GM-CSF及CBS在肝损伤中的研究进展

肝损伤(liver injury)是指基因遗传或外部原因诱发的肝脏功能异常性疾病.临床表现为食欲不振、乏力、恶心、黄疸、疲乏等,严重者将出现肝功能衰竭,致死风险极高.在交通肇事、暴力犯罪及意外事件中,肝由于体积大、位置固定、质地脆弱、血运丰富等原因,往往是最容易发生损伤的器官之一,肝损伤后的死亡率可高达10.5％～25％[1].随着时间的变化,肝损伤的程度、病理改变、GM-CSF等相关细胞因子及CBS等相关酶的表达水平也会进一步变化.肝损伤后,由于肝内部环境稳态的破坏,器官的状态、结构、各种蛋白的转录水平、蛋白及细胞因子的表达变化水平也会发生一定程度的改变.因此定性定量地分析这些变化,找到时间相关性强的特异性指标,对于指导法医学的实践具有重要的作用.因此在法医学鉴定中,通过肝脏损伤及病变程度的改变,明确肝损伤病变与死亡时间的关系有利于判断事件或案件性质,并有助于进一步对责任方的认定.     

Non-keyhole Friction Stir Welding for 6061-T6 Aluminum Alloy

A novel non-keyhole friction stir welding technique was proposed to weld the butt joint of 6061-T6 aluminum alloy with the thickness of 6 mm. A sound joint was obtained by this technique, simultaneously eliminating the flash, shoulder mark and keyhole defects. The sleeve directly affected zone (SDAZ) and the sleeve indirectly affected zone (SIAZ) were divided into the joint according to the plunging position of the hollow sleeve. The lack of root penetration defect was avoided when the plunging depth of the hollow sleeve was only 4.2 mm, because the hollow part inside the sleeve improved the material flow below the sleeve. An S-shaped line was left at the SIAZ, and the height of it had the minimum value of 1.47 mm at 20 mm/min. Whether the failure location of the joint was in SIAZ/SDAZ or the heat-affected zone (HAZ) depended on the height and bonding strength of the S-shaped line. The joint fracture location changed from the SIAZ/SDAZ at 35 mm/min to the HAZ at 20 and 30 mm/min. The maximum tensile strength of 224.3 MPa was obtained at 30 mm/min which was 73.7% of that of the base material. The fracture surface morphology exhibited the typical ductile fracture.     

VO2/GaAs异质结的制备及其光电特性研究

采用直流磁控溅射和后退火氧化工艺在p型GaAs单晶衬底上成功制备了n-VO_2/pGaAs异质结,研究了不同退火温度和退火时间对VO_2/GaAs异质结性能的影响,并分析其结晶取向、化学组分、膜层质量以及光电特性。结果表明,在退火时间2 h和退火温度693 K下能得到相变性能最佳的VO_2薄膜,相变前后电阻变化约2个数量级。VO_2/GaAs异质结在308 K、318 K和328 K温度下具有较好的整流特性,对应温度下的阈值跳变电压分别为6.9 V、6.6 V和6.2 V,该结果为基于VO_2相变特性的异质结光电器件的设计与应用提供了可行性。     

BOPET薄膜市场现状分析及发展趋势

基础BOPET全球生产市场需求分析,尤其对中国BOPET的市场需求、市场分布、生产厂家、产能等全方面进行了分析,得出BOPET行业市场发展将向再生利用、生物可降解、绿色改性以及降低单耗等五方面可持续发展.     

Effect of Cu-Rich Phase Precipitation on the Microstructure and Mechanical Properties of CoCrNiCux Medium-Entropy Alloys Prepared via Laser Directed Energy Deposition

CoCrNiCux (x=0.16,0.33,0.75,and 1) without macro-segregation medium-entropy alloys (MEAs) was prepared using laser directed energy deposition (LDED).The microstructure and mechanical properties of CoCrNiCux alloys with increas-ing Cu content were investigated.The results indicate that a single matrix phase changes into a dual-phase structure and the tensile fracture behaviors convert from brittle to plastic pattern with increasing Cu content in CoCrNiCux alloys.In addi-tion,the tensile strength of CoCrNiCux alloys increased from 148 to 820 MPa,and the ductility increased from 1 to 11％with increasing Cu content.The nano-precipitated particles had a mean size of approximately 20 nm in the Cu-rich phase area,and a large number of neatly arranged misfit dislocations were observed at the interface between the two phases due to Cu-rich phase precipitation in the CoCrNiCu alloy.These misfit dislocations hinder the movement of dislocations during tensile deformation,as observed through transmission electron microscopy.This allows the CoCrNiCu alloy to reach the largest tensile strength and plasticity,and a new strengthening mechanism was achieved for the CoCrNiCu alloy.Moreover,twins were observed in the matrix phase after tensile fracture.Simultaneously,the dual-phase structure with different elastic moduli coordinated with each other during the deformation process,significantly improving the plasticity and strength of the CoCrNiCu alloy.     

Crystallographic characteristics and microwave dielectric properties of Ni-modified MgTa2O6 ceramics

Ni²⁺ modified MgTa₂O₆ ceramics with a trirutile phase and space group P4₂/mnm were obtained. The correlations between crystallographic characteristics and microwave dielectric performance of MgTa₂O₆ ceramics were systematically studied based on the chemistry bond theory (PVL theory) for the first time. The results indicate that the introduction of Ni²⁺ causes a change in polarizability and the Mg–O bond ionicity, which contributes to the variation of dielectric constant. Moreover, the lattice energy, and packing fraction, full width at half maximum of the Raman peak of Ta–O bond, as the quantitative characterization of crystallographic parameters, regulate the dielectric loss of MgTa₂O₆ ceramics in GHz frequency band. In addition, the study of sintering behavior shows that the densification and micromorphology are the crucial factors affecting the microwave dielectric performance. Typically, Ni²⁺ doping on the A-site of MgTa₂O₆ can effectively promote the Q × f values to 173,000 GHz (at 7.43 GHz), which ensures its applicability in 5G communication technology.     

含功效成分电子烟对动物模型止咳平喘作用研究

为考察电子烟作为功效成分递送器具的效果,选取L-薄荷醇、L-茶氨酸、丁香酚、木香烃内酯、西贝碱、菖蒲酮、7,4'-二羟基黄酮7种功效化合物和1种臭灵丹提取物,通过氨水引咳小鼠咳嗽模型和卵清蛋白(OVA)引喘大鼠哮喘模型,评价上述物质在电子烟中止咳平喘疗效.结果 显示:1)止咳效果方面.上述8种物质均减少了咳嗽模型小鼠的咳嗽次数,同时不同程度延长了咳嗽模型小鼠咳嗽潜伏期;2)平喘效果方面.上述8种物质对哮喘模型大鼠肺功能各指标均有改善,其中L-薄荷醇对呼气时间(简称"Te")、50％的呼气流速(简称"EF50％")有明显改善;L-茶氨酸对Te、最大呼气流速(简称"PEF")和EF50％有明显改善;丁香酚对PEF、EF50％和呼气量(简称"EV'")有明显改善;木香烃内酯对PEF和EV有明显改善;西贝碱对Te、PEF有明显改善;菖蒲酮对Te、PEF有明显改善;7,4'-二羟基黄酮对PEF和EV有明显改善;臭灵丹提取物对PEF和EF50％有明显改善;3)Model组大鼠存在明显哮喘病理改变:肺基底膜增厚并发生玻璃样变,相比Model组,8组接受功效型电子烟烟雾暴露的哮喘模型大鼠支气管哮喘均有改善.以上说明,电子烟作为具有止咳平喘功效成分的递送器具效果明显,这为功效型电子烟的开发提供了参考.     

Pressure-induced transparency of MgO,Al2O3, AlN,and cBN ceramics at room temperature

The in situ axial X-ray diffraction patterns of four ceramic powder samples (MgO, Al₂O₃, AlN, and cBN) that were compressed in a diamond anvil cell under uniaxial non-hydrostatic conditions were recorded. The microscopic deviatoric stress as a function of the pressure was determined from the X-ray diffraction peak broadening analysis: the curves increased approximately linearly with the pressure at the initial compression stage and then levelled off under further compression. Pressure-induced transparency was observed in all of the samples under compression, and the pressure at the turning point on the curves of the microscopic deviatoric stress versus pressure corresponded to the pressure at which the samples became transparent. Analysis of the microstructural features of the pressure-induced transparent samples indicated that the compression caused the grains to fracture, and the broken grains bonded with each other. We demonstrated that the ceramics’ pressure-induced transparency was a process during which the grains were squeezed and broken, the pores were close between the grains, and the broken grains were re-bonded under compression.     

Large domain-wall currents in epitaxial Au/BiFeO3/SrRuO3 thin-film capacitors with modulated oxygen vacancy and wall densities

Large domain wall (DW) conductivity in an insulating ferroelectric plays an important role in the future nanosensors and nonvolatile memories. However, the wall current was usually too small to drive high-speed memory circuits and other agile nanodevices requiring high output-powers. Here, a large domain-wall current of 67.8 μA in a high on/off ratio of ~4460 was observed in an epitaxial Au/BiFeO₃/SrRuO₃ thin-film capacitor with the minimized oxygen vacancy concentration. The studies from read current-write voltage hysteresis loops and piezo-response force microscope images consistently showed remaining of partially unswitched domains after application of an opposite poling voltage that increased domain wall density and wall current greatly. A theoretical model was proposed to explain the large wall current. According to this model, the domain reversal occurs with the appearance of head-to-head and tail-to-tail 180° domain walls (DWs), resulting in the formation of highly conductive wall paths. As the applied voltage increased, the domain-wall number increased to enhance the on-state current, in agreement with the measurements of current-voltage curves. This work paves a way to modulate DW currents within epitaxial Au/BiFeO₃/SrRuO₃ thin-film capacitors through the optimization of both oxygen vacancy and domain wall densities to achieve large output powers of modern domain-wall nanodevices.