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排序方式: 共有323条查询结果,搜索用时 15 毫秒
1.
In this paper the results are presented of a test program on the energy absorption of composite cylinders loaded in compression. The influence of the laminate lay-up and of the trigger configuration were determined. Two different failure modes for the different laminates and triggers were observed: a splaying mode and a fragmentation mode. The splaying mode is more efficient in absorbing energy. The failure mode did not change during the crushing process. 相似文献
2.
Karin Metz Stephanie Fl?ter Christoph Kr?ger Carolin Donath Daniela Piontek Sabine Gradl 《Nicotine & tobacco research》2007,9(8):853-863
Smokers with smoking-related diseases who are hospitalized in rehabilitation centers should be offered smoking cessation. This is the first study evaluating whether telephone booster sessions after intensive inpatient treatment are an effective strategy. The present study was conducted in 13 rehabilitation centers for somatic disorders as a prospective multicenter study with a randomized treatment-control group design. We compared abstinence rates after hospital discharge from treatment that included a group smoking cessation program with (treatment group) and without telephone booster sessions (control group). Data from 290 smokers were analyzed. After 6 and 12 months the treatment group achieved abstinence rates twice as high as those of the control group. Men profited more from telephone booster sessions than did women. Results indicated that telephone booster sessions were highly effective (even) after an inherently intensive group program during a hospital stay. Further research should focus on the special needs of women receiving telephone counseling. 相似文献
3.
For pt.1 see ibid., vol.9, no.3, p.68-72 (2005). Part I of this series discussed a solution for running multiprotocol label switching virtual private networks (MPLS VPNs) across a service provider's native IP network. Yet, MPLS VPNs support only unicast routing, whereas many of the enterprise customers that use the service run applications that require IP multicast. This article examines multicastVPN (mVPN), which provides the ability to support IP multicast across MPLS VPNs. Service providers can thus offer IP VPN services that support unicast and multicast applications. 相似文献
4.
R Kath K H?ffken C Otte K Metz ME Scheulen F Hülskamp S Seeber 《Canadian Metallurgical Quarterly》1993,4(7):585-590
Patients with non-cardiac chest pain (NCCP) (n = 387) and cardiac chest pain (CCP) (n = 93) were compared with community controls (n = 81), using a symptom questionnaire that assessed the presence of irritable bowel syndrome (IBS), functional dyspepsia, and oesophageal dysfunction and chest pain characteristics. A significantly (p < 0.05) increased prevalence of symptoms compatible with IBS occurred in NCCP patients when compared with those with CCP and with controls. Dysphagia was more frequent in both those with non-cardiac and cardiac chest pain than in controls; this was not apparent, however, when patients with concomitant IBS were excluded. The presence of oesophageal or gastrointestinal symptoms did not enable discrimination with regard to the chest pain characteristics. We conclude that unselected referred patients with documented NCCP are more likely to have IBS and that the presence of oesophageal symptoms such as dysphagia may merely reflect the spectrum of the 'irritable gut'. 相似文献
5.
J Chesney C Metz AB Stavitsky M Bacher R Bucala 《Canadian Metallurgical Quarterly》1998,160(1):419-425
We recently described a novel population of blood-borne cells, termed fibrocytes, that display a distinct cell surface phenotype (collagen+/CD13+/CD34+/CD45+), rapidly enter sites of tissue injury, and contribute to scar formation. To further characterize the role of these cells in vivo, we examined the expression of type I collagen and cytokine mRNAs by cells isolated from wound chambers implanted into mice. Five days after chamber implantation, CD34+ fibrocytes but not CD14+ monocytes or CD90+ T cells expressed mRNA for type I collagen. Fibrocytes purified from wound chambers also were found to express mRNA for IL-1beta, IL-10, TNF-alpha, JE/MCP, MIP-1alpha, MIP-1beta, MIP-2, PDGF-A, TGF-beta1, and M-CSF. The addition of IL-1beta (1-100 ng/ml), a critical mediator in wound healing, to fibrocytes isolated from human peripheral blood induced the secretion of chemokines (MIP-1alpha, MIP-1beta, MCP-1, IL-8, and GRO alpha), hemopoietic growth factors (IL-6, IL-10, and macrophage-CSF), and the fibrogenic cytokine TNF-alpha. By contrast, IL-1beta decreased the constitutive secretion of type I collagen as measured by ELISA. Additional evidence for a role for fibrocytes in collagen production in vivo was obtained in studies of livers obtained from Schistosoma japonicum-infected mice. Mouse fibrocytes localized to areas of granuloma formation and connective matrix deposition. We conclude that fibrocytes are an important source of cytokines and type I collagen during both the inflammatory and the repair phase of the wound healing response. Furthermore, IL-1beta may act on fibrocytes to effect a phenotypic transition between a repair/remodeling and a proinflammatory mode. 相似文献
6.
JH Noseworthy P O'Brien BJ Erickson D Lee D Sneve GC Ebers GP Rice A Auty WJ Hader A Kirk P Duquette J Carter G Francis L Metz E Shuster 《Canadian Metallurgical Quarterly》1998,51(5):1342-1352
OBJECTIVE: To determine whether sulfasalazine is better than placebo in slowing disability progression in MS. METHODS: In this randomized, double-blind, placebo-controlled phase III trial, 199 patients with active relapsing-remitting (n = 151) or progressive (n = 48) MS were evaluated at 3-month intervals for a minimum of 3 years (94% completed 3 years of follow-up; mean follow-up, 3.7 years). MRI studies were performed at 6-month intervals on a subset of 89 patients. RESULTS: Sulfasalazine failed to slow or prevent disability progression as measured by the primary outcome (confirmed worsening of the Expanded Disability Status Scale [EDSS] score by at least 1.0 point on two consecutive 3-month visits). Sulfasalazine influenced favorably a number of secondary outcomes during the first 18 months of the trial (e.g., annualized relapse rate, proportion of relapse-free patients; progressive subgroup only: rate of EDSS progression at 1 and 2 years, median time to EDSS progression) but these positive findings were not sustained into the second half of the trial. CONCLUSIONS: Sulfasalazine does not prevent EDSS score progression in the subset of MS patients studied by this protocol. Treatments may improve relapse-related outcomes in MS, at least temporarily, without providing sustained slowing of EDSS progression. Phase III MS trials should be of sufficient length to determine a meaningful impact on disease course. 相似文献
7.
GM Ribbers WP Oosterhuis J van Limbeek M de Metz 《Canadian Metallurgical Quarterly》1998,79(12):1549-1552
OBJECTIVE: Evaluation of immune system function in patients with reflex sympathetic dystrophy (RSD). DESIGN: Survey on blood samples obtained from RSD patients and from a randomly selected control group. The lymphocyte populations (T, B, NK cells), and the activated T cells (CD25, and HLA-Dr-positive CD4 and CD8 cells) were analyzed by flow cytometry with dual-color direct immunofluorescence after whole-blood lysis. Clinical chemistry parameters were analyzed in additional serum samples. SETTING: Tertiary care center (outpatient rehabilitation clinic). SUBJECTS: Thirteen patients (nine women) with RSD and a control group of 21 healthy individuals. MAIN OUTCOME MEASURES: The results of the flow cytometry analysis of RSD patients were related to those of the control subjects. Means were analyzed, and confidence intervals for differences of the means were calculated. The means of the clinical chemical analysis were related to local reference values. RESULTS: The flow cytometry analysis did not differ between RSD patients and healthy controls. Although in some patients an individual parameter of clinical chemical analysis differed from its reference value, all of the mean values were within reference limits. Stratification on medications with immunomodulatory effects and on probability of a definite diagnosis of RSD had no influence on the results. CONCLUSION: No association between immunologic indices and RSD was found. This finding is relevant, because recent theories stress that it is not the sympathetic nervous system but a local inflammatory reaction that is fundamental in the pathogenesis of RSD. The results of this study do not support this theory. 相似文献
8.
Single-phase nickel manganite spinels, Ni
x
Mn3–x
O4, with 0.5 x 1, were prepared by a careful thermal processing of nickel-manganese coprecipitated oxalate precursors. Powder X-ray diffraction analysis of the spinel revealed the presence of cubic single spinel phase with parametera which decreases with nickel content. The lattice parameter variation can be explained in terms of the distribution of Ni2+ ions on the octahedral sites. Therefore, a fine analysis of data shows that some Ni2+ ions (forx>0.56) are located in tetrahedral sites. The percentage of nickel in A-sites increases with nickel content (x) following the relation % Ni2+ in A sites =P = – 82.1x
2+192.4x–81.5 and thus the general formula for cation distribution is
相似文献
9.
A. Tropmann N. Lass N. Paust T. Metz C. Ziegler R. Zengerle P. Koltay 《Microfluidics and nanofluidics》2012,12(1-4):75-84
This study presents a new, simple and robust, pneumatically actuated method for the generation of liquid metal micro droplets in the nano- to picoliter range. The so-called StarJet dispenser utilizes a star-shaped nozzle geometry that stabilizes liquid plugs in its center by means of capillary forces. Single droplets of the liquid metal can be pneumatically generated by the interaction of the sheathing gas flow in the outer grooves of the nozzle and the liquid metal. For experimental validation, a print head was build consisting of silicon chips with a star-shaped nozzle geometry and a heated actuator (up to 280°C). The silicon chips are fabricated by Deep Reactive Ion Etching (DRIE). Chip designs with different star-shaped geometries were able to generate droplets with diameters in the range of the corresponding nozzle diameters. The StarJet can be operated in two modes: Either continuous droplet dispensing mode or drop on demand (DoD) mode. The continuous droplet generation mode for a nozzle with 183?μm diameter shows tear-off frequencies between 25 and 120?Hz, while droplet diameters remain constant at 210?μm for each pressure level. Metal columns were printed with a thickness of 0.5–1.0?mm and 30?mm height (aspect ratio >30), to demonstrate the directional stability of droplet ejection and its potential as a suitable tool for direct prototyping of the metal microstructures. 相似文献
10.
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