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排序方式: 共有873条查询结果,搜索用时 15 毫秒
31.
A Kassam JW Overstreet C Snow-Harter MJ De Souza EB Gold BL Lasley 《Canadian Metallurgical Quarterly》1996,104(4):408-413
The sensitivity and specificity of a urinary pregnanediol-3-glucuronide (PdG) ratio algorithm to identify anovulatory cycles was studied prospectively in two independent populations of women. Urinary hormone data from the first group was used to develop the algorithm, and data from the second group was used for its validation. PdG ratios were calculated by a cycles method in which daily PdG concentrations indexed by creatinine (CR) from cycle day 11 onward were divided by a baseline PdG (average PdG/Cr concentration for cycle days 6-10). In the interval method, daily PdG/CR concentrations from day 1 onward were divided by baseline PdG (lowest 5-day average of PdG/CR values throughout the collection period). Evaluation of the first study population (n = 6) resulted in cycles with PdG ratios > or = 3 for > or = 3 consecutive days being classified as ovulatory; otherwise they were anovulatory. The sensitivity and specificity of the PdG ratio algorithm to identify anovulatory cycles in the second population were 75% and 89.5%, respectively, for all cycles (n = 88); 50% and 88.3% for first cycles (n = 40) using the cycles method; 75% and 92.2%, respectively, for all cycles (n = 89); and 50% and 94.1% for first cycles (n = 40) using the interval method. The "gold standard" for anovulation was weekly serum samples < or = 2 ng/ml progesterone. The sensitivity values for all cycles and for the first cycle using both methods were underestimated because of apparent misclassification of cycles using serum progesterone due to infrequent blood collection. Blood collection more than once a week would have greatly improved the sensitivity and modestly improved the specificity of the algorithm. The PdG ratio algorithm provides an efficient approach for screening urine samples collected in epidemiologic studies of reproductive health in women. 相似文献
32.
EB Podgorsak L Souhami JL Caron M Pla B Clark C Pla P Cadman 《Canadian Metallurgical Quarterly》1993,27(5):1225-1230
PURPOSE: The excellent treatment results obtained with traditional radiosurgery have stimulated attempts to broaden the range of intracranial disorders treated with radiosurgical techniques. For major users of radiosurgery this resulted in a gradual shift from treating vascular diseases in a single session to treating small, well delineated primary tumors on a fractionated basis. In this paper we present the technique currently used in Montreal for the fractionated stereotactic radiotherapy of selected intracranial lesions. METHODS AND MATERIALS: The regimen of six fractions given every other day has been in use for "fractionated stereotactic radiotherapy" in our center for the past 5 years. Our current irradiation technique, however, evolved from our initial method of using the stereotactic frame for target localization and first treatment, and a "halo-ring" with tattoo skin marks for the subsequent treatments. Recently, we developed a more precise irradiation technique, based on an in-house-built stereotactic frame which is left attached to the patient's skull for the duration of the fractionated regimen. Patients are treated with the stereotactic dynamic rotation technique on a 10 MV linear accelerator (linac). RESULTS: In preparation for the first treatment, the stereotactic frame is attached to the patient's skull and the coordinates of the target center are determined. The dose distribution is then calculated, the target coordinates are marked onto a Lucite target localization box, and the patient is placed into the treatment position on the linac with the help of laser positioning devices. The Lucite target localization box is then removed, the target information is tattooed on the patient's skin, and the patient is given the first treatment. The tattoo marks in conjunction with the target information on the Lucite target localization box are used for patient set-up on the linac for the subsequent 5 treatments. The location of the target center is marked with radio-opaque markers on the target localization box and verified with a computerized tomography scanner prior to the second treatment. The same verification is done prior to other treatments when the target center indicated by the target localization box disagrees with that indicated by the tattoo marks. The new position of the target center is then determined and used for treatment positioning. CONCLUSION: The in-house-built frame is inexpensive and easily left attached to the patient's skull for the 12 day duration of the fractionated regimen. Positioning with the Lucite target localization box verified with tattoo marks ensures a high level of precision for individual fractionated treatments. 相似文献
33.
GM Roshchina EB Lishnevskaia IA Sizova VA Orlova IM Tereshin 《Canadian Metallurgical Quarterly》1980,25(11):850-854
The technique of accumulating preparation of the mucosa and "turned out sac" was used to show that levorin, a polyenic antibiotic in a concentration of 10(-6) M, lowered the transport rate and accumulation of glucose by the epithelial cells of the rat thin intestine under conditions of oxygenation. Suppression of the glucose transport in the first stages resulted in partial inhibition of the transmembrane transfer. It is suggested that levorin suppression of the glucose transport through the erythrocyte apical membrane in the thin intestine is associated with a decrease in the electrochemical gradient of Na+. 相似文献
34.
Fifteen fresh cadaver impacts were conducted in simulation of pedestrian-automobile accidents. The test sled configuration simulated an automobile bumper and hood in "standard" and "nosedive" situations as well as "hard" and "soft" impact surfaces. Instrumentation and film demonstrated large axial compression forces in the struck leg and considerable angular velocity of the torso in all modes. Dissection revealed primary injury at the impact site at low velocities with added remote injury at high velocities. Fracture of the lateral tibial plateau was most common. Lowering the bumper height offered the greatest protection against injury at moderate impact velocities. 相似文献
35.
Cardiac transplantation in perspective for the future. Survival, complications, rehabilitation, and cost 总被引:1,自引:0,他引:1
JL Pennock PE Oyer BA Reitz SW Jamieson CP Bieber J Wallwork EB Stinson NE Shumway 《Canadian Metallurgical Quarterly》1982,83(2):168-177
Two hundred twenty-seven cardiac transplant procedures have been performed in 206 patients from January, 1968, to April, 1981. Postoperative survival rates, calculated by the actuarial method for program years 1968 to 1973 (66 patients), are 44%, 33%, 27%, 21%, and 18% at 1, 2, 3, 4, and 5 years after transplantation, respectively. Postoperative survival rates for program years 1974 to 1981 (140 patients) are 63%, 55%, 51, 44%, and 39% at 1, 2, 3, 4, and 5 years after transplantation, respectively. This increase results primarily from improvement in survival achieved in the first 3 postoperative months (59% +/- 7%, 1968 to 1973, versus 80% +/- 40%, 1974 to 1980), reflecting improved patient management. Infection remains the primary cause of death following transplantation (76/131 patients, 58%), followed by acute rejection (24/181, 18.3%), graft arteriosclerosis (14/131, 10.7%), and malignancy (6/131, 4.6%). The development of graft arteriosclerosis has been examined in 85 one-year survivors studied by annual coronary arteriograms. Coronary lesions of varying severity have developed in 21 patients. HLA-A2 incompatibility was associated with a higher incidence of graft arteriosclerosis than was apparent for all other A locus incompatibilities (p less than 0.0003). Lymphoma has been shown to be associated with younger recipient age, a primary disease diagnosis of idiopathic cardiomyopathy, and retransplantation. One hundred six patients have survived at least 1 year after transplantation; 97% were in NYHA Class 1 at that time interval and 82% returned to employment or activity of choice. The longest survival time is new 11 years, 3 months. Cardiac transplantation can be considered "reasonable and therapeutic treatment to extend life" in selected individuals. 相似文献
36.
37.
Interpolyelectrolyte complexes of maleic acid copolymers and chitosan for stabilization and functionalization of magnetite nano‐ and microparticles 下载免费PDF全文
A facile method of preparation of stabilized and functionalized nano‐ and microparticles of magnetite by successive application of oppositely charged polymers with a regular structure of macromolecular chains (chitosan and maleic acid copolymers) onto Fe3O4 core are developed. This approach makes it possible to create two types of magnetite interpolyelectrolyte shells, containing carboxylic or amino groups in outer layer of shell. Composition and magnetic properties of composite particles depend on nature of the copolymer of maleic acid, reaction conditions and size of obtained particles. The carboxylic groups of copolymer in outer layer of interpolyelectrolyte shell were converted into reactive anhydride groups by heating. Thermal treatment also leads to covalent crosslinking of shell and improves stability of composites both in acidic and alkaline media. Horseradish peroxidase was successfully immobilized onto covalently crosslinked and activated microparticles of Fe3O4 in aqueous medium without of condensing agents. The proposed reproducible and low‐cost technique does not use toxic reagents or solvents at all stages, including preparation of Fe3O4, formation, activation and crosslinking, of magnetite shell, modification of activated surface of composite particles. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39663. 相似文献
38.
K Torrungruang H Feister D Swartz EB Hancock J Hock JP Bidwell 《Canadian Metallurgical Quarterly》1998,22(4):317-324
This study assessed the prevalence of tobacco and alcohol use in top-grossing American films from 1985 to 1995. The top ten money-making films for 1985 to 1995 were viewed to identify the prevalence of alcohol and tobacco use overall and by lead characters. While the use of tobacco and alcohol was stable across the study period, use of these substances was common. Most films (98%) had references that supported tobacco use and 96% had references that supported alcohol use. Discouraging the use of these substances was uncommon. Only one third of films had any references that discouraged the use of tobacco or alcohol (38% and 37%, respectively). At least one lead character used tobacco or alcohol in 46% and 79% of the films, respectively. The hazards of smoking and drinking are not reflected in the behaviors of film characters who are potential role models for youth facing the decision to smoke or drink. 相似文献
39.
H Kagaya M Sharma R Kobetic EB Marsolais 《Canadian Metallurgical Quarterly》1998,77(1):49-54; quiz 65-6
Joint contractures have been one of the contraindications for use of functional electrical stimulation for standing in paraplegic patients. A simulation study using a three-segment link mechanical model of the human body was performed to calculate the muscle moments at the ankles, knees, and hips during standing with and without having joint contractures. The knee and hip angles were varied in 5 degrees increments, whereas the ankle angles were varied in 1 degree increments. It was assumed that energy efficient posture was obtained with the least sum of the squared moments of the ankles, knees, and hips joints by the muscles. Ankles at 5 degrees of dorsiflexion, knees at 0 degrees, and hips at 15 degrees of extension resulted in the most energy efficient posture without joint contractures. The muscle moments increased with the increase in angle of contractures. The joint contractures at ankle angles > or = 6 degrees of plantar flexion, knee angles > or = 20 degrees of flexion, and/or hip angles > or = 20 degrees of flexion produce a potentially unstable posture. These findings suggest that some degree of joint contractures can be tolerated in paraplegic patients using functional electrical stimulation for standing. 相似文献
40.
J Nikolakopoulos C Zachariah D Mota de Freitas EB Stubbs R Ramasamy MC Castro CF Geraldes 《Canadian Metallurgical Quarterly》1998,71(4):1676-1684
Lithium has been used clinically in the treatment of manic depression. However, its pharmacologic mode of action remains unclear. Characteristics of Li+ interactions in red blood cells (RBCs) have been identified. We investigated Li+ interactions on human neuroblastoma SH-SY5Y cells by developing a novel 7Li NMR method that provided a clear estimation of the intra- and extracellular amounts of Li+ in the presence of the shift reagent thulium-1,4,7,10-tetrazacyclododecane-N,N',N',N'-tetramethylene phosphonate (HTmDOTP4-). The first-order rate constants of Li+ influx and efflux for perfused, agarose-embedded SH-SY5Y cells in the presence of 3 mM HTmDOTP4- were 0.055 +/- 0.006 (n = 4) and -0.025 +/- 0.006 min(-1) (n = 3), respectively. Significant increases in the rate constants of Li+ influx and efflux in the presence of 0.05 mM veratridine indicated the presence of Na+ channel-mediated Li+ transport in SH-SY5Y cells. 7Li NMR relaxation measurements showed that Li+ is immobilized more in human neuroblastoma SH-SY5Y cells than in human RBCs. 相似文献