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991.
Chen Zhang a Paul Thoma b Bryan Chin a Ralph Zee a a Materials Engineering Program Auburn University AL U.S.A. b Johnson Controls Inc. Milwaukee WI U.S.A. 《中国有色金属学会会刊》1999,(Z1)
1 INTODUCTIONShapememoryalloys(SMAs)areexcellentcandidatesforcontrolsystemsandarecommonlyreferredtoas“smart”materialsduetotheirabilitytochangeshapewithtemperature.Thesealloyscanalsogeneratesignificantamountsofstrain(andstress)andareidealforuseinact… 相似文献
992.
MD McKisic JD Macy ML Delano RO Jacoby FX Paturzo AL Smith 《Canadian Metallurgical Quarterly》1998,65(11):1436-1446
BACKGROUND: The recently identified autonomous mouse parvovirus designated mouse parvovirus-1 (MPV-1) persists in adult BALB/c mice for at least 9 weeks, infects lymphoid tissues, interferes with the ability of cloned T cells to proliferate, and exhibits immunomodulatory properties. As a consequence of these findings, the present studies were undertaken to characterize further the inmunomodulatory effects of MPV-1 on T cell-mediated immune responses in vivo and in vitro. METHODS: To evaluate the effect of MPV-1 infection on CD8+ T cell-mediated responses, BALB/c-H2dm2 mice were infected after transplantation of allogeneic BALB/c skin. RESULTS: MPV-1 potentiated the rejection of allogeneic skin grafts. This potentiation was not a result of virus infecting the cellular or vascular component of the graft as determined by in situ hybridization, but was mediated by T cells. However, the proliferative capacity of alloantigen-reactive lymphocytes from graft-sensitized infected mice was diminished. MPV-1 also induced the rejection of syngeneic skin grafts, and T cells from these infected graft-sensitized mice lysed syngeneic P815 target cells. CONCLUSIONS: These results suggest that MPV-1 infection of skin-grafted mice may disrupt normal mechanisms of peripheral tolerance and provide a unique model to study virus-induced autoimmunity. 相似文献
993.
L Contu C Carcassi S Orrù M Mulargia M Arras R Boero S Gessa AL Loizedda S Lai L Floris 《Canadian Metallurgical Quarterly》1998,52(5):452-461
The hypothesis of a possible selective role of malaria in HLA allele frequency variations was investigated in Sardinia by typing completely 1,039 individuals for HLA: 536 from six lowland villages exposed to malaria until 1948, and 503 from six highland villages with no history of malaria. Another 1,928 individuals from 136 villages scattered all over the island were studied to establish if the HLA allele frequencies among villages correlated with the malaria incidence and/or altitude above sea level. Only the HLA-B35 allele yielded significantly higher frequencies in the lowland versus the highland villages (P<1 x 10(-5)). The observed B35 variance was 9.5 times higher than expected in the absence of selection, showing an adaptive origin. The highly significant positive correlation found between HLA-B35 frequency and malaria in 136 villages suggests that malaria has been the selective factor for HLA-B35 in Sardinia. 相似文献
994.
In Washington state, practicing physicians have been forced to confront the emotional, complex issue of physician-assisted suicide sooner than physicians elsewhere in the US. The Washington State Medical Association has struggled at length with the issue and ultimately delineated a policy on safeguards for physician-assisted suicide. The Washington experience may prove instructive to other professional physician organizations even before the US Supreme Court rules on the issue. 相似文献
995.
AL Carse 《Canadian Metallurgical Quarterly》1998,23(2):153-169
This essay critically assesses two strategies of accommodation used by defenders of impartialism in ethics to argue that the care orientation represents no genuine challenge to impartialist theoretical paradigms. One strategy focuses on impartiality as a constraint on moral deliberation, the other as a constraint on moral justification. While highlighting respects in which the commitment to impartiality is more consonant with the care orientation than many advocates of care have acknowledged, this essay attempts to clarify crucial ways in which each accommodationist strategy fails, thus locating some of the more important contributions and challenges the care orientation offers to moral theory. 相似文献
996.
Marvin J.W. Labovitz M.L. Wolfe R.E. 《Geoscience and Remote Sensing, IEEE Transactions on》1987,(2):244-251
Earth-viewing satellite sensors (e. g., the Landsat 4/5 Thematic Mapper) produce images with nontrivial amounts of geometric distortion due to local terrain variations. Although correction formulas are easy to derive, the high frequency of terrain variation relative to pixel size means that excessive computer time is required to process a large digital image. This paper derives approximations to the correction geometry that reduce computer time by orders of magnitude. A statistical sensitivity analysis shows that the approximations do not adversely affect the accuracy of the results even under a very demanding error budget. 相似文献
997.
Extracanal invasive resorption is not a well-defined phenomenon. This article describes its clinical, radiographic, and histological characteristics. Treatment of affected teeth based on the location of the resorptive defect is also described. 相似文献
998.
This work shows that single sequencing reactions analyzed on an automated DNA sequencer can be an efficient way of screening PCR products for known mutations. We have analyzed a mutation in exon 10 of the human aromatase gene and show that an unambiguous genotype could be elucidated in more than 90% of the analyzed samples. Compared to analysis by full sequencing, 4 times more samples can be analyzed per gel, so that the sample capacity of the gel is approaching that of alternative gel-based methods for genotype analysis. Unlike many of these, the method offers direct identification of the variant sequence position and on-line analysis without the need of post-electrophoretic processing of the gel. 相似文献
999.
H Nakajima MR Aupart PH Neville AL Sirinelli YA Meurisse MA Marchand 《Canadian Metallurgical Quarterly》1998,7(5):534-539
BACKGROUND: The purpose of the present study was to investigate the therapeutic effectiveness of interleukin-2 (IL-2) and interferon (IFN), either alone or in combination, in comparable groups of patients affected by advanced renal cell carcinoma (RCC). PATIENTS AND METHODS: In order to limit selection biases, treatment was allocated on a random basis. Patients randomized to IL-2 alone were scheduled to receive eight rlL-2 24-hour i.v. infusion cycles, days 1 to 4, at a daily dose of 18 x 10(6) lU/m2 for a total of 25 weeks. Patients randomized to IFN alone were scheduled to receive rIFN-alpha at a daily dose of 6 x 10(6) IU/m2, days 1, 3 and 5, every week for a total of 52 weeks. Patients randomized to the combination of IFN and IL-2 were given the same drugs at the same daily doses for a total of 24 weeks. Drug dose was modified according to toxicity. RESULTS: Twenty-three percent (95% CI:+/-17.5) of patients treated with IL-2 alone showed an objective response to treatment (9% CR). The corresponding figures in patients treated with IFN alone or IFN plus IL-2 were 9% (95% CI:+/-11.9) and 9% (95% CI:+/-11.9), respectively. Complete responses were observed only in patients treated with IL-2. The median duration of response in the IL-2 arm was 18 months (range, 9.5-24). The duration of the two responses achieved by IFN alone was seven and nine months, respectively. The corresponding figures in the two patients responding to the combination of IFN with IL-2 were 19 and 27 months, respectively. Total IL-2 dose appeared to be a major predictor of response. Only a minority of patients experienced grade 3-4 toxicity, the incidence being higher in those treated with IL-2 or IL-2 plus IFN. CONCLUSIONS: Neither IFN nor IL-2 or the combination of the two appear to be very active in patients with advanced RCC, even when trial entry was restricted to patients with relatively indolent disease. This stresses the need for the development of new approaches. 相似文献
1000.
The immune responses generated after infection with Eimeria spp. are complex, include both cellular and humoral components, and lead to protection against re-infection. To facilitate the rational development of the next generation of anticoccidial vaccines it is important that the nature of the immunoprotective response against infection with Eimeria spp. is determined. In this brief report we discuss results that were obtained using a combination of genetic and cellular approaches to dissect the essential immune effector components that operate against infection with Eimeria vermiformis. Mice rendered deficient of immune function by targeted gene disruption at a variety of immune loci represent an integral component of our studies and include those with targeted gene disruption at loci that encode the B- and T-cell receptors (BCR, TCR), antigen presentation molecules and immune-effector molecules. Our studies demonstrated that TCR-alpha-beta + T cells are essential for immunoprotection during both primary and secondary infection. Moreover, during primary infection the major effector cell type is a population of major histocompatibility complex class II-restricted, interferon-gamma-producing TCR-alpha-beta T cell consistent with a T helper 1 phenotype. In addition, there is a supplementary role for another class of cells (presumably T cells) that are restricted to either non-classical antigen presentation molecules or classical major histocompatibilty complex class I loaded via an atypical pathway. Mice with a deficiency in interleukin-6 were slightly more susceptible to primary infection than intact animals, consistent with the reported effects of interleukin-6 upon the generation of T helper 1-type responses in vivo. In terms of the host response to re-infection, TCR-alpha-beta T cells were essential for immunity, but the requirement for specific cell subsets and effector mechanisms was much less stringent. Mice deficient in gamma-delta T cells, classical major histocompatibility complex class I, non-classical antigen presentation pathways, the cytokines interferon-gamma, interleukin-4, interleukin-6 and the cytolytic effector molecules perforin or FasL were completely immune to secondary infection. Moreover, major histocompatibility complex class II-deficient I-A-beta-/- mice were capable of mounting a substantial response to secondary infection, manifest by a 95% reduction in oocyst output compared with primary infection. These data have important consequences for the development of immune intervention strategies and indicate that vaccine development may be targeted toward the generation of a wider range of effector mechanisms than those that operate during primary infection. 相似文献