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排序方式: 共有305条查询结果,搜索用时 312 毫秒
111.
NN Ter-Minasova AG Minasian AF Muradian TO Karapetian ZhL Akopian 《Canadian Metallurgical Quarterly》1976,94(2):55-57
From 1967 to 1974 vaginal and cervical smears of about 46,000 teenage girls and young women up to the age of 25 were examined. Among these were 250 doubtful and positive cases (0,54%). Of the 67 positive ones 46 cases were known to be histologically examined (69%); 8 times an invasive carcinoma and 38 times a carcinoma in situ were found. Women under the age of 25 should therefore be included in routine check-up with cervical and vaginal smears. 相似文献
112.
While using the contemporary mathematical models for activated sludge systems, it is necessary to describe quantitatively the kinetics of microbiological processes and to characterise substrate (wastewater components in the influent) as well as biomass (activated sludge). In this paper, the kinetic parameters of the aerobic biodegradation of organic matter in wastewater containing synthetic surfactants in an activated sludge system were determined and discussed. Also, the composition of the tested wastewater was estimated and expressed as COD fractions. Five synthetic surfactants, three anionic and two nonionic, of different chemical structure were investigated. Each of them was tested separately and dissolved in wastewater to obtain a concentration of 50 mgl(-1), which can be found in some industrial wastewater. The presence of the elevated amount of synthetic surfactants in wastewater decreased the affinity of biomass to substrate. Nevertheless, maximum specific growth rates (micromax) of heterotrophic biomass exposed to wastewater containing surfactants were high but usually lower than micromax estimated for wastewater without surfactant. Surfactants, which contain a benzene ring, were the most likely to deteriorate wastewater treatment processes in the activated sludge systems. 相似文献
113.
Comparison of nutrients degradation in small scale membrane bioreactors fed with synthetic/domestic wastewater 总被引:1,自引:0,他引:1
Two membrane bioreactors were operated with biological phosphorus removal, carbon degradation and denitrification to check how comparable and representative they were compared to full-scale plants. One was fed with synthetic municipal wastewater and was switched from pre- to post-denitrification without carbon dosing. The influent of the second plant was drawn from a separate sewer. This plant worked the whole time with post-denitrification without carbon dosing. The synthetic wastewater was designed to achieve a realistic COD:TN:TP ratio and tested for long time biodegradability. The eliminations were >94% (COD) and >97% (TP) for both plants. This was within the range of commercial plants, as well as the TN elimination for the pre-denitrification of plant I (>75%). The eliminations of TN for post-denitrification were above 80% for both plants despite the high influent concentrations and the missing carbon source for post-DN. A calculation of the nitrification rates gave values similar to those found in literature (1-6 mgN/(gMLVSSh)). A comparison of the denitrification showed expected rates for pre-denitrification (7.5 mgN/(gMLVSSh)) for plant I. The values (on average 1.8 mgN/(gMLVSSh)) for post-denitrification in plant II were higher than endogenous denitrification rates which are commonly reported as 0.2-0.8 mgN/(gMLVSSh). The rates for post-denitrification in plant I were only slightly higher than endogenous ones (0.9 mgN/(gMLVSSh)). 相似文献
114.
Tina Skale Dmitrij Stehl Lena Hohl Matthias Kraume Regine von Klitzing Anja Drews 《化学,工程师,技术》2016,88(11):1827-1832
The use of Pickering emulsions has recently received increased attention in catalyzed multiphase reactions. Here, the ultrafiltration of Pickering emulsions is studied for product separation and to retain the catalyst in the reactor. To find the optimum between a high specific surface area for high reaction rates and a suited drop size distribution for high permeate fluxes, the preparation method of Pickering emulsion was investigated. It was found that the stability of the emulsion during filtration does not only depend on the solid particle content, but also on the drop size distribution. 相似文献
115.
Consumption of foods containing Staphylococcus aureus can cause severe gastro-intestinal illness. Given the fact that over the past decade, Canada has seen increasing rates of methicillin-resistant S. aureus (MRSA) carriage and infection, the objective of this study was to investigate the impact of methicillin-susceptible S. aureus (MSSA) and MRSA on foodborne illness in Alberta, Canada. Between January 2007 and December 2010, there were 693 food samples associated with foodborne investigations submitted to the Alberta Provincial Laboratory for Public Health (ProvLab). These foods were screened for: Bacillus cereus, Clostridium perfringens, S. aureus, Aeromonas spp., Campylobacter spp., Escherichia coli O157:H7, Salmonella, Shigella spp., and Yersinia spp. S. aureus was identified in 10.5% (73/693) of samples, and of these, 59% (43/73) were co-contaminated with at least one other organism on the screening panel. The S. aureus positive samples included 29 meat, 20 prepared foods containing meat, 11 prepared foods not containing meat, 10 dairy, and three produce. Methicillin-resistance was not detected in any isolates tested. These findings indicate that the presence of S. aureus in food associated with foodborne investigations is a cause for concern, and although MRSA was not found, the potential for outbreaks exists, and ongoing surveillance should be sustained. 相似文献
116.
Margarita P. Thompson Gregory W. Auner Andrew R. Drews 《Journal of Electronic Materials》1999,28(10):L17-L19
Epitaxial zinc-blende AlN films were deposited on Si(100) substrates by plasma source molecular beam epitaxy (PSMBE). The lattice parameter of the zinc-blende AlN was determined to be 4.373Å. The epitaxial relationship between film and substrate was (100)AlN‖(100)Si and [011]AlN‖[011]Si. The zinc-blende AlN films were formed using a hollow cathode source with a pulse d.c. power supply in the PSMBE system. The high energy and large density of the Al+ and N+ species emerging from the hollow cathode and the presence of a substrate surface with cubic symmetry are probably the main factors for the formation of the metastable zinc-blende phase of AlN. 相似文献
117.
BACKGROUND: Leptin, a product of the obese (ob) gene, is released from adipocytes. At the same body mass index, women have higher concentrations than men. Thus, during pregnancy, leptin may influence gestational weight gain and retention of a portion of that gain postpartum. OBJECTIVE: We examined the relation between plasma leptin at entry to prenatal care and subsequent changes in weight from entry to prenatal care (at 17 wk gestation, baseline) until 6 mo postpartum. DESIGN: This was an observational study of leptin, gestational weight gain, and postpartum weight retention (at 6 wk and 6 mo postpartum) in 103 low-income pregnant women from Camden, NJ, with a pregravid body mass index (in kg/m2) in the normal range (19.8-26). RESULTS: After potential confounding variables were controlled for, leptin at entry significantly (P < 0.05) predicted weight gain in pregnancy, including measured rate of weight gain (x +/- SEE: 0.25 +/- 0.13 kg x unit log leptin(-1) x wk(-1)), measured rate of third-trimester weight gain (0.37 +/- 0.15 kg x unit log leptin(-1) x wk(-1)), rate of weight gain from recalled pregravid weight (0.23 +/- 0.09 kg x unit log leptin(-1) x wk(-1)), and net rate of gestational weight gain (0.22 +/- 0.09 kg x unit log leptin(-1) x wk(-1)). The leptin concentration at entry also significantly predicted retained weight in the postpartum period (at 6 mo: 7.29 +/- 3.33 kg/unit log leptin at entry) and marginally predicted changes in the sum of skinfold thicknesses (at 6 mo: 14.7 +/- 7.5 mm/unit log leptin at entry). CONCLUSION: These results suggest that a high leptin concentration at entry to prenatal care may predict an increased risk of overweight and obesity in vulnerable women. 相似文献
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