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排序方式: 共有293条查询结果,搜索用时 15 毫秒
191.
L Simpson SH Wang OH Thiemann JD Alfonzo DA Maslov HA Avila 《Canadian Metallurgical Quarterly》1998,26(1):170-176
To study effort tolerance in elderly women with different physical activity backgrounds, 52 physically active (PA) and 42 sedentary control women (CO) aged 66-85 yr were assigned to perform cycle ergometer exercise to their volitional maximum. Oxygen uptake, respiratory exchange ratio (RER), heart rate, work power, and rate pressure product were measured to evaluate the severity of exercise. Plasma C-ANP (C-terminus of the atrial natriuretic peptide prohormone) and plasma N-ANP (N-terminus of the atrial natriuretic peptide prohormone) were analyzed as indicators of cardiac load. Eighty-one percent (N = 42) of the PA and 52% (N = 22) of CO performed the ergometer exercise. The mean peak oxygen uptake was 22.6 and 15.1 mL x kg(-1) x min(-1) among PA and CO, respectively. Twenty-two of the 42 PA and 19 of the 22 CO terminated the ergometer exercise before attaining the objective maximum. The most common reasons for termination were the subject's own wish, abnormal cardiovascular response, or lower limb tiredness. Both C-ANP and N-ANP increased after exercise. The increase in plasma C-ANP correlated significantly with a few physiological variables, whereas comparable associations with N-ANP were not found. It is concluded that inexperience of physical exertion and medical as well as physiological factors limit effort tolerance among elderly women. Differences in the response of C-ANP and N-ANP were found that are suggested to be due to differences in the postsecretory mechanisms between these hormones. 相似文献
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OH Gr?hn JA Lukkarinen JM Oja PC van Zijl JA Ulatowski RJ Traystman RA Kauppinen 《Canadian Metallurgical Quarterly》1998,18(8):911-920
STUDY DESIGN: Consecutive case retrospective chart review. OBJECTIVES: First, to assess whether the number of' patients requiring a second cervical surgical intervention was changed as a result of using anterior cervical plate stabilization, and second, to determine the additional risks and/or benefits associated with the hardware implantation. SUMMARY OF BACKGROUND DATA: The optimal technique of performing stabilization, arthrodesis, and alignment of a cervical segment after discectomy with neural decompression in degenerative disease has yet to be determined. METHODS: The charts of 402 patients who had undergone an anterior cervical discectomy and arthrodesis for degenerative disease performed both with and without anterior cervical plate stabilization were reviewed, and reoperation data were compiled. The average follow-up time was 3.8 years (range, 1.5-9.4 years). RESULTS: Of 365 patients with 1- or 2-level cervical arthrodesis, 22 required a second surgical intervention (20 bone alone, 2 with anterior cervical plate stabilization). The Log-Rank test, which uses all patients and their total follow-up periods, was statistically significant favoring anterior cervical plate stabilization at one and two levels (P = 0.015). CONCLUSIONS: The addition of anterior cervical plate stabilization in one- and two-level cervical degenerative disease supplements the internal stabilization initially provided by the bone graft, and yields a lower reoperation rate. 相似文献
196.
A novel cell surface phosphoinositide-cleaving phospholipase C (ecto-PLC) activity was isolated from cultured cells by exploiting its presumed external exposure. Biotinylation of intact cells followed by solubilization of the biotinylated proteins from a membrane fraction and recovery onto immobilized-avidin beads, allowed assay of this cell surface enzyme activity apart from the background of the substantial family of intracellular PLCs. Several cell lines of differing ecto-PLC expression were examined as well as cells stably transfected to overexpress the glycosylphosphatidylinositol (GP) anchored protein human placental alkaline phosphatase (PLAP) as a cell surface enzyme marker. The resulting bead preparations from ecto-PLC positive cells possessed calcium-dependent PLC activity with preference for lysophosphatidylinositol (lysaPI) rather than phosphatidylinositol (PI). The function of ecto-PLC of intact cells evidently is not to release GPI-anchored proteins at the cell surface, as no detectable Ca(2+)-dependent release of overexpressed PLAP from ecto-PLC-positive cells was observed. To investigate the cell surface linkage of the ecto-PLC itself, intact cells were treated with bacterial PI-PLC to cleave simple GPI anchors, but no decrease in ecto-PLC activity was observed. High ionic strength washes of biotinylated membranes prior to the generation of bead preparations did not substantially reduce the lysoPI-PLC activity. The results verify that the ecto-PLC is truly cell surface-exposed, and unlike other members of the PLC family that are thought to be peripheral membrane proteins, this novel lysoPI-PLC is most likely a true membrane protein. 相似文献
197.
Characteristics and reproducibility of bulbocavernosus reflex (BCR) and pudendal somatosensory evoked potentials (PSEP) elicited by mechanical stimulation in children were tested. Twenty-five male children aged 5-14 years without uroneurological complaints were enrolled in the study. In addition to electrical stimulation, a specially constructed electromechanical hammer triggered by an oscilloscope was used for mechanical stimulation of distal penis. All responses were detected by surface electrodes. The latencies and amplitudes of averaged as well as latencies of single BCR on single and double electrical stimuli were determined. Mechanical stimulation was described as much less unpleasant than electrical stimulation. Both mechanical/electrical stimulation elicited consistent and reproducible responses in high percentages of children (BCR: average, 80%/71%, single, 94%/100%; PSEP: 96%/96%, respectively). BCR latencies were significantly longer and PSEP amplitudes were significantly higher on mechanical stimulation. The compliance with mechanical was much better than with the electrical stimulation and the former can be recommended for clinical use. The effective mechanical stimulus delivered by a particular mechanical stimulator has a characteristic 'delay' (as to the actual point of triggering the oscilloscope ray) which influences the latency reading of responses; appropriate control data are therefore necessary. 相似文献
198.
M MacDougall D Simmons A Dodds C Knight X Luan M Zeichner-David C Zhang OH Ryu Q Qian JP Simmer CC Hu 《Canadian Metallurgical Quarterly》1998,77(12):1970-1978
Tuftelin is a protein that has been suggested to function during enamel crystal nucleation. Published sequences for bovine tuftelin cDNA and genomic clones proposed different reading frames that radically affected the derived amino acid sequence of the tuftelin carboxyl-terminus. We have isolated and characterized a full-length mouse cDNA clone and a partial porcine cDNA clone that include the region of the proposed frame-shift. The mouse tuftelin clone is 2572 nucleotides in length, exclusive of the poly(A+) tail. Translation from the 5'-most ATG yields a protein of 390 amino acids with an isotope-averaged molecular mass of 44.6 kDa and an isoelectric point of 5.9. Comparison of the bovine, mouse, and porcine cDNAs supports the revised bovine tuftelin amino acid sequence and suggests that the bovine tuftelin translation initiation codon be re-assigned to a more 5' ATG. Re-assigning the translation initiation codon lengthens the tuftelin protein by 52 amino acids, 51 of which are identical between bovine and mouse. At the carboxyl-terminus, the revised bovine and the mouse sequences match at 39 of the final 42 amino acid positions, compared with 2 identities with the originally published bovine reading frame. Northern blot analysis reveals that tuftelin is not ameloblast-specific but is expressed in multiple tissues, including kidney, lung, liver, and testis. Two tuftelin RNA messages, of 2.6 and 3.2 kb, were detected. DNA sequence characterization of an RT-PCR amplification product confirmed expression of tuftelin in kidney, and identified an alternatively spliced mouse tuftelin mRNA lacking exon 2. 相似文献
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TAE‐KWANG SONG JI‐SOO KIM CHANG‐YOUNG OH YUN‐JAE KIM CHI‐YONG PARK KYOUNG‐SOO LEE 《Fatigue & Fracture of Engineering Materials & Structures》2011,34(8):624-641
This paper provides approximate expressions for through‐wall welding residual stresses in dissimilar metal nozzle butt welds of pressurized water reactors. An idealized shape of nozzle is proposed, based on which systematic elastic–plastic thermo‐mechanical finite element analyses are conducted by varying the thickness and radius of the nozzle and the length of the safe‐end. Based on the results, a through‐wall welding residual stress profile for dissimilar metal nozzle butt welds is proposed by modifying the existing welding residual stress profile for austenitic pipe butt welds in the R6 procedure. 相似文献