Inflammatory Mechanism of Brucella Infection in Placental Trophoblast Cells

Brucellosis is a severe zoonotic infectious disease caused by the infection of the Brucella, which is widespread and causes considerable economic losses in underdeveloped areas. Brucella is a facultative intracellular bacteria whose main target cells for infection are macrophages, placental trophoblast cells and dendritic cells. The main clinical signs of Brucella infection in livestock are reproductive disorders and abortion. At present, the pathogenesis of placentitis or abortion caused by Brucella in livestock is not fully understood, and further research on the effect of Brucella on placental development is still necessary. This review will mainly introduce the research progress of Brucella infection of placental trophoblast cells as well as the inflammatory response caused by it, explaining the molecular regulation mechanism of Brucella leading to reproductive system disorders and abortion, and also to provide the scientific basis for revealing the pathogenesis and infection mechanism of Brucella.     

电渣重熔铸铁渣系的选择

介绍铸铁重熔的一些实验结果,对提出的CaF₂ 50%、CaO 30%、Al₂O₃ 10%、MgO₅、SiO₂ 5%五元渣进行了熔点、粘度和电导的测定与讨论。多炉的重熔试验表明,该渣系对铸铁重熔有较好的适应性。     

铸造铁水的电渣精炼

本文介绍了电渣精炼铸造铁水的实验室和半工业性实验的结果。结果表明,电渣精炼过程的脱硫、去气、去夹杂对获得优质铁水,提高铸件质量有明显的效果。但脱磷效果不明显。精炼铁水球化效果好并可大量降低球化剂的消耗。因此,新工艺有可能代替传统的铸造铁水熔炼工艺。     

电渣铸铁—现状和展望

六十年代末,七十年代初,苏联冶金学者开始了电渣铸铁的研究工作。电渣重熔和电渣精炼过程的脱硫,脱磷、除夹杂、除气等作用对获得优质铁水,提高铸件质量有明显效果。特别是在直流制度下熔炼,有可能发挥电化学作用。有目的地从熔体中排除有害元素或从熔渣中获得合金化元素,因此,试图采用电渣重熔或电渣精炼进行变性处理和合金化取代添加球化剂直接得到球墨铸铁的生产技术引起人们极大的兴趣。
虽然电渣铸铁工艺和生产技术本身尚有改进的方面,而且对某些基本理论的研究仍处于探讨阶段。然而,作为一种铸铁精炼的新方法,有可能从根本上改革现行的生产工艺。
本文收集了十多年来有关电渣铸铁的文献资料,概括了国外有关电渣生铁熔炼的研究内容和成果。结合我国资源条件及工业发展特点,对开展电渣铸铁工艺和理论研究工作提出一些建议。     

不锈钢Ⅲ型试样的氢致开裂和应力腐蚀

研究了奥氏体不锈钢Ⅲ型试样的氢致开裂和应力腐蚀。结果表明,动态充氢时Ⅲ型试样也能发生氢致滞后断裂,且裂纹沿原缺口平面形核和扩展。从而可获得宏观平滑的扭转断口,但断口上存在少量沿45°面的二次裂纹,一系列实验表明动态充氢能促进奥氏体不锈钢室温蠕变,故在恒扭矩下充氢能使扭转角不断增大,直至试样被扭断。奥氏体不锈钢Ⅲ型试样在42%沸腾MgCl₂溶液中也能发生应力腐蚀开裂,且裂纹在与缺口平面成45°的平面上形核和扩展。实验表明,无论是Ⅰ型还是Ⅲ型,应力腐蚀的门槛值均比氢致滞后断裂门槛值要低,例如K_ⅠSCC/K_ⅠX=0.18,K₍ⅠH/K_ⅠX=0.58,K_ⅢSCC/K_ⅢX=0.13 K_ⅢH/K_ⅢX=0.62。     

硼在渗层中的行为与渗层淬透性

含硼钢化学热处理时,由于C、N、B之间的相互作用,B在整个渗层范围内发生明显的再分布在渗碳层中主要表现为表层B的富集和次表层B的贫化;在碳氮共渗层中则主要表现为表层和次表层内有大量BN形成以及在很宽的范围内固溶硼量很低
B的这种再分布对渗层材料的淬透性带来显著影响。在渗碳层中,除了要考虑C本身的作用和C对B效应的影响外,还要考虑次表层B贫化的影响。在碳氮共渗层中,大量BN的形成对渗透性有显著的不利影响,固溶硼贫化的作用也表现得更为突出。     

铸钢和锻钢应力腐蚀性能的对比研究

用同一炉钢的铸件和锻件对比研究了在水介质中的应力腐蚀性能,结果表明,铸钢和锻钢应力腐蚀裂纹扩展的激活能相同,均为Q=5540cal/mol。且和氢渗透测出的表观扩散激活能Q=6010cal/mol相—致。无论是阳极极化还是阴极极化均使铸钢和锻钢的da/dt升高,但阴极极化更为明显,氢渗透测量表明,无论是阳极极化还是阴极极化,随电流增大,饱和氢渗透通量明显增加;极化对da/dt和氢渗透通量影响是相似的。
实验表明,试验温度对KIscc影响极小,但铸钢的KIscc明显比锻钢要高。氢渗透测试表明,锻钢的饱和氢渗透通量约比铸钢要大一倍,这就可解释KIscc的差异,这也和断口观察相一致,尽管断口形貌明显依赖开裂时的KI值,但在KIscc附近锻钢全是沿晶断口,而铸钢则以准解理为主。     

Adaptive river segmentation in SAR images

There is difficulty for distinguishing of river and shadow in Synthetic Aperture Radar (SAR) images. A method of river segmentation in SAR images based on wavelet energy and gradient is proposed in this paper. It mainly includes two algorithms: coarse segmentation and refined segmentation. Firstly, The river regions are coarsely segmented by the wavelet energy feature,and then refined segmented accurately by the gradient threshold which is got adaptively. The experimental results show the validity of the method, which provides a good foundation for targets detection above the river.     

CCL4 Regulates Eosinophil Activation in Eosinophilic Airway Inflammation

Eosinophilic chronic rhinosinusitis (ECRS) is a refractory airway disease accompanied by eosinophilic inflammation, the mechanisms of which are unknown. We recently found that CCL4/MIP-1β—a specific ligand for CCR5 receptors—was implicated in eosinophil recruitment into the inflammatory site and was substantially released from activated eosinophils. Moreover, it was found in nasal polyps from patients with ECRS, primarily in epithelial cells. In the present study, the role of epithelial cell-derived CCL4 in eosinophil activation was investigated. First, CCL4 expression in nasal polyps from patients with ECRS as well as its role of CCL4 in eosinophilic airway inflammation were investigated in an in vivo model. Furthermore, the role of CCL4 in CD69 expression—a marker of activated eosinophils—as well as the signaling pathways involved in CCL4-mediated eosinophil activation were investigated. Notably, CCL4 expression, but not CCL5, CCL11, or CCL26, was found to be significantly increased in nasal polyps from patients with ECRS associated with eosinophil infiltration as well as in BEAS-2B cells co-incubated with eosinophils. In an OVA-induced allergic mouse model, CCL4 increased eosinophil accumulation in the nasal mucosa and the bronchoalveolar lavage (BALF). Moreover, we found that CD69 expression was upregulated in CCL4-stimulated eosinophils; similarly, phosphorylation of several kinases, including platelet-derived growth factor receptor (PDGFR)β, SRC kinase family (Lck, Src, and Yes), and extracellular signal-regulated kinase (ERK), was upregulated. Further, CCR5, PDGFRβ, and/or Src kinase inhibition partially restored CCL4-induced CD69 upregulation. Thus, CCL4, which is derived from airway epithelial cells, plays a role in the accumulation and activation of eosinophils at inflammatory sites. These findings may provide a novel therapeutic target for eosinophilic airway inflammation, such as ECRS.