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排序方式: 共有592条查询结果,搜索用时 15 毫秒
41.
42.
Temperature effects on very slow desorption of native chlorobenzenes from sediment to water 总被引:2,自引:0,他引:2
ten Hulscher TE Vrind BA van Noort PC Govers HA 《Environmental toxicology and chemistry / SETAC》2004,23(7):1634-1639
The temperature dependence of the kinetics of very slow desorption of eight chlorobenzenes was studied in laboratory batch experiments on a field-contaminated sediment from Lake Ketelmeer, The Netherlands. The observed rate constants for very slow desorption averaged (1.5 +/- 0.4) x 10(-4)/h at 10 degrees C, (2.9 +/- 1.0) x 10(-4)/h at 20 degrees C, (5.8 +/- 2.4) x 10(-4)/h at 35 degrees C, and (6.4 +/- 3.0) x 10(-4)/h at 45 degrees C over all eight compounds. Activation energies for desorption to water were close to the enthalpy for dissolution of the pure solid in water. The activation energies ranged from 18 to 53 kJ/mol with an average of 36 +/- 11 kJ/mol. These values confirm earlier reported activation energies for very slow desorption to water. They are much less than values for activation energies for desorption to the gas phase. That difference can be explained in terms of rate limiting desorption from carbonaceous adsorption sites. 相似文献
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van den Bosch MA Mali WP Bloemenkamp DG Eikelboom BC Kemmeren JM Tanis BC Algra A Rosendaal FR van der Graaf Y 《Atherosclerosis》2002,164(1):121-127
BACKGROUND: During clinical evaluation of young women with peripheral arterial occlusive disease, we were surprised by the high prevalence of pregnancy loss in women with segmental stenosis confined to the aortoiliac segment. We wondered if increased occurrence of miscarriage is the result of high expression of vascular and obstetrical risk factors in these patients, or if it is related to localization of disease. In a case-control study designed to investigate risk factors for peripheral arterial occlusive disease in young women, we assessed the risk of miscarriage in these patients according to level of obstruction. METHODS: A total of 202 female patients, aged 18-49 years and 466 healthy control women from a population based case-control study, donated venous blood samples and filled out a structured questionnaire concerning classical cardiovascular risk factors and obstetrical history. In all patients, diagnosis of peripheral arterial occlusive disease was confirmed by intra-arterial angiography. Patients were classified into two groups: those with and those without stenosis of the aortoiliac segment (aortoiliac disease). RESULTS: In 77 of the 202 patients (38%) with peripheral arterial occlusive disease, the obstruction was confined to the aortoiliac segment. The occurrence of miscarriage was high (42%) in young women with aortoiliac disease. Compared to healthy controls, the risk of miscarriage increased 3-fold (OR 3.1; 95% CI 1.8-5.6) in these patients. Adjustment for obstetrical and vascular risk factors did not affect the risk estimate. CONCLUSION: This is the first study that identifies aortoiliac disease as a risk factor for pregnancy loss in young women. The risk of miscarriage is increased 3-fold in women with aortoiliac disease. The presence of vascular and obstetrical risk factors did not affect the strength of the association. Pregnancy loss could be the first sign of insufficient aortic circulation in these patients. 相似文献
45.
El-Sayegh S Bea S Agelopoulos A 《Cleveland Clinic journal of medicine》2003,70(10):824-5, 829-30, 832-3, passim
Obsessive-compulsive disorder (OCD) is the fourth most common psychiatric disorder. Yet patients often avoid seeking help because they are ashamed. Diagnosis is difficult, but familiarity with the nature of OCD and its current management helps primary care physicians identify patients with OCD and make informed judgments about treatment and referral. We review common symptoms, causes, drug therapy, behavioral therapy, and quality of life issues in patients with OCD. 相似文献
46.
Vuylsteke A Davidson HJ Ho WS Ritchie AJ Callingham BA White R Hiley CR 《Journal of cardiovascular pharmacology》2001,37(4):394-405
The actions of the blood substitute diaspirin crosslinked hemoglobin (DCLHb) were investigated in rat (small mesenteric artery) and human (radial collateral artery) resistance vessels mounted in a wire myograph for isometric tension recording. DCLHb did not contract resting vessels from rats, but vasoconstrictor responses were observed in isolated arteries and perfused mesenteric beds prestimulated with threshold concentrations of methoxamine. The DCLHb contractile responses were greatly attenuated by N(G)-nitro-L-arginine methyl ester hydrochloride (L-NAME) or endothelial removal, whereas BQ-123 (endothelin A receptor antagonist), prazosin (alpha1-adrenoceptor antagonist), or indomethacin (cyclooxygenase inhibitor) had no effect. Endothelium-dependent relaxations to carbachol in both rat mesenteric and human radial collateral artery were inhibited by DCLHb. Relaxations to carbachol were studied in the presence of L-NAME or 25 mM KCl to investigate the effect of DCLHb on endothelium-derived hyperpolarizing factor (EDHF) and nitric oxide, respectively. In both rat and human vessels, EDHF-mediated relaxations were not affected by DCLHb preincubation, whereas the nitric oxide component of carbachol-induced relaxations was practically abolished. In conclusion, inhibition of the effects of basal nitric oxide release underpins the vasoconstrictor effects of DCLHb. DCLHb effectively abolishes the nitric oxide component of carbachol-induced relaxation, with no effect on the EDHF-mediated component in both isolated rat mesenteric and human radial collateral arteries. 相似文献
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H van Loon V Saverys J P Vuylsteke R F Vlietinck R Eeckels 《Annals of tropical paediatrics》1986,6(1):79-92
Anthropometric data of 12,769 clinically normal children 0-6 years of age from 12 different geographical areas in Africa and Asia are presented. Height, weight, arm circumference and triceps skinfold thickness were measured and presented for age. Derived variables, as muscle circumference, muscle area and muscle proportion-for-age were computed. Weight, arm circumference and muscle area-for-height were calculated. Comparison of these 12 cross-sectional growth patterns shows important differences between groups. The observed differences show that height-for-age, weight-for-age, arm circumference-for-age and weight-for-height are not sufficient to describe adequately and to interpret the variations in nutritional status. 相似文献
49.
Manuel Rodriguez‐Perdigon Rosa María Tordera Francisco Javier Gil‐Bea Gorka Gerenu Maria Javier Ramirez Maite Solas 《Hippocampus》2016,26(10):1303-1312
Alzheimer's disease (AD) is characterized phenotypically by memory impairment, histologically by accumulation of pTau and β‐amyloid peptide and morphologically by a loss of nerve terminals in cortical and hippocampal regions. As glutamate is the principle excitatory neurotransmitter of the central nervous system (CNS), the glutamatergic system may play an important role in AD. To date, not many studies have addressed the deleterious effects of Aβ on glutamatergic terminals; therefore the aim of this study was to investigate how Aβ affects glutamatergic terminals and to assess the extent to which alterations in the glutamatergic neurotransmission could impact susceptibility to the illness. The present study shows that Aβ caused a loss of glutamatergic terminals, measured by VGLUT1 protein levels, in Tg2576 primary cell cultures, Tg2576 mice and AD patient brains, and also when Aβ was added exogenously to hippocampal cell cultures. Interestingly, no correlation was found between cognition and decreased VGLUT1 levels. Moreover, when Aβ1–42 was intracerebroventricularlly administered into VGLUT1+/‐ mice, altered synaptic plasticity and increased neuroinflammation was observed in the hippocampus of those animals. In conclusion, the present study not only revealed susceptibility of glutamatergic nerve terminals to Aβ induced toxicity but also underlined the importance of VGLUT1 in the progression of AD, as the decrease of this protein levels could increase the susceptibility to subsequent deleterious inputs by exacerbating Aβ induced neuroinflammation and synaptic plasticity disruption. © 2016 Wiley Periodicals, Inc. 相似文献
50.
Ruth Van Looveren Yannick Mandeville Pieter Logghe Katrien Vandendriessche Xander Verbeke Patrick Vuylsteke Paul Pattyn Bart Smet 《Obesity surgery》2018,28(3):665-670