Search results for "reduction"
showing 10 items of 2058 documents
A nuclear glutathione cycle within the cell cycle
2010
The complex antioxidant network of plant and animal cells has the thiol tripeptide GSH at its centre to buffer ROS (reactive oxygen species) and facilitate cellular redox signalling which controls growth, development and defence. GSH is found in nearly every compartment of the cell, including the nucleus. Transport between the different intracellular compartments is pivotal to the regulation of cell proliferation. GSH co-localizes with nuclear DNA at the early stages of proliferation in plant and animal cells. Moreover, GSH recruitment and sequestration in the nucleus during the G1- and S-phases of the cell cycle has a profound impact on cellular redox homoeostasis and on gene expression. F…
Changes in carnitine octanoyltransferase activity induce alteration in fatty acid metabolism
2011
The peroxisomal beta oxidation of very long chain fatty acids (VLCFA) leads to the formation of medium chain acyl-CoAs such as octanoyl-CoA. Today, it seems clear that the exit of shortened fatty acids produced by the peroxisomal beta oxidation requires their conversion into acyl-carnitine and the presence of the carnitine octanoyltransferase (CROT). Here, we describe the consequences of an overexpression and a knock down of the CROT gene in terms of mitochondrial and peroxisomal fatty acids metabolism in a model of hepatic cells. Our experiments showed that an increase in CROT activity induced a decrease in MCFA and VLCFA levels in the cell. These changes are accompanied by an increase in …
Improved synthesis and in vitro evaluation of the cytotoxic profile of oxysterols oxidized at C4 (4α- and 4β-hydroxycholesterol) and C7 (7-ketocholes…
2013
Whereas the biological activities of oxysterols oxidized at C7 (7-ketocholesterol (7KC), 7β-hydroxycholesterol (7β-OHC), 7α-hydroxycholesterol (7α-OHC)) are well documented, those of oxysterols oxidized at C4 (4β-hydroxycholesterol (4β-OHC), 4α-hydroxycholesterol (4α-OHC)) are not well known, especially on the cells of the central nervous system. Therefore, an improved methodology has been validated for 4β-OHC and 4α-OHC synthesis, and the effects on cell viability and cell growth of these molecules were studied on immortalized, tumoral and normal brain cells (158N, C6 and SK-N-BE cells, and mixed primary cultures of astrocytes and oligodendrocytes). Whereas inhibition of cell growth with 7…
Relationship between structure and CO oxidation activity of ceria supported gold catalysts
2005
Gold catalysts supported on cerium oxide were prepared by solvated metal atom dispersion (SMAD), by deposition-precipitation (DP), and by coprecipitation (CP) methods and were characterized by X-ray diffraction (XRD), temperature programmed reduction (TPR), and X-ray photoelectron spectroscopy (XPS). The catalytic activity was tested in the CO oxidation reaction. The structural and surface analyses evidenced the presence of a modified ceria phase in the case of the DP sample and the presence of pure ceria and gold metal crystallites in the case of the SMAD and CP samples. The DP sample, after a mild treatment in air at 393 K, exhibited only ionic gold, and it was very active below 273 K. By…
Pricing intraday dynamics across EUAS and CERS markets
2011
The relative contribution of European Union Allowances (EUAs) and Certified Emission Reductions (CERs) to the price discovery of their common true value has been empirically studied using daily data with inconclusive results. In this paper, we study the short-run and long-run price dynamics between EUAs and CERs future contracts using intraday data. We report a bidirectional feedback causality relationship both in the short-run and in the long-run, with the EUA's market being the leader.
Serological evidence for protection by human papillomavirus (HPV) type 6 infection against HPV type 16 cervical carcinogenesis
1999
Human papillomavirus (HPV) exists as more than 100 genotypes. It is not well-established whether the different HPV types interfere with infection or pathogenesis by each other. Possible interactions in cervical carcinogenesis between infection with the most common HPV types (6, 11, 16, 18 and 33) were studied in a seroepidemiological case- control study of 218 women with primary untreated cervical cancer and 219 healthy age-matched control women. As previously shown, HPV-16 seropositivity was associated with cervical cancer risk [odds ratio (OR), 2·39], but HPV-16 was not associated with cervical cancer risk among HPV-6 seropositive women (OR, 1·0). The relative excess risk due to interacti…
Efficient and rapid transformation of high silica CHA zeolite from FAU zeolite in the absence of water
2017
High silica CHA zeolite plays an important role in selective catalytic reduction of NOx with NH3 (NH3-SCR), but its synthesis is not highly efficient due to the use of a relatively high-cost structural directing agent (SDA) N,N,N-trimethyl-adamantammonium hydroxide (TMAdaOH) and relatively long crystallization time under hydrothermal conditions. Herein, we report an efficient and rapid synthesis of a high silica CHA zeolite possessing good crystallinity and uniform crystals (CHA-ST). The method includes interzeolite transformation of high silica FAU zeolite in the absence of water but the presence of zeolite seeds and a bromide form of the SDA. The absence of water in the synthesis signific…
Diffusion of Oxygen through Cork Stopper: Is It a Knudsen or a Fickian Mechanism?
2014
International audience; The aim of this work is to identify which law governs oxygen transfer through cork: Knudsen or Fickian mechanism. This is important to better understand wine oxidation during post-bottling aging. Oxygen transfer through cork wafers is measured at 298 K using a manometric permeation technique. Depending on the mechanism, we can extract the transport coefficients. Increasing the initial pressure of oxygen from 50 to 800 hPa leads to a change in the values of the transport coefficients. This implies that oxygen transport through cork does not obey the Knudsen law. From these results, we conclude that the limiting step of oxygen transport through cork occurs in the cell …
From Screening to Scale-Up: The DoE-Based Optimization of Electrochemical Reduction of l-Cystine at Metal Cathodes
2021
Design of experiment (DoE) is a powerful statistical tool in establishing improved chemical processes. An optimization and scale-up of the electrochemical reduction of l-cystine to l-cysteine is pr...
Dating archeological lead artifacts from measurement of the corrosion content using the voltammetry of microparticles.
2011
A methodology for dating archeological lead artifacts based on the voltammetry of microparticles is described. This methodology is based on the comparison of the height of speci¿c voltammetric features from PbO2 and PbO corrosion products formed under long-term alteration conditions. Calibration of the method was performed with the help of a series of well-documented lead pieces from the funds of di¿erent museums of the Comunitat Valenciana (Spain) covering from the ¿fth century B.C. to present day. The variation of peak currents with the time of corrosion can be¿tted to the same potential rate law as that found by Reich (R = 0.070 ( 0.005), using measurements on the Meissner fraction in th…