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排序方式: 共有535条查询结果,搜索用时 109 毫秒
41.
HK Atrash LT Strauss JS Kendrick FE Skjeldestad YW Ahn 《Canadian Metallurgical Quarterly》1997,89(4):512-518
The present study was conducted to elucidate the effects of tirilazad mesylate (U-74006F), a potent inhibitor of lipid peroxidation, on vessel diameter, capillary perfusion, and contractile function of rat cremaster muscle during a 90-minute reperfusion period that followed 4 hours of warm ischemia. Two groups of 32 animals were treated with either 3 mg/kg U-74006F or the vehicle (citrate buffer) alone 30 minutes before ischemia, 90 minutes after ischemia, and immediately before reperfusion. With use of intravital videomicroscopy, the internal luminal diameters of preselected vessels were measured prior to ischemia and during reperfusion. The area that filled with fluorescein was determined at 15-minute intervals for as long as 90 minutes of reperfusion, and contractile function was examined in vitro in an organ bath at that point. In the U-74006F group, after 90 minutes of reperfusion the vessel diameters returned completely to baseline and the diameters of all three categories of vessels at every time point from 10 to 90 minutes of reperfusion had significantly more rapid recovery than the controls. Although some evidence of more rapid fluorescence was noted in the U-74006F group, the two groups did not differ significantly at any time period of reperfusion. In response to tetanic stimulation, the muscles treated with U-74006F had a significantly greater contractile force at all stimulation frequencies than the control muscles. Our findings indicate that pretreatment with U-74006F can effectively decrease the rise of vascular resistance and preserve the contractile function of skeletal muscle during early reperfusion, thereby attenuating ischemia-reperfusion injury. 相似文献
42.
Watson David; Clark Lee Anna; Weber Kris; Assenheimer Jana Smith; Strauss Milton E.; McCormick Richard A. 《Canadian Metallurgical Quarterly》1995,104(1):15
L. A. Clark and D. Watson (1991) proposed a tripartite model of depression and anxiety that divides symptoms into 3 groups: symptoms of general distress that are largely nonspecific, manifestations of anhedonia and low positive affect that are specific to depression, and symptoms of somatic arousal that are relatively unique to anxiety. This model was tested by conducting separate factor analyses of the 90 items in the Mood and Anxiety Symptom Questionnaire (D. Watson & L. A. Clark, 1991) in 5 samples (3 student, 1 adult, 1 patient). The same 3 factors (General Distress, Anhedonia vs. Positive Affect, Somatic Anxiety) emerged in each data set, suggesting that the symptom structure in this domain is highly convergent across diverse samples. Moreover, these factors broadly corresponded to the symptom groups proposed by the tripartite model. Inspection of the individual item loadings suggested some refinements to the model. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
43.
Plasma Analysis and Thin Film Properties of Sputter‐ and Ionplating PVD‐Processes For a large number of thin film applications just few thin film coating processes are used in industrial scale production. For example, Magnetron Sputtering (MS), Ionplating (IP), Arc Source Ablation (AS) and technical variations of them. Recent developments allow beside traditional dc modes also the use of pulsed dc modes, as for instance in magnetron sputtering and arc source deposition. In this work the Reactive Low Voltage Ionplating (RLVIP) with pulsed substrate bias (Ionplating Plasma Assisted IPPA), DC and DC‐pulse Magnetron Sputtering and Arc source deposition in DC‐ and DC‐pulse mode is of interest concerning their plasma. Pulsing the substrate‐bias of the RLVIP (IPPA) influences film stress and optical absorption but is not easy to handle in industrial production. Pulsing the sputter processes leads to massive changes in the coating plasma and the coatings itself. And finally pulsing the arc‐current of the Arc Source Ablation processes implements advantages for lower cathode temperatures, for use of less conducting cathode materials, less droplet formation and improved chemical reactivity with oxygen. 相似文献
44.
Glass welding by ultrashort laser pulses allows joining without the need of an absorber or a preheating and postheating process. However, cracks generated during the welding process substantially impair the joining strength of the welding seams. In this paper a sample preparation method is described that prevents the formation of cracks. The measured joining strength of samples prepared by this method is substantially higher than previously reported values. 相似文献
45.
The authors analyzed death rates from external causes (accidents, injuries, homicides, etc.) for persons with developmental disability in California. There were 520 such deaths during the 1981-1995 study period, based on 733,705 person-years of exposure; this represents all persons who received any services from the state. Compared with the general California population, persons with developmental disability were at lower risk of homicide, suicide, and poisonings (standardized mortality ratios, 0.31-0.68), but higher risk of pedestrian accidents, falls, fires, and, especially, drowning (standardized mortality ratio=6.22). A major focus of the study was comparisons between different residential settings. Persons in semi-independent living had significantly higher risk than did those in their family home or group homes, with homicides rates being three times higher and pedestrian accidents rates being doubled, while persons in institutions had much lower risks with respect to most causes. Of the 28 deaths due to drug and medication overdoses, 79 percent occurred in supported living or small-group homes. Avoidable deaths could be reduced by making direct care staff more aware of the risks and better trained in acute care, along with improved monitoring of special incidents. 相似文献
46.
Chip multiprocessors with thread-level speculation have become the subject of intense research. This work refutes the claim that such a design is necessarily too energy inefficient. In addition, it proposes out-of-order task spawning to exploit more sources of speculative task-level parallelism. 相似文献
47.
KD Heckman GJ Weiner CS Davis RG Strauss MP Jones CP Burns 《Canadian Metallurgical Quarterly》1997,15(3):1143-1149
PURPOSE: We designed and conducted a randomized single-institution trial comparing two common prophylactic platelet transfusion thresholds in patients undergoing induction therapy for acute leukemia. PATIENTS AND METHODS: Seventy-eight patients undergoing induction therapy for acute leukemia were randomized to receive prophylactic apheresis platelet concentrates when the platelet count was either < or = 10,000/microL or < or = 20,000/microL. RESULTS: There was no significant difference in the total number of bleeding episodes per patient with a median of four in the < or = 10,000/microL arm and two in the < or = 20,000/microL arm (25th to 75th percentiles of 2, 7 and 1, 5, respectively; P = .12). Patients randomized to the < or = 10,000/microL arm received more platelet transfusions for bleeding [one (0, 2) v zero (0, 0); P = .0003]. In contrast, patients on the < or = 20,000/microL arm received more platelet transfusions for prophylactic indications [10 (5, 14) v six (3, 8); P = 0.001], as would be expected, but less for bleeding. Nevertheless, the total number of platelet transfusions given to patients on the < or = 20,000/microL arm was higher and nearly significant [11 (6, 15) v seven (5, 11); P = .07]. There were no statistically significant differences between the groups with regard to RBC transfusion requirements, febrile days, days hospitalized, days thrombocytopenic, need for HLA-matched platelets, remission rate, or death during induction chemotherapy. No patient in either group died from hemorrhage or underwent major surgery for bleeding complications. CONCLUSION: Giving prophylactic platelets at a threshold of < or = 10,000/microL compared with < or = 20,000/microL can decrease the total utilization of platelets with only a small adverse effect on bleeding, and no statistically significant effect on morbidity. 相似文献
48.
DJ Kwiatkowski DH Harpole J Godleski JE Herndon DB Shieh W Richards R Blanco HJ Xu GM Strauss DJ Sugarbaker 《Canadian Metallurgical Quarterly》1998,16(7):2468-2477
PURPOSE: To retrospectively construct a comprehensive multivariate model of cancer recurrence and to design a molecular pathologic substaging system in stage I non-small-cell lung cancer (NSCLC). METHODS: All patients with stage I NSCLC resected at Brigham and Women's Hospital (Boston, MA) between 1984 and 1992 with adequate clinical follow-up were studied. The importance of three demographic characteristics, surgical extent, 11 pathologic features, and seven molecular factors on cancer-free survival was examined. RESULTS: Two hundred forty-four patients were studied, with 25 noncancer deaths and 80 patients with recurrent disease. Significant univariate predictors (P < .05) of cancer recurrence were age older than 60 years, male sex, wedge resection, World Health Organization (WHO) adenocarcinoma subtype solid tumor with mucin, lymphatic invasion, and p53 expression. Multivariate analysis identified nine independent predictors of recurrence: solid tumor with mucin, a wedge resection, tumor diameter of 4 cm or greater, lymphatic invasion, age older than 60 years, male sex, p53 expression, K-ras codon 12 mutation, and absence of H-ras p21 expression. Multivariate cancer-free survival (CFS) analysis in the 180 patients who underwent lobectomy or pneumonectomy led to the elimination of sex and age, which left six independent factors. CONCLUSION: Lobectomy or pneumonectomy should be performed in stage I NSCLC. Using the six independent factors for recurrent disease, we propose a pathologic molecular substaging system. Patients with two factors or less are graded Ia, with a 5-year CFS rate of 87%; those with three factors are graded Ib, with a 5-year CFS rate of 58%; and those with four factors or more are graded Ic, with a 5-year CFS rate of 21%. 相似文献
49.
OBJECTIVE: This retrospective analysis was designed to optimize the parameters and techniques required to successfully perform high-quality coincidence imaging in a general nuclear medicine department using a dual-headed gamma camera. METHOD: Coincidence imaging was performed on 33 patients after an intravenous injection of 3.0-5.0 mCi fluoro-2-deoxyglucose (18F-FDG). Data for all subjects were evaluated to determine which technical considerations contributed to an overall improvement in image quality. RESULTS: After reviewing the data for the 33 subjects, several modified techniques were implemented and parameters were adjusted that enhanced the overall quality of the images. The extremely short half-life of 18F restricts the opportunity to repeat studies that were delayed, interrupted or technically substandard. CONCLUSION: The review of the data indicated that strict adherence to protocol is necessary to achieve optimal results while attempting to incorporate this new imaging modality into a typical nuclear medicine department. 相似文献
50.
AY Tien WW Eaton TE Schlaepfer IK McGilchrist R Menon R Powers E Aylward P Barta ME Strauss GD Pearlson 《Canadian Metallurgical Quarterly》1996,19(2-3):93-101
Much of the literature shows various regional structural brain abnormalities in schizophrenia, but the complexity and variability of brain makes it difficult to determine how these regions are related. Statistical methods which estimate factors underlying patterns of covariance have not been widely used, but could be useful for analyzing such complex data. We applied exploratory and confirmatory factor analysis procedures to specific cortical and subcortical regional brain volume measures from MRI data in 60 normal and 44 schizophrenic subjects. Basal ganglia, heteromodal cortical gray, and medial temporal lobe factors were present in both the normal and the schizophrenia groups. The factor structure observed in the normal group showed a high degree of bilateral symmetry which is present but disrupted in the schizophrenia group. In the bilateral data, the disruption is most pronounced with medial and lateral temporal lobe structures including entorhinal cortex and anterior and posterior superior temporal gyri. There was a significant correlation between the basal ganglia factor and the heteromodal cortical gray factor in the normal group that was not present in the schizophrenia group. In the unilateral data, left posterior superior temporal gyrus did not load onto any factor in the schizophrenia group. Confirmatory factor analyses showed significant differences between the two groups in factor structure. A number of specific brain regions are affected in schizophrenia, and structural relationships between groups of regions also are abnormal. The results suggest that heteromodal dorsolateral prefrontal and superior temporal cortical gray regions are structurally related, whereas inferior parietal cortical gray is less so. These results should be viewed as preliminary as the ratio of parameters to subjects was relatively low, and replication is needed. However, the results demonstrate the potential utility of latent structure methods such as factor analysis in study of complex relationships in neuropsychiatric data. 相似文献