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PURPOSE: To compare the outcomes of hemodialysis catheters placed by interventional radiologists with those placed by surgeons. MATERIALS AND METHODS: The outcomes were retrospectively analyzed of 237 hemodialysis catheters placed in 140 patients by a radiology service from January 1991 through December 1992. Follow-up data were available for 222 catheters (94%). Catheter secondary patency and freedom from infection were analyzed statistically and by means of life-table analysis. RESULTS: Pneumothorax occurred after the placement of six catheters (2.5%); in two patients, a chest tube was required for decompression. Other short-term complications included air embolism with no clinical sequelae (two procedures) and prolonged oozing from the tunnel (two procedures). Long-term complications included infection and catheter failure. Infection occurred in 26 patients (18%) with 32 catheters (14%) and resulted in removal of 25 catheters. Ninety-three catheters (42%) failed, and 63 catheters (28%) were removed because of failure. CONCLUSION: Hemodialysis catheters placed by radiologists do not have a higher rate of complications or failure than catheters placed by surgeons.  相似文献   

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Three field investigations were carried out to assess the feasibility of raising salmonella-free finishers from pigs born in infected herds, by moving the pigs to clean and disinfected facilities before their expected exposure to the bacteria from the environment. Three herds with persistently high levels of subclinical infection with S typhimurium in the finishing pigs were used. They practised all-in all-out management in the nurseries and in the grower units. A total of 844 pigs were moved, either at weaning, from the nursery, or from the grower unit to newly built or rigorously cleaned and disinfected finishing units with no known history of salmonella infection. No detectable infection was observed at slaughter either serologically or bacteriologically by random testing of the pigs which had been moved, whereas a proportion of the pigs raised at the same time in the continuous systems on the farms were found to be infected.  相似文献   

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Pefloxacin, ciprofloxacin and norfloxacin were shown to induce elimination of the virulence plasmids in the strains of Y. pseudotuberculosis. Pefloxacin had a more pronounced eliminating effect than ciprofloxacin and norfloxacin. The elimination of the virulence plasmids with the molecular weight of 40-50 MD in the strains of Y. pseudotuberculosis was more frequent at the subinhibitory concentrations of the fluoroquinolones or at 1/4 of the fluoroquinolone MIC., At 1/8 of the MIC it was rarer. The virulence plasmid elimination in the strains was observed in spite of their serovar but was more frequent in the serovar 1B strains.  相似文献   

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Hemodialysis access failure is a major cause of morbidity for patients with end stage renal disease with costs in excess of $743 million annually. Color-flow doppler ultrasound is the only mobile noninvasive technique that provides direct visual imaging of the access and measurement of access flow. Doppler ultrasound can identify patients at increased risk of future thrombosis and allow preventive intervention. Prospective trials show that ultrasound-based access management programs can decrease thrombosis rates, prolong access longevity, and decrease the cost of hemodialysis access management. It should be included as part of a coordinated program of hemodialysis management.  相似文献   

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As shown by Koistinen,1,2 rapid induction heating and quenching can be used to eliminate the yield point and stretcher strains that appear during forming operations on low-carbon steel sheets. Here it is pointed out that such rapid temperature change can produce inhomogeneous plastic deformation, and is then the thermal equivalent of temper rolling or flex-leveling. Theoretical heating (cooling) requirements for eliminating discontinuous yielding on this basis are derived from existing thermoelastic solutions, and experimental results on aged temper-rolled sheet specimens are presented in support of the calculations. The necessary rate of temperature change is more easily reached by quenching than by rapid heating, but rapid heating is essential to control the carbon and nitrogen taken into solution and for high product output. The required rate of temperature change is easily obtainable for sheets of 14 gage (0.19 cm) and heavier, but as sheets become thinner the minimum rate increases rapidly. Because of an increased rate of aging after rapid heating and cooling, the process is of little interest to steel producers as a substitute for temper rolling, but may be attractive to industries which consume large quantities of rimmed steel sheet.  相似文献   

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浅析焊接残余应力及其消除方法   总被引:3,自引:0,他引:3  
简介了焊接残余应力危害的特点,影响因素、测量及消除残余应力的几种方法,重点论述爆炸法消除焊接残余应力的有关问题。  相似文献   

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用硅代替铝脱氧来消除连铸水口堵塞   总被引:1,自引:0,他引:1  
卢盛意 《炼钢》2004,20(6):32-36
一些Al镇静钢在优化钢包渣成分和控制FeSi中Al和Ca含量的条件下有被Si镇静钢取代的趋势。Si镇静钢的优点是可以消除水口堵塞.钢的纯净度与Al镇静钢相近。  相似文献   

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The efficacy of five daily treatments with 7.5 mg fenbendazole/kg bodyweight against mucosal cyathostome larvae was evaluated in 20 12- and 24-month-old ponies with naturally acquired cyathostome infections. After three weeks communal grazing on infected pasture and six weeks indoors, one group of 10 ponies were treated. Six weeks later, both groups of ponies were humanely destroyed and their burdens of large intestinal cyathostome worms, including luminal parasites and mucosal larvae, were assessed. In the control animals approximately 7 per cent of the total worm burden was present in the gut lumen and 93 per cent was present as larvae in the large intestinal mucosa. The efficacy of fenbendazole against the luminal cyathostomes was 90.7 per cent (P < 0.01). The total numbers of mucosal larvae, recovered after digestion, were reduced by 95.3 per cent (P < 0.0005); mucosal late third and fourth stage larvae were reduced by 99.4 per cent (P < 0.0001), and early inhibited third stage larvae by 91.5 per cent (P < 0.005).  相似文献   

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Arylamidase activity in human endometrium tissue, uterine fluid, and serum in uterine dysfunction induced by a copper IUD, steroidal contraception, and lactational amenorrhea was investigated. Arylamidase activity in cell-free preparation of endometrium increased steadily from the early proliferative phase attaining the maximum level at the secretory phase. The activity in the uterine fluid and serum showed similar trends. In uterine dysfunction, the activity decreased in different conditions. The distribution of the enzyme activity in the particular and soluble fractions was within a close range (1.4 to 1.7), indicating the absence of transfer of enzyme from particulate to the soluble fraction. The administration (in vitro) of 10 -4 M estrogen and progesterone caused an increase in the activity. Substrate affinity values of the enzymes in both fractions remained unaffected while the catalytic phase values were altered indicating a qualitative difference in the 2 enzymes.  相似文献   

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对73×5.51油管表面结疤、性能不稳定等问题进行了分析、研究,提出了控温轧制的最佳工艺方案,从而减少直至根除了终轧温度对性能的不良影响。  相似文献   

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Here, we describe a novel strategy called enzymatic "Mop-Up" that efficiently removes contaminating dNTPs from reverse-phase, high-performance liquid chromatography (RP-HPLC) purified 3'-O-modified dNTP syntheses. Enzymatic mop-up takes advantage of the high selectivity of DNA polymerases for the former nucleoside triphosphates over the latter nucleotide analogs. We demonstrate the selective removal of contaminating dATP and dTTP from RP-HPLC purified 3'-O-methyl-dATP and 3'-O-(2-nitrobenzyl)-dTTP syntheses, respectively. These data highlight the importance of natural nucleotide contamination when interpreting enzymatic incorporation data and provide an alternative hypothesis for the observed property of catalytic editing of DNA polymerases. Moreover, the effective removal of natural nucleotides from 3'-O-modified analogs addresses the important issue of nucleotide read-through for stop-start DNA sequencing strategies, such as the base addition sequencing scheme (BASS).  相似文献   

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A liver transplant patient who developed renal failure postoperatively was treated using continuous hemodiafiltration (CHDF). Doses ranging from 0.01 to 0.06 mg/kg/day of FK-506 had been administered intravenously. FK-506 concentrations before and after the filter, and in the ultradiafiltrate were 45.3 +/- 2.9, 56.0 +/- 5.3, and 9.1 +/- 3.1 ng/ml (mean, +/- S.D.), respectively. The filtration rate was 23.6 +/- 6.4%, and extracted FK-506 amounted to 522.0 micrograms (11.3% of administered dose). A part of the FK-506 administered was eliminated through the filter during CHDF.  相似文献   

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Polyvinyl chloride, of all the plastic polymers, has been implicated primarily in causing the most serious problem in fire fighting today because it releases hydrogen chloride gas when burning. One hundred seventy fire fighters who experienced symptoms from its toxicity have been studied from 1970 to 1975. One died.  相似文献   

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在CAS-OB工艺中,下罩前底吹排渣面积直接影响钢水处理的可靠性,作采用水力学模型实验对300t钢包底吹排渣效果进行了研究,主要考察了底吹气体流量和顶渣层厚度对排渣效果的影响,同时测试了底吹位置对排渣直径的影响程度,结果表明:底吹气体流量和渣量对排渣效果有显影响。  相似文献   

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A methodology of how to exploit the Niyama criterion for the elimination of various defects such as centerline porosity, macrosegregation, and hot tearing in steel castings is presented. The tendency of forming centerline porosity is governed by the temperature distribution close to the end of the solidification interval, specifically by thermal gradients and cooling rates. The physics behind macrosegregation and hot tears indicate that these two defects also are dependent heavily on thermal gradients and pressure drop in the mushy zone. The objective of this work is to show that by optimizing the solidification pattern, i.e., establishing directional and progressive solidification with the help of the Niyama criterion, macrosegregation and hot tearing issues can be both minimized or eliminated entirely. An original casting layout was simulated using a transient three-dimensional (3-D) thermal fluid model incorporated in a commercial simulation software package to determine potential flaws and inadequacies. Based on the initial casting process assessment, multiobjective optimization of the solidification pattern of the considered steel part followed. That is, the multiobjective optimization problem of choosing the proper riser and chill designs has been investigated using genetic algorithms while simultaneously considering their impact on centerline porosity, the macrosegregation pattern, and primarily on hot tear formation.  相似文献   

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CONTEXT: Although blacks receive lower doses of hemodialysis than whites, their survival when receiving dialysis treatment is better than that for whites. Previous studies of the relationship between the dose of dialysis and patient survival have not controlled for differences in patient characteristics. OBJECTIVE: To examine the association of mortality with the dose of hemodialysis for clusters of patients categorized by race and sex. DESIGN: Retrospective analysis of laboratory data and mortality outcomes from 1994, using a national database of hemodialysis patients. PATIENTS: A total of 18144 black and white patients receiving hemodialysis 3 times weekly who either lived the entire year receiving hemodialysis or died. MAIN OUTCOME MEASURES: The fractional reduction of urea in a single dialysis session as the measured hemodialysis dose (urea reduction ratio [URR]) after controlling for race, sex, age, and diabetes mellitus. Mortality was determined by strata of URRs and albumin and creatinine levels. RESULTS: Across all age categories, blacks had lower URRs than whites, and men had lower URRs than women. In an age-adjusted model for evaluating interactions among URRs, race, sex, and diabetes, the association of URR with mortality risk was weak among blacks, particularly black men. After adjustment for age and diabetes, death probability curves were most steep for white women with URR values less than 60%. The death probability curves were least steep for black men. There was no meaningful difference between death probability and albumin or creatinine concentration among the race by sex clusters. CONCLUSION: Using URR, the usual measure of hemodialysis dose, the assumption that the association between dialysis dose and survival is uniform across demographic groups appears incorrect. Comparisons of the quality of dialysis patient care should not rely on URR alone to predict patient survival.  相似文献   

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