Addition of cerium and yttrium to ferritic steel weld metal to improve hydrogen trapping efficiency

The applicability of Ce and Y as promising candidate elements to form irreversible traps in weld metal was investigated by thermal desorption spectroscopy (TDS) with gas chromatography (GC).The precise nature of the precipitate particles newly formed in the weld metal by the addition of Ce and Y to a certain alloy system was characterized.Moreover,the hydrogen trapping efficiency expressed as the reduction of the diffusible hydrogen in the weld metal was analyzed.The results showed that the addition of Ce and/or Y to this alloy system led to the formation of a mixed type of (Ce,Ti)-based oxide,(Y,Ni)-based carbide,or (Ce,Y,Ti)-based oxide particles.Because of the high activation energy of the mixed type of particles (≥ 150 kJ/mol),the trapping efficiency for hydrogen was considered to be sufficiently high to effectively reduce the diffusible hydrogen content.     

Phosphorylation of WAVE1 regulates actin polymerization and dendritic spine morphology

WAVE1--the Wiskott-Aldrich syndrome protein (WASP)--family verprolin homologous protein 1--is a key regulator of actin-dependent morphological processes in mammals, through its ability to activate the actin-related protein (Arp2/3) complex. Here we show that WAVE1 is phosphorylated at multiple sites by cyclin-dependent kinase 5 (Cdk5) both in vitro and in intact mouse neurons. Phosphorylation of WAVE1 by Cdk5 inhibits its ability to regulate Arp2/3 complex-dependent actin polymerization. Loss of WAVE1 function in vivo or in cultured neurons results in a decrease in mature dendritic spines. Expression of a dephosphorylation-mimic mutant of WAVE1 reverses this loss of WAVE1 function in spine morphology, but expression of a phosphorylation-mimic mutant does not. Cyclic AMP (cAMP) signalling reduces phosphorylation of the Cdk5 sites in WAVE1, and increases spine density in a WAVE1-dependent manner. Our data suggest that phosphorylation/dephosphorylation of WAVE1 in neurons has an important role in the formation of the filamentous actin cytoskeleton, and thus in the regulation of dendritic spine morphology.     

Crystal structure of an HIV-binding recombinant fragment of human CD4

CD4 glycoprotein on the surface of T cells helps in the immune response and is the receptor for HIV infection. The structure of a soluble fragment of CD4 determined at 2.3 A resolution reveals that the molecule has two intimately associated immunoglobulin-like domains. Residues implicated in HIV recognition by analysis of mutants and antibody binding are salient features in domain D1. Domain D2 is distinguished by a variation on the beta-strand topologies of antibody domains and by an intra-sheet disulphide bridge.     

Th1-specific cell surface protein Tim-3 regulates macrophage activation and severity of an autoimmune disease

Activation of naive CD4(+) T-helper cells results in the development of at least two distinct effector populations, Th1 and Th2 cells. Th1 cells produce cytokines (interferon (IFN)-gamma, interleukin (IL)-2, tumour-necrosis factor (TNF)-alpha and lymphotoxin) that are commonly associated with cell-mediated immune responses against intracellular pathogens, delayed-type hypersensitivity reactions, and induction of organ-specific autoimmune diseases. Th2 cells produce cytokines (IL-4, IL-10 and IL-13) that are crucial for control of extracellular helminthic infections and promote atopic and allergic diseases. Although much is known about the functions of these two subsets of T-helper cells, there are few known surface molecules that distinguish between them. We report here the identification and characterization of a transmembrane protein, Tim-3, which contains an immunoglobulin and a mucin-like domain and is expressed on differentiated Th1 cells. In vivo administration of antibody to Tim-3 enhances the clinical and pathological severity of experimental autoimmune encephalomyelitis (EAE), a Th1-dependent autoimmune disease, and increases the number and activation level of macrophages. Tim-3 may have an important role in the induction of autoimmune diseases by regulating macrophage activation and/or function.     

Determining multiple length scales in rocks

Carbonate reservoirs in the Middle East are believed to contain about half of the world's oil. The processes of sedimentation and diagenesis produce in carbonate rocks microporous grains and a wide range of pore sizes, resulting in a complex spatial distribution of pores and pore connectivity. This heterogeneity makes it difficult to determine by conventional techniques the characteristic pore-length scales, which control fluid transport properties. Here we present a bulk-measurement technique that is nondestructive and capable of extracting multiple length scales from carbonate rocks. The technique uses nuclear magnetic resonance to exploit the spatially varying magnetic field inside the pore space itself--a 'fingerprint' of the pore structure. We found three primary length scales (1-100 microm) in the Middle-East carbonate rocks and determined that the pores are well connected and spatially mixed. Such information is critical for reliably estimating the amount of capillary-bound water in the rock, which is important for efficient oil production. This method might also be used to complement other techniques for the study of shaly sand reservoirs and compartmentalization in cells and tissues.     

Neural population dynamics during reaching

Most theories of motor cortex have assumed that neural activity represents movement parameters. This view derives from what is known about primary visual cortex, where neural activity represents patterns of light. Yet it is unclear how well the analogy between motor and visual cortex holds. Single-neuron responses in motor cortex are complex, and there is marked disagreement regarding which movement parameters are represented. A better analogy might be with other motor systems, where a common principle is rhythmic neural activity. Here we find that motor cortex responses during reaching contain a brief but strong oscillatory component, something quite unexpected for a non-periodic behaviour. Oscillation amplitude and phase followed naturally from the preparatory state, suggesting a mechanistic role for preparatory neural activity. These results demonstrate an unexpected yet surprisingly simple structure in the population response. This underlying structure explains many of the confusing features of individual neural responses.     

The effects of microinjection of carbachol or hemicholinium into the amygdala on the levels of plasma and adrenal corticosterone in rats

Microinjections of 0.4 microgram of carbachol into the amygdala caused a rise of corticosterone (CS) in the morning when the prestimulating level of CS was lower. But the same procedure with a larger dose had no effect in the afternoon, when the prestimulating level of CS was higher.     

Optic atrophy 3 as a protein of the mitochondrial outer membrane induces mitochondrial fragmentation

The optic atrophy 3 (OPA3) gene, which has no known homolog or biological function, is mutated in patients with hereditary optic neuropathies. Here, we identified OPA3 as an integral protein of the mitochondrial outer membrane (MOM), with a C-terminus exposed to the cytosol and an N-terminal mitochondrial targeting domain. By quantitative analysis, we demonstrated that overexpression of OPA3 significantly induced mitochondrial fragmentation, whereas OPA3 knockdown resulted in highly elongated mitochondria. Cells with mitochondria fragmented by OPA3 did not undergo spontaneous apoptotic cell death, but were significantly sensitized to staurosporine- and TRAIL-induced apoptosis. In contrast, overexpression of a familial OPA3 mutant (G93S) induced mitochondrial fragmentation and spontaneous apoptosis, suggesting that OPA3 mutations may cause optic atrophy via a gain-of-function mechanism. Together, these results indicate that OPA3, as an integral MOM protein, has a crucial role in mitochondrial fission, and provides a direct link between mitochondrial morphology and optic atrophy.     

一个福利设施的热环境和问卷调查

为探讨热环境对居住在福利院中的老龄人的感受的影响．选择若干老人福利院作为研究对象，对其热湿环境加以测量，并利用夏季时间对老龄人对热环境的反应进行了调查．