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排序方式: 共有76条查询结果,搜索用时 109 毫秒
1.
Wojciech Zalewski Beata Niezgoda-
elasko Marek Litwin 《International Journal of Refrigeration》2000,23(7):553
In the paper the optimization of geometrical and operating parameters for evaporative fluid coolers has been presented. The algorithm of optimizational calculations contains:
- • the mathematical model of heat and mass transfer in evaporative fluid coolers;
- • model of operating costs based, among others, on the Zalewski–Gryglaszewski relations developed by the authors for evaluation of air pressure drops in the heat exchanger;
- • model of evaporative heat exchangers production costs.
2.
Serological testing for immunoglobulin G (IgG) antibodies to Helicobacter pylori has proven useful in supporting the diagnosis of infection with this organism, but the clinical value of IgA antibodies in H. pylori-related gastritis remains controversial. The purpose of our study was to determine the frequency of IgA-positive IgG-negative patients with symptoms of gastrointestinal (GI) disorders, thus assessing the clinical utility of IgA testing for H. pylori-related gastritis. It was found previously that the frequency of infected individuals in this category (IgA positive and IgG negative) is about 2%, but a large number of IgG-negative patients with GI disorders suggestive of H. pylori infection have not been investigated until now. 相似文献
3.
4.
Recovery of health related quality of life in the year after radical prostatectomy: early experience
PURPOSE: We determined the temporal course of patient return to baseline quality of life after treatment with radical prostatectomy for early stage prostate cancer. MATERIALS AND METHODS: After establishing a longitudinal observational database of men undergoing radical retropubic prostatectomy we used established, validated quality of life questionnaires (RAND 36-Item Health Survey and University of California, Los Angeles Prostate Cancer Index) to document changes in general and disease specific health related quality of life (HRQOL). We assessed 90 patients at baseline before surgery and then at 3-month intervals for 1 year postoperatively. Logistic regression was used to explore predictors of the return to baseline. RESULTS: After prostatectomy patients had a significant decrease in all domains of HRQOL. Return to baseline was rapid in the general and bowel domains with at least two-thirds to three-fourths of patients reaching pretreatment levels within 6 months of surgery. Return to baseline was slower in the urinary and sexual function domains with 61 and 31% of the men, respectively, reaching pretreatment levels by 1 year after surgery. Of those who reached baseline the average intervals for the bowel, sexual and urinary domains were 5, 6 and 7 months, respectively. Married and white patients were more likely to achieve a return to baseline HRQOL during year 1 postoperatively. However, education level was inversely associated with the likelihood of returning to baseline. CONCLUSIONS: During the year after radical prostatectomy for early stage prostate cancer patient quality of life steadily improved. By 3 months postoperatively 30 to 40% of the patients had already recovered baseline levels of physical, mental and social functioning, and by 6 months more than 70% had reached baseline in the general HRQOL domains. By 12 months after surgery 86 to 97% of the patients had returned to baseline levels in each domain. Each domain continued to improve throughout the year. For the patients who reached baseline general HRQOL during followup average recovery time was 5 to 6 months. 相似文献
5.
RT Fedderly S Berger PC Frommelt DA Lewis A Dhala AN Pelech MA Frommelt DZ Friedberg JP Thomas JS Tweddell SB Litwin 《Canadian Metallurgical Quarterly》1998,97(8):47-50
As we enter the next millennium, we are encouraged by the progress that has been made in the care of neonates, infants, and children with heart disease. Surgical repair can be offered at an earlier age with excellent results. Diseases that were uniformly fatal in the past have improved outcomes. Research continues in the area of interventional devices such that surgical repair might be eliminated or delayed. We continue to look forward to advances in the next several years that will allow for future improvement in outcome, better quality-of-life and better long-term results. 相似文献
6.
Y Khew-Goodall CM Butcher MS Litwin S Newlands EI Korpelainen LM Noack MC Berndt AF Lopez JR Gamble MA Vadas 《Canadian Metallurgical Quarterly》1996,87(4):1432-1438
P-selectin expressed on the surface of endothelium mediates leukocyte adhesion in vitro and rolling in vivo. Several inducers of cell-surface P-selectin expression on endothelial cells (EC) have previously been identified, all of which yield transient cell-surface expression of P-selectin lasting minutes to a few hours. We now show that a T-lymphocyte product, interleukin-3 (IL-3), stimulates the long-term endothelial cells (HUVEC). IL-3 induced cell-surface P-selectin expression in two phases. An initial peak at 10 minutes was followed by a prolonged upregulation beginning 16 hours after IL-3 addition and lasting at least 4 days. The level of P-selectin expression induced by IL-3 added for 48 hours was similar to that induced by treatment of HUVEC for 10 minutes with thrombin, and the effect of adding IL-3 for 48 hours followed by thrombin for 10 minutes was additive. Induction of cell-surface P-selectin expression by IL-3 was blocked by pretreatment of EC with a blocking monoclonal antibody against the IL-3 receptor alpha-chain. Lipopolysaccharide (LPS), tumor necrosis factor alpha (TNF alpha) and a mutant form of IL-3 with decreased potency did not induce cell-surface P-selectin expression after 48 hours' incubation with HUVEC, suggesting that the effect was specific to IL-3. The increase in cell-surface P-selectin expression occurring after 16 hours of incubation with IL-3 was accompanied by a similar prolonged increase in the steady-state mRNA level that was not observed at 10 minutes after IL-3 addition. As T-lymphocyte infiltration is a hallmark of chronic inflammation, our observations suggest that the secretion of IL-3 by T lymphocytes may serve to maintain the inflammatory state during chronic inflammation. 相似文献
7.
MJ Hurley C Brown E Miller DS deJongh MS Litwin 《Canadian Metallurgical Quarterly》1977,112(2):222-225
Stored human blood of varying age was passed through polyurethane foam (Bentley) micropore blood transfusion filters. Passage through these filters resulted in decreased screen filtration pressure (SFP) of the blood and increased filter weights. Numerous microaggregates were removed and SFP returned to normal after filtration. Occlusion of the filter occurred after passage of only 2 units of whole blood. On the basis of this research, we conclude that polyurethane foam (Bentley) micropore blood transfusion filters are effective in removal of microaggregates from stored human blood. Because the filtering capacity is not great, it is recommended that when these filters are used during transfusion a new filter be used for each unit of blood administered. 相似文献
8.
A new type of high voltage bipolar transistor for implementation in SOI material (Silicon-On-Insulator) has been developed. It is shown by measurements on fabricated structures and by numerical device simulations that the current drive capability of such a transistor is comparable to what has been achieved in a conventional transistor with buried layer and plug or in any optimized lateral transistor with buried emitter and collector layers. The new type of transistor designed in a few micrometer thick silicon layer has a breakdown voltage BVCEO in excess of several hundreds volts and also a remarkably high Early voltage of about 400 volts. This unique Early voltage is also explained in detail by a new analytical model. The transistor is expected to have a strong impact on the feasibility to realize mixed analog and digital signal circuits with high and low voltage functions on the same chip 相似文献
9.
Mariposa: a wide-area distributed database system 总被引:7,自引:0,他引:7
Michael Stonebraker Paul M. Aoki Witold Litwin Avi Pfeffer Adam Sah Jeff Sidell Carl Staelin Andrew Yu 《The VLDB Journal The International Journal on Very Large Data Bases》1996,5(1):48-63
The requirements of wide-area distributed database systems
differ dramatically from those of local-area network systems. In a
wide-area network
(WAN) configuration, individual sites usually report to different system
administrators, have different access and charging algorithms, install
site-specific data type extensions, and have different constraints on
servicing remote requests. Typical of the last point are production
transaction environments, which are fully engaged during normal
business hours, and cannot take on additional load. Finally, there
may be many sites participating in a WAN distributed DBMS.
In this world, a single program performing global query
optimization using a cost-based optimizer will not work well.
Cost-based optimization does not respond well to site-specific type
extension, access constraints, charging algorithms, and time-of-day
constraints. Furthermore, traditional cost-based distributed
optimizers do not scale well to a large number of possible processing
sites. Since traditional distributed DBMSs have all used cost-based
optimizers, they are not appropriate in a WAN environment, and a new
architecture is required.
We have proposed and implemented an economic paradigm as the
solution to these issues in a new distributed DBMS called Mariposa.
In this paper, we present the architecture and implementation of
Mariposa and discuss early feedback on its operating characteristics.
Edited by Henry F. Korth and Amith Sheth.
Received November 1994 / Revised June 1995
/ Accepted September 14, 1995 相似文献
10.
WF Gee HL Holtgrewe PC Albertsen MS Litwin MJ Manyak MP O'Leary MR Painter RT Blizzard RB Fenninger L Emmons 《Canadian Metallurgical Quarterly》1996,156(5):1778-1780
PURPOSE: Trends of urologist practice patterns in evaluating and treating impotence, incontinence and infertility in the United States were assessed. MATERIALS AND METHODS: In July 1995 the executive interviewing branch of the Gallup Organization selected randomly and interviewed by telephone 533 practicing urologists in the United States who had provided urological patient care for more than 20 hours per week, practiced in 1994 and completed a urological residency program. RESULTS: Treatment of male sexual dysfunction and female urinary incontinence comprises a significant portion of the professional activity of United States urologists. However, evaluation and management of male infertility occupy a small portion of the average urological work load. While more than half of United States urologist office clinical laboratories were inspected in 1994, only 2% failed evaluation due to major deficiencies. CONCLUSIONS: Male sexual dysfunction and female urinary incontinence are major areas of urological practice in the United States but male infertility is not. Few United States urologist clinical laboratories failed inspection because of major deficiencies. 相似文献