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91.
92.
U Kapil N Saxena S Ramachandran TD Sharma D Nayar 《Canadian Metallurgical Quarterly》1997,34(4):338-340
Using polymerase chain reaction single strand conformational polymorphism (PCR-SSCP) and EB staining technique, paraffin-embeded sections of 20 hydatidiform mole and 4 choriocarcinoma were detected in the exons 5 and 8 of p53 gene. The results showed that mutations of p53 gene were 0/9 in the normal chorionic villi, 6/20 (30%) in hydatidiform mole and 3/4 in choriocarcinoma. This study suggests that mutations of p53 gene may be an important event in human gestational trophoblastic neoplastigenesis and its progression. 相似文献
93.
RB Stevens DE Sutherland JD Ansite M Saxena TJ Rossini BK Levay-Young BJ Hering CD Mills 《Canadian Metallurgical Quarterly》1997,159(11):5329-5335
Evidence in this paper indicates that insulin can down-regulate the inducible nitric oxide synthase (iNOS) pathway in vivo. The iNOS pathway is up-regulated in diabetes-prone rats and mice and is associated with an autoimmune process. However, the results presented here indicate that macrophage nitric oxide (NO) production and iNOS mRNA expression are also elevated in rats or mice made diabetic by streptozotocin injection in which there is no primary autoimmune component. Insulin administration reduces NO production in autoimmune-prone and streptozotocin-induced diabetic rodents. Finally, insulin decreases macrophage NO production in normal hosts. These results indicate that the autoimmune paradigm is inadequate to explain increased NO in diabetes. As a potential mechanism to explain insulin-mediated regulation of NO production, TGF-1 may be involved because 1) macrophages from diabetic mice produce less TGF-beta1 than macrophages from normal hosts; 2) the circulating TGF-beta1 level is lower in diabetic mice; and 3) insulin administration increases circulating TGF-beta1 in normal mice. Together, these results provide evidence that increased NO in diabetes is not only a cause but also an effect of beta-cell destruction and results in part from a heretofore unrecognized immunomodulatory activity of insulin. 相似文献
94.
The mutagenic and genotoxic potential of four pesticides viz. captan, foltaf, phosphamidon and furadan was evaluated by the Ames mutagenicity assay and their DNA damaging ability on radiation repair defective E. coli K-12 strains respectively. The mutagenic spectrum revealed captan to be most mutagenic in the absence of metabolic activation, while the presence of S9 mix led to an attenuated mutagenic response. Foltaf, phosphamidon and furadan were detected as relatively weaker mutagens. A significant decrease in the survival of SOS defective mutants, recA, lexA and pol- of E. coli was observed as compared to their wild-type counterparts in the presence of the pesticides. The role of SOS repair genes gains further support from the Salmonella strains triggering the error-prone SOS response. 相似文献
95.
AD Min R Saxena SN Thung EO Atillasoy DC Wolf B Sauter ME Schwartz HC Bodenheimer 《Canadian Metallurgical Quarterly》1998,93(11):2148-2153
OBJECTIVE: Hepatitis C virus (HCV) infection is associated with development of hepatocellular carcinoma (HCC). The aim of this study was to examine clinical characteristics and outcome of patients with HCV with or without HCC undergoing liver transplant. METHODS: We reviewed the charts of all 55 patients transplanted between November 1990 and December 1996 for HCV cirrhosis with HCC and compared them with a control group of HCV patients without HCC. Patients with a history of alcohol abuse or HBsAg positivity were excluded. There were 37 men and 18 women, with a mean age of 57.6 yr (range, 19-70 yr) in the HCC group. RESULTS: There was no significant difference between the HCC and nonHCC groups regarding Child's class or United Network for Organ Sharing (UNOS) status at the time of transplant. Twenty-six (45%) patients were diagnosed or suspected of having HCC before transplant. Twenty-five patients (45.5%) had a single focus of HCC. Fourteen percent (seven of 50) of the patients with HCC had been treated with interferon, whereas 12% (six of 52) of patients in the nonHCC group had received interferon. Duration of interferon therapy ranged from 1 to 9 months. All interferon treatment occurred within 5 yr of transplant. A history of intravenous drug use or transfusion was identified in 37 (67%) of HCC patients. Thirty-two patients (58%) without HCC had a parenteral exposure. There was no significant difference in patient or graft survival rates between the patients with and without HCC. CONCLUSION: Approximately one-half of HCC was not detected before liver transplant. There was no significant difference in the mode of transmission, clinical status at the time of transplant, or outcome between the HCV patients with and without HCC. 相似文献
96.
Genetic analysis of the population structure of the western blacklegged tick, Ixodes pacificus Cooley & Kohls, was conducted using allozymes. This vector tick transmits the Lyme disease spirochete, Borrelia burgdorferi Johnson, Schmid, Hyde, Steigerwalt & Brenner, in the far-western United States. It ranges from British Columbia to Baja California and disjunct populations are present in Oregon, Nevada, Utah, and Arizona. Host-seeking adult ticks were collected from vegetation across the range of the species and were partially fed on rabbits prior to analysis. Twelve putative loci were resolved using starch gel electrophoresis. One locus, glucose-6-phosphate isomerase, formed an apparent north/south latitudinal cline and showed significant geographic structure. None of the remaining loci exhibited much genetic differentiation. Estimates of gene flow were high relative to other arthropods. Isolation-by-distance analysis suggests a recent and rapid range expansion. We conclude that the overall lack of differentiation is due high rates of gene flow. 相似文献
97.
The organometallic vapor phase epitaxial (OMVPE) growth of GaSb and GaAsl−xSbx (0 ≤ × ≤ 0.26, 0 .64 ≤ × ≤1) is discussed. Trimethylgallium and trimethylantimony are used as the Ga and Sb source, respectively.
Most GaAs1× Sbx growths are done using arsine, but the use of an alternate arsenic source, trimethylarsenic, is also discussed. In contrast
to most arsenic-containing alloys, both GaSb and Sb-rich GaAs1−x Sbx are grown under Group III-rich conditions. The total input flux as well as the ratio of the input chemicals must be closely
regulated. In particular, growth of GaAsl−xSbx requires careful control of the trimethylantimony-to-total Group V ratio, since arsenic preferentially incorporates into
the crystal.
This work was supported by DOE through the Division of Materials Science Branch of the Office of Basic Energy Sciences under
Contract No. DE-AC03-79SF10610. 相似文献
98.
Daylight contribution at a point due to sky visible through different areas of a window is a function of the sky luminance, the projected solid angle of these areas at the reference point on the working plane and the transmittance of glass. The transmittance of glass varies considerably with the angle of incidence, which depends upon the relative positions of different parts of a window opening with respect to the reference point. A sky component grid, representing the sky component values from different elemental areas of openings in a window wall, forms one of the simplest ready reckoners in daylighting design. This paper presents the methodology of generating sky component grid for any sky condition. The relevant data on mean altitude of grid elements, the mean angle of incidence for different grid elements, and differential sky factors are included for facilitating the computation of grid values. The sky component grid for Indian clear design sky based on exact equations of sky component for a horizontal plane, with a due allowance for transmittance of 3 mm thick clear glass, is provided for comparing the accuracy of the methodology based on differential sky factors. The values computed from the data and the methodology presented in this paper agree closely with the exact values. The deviation of computed values from exact values is less than ±10%. 相似文献
99.
Saxena N.R. Robinson J.P. 《IEEE transactions on information theory / Professional Technical Group on Information Theory》1988,34(1):64-69
In the testing of logic circuits, two proposed data-compression methods use the number of ones (syndrome) and the number of sequence changes (transition count). An enumeration N (m , k , t ) of the number of length-m binary sequences having syndrome value k and transition count t is developed. Examination of this result reveals that the parallel compression of these two methods has small overlap in error masking. An asymptotic expression for N (m , k , t ) is developed 相似文献
100.
The composition of an incinerator flue gas depends characteristically on the operating parameters such as combustion temperature, fractional excess air value, and moisture content of the waste material. An a priori knowledge of the influence of these parameters on the flue-gas composition helps to carry out the combustion process efficiently by appropriately selecting their values. A simple chemical equilibrium model is proposed to predict the flue-gas composition from an incinerator at different operating temperatures, excess air values, and moisture contents of the combusting material. The predicitions are supposed to establish the upper limit of the chemical species concentrations in the flue gas and hence the model is considered as an appropriate one for selecting the pollution control equipment and in estimating the upper limit of environmental contamination. The model-based computations predict that at a given temperature and moisture content, the increase in excess air decreases the concentrations of carbon monoxide, carbon dioxide, water, and hydrogen in the flue gas while it increases that of oxygen. Similarly, the proportion of nitrogen dioxide, nitrogen, sulfur dioxide and sulfur trioxide decreases while that of nitric oxide increases. At a given excess air and moisture content, the increase in temperature decreases the concentrations of carbon monoxide and hydrogen and increases of carbon dioxide and water due to better combustion. Similarly, the increase in temperature also augments the concentrations of nitric oxide, nitrogen dioxide and sulfur dioxide while it decreases that of nitrogen and sulfur trioxide. Similar trends are observed at different levels of moisture content. 相似文献