Search results for "reduction"
showing 10 items of 2058 documents
Electrochemical reduction and carboxylation of halobenzophenones
2002
Abstract The electrochemical reduction of a series of halogenated benzophenones XC6H4COC6H4Y (1) was studied in aprotic solvents, in the absence and presence of CO2, by cyclic voltammetry (CV) and controlled-potential electrolysis. The mechanism of electroreduction in dimethylformamide (DMF) has been investigated in some detail. Most of the compounds undergo reductive carbonhalogen bond cleavage in the time window of CV. The radical anions derived from difluorobenzophenones (X=Y=4-F; X=2-F, Y=4-F) as well as from the 3-chloro derivative are quite stable with a cleavage rate constant (kc) of the order of 10−2 s−1 or less. With 4-chloro-, 2-chloro-, 4,4′-dichloro- and 2,4′-dichorobenzophen…
Measurement of white wines resistance against oxidation by Electron Paramagnetic Resonance spectroscopy
2018
International audience; Free radical theory of aging hypothesizes that oxygen-derived radicals are responsible for the storage-related flavor instability in wine. In an optimal situation, a balanced-distribution exists between oxidants and antioxidants among wines intrinsic/extrinsic metabolites. Based on the kinetic study of POBN-1-hydroxyethyl spin adduct (POBN-1-HER) formation in wines initiated via the Fenton reaction, a novel tool based on EPR spin trapping methodology was developed to quantify wines resistance against oxidation. Antioxidant capacities of wines were evaluated according to POBN-1-HER maximum signal intensity (Imax POBN-1-HER) and rate formation (r(POBN-1-HER)) kinetic p…
Changing the size of a cavity via an electron-transfer: synthesis and reduction of 1,5,22,26-tetraoxa-[5,5]-(2,8)-dibenzo[a,e]cylooctatetraenophane
1989
Abstract The synthesis and electron transfer reactions of the title compound, the first macrocycle incorporating two cyclooctatetraene units, are described.
Biomimetic oxidation of pyrene and related aromatic hydrocarbons. Unexpected electron accepting abilities of pyrenequinones
2014
We present a mild catalytic method to oxidize PAHs and, in particular, pyrene. The pyrenediones are much better electron acceptors than benzoquinone in the gas phase and present similar accepting abilities in solution.
Is activated hemocyanin instead of phenoloxidase involved in immune response in woodlice?
2008
In the Common woodlouse Porcellio scaber (Crustacea: Isopoda: Oniscidea), experimental immune challenge did not induce the expression of pro-phenoloxidase that, in most other invertebrates studied thus far, can be activated into phenoloxidase via an activation cascade upon immune challenge. Instead, Porcellio hemocyanin proved to exhibit catecholoxidase activity upon activation. However, none of the activating factors known from other invertebrates other than SDS-treatment resulted in activation of hemocyanin into a functional phenoloxidase in vitro. The distinct characteristics of isopod hemocyanin are reflected by the quaternary structure of the hemocyanin dodecamers that differs from tha…
Confocal microscopy study of the distribution, content and activity of mitochondria during Paracentrotus lividus development
2007
Summary In the present paper we applied confocal microscopy andfluorescence technologies for studying the distribution andthe oxidative activity of sea urchin ( Paracentrotus lividus )mitochondria during development, by in vivo incubating eggsand embryos with cell-permeant MitoTracker probes. Wecalculated, by a mathematical model, the intensity values, the variations of intensity, and the variation index of incorporatedfluorochromes. Data demonstrate that mitochondrial massdoes not change during development, whereas mitochondrialrespirationincreases.Inaddition,startingfrom16blastomeresstage, some regions of the embryo contain organelles moreactive in oxygen consumption. Introduction The con…
Saggezza dei patterns e nuove strategie cooperative
2013
The paper aims to analyze the concept of downward causation and the role that it plays in the theoretical frameworks of biology and cognitive science.
Paradoxical social representations of linky smart meters and privacy paradox
2021
Consumer participation to electricity consumption reduction (ECR) has become a major challenge in a context of Energy Transition. The Linky french Smart Meter, which use contributes to ECR, is confronted to many controversies reflecting the social legitimation at stake which underlies its evaluation. This article proposes to study privacy paradox regarding Linky Smart Meter use, mobilizing the conceptual background of consumer psychological empowerment. In that aim, a social representation analysis was conducted involving 271 respondents. Results highlight, on one hand, a privacy paradox involving 3 out of the 4 dimensions of psychological empowerment, and on another hand, the presence of m…
Systematic Assessment of MODTRAN Emulators for Atmospheric Correction
2021
Atmospheric radiative transfer models (RTMs) simulate the light propagation in the Earth's atmosphere. With the evolution of RTMs, their increase in complexity makes them impractical in routine processing such as atmospheric correction. To overcome their computational burden, standard practice is to interpolate a multidimensional lookup table (LUT) of prestored simulations. However, accurate interpolation relies on large LUTs, which still implies large computation times for their generation and interpolation. In recent years, emulation has been proposed as an alternative to LUT interpolation. Emulation approximates the RTM outputs by a statistical regression model trained with a low number …
Metformin induces lipid changes on sphingolipid species and oxidized lipids in polycystic ovary syndrome women.
2019
Metformin is one of the treatments used for pcoS pathology decreasing body weight, plasma androgen, FSH and glucose levels. Unfortunately, there is little known about metformin’s effects on lipid metabolism, a crucial process in pcoS pathology. We have employed a lipidomic approach to explore alterations in the plasma lipid profile of patients with PCOS following metformin treatment. The aim is to offer new insights about the effect of metformin in PCOS patients. Plasma samples were obtained from 27 subjects prior to and following 12 weeks of metformin treatment. A detailed biochemical characterization and lipidomic profile was performed. Metformin reduces BMI, HOMA-IR, fSH and androstenedi…