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951.
Effect of high anodic polarization on the passive layer properties of superduplex stainless steel friction stir welds at different chloride electrolyte pH values and temperatures 下载免费PDF全文
L. A. Santa-Cruz G. Machado A. A. Vicente T. F. C. Hermenegildo T. F. A. Santos 《矿物冶金与材料学报》2019,26(6):710-721
The conditions used for friction stir welding of duplex stainless steels determine the resulting mechanical and corrosion performance of the material.This study investigates the corrosion resistance of UNS S32750 and S32760 superduplex stainless steels(SDSSs)joined by friction stir welding,employing cyclic polarization,Mott–Schottky,and microscopy techniques for analysis.The microscopy images indicated the presence of a deleterious intermetallic phase after electrolytic etching of S32760,as well as decreased corrosion resistance.The presence of molybdenum in the steels promoted better passive behavior at low pH.The Mott–Schottky curves revealed p-n heterojunction behavior of the passive oxide.Images acquired after the polarization test by scanning electron microscopy showed higher passivation propensity with increases of temperature and pH. 相似文献
952.
Insulin gene enhancer binding protein Isl-1 is a member of a novel class of proteins containing both a homeo- and a Cys-His domain. 总被引:57,自引:0,他引:57
The activity of the rat insulin I gene enhancer is mainly dependent on two cis-acting protein-binding domains. Here we report the isolation of a complementary DNA encoding a protein, Isl-1, that binds to one of these domains. Isl-1 contains a homeodomain with greatest similarity to those of the Caenorhabditis elegans proteins encoded by mec-3 and lin-11. In addition, Isl-1, like the lin-11 and mec-3 gene products, contains a novel Cys-His domain which is reminiscent of known metal-binding regions. Together these proteins define a novel class of proteins containing both a homeo- and a Cys His-domain. Isl-1 is preferentially expressed in cells of pancreatic endocrine origin. If the structural homologies between Isl-1 and the C. elegans gene products reflect functional similarities, a role for Isl-1 in the development of pancreatic endocrine cells could be envisaged. 相似文献
953.
K. Hedlund H. Ek T. Gunnarsson C. Svegborn 《Cellular and molecular life sciences : CMLS》1990,46(5):524-526
Summary Both male and femaleOrchesella cincta (Collembola) were able to discriminate between spermatophores of different origin. Females chose spermatophores deposited by closely related males while males preferentially destroyed spermatophores of other males. 相似文献
954.
955.
S M Sisodiya S L Free K A Williamson T N Mitchell C Willis J M Stevens B E Kendall S D Shorvon I M Hanson A T Moore V van Heyningen 《Nature genetics》2001,28(3):214-216
PAX6 is widely expressed in the central nervous system. Heterozygous PAX6 mutations in human aniridia cause defects that would seem to be confined to the eye. Magnetic resonance imaging (MRI) and smell testing reveal the absence or hypoplasia of the anterior commissure and reduced olfaction in a large proportion of aniridia cases, which shows that PAX6 haploinsuffiency causes more widespread human neuro developmental anomalies. 相似文献
956.
957.
Microinjection of insulin (0.04-0.12 IU/microliter) into the anterior hypothalamus or the lateral hypothalamus, but not the ventromedial hypothalamus of the rat brain, caused a dose-dependent rise in blood glucose and in serum insulin. The majority (71.5%) of the glucose-facilitated neurons recorded in the lateral hypothalamic area were excited by intracerebral injection of insulin. The data indicate that insulin acts on the hypothalamic glucose-facilitated neurons to induce hyperglycemia and hyperinsulinemia. It is unknown whether insulin normally reaches the hypothalamic area, or how it might do so. 相似文献
958.
Selective attraction of monocytes and T lymphocytes of the memory phenotype by cytokine RANTES. 总被引:101,自引:0,他引:101
An important process in the immune response is the migration of different populations of lymphocytes at the proper time to sites of antigenic challenge. Although several chemoattractants are known for broad classes of lymphocytes, such as T and B cells, the process by which lymphocytes of specific subsets, such as helper, cytotoxic or memory T cells, migrate to the appropriate sites remains obscure. Interleukin-8 is a chemoattractant for T cells and neutrophils and is a member of a superfamily of soluble molecules related by a conserved motif containing four cysteine residues. IL-8 and related molecules, including platelet factor 4, constitute the C-X-C class of the superfamily and a group of cytokines produced by haematopoietic cells constitute the RANTES/sis or C-C class. The roles of most of these molecules are not well known, although murine MIP-1 alpha of the C-C branch is a specific inhibitor of haematopoietic stem cell proliferation and some members of the C-X-C branch are neutrophil-targeted inflammatory agents. Here we report that the RANTES protein of the C-C class causes the selective migration of human blood monocytes and of T lymphocytes expressing the cell surface antigens CD4 and UCHL1. CD4+/UCHL1+T cells are thought to be prestimulated or primed helper T cells involved in memory T cell function. The preferential attraction of T-cell subsets by specific cytokines could in part explain how lymphocytes are targeted, and may provide insight into the workings of T cell memory. 相似文献
959.
G. O. Poinar Jr R. T. Hess W. Lanier S. Kinney J. H. White 《Cellular and molecular life sciences : CMLS》1989,45(2):191-192
A bacteriophage infective toXenorhabdus luminescens, a bacterial symbiont of heterorhabditid nematodes, was recovered from insects that supported poor nematode development. Plaque tests showed the phage particles to be infective only to primary and not secondary colonies ofX. luminescens. The phage was not infective toX. nenatophilus primaries or secondaries. The bacteriophage particles ranged 80–90 nm in length, with the head ranging from 40 to 50 nm in diameter. Restriction analysis was performed on isolated bacteriophage DNA. This first report of a bacteriophage fromXenorhabdus species has pratical implications since it could be detrimental to cultures ofHeterorhabditis nematodes that are being produced throughout the world for the biological control of insects. 相似文献
960.
T Tameyasu 《Experientia》1990,46(7):677-679
Changes in the profile of equatorial intensities of X-ray diffraction from an intact, anterior byssal retractor muscle (ABRM) of Mytilus were examined at rest, during contracture brought about by acetylcholine (ACh) and a subsequent rigor-like contraction caused by raising the tonicity of the external solution, and after returning the tonicity to normal. The results suggest that the cross-bridges formed between thick and thin actin filaments during the ACh-contracture were maintained in the hypertonic solution and broken on decreasing the tonicity before the recovery of spacing of the actin filament lattice. A similar rigor-like contraction was induced in glycerinated ABRM by increasing salt concentration during active contraction. The rigor-like force declined rapidly when Ca++ concentration decreased. The results suggest that the detachment of the cross-bridge from the actin filament is regulated by Ca++ at high ionic strength in the ABRM. 相似文献