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Helga Schneider Hans Ulrich Borgstedt Günther Frees 《Journal of Nuclear Materials》1975,56(3):336-340
We have measured the carbon-concentration profiles in the surface zones of specimens of stabilized austenitic steels after exposure to liquid sodium of 700°C in a sodium circuit. Under the conditions of the tests the specimens were carburized. However, the carbon content of the ferritic corrosion layers decreased to values the initial values. They corresponded to the carbon activity of the sodium. 相似文献
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G. Prange und Helga Walther 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1956,104(4):261-266
Zusammenfassung Es wird eine Schnellmethode zur Coffeinbestimmung in Kaffeeaufgüssen bekanntgegeben, die auf der jodometrischen Bestimmung des Coffeinperjodid-Niederschlags beruht. Die Bestimmung, die sich in höchstens 30 min ausführen läßt, besitzt die gleiche Genauigkeit wie die bisherigen Verfahren. 相似文献
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Evaluation of corrosion and deposition phenomena of selected components of a sodium loop The test vessels and heat exchangers of a sodium high temperature loop, which have been exposed to the flowing sodium up to 973 K and flow velocities up to 5 m/s, were examined in respect to long term corrosion effects as well as to deposition effects as well as to deposition effects. In addition to morphologic and metallographic techniques mainly chemical-analytical methods were applied to estimate concentration gradients. The stabilized austenitic steel X 8 CrNiMoNb 16 13 fulfills the demands of high-temperature application in sodium. 相似文献
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Frouke Vermeulen Helga D'Havé Nico W. Van den Brink Lieven Bervoets 《The Science of the total environment》2009,407(5):1775-1783
Hair has been proven to be suitable for non-destructive and non-invasive exposure assessments in human and mammal populations. A previous study with European hedgehog (Erinaceus europaeus) showed that, for some metals, hair and spine metal concentrations were positively correlated to levels in liver, kidney and muscle. Although blood has been studied in a wide variety of species, the relationship between hair and blood metal concentrations has yet to be quantified in many mammalian species. Tissue concentrations from hedgehogs residing in a park with known metal pollution were compared with those from a reference park and correlations between contaminant levels in hair and blood, and spines and blood were studied. Moreover, the relative distribution of arsenic and metals in hair, spines and blood was determined. Elevated concentrations were found in hedgehogs residing in the polluted site for As (8.2 μg/g, 6.3 μg/g, 3.6 μg/ml), Cd (0.48 μg/g, 0.17 μg/g, 0.02 μg/ml) and Pb (7.6 μg/g, 7.3 μg/g, 54 μg/ml), in hair, spines and blood respectively. Positive correlations were identified for exposure levels between hair and blood as well as between spines and blood for three elements (As, Cd, and Pb), whereas a negative correlation was found between Cr concentrations in spines and blood. In conclusion, hair and spines can be used to monitor blood concentrations of some metals, although more data are needed on uptake from the food chain and on the incorporation dynamics of these contaminants. 相似文献
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Helga Simon-Molas Xavier Vallv-Martínez Irene Caldera-Quevedo Pere Fontova Claudia Arnedo-Pac Anna Vidal-Alabr Esther Castao urea Navarro-Sabat Núria Lloberas Ramon Bartrons Anna Manzano 《International journal of molecular sciences》2021,22(14)
The glycolytic modulator TP53-Inducible Glycolysis and Apoptosis Regulator (TIGAR) is overexpressed in several types of cancer and has a role in metabolic rewiring during tumor development. However, little is known about the role of this enzyme in proliferative tissues under physiological conditions. In the current work, we analysed the role of TIGAR in primary human lymphocytes stimulated with the mitotic agent Concanavalin A (ConA). We found that TIGAR expression was induced in stimulated lymphocytes through the PI3K/AKT pathway, since Akti-1/2 and LY294002 inhibitors prevented the upregulation of TIGAR in response to ConA. In addition, suppression of TIGAR expression by siRNA decreased the levels of the proliferative marker PCNA and increased cellular ROS levels. In this model, TIGAR was found to support the activity of glucose 6-phosphate dehydrogenase (G6PDH), the first enzyme of the pentose phosphate pathway (PPP), since the inhibition of TIGAR reduced G6PDH activity and increased autophagy. In conclusion, we demonstrate here that TIGAR is upregulated in stimulated human lymphocytes through the PI3K/AKT signaling pathway, which contributes to the redirection of the carbon flux to the PPP. 相似文献