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151.
TV Gurvits ME Shenton H Hokama H Ohta NB Lasko MW Gilbertson SP Orr R Kikinis FA Jolesz RW McCarley RK Pitman 《Canadian Metallurgical Quarterly》1996,40(11):1091-1099
This study used quantitative volumetric magnetic resonance imaging techniques to explore the neuroanatomic correlates of chronic, combat-related posttraumatic stress disorder (PTSD) in seven Vietnam veterans with PTSD compared with seven nonPTSD combat veterans and eight normal nonveterans. Both left and right hippocampi were significantly smaller in the PTSD subjects compared to the Combat Control and Normal subjects, even after adjusting for age, whole brain volume, and lifetime alcohol consumption. There were no statistically significant group differences in intracranial cavity, whole brain, ventricles, ventricle:brain ratio, or amygdala. Subarachnoidal cerebrospinal fluid was increased in both veteran groups. Our finding of decreased hippocampal volume in PTSD subjects is consistent with results of other investigations which utilized only trauma-unexposed control groups. Hippocampal volume was directly correlated with combat exposure, which suggests that traumatic stress may damage the hippocampus. Alternatively, smaller hippocampi volume may be a pre-existing risk factor for combat exposure and/or the development of PTSD upon combat exposure. 相似文献
152.
VM Mikha?lov VN Reushkin GD Reushkina TV Sebekina TM Smirnova 《Canadian Metallurgical Quarterly》1995,29(6):26-32
With the use of dispersion analysis the variation of indices of central and peripheral hemodynamics in healthy volunteers stayed from 1 to 7 days under conditions of "dry" immersion (DI) was studied. Nine persons were investigated at rest, 5 individuals during orthostatic tests before and after dry immersion sessions. The central hemodynamic indices were calculated, the arterial pressure (AD) was measured by Korotkoff's method, indices of rheoencephalographic and rheoplethysmographic indices of lower leg were found. The significant differences of mean values of measured parameters before and after DI at rest were not revealed. Two-factor dispersion analysis of the orthostatic test data revealed the high levels of significance of influencing immersion and personality factors as well as their interaction on the variation of most indices. For excluding an individual uniformity there has been done an analysis of dynamics of indices according to their relative values which allowed one to isolate qualitative peculiarities of changes and distinctions between persons with different orthostatic tolerance even before orthostatic testing. 相似文献
153.
Liquid carbon dioxide was studied as a solvent for the isobutane–isobutylene alkylation. The acid catalysts in the reaction were anhydrous HF (AHF), pyridinium–poly(hydrogen fluoride) complex (PPHF), concentrated sulfuric acid and trifluoromethanesulfonic acid (TFSA). The effect of the acid–hydrocarbon volume ratio, temperature and residence time on the alkylate quality were studied over the temperature range of 50 T 0 °C. Carbon dioxide as a competing weak base decreases the acidity of the system which parallels the alkylate quality. In the case of HF and TFSA catalysts, solvent CO2 increased the octane number of the alkylate product (RON 95.6 for HF and 88.0 for TFSAcatalyzed alkylation with CO2 solvent). 相似文献
154.
Takehiko Yamato Chieko Hideshima Masashi Tashiro G. K. Surya Prakash George A. Olah 《Catalysis Letters》1990,6(3-6):341-344
Nafion-H, a perfluorinated resinsulfonic acid, catalyzes condensation of acetophenones to provide 1,3,5-triarylbenzenes under relatively mild conditions. Reaction are clean, and water formed as by-product does not deactivate the catalyst. However, ortho-substituted 相似文献
155.
G.K. Surya Prakash Sujith Chacko Chiradeep Panja Tisa Elizabeth Thomas Laxman Gurung Golam Rasul Thomas Mathew GeorgeA. Olah 《Advanced Synthesis \u0026amp; Catalysis》2009,351(10):1567-1574
Solid hydrogen peroxide complexes based on poly(N‐vinylpyrrolidone) and poly(4‐vinylpyridine) were prepared and used as solid hydroxylating reagents. These solid hydrogen peroxide equivalents are found to be much safer, convenient and efficient reagent systems for the ipso‐hydroxylation of arylboronic acids to the corresponding phenols in high yields at a faster rate. The versatility of the reagents has been further expanded for the one‐pot synthesis of halophenols. Density functional theory calculations were carried out on hydrogen peroxide complexes of N‐ethylpyrrolidone and 4‐ethylpyridine as models to get a better understanding of structure and behavior of hydrogen peroxide complexes of the polymers poly(N‐vinylpyrrolidone) and poly(4‐vinylpyridine) compared to aqueous hydrogen peroxide. 相似文献
156.
G Seyoum MC Robertson TV Persaud JA Paterson RP Shiu 《Canadian Metallurgical Quarterly》1999,160(2):231-237
Rat placental lactogen-I (rPL-I), the first prolactin-like hormone expressed in the placenta during pregnancy in the rat, is known to influence maternal functions. In the present study, we have investigated the effects of rPL-I on the growth and development of cultured whole rat embryos. Rat embryos, with or without ectoplacental cone (EPC) attached, were explanted at day 9 of gestation. After 48 h of culture, the embryos, enclosed by the yolk sacs, were assessed by the presence of visible heart contractions ('heart beats'), crown-rump length (CRL) and yolk sac diameter (YSD). When intact embryos with EPC were cultured, the concentrations of rPL-I and rPL-II (products of EPC) in the medium were 850+/-841 and 92+/-181 ng/ml respectively (means+/-s.e.m.). In embryo cultures with the EPC removed, rPL-I levels decreased to=10 ng/ml, and only 70% of the embryos were viable, with visible heart beats. In the viable embryos, both CRL and embryonic DNA synthesis were reduced compared with controls, and the addition of rPL-I (1 microg/ml) did not prevent this reduction. YSD and yolk sac DNA synthesis were also reduced compared with control embryos, and the addition of rPL-I significantly prevented this decrease by 45%. In embryos cultured without EPC in the presence of neutralizing rabbit anti-rat prolactin serum (anti-rPRL), embryonic and yolk sac DNA synthesis were reduced by 35% compared with embryos exposed to normal rabbit serum. Addition of rPL-I significantly increased (P<0.05) embryonic and yolk sac growth. Thus the effects of rPL-I on embryo growth could only be seen in the absence of prolactin. The addition of human prolactin in the presence of anti-rPRL also resulted in significant increases (P<0.05) in embryonic DNA synthesis and CRL. These results suggest that rPL-I may substitute for prolactin to influence the growth of the rat embryo. 相似文献
157.
陶瓷窑炉的燃料与节能技术 总被引:1,自引:0,他引:1
本文对国内外陶瓷工业窑炉的燃料,燃烧现状及其节能技术作了简介,并对窑炉的节能效果进行评价。 相似文献
158.
以再现手指握拳的动作姿态和运动轨迹为主要目标,探讨一种带关节仿生手指的优化设计,重点讨论了手指运动矩阵的建立,预期目标的采集,仿生手指的结构模拟,确定优化目标与约束函数,求数学模型的副近解等问题。 相似文献
159.
VE Archer AD Renzetti RS Doggett JQ Jarvis TV Colby 《Canadian Metallurgical Quarterly》1998,40(5):460-474
Many uranium miners have been disabled by and died of pulmonary fibrosis that was not recognized as an occupational disease. A review of animal studies, complications from whole body irradiation, pulmonary function, and mortality studies of uranium miners led us to suspect radiation-induced chronic diffuse interstitial fibrosis in miners who had inhaled excessive radon progeny. A selected group of uranium miners (22) with severe respiratory disease (but no rounded nodules in chest films) were studied. Lung tissue from five disclosed severe diffuse interstitial fibrosis, with "honeycomb lung" in all. Some also had small anthrasilicotic nodules and birefringent crystals. Although quartz crystals probably contributed, we concluded that the predominant injurious agent in these cases was alpha particles from radon progeny. This disease, after a long latent period, usually results in pulmonary hypertension, shortness of breath, and death by cardiopulmonary failure. 相似文献
160.
Idiopathic pulmonary fibrosis (IPF) is generally defined as a progressive, fibrosing inflammatory disease of the lung parenchyma of unknown cause. It is characterized by slowly increasing dyspnea, diffuse interstitial lung infiltrates, restrictive lung dysfunction, and impaired gas exchange. Ultimately, it is fatal in most patients, and treatment options remain unsatisfactory. The advent of high-resolution computed tomography of the chest and modifications in the histopathologic classification of interstitial pneumonias have reshaped the concept of IPF. Although initially thought to be a relatively specific clinicopathologic entity, it seems likely that IPF as previously defined is a heterogeneous disorder consisting of several clinicopathologic entities with differing histopathologic patterns, clinical course, response to therapy, and prognosis. The most common histologic pattern in cases previously defined as IPF is usual interstitial pneumonia, which is associated with a median survival of less than 3 years. For accurate prognosis and optimal management of patients, the clinician should attempt to be as precise as possible in distinguishing various clinicopathologic entities that have been included under the clinical heading of IPF. In the future, we recommend that the use of the term "idiopathic pulmonary fibrosis" be restricted to patients with usual interstitial pneumonia and that clinicians recognize the fact that other idiopathic interstitial pneumonias do not have the same prognostic effect traditionally ascribed to IPF. 相似文献