Establishment of microglial cell cultures derived from postmortem human adult brain tissue: immunophenotypical and functional characterization

Cell cultures have become an integral part of the daily routine in most biological research laboratories. Because they are very dynamic and highly accessible, cell cultures permit direct experimental manipulations where cause-effect relations can be more definitely assayed. We have developed cultures of microglial cells from rapid autopsies (range 3-10 hours) of nondemented elderly patients and Alzheimer's disease patients. Cultures were derived from the subcortical white matter, corpus callosum, and frontal, temporal, and occipital cortex. The adherent microglial cells were immunoreactive for CD68, CD45, CD11c, and major histocompatibility complex (MHC) class II markers, and were not immunoreactive for astrocyte or oligodendrocyte markers. In addition, some functional characteristics of the isolated microglial cells were also studied. Upon stimulation with lipopolysaccharide (LPS), microglial cells secreted pro- and antiinflammatory mediators, i.e., interleukin- (IL)-6, prostaglandin E2 (PGE2), and IL-10, indicating the functional capacity of cultured microglia.     

Alveolar macrophage-T cell interactions during Th1-type sarcoid inflammation

Sarcoidosis is an immunomediated, multisystem disorder of unknown cause(s) characterized by a heightened Th1 immune response that leads to an uncontrolled granuloma formation at sites of disease activity. The past few years have seen outstanding advances in the understanding of immunological and molecular events involved in the pathogenesis of this disease. The idea is that several cytokines and chemokines, which are secreted at sites of disease activity, participate in granuloma formation. This paper describes recent data that have clarified some of the events that govern the development of the hypersensitivity reaction during sarcoidosis. In particular, we will review recent evidence indicating that a complex relationship exists between the macrophage/lymphocyte cellular axis and the tissue networks of cytokines.     

Interleukin-1β regulates metalloproteinase activity and leptin secretion in a cytotrophoblast model

Implantation is one of the most regulated processes in human reproduction, by endocrine and immunological systems. Cytokines are involved in embryo-maternal communication and an impaired balance could result in pregnancy loss. Here we investigated the effect of interleukin 1-β on the activity of two important metalloproteinases (MMP-2 and MMP-9) that are involved in extracellular matrix remodeling as well as the secretion of leptin, one of the reproductive hormones actively regulating their activity and secretion. We found that IL-1β activates matrix metalloproteinase activity as well as increases leptin secretion. We propose that this interleukin, through the regulation of leptin, in turn activates matrix metalloproteinases which results in an increased cytotrophoblast invasion.     

面向系统功能特性的协同验证方法研究

为了提高芯片设计中功能验证环节的效率,提出了一种对系统的功能特性归类划分、自动选择适合的验证技术的协同验证方法,构建了多种验证技术之间无缝协作的平台。该协同验证方法所依据的策略是：特定的功能特性采用特定的验证技术更有效。因此,利用不同验证技术的互补验证能力,可提高验证效率。协同验证平台的实现是基于从控制数据流图得到的细化模型,该细化模型采用了包括特性分组、变量重排、结构细化等模型优化技术,以提高验证速度。根据在ITC99上的验证,证明了该协同验证方法的有效性和实用性。     

Estimating the functional properties of thin calcium-phosphate coatings on medical implants

Thin calcium-phosphate (CP) coatings were formed on the models of medical products by radio-frequency (RF) magnetron sputtering. Using microscope studies, the coatings were shown to be visually continuous without visible pores and cracks. The functional properties of thin CP coatings were estimated by the method based on the measurement of the disruptive electrical voltage in compliance with GOST (State Standard) 9.302. Thin CP coatings on specimens subjected to sand blasting endured shear loads better in comparison with bending ones.     

铝基复合摩擦材料摩擦磨损性能研究

以S iC颗粒增强的铝基复合材料(S iCp)与GCr15钢配副为对象,与现用的蠕墨铸铁(Compacted graph ite iron)制动盘材料进行对比,应用销-盘式高速摩擦磨损模拟试验,研究摩擦磨损条件对摩擦学特性的影响规律。     

斯密特棱镜偏振特性的Mueller矩阵法分析和检测

斯密特棱镜的偏振像差导致了成像质量的下降,对斯密特棱镜偏振像差的矫正效果的定量检测成为当务之急。Mueller矩阵法不仅可以用于斯密特棱镜偏振特性的分析,而且可以作为斯密特棱镜偏振特性的表征和检测对象。采用双旋转延长器的结构,通过两个四分之一波片的周期变化,对入射光的偏振态进行调制,用傅里叶级数法计算出斯密特棱镜Mueller矩阵元,经分析计算和实验检测,得到其对应两路径的位相延迟差和双向衰减率都明显不相同。用双向衰减率和位相延迟差表征斯密特棱镜的偏振像差,数据直接来自Mueller矩阵,直观、便捷是其最大的特点。     

Cellular and subcellular coherent dynamics,biological functional properties,and system-environment interaction

In this view point paper, we briefly summarize some of the clinical, biochemical and biophysical results obtainedin our research on Relaxation Response. We also qualitatively describe the theoretical biophysical model that could linkthem. Our work points to a unified view of the human biological system activity, joining the dynamics ruling theinteractions and correlations of the microscopic components to the knowledge of their specific individual propertiesin the effort of going beyond a purely atomistic approach.     

Tribological properties of self-lubricating CMC/Al2O3 pairs at high temperature in air

Three different self-lubricating ceramic matrix composites (CMCs) were fabricated by hot-pressed sintering. They are: Al₂O₃-50CaF₂, Al₂O₃-20Ag20CaF₂, and Al₂O₃-10Ag20CaF₂. Tribological tests were performed at temperatures ranging from 20°C to 800°C in air using a pin-on-disk tester. The experimental results show that the addition of the solid lubricants CaF₂ and Ag can evidently reduce the friction coefficients of alumina between 200°C and 650°C but not at room temperature and the wear rate of disks and pins at elevated temperature. The improvements in the friction and wear properties of CMC were due to the formation of a well-covered solid lubricating film. However, breakdown of the lubricating films at 800°C resulted in high friction and wear. This revised version was published online in August 2006 with corrections to the Cover Date.     

Tribological properties of a perfluoropolyether lubricant with 3-phenylpropyl functional group for hard disk media

A new perfluoropolyether lubricant (LUB-A) with a 3-phenylpropyl functional group at both ends of the main chain was designed and synthesized by the authors for use in hard disk media, and its tribological performance was evaluated. Time-of-flight secondary ion mass spectrometry showed that LUB-A film on the disk lost none of its functional groups even after a 672 h exposure at 23 °C and 55% RH, although AM3001 lost 94% of its (3,4-dioxomethylenephenyl)methyl functional groups after the same period of exposure. It was found that cyclotriphosphazene (X-1P) was more than four times more soluble in 2 nm thick LUB-A film than in AM3001 film. The degradation ratio of read-back signals in the seek test was less than 5% over a wide range of X-1P content in LUB-A film and no micro-phase separation was induced, in contrast to AM3001 film that could not keep the degradation ratio at less than 5% without inducing micro-phase separation. LUB-A also showed better migration properties at 80 °C and 3% RH than AM3001. LUB-A was proved to be more chemically stable and to show better tribological performance than the currently popular AM3001 when it was used as a thin film mixed with X-1P.     

Synthesis and properties of cyclotriphosphazene and perfluoropolyether‐based lubricant with polar functional groups

A novel hard disk lubricant IDL2 was synthesised by reacting sodium 4‐((2,2‐dimethyl‐1,3‐dioxolan‐4‐yl)methoxy)phenoate with hexachlorocyclotriphosphazene, followed by treatment with 1H,1H‐perfluoro‐3,6,9‐trioxatridecan‐1‐ol in the presence of sodium hydride and subsequent hydrolysis using sulfuric acid. The chemical structure of IDL2 was confirmed by proton nuclear magnetic resonance (¹H NMR), phosphorus‐31 (³¹P) NMR spectroscopy and mass spectrometer. The thermal property of IDL2 was analysed using thermal gravimetric analysis (TGA) and it shows better thermal stability than two commercial lubricants Z‐DOL and Z‐Tetraol with two and four terminal hydroxy groups, respectively. IDL2 was found to have comparable hydrophobicity to commercial lubricants Z‐DOL, A20H and Z‐Tetraol with water contact angles in the range of 78 – 85°, revealing that IDL2 has analogous surface energy to these commercial lubricants. IDL2 exhibits comparable friction coefficient to A20H and Z‐Tetraol, but much lower than Z‐DOL. More interestingly, it has a much high bonding ratio when compared with commonly used commercial lubricants under the same testing conditions due to the presence of two polar hydroxy groups, which enhance the interaction between lubricant and substrate. These promising properties of IDL2 show that it would be very potential for real application as a hard disk drive lubricant. Copyright © 2016 John Wiley & Sons, Ltd.     

氧化钇颗粒增强铜基复合材料的组织与性能研究

本文以添加0~20%体积分数的Y2O3颗粒增强铜基复合材料为研究对象,利用金相照片,扫描电镜、显微硬度、腐蚀试验等测试技术及实验手段,宏微观结合进行组织与性能分析。结果表明,Y2O3颗粒与基体结合得很致密,它们之间基本上无裂隙存在。随着Y2O3含量的增加,该系列铜基复合材料的多孔率下降,显微硬度值上升幅度较大,强化效果较好,耐腐蚀性也得到提高。     

Application of grey-taguchi method for optimization of dry sliding wear properties of aluminum MMCs

Through a pin-on-disc type wear setup, the dry sliding wear behavior of SiC-reinforced aluminum composites produced using the molten metal mixing method was investigated in this paper. Dry sliding wear tests were carried on SiC-reinforced metal matrix composites (MMCs) and its matrix alloy sliding against a steel counter face. Different contact stresses, reinforcement percentages, sliding distances, and sliding velocities were selected as the control variables, and the responses were selected as the wear volume loss (WVL) and coefficient of friction (COF) to evaluate the dry sliding performance. An L25 orthogonal array was employed for the experimental design. Initially, the optimization of the dry sliding performance of the SiC-reinforced MMCs was performed using grey relational analysis (GRA). Based on the GRA, the optimum level parameters for overall grey relational grade in terms of WVL and COF were identified. Analysis of variance was performed to determine the effect of individual factors on the overall grey relational grade. The results indicated that the sliding velocity was the most effective factor among the control parameters on dry sliding wear, followed by the reinforcement percentage, sliding distance, and contact stress. Finally, the wear surface morphology and wear mechanism of the composites were investigated through scanning electron microscopy.     

B4C颗粒对AZ61蠕变及磨损性能影响的研究

采用机械搅拌法制备B4C/AZ61镁基复合材料,并通过对比AZ61镁合金和B4C/AZ61镁基复合材料的蠕变和磨损试验,分析B4C颗粒对AZ61镁合金蠕变及磨损性能的影响.结果表明:在蠕变性能上,与AZ61镁合金相比,B4C/AZ61镁基复合材料具有较小的初始蠕变量和较小的总蠕变量,进入稳态蠕变阶段的时间和进入稳态蠕变状态时的蠕变速率与AZ61镁合金基本相同;在磨损性能上,B4C颗粒的添加使得AZ61镁合金的抗磨损性能得到明显提升.     

Optimizing the composition and properties of nanostructural coatings for cutting tools on the basis of the electron-density functional

Nanostructural coatings for cutting tools are optimized on the basis of the electron-density functional. Means of modifying the coating composition so as to improve tool performance are outlined.     

Synthesis and evaluation of mechanical and high temperature tribological properties of in-situ Al-TiC composites

In situ Al-TiC (5, 10 and 15 wt%) composites were produced by using a reaction mixture of K₂TiF₆ and graphite powder with molten metal. The effect of ceramic particulate addition on the high temperature sliding wear resistance of the composites was studied. The sliding wear tests were conducted at room temperature, 120 and 200 °C. The wear rate increases with the increase in applied load and decreases with increase in the weight percentage of TiC. Both monolithic and composites were able to withstand thermal softening effects due to the formation of oxidative protective transfer layer.     

Influence of pitch air-blowing and thermal treatment on the microstructure and mechanical properties of carbon/carbon composites

This paper discusses the optimization of pitch properties as a matrix precursor of C/C composites by subjecting the pitches to different pretreatments to promote polymerization of the molecular components of pitch, which could improve carbon yield and density of the resultant carbon materials. Two series of pitches were prepared by air-blowing of impregnating coal-tar pitches at temperatures between 523 and 573 K, and thermal treatment at temperatures between 673 and 703 K, in an inert atmosphere. Effects of pitch treatments on resultant coke texture and porosity were monitored by polarized light microscopy. Unidirectional laminar composites were prepared using the original and treated pitches and commercial PAN-based carbon fibres. Effects of pitch treatments on the main microstructural features of composites are determined by scanning electron microscopy and polarized light microscopy, and related to the mechanical properties of composites. Results show an improvement of the mechanical properties of composites in both series, particularly for pitch treatments at 523 K/air in the air-blown series, and at 698 K–5 h in the thermally treated one.     

Influence of Cr content on tribological properties of Ni3Al matrix high temperature self-lubricating composites

High temperature self-lubricating composites Ni₃Al-BaF₂-CaF₂-Ag-Cr were fabricated by powder metallurgy technique. In this paper the effect of Cr content on tribological properties at a wide temperature range starting from room temperature to 1000 °C was investigated. It was found that Ni₃Al matrix composite with 20 wt% Cr exhibited low friction coefficient of 0.24-0.37 and a wear rate of 0.52-2.32×10⁻⁴ mm³ N⁻¹ m⁻¹. Especially at 800 °C it showed the lowest friction coefficient of 0.24 and a favorable wear rate of 0.71×10⁻⁴ mm³ N⁻¹ m⁻¹. This implied that 20 wt% Cr was the optimal Cr content and its excellent tribological performance could be attributed to the balance between strength and lubricity.     

Improvement of triboengineering properties and noise reduction of tooth gears by cladding functional coatings on working surfaces of interfaced teeth

The results of a study on the technological capabilities of the modification of working profile of the teeth of the gears by nanostructured functionally oriented coating particles formed by the method of cladding by a flexible tool (CFT) and evaluated their impact on the reduction of generated tooth gearing noise. It is established that the efficiency of the technology CFT used for the noise reduction of bevel gear drives of machine tools is largely determined by the rational choice of the donor material composition for the formation of a coating. In some cases, gear teeth made from various materials formed on the working profile can significantly change the general character of the distribution of the frequencies of sound energy reducing the level of noise at one frequency and remaining unchanged or even higher at others. The best results in lower noise level of gearing in the whole spectrum of frequencies provided by the bronze-graphite Br05S20Gr0.5DMO0.5 coating. The decrease in noise at the general level was 2–4 dBA depending on rotation speed and, on a separate spectral component, reaches 6–9 dBA.