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201.
The laser evaporation method is an attractive technology to synthesize composite materials. We tried to apply the laser evaporation method on fabrication of CdTe-doped glasses for the first time. CdTe microcrystallites embedded in SiO2 films were confirmed by transmission electron microscope images. The third-order nonlinear susceptibility χ(3) and the decay time τ of CdTe-doped glasses were measured by three-beam forward type degenerate four-wave mixing. The maximum value of χ(3) was estimated 4.2 x 10-7 esu when the absorption coefficient was 6000 cm-1. From the limitation of pulse duration of 5 ps, τ was not exactly measured but imagined to be shorter than 10 ps, which was much faster than the other semiconductor-doped glasses ever reported. The figure of merit defined as χ(3)/τ is probably larger than 7.  相似文献   
202.
OBJECTIVES: Preeclampsia is characterized by an increase in vascular tone associated with reduced uteroplacental flow. The nature of hypertension arising in pregnancy suggests that the abnormal increase in blood pressure is dependent on some humoral factor that mediates vasospasm. There is evidence that preeclampsia results from a breakdown in the balance between vasodilators such as prostacyclin and prostaglandin E2 and nitric oxide and the vasoconstrictors angiotensin II, thromboxane A2, serotonin, and endothelin. Furthermore, vascular reactivity to angiotensin II is greatly enhanced in preeclampsia as opposed to normal pregnancies. The increased vascular tone and the enhanced thromboxane production noted in preeclampsia may be mediated by the increased sensitivity to angiotensin II because angiotensin II coupled to an AT1 receptor is a potent vasoconstrictor and stimulates the accumulation of free arachidonic acid, the precursor of thromboxane and the prostaglandins. STUDY DESIGN: We used a rat model that has been shown to express the relevant clinical features of human preeclampsia to investigate the involvement of the AT1 angiotensin receptor in this pathologic condition. Pregnant rats were divided into three groups that were either infused with saline or endotoxin on the 14th day of pregnancy. One of the endotoxin-infused groups was further treated with the AT1-selective antagonist losartan from day 11 until day 19 of pregnancy. RESULTS: Perinatal outcome, blood pressure, and urine protein were monitored for each group. We observed that endotoxin infusion resulted in a decrease in pup weight and number of pups and caused an increase in mean arterial pressure as well as increased proteinuria when compared with saline solution-infused animals. In contrast, endotoxin-infused rats receiving losartan exhibited no change in number or weight of pups when compared with control, and losartan tended to diminish the rise in mean arterial pressure. In addition, the increase in urinary protein excretion was completely blocked by losartan. CONCLUSIONS: Endotoxin infusion in pregnant rats appears to be a suitable model for the study of preeclampsia. Moreover, the angiotensin II-dependent activation of an AT1 receptor appears to mediate a portion of the pathophysiologic features associated with preeclampsia.  相似文献   
203.
CD31 is a specific and sensitive marker of endothelial differentiation. Previous reports have described its immunoreactivity in large series of soft tissue neoplasms, as well as its comparison with other available and commonly used endothelial markers. CD31 reactivity in carcinomas or mesotheliomas has been incompletely addressed, however. Hence, we applied anti-CD31 (JC70/A, DAKO, Carpinteria, Calif) to 290 previously characterized neoplasms by using a modified avidin-biotin-peroxidase complex technique following microwave epitope retrieval. Seven carcinomas showed plasmalemmal-based immunoreactivity (2 papillary thyroid carcinomas, 2 mucoepidermoid salivary gland carcinomas, 1 cutaneous adnexal tumor, 1 cutaneous squamous cell carcinoma, and 1 esophageal squamous cell carcinoma); the remaining 283 lesions were negative for this marker. We conclude that anti-CD31 immunostaining in carcinomas and mesotheliomas is rare. These findings support the concept that CD31 is a reliable marker of endothelial differentiation and should be included in diagnostic immunohistochemical panels when vascular tumors enter the differential diagnosis.  相似文献   
204.
A numerical study is presented of the flow characteristics in a gas-agitated water bath in the presence of a top layer of dissimilar fluid. Two systems are considered, comprised separately of silicon and normal pentane as the top layer, to simulate slag cover in a real steelmaking process. The mathematical model involves solution of transport equations for the variables of each phase, with allowance for interphase transfer of momentum. Turbulence is assumed to be a property of the carrier (liquid) phase and represented through solution of additional transport equations for the turbulence kinetic energy, k, and its rate of dissipation, ɛ. The model also accounts for turbulence modulation by the bubbles through enhancement of the source terms in the equations for k and ɛ. The predicted mean and fluctuating velocities, stresses, and turbulence production are generally in the consensus of the experimental data. Both mean flow and turbulence characteristics are found to be suppressed in the water/silicon system of smaller density ratio, indicating enhanced re-entrainment of the top layer, than the water/normal pentane system.  相似文献   
205.
Building on Ben-Avi and Winter’s (2007) work, this paper provides a general “intensionalization” procedure that turns an extensional semantics for a language into an intensionalized one that is capable of accommodating “truly intensional” lexical items without changing the compositional semantic rules. We prove some formal properties of this procedure and clarify its relation to the procedure implicit in Montague’s (1973) PTQ.  相似文献   
206.
Estimating blood content in the lung remains a key step in calculating lung water volume and microvascular permeability. We studied the effect of regional lung hematocrit (Hct) variation on assessment of acute lung injury. Escherichia coli endotoxin was administered in guinea pigs intravenously. Lung injury was evaluated by measuring the wet-to-dry weight ratio (W/D) and transvascular 125I-labeled albumin leakage for 3 h [tissue-to-plasma 125I-albumin ratio (T/P)] in five tissue samples from each animal. Residual blood content was corrected using either 51Cr-red blood cells as a blood cell marker, 99mTc-albumin as a plasma marker, or both, injected 10 min before the guinea pigs were killed. Lung Hct, estimated from the marker counts of lung and peripheral blood samples, was lower than peripheral blood Hct; intraindividual variation, represented by the standard deviation in each subject, was 0.024 +/- 0.015 for the control group (coefficient of variation 8.0 +/- 5.1%) and 0.026 +/- 0.013 for the endotoxin group (coefficient of variation 8.5 +/- 4.1%). Uncorrected W/D for residual blood content was greater than the corrected W/D. 99mTc-albumin correction gave values closer to the W/D corrected by both markers. T/P corrected by 99mTc-albumin showed smaller data variations than the values obtained with 51Cr-red blood cell correction, which was affected by variations in lung Hct. We recommend using a plasma marker to correct for blood content in assessing acute lung injury by W/D and T/P.  相似文献   
207.
Carbamoylphosphate synthetase I (CPS I), a urea cycle enzyme, is located almost exclusively in the mitochondria of hepatocytes. The enzyme is unique in that it constitutes about 2-6% of total liver protein and is composed of a large subunit of 160 kD. We developed a sensitive enzyme-linked immunosorbent assay (ELISA) for measurement of the enzyme in plasma using an antibody against the rat enzyme. In galactosamine-induced rat acute hepatitis, plasma concentration of CPS I that was 1-2 micrograms/ml blood before the treatment, increased up to 125 micrograms/ml blood in 24 h after the treatment and decreased to a near control level in 72 h. Plasma concentration of ornithine carbamoyl-transferase (OCT), another urea cycle enzyme, reached a maximum in 24 h and then decreased a little more rapidly than that of CPS I. On the other hand, alanine aminotransferase activity reached a maximum in 36 h and decreased to a normal level in 96 h. In immunoblot analysis, the native CPS I polypeptide of 160 kD and its fragments of 140 and 125 kD were detected 24-48 h after the treatment. When purified rat CPS I and bovine OCT were injected intravenously into rats, the enzymes disappeared from blood roughly exponentially with apparent half-lives of about 67 and 18 min, respectively. Development of an ELISA for human CPS I and determination of the serum enzyme in various liver diseases remain to be performed.  相似文献   
208.
In order to understand an apparent discrepancy of concentration of constituent elements in the quantitative analysis of thin KCl crystals with an energy dispersive X-ray analyzer, which has been partly explained by fluorescent X-ray excitation, more detailed experiments were carried out on binary alkali halides and tricomponent amorphous material by changing the azimuthal angle. Intensity ratios of X-rays from the constituent elements in KCl and KBr single crystals varied considerably according to the rotation of the specimens. The observed differences between maximum and minimum intensity ratios were 15% for a thin KCl crystal about 100 nm thick and 20% for a bulk KCl crystal, which corresponded to 4.1% and 4.5% differences in atomic concentration, respectively. It was ascertained that for amorphous materials such as Co87Zr5Nb8, such a variation of the intensity ratio of X-rays was not observed. It is thus proved that the variations of the intensity ratios of X-rays from the constituent elements with azimuthal angle for KCl and KBr are attributed to the diffraction effect of characteristic X-rays generated in crystalline specimens. This effect, which is the same as that in the production of Kossel patterns, is one of the essential factors limiting the accuracy of the analysis.  相似文献   
209.
We generated interleukin-5 receptor alpha chain (IL-5R alpha)-deficient (IL-5R alpha-/-) mice by gene targeting. The IL-5R alpha-/- mice showed decreased numbers of B-1 cells concomitant with low serum concentrations of IgM and IgG3. They showed no IL-5-induced enhancement of B cell responses to T-independent antigens. The number of alpha beta T cell receptor-positive thymocytes tended to decrease in 3-week-old IL-5R alpha-/- mice, returning to normal by 6 weeks of age. The IL-5R alpha-/- mice produced basal levels of eosinophils, while their bone marrow cells failed to form eosinophilic colonies in response to IL-5. Impaired eosinophilopoiesis in IL-5R alpha-/-mice enhanced the survival of Angiostrongylus cantonensis. These results indicate that IL-5-induced eosinophils serve as potent effector cells in the killing of Angiostrongylus cantonensis in mice.  相似文献   
210.
An investigation of the reduction of magnesia by aluminum was carried out using a nonisothermal gravimetric technique under an argon atmosphere, in the temperature range from 1273 to 1873 K. The mixture of magnesia and aluminum powders was formed into a pellet under various isostatic pressures. It was found that magnesia is reduced by aluminum to form magnesium and spinel at first, and then the excess aluminum reacts with spinel slowly. The temperature at which the reaction starts increases with an increasing heating rate. The reaction rate is also affected by pellet-forming conditions. A kinetic model is proposed to explain the experimental results. The activation energy of the reduction of magnesia by aluminum is 151.2 kJ/mol. Good agreement between calculated and experimental results is obtained.  相似文献   
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