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1.
JD Aubert B Carnal J Ricou P Fioroni L Juillerat-Jeanneret F Pinet 《Canadian Metallurgical Quarterly》1998,11(2-3):209-213
Biosynthesis of active endothelin-1 (ET-1) implies an enzymatic processing of the inactive precursor Big ET-1 (1-39) into the mature, 21 amino acid peptide. The aim of this study was to characterize in airway and alveolar epithelial cells the enzymes responsible for this activation. BEAS-2B and A549 cells, which both produce ET-1, were studied in vitro as models for bronchiolar and alveolar cells, respectively. Both cell lines were able to convert exogenously added Big ET-1 (0.1 microM) into ET-1, suggesting a cell surface or an extracellular processing. The conversion was inhibited by phosphoramidon in both cell lines with an IC50 approximately 1 microM, but not by thiorphan, a specific inhibitor of neutral endopeptidase 24.11 (NEP). The endogenous production of serum-stimulated BEAS-2B and A549 cells was not inhibited by thiorphan, and phosphoramidon showed inhibition only at high concentration (>100 microM). Western blotting following electrophoresis in reducing conditions demonstrated a protein of MR 110 corresponding to the ECE-1 monomer in both BEAS-2B and A549 cells, as well as in whole lung extracts. By RT-PCR we revealed the mRNA encoding for the ECE-1b and/or -1c subtype, but not ECE-1a, in both cell lines. We conclude that BEAS-2B and A549 cells are able to process either endogenous or exogenous Big ET-1 by ECE-1 and that isoforms 1b and 1c could be involved in this processing with no significant role of NEP. 相似文献
2.
This work begins with a summary of the characteristics of electromagnetic casting and the present knowledge of the subject.
Also described is the use of new local measurement techniques for velocity, magnetic field, current density, and phase difference,
which allow experimental investigation of the flow of molten metal in industrial equipment (up to 700 °C) in the presence
or absence of an induction magnetic field. Next, these methods are applied to the study of electromagnetic and hydrodynamic
phenomena, inside the sumps of both rectangular and circular cross-section ingots of aluminum alloys cast in electromagnetic
molds. The important shield effect as a function of the screen location is studied by means of a mercury pool simulating electromagnetic
casting. 相似文献
3.
J. L. Meyer J. Szekely N. El-Kaddah C. Vivès R. Ricou 《Metallurgical and Materials Transactions B》1987,18(3):539-548
A mathematical formulation has been developed to represent the electromagnetic force field and the velocity field in the melt
for the electromagnetic casting of aluminum. The theoretical predictions based on fundamental considerations are compared
with experimental measurements obtained on a physical model system. The measurements and predictions were found to be in good
agreement, regarding both the velocity fields and the electromagnetic force fields. The principal conclusion emerging from
this work is of critical importance in achieving the dual objective, that is providing a restraining force, while minimizing
the melt velocity perpendicular to the free surface. The mathematical formulation presented in the paper provides the theoretical
framework for quantitatively defining these conditions in terms of the coil and the shield parameters.
J.L. Meyer, formerly with the Department of Materials Science and Engineering at Massachusetts Institute of Technology
N. EL-KADDAH, formerly with the Department of Materials Science and Engineering at MIT 相似文献
4.
P Jolliet DO Slosman B Ricou PM Suter JC Chevrolet 《Canadian Metallurgical Quarterly》1995,21(9):723-728
We report the results of a longitudinal study aimed at better defining concomitant changes of both bone mineral density (BMD) and of four independent markers of bone turnover (serum osteocalcin, serum alkaline phosphatase activity, fasting urinary hydroxyproline/creatinine and calcium/creatinine ratio) following natural menopause. The results obtained indicate that, within a relatively short period of time since cessation of gonadal function, conventional markers of bone turnover behave differently. In fact, while the mean values of hydroxyproline/creatinine ratio (felt to be a marker of bone resorption) rise immediately at the first control (19.7 +/- 11.7 months), the bone formation markers gradually increase and, as far as serum osteocalcin levels are concerned, this increment appears to be long-lasting. As a result of these changes, a negative skeletal balance follows, which is documented by the prolonged reduction of bone mineral density during the entire observation period. Mean +/- SD % measured yearly bone loss was -2.83 +/- 2.6. There was a highly significant correlation between initial and final BMD values (r = 0.908, p < 0.001; r2 = 82.5) and a weak inverse correlation (r = -0.298, p < 0.046) between initial serum alkaline phosphatase values and % yearly bone loss. In conclusion, measurement of the biological indices of bone remodelling following natural menopause indicate that the increase in osteogenesis is delayed compared to that of bone resorption; furthermore, in the immediate postmenopausal period, the actual bone mass should be considered the best predictor of future bone mass. The inverse correlation found between % yearly bone loss and serum alkaline phosphatase values seems to emphasize the importance of increased bone turnover as an independent predictor of bone loss. 相似文献
5.
New measurement techniques for local velocity, magnetic field, and current density have been applied to the study of electromagnetic
and hydrodynamic phenomena in a coreless induction furnace containing an aluminum alloy. The action of electromagnetic shields
on the intensity and the structure of the liquid metal flow is reported. It is shown that the direction of the fluid flow
and the number and sizes of the recirculating cells may be significantly modified; the electromagnetic stirring may also be
practically canceled. The influence of the dimensions of the screens on the structure of the liquid metal flow is examined.
Finally, the modification of the fluid flow phenomena is explained by the evolution of the electromagnetic force patterns. 相似文献
6.
7.
C Jaccard N Troillet S Harbarth G Zanetti D Aymon R Schneider R Chiolero B Ricou J Romand O Huber P Ambrosetti G Praz D Lew J Bille MP Glauser A Cometta 《Canadian Metallurgical Quarterly》1998,42(11):2966-2972
Nosocomial pneumonia and acute peritonitis may be caused by a wide array of pathogens, and combination therapy is often recommended. We have previously shown that imipenem-cilastatin monotherapy was as efficacious as the combination of imipenem-cilastatin plus netilmicin in these two settings. The efficacy of imipenem-cilastatin is now compared to that of piperacillin-tazobactam as monotherapy in patients with nosocomial pneumonia or acute peritonitis. Three hundred seventy one patients with nosocomial pneumonia or peritonitis were randomly assigned to receive either imipenem-cilastatin (0.5 g four times a day) or piperacillin-tazobactam (4.5 g three times a day). Three hundred thirteen were assessable (154 with nosocomial pneumonia and 159 with peritonitis). For nosocomial pneumonia, clinical-failure rates in the piperacillin-tazobactam group (13 of 75 [17%]) and in the imipenem-cilastatin group (23 of 79 [29%]) were similar (P = 0.09), as were the numbers of deaths due to infection (6 in the imipenem-cilastatin group [8%], 7 in the piperacillin-tazobactam group [9%]) (P = 0.78). For acute peritonitis, clinical success rates were comparable (piperacillin-tazobactam, 72 of 76 [95%]; imipenem-cilastatin, 77 of 83 [93%]). For infections due to Pseudomonas aeruginosa, 45 patients had nosocomial pneumonia (21 in the piperacillin-tazobactam group and 24 in the imipenem-cilastatin group) and 10 had peritonitis (5 in each group). In the patients with nosocomial pneumonia, clinical failure was less frequent in the piperacillin-tazobactam group (2 of 21 [10%]) than in the imipenem-cilastatin [corrected] group (12 of 24 [50%]) (P = 0.004). Bacterial resistance to allocated regimen was the main cause of clinical failure (1 in the piperacillin-tazobactam group and 12 in the imipenem-cilastatin group). For the patients with peritonitis, no difference in clinical outcome was observed (five of five cured in each group). The overall frequencies of adverse events related to treatment in the two groups were similar (24 in the piperacillin-tazobactam group, 22 in the imipenem-cilastatin group). Diarrhea was significantly more frequent in the piperacillin-tazobactam group (10 of 24) than in the imipenem-cilastatin group (2 of 22). This study suggests that piperacillin-tazobactam monotherapy is at least as effective and safe as imipenem-cilastatin monotherapy in the treatment of nosocomial pneumonia or peritonitis. In P. aeruginosa pneumonia, piperacillin-tazobactam achieved a better clinical efficacy than imipenem-cilastatin, due to reduced development of microbiological resistance. Tolerance was comparable, with the exception of diarrhea, which was more frequent with piperacillin-tazobactam. 相似文献
8.
Jean-Luc Meyer Francis Durand René Ricou Charles Vives 《Metallurgical and Materials Transactions B》1984,15(3):471-478
Hydrodynamic and thermal fields were studied in liquid aluminum circulating in a specially built parallelepipedic ingot mold.
Fluid flow could be produced either by using an electromagnetic linear motor or by natural convection effects. Velocity measurements
were performed using a magnetodynamic probe during steady state flow experiments. A theoretical model of heat transfer and
fluid flow was developed and used to solve simultaneously Navier-Stokes and energy balance equations. The comparison of theoretical
and experimental results is satisfactory regarding general distribution of velocity and temperature. It gives a better understanding
of the effects of fluid flow in the melt produced either by external stirring or by natural convection. 相似文献
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10.
Experiments performed in a four-tenth scale physical model of a 1300 kW inductor unit are described. The approach was, first,
to measure the electromagnetic parameters, namely, the magnetic field and current density components, as well as the phase
shift between these periodic vectors; and next, to find the electromagnetic force field from these parts. These results were
connected with the experimentally determined liquid-metal flow fields. Both the effects of the time-smoothed electromagnetic
forces on solid inclusions in suspension within the melt and the influence of the fluctuating electromagnetic forces on the
probable existence of a cavitation phenomenon were also estimated. This present work, which reveals the impact of the magnetic
field leaks on the velocity pattern, may be considered as a preliminary investigation, in an attempt to control the magnetoydrodynamic
flows in channel-induction furnaces. 相似文献