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1.
For the past 10 to 15 years, radiation therapy and chemotherapy have played an increasingly important role in the treatment of various gastrointestinal malignancies, most prominently in anal and rectal cancer. Critical issues in the care of patients with anal and rectal cancer include not only local control and survival but organ preservation as well. For patients with carcinoma of the anal canal, external-beam irradiation with 5-fluorouracil and chemotherapy with mitomycin C have replaced surgery as primary therapy. Current studies are optimizing this therapy. In contrast, the management of distal rectal cancer is in evolution. Although the abdominoperineal resection has been long regarded as the definitive treatment of distal rectal cancer, it is associated with substantial morbidity (loss of anorectal function with a permanent colostomy and a high incidence of sexual and genitourinary dysfunction). As an alternative, treatment programs utilizing sphincter-preserving procedures with radiation therapy and chemotherapy are under active investigation. In selected patients, these strategies appear promising, and there have been reports of satisfactory local control and survival, as well as preservation of sphincter integrity.  相似文献   
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平板液晶技术的迅猛发展让大屏幕、宽视角、高质量的视频图像得以实现。但是,随着液晶电视的屏幕变大、亮度更高,工作时所需的电压和电流也逐渐增加。而且,由于液晶电视屏幕中配置了多种供用户使用的接口,所以特别容易由于过电流和过电压的原因而出现损坏。  相似文献   
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In a 63-year-old woman with longstanding type I diabetes mellitus, CAD and chronic heart failure, a subacute myocardial infarction developed, together with decompensation of cardiac function and diabetes and concurrent pneumonia. Acute heart failure with acute renal failure on top of diabetic nephropathy, and interstitial pulmonary edema was initially treated with hemofiltration and catechol amines together with antibiotic and perfusor-regulated insulin therapy, and systemic heparinization. Subsequent chronic treatment with digitalis, acetyl salicylic acid, insulin and a combination of an ACE inhibitor and a loop diuretic resulted in an improvement of heart failure to NYHA functional class II where PTCA of coronary multi-vessel disease could be performed with low risk.  相似文献   
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The influence of extra-cellular polymeric substances in microbiologically influenced corrosion Unexpected pitting failures in copper potable water installations have occurred in some countries (Germany, Sweden, Scotland, South-West England, Saudi-Arabia) in the mid-eighties. These failures could not be expected in a single case based on the chemical composition of the potable water. Further typical manifestation characteristics of this microbiologically influenced corrosion have been i.) an uptake of dissolved and undissolved copper species in an obsolete, non regular fashion, ii.) black layers of copper(II)-oxide on the inner tube surface, accompanied by posniakite and malachite in the pitting areas, and, iii.) the detection of extracellular polymeric substances (EPS). These EPS consist partly of polysaccharides. They could either be produced by microorganisms within the potable water installation or be transported in a dissolved or undissolved state into the installation. Consequently, they sediment on the inner surfaces of the copper tubes. The physico-chemical properties of some kinds of EPS, especially their membrane properties and their cation selectivity, play a key role in this corrosion process. This is shown exemplarily performing diffusion potential measurements and contact corrosion experiments.  相似文献   
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Abstract Teaching with the world-wide web is becoming a common practice in modern education. The web serves two main interrelated functions, namely, retrieval and publication of information. To enhance learning and motivation, the student-as-teacher (SAT) principle was adopted in the study reported in this paper. Students were given the role of teacher of high school students and the general public about the subject matter they learned on a course. To achieve this goal, the students created educational web sites featuring two selected psychological professions. Being the major assignment for the course, the web sites created by students received higher scores than the assignments of their peers who learned the same materials through traditional pedagogical approaches. Course evaluation confirmed that the web implementation of the SAT principle enhanced learning, increased motivation and provided a transfer-able skill, without compromising accomplishment of major course goals.  相似文献   
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Infective endocarditis in heroin addicts has been reported to have a mortality as high as 85% and reports have varied widely regarding predominant valvular involvement and infecting microorganisms. A retrspective study was done and 61 cases of heroin-associated infective endocarditis were identified at Freedmen's Hospital and the District of Columbia General Hospital, Washington, DC between January 1969 and January 1973. Our results indicate that staphylococcal infection of the tricuspid valve has a much higher incidence in this population than has generally been believed and that it is the predominant presentation of infective endocarditis in these patients. The outcome of patients in our series compares favorably with previous reports and suggests that early diagnosis and prompt institution of appropriate antimicrobial therapy are important and may lead to improved survival in addicts with tricuspid endocarditis.  相似文献   
10.
The posterior wall of the central sulcus in forelimb area of SI has been expolred with extracellular micro-electrodes in baboons lightyl anaesthetized with nitrous oxide and sodium thiopentone. 2. The excitatory responses of 130 single units to low intensity electrical stimulation of the deep radial (muscle) and the superficial radial (cutaneous) nerves have been investigated. 3. Units that responded only to muscle nerve stimulation were located in area 3a but overlapped into area 3b. Units that responded only to cutaneous nerve stimulation were found mainly in area 3b but a number occurred in area 3a. Units that responded to both muscle and nerve stimuli (convergent units) were found throughout area 3a and the rostral part of area 3b. 4. Latency analyses of all three response groups revealed a single population of units responding to low threshold muscle nerve stimulation (mean latency 8.5 msec), and both early and late populations responding to low threshold cutaneous nerve stimulation (mean latencies 9.5 and 13.6 msec respectively). A number of the convergent units had very similar latencies for both inputs. 5. Electrical stimulation within area 3a deminstrated a projection from areas 1 and 3b to area 3a; such a pathway may provide a route for excitation of the late skin population which was found mainly in area 3a. 6. In area 3a units commonly responded to light touch, local pressure or deep pressure but only rarely to movement of hairs. A number of the convergent units responded to natural stimulation of cutaneous receptors.  相似文献   
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