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排序方式: 共有6273条查询结果,搜索用时 15 毫秒
61.
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ML Calladine 《Canadian Metallurgical Quarterly》1996,13(1):51-57
Laparoscopic ultrasound combines the advantage of diagnostic laparoscopy with intraoperative ultrasonography. This new technique allows visualisation of deep structures that are not palpable. The technical aspects and the application in abdominal surgery are described. The principal indications are detection of common bile duct stones during laparoscopic cholecystectomy and staging of abdominal cancers. The information provided by laparoscopic ultrasound influences therapeutic decisions. 相似文献
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MJ van den Brand A van Miltenburg MJ de Boer LR van der Wieken PJ de Feyter ML Simoons 《Canadian Metallurgical Quarterly》1994,10(3):177-185
Patients with unstable angina, refractory to intensive medical therapy, are at high risk for developing thrombotic complications, such as recurrent ischemia, myocardial infarction and coronary occlusion during coronary angioplasty. As both platelet aggregation and/or thrombus formation play an important role in this ongoing ischemic process, a monoclonal platelet GPIIb/IIIa receptor antibody (c7E3) or thrombolytic therapy (alteplase) might be able to modify the clinical course and underlying coronary lesion morphology. To evaluate whether alteplase or c7E3 could influence the incidence of complications, we randomized 36 and 60 patients, respectively to alteplase or placebo, or c7E3 or placebo. All patients exhibited dynamic ECG changes and recurrent pain attacks, despite maximal tolerated medical therapy. Patients were randomized in both studies after initial angiography had demonstrated a culprit lesion amenable for angioplasty. After study drug infusion quantitative angiography was repeated and angioplasty performed. Recurrent ischemia during study drug infusion occurred in 5, 6, 9 and 16 patients from the alteplase, placebo, c7E3 and placebo group, respectively. Major events defined as death, myocardial infarction or urgent intervention occurred in 7, 3, 1 and 7 patients, respectively. Two patients died: one in the alteplase group and one in the placebo group from the c7E3 study. The first patient due to retroperitoneal hemorrhage, the second as a result of recurrent infarction. Qualitative angiography showed resolution of clots in the c7E3 group only, while the same group of patients showed in 20% an improvement in TIMI flow grade, without deterioration in any patient from this group.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
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A previous pilot study demonstrated that a force and frequency-weighted filter network could be developed for processing continuous biomechanical measures of repetitive wrist motions and exertions. The current study achieves the objective by modelling subjective discomfort for repetitive wrist flexion using controlled posture, pace and force. A three-level fractional factorial experiment was conducted involving repetitive wrist flexion (2 s/motion, 6 s/motion, 10 s/motion) from a neutral posture to a given angle (10 degrees, 28 degrees, 45 degrees) against a controlled resistance (5 N, 25 N, 50 N) using a Box Behnken design. Ten subjects participated. Discomfort was reported on a 10 cm visual analogue scale. Results of response surface regression analysis revealed that main effects of force, wrist flexion angle, and repetition were all significant (p < 0.05) and that no second-order effects were observed. Linear regression analysis on these factors established a discomfort model on which the filter characteristics were based. The pure error test model revealed no significant lack of fit (p > 0.05). The continuous model was compared and agreed with discrete psychophysical data from other published studies. The model was used for generating parameters for a force and frequency-weighted digital filter that weighs continuous wrist postural signals with corresponding force in proportion to the equal discomfort function as a function of frequency of repetition. These filters will enable integration of large quantities of biomechanical data in field studies. 相似文献
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Although the good appearance and biocompatibility of dental porcelains, failures are still of considerable concern because of the limited properties to all ceramic system. Physical properties that might be considered ideal include high strength, resistance to abrasion, and resistance to the hostile oral environment. Porcelain has been considered by many of its physical characteristic are similar to those of enamel. In 1983 a new modality of treatment, the etched porcelain restoration was introduced by Simonsen and Calamia. Numerous investigations have shown the strength of the etched porcelain bonded to composite resin and also the clinical success of this porcelain to be used as laminated veneers and etched inlays and onlays. 相似文献
69.
P. J. Castro J. J. Barroso R. A. Correa 《Journal of Infrared, Millimeter and Terahertz Waves》1993,14(2):383-395
A study of selective properties of coaxial open cylindrical resonators have been conducted experimentally and compared with theory. The resonator consists of an inner circular cylinder symmetrically located inside an outer weakly irregular open waveguide. Several fundamental TE modes were identified over the range 9 to 17 GHz through measurements of the resonant frequencies and the associated loaded quality factors. It has been verified that the structure and the number of resonant modes are both strongly dependent on the diameter of the coaxial insert. Such an electrodynamical system proves to be useful in guided wave applications requiring, for example, filters, frequency-tunable resonators and devices for analyzing the modal composition of a signal. 相似文献
70.
WA Schumacher CL Heran TE Steinbacher S Youssef ML Ogletree 《Canadian Metallurgical Quarterly》1993,22(4):526-533
We determined the effects of aspirin and a novel thromboxane A2/prostaglandin endoperoxide (TP)-receptor antagonist, BMS-180291, on thrombosis and bleeding times in skin and mesenteric arteries. In anesthetized rats, occlusive thrombosis was induced in the carotid artery by topical application of ferrous chloride and in the vena cava by blood flow stasis combined with either infusion of thromboplastin or hypotonic saline. Aspirin (1, 10, and 50 mg/kg) did not reduce arterial or venous thrombus weight significantly. BMS 180,291 (150 micrograms/kg/min) decreased arterial thrombus weight and hypotonic saline-induced caval thrombus weight by 58 and 57%, respectively. BMS-180291 lacked antithrombotic activity at a lower dose (50 micrograms/kg/min) and failed to inhibit thromboplastin-induced caval thrombosis. BMS-180291 (150 micrograms/kg/min) significantly reduced arterial thrombus weight by 40% when plasma epinephrine concentration was increased to 5 ng/ml. BMS-180291 and aspirin produced increases of only < or = 30% in bleeding times. These results demonstrate that BMS-180291 has antithrombotic activity in experimental aspirin-resistant arterial and venous thrombosis. Both aspirin and BMS-180291 have only modest effects on small artery hemostasis in rats. 相似文献