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排序方式: 共有368条查询结果,搜索用时 15 毫秒
91.
P Nilsson H Lundgren M S?derstr?m KO Fagerstr?m P Nilsson-Ehle 《Canadian Metallurgical Quarterly》1996,240(4):189-194
MIB-1 Ki-67 and PCNA scores in infiltrating ductal NOS breast carcinomas were compared. The correlation between MIB-1, Ki-67 and PCNA indices and several clinicopathological factors that have prognostic significance in breast cancer was also assessed. The mean Ki-67, MIB-1 and PCNA indices were 13.4%, 19.4%, 27.6%, respectively. Significant positive linear correlation was found only between Ki-67 and MIB-1 indices. PCNA score did not correlate with Ki-67 and MIB-1 indices. The significant correlation between Ki-67 and MIB-1 scores and histological grade was found. There was no correlation between Ki-67 and MIB-1 indices and axillary lymph node status or tumor diameter. The results suggest that MIB-1 antibody is an excellent tool for assessment of proliferative rate of breast cancer cells in paraffin sections. 相似文献
92.
93.
A reevaluation of the original buoyant density conversion formula used to calculate the molar percentage guanosine + cytosine (% G + C) contents of the accepted species of genus Desulfovibrio has been undertaken. It would appear that the formula used gives values 4-5% lower than those obtained using formulae more generally cited in modern literature. Recalculations of % G + C content values for Lesulfovibrio DNA are presented using the formulae of three different workers, and are compared with those values originally used in the classification of genus Desulfovibrio. 相似文献
94.
95.
Kuster WC Jobson BT Karl T Riemer D Apel E Goldan PD Fehsenfeld FC 《Environmental science & technology》2004,38(1):221-228
The Texas Air Quality Study 2000 (TexAQS2000) investigated the photochemical production of ozone and the chemistry of related precursors and reaction products in the vicinity of Houston, TX. The colocation of four instruments for the measurement of volatile organic carbon compounds (VOCs) allowed a unique opportunity for the intercomparison of the different in-situ measuring techniques. The instruments included three gas chromatographs, each with a different type of detector, and a Proton-Transfer-Reaction Mass Spectrometer (PTR-MS) with each system designed to measure a different suite of VOCs. Correlation plots and correlation statistics are presented for species measured by more than one of these instruments. The GC instruments were all in agreement to within 10-20% (slope) with coefficients of variation (r2) of > or = 0.85. The PTR-MS agreement with other instruments was more dependent on species with some very good agreements (r2 values of approximately 0.95 for some aromatics), but isoprene, acetaldehyde and propene were substantially less highly correlated (0.55 < r2 < 0.80). At least part of these differences were undoubtedly due to the timing of sample acquisition in an environment in which VOC levels changed very rapidly on both quantitative and temporal scales. 相似文献
96.
介绍了适用于尼龙(PA)基材的新型前处理工艺.经过膨胀、调校、钯活化、还原、化学镍(δ=0.3 μm)、预镀镍或铜(δ=2~5 μm),酸铜(δ=20 μm),光亮镍(δ=12 μm)、装饰铬(δ=0.3μm)等工艺后,可在尼龙表面获得结合力良好的装饰性镀层.该工艺为开发尼龙塑料在电镀业的应用迈出了重要的一步. 相似文献
97.
Rajesh?S.?Somani Chang?Hyun?KO Sang?Sup?Han Soon?Haeng?ChoEmail author 《Journal of Porous Materials》2005,12(2):87-94
Mesoporous silica with pore sizes of 3–6 nm has been synthesized under refluxing and autogenous pressure conditions of hydrothermal synthesis from precursor gels having different alkaline pH. The mesoporous silica prepared is characterized by powder X-ray diffraction, nitrogen adsorption-desorption measurement and scanning electron microscopy. Thermal stability has been tested by XRD analysis of mesoporous silica after thermal treatment at 823 K, 6 h; 1023 K, 1 h and 1223 K, 1 h. The results indicate that the mesoporous silica prepared under refluxing condition from precursor gel of pH 11 has large surface area (ca.1103 m2 g− 1) and pore volume (ca. 0.868 cm3 g− 1) and is thermally stable at 1223 K. The surface area, pore volumes and pore wall thickness increase as the pH of the precursor gel is increased for refluxing condition of synthesis. The comparison of textural properties revealed that the refluxing condition is advantageous over autogenous pressure condition for obtaining mesoporous silica with higher surface area (852 m2 g− 1), pore volume (0.894 cm3 g− 1) and pore diameter > 4 nm with wall thickness of 1.59 nm, when synthesized from precursor gel of pH 9.2. The 29Si NMR spectra showed that a great part of the Si atoms exists as silanol groups. The mesoporous silica made at the lower pH (9.2) under refluxing conditions have more condensed framework. In calcined mesoporous silica, the proportion of partly condensed silica (Q3) is higher than fully condensed silica (Q4). 相似文献
98.
This paper outlines computer analyses to predict thermal-hydraulics, flow-induced vibration, and fretting-wear damage in shell-and-tube heat exchangers. The analytical techniques are briefly described and the results arc illustrated by example. It is concluded that computer techniques can do much to improve the reliability and performance of heat exchangers. 相似文献
99.
Comparative studies on the electrical properties of a metal-ferroelectric-insulator-semiconductor field effect transistor were conducted using pulsed laser ablated ferroelectric Bi3.25La0.75Ti3O12 (BLT) thin films deposited on SiO2/Si substrates with different SiO2 thicknesses. The SiO2 layer was prepared on n-type Si substrates by dry oxidation at a temperature of 800°C. Small angle x-ray reflectivity studies were used to measure the SiO2 thickness. The capacitance-voltage (C-V) measurements revealed that the films showed good interfacial properties. Shifts in flatband voltages were observable, but were effectively reduced by deposition of the ferroelectric films. Au/BLT/SiO2/Si diodes with 8 nm SiO2 layer showed to be stable with relatively large memory window values of about 0.3 V, 2.5 V, 5.0 V, and 7.0 V, at increasing bias voltages of ±5 V, ±7 V, ±10 V, and ±12 V, respectively. 相似文献
100.
KO Odunsi LL Peck EI Kohorn V Parkash B Cracchiolo JT Chambers KJ Taylor 《Canadian Metallurgical Quarterly》1998,70(1):100-104
OBJECTIVE: In normal pregnancy and pregnancies complicated by preeclampsia it has been demonstrated that there is increased activation of platelets and the clotting and fibrinolytic system. We measured plasma levels of thrombopoietin, a major regulator of platelet production in these conditions. STUDY DESIGN: We compared the thrombopoietin plasma levels of healthy term pregnant patients (n = 21) with those of healthy nonpregnant controls (n = 17), as well as patients with severe preeclampsia (n = 8) and the hemolysis, elevated liver enzymes, low platelets syndrome (n = 6). RESULTS: Thrombopoietin levels in normal pregnant patients and pregnancies complicated by the hemolysis, elevated liver enzymes, low platelets syndrome were statistically significantly higher than thrombopoietin levels in nonpregnant controls. Data were analyzed with the Kruskal-Wallis one-way analysis of variance by ranks. CONCLUSIONS: This study is the first to report thrombopoietin levels in pregnancy. Thrombopoietin levels are significantly greater in pregnant patients and in pregnancies complicated by the hemolysis, elevated liver enzymes, low platelets syndrome compared with nonpregnant controls. 相似文献