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排序方式: 共有424条查询结果,搜索用时 15 毫秒
41.
Jongen R.A. Morshuis P.H.F. Guilski E. Smit J.J. Maksymiuk J. Janssen A.L.J. 《Electrical Insulation Magazine, IEEE》2006,22(6):24-35
In this article, the theoretical considerations that have to be taken into account when using statistical failure analyses of service-aged components are discussed. Furthermore, two case studies in which statistical failure analysis is used to predict future failures and to see in what way strategies can influence this prediction are included. Then, conclusions are drawn based on the analysis of the two case studies 相似文献
42.
Zhao Songzheng School of Management Northwestern Polytechnical University Xi''''an P.R.ChinaK. Smit Faculty of Aerospace Engineering Delft University of Technology Kluyverweg HS Delft 《国际设备工程与管理》1996,(1)
TheRelationshipBetweenMaintenanceandPersonnelManagementInIndustrialCompaniesZhaoSongzhengSchoolofManagementNorthwesternPolyte... 相似文献
43.
E Wenczl GP Van der Schans L Roza RM Kolb AJ Timmerman NP Smit S Pavel AA Schothorst 《Canadian Metallurgical Quarterly》1998,111(4):678-682
The question of whether melanins are photoprotecting and/or photosensitizing in human skin cells continues to be debated. To evaluate the role of melanin upon UVA irradiation, DNA single-strand breaks (ssb) were measured in human melanocytes differing only in the amount of pigment produced by culturing at two different concentrations, basic (0.01 mM) or high (0.2 mM), of L-tyrosine, the main precursor of melanin. In parallel, pheo- and total melanin contents of the cells were determined. Identical experiments were performed with two melanocyte cultures derived from a skin type I and a skin type VI individual. For the first time the correlation between UVA-induced genotoxicity and pheo-/total melanin content has been investigated. We observed that cultured in basic medium, the skin type VI melanocytes contained 10 times more total melanin and about seven times more pheomelanin than the skin type I melanocytes. Elevation of tyrosine level in the culture medium resulted in an increase of both pheo- and total melanin levels in both melanocyte cultures; however, the melanin composition of skin type I melanocytes became more pheomelanogenic, whereas that of skin type VI melanocytes remained the same. The skin type VI melanocytes cultured in basic medium demonstrated a very high sensitivity (1.18 ssb per 10(10) Da per kJ per m2) toward UVA that is probably related to their high pheo- and total melanin content. Their UVA sensitivity, however, did not change after increasing their melanin content by culturing at high tyrosine concentration. In contrast, the skin type I melanocytes demonstrated a low sensitivity (0.04 ssb per 10(10) Da per kJ per m2) toward UVA when cultured in basic medium, but increasing their melanin content resulted in a 3-fold increase in their UVA sensitivity (0.13 ssb per 10(10) Da per kJ per m2). These results demonstrate that UVA-irradiated cultured human melanocytes are photosensitized by their own synthesized chromophores, most likely pheomelanin and/or melanin intermediates. 相似文献
44.
Six patients were examined by CT following head trauma, with bleeding from the ear and trismus. The mandibular condyles were normal and MRI in two patients demonstrated a normally located meniscus. An unilateral comminuted temporal bone fracture (TBF) with multiple fracture lines and one or more fragments detached from the petrous bone was demonstrated by CT in every patient. On physical examination there was trismus, inability to chew and local pain in the temporomandibular joint (TMJ) without tenderness and swelling. Measurements of vertical and horizontal mandibular movement unequivocally demonstrated TMJ malfunction in comparison with 10 controls. The malfunction was presumably due to instability of the fractured petrous bone, base of the TMJ. Immobilising one TMJ results in blocking of both joints. Clinical improvement in 6-8 months and absence of symptoms of joint derangement on repeated physical examination were thought to be explained by restored petrous bone stability following healing of the fractures. The phenomenon of trismus following TBF with normal TMJ is rare and not yet reported. 相似文献
45.
Isolation, crystallization and preliminary crystallographic data of aspartate aminotransferase from chicken heart mitochondria 总被引:1,自引:0,他引:1
H Gehring P Christen G Eichele M Glor JN Jansonius AS Reimer JD Smit C Thaller 《Canadian Metallurgical Quarterly》1977,115(1):97-101
A series of 238 hydronephrotic kidneys in 219 children is reported. The condition was more common in the male than in the female subject and occurred more frequently on the left side. It was often bilateral, especially in infants, with an abdominal mass as the common presenting feature. Loin or abdominal pain was the most frequent complaint in older children. In some cases hydronephrosis presented as a ruptured kidney following trauma. Only 1 patient was hypertensive. The lesion was asymptomatic in 18 cases and the incidence of urinary infection was low. Dismembered pyeloureteroplasty was the procedure of choice for reconstruction. Preliminary nephrostomy was used rarely and nephrectomy was done in 10 per cent of the kidneys. Of the 7 reoperations 4 were for persistent obstruction and 3 were because stones had formed after the pyeloplasty. The late results, assessed clinically and radiologically, have been entirely satisfactory. Many kidneys of initially doubtful value showed useful improvement after reconstructive operation and no secondary nephrectomies were performed. The only death in the series occurred 2 1/2 years postoperatively and was unrelated to the urinary tract. 相似文献
46.
An intratrial proactive interference design was used to examine the nature of pigeons' memory for duration in a delayed matching task. Short (2 s) or long (10 s) target samples were preceded on test trials by a short or long presample. The durations were consistent on some trials (short-short or long-long) and inconsistent on others (short-long or long-short). Contrary to predictions based on prospective or categorical coding, accuracy was not related to duration consistency. Instead, accuracy was reduced on short-short and long-short trials and somewhat enhanced on short-long and long-long trials, suggesting that the Ss "summed across" the durations. This occurred even with a 10-s interstimulus interval (Experiment 1) and even when the presample and target sample were physically distinct (Experiment 2). Results suggest that pigeons remember event durations in an analogical and retrospective fashion. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
47.
A novel focusing and dispersive component is presented which is based on a phased array of bent optical waveguides. It combines good optical properties with small dimensions and can be realised with (high-quality) optical lithography. Applications are (de)multiplexers, wavelength filters and polarisation splitters 相似文献
48.
49.
EF Smit E Fokkema B Biesma HJ Groen W Snoek PE Postmus 《Canadian Metallurgical Quarterly》1998,77(2):347-351
Deep vein thrombosis (DVT) and pulmonary embolism (PE) are major complications associated with total knee arthroplasty. The American College of Chest Physicians recommends twice-daily, fixed-dose low-molecular-weight heparin (LMWH) as routine prophylaxis in this patient population. This study represents a cost analysis of ardeparin and enoxaparin, the two LMWHs currently available for this indication in the United States. Costs for treating DVT, PE, and major bleeding episodes were derived from values reported in the literature. Both ardeparin and enoxaparin were found to produce significant cost savings when used routinely as DVT prophylaxis after knee replacement surgery compared with no prophylaxis. Based on the currently available data, enoxaparin 40 mg once daily appears to be the least costly LMWH for routine pharmacoprophylaxis of DVT in patients undergoing knee replacement surgery. 相似文献
50.
FH Wolfhagen HJ van Hoogstraten HR van Buuren GP van Berge-Henegouwen FJ ten Kate WC Hop EW van der Hoek MJ Kerbert HH van Lijf JW den Ouden AM Smit RA de Vries RA van Zanten SW Schalm 《Canadian Metallurgical Quarterly》1998,29(5):736-742
BACKGROUND/AIMS: Treatment with ursodeoxycholic acid has been shown to decrease the rate of disease progression in patients with primary biliary cirrhosis, although the effect is modest. Since primary biliary cirrhosis has many features of an autoimmune disorder, immunosuppressives added to ursodeoxycholic acid may be of value in the treatment of primary biliary cirrhosis. METHODS: A 1-year randomized, double-blind, placebo-controlled trial was carried out in 50 patients with primary biliary cirrhosis, who had already been treated with ursodeoxycholic acid for at least 1 year, but had not achieved complete disease remission. Patients were randomized to additional prednisone (30 mg per day initially, tapered to 10 mg daily after 8 weeks) and azathioprine (50 mg daily) or placebo. A subgroup of patients received cyclical etidronate and calcium. The principal aim of the study was to assess the short-term benefits and risks of the combined bile acid and low-dose immunosuppressive regimen. Primary endpoints were effects on symptoms, liver biochemistry, liver histology, bone mass and the occurrence of adverse events. RESULTS: Pruritus (p=0.02), alkaline phosphatase, aspartate aminotransferase, IgM and procollagen-III-propeptide improved significantly (all p<0.002) in the combined treatment group as compared to the placebo group. Histological scores for disease activity and disease stage decreased significantly within the combination treatment group (p<0.001). CONCLUSIONS: In patients with primary biliary cirrhosis receiving ursodeoxycholic acid, there is an additional beneficial effect of 1-year treatment with prednisone and azathioprine on symptoms and biochemical, fibrogenetic and histological parameters. These results strongly encourage the evaluation of this triple treatment regimen in long-term controlled trials of adequate size to document its effect on clinical events. 相似文献