Search results for "NAD"
showing 10 items of 2033 documents
RELATIONSHIP BETWEEN DNA FRAGMENTATION INDEX AND pAKT IN CUMULUS CELLS: NEW MARKERS OF OOCYTE COMPETENCE
2016
The specific LH and FSH polymorphisms could influence the growth of follicles and oocytes.Some studies have shown that certain single nucleotide polymorphisms of FSHR are associated with changes in the ovarian activity, having functional implications in human reproduction. Carriers of polymorphic variant of betaLH show sub-optimal ovarian response to the standard long GnRH-agonist down-regulation protocol, when stimulated with recombinant FSH. No studies have been designed relating the polymorphic variants of FSHR and LHB with the oocyte competence. In previous studies, we demonstrated the correlation between the apoptosis rate and the expression level of some survival pathways molecules, a…
Superoxide Flux in Endothelial Cells via the Chloride Channel-3 Mediates Intracellular Signaling
2007
Reactive oxygen species (ROS) have been implicated in both cell signaling and pathology. A major source of ROS in endothelial cells is NADPH oxidase, which generates superoxide (O2.−) on the extracellular side of the plasma membrane but can result in intracellular signaling. To study possible transmembrane flux of O2.−, pulmonary microvascular endothelial cells were preloaded with the O2.−-sensitive fluorophore hydroethidine (HE). Application of an extracellular bolus of O2.−resulted in rapid and concentration-dependent transient HE oxidation that was followed by a progressive and nonreversible increase in nuclear HE fluorescence. These fluorescence changes were inhibited by superoxide dism…
Educar
2015
El presente artículo describe una experiencia de formación en alternancia en un contexto de educación superior; en concreto, a partir de la iniciativa desarrollada por Florida Universitaria, centro adscrito a la Universidad de Valencia. La formación en alternancia implica alternar el aprendizaje entre períodos desarrollados en el centro educativo y momentos desarrollados en el contexto laboral. El objetivo del presente trabajo es identificar una iniciativa que, de forma empírica, muestre cómo estos periodos impactan en el aprendizaje de competencias de los estudiantes. La metodología que se ha aplicado en la experiencia de formación en alternancia se basa en el aprendizaje basado en problem…
Guided collaboration and computers: Some of its effects on learning outcome
2004
The purpose of the study was to investigate the effects of different treatments on learning outcome, into a collaborative learning context. It was used a factorial design, consisting of two factors, each one with two categories. The first factor was to give students specific roles to play to guide the kinds of interactions and activities that students engage in, versus to allow students to make their own decisions about when and how to use the teacher instructions. The second one was to develop a simple hypertext, versus to write an extended essay. It was found that the factor 'specific roles' favored the learning outcome, whereas the factor 'hypertext development' was not statistically sig…
Energetic coupling between plastids and mitochondria drives CO2 assimilation in diatoms.
2015
International audience; Diatoms are one of the most ecologically successful classes of photosynthetic marine eukaryotes in the contemporary oceans. Over the past 30 million years, they have helped to moderate Earth's climate by absorbing carbon dioxide from the atmosphere, sequestering it via the biological carbon pump and ultimately burying organic carbon in the lithosphere. The proportion of planetary primary production by diatoms in the modern oceans is roughly equivalent to that of terrestrial rainforests. In photosynthesis, the efficient conversion of carbon dioxide into organic matter requires a tight control of the ATP/NADPH ratio which, in other photosynthetic organisms, relies prin…
Influence of Phase Modifiers on the Degradation of Tri-n-octylamine/dodecane Extracting Mixture by an Acidic Solution of Vanadium (V)
2012
The kinetics of degradation of a mixture of tri-n-octylamine (extractant) and various alcoholic phase modifiers in n-dodecane in contact with acidic aqueous sulfate solutions containing vanadium (V) has been investigated. The nature of the modifier influences the kinetics of degradation and an improvement of the resistance against the chemical degradation is obtained when secondary alcohol (2-nonanol) or tertiary alcohols such as 9-octyl-9-heptadecanol are used as phase modifiers instead of 1-tridecanol. For instance, the kinetic constant of degradation is divided by one half when 9-octyl-9-heptadecanol is used as phase modifier instead of 1-tridecanol. On the contrary, the alcohols contain…
Preparation, characterization and catalytic properties of vanadium oxides supported on calcined Mg/Al-hydrotalcite
1995
Abstract Vanadium oxide supported on calcined hydrotalcite has been investigated for the oxidehydrogenation of n-butane in the 500–550°C temperature interval. Hydrotalcite (Mg/Al atomic ratio of 2.77), consisting of a single phase only, has been employed as a support precursor. The vanadium catalysts (0–50, referred as wt.-% V 2 O 5 ) were prepared by impregnation of calcined hydrotalcite (450°C) with ammonium metavanadate (in an aqueous solution) or vanadyl acetylacetonate (in a methanolic solution), and then calcined at 600°C for 4 h. During the impregnation step, the support is transformed into hydrotalcite if aqueous solutions are used. However, it is not modified if methanolic solution…
Microheterogeneous electrocatalytic chiral recognition at monoclinic vanadium-doped zirconias: enantioselective detection of glucose.
2007
Synthetic tetragonal and monoclinic vanadium-doped zirconias (t- and m-VxZr1-xO2, 0.005x0.150) exert an effective catalytic effect toward the electrochemical oxidation of glucose in aqueous alkaline media. The catalytic effect of monoclinic specimens attached to carbon and fluorine-doped tin oxide electrodes exhibits a remarkable enantioselectivity, so that catalytic currents for the oxidation of L-glucose at +0.92 V vs AgCl/Ag are considerably larger than those obtained for the oxidation of D-glucose. This enantioselectivity can be associated with the existence of a noncentrosymmetric coordination of vanadium centers in the monoclinic crystalline form of zirconia. From the electrochemical …
Synthesis of new molybdenum–tungsten, vanadium–tungsten and vanadium–molybdenum–tungsten oxynitrides from freeze-dried precursors
2004
Abstract Interstitial molybdenum–tungsten, vanadium–tungsten and vanadium–molybdenum–tungsten oxynitrides in the solid solution series Mo1−zWz(OxNy) and V1−zWz(OxNy) (z=0, 0.2, 0.4, 0.5, 0.6, 0.8, 1), and V1−u−zMouWz(OxNy) (u, z=0.2, 0.33, 0.4, 0.6; u+z
Thermodynamics of titanium and vanadium reduction in non-aqueous environment calculated at various levels of theory.
2012
Reduction of titanium and vanadium compounds is a process accompanying the activation of coordinative olefin polymerization catalysts. Four density functional theory (DFT) functionals, coupled cluster with single, double, and perturbative triple excitations method CCSD(T) as well as complete active-space second-order perturbation theory method CASPT2 with a complete active-space self-consistent field CASSCF reference wave function were applied to investigate the thermodynamics of titanium and vanadium reduction. The performance of these theoretical methods was assessed and compared with experimental values. The calculations indicate that vanadium(IV) chloride is more easily reduced by trime…