Silver Nanoparticles Mediate Differential Responses in Keratinocytes and Fibroblasts during Skin Wound Healing

With advances in nanotechnology, pure silver has been recently engineered into nanometer‐sized particles (diameter <100 nm) for use in the treatment of wounds. In conjunction with other studies, we previously demonstrated that the topical application of silver nanoparticles (AgNPs) can promote wound healing through the modulation of cytokines. Nonetheless, the question as to whether AgNPs can affect various skin cell types—keratinocytes and fibroblasts—during the wound‐healing process still remains. Therefore, the aim of this study was to focus on the cellular response and events of dermal contraction and epidermal re‐epithelialization during wound healing under the influence of AgNPs; for this we used a full‐thickness excisional wound model in mice. The wounds were treated with either AgNPs or control with silver sulfadiazine, and the proliferation and biological events of keratinocytes and fibroblasts during healing were studied. Our results confirm that AgNPs can increase the rate of wound closure. On one hand, this was achieved through the promotion of proliferation and migration of keratinocytes. On the other hand, AgNPs can drive the differentiation of fibroblasts into myofibroblasts, thereby promoting wound contraction. These findings further extend our current knowledge of AgNPs in biological and cellular events and also have significant implications for the treatment of wounds in the clinical setting.     

Microwave-assisted beneficiation of recycled concrete aggregates

The presence of mortar has been reported as the main factor causing the lower quality of recycled concrete aggregates (RCA) when compared to natural aggregates (NA). A novel microwave-assisted technique to increase the quality of RCA by partially removing the mortar adhering to RCA particles and breaking up the lumps of mortar present in RCA is introduced in this paper. The technique takes advantage of the difference in the electromagnetic properties of the adhering mortar and natural aggregates to generate high thermal stresses within the mortar, especially at the interface with the embedded natural aggregates, to cause delamination. The stresses generated also result in the breaking up of the lumps of mortar into smaller pieces. The results of an experimental study conducted to investigate the capability of the microwave-assisted RCA beneficiation technique and to compare its efficiency with other beneficiation methods proposed in available literature are presented. Moreover, the effects of incorporating various amounts of un-treated and microwave-treated coarse RCA on the mechanical properties of concrete are investigated. The temperature distribution and stresses developed in RCA when subjected to microwave heating during the beneficiation process are numerically calculated for a better understanding of the processes involved.     

液化石油气混空气的新技术

介绍新型液化石油气-空气混合器（AFC混合器）的原理及优点。     

The effect of contact torques on porosity of cohesive powders

The porosity of uniaxially compacted cohesive powders depends on the applied stress (including gravity). The case, where these stresses are weak, is considered. The compaction results in a porosity which is a function of sliding, rolling and torsion friction. By contact dynamics simulations it is shown that the influences of contact torques (static rolling and torsion friction) on the porosity are significant and approximately additive. The relevance for nano-powder pressure sintering is discussed.     

Effects of the temperature of hot isostatic pressing treatment on Cr–Si targets

Commercial as-hp (hot pressing) treated Cr–Si targets are used throughout this study, with three different compositions: Cr20–Si80, Cr35–Si65 and Cr50–Si50. To evaluate the effects of microstructure and properties of as-hp treated Cr–Si targets by hot isostatic pressing (HIP) SEM, XRD and porosity inspections were performed. The experimental results showed that the 1373 K, 1750 MPa, 4 h HIP treated with three different Cr–Si targets had suppressed porosities successfully. The most efficient was Cr50–Si50 target subjected to HIP treatment. Porosity decreased about 60% after HIP treatment, and both the nitrogen and oxygen concentrations of the targets were slightly increased after HIP treatment. This was especially true for the single silicon in Cr–Si targets such as Cr20–Si80 and Cr35–Si65. The aim of this paper is to discuss these methods and finding suitable temperatures for the HIP for Cr–Si targets.     

Fourier Transform Near-Infrared Spectroscopy to Predict the Gross Energy Content of Food Grade Legumes

The feasibility of Fourier transform near-infrared reflectance spectroscopy (FT-NIRS) for determining gross energy content in different food legumes has been investigated. Eighty food-grade legume samples were obtained from different retailers and local markets in Hungary and they included 42 common beans (Phaseolus vulgaris L.), 20 peas (Pisum sativum L.), 10 lentils (Lens culinaris L.), and 8 soya beans (Glycine max L.) both as full fat food and defatted. The samples were analyzed by an adiabatic bomb calorimeter and then scanned in a Bruker MPA FT-NIR Analyzer (800–2,500 nm). Two algorithms for spectral selection of calibration and validation samples, which represent variability encountered in the full population, were tested. Partial least squares regression were developed for the prediction of gross energy using four different spectral preprocessing methods (first and second derivative alone and combined with standard normal variation and multiplicative scatter correction). The results show that first derivative produced the most accurate results with very high coefficient of determinations in validation (<93 %) and with very low standard errors of validation (<0.025 kcal/g) as compared to the standard error of the reference method (0.204 kcal/g).     

Introduction

A good formwork system enables speedy completion of the concrete structure, following which other subsequent trades can be started. However, the current intuitive judgment approach in the selection of formwork systems cannot assure an optimal and consistent result. Artificial neural networks may improve the selection process. Formwork represents a significant part of the cost of concrete structure construction. Most subsequent trades including internal finishing and external cladding depend on the completion of the building structure. A suitable formwork system is thus crucial for maintaining the smooth flow of the various trades and a proper working sequence of various work activities. Based on data collected from a previous study, it is clear that the key factors affecting the selection of a relevant formwork system include building height and structural system, concrete finish, site conditions, availability of equipment and building shape. Neural network models are developed for the selection of vertical formwork systems using the architecture of the probabilistic neural network (PNN) model. A case study verifies the validity of this approach.     

Analysis of directional factors in milling: importance of multi-frequency calculation and of the inclusion of the effect of the helix angle

The concept of directional factor for chatter stability analysis has been used from a long time ago. The analysis of its evolution for different feed directions in milling processes provides a good way of selecting the best cutting conditions. For very stable cutting directions, corresponding to very low directional factors, the single frequency analysis gives unacceptable results and multi-frequency, or alternative solutions as semi-discretisation must be used. It is found also that the period doubling lobes extend at both sides of the tooth pass frequency equivalent to twice the natural frequency. In these cases, helix angle has a very important effect on the stability. For end milling processes, where the mill axial pitch can be of the order of the stable limit depth of cut, a very stable situation is found except in those areas corresponding to period doubling, where instability islands are found. Besides, a graphical construction for accurate estimation of the stable limit depth of cut and starting rotational speed of the period doubling lobes is proposed.     

Application of Delphi method in selection of procurement systems for construction projects

A number of procurement selection systems have been developed over the last decade. The use of multi-attribute decision analysis has been considered the foremost technique for examining client needs and the weightings of preferences from experts for each procurement system in the most objective way available. However, the major difficulty of these selection models lies in the lack of consensus among the experts on the utility factor of the selection criteria. To overcome these deficiencies, a Delphi technique was adopted to develop a multi-attribute model. Four rounds of Delphi surveys were conducted. A statistically significant consensus on the weighting of the utility factors for each procurement system was obtained from eight experts. The results vividly reveal that the Delphi method is a powerful and appropriate technique for deriving objective opinions in a rather subjective area such as the multi-attribute model for the selection of procurement system.