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排序方式: 共有806条查询结果,搜索用时 31 毫秒
1.
Gabriela Pitolli Lyra Valdemir Santos Eliria Maria de Jesus Agnolon Pallone Ruth Herta Goldschmidt Aliaga Kiminami Bruno Carlos De Santis João Adriano Rossignolo 《International Journal of Applied Ceramic Technology》2021,18(3):705-715
This work aimed to examine the performance of the hybrid sintering of clay ceramic in a microwave furnace, compared to the sintering process in a conventional furnace. The raw materials were subjected to X-ray fluorescence, loss on ignition (LOI), X-ray diffraction, particle size distribution, real specific mass, and thermogravimetric analyses. The red clay ceramic mass was prepared, extruded, pre-sintered in a conventional furnace at 600°C/60 min, and sintered at temperatures between 700 °C and 1100 °C. The sintering conventional (resistive oven) was carried out for 60 min with a heating rate of 10°C/min. In the microwave furnace, the sintering times were 5, 10, and 15 min, with a heating rate of 50°C/min, with a sintering chamber coated with silicon carbide (susceptor). The sintered specimens were characterized according to linear shrinkage, water absorption, apparent porosity, apparent specific mass, X-ray diffraction, Raman spectroscopy analysis, spectroscopy analysis in the ultraviolet and visible regions, microhardness, and scanning electron microscopy. The results showed that microwave sintering promoted an increase in the microhardness and apparent specific mass, and reduction in water absorption and apparent porosity values, due to greater densification in the microstructure. The best results occurred for specimens sintered at 1100°C. 相似文献
2.
Raffael Ott Xenia Pawlow Andreas Weiß Anna Hofelich Melanie Herbst Nadine Hummel Cornelia Prehn Jerzy Adamski Werner Rmisch-Margl Gabi Kastenmüller Anette-G. Ziegler Sandra Hummel 《International journal of molecular sciences》2020,21(24)
Shared metabolomic patterns at delivery have been suggested to underlie the mother-to-child transmission of adverse metabolic health. This study aimed to investigate whether mothers with gestational diabetes mellitus (GDM) and their offspring show similar metabolomic patterns several years postpartum. Targeted metabolomics (including 137 metabolites) was performed in plasma samples obtained during an oral glucose tolerance test from 48 mothers with GDM and their offspring at a cross-sectional study visit 8 years after delivery. Partial Pearson’s correlations between the area under the curve (AUC) of maternal and offspring metabolites were calculated, yielding so-called Gaussian graphical models. Spearman’s correlations were applied to investigate correlations of body mass index (BMI), Matsuda insulin sensitivity index (ISI-M), dietary intake, and physical activity between generations, and correlations of metabolite AUCs with lifestyle variables. This study revealed that BMI, ISI-M, and the AUC of six metabolites (carnitine, taurine, proline, SM(-OH) C14:1, creatinine, and PC ae C34:3) were significantly correlated between mothers and offspring several years postpartum. Intergenerational metabolite correlations were independent of shared BMI, ISI-M, age, sex, and all other metabolites. Furthermore, creatinine was correlated with physical activity in mothers. This study suggests that there is long-term metabolic programming in the offspring of mothers with GDM and informs us about targets that could be addressed by future intervention studies. 相似文献
3.
Dr. P. S. Dineva-Vladikova Dr. P. Borejko Prof. L. Hadjikov Prof. F. Ziegler 《Acta Mechanica》1996,115(1-4):203-211
Summary The two-dimensional problem of wave propagation in an elastic half-space is studied by the DBIEM (Direct Boundary Integral Equation Method) combined with the finite difference procedure applied to the time variable. The present hybrid formulation employs the fundamental solution depending neither on the frequency nor on the time variable. Time records of surface responses of the half-space are computed and compared with those obtained by the numerical evaluation of exact analytical solutions to this problem. 相似文献
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A Guhlmann K Krauss F Oberdorfer T Siegel PH Scheuber J Müller B Csuk-Gl?nzer S Ziegler H Ostertag D Keppler 《Canadian Metallurgical Quarterly》1995,21(6):1568-1575
N-Acetyl-leukotriene E4 has been identified as an endogenous, biologically less active cysteinyl leukotriene metabolite in rodents and humans. To evaluate the ratio of hepatobiliary to renal elimination of leukotrienes noninvasively by positron emission tomography (PET), we synthesized N-[11C]acetyl-leukotriene E4 by chemical N-acetylation of leukotriene E4. After the intravenous injection of N-[11C]acetyl-leukotriene E4 in normal rats and monkey, uptake by the liver and subsequent excretion into bile were largely responsible for its rapid elimination from blood. In the Cynomolgus monkey, renal excretion of the leukotriene into urine was of additional quantitative importance. Kinetic modeling indicated a mean transit time through the liver of 17 minutes and 34 minutes in rat and monkey, respectively; the corresponding hepatic excretion half-times amounted to 8.5 minutes and 16 minutes. In a mutant rat strain deficient in the hepatobiliary excretion of cysteinyl leukotrienes across the canalicular membrane, the apparent mean liver transit time was 54 minutes, and the hepatic excretion half-time was 29 minutes, indicating prolonged organ storage and metabolism. After transport from the liver back into the circulating blood of omega-oxidized and beta-oxidized metabolites of N-[11C]acetyl-leukotriene E4, renal excretion compensated for the impairment of hepatobiliary elimination in the transport mutant. Metabolite analyses in urine after intravenous injection of N-[3H]acetyl-leukotriene E4 indicated the extensive inactivation of N-acetyl-leukotriene E4 by beta-oxidation from the omega-end in the mutants. A similar shift from hepatobiliary to renal cysteinyl leukotriene elimination was monitored in rats with cholestasis due to bile duct obstruction.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
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Neal E. Craft Katherine S. Epler Therese A. Butler Willie E. May Regina G. Ziegler 《Journal of research of the National Institute of Standards and Technology》1993,98(3):355-359
Aliquots of serum collected in a large case-control study of cervical cancer were stored at −70°C for up to 4 years during implementation of the study. When 500 μL serum aliquots were thawed in preparation for carotenoid and vitamin A assays, volumes were noticeably variable and fell below 500 μL in the majority of the samples. We were concerned about evaporation/sublimation during storage of the samples because loss of water would concentrate the analytes of interest. We evaluated the use of density and sodium ion concentration measurements to confirm its occurrence. We found that serum density was an unreliable indicator of extent of volume loss since the anticipated increases in density due to evaporation were of the same magnitude as inter-individual variation in serum density. In contrast, Na+ concentration is tightly regulated and would rise if water had been lost from the samples. In a representative sample of serum aliquots from the case-control study, 24 of 25 vials contained less than 500 μL of serum. The mean sodium ion concentration (138.1 ± 3.6 mmol/L) was within the normal range for human serum of 136–145 mmol/L, and no correlation was observed between serum volume and Na+ concentration. These results strongly suggest that the observed low volumes were not due to evaporative losses. Instead, the variably low volumes of serum aliquots were probably due to pipetting errors in the initial aliquotting resulting from the use of air-displacement pipettes. 相似文献
9.
To evaluate the diagnostic validity of new assays for bone-specific alkaline phosphatase (BAP), we compared measurements of total alkaline phosphatase (TAP) in serum with results for three different assays of serum BAP in healthy adults (n = 119), patients with chronic nonskeletal disorders (n = 123), and patients with metabolic bone diseases (n = 113). Serum TAP was determined by a standard colorimetric assay, BAP by the methods of lectin precipitation (L-BAP), enzyme immunoassay (E-BAP), and immunoradiometric assay (I-BAP). Impairment of liver function resulted in significant increases of all alkaline phosphatase (AP) measurements, with the smallest changes being exhibited by E-BAP. Compared with the results by TAP, diagnostic sensitivity (i.e., of values exceeding the reference interval) was not improved by BAP, but receiver-operating characteristic (ROC) curve analyses revealed improved discrimination for primary hyperparathyroidism by E-BAP. These results indicate that, in the presence of liver disease, the specificity of AP measurements is improved by measuring BAP. In most other clinical situations, serum TAP appears to provide sufficient clinical information; however, the cross-sectional study design used here allows no statement about the usefulness of BAP in serial measurements. 相似文献
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