采用铸造-倾析-铸造技术制备A390/A356铝合金功能梯度复合材料时过热和凝固层厚度对其界面接合的影响（英文）

铸造-倾析-铸造技术是近年来发展起来的一种制备功能梯度材料的新方法。采用这种方法制备在径向具有梯度功能的圆柱形试样,其外表层为具有高耐磨性的A390铝合金,芯部为具有较高韧性和加工性能的A356铝合金。研究芯部熔体在不同过热温度(750,820和860°C)和表层在不同倾析时间(25,35和45 s)下的A390/A356合金界面接合情况。采用光学显微镜和扫描电镜对界面进行表征,对界面区的显微硬度进行测量。结果表明,在过热温度为860°C,倾析时间为35 s的条件下,可以获得一宽度约为500μm的接合良好的界面层。比较了试样表面层和芯部的耐磨性能。     

采用铸造-倾析-铸造技术制备A390／A356铝合金功能梯度复合材料时过热和凝固层厚度对其界面接合的影响

铸造-倾析-铸造技术是近年来发展起来的一种制备功能梯度材料的新方法。采用这种方法制备在径向具有梯度功能的圆柱形试样,其外表层为具有高耐磨性的 A390铝合金,芯部为具有较高韧性和加工性能的 A356铝合金。研究芯部熔体在不同过热温度（750,820和860℃）和表层在不同倾析时间（25,35和45 s）下的A390/A356合金界面接合情况。采用光学显微镜和扫描电镜对界面进行表征,对界面区的显微硬度进行测量。结果表明,在过热温度为860℃,倾析时间为35 s的条件下,可以获得一宽度约为500μm的接合良好的界面层。比较了试样表面层和芯部的耐磨性能。     

Anti-proliferative effects of a small molecule inhibitor of CDK AT7519 on chronic myeloid leukemia (CML) cells through halting the transition of cells from G2/M phase of the cell cycle

Pathogenesis of chronic myeloid leukemia (CML) has mostly been studied with regard to the oncogenic role of BCR/ABL fusion; however, recent disclosures have declared that the challenges with the treatment of CML patients would not be resolved until the role of other aberrancies is ignored. Given the involvement of cyclin-dependent kinases (CDKs) in the pathogenesis of CML, the present study aimed to investigate the effects of a multi-CDK inhibitor AT7519 on BCR/ABL-harboring CML-derived K562 cells. Our results showed that AT7519 effectively reduced the survival of K562 and induced its anti-proliferative effect through the induction of G2/M arrest due to elevated p21 and p27. The resulting data also revealed that either direct or indirect suppression of c-Myc using specific c-Myc inhibitor 10058-F4 and selective PI3K inhibitor CAL-101 resulted in a superior cytotoxicity, suggesting that the activation of PI3K pathway could attenuate antileukemic effects of the inhibitor, at least partly, through a c-Mycdependent mechanism. To the best of our knowledge, to date, no study has addressed the effect of autophagy on CML cell response to AT7519, and, herein, we proposed for the first time that the suppression of autophagy boosted AT7519 cytotoxicity against K562. Overall, we suggested that selective CDK inhibitor AT7519 exerted antileukemic effect against CML cells and propose a novel therapeutic application for the inhibitor either as a single agent or in combination with c-Myc and/or PI3K inhibitors.     

Temperature distribution and efficiency assessment of different PVT water collector designs

The aim of this work was to study different hybrid photovoltaic-thermal (PVT) collectors. Numerical simulation of the collectors was carried out using a 3-dimensional computational fluid dynamic (CFD) model. A set of experiments was conducted using a box-type PVT collector to validate the obtained computed data. Simulation results for water outlet temperature, especially at the lower flow rates, were closer to the measured data compared with average module surface temperature. Based on the simulation results, the spiral flow designs of heat exchanger provided the most uniform temperature distribution for module surface and the highest temperature gradient was observed with the direct flow designs. A hot zone was generated on the module surface of the direct flow box-type collector and the results indicated that the hot zone was considerably declined using cross-fins inside the box-type heat exchanger. The highest heat transfer to the ambient occurred with the spiral flow design and the box type heat exchanger presented a relatively low heat losses. The cross-fined box type and the spiral flow designs of the PVT collector had the highest electrical efficiencies at the different test conditions.     

Study of Current Sheath Velocity and Its Distribution Using Tridimensional Magnetic Probe in Sahand Plasma Focus

The current sheath velocity in 0.25 Torr gas pressure of Filippov type plasma focus is studied experimentally.By using two tridimensional magnetic probes on top of the anode surface,the current sheath velocity is measured for argon,oxygen and nitrogen.Additionally,the effect of charging voltage on the current sheath velocity is studied in both axial and radial phases.We found that,the maximum current sheath velocities at both radial and axial phases are respectively 4.33 ± 0.28(cm/μs) and 3.92 ± 0.75(cm/μs) with argon as the working gas at 17 kV.Also,the minimum values of current sheath velocity are 1.48 ± 0.15(cm/μs) at the radial phase and 1.14 ± 0.09(cm/μs) at the axial phase with oxygen at 12 kV.The current sheath velocity at the radial phase is higher than that at the axial phase for all gases and voltages.In this study,variation of the full width half maximum(FWHM) of magnetic probe signals with voltage is investigated for different gases at radial and axial phases.     

A New Insight into Energy Distribution of Electrons in Fuel-Rod Gap in VVER-1000 Nuclear Reactor

In order to calculate the electron energy distribution in the fuel rod gap of a VVER-1000 nuclear reactor,the Fokker-Planck equation(FPE)governing the non-equilibrium behavior of electrons passing through the fuel-rod gap as an absorber has been solved in this paper.Besides,the Monte Carlo Geant4 code was employed to simulate the electron migration in the fuel-rod gap and the energy distribution of electrons was found.As for the results,the accuracy of the FPE was compared to the Geant4 code outcomes and a satisfactory agreement was found.Also,different percentage of the volatile and noble gas fission fragments produced in fission reactions in fuel rod,i.e.Krypton,Xenon,Iodine,Bromine,Rubidium and Cesium were employed so as to investigate their effects on the electrons' energy distribution.The present results show that most of the electrons in the fuel rod's gap were within the thermal energy limitation and the tail of the electron energy distribution was far from a Maxwellian distribution.The interesting outcome was that the electron energy distribution is slightly increased due to the accumulation of fission fragments in the gap.It should be noted that solving the FPE for the energy straggling electrons that are penetrating into the fuel-rod gap in the VVER-1000 nuclear reactor has been carried out for the first time using an analytical approach.     

Calorimetric and spectroscopic investigations of β-lactoglobulin upon interaction with copper ion

The effect of copper(II) ions (Cu(+2)) on the structure of β-lactoglobulin (β-lg) was investigated spectroscopically using UV-visible, fluorescence and circular dichroism (CD) and calorimetrically using isothermal titration calorimetry (ITC), at different temperatures. Results of the UV-visible studies showed that adding Cu(+2) to β-lg solution caused increasing turbidity, indicative of protein aggregation. It was noticeable that the rate of increasing turbidity was directly proportional to increasing temperature. The far-UV CD studies displayed that the Cu(+2) cannot induce any significant changes in the secondary structures of β-lg at different temperatures. Also, the ITC data indicated that the binding process of Cu(+2) to β-lg is mainly entropically driven. The results highlight that copper ions cause the tertiary structure of β-lg to change and induce a slightly open structure leading to the formation of supramolecular aggregates in β-lg which may result in the reduced allergenicity of β-lg and its increased use in industrial applications.     

Efficient Window Block Retrieval in Quadtree-Based Spatial Databases

An algorithm is presented to answer window queries in a quadtree-based spatial database environment by retrieving all of the quadtree blocks in the underlying spatial database that cover the quadtree blocks that comprise the window. It works by decomposing the window operation into sub-operations over smaller window partitions. These partitions are the quadtree blocks corresponding to the window. Although a block b in the underlying spatial database may cover several of the smaller window partitions, b is only retrieved once rather than multiple times. This is achieved by using an auxiliary main memory data structure called the active border which requires O(n) additional storage for a window query of size n×n. As a result, the algorithm generates an optimal number of disk I/O requests to answer a window query (i.e., one request per covering quadtree block). A proof of correctness and an analysis of the algorithm's execution time and space requirements are given, as are some experimental results.     

Characterization of Cranberry Benzoates and Their Antimicrobial Properties

Vacciniin (6-benzoyl-D-glucose) and benzoic acid were the only benzoates detected in extracts of the Stevens cultivar of cranberry. Vacciniin represents 75% of the total and was not inhibitory to the yeasts, Gram positive, or Gram negative bacteria tested.