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排序方式: 共有1006条查询结果,搜索用时 15 毫秒
71.
HD Connor RG Thurman G Chen JL Poyer EG Janzen RP Mason 《Canadian Metallurgical Quarterly》1998,24(9):1364-1368
It has been proposed that the C-phenyl-N-tert-butylnitrone/trichloromethyl radical adduct (PBN/.CCl3) is metabolized to either the C-phenyl-N-tert-butylnitrone/carbon dioxide anion radical adduct (PBN/.CO2-) or the glutathione (GSH) and CCl4-dependent PBN radical adduct (PBN/[GSH-.CCl3]). Inclusion of PBN/.CCl3 in microsomal incubations containing GSH, nicotinamide adenine dinucleotide phosphate (NADPH), or GSH plus NADPH produced no electron spin resonance (ESR) spectral data indicative of the formation of either the PBN/[GSH-.CCl3] or PBN/.CO2- radical adducts. Microsomes alone or with GSH had no effect on the PBN/.CCl3 radical adduct. Addition of NADPH to a microsomal system containing PBN/.CCl3 presumably reduced the radical adduct to its ESR-silent hydroxylamine because no ESR signal was observed. The Folch extract of this system produced an ESR spectrum that was a composite of two radicals, one of which had hyperfine coupling constants identical to those of PBN/.CCl3. We conclude that PBN/.CCl3 is not metabolized into either PBN/[GSH-.CCl3] or PBN/.CO2- in microsomal systems. 相似文献
72.
The capabilities and limitations of rainbow refractometry, specifically the minimum measurable droplet size and the errors in the refractive index (temperature), have been studied. We evaluate what we believe is a new method of indirectly applying the Lorenz-Mie theory to rainbow refractometry. The results show that this new method reduces the errors and eliminates the biases that may occur if the Airy theory is used. A more precise method to filter the high-frequency oscillations associated with the measurement signals was developed. Finally, it was discovered that the errors associated with rainbow refractometry are such that a single droplet measurement is unreliable. A mean refractive index should be determined on the basis of multiple droplet measurements. 相似文献
73.
Kevin C Weng Charles O Noble Brigitte Papahadjopoulos-Sternberg Fanqing F Chen Daryl C Drummond Dmitri B Kirpotin Donghui Wang Yun K Hom Byron Hann John W Park 《Nano letters》2008,8(9):2851-2857
Targeted drug delivery systems that combine imaging and therapeutic modalities in a single macromolecular construct may offer advantages in the development and application of nanomedicines. To incorporate the unique optical properties of luminescent quantum dots (QDs) into immunoliposomes for cancer diagnosis and treatment, we describe the synthesis, biophysical characterization, tumor cell-selective internalization, and anticancer drug delivery of QD-conjugated immunoliposome-based nanoparticles (QD-ILs). Pharmacokinetic properties and in vivo imaging capability of QD-ILs were also investigated. Freeze-fracture electron microscopy was used to visualize naked QDs, liposome controls, nontargeted QD-conjugated liposomes (QD-Ls), and QD-ILs. QD-ILs prepared by insertion of anti-HER2 scFv exhibited efficient receptor-mediated endocytosis in HER2-overexpressing SK-BR-3 and MCF-7/HER2 cells but not in control MCF-7 cells as analyzed by flow cytometry and confocal microscopy. In contrast, nontargeted QD-Ls showed minimal binding and uptake in these cells. Doxorubicin-loaded QD-ILs showed efficient anticancer activity, while no cytotoxicity was observed for QD-ILs without chemotherapeutic payload. In athymic mice, QD-ILs significantly prolonged circulation of QDs, exhibiting a plasma terminal half-life ( t 1/2) of approximately 2.9 h as compared to free QDs with t 1/2 < 10 min. In MCF-7/HER2 xenograft models, localization of QD-ILs at tumor sites was confirmed by in vivo fluorescence imaging. 相似文献
74.
PURPOSE: Spitting as an ictal automatism has been rarely reported. We aimed to establish its potential lateralizing and localizing significance. METHODS: Review of patients undergoing surgery for intractable epilepsy at two comprehensive epilepsy centers. RESULTS: Five patients were found who had spitting as a stereotyped automatism of their complex partial seizures. All had evidence of right temporal ictal onset and underwent resective surgery. Two had tumors; one, a cavernous angioma; one, hippocampal gliosis, and one, hippocampal sclerosis. We found no instances of ictal spitting in patients with left hemisphere onset. CONCLUSIONS: Spitting as an automatism in complex partial seizures, although uncommon, may be a localizing sign to the nondominant temporal lobe. 相似文献
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Kinicki Angelo J.; Lockwood Chris A.; Hom Peter W.; Griffeth Rodger W. 《Canadian Metallurgical Quarterly》1990,75(5):477
The relative effects of varied interviewee cues on line managers' hiring decisions were examined, as was the relative predictability of various criteria by line managers' interview impressions. Aggregate and individual regression analyses revealed that 3 nursing directors' impressions of 186 nursing applicants shaped their hiring recommendations more than did the applicants' resume credentials. Moreover, managers' interview impressions significantly predicted employees' job attitudes, though predictions of attitudes did not exceed predictions of performance. Finally, individual managers based hiring decisions on different interview impressions, and these impressions forecast employees' job attitudes with differential validity. Implications for future interviewing research are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
79.
G Johnson PW Burvill CS Anderson K Jamrozik EG Stewart-Wynne TM Chakera 《Canadian Metallurgical Quarterly》1995,91(4):252-257
Evaluation of the relative efficacy of three screening instruments for depression and anxiety in a group of stroke patients was undertaken as part of the Perth community stroke study. Data are presented on the sensitivity and specificity of the Hospital Anxiety and Depression Scale (HAPS), the Geriatric Depression Scale and the General Health Questionnaire (GHQ) (28-item version) in screening patients 4 months after stroke for depressive and anxiety disorders diagnosed according to DSM-III criteria. The GHQ-28 and GDS but not the HADS depression, were shown to be satisfactory screening instruments for depression, with the GHQ-28 having an overall superiority. The performance of all 3 scales for screening post-stroke anxiety disorders was less satisfactory. The HADS anxiety had the best level of sensitivity, but the specificity and positive predictive values were low and the misclassification rate high. 相似文献
80.
OBJECTIVE: A summary about the final results of the Hungarian double-blind placebo controlled randomised trial of periconceptional folic acid containing multivitamin and trace element supplementation. RESULTS: The major finding is a significant prevention of the first occurrence of neural-tube defect, urinary tract and cardiovascular defects, in addition a decrease in the rate of limb deficiencies and congenital hypertrophic pyloric stenosis. Fertility was slightly improved and the rate of twins increased significantly after periconceptional multivitamin supplementation. The effect of multivitamin supplementation for fetal death is controversial, but in general there is no clinically significant change. Periconceptional multivitamin supplementation can reduce the occurrence of nausea and vomiting. PRACTICAL IMPLEMENTATIONS: Consumption of foods which are rich in folate may not be the best way to prevent neural-tube defects and other congenital abnormalities. Periconceptional multivitamin supplementation is part of the periconceptional care in Hungary and it is an appropriate forum for the practical delivery for this primary prevention action. However, as a large proportion of pregnancies are unplanned, the widespread use of bread fortified with folic acid, vitamin B12 and B6 may decrease a considerable part of neural-tube defects and some other congenital abnormalities, in addition to vascular diseases due to hyperhomocysteinemia. 相似文献