Cover Picture: Exploring the Implications of Vitamin B12 Conjugation to Insulin on Insulin Receptor Binding (ChemMedChem 3/2009)

The cover picture shows three views of a vitamin B₁₂–insulin conjugate bound to transcobalamin II, docked in the insulin receptor (IR). This study reveals how the structure of an orally deliverable insulin changes in solution after vitamin B₁₂ conjugation and its effect on IR binding capacity. The results demonstrate that chemical modification of insulin by linking relatively large pendant groups does not interfere with IR recognition. For more details, see the Full Paper by T. J. Fairchild, R. P. Doyle, et al. on p. 421 ff.

     

利用基于PSO算法的径向基人工神经网络优化重催干气脱硫

针对重催干气脱硫过程存在进料波动频繁、优化响应滞后导致能量消耗过大等问题,通过Aspen HYSYS V11软件利用Li-Mather物性方法对该系统进行全流程模拟,根据Plackett-Burman设计筛选对目标值具有显著影响的有效因素,利用基于PSO算法的径向基人工神经网络对预测模型进行训练、验证和测试,并在满足净化干气硫化氢浓度约束的前提下对其进行深度优化,以期最小化系统能耗。结果表明,重催干气流量、重催干气硫化氢浓度、贫液哌嗪质量分数、贫液N-甲基二乙醇胺（MDEA）质量分数、胺液循环量、T-3001塔底温度和E-3003贫液出口温度对系统能耗影响非常显著,当以上述因素为输入信号,以系统能耗为网络输出时,7-16-1型径向基人工神经网络预测模型经过4182次迭代后,它的训练样本、验证样本、测试样本均方误差分别为5.08×10^-6、7.78×10^-6和9.56×10^-6,均小于容许收敛误差限10^-5,而其决定系数亦高达0.981、0.975、0.969,表现出良好的相关性。当利用基于PSO算法的径向基人工神经网络对重催干气脱硫系统能耗进行优化时,经过3198次粒子进化迭代后系统能耗仅为0.0649kg_oe/h,较优化前系统能耗0.0713kg_oe/h降低了8.98%,节能效果显著。     

The Enriched UTAUT Model for the Acceptance of Software Engineering Tools in Academic Education

This article provides an enriched technology acceptance model explaining the impact of both classic and additional variables on software engineering tools acceptance within Information Systems Development courses. Two novel, domain-specific variables were identified (i.e., Professional Training Diffusion and Model Interchange). Statistical verification of the proposed model and study regarding the influence of the variables on students’ intention to use specific tools were conducted—providing users with enhanced means of selecting optimal software for real-life projects.     

Application of the interferometric radar for dynamic tests of corrugated steel plate (CSP) culvert

The paper presents the results of selected experimental tests under dynamic loads, which were conducted on a corrugated steel plate (CSP) culvert. The dynamic loads were caused by the passages of various trains. The displacements and vibration frequencies of the culvert were measured. The microwave interferometric radar and inductive gauge were used for monitoring of displacements of this railway culvert. The conventional inductive gauge was applied to verification of results received by the radar. Conclusions drawn from the tests can be helpful in the measurements of such culverts using the microwave interferometry method.     

Laser patterned carbon–polyethylene mesh electrodes for wound diagnostics

Carbon loaded polyethylene films were selected as the base substrate for a mechanically flexible and conductive sensing material for use wound monitoring technologies. The films were processed using laser ablation of the surface to increase the effective surface area of the electrode and then subject to an oxidative electrochemical etch to improve the electron transfer kinetics. The surface morphology of the resulting films was analysed and the electrode performance in relation to monitoring uric acid, a key wound biomarker, was optimized. A prototype smart bandage was designed, based on interfacing the mesh to a portable potentiostat, and the response to urate and potential interferences assessed.     

On high explosive launching of projectiles for shock physics experiments

The hydrodynamic operation of the "Forest Flyer" type of explosive launching system for shock physics projectiles was investigated in detail using one and two dimensional continuum dynamics simulations. The simulations were numerically converged and insensitive to uncertainties in the material properties; they reproduced the speed of the projectile and the shape of its rear surface. The most commonly used variant, with an Al alloy case, was predicted to produce a slightly curved projectile, subjected to some shock heating and likely exhibiting some porosity from tensile damage. The curvature is caused by a shock reflected from the case; tensile damage is caused by the interaction of the Taylor wave pressure profile from the detonation wave with the free surface of the projectile. The simulations gave only an indication of tensile damage in the projectile, as damage is not understood well enough for predictions in this loading regime. The flatness can be improved by using a case of lower shock impedance, such as polymethyl methacrylate. High-impedance cases, including Al alloys but with denser materials improving the launching efficiency, can be used if designed according to the physics of oblique shock reflection, which indicates an appropriate case taper for any combination of explosive and case material. The tensile stress induced in the projectile depends on the relative thickness of the explosive, expansion gap, and projectile. The thinner the projectile with respect to the explosive, the smaller the tensile stress. Thus if the explosive is initiated with a plane wave lens, the tensile stress is lower than that for initiation with multiple detonators over a plane. The previous plane wave lens designs did, however, induce a tensile stress close to the spall strength of the projectile. The tensile stress can be reduced by changes in the component thicknesses. Experiments verifying the operation of explosively launched projectiles should attempt to measure porosity induced in the projectile: arrival time measurements are likely to be insensitive to porous regions caused by damaged or recollected material.     

Thermodynamic Calculations and Phase Stabilities in the Y-Si-C-O System

A thermodynamic computer dataset for the Y-Si-C-O system was used for calculations of multicomponent, multiphase reactions. The phase reactions of yttrium silicate coatings for the oxidation protection of C/SiC-based composites were analyzed. They were simulated as a function of the temperature and other environmental conditions. To illustrate the high temperature behavior of the coatings, isothermal sections, isopleths, pseudo-binary and -ternary diagrams, phase fraction diagrams, volatility diagrams and potential phase diagrams are presented. Additionally to the thermodynamic aspects, mass balance criteria were taken into account for the analysis of the active/passive oxidation in the coating system. This article was presented at the MultiComponent Alloy Thermodynamics Symposium sponsored by the Alloy Phase Committee of the joint EMPMD/SMD of The Minerals, Metals, and Materials Society (TMS), held in San Antonio, Texas, March 12–16, 2006, to honor the 2006 William Hume-Rothery Award recipient, Professor W. Alan Oates of the University of Salford, UK. The symposium was organized by Y. Austin Chang of the University of Wisconsin, Madison, WI, Patrice Turchi of the Lawrence Livermore National Laboratory, Livermore, CA, and Rainer Schmid-Fetzer of the Technische Universitat Clausthal, Clauthal-Zellerfeld, Germany.     

Effects of high hydrostatic pressure and varying concentrations of sodium nitrite from traditional and vegetable-based sources on the growth of Listeria monocytogenes on ready-to-eat (RTE) sliced ham

The objective of this study was to determine the effect the source of added nitrite and high hydrostatic pressure (HHP) had on the growth of Listeria monocytogenes on ready-to-eat (RTE) sliced ham. Use of 600 MPa HHP for 3 min resulted in an immediate 3.9–4.3 log CFU/g reduction in L. monocytogenes numbers, while use of 400 MPa HHP (3 min) provided less than 1 log CFU/g reduction. With the 600 MPa HHP treatment, sliced ham with a conventional concentration of sodium nitrite (200 ppm) was not different in L. monocytogenes growth from use with 50 or 100 ppm of sodium nitrite in pre-converted celery powder. Instrumental color values as well as residual nitrite and residual nitrate concentrations for cured (sodium nitrite and nitrite from celery powder) and uncured ham formulations are discussed.     

Chemical Composition and Temperature Influence on the Rheological Behaviour of Honeys

The purpose of this work was to examine the viscoelastic properties of Spanish honeys with various sugar contents [fructose (32–42 g/100 g honey), glucose (24–35 g/100 g honey), sucrose (0.0–3.4 g/100 g honey)]; concentrations (79–83 °Brix), and moisture levels (16–19 g/100 g honey) at different temperatures (5, 10, 15, 20, 25, 30, and 40°C). Honey showed Newtonian behaviour, presenting a highly viscous part (loss modulus was much greater than the elastic modulus). The loss modulus (G″) and viscosity increased with moisture content and a decrease with temperature. Exponential and power law models were applied to fit loss modulus and viscosity data. Polynomial models were proposed to describe the combined effect of temperature, fructose, glucose, sucrose content, other sugars, non-sugar substance, and moisture content.     

The effect of high hydrostatic pressure,sodium nitrite and salt concentration on the growth of Listeria monocytogenes on RTE ham and turkey

Growth of Listeria monocytogenes was evaluated for up to 182 days after inoculation on ready-to-eat (RTE) sliced ham and turkey breast formulated with sodium nitrite (0 or 200 ppm), sodium chloride (1.8% or 2.4%), and treated (no treatment or 600 MPa) with high hydrostatic pressure (HHP). HHP at 600 MPa for 3 min resulted in a 3.85–4.35 log CFU/g reduction in L. monocytogenes. With formulations at similar proximate analyses, one of the evaluation days (day 21) without HHP showed significantly greater growth of L. monocytogenes in ham than in turkey breast, but there were no significant differences on other evaluation days or with HHP. There were no differences in growth of L. monocytogenes due to sodium chloride level. Sodium nitrite provided a small, but significant inhibition of L. monocytogenes without HHP, but addition of sodium nitrite did not significantly affect growth of L. monocytogenes with use of HHP.