Controlling the aggregation propensity and thereby digestibility of allergens by Maillardation as illustrated for cod fish parvalbumin

The aggregation propensity of heat-treated codfish parvalbumin is investigated upon Maillardation of the protein under food-relevant conditions. About twelve of the fourteen lysine residues had reacted with glucose under these conditions. It is shown using circular dichroism and fluorescence that extensive coupling of glucose moieties on the protein surface does not affect the secondary and tertiary structural fold nor severely impair calcium-binding under ambient conditions. The glucosylated protein has a 3 °C higher denaturation temperature, while the free energy change involved with denaturation is reduced by 5-10%. It is shown by establishing insight in the change in heat capacity involved in the denaturation process that glucosylation of the protein is likely to result in a lower exposed hydrophobicity in the unfolded state. Aggregation kinetics, as monitored using light scattering techniques, shows that this lower exposed hydrophobicity of the denatured state slows down the aggregation process, while the shape and size of formed aggregates are comparable to those formed by non-glucosylated protein. This lower aggregation propensity allows a significantly faster digestion of heat-treated materials by pepsin. This work demonstrates that (pre-)processing of ingredients containing potential allergens, like cod fish parvalbumin, using food-relevant conditions may provide an effective tool to minimize risks of provoked allergic responses during food consumption.     

Oxidative Dissolution of Biogenic Uraninite in Groundwater at Old Rifle, CO

Reductive bioremediation is currently being explored as a possible strategy for uranium-contaminated aquifers such as the Old Rifle site (Colorado). The stability of U(IV) phases under oxidizing conditions is key to the performance of this procedure. An in situ method was developed to study oxidative dissolution of biogenic uraninite (UO?), a desirable U(VI) bioreduction product, in the Old Rifle, CO, aquifer under different variable oxygen conditions. Overall uranium loss rates were 50-100 times slower than laboratory rates. After accounting for molecular diffusion through the sample holders, a reactive transport model using laboratory dissolution rates was able to predict overall uranium loss. The presence of biomass further retarded diffusion and oxidation rates. These results confirm the importance of diffusion in controlling in-aquifer U(IV) oxidation rates. Upon retrieval, uraninite was found to be free of U(VI), indicating dissolution occurred via oxidation and removal of surface atoms. Interaction of groundwater solutes such as Ca2? or silicate with uraninite surfaces also may retard in-aquifer U loss rates. These results indicate that the prolonged stability of U(IV) species in aquifers is strongly influenced by permeability, the presence of bacterial cells and cell exudates, and groundwater geochemistry.     

Performance analysis and impedance spectral signatures of high temperature PBI–phosphoric acid gel membrane fuel cells

Polarization curves, i.e., dc performance, and impedance spectral signatures of polybenzimidazole (PBI)–phosphoric acid (H₃PO₄) membrane fuel cells are obtained in the temperature range of 160–180 °C, in an effort to investigate the effect of temperature, anode humidification, various cathode stoichs, and use of oxygen versus air. Thus, in situ electrochemical impedance spectroscopy (EIS) was used to obtain various resistances, ohmic as well as charge-transfer resistances, under these conditions. The results obtained show that PBI–H₃PO₄ gel membrane fuel cells exhibit very good performance in the temperature range of 160–180 °C with an ohmic resistance similar to Nafion. Mass transfer limitations were determined by comparing performance polarization curves with air and oxygen along with EIS. Further EIS was also used to obtain signatures during fuel starvation, and electrical shorting across the cell.     

制作用于RF部件的快周转PCB

采用低成本PCB(印刷电路板),几个小时内就可以很容易用几乎任何CAD软件(甚至免费软件)设计出一块电路板。只需两天时间,在自己的案头就能完成原型板。很多软件包都有不错的设计规则,大多数PCB制造商可以制作出低至0.006英寸线宽和线距。     

复杂功能超高层建筑的结构设计挑战

0引言总部位于美国纽约的宋腾添玛沙帝工程顾问有限公司(Thornton Tomasetti Inc.,简称TT),是一个专长大型复杂结构设计的公司,其凭借专业实力,参与了世界前20个超高层建筑中近一半项目的结构设计,包括已建成的中国台湾台北市的世界金融中心(即台北101)、马来西亚吉隆坡的双子石油大厦、上海的恒隆广场和正在建设中的上海中心、芝加哥螺旋塔、     

Microstructure and properties of diffusion bonded Ti-6Al-4V parts using brazing-assisted hot isostatic pressing

Ti-6Al-4V couples have been diffusion bonded by hot isostatic pressing (HIPping) after vacuum brazing was used to seal the periphery of the bonding samples so that no encapsulation was required during HIPping. Analytical scanning electron microscopy was used to assess the microstructure of the HIPped interface and tensile and fatigue properties of bonded samples were compared with those of the bulk starting material. The tensile properties of the bonds were shown to be comparable with those of the bulk material, but the fatigue life was slightly downgraded. The fatigue fractures were initiated by inclusions on the bonding interface, caused by contamination before bonding, but the fatigue cracks did not propagate along the bonding interface indicating a strong bond. It is concluded that this technique of vacuum brazing plus HIPping could be used for encapsulation-free HIPping to produce complex-shaped components.     

Impact of finite receiver-aperture size in a non-line-of-sight single-scatter propagation model

In this paper, a single-scatter propagation model is developed that expands the classical model by considering a finite receiver-aperture size for non-line-of-sight communication. The expanded model overcomes some of the difficulties with the classical model, most notably, inaccuracies in scenarios with short range and low elevation angle where significant scattering takes place near the receiver. The developed model does not approximate the receiver aperture as a point, but uses its dimensions for both field-of-view and solid-angle computations. To verify the model, a Monte Carlo simulation of photon transport in a turbid medium is applied. Simulation results for temporal responses and path losses are presented at a wavelength of 260 nm that lies in the solar-blind ultraviolet region.     

Dynamics of control in construction project teams

Control is pervasive in construction project environments. The management of projects through various planning and control tools has therefore been described essentially as rebureaucratization which increases control over individuals, teams and organizations through ideologies of efficiency and performativity. Yet certain characteristics of the project setting make it an ideal climate for the empowerment of individuals and teams. The manifestations of control in five construction project management teams involved in two ongoing construction projects in Hong Kong are examined. The interpretive and exploratory focus of the study favoured the use of a qualitative research design and the case study approach in particular. Control is viewed as all devices and systems employed to ensure that acts, behaviours, outcomes and decisions of individuals, teams and organizations are consistent with meeting organizational or project goals, objectives and strategies. The findings indicate that a portfolio of control modes is implemented in project teams comprising both formal (i.e. behaviour‐ and outcome‐based) and informal (i.e. clan‐ and self‐based) control mechanisms which are not necessarily incompatible. While formal control remains the primary control mode, a portfolio of control appears necessary to augment the inadequacies of formal control due to the evolving nature of the project environment.     

Behaviour-based safety management in Hong Kong's construction industry: the results of a field study

Hong Kong's construction industry has had a poor site safety record for over a decade. Behaviour-based methods of safety management (BSM) have proved successful in other industries and in other countries. Hence, this study aimed to test the effectiveness of BSM by applying goal-setting and feedback interventions to specific areas of safety performance on Hong Kong Housing Authority construction sites. Using a within-group experimental design and with the use of a proportional rating safety measurement instrument, data were collected on the effectiveness of BSM on Hong Kong sites. The data were recognized as time series data; this has been a serious methodological oversight in much previous research. The data were analysed using autoregressive moving averages models, and the results were mixed in that a significant improvement in safety performance occurred in the housekeeping category of intervention but no improvement was observed in the access to heights and bamboo scaffolding categories. Based on these results a goal setting/expectancy theory model of site safety improvement has been synthesized, and the lack of provision of an adequate safety infrastructure has been identified as a serious impediment to improvement.