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991.
The influence of heat transfer processes in arc discharges on the development of thermal instability is considered. A substantial dependence of the process of destabilization on the plasma properties is shown by the example of argon and helium arcs. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 70, No. 1, pp. 93–98, January–February, 1997.  相似文献   
992.
Results from this laboratory have shown that bone metabolism is directly related to extracellular pH and that high concentrations of tobramycin released from impregnated polymethylmethacryrate (PMMA) beads has pH-dependent toxic effects on bone. In the present study, beneficial effects of calcium hydroxide-impregnated PMMA were investigated regarding tobramycin toxicity and bone metabolism in chick embryo tibiae in vitro. Also using Ca(OH)2 as a pH regulator, the antibiotic efficacy of tobramycin-impregnated PMMA was evaluated with respect to inhibition of Staphylococcus aureus growth. When Ca(OH)2 was added to PMMA beads containing tobramycin, the beads released hydroxyl and calcium ions into the culture medium and released more antibiotic than beads containing only tobramycin. Bone metabolism (glycolysis, total protein synthesis, and collagen synthesis) was enhanced by Ca(OH)2-impregnated beads with or without tobramycin. Additionally, bacterial growth was inhibited more strongly when S. aureus was incubated with tobramycin- and Ca(OH)2-impregnated PMMA disks than with disks containing only tobramycin. This study demonstrates the feasibility of adding Ca(OH)2 to tobramycin-impregnated PMMA beads as a regulator of local pH and a promoter of bone metabolism for protection of bone when high concentrations of tobramycin are used to treat osteomyelitis. It also suggests that lower concentrations of antibiotic may be effective if Ca(OH)2 and tobramycin are administered simultaneously.  相似文献   
993.
994.
BACKGROUND: The transmission of hepatitis A virus (HAV) has been associated with the use of a number of solvent/detergent-treated factor VIII concentrates and possibly a factor IX concentrate. These reports have emphasized the necessity of using virus-inactivation methods for plasma products that are capable of inactivating nonenveloped viruses such as HAV. STUDY DESIGN AND METHODS: A simple, highly accurate titration procedure for HAV, which allows extensive kinetic investigations of virus-inactivation procedures, has been developed. This system has now been used to evaluate the efficacy of vapor heating in inactivating HAV after the addition of the virus to a range of human plasma products. RESULTS: It was demonstrated that HAV was significantly more thermostable than other picornaviruses, which reinforced the fact that such viruses cannot be used as model viruses for HAV-inactivation studies. A one-step vapor-heating procedure was demonstrated to inactivate between 5.9 and > 6.3 log10 of HAV in different products. A two-step vapor-heating procedure had the capacity to inactivate between > 8.7 and > 10.4 log10 of HAV. Both procedures were more effective in inactivating HAV than was the pasteurization procedure used for virus inactivation in human albumin solutions. CONCLUSION: These data demonstrate the efficacy of vapor heating in inactivating high-titer HAV after the spiking of plasma products with virus. This study confirms and explains the results of controlled clinical trials and long-term clinical usage with respect to the lack of HAV transmission by such vapor-heated products.  相似文献   
995.
BACKGROUND: Locally advanced thyroid cancer invading the tracheal cartilage represents a difficult treatment dilemma during thyroidectomy. METHODS: A retrospective chart review was performed to determine the results of laryngotracheal resection or tracheal cartilage shave with adjuvant radiotherapy in patients with locally advanced thyroid cancer invading the upper airway. RESULTS: Of 597 patients undergoing thyroidectomy for thyroid cancer, 40 were found to have laryngotracheal invasion. Thirty-five patients with superficial invasion underwent cartilage shave procedures with adjuvant radiotherapy; five with full-thickness invasion underwent radical resection, including tracheal sleeve resection (n = 3) or total laryngectomy (n = 2). Histologic subtypes included papillary (n = 32), follicular (n = 2), Hurthle cell (n = 1), medullary (n = 3), and anaplastic (n = 2). Of the cartilage shave group, 25 are currently alive with no evidence of disease at a mean follow-up of 81 months (range 1-290). Six developed isolated local/regional recurrence and were managed with total laryngectomy (n = 1), tracheal resection (n = 1), cervical lymphadenectomy (n = 1), or repeat radiotherapy (n = 3). All six patients remain free of disease at a mean follow-up of 5 years. Of those who underwent initial laryngotracheal resection, four remain free of disease at a mean follow-up of 5 years. The rates of 10-year disease-free survival and overall survival for all patients were 47.9% (95% confidence interval [CI] 24.8, 71.0) and 83.9% (95% CI 70.3, 97.5), respectively. CONCLUSIONS: These data suggest that adequate management of thyroid cancer with laryngotracheal invasion can be achieved with a more conservative surgical approach and adjuvant radiotherapy, reserving more radical resections for extensive primary lesions or locally recurrent disease.  相似文献   
996.
A configurable nonlinear filter generator is proposed. The nonlinear function employed is key controllable. By changing the key, a different sequence will be obtained. Simulated results show that an optimal linear complexity profile of the sequence can be generated  相似文献   
997.
Press  L. 《Computer》1993,26(12):62-67
It is shown that software export is an attainable goal for developing nations, especially when government policies are favorable, and that the industrialized nations dominating the worldwide market can expect some serious competition. Examples of the efforts of developing nations to export software to North America and Europe are cited  相似文献   
998.
BACKGROUND: Emphasis on ensuring women's access to preventive health services has increased over the past decade. Relatively little attention has been paid to whether the sex of the physician affects the rates of cancer screening among women. We examined differences between male and female physicians in the frequency of screening mammograms and Pap smears among women patients enrolled in a large Midwestern health plan. METHODS: We identified claims for mammography and Pap tests submitted by primary care physicians for 97,962 women, 18 to 75 years of age, who were enrolled in the health plan in 1990. The sex of the physician was manually coded, and the physician's age was obtained from the state licensing board. After identifying a principal physician for each woman, we calculated the frequency of mammography and Pap smears for each physician, using the number of women in his or her practice during 1990 as the denominator. Using unconditional logistic regression, we also calculated the odds ratio of having a Pap smear or mammogram for women patients with female physicians as compared with those with male physicians, controlling for the physician's and the patient's age. RESULTS: Crude rates for Pap smears and mammography were higher for the patients of female than male physicians in most age groups of physicians. The largest differences between female and male physicians were in the rates of Pap smears among the youngest physicians. For the subgroup of women enrolled in the health plan for a year who saw only one physician, after adjustment for the patient's age and the physician's age and specialty, the odds ratio for having a Pap smear was 1.99 (95 percent confidence interval, 1.72 to 2.30) for the patients of female physicians as compared with those of male physicians. For women 40 years old and older, the odds ratio for having a mammogram was 1.41 (95 percent confidence interval, 1.22 to 1.63). For both Pap smears and mammography, the differences between female and male physicians in screening rates were much more pronounced in internal medicine and family practice than in obstetrics and gynecology. CONCLUSIONS: Women are more likely to undergo screening with Pap smears and mammograms if they see female rather than male physicians, particularly if the physician is an internist or family practitioner.  相似文献   
999.
Eighty-six children who completed immunization with the two trivalent poliovirus vaccines, live attenuated (OPV) and enhanced potency inactivated (EIPV), in one of four schedules (OPV-OPV-OPV, EIPV-EIPV-EIPV, EIPV-OPV-OPV, and EIPV-EIPV-OPV) at 1 year of age were monitored serologically over the subsequent 4 years and challenged with OPV at 5 years of age. Each of the immunization groups exhibited an initial 10- to 100-fold decline in neutralizing antibody to poliovirus types 1, 2, and 3 during the first 2 years of follow-up; thereafter antibody titers stabilized. The EIPV-EIPV-OPV group maintained the highest antibody levels throughout the observation period, including the response to OPV challenge at 5 years of age. These data suggest that immunization with OPV, EIPV, and combinations of the two vaccines confers long-term immunity. Optimal systemic immunity was associated with two or more doses of EIPV.  相似文献   
1000.
Problem-prone behaviors of White American, Mexican American, and American Indian high school dropouts, students in good academic standing, and students in poor academic standing were surveyed. Generally, dropouts were most involved with drugs, perpetration of violence, and victimization by violence, students in poor standing were the next most involved, and students in good standing were least involved. Ethnicity did not interact with academic status, suggesting that differences between dropouts and students were similar across ethnic groups. Some ethnicity and gender main effects were found. Findings were related to R. Jessor's (see record 1992-23064-001) theory of problem-prone behaviors, to peer cluster theory, and to intervention design. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
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