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1.
This work investigates the possibility of utilizing the µp-8085 and its application to concrete crack depth evaluation. For the purpose of the nondestructive testing, ultrasonic pulses are of importance in assessing the quality of concrete as well as flaw detection and measurement. This will be useful in repairing concrete columns.  相似文献   
2.
OBJECTIVE: To study the effects of estrogen on transendothelial paracellular permeability in women. METHODS: Human umbilical vein endothelial cells (HUVEC) obtained from women were grown on filters. The paracellular permeability characteristics were determined in terms of changes in the permeability to the polar acid pyranine (Ppyr) and as changes in the transendothelial electrical resistance (RTE). Tight junctional resistance characteristics were assayed by lowering luminal NaCl and measuring the dilution potential, and were expressed as the ratio of monoion mobility uCl/uNa (cation selectivity). RESULTS: Low extracellular calcium and hyperosmolarity increased Ppyr and decreased RTE. The former but not the latter condition abolished the endothelium-specific cation selectivity. Treatment with 10 nM of estradiol-17 beta had no effect on RTE, but it increased the cation selectivity. The effect of estradiol required 1-6 hours' incubation with the hormone; it was dose dependent and saturable, with a median effective concentration of estradiol of 1 nM. Diethylstilbestrol, but not estriol, could mimic the effect of estradiol, and the estrogen receptor antagonist ICI-182, 780 blocked it. CONCLUSION: Cultured HUVEC cells form patent tight junctions. Estrogens increase the cation selectivity across HUVEC cultures. The effect of estrogen may be mediated by an estrogen receptor. These effects may be important for vasculoprotection in cases of sudden changes in ions levels across the capillary wall, such as ischemia or reperfusion.  相似文献   
3.
Several studies have addressed the possible importance of anti-epithelial cell antibodies in kidney transplantation using the A549 cell line as an in vitro model. In this paper we report our results using for the first time an enzyme-linked immunosorbent assay (ELISA) to detect the anti-A549 cell antibodies. Sera from 129 kidney transplant patients were tested for IgM anti-epithelial cell antibodies directed against the A549 cell line prior to transplantation; only three sera were positive (2.3%). 101 of these patients were then followed-up post-transplantation; sera were collected routinely at 2, 6 and 12 weeks and at the time of rejection episodes. All samples were also tested for cytomegalovirus (CMV) IgM antibodies. Sixteen patients developed anti-A549 IgM antibodies, and there was no correlation with acute graft rejection. Anti-epithelial antibodies showed no binding to sections of normal kidney or biopsies of rejected kidneys. Eleven patients were positive for anti-CMV IgM antibodies. In nine cases both IgM anti-A549 and IgM anti-CMV antibodies were found, which was a highly significant association (p < 0.001). Analysis of A549 cellular proteins by immunoblotting gave evidence for the presence of CMV polypeptides in the cell lysate. Electron-microscopic examination of A549 cell preparations revealed intracellular particles which were compatible in size with CMV. Polymerase chain reaction analysis confirmed the presence of a specific CMV DNA sequence in A549 cells of several batches from different sources. Our data strongly suggest that the A549 cell line used in several published reports is infected with CMV and that in the majority of cases the anti-A549 'anti-epithelial' antibodies found in renal transplant patients are anti-CMV antibodies.  相似文献   
4.
A simple circuit that gives a linear relation between input DC control voltage and an average load voltage is described. This circuit depends on a simple vector difference circuit based on inverse sine evaluation. The load voltage is found to be independent of the supply line voltage and of frequency fluctuations.  相似文献   
5.
The measurements of r.m.s. value of alternating voltage may be made by using sampling and digital integration techniques. Although considerably more complex than analogue methods, the sampling r.m.s. meter has substantial advantages in many respects. The paper discusses the principles on which the meter is based with its error analysis.  相似文献   
6.
In this study microwave-assisted anionic ring opening polymerization (ROP) of alkylene oxides is reported. Low molar mass polymers of propylene oxide (PO), butylene oxide (BO) and hexylene oxide (HO) are synthesized by anionic ring opening using various monohydric alcohols as initiators. The monohydric alcohols and lower molar masses allowed for monitoring of different types of possible unwanted by-products and their sources. Liquid chromatography at critical conditions (LCCC) and liquid adsorption chromatography (LAC) are used to determine the presence of oligomers other than targeted. Finally, MALDI-TOF MS of the products have clearly shown the trends and extents of different types of side reactions that are possible in anionic ring opening of alkylene oxides. Propylene oxide is most vulnerable to chain transfer reactions compared to higher alkylene oxide.  相似文献   
7.
The objective of this study was to investigate the requirement for calmodulin in the cell division of the early human preimplantation embryo. Experiments using three agents capable of inhibiting calmodulin activity, N-(6-aminohexyl)-5-chloro-1-naphthalenesulphonamide (W7), W7 linked to agarose beads (W7-agarose) and calmodulin antibody, showed that W7 and calmodulin antibody arrested division of embryos in a dose-dependent manner. As W7 is able to penetrate the zona pellucida and enter the cells, calmodulin antibody can traverse the zona but not enter the cells and W7-agarose cannot traverse the zona, we have deduced that the calmodulin which appears relevant to embryo division may be both intracellular and intrazonal but not extrazonal. We conclude that calmodulin is specifically required for cell division in the early human preimplantation embryo and that the concentration of calmodulin surrounding the embryo within the zona is particularly important to embryo development.  相似文献   
8.
Mucocele-like tumor and invasive mucinous carcinoma of the breast may represent the two ends of the pathological spectrum of mucinous lesions of the breast, respectively. Little data exists on mucinous lesions that may be considered intermediate between mucocele-like tumor and invasive mucinous carcinoma. We studied 23 consecutive cases of invasive mucinous carcinoma of the breast and observed the following associated intermediate mucinous lesions: mucin-filled ducts (MFD) with unremarkable epithelium in 15 cases (65%), MFD with typical ductal hyperplasia in 9 cases (39%), MFD with atypical ductal hyperplasia in 5 cases (22%), and MFD with intraductal carcinoma in 13 cases (57%; micropapillary or cribriform types). Eighteen cases (78%) contained MFD with one of these four lesions and five cases (22%) contained all four lesions. Twenty-three consecutive cases of infiltrating ductal carcinoma-not otherwise specified (IDC-NOS), 21 cases of intraductal carcinoma, and 50 consecutive cases of surgically-excised breast tissue with fibrocystic change (FC), were similarly reviewed. Only one case (4%) of IDC-NOS, 1 case of intraductal carcinoma, and two cases (4%) of FC, contained small foci of MFD with intraductal carcinoma, intraductal carcinoma, and unremarkable epithelium, respectively. Our findings suggest the presence of a spectrum of mucinous lesions of the breast which represents a pathological continuum.  相似文献   
9.
Brain weights and DNA, RNA, and total protein concentrations were determined on 31-day-old fetuses whose growth had been accelerated incidental to estrogen deficiency following maternal oophorectomy. Compared to controls, there were no differences in the DNA, RNA, or total protein concentrations, although the mean brain weight was increased. The higher mean brain weight in the growth accelerated fetuses was related to the increased mean fetal weight, and did not represent an independent response to the estrogen deficiency. A comparison of the influence of fetal weight versus gestational age on the weight of the fetal brain shows that gestational age exerts an effect apart from that of fetal weight.  相似文献   
10.
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