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41.
Kell and Kx are two quantitatively minor proteins from the human erythrocyte membrane which carry blood groups antigens and are thought to be a metalloprotease and a membrane transporter, respectively. In the red cell membrane, these proteins form a complex stabilized by disulfide bond(s). Phosphorylation status of these proteins was studied, in the presence or absence of effectors of several kinases, either on intact cells incubated with [32P]-orthophosphate or on ghosts incubated with [gamma-32P]ATP. Purification of Kell-Kx complex, by immunochromatography on an immobilized human monoclonal antibody of Kell blood group specificity allowed to establish that (i) neither protein is phosphorylated on tyrosine; (ii) the Kell protein is a putative substrate for Casein Kinase II (CKII) and Casein Kinase I (CKI) but not for protein kinase C (PKC), whereas Kx protein is phosphorylated by CKII and PKC but not by CKI; (iii) Protein Kinase A neither phosphorylates the Kell nor the Kx proteins. 相似文献
42.
Proximity queries such as closest point computation and collision detection have many applications in computer graphics, including computer animation, physics‐based modelling, augmented and virtual reality. We present efficient algorithms for proximity queries between a closed rigid object and an arbitrary, possibly deformable, polygonal mesh. Using graphics hardware to densely sample the distance field of the rigid object over the arbitrary mesh, we compute minimal proximity and collision response information on the graphics processing unit (GPU) using blending and depth buffering, as well as parallel reduction techniques, thus minimizing the readback bottleneck. Although limited to image‐space resolution, our algorithm provides high and steady performance when compared with other similar algorithms. Proximity queries between arbitrary meshes with hundreds of thousands of triangles and detailed distance fields of rigid objects are computed in a few milliseconds at high‐sampling resolution, even in situations with large overlap. 相似文献
43.
We present an algorithm for detecting and extracting the silhouette edges of a triangle mesh in real time using Graphical Processing Units (GPUs). We also propose a tessellation strategy for visualizing the mesh with smooth silhouettes through a continuous blend between Bézier patches with varying level of detail. Furthermore, we show how our techniques can be integrated with displacement and normal mapping. We give details on our GPU implementation and provide a performance analysis with respect to mesh size. 相似文献
44.
CD Jenkins 《Canadian Metallurgical Quarterly》1995,21(2):53-65; discussion 66-8
A detailed approach to integrating behavioral techniques into patient education, case management, and treatment evaluation of persons with diabetes mellitus is offered. The author asks a series of "what if" questions to stimulate new thinking about ways to improve patient-physician relations in overcoming problems in managing the condition, citing recent research findings in the field. Adherence to regimens, self-management, goals of an integrated diabetes program and steps along the way to achieving it, psychophysiologic mechanisms in glucose metabolism, and the function of social support are among the topics covered. 相似文献
45.
Felix Gensch Sven Gall Christoph Fahrenson Sören Müller Walter Reimers 《Journal of Materials Science》2016,51(8):3888-3896
Extrusions of hollow profiles with weld seams were conducted using the magnesium alloy ME21 applying various extrusion ratios. Subsequent analysis of the profiles’ microstructure was performed comparing weld free with weld seam containing material using (polarized) light optical microscopy (LOM). Additionally, the local texture and microstructure in the weld-free material as well as in the weld seam region has been examined with a scanning electron microscope coupled with electron backscatter diffraction technique (SEM-EBSD). The weld-free material and the weld seam are characterized by recrystallized microstructures, whereas few residual cast grains were identified. The local texture distinctively changes from the weld-free material to the weld seam. The texture of the weld-free material is comparable with the typical ME21 sheet texture. In the weld seam area, a pole density is found, which is distributed towards the transverse direction (TD) combined with a split and broadening of the pole density in the extrusion direction (ED). This texture influences the mechanical anisotropy due to the dependence of the activation of basal 〈a〉-slip and \( \{ 10\bar{1}2\} \;\langle 10\bar{1}1\rangle \)-extension twinning on the loading direction in favorably oriented grains. 相似文献
46.
Periovular granuloma formation during Schistosoma mansoni infection is a complex, multifaceted immunologic response. Products of arachidonic acid metabolism have been shown to contribute to this response through studies in which general inhibitors of lipoxygenase function reduce granulomatous inflammation. To determine which lipoxygenases are important for granuloma development in schistosomiasis, wild type mice or mice deficient for 5-lipoxygenase (5-LO) or "leukocyte-type" 12-lipoxygenase (12-LO) were infected with S. mansoni and studied for responses to schistosome eggs and egg antigens. At the acute stage of infection, when granuloma formation is usually maximal, 5-LO deficient mice developed smaller granulomas around liver-deposited schistosome eggs compared with wild type or 12-LO deficient mice. 5-LO mice also displayed less antibody-mediated (5 h) and cell-mediated, delayed-type (24 h) hypersensitivity to schistosome egg antigens than did the other two infection groups. In an attempt to determine possible mechanisms for the reduced inflammatory responses, we also measured hepatic mRNA levels of cytokines that have been shown to influence granuloma size (IL-4, IL-10, and IFN-gamma). The mRNA levels for IL-10 were significantly lower in 5-LO-deficient mice, but SEA-stimulated spleen cells did not demonstrate a significant difference in IL-10 production between wild type and 5-LO mice. These data suggest that 5-LO plays a role in host responses to schistosomiasis via a mechanism that cannot be explained solely by changes in expression of these cytokines. 相似文献
47.
Down syndrome is commonly associated with significant congenital heart disease with the potential for early development of pulmonary hypertension. As such, children with Down syndrome may be at increased risk for both perioperative and long-term mortality. The purpose of this study, using data collected from a population-based outcomes study, is to analyze the potential role that Down syndrome plays in the outcome of surgically "corrected" congenital heart disease. Data were collected from a registry of all Oregon residents who, in the period 1958 to the present, had a reparative operation for one of 14 congenital cardiac malformations when younger than 18 years (N = 3965 patients). Down syndrome was present in 289 (7%) of the total registry patients. In evaluating the cardiac mortality associated with Down syndrome for each of the repaired cardiac malformations, only complete atrioventricular septal defect was associated with significantly higher perioperative (13% vs 5%) as well as higher overall late cardiac mortality through 20 years after the operation (20% vs 5%; p = 0.04). The survival outcomes for each of the other cardiac malformations were similar for children with and without Down syndrome. 相似文献
48.
The millimeter-wave rotational spectra of 79BrNO and 81BrNO in the v2 = 1 and v3 = 2 vibrational states have been reinvestigated. Measurements of the rotational spectrum in the region of maximum c-type Coriolis interaction between the two states allowed the previous analysis to be extended to account for some uncommon effects. For the most perturbed transitions the nuclear quadrupole hyperfine structure arises from coupling of not only the bromine nucleus, but also the nitrogen nucleus with the rotational angular momentum. These effects were satisfactorily fitted with a Hamiltonian describing Coriolis coupling in a molecule with two quadrupolar nuclei. The successful analysis of pure rotational transitions then allowed accurate prediction of rovibrational transitions, six of which were measured for 79BrNO and four for 81BrNO. Copyright 1998 Academic Press. 相似文献
49.
Our knowledge in immunology has been dramatically increased by several excellent investigations elucidating the role of the Fas (Apo-1/CD95) receptor/ligand (FasL) system in complex immunological processes such as the acquisition of self tolerance in T cells, progression of autoimmunity, clonal deletion of activated T cells, B-cell regulation and the establishment of "immune privileged" sites such as testis or retina. In addition to these regulatory immunological activities, Fas/FasL interaction was also shown to participate in active defense mechanisms of the host against infected or transformed cells thereby inducing apoptosis in target cells. However, the same mechanism seems also to be part of an escape strategy utilized by tumor cells in various neoplastic malignancies of both hematopoetic as also non-hematopoetic origin. We ourselves were able to demonstrate that neoplastic plasma cell lines, as well as native malignant myeloma cells constitutively express FasL mRNA and protein. The FasL molecule is functionally active and able to induce programmed cell death in Fas sensitive target T cells in vitro. These target T cells were protected from programmed cell death by preincubation of T cells with a Fas-blocking monoclonal antibody (mAb) or of myeloma cells with a FasL-neutralizing mAb. respectively. Furthermore, overexpression of the caspase inhibitor, cowpoxvirus protein CrmA, also protected target T cells from being killed by myeloma cells, identifying Fas/FasL mediated signaling as the effector pathway utilized by malignant plasma cells. Our observations strongly suggest the engagement of Fas/FasL interaction in the escape strategy of this malignancy. The molecular basis of this evasive mechanism differs in essential respects from those described in melanoma, lung cancer, hepatocellular carcinoma, or astrocytoma, since downregulation of Fas or instrinsic insensitivity towards Fas-mediated signaling were not prerequisites for the occurrence of this phenomenon in Fas-sensitive multiple myeloma cell lines. However, myeloma cell lines resisted cocultivation with FasL-expressing target T cells in vitro. The aim of this review is to discuss the role of Fas/FasL interaction in the establishment of malignant disease, in the light of our findings on myeloma cells and also by drawing upon similar observations of other investigators on different kinds of tumor cells and cell lines and further to consider its possible relevance in formulating novel approaches to cancer therapy. 相似文献
50.
Rectal ischemia is rare because of excellent collateral supply. Although rectosigmoid ischemia is usually accompanied by more proximal colonic involvement, it may occur alone. METHODS: A retrospective review of all patients diagnosed as having colonic ischemia at the Mayo Clinic from 1976 to 1991 was performed. Clinical, endoscopic, radiological, and pathological data were obtained from patient charts. Patients with involvement of the rectosigmoid colon extending to no more than 30 cm above the dentate line on endoscopy were included in the study. A single radiologist reviewed CT scans and aortograms, and a single pathologist reviewed tissue specimens. RESULTS: Ten of 328 patients with ischemic colitis had isolated ischemic proctosigmoiditis. Six patients had acute ischemia (i.e., symptom duration of less than 4 wk), and four had chronic ischemia (symptoms for 4 wk or longer). Ischemic proctosigmoiditis affects elderly patients with atherosclerosis. An identifiable precipitating factor, such as a major illness or hemodynamic disturbance, was identified in four of six patients with acute ischemic proctosigmoiditis and in one of four patients with chronic ischemic proctosigmoiditis. CT revealed rectal wall thickening and/or perirectal stranding. Angiography may demonstrate atheromatous disease of the aortoiliac vessels. Acute and "chronic" presentations had similar histopathological changes. CONCLUSIONS: Ischemic proctosigmoiditis is rare. In contrast to generalized colonic ischemia, patients with acute rectal ischemia often have clearly identifiable precipitating factors. Conservative management is appropriate for uncomplicated acute ischemic proctosigmoiditis. Patients with chronic ischemic proctosigmoiditis. Patients with chronic ischemic proctosigmoiditis may develop bowel perforation necessitating a proctectomy or colonic diversion. Recognition of this entity and differentiation from idiopathic inflammatory bowel disease is important to determine appropriate therapy. 相似文献