studied. Analysis of the fluorescence quenching data of HSA using Stern–Volmer method showed that La NPs quenched HSA fluorescence in static quenching mode. Thermodynamic analysis indicated that hydrogen bonds and Van der Waals interactions play a major role for HSA–La NPs associations. Fluorescent displacement measurements confirmed that the primary binding site of La NPs was mainly located within site I (subdomain IIA) of HSA. The binding distance was calculated by using Forster resonance energy transfer theory. Also, the results of Fourier‐transform infrared spectroscopy, circular dichroism, three‐dimensional fluorescence and UV–visible measurements indicated that the binding of above La NPs to HSA may induce conformational and micro‐environmental changes of protein. This study suggested that the conformational change of HSA was at secondary structure of it and the biological activity of this protein was changed in the present of La NPs.Inspec keywords: proteins, molecular biophysics, molecular configurations, nanoparticles, lanthanum compounds, fluorescence, radiation quenching, thermal analysis, biothermics, biochemistry, hydrogen bonds, van der Waals forces, Fourier transform infrared spectra, circular dichroism, visible spectra, ultraviolet spectra, nanobiotechnologyOther keywords: in vitro binding mechanism, human serum albumin, La₂ O₂ CO₃ nanoparticles, Stern‐Volmer method, La NPs quenched HSA fluorescence, static quenching mode, thermodynamic analysis, hydrogen bonds, Van der Waals interactions, HSA‐La NPs associations, fluorescent displacement measurements, primary binding site, subdomain IIA, binding distance, Forster resonance energy transfer theory, Fourier‐transform infrared spectroscopy, circular dichroism, three‐dimensional fluorescence, UV‐visible measurements, conformational changes, microenvironmental changes, protein, secondary structure, La₂ O₂ CO₃      

Dual extended composite right/left‐handed transmission line metamaterial

The new concept of dual extended composite right/left‐handed transmission line (D‐ECRLH TL), with 2 right handed and 2 left handed frequency bands is presented. The D‐ECRLH TL and extended composite right/left handed transmission line are structurally dual. Therefore, the proposed TL shows the dual properties of the ECRLH TL. The D‐ECRLH indeed behaves as a dual‐band bandstop filter, in opposition to the ECRLH which is a dual‐band bandpass one. In contrast, the D‐ECRLH creates an unlimited LH bandwidth. In this article, the transmission parameters and the fundamental properties of the D‐ECRLH TL (dispersion and impedance diagrams) are investigated. The results show that the proposed structure is suitable to design the quad‐band microwave circuits and systems. A prototype of the proposed D‐ECRLH unit cell is realized by the microstrip technology. The good agreement between the measurement and simulation results confirms the realizability of the proposed structure.     

Theoretical model for multiple breakup of fluid particles in turbulent flow field

Generalized phenomenological model, based on the theories of probability and isotropic turbulence, is developed for multiple breakup of fluid particles in turbulent flow field. The approach uses a series of successive binary breakup events occur at a time scale comparable to the colliding eddy turnover time. It was found that the use of energy density, instead of energy, will increase the predicted binary breakup rate which is usually underestimated by the existing models in the literature. Generalization of the binary breakup model for multiple fragmentations is performed by defining a “remaining energy function” for the colliding eddy which means the contribution of original eddy to the later breakup events. For ternary breakage, the model shows a reasonably good agreement with the experimental data. The quaternary fragmentation frequency, however, is of negligible importance at lower energy dissipation rates but its contribution to breakage fraction at higher energy dissipation rates becomes considerable. The results also show that ternary and quaternary breakups have a considerable 90% contribution to the overall fragmentation, while pentenary and further fragmentations are of lower importance at low energy dissipation rates. At higher levels of energy dissipation rate, fragmentations up to six daughter particles contribute to more than 95% of the overall fragmentations. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4508–4525, 2016     

Combustion of petroleum residue in a batch type fixed bed reactor

Combustion is a highly efficient technology for energy conversion of biomass materials, municipal wastes, and fossil fuels. In this study, combustion tests of two petroleum residues (P1, P2) in a batch type fixed-bed reactor were presented for different operating conditions. The effects of air flow rate (50–70 L/min) on the combustion parameters (gas temperature and carbon conversion) were performed. Additionally, the influence of fuel flow rate on the environmental characteristics (NO_x emissions) was evaluated. The experimental results demonstrated that air flow rate is the most important factor in the process; a higher air fuel rate contributed to higher NO_x emissions and gas temperature. It also was found that the NO_x emissions increase dramatically when the air flow rate increases.     

MODELING OF BUOYANCY-DRIVEN FLOW AND HEAT TRANSFER FOR AIR IN A HORIZONTAL ANNULUS: EFFECTS OF VERTICAL ECCENTRICITY AND TEMPERATURE-DEPENDENT PROPERTIES

In this article fluid dynamic and thermal fields are presented for numerical simulations of laminar, steady, two-dimensional buoyancy-driven flows in an annulus between two vertically eccentric pipes using the penalty finite element method. The simulations were accomplished for Rayleigh numbers between 10 3 and 10 5 and radius ratio of 2.6, with various eccentricities. For most of the work, the usual Boussinesq approximation was made. However, in order to demonstrate the effects of temperature-dependent physical properties for natural convection in a concentric annulus, a modified Boussinesq approximation with temperature-dependent viscosity and thermal conductivity has been used. The formulation was based on primitive variables. Numerical results are presented in terms of isotherms, streamlines, and Nusselt numbers. The results are compared with recent publications and excellent agreement has been found. Stable solutions were obtained when the model was modified to incorporate temperature-dependent viscosity and thermal conductivity and applied to the case of a concentric annulus. The varying viscosity had the most effect on the fluid velocity, while the effects of varying thermal conductivity were most noticeable in the temperature profiles and local Nusselt numbers.     

Multilateral Analysis of Pressure and Temperature Effects on Steam Methane Reforming Reaction

Abstract

Pressure and temperature effects on steam methane reforming (SMR) process in porous media and at equilibrium conditions of the reaction were investigated. The investigation was carried out by developing of a computer program to check the simultaneous effects of pressure and temperature on the extent of the reaction. Two methods for estimation of the effective diffusivity coefficients through porous catalysts were applied: (a) simplified method and (b) a new method based on more realistic conditions of the reaction. The results obtained based on this study would be useful for optimizing of pressure and temperature of SMR reaction.     

Improved phantom cell deployment for capacity enhancement

Wireless Networks - Vastly increasing capacity and coverage demand in communication networks accompanied by energy efficiency challenge is getting attraction in research topics of this area. In...     

Hydrogen and CO2 Management in the Refinery with Fuzzy Multiobjective Nonlinear Programming

An innovative approach for optimization of the hydrogen network in a refinery is presented. The optimization problem was formulated as a fuzzy‐based multiobjective nonlinear programming (FMONLP), aiming at simultaneous minimization of the total annual cost and CO₂ emission. This is achieved by defining an objective function with a weighted sum of the annual cost and CO₂ emission. The weighting factors are considered as fuzzy parameters which are described based on the experts' experiences. The applicability of the proposed approach is illustrated by optimization of an Iranian refinery hydrogen network.