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排序方式: 共有898条查询结果,搜索用时 406 毫秒
101.
WD McMillan BK Patterson RR Keen VP Shively M Cipollone WH Pearce 《Canadian Metallurgical Quarterly》1995,15(8):1139-1144
Ninety-two-kilodalton type IV collagenase (MMP-9) is present in aortic aneurysms and may be important to the pathogenesis of this disease. Alteration in expression of MMP-9 or its inhibitor, the tissue inhibitor of metalloproteinase type 1 (TIMP-1), could increase degradation of extracellular matrix and lead to aneurysm formation. The purpose of this study was (1) to measure tissue levels of MMP-9 and TIMP-1 mRNA in aneurysmal (AAA), atherosclerotic occlusive (AOD), and normal (NL) human infrarenal aorta; (2) to test for their expression by cultured AAA and NL vascular smooth muscle cells (VSMCs); and (3) to locate in situ the cells responsible for mRNA production within AAA, AOD, and NL aortic wall. Total RNA extracted from AAA (n = 8), AOD (n = 8), and NL (n = 7) tissue was subjected to Northern analysis. Signals for MMP-9 and TIMP-1 were normalized to alpha-tubulin. Mean values +/- SEM were compared by ANOVA. NL and AAA VSMCs were cultured, passaged, and grown to confluence before RNA extraction and Northern analysis. In situ hybridization with digoxigenin-labeled RNA probes localized cells responsible for MMP-9 and TIMP-1 mRNA expression within sections of AAA (n = 5), AOD (n = 2), and NL (n = 2) aorta. MMP-9 mRNA levels were significantly greater in AAA (0.855 +/- 0.180) than NL (0.046 +/- 0.23) (P < .02), but differences between AOD (0.406 +/- 0.196) and AAA or AOD and NL were not significant.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
102.
An Integrated program PEELFIT is reported for the Apple IIe microcomputer, which performs pharmacokinetic analysis for intravenous and first order absorption (oral or intramuscular) data. PEELFIT, written in basic language, uses plasma concentration and time for input. Upon the user's choice, it carries out non-linear regression on the data for curve fitting, according to a one or two compartment model. the curve fitting can be done with three weighting schemes. Parameters of the plasma concentration equations are obtained from the regression analysis and further, these are employed to calculate the relevant pharmacokinetic parameters. Finally, the percentage of dose absorbed (absorbable fraction) is calculated as a function of time. various known data were analysed with PEELFIT and the results obtained confirmed its accuracy. 相似文献
103.
Cunningham Sean D.; Thomas Pamela Dixon; Warschausky Seth 《Canadian Metallurgical Quarterly》2007,52(3):331
Objective: To examine gender differences in the peer relations of children with congenital neurodevelopmental conditions (NDC). Participants: Thirty-four children with cerebral palsy or spina bifida and 41 typically developing (TD) children, ages 6-12. Measures: Personality Inventory for Children-Second Edition (PIC-2), Social Network Inventory for Children-Child Version, and the Friendship Quality Questionnaire-Revised (FQQ-R). Results: Children with NDC report smaller social networks and lower quality of friendships than TD peers. Group × Gender interaction effects were not significant. Conclusion: Prior to adolescence, the social differences and risks associated with NDC do not appear to be gender specific. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
104.
Meghan E. McGee Danielle L. Miller Seth W. Donahue 《Engineering Fracture Mechanics》2007,74(12):1942-1952
Inactivity causes bone loss, and a remobilization period that is 2-3 times longer than the disuse period is required to recover lost bone. Black bears (Ursus americanus), however, experience annual disuse (hibernation) and active periods that are approximately equal in length, but maintain bone material properties with age. Here, the effects of annual hibernation periods on whole bone properties were investigated. This study shows that mineral, geometrical and whole bone mechanical properties increase with age in black bear femurs, whereas porosity decreases with age. These results provide further support that black bears possess a biological mechanism to avoid disuse osteoporosis. 相似文献
105.
Probability of infancy problems for space launch vehicles 总被引:3,自引:1,他引:2
Seth D. Guikema M. Elisabeth Pat-Cornell 《Reliability Engineering & System Safety》2005,87(3):303-314
This paper addresses the treatment of ‘infancy problems’ in the reliability analysis of space launch systems. To that effect, we analyze the probability of failure of launch vehicles in their first five launches. We present methods and results based on a combination of Bayesian probability and frequentist statistics designed to estimate the system's reliability before the realization of a large number of launches. We show that while both approaches are beneficial, the Bayesian method is particularly useful when the experience base is small (i.e. for a new rocket). We define reliability as the probability of success based on a binary failure/no failure event. We conclude that the mean failure rates appear to be higher in the first and second flights (≈1/3 and 1/4, respectively) than in subsequent ones (third, fourth and fifth), and Bayesian methods do suggest that there is indeed some difference in launch risk over the first five launches. Yet, based on a classical frequentist analysis, we find that for these first few flights, the differences in the mean failure rates over successive launches or over successive generations of vehicles, are not statistically significant (i.e. do not meet a 95% confidence level). This is true because the frequentist analysis is based on a fixed confidence level (here: 95%), whereas the Bayesian one allows more flexibility in the conclusions based on a full probability density distribution of the failure rate and therefore, permits better interpretation of the information contained in a small sample. The approach also gives more insight into the considerable uncertainty in failure rate estimates based on small sample sizes. 相似文献
106.
107.
P Seth D Katayose Z Li M Kim R Wersto C Craig N Shanmugam E Ohri B Mudahar AN Rakkar P Kodali K Cowan 《Canadian Metallurgical Quarterly》1997,4(6):383-390
The different therapeutic options available for the treatment of chronic leukemias and myelofibrosis are discussed. In reference to chronic myeloid leukemia (CML), the choice of the most appropriate treatment must take into account not only the clinical condition but also the age of the patient. While subjects under 50 might benefit from the options offered by alpha-interferon, bone marrow and peripheral stem cell transplant, in older age groups treatment of the chronic phase must still rely on standard treatment. Chronic lymphocytic leukemia (CLL) and its variants is a disease of mostly middle and late life, with a variable clinical course. Patients show wide differences in morbidity and mortality. Many features have been shown to influence the prognosis, and the most important ones are incorporated into the staging systems currently in use. The results obtained from the study of large trials support the concept that treatment of patients with stable stage A CLL should be postponed until progression of disease. Treatment relies principally on alkylating agents, corticosteroids and radiation therapy; the new nucleoside analogues, such as fludarabine and 2-chlorodeoxyadenosine, have recently acquired established value in improving overall survival. With regard to myelofibrosis, the histological and biological features that influence the natural course of the disease are described, as well as the choice of the most appropriate treatment, which ranges from the use of alkylating agents and androgens, to splenectomy and splenic irradiation. 相似文献
108.
109.
110.
A rare case of Rhinophycomycosis entomophthora treated with a combination of Bacterium, potassium iodide and steroid is reported. Clinical features, epidemiology, mycology, and management are discussed. 相似文献