A comparison between a time domain and continuous wave small animal optical imaging system

We present a phantom study to evaluate the performance of the eXplore Optix (Advanced Research Technologies-GE Healthcare), the first commercially available time-domain tomography system for small animal fluorescence imaging, and compare its capabilities with the widely used IVIS 200 (Xenogen Corporation-Caliper) continuous wave planar imaging system. The eXplore Optix, based on point-wise illumination and collection scheme, is found to be a log order more sensitive with significantly higher detection depth and spatial resolution as compared with the wide-area illumination IVIS 200 under the conditions tested. A time-resolved detection system allows the eXplore Optix to measure the arrival time distribution of fluorescence photons. This enables fluorescence lifetime measurement, absorption mapping, and estimation of fluorescent inclusion depth, which in turn is used by a reconstruction algorithm to calculate the volumetric distribution of the fluorophore concentration. An increased acquisition time and lack of ability to image multiple animals simultaneously are the main drawbacks of the eXplore Optix as compared with the IVIS 200.     

Wielding the Double-Edged Sword of Inflammation: Building Biomaterial-Based Strategies for Immunomodulation in Ischemic Stroke Treatment

Stroke is a leading cause of disability with no current treatment to regenerate lost brain tissue. Innovative preclinical and clinical trials have attempted to improve stroke recovery by promoting cell survival, downregulating astrogliosis and inflammation, and improving neurogenesis and angiogenesis; however, the complexity of stroke pathophysiology raises many challenges. Previous attempts to grossly inhibit the inflammatory reaction failed to improve stroke outcomes, prompting scientists to explore selective modulation rather than unbiased inhibition. Although experimental studies involving immunomodulation are successful, strategies have largely failed in the clinic. Some of these approaches are hindered by poor delivery efficiency or cell survival, challenges that could be at least partially overcome using biomaterials. Biomaterials may enhance immunomodulatory processes by improving drug and cell delivery to the injured tissue. Furthermore, the materials themselves can support healing and may be designed to act as immunomodulators, thereby contributing to tissue regeneration and endogenous repair processes. Described here are novel biomaterial-based strategies to modulate the immune response after ischemic stroke, with an emphasis on extracellular matrix mimetics and hydrogels for local delivery of drugs and cells. Finally, a future perspective is described, highlighting the potential of these therapies to achieve clinical translation and improve patients’ functional repair.     

Variation of microstructure and mechanical property of slurry die cast Al-Si-Mg-Fe alloy

Semi-solid metal processing technologies have been intensively studied in recent years. Gas Induced Semi-Solid (GISS) is a slurry preparation technique for producing non-dendritic or globular structures for cast alloys. In the present study, GISS technique was used in conjunction with conventional die cast process for casting Al–Si–Mg–Fe alloy. The shape of die cast specimen was designed as a simple flat plate. The variation of microstructures and tensile properties of specimens from different locations of cast plates was studied. The results show that the specimens from bottom location, near the gate section and the middle location of cast plates are stronger and more ductility than those from the top location. The microstructural examination reveals that the specimens from top location of cast plates contain more defects, such as shrinkage pores than those from the other locations. These defects are resulted in lower strength and ductility of the cast product.     

考虑物理-信息虚拟连接的电力信息物理融合系统的脆弱性评估

不断发展的自动化与信息技术的广泛应用明显提高了现代电力系统的运行水平,电力信息系统与电力物理系统的融合也逐步广泛和深入,从而进化为电力信息物理融合系统(CPPS)。在CPPS中,信息设备的故障会影响物理系统的安全可靠运行,而外部对物理与信息元件的攻击则可能导致停电事故。在此背景下,为了分析物理元件与信息元件的交互影响,将CPPS抽象模拟为物理节点、物理-物理连接、信息节点、信息-信息连接与信息-物理连接5类元素,并在此基础上评估信息系统受损对物理系统运行的影响。在博弈论的框架下构建了双层数学规划模型分别对物理与信息环节进行了防御资源分配,用于量化存在假想攻击下系统中各环节的重要程度。以修改的IEEE 14节点系统为例进行了仿真计算,结果验证了所提方法的可行性与有效性。     

A decision-making support system module for project manager selection according to past performance

This paper proposes a decision-making support system (DMSS) module for selecting project managers and demonstrates its implementation. The selection of a new project manager is based mainly on the past performance of potential managers, for example, on the relative performance evaluations they have received on projects managed by them in the past. Past projects are ranked in accordance with a ranking method. Project managers are ordered according to past project rank. The difference in quality between the past performance of the candidates is statistically examined using the Mann–Whitney–Wilcoxon U test. This enables the establishment of a subgroup of one or more preferred candidates, where the significance level of the statistical test has an impact on the subgroup size. The final candidate may be selected from this subgroup according to personal qualifications and suitability for the specific project. We demonstrated the use of such a DMSS module by an Israeli information technology company as part of their process to select a project manager. A ranking method within the Data Envelopment Analysis context (the Cross-Efficient method) was implemented with three inputs and four outputs selected for the project ranking.     

Evaluation of Surface Cracks Using Magnetic Flux Leakage Testing

The magnetic field distribution characteristics of surface cracks with various widths are discussed based on finite element (FEM) results.The crack depth was 0.20 mm ,the width range was from 0.02 to 1.00mm .The results showed that crack width and lift-off( the distance between surface and sensor )will influence singals.Discussed in this paper is the influence of various lift-off parameters on the peak to peak values of the normal component in magnetic flux leakage testing .The effects can be applied to evaluate surface breaking cracks of different widths and depths.An idea is presented to smooth narrow, sharp crack tips using alternating current (AC) field magnetization.     

对影响计量泵精度和耐磨性因素的理论研究

对灌注机关键部件——计量泵进行理论分析,借助C++bulider开发的计算工具研究了计量配合尺寸、形状及工作条件对其精度和寿命的影响;着重分析对中效应对提高精度和减小磨损的影响。为研究计量泵提供了模型或框架;为设计模拟实验提供理论基础,并指导参数的选择。     

Microwave‐Assisted Synthesis of Nanocrystalline MgO and Its Use as a Bacteriocide

Nanocrystalline particles of MgO were synthesized using microwave radiation in an ethylene glycol solution. The antibacterial activities of the MgO nanoparticles were tested by treating Escherichia coli (Gram negative) and Staphylococcus aureus (Gram positive) cultures with 1 mg mL^–1 of the nanoparticles. We have examined the importance of the size effect, pH, and the form of the active MgO species as a bactericidal agent. A clear size dependence of the nanoparticles is observed where the amount of eradicated bacteria was strongly dependent on the particle size.     

混凝土中氯离子迁移特征的表征

混凝土中氯离子的迁移是个非常复杂的过程.一般将测量和计算硬化水泥浆体和混凝土中氯离子的迁移的方法分为非稳态和稳态两大类.对混凝土中氯离子迁移的测试方法进行了评述,并分析了其优点和缺点.北欧标准NTBuild492是目前非稳态条件下快速测试氯离子扩散性最好的方法,但实际的氯离子浓度分布与其计算公式用的模型的模拟仍存在一定的差异.北欧标准NT Build 355是目前稳态条件下快速测试氯离子扩散性最好的方法,但理论基础过于简化.尽管ASTM C1202或AASHTO T277在世界上被广泛应用,但实际上它是一个测量混凝土电导的方法,它可用于混凝土的质量控制,如其结果没有与混凝土的氯离子渗透性试验结果建立相关性时,不能直接用于评价混凝土的氯离子渗透性.