Search results for "Oxide"
showing 10 items of 6424 documents
Benson group additivity values of phosphines and phosphine oxides : Fast and accurate computational thermochemistry of organophosphorus species
2019
Composite quantum chemical methods W1X-1 and CBS-QB3 are used to calculate the gas phase standard enthalpy of formation, entropy and heat capacity of 38 phosphines and phosphine oxides for which reliable experimental thermochemical information is limited or simply nonexistent. For alkyl phosphines and phosphine oxides, the W1X-1 and CBS-QB3 results are mutually consistent and in excellent agreement with available G3X values and empirical data. In the case of aryl-substituted species, different computational methods show more variation, with G3X enthalpies being furthest from experimental values. The calculated thermochemical data are subsequently used to determine Benson group additivity co…
Carbon Dioxide Activation and Reaction Induced by Electron Transfer at an Oxide-Metal Interface
2015
A model system has been created to shuttle electrons through a metal-insulator-metal (MIM) structure to induce the formation of a CO2 anion radical from adsorbed gas-phase carbon dioxide that subsequently reacts to form an oxalate species. The process is completely reversible, and thus allows the elementary steps involved to be studied at the atomic level. The oxalate species at the MIM interface have been identified locally by scanning tunneling microscopy, chemically by IR spectroscopy, and their formation verified by density functional calculations.
DFT Prediction of Enhanced Reducibility of Monoclinic Zirconia upon Rhodium Deposition.
2018
Oxides are an important class of materials and are widely used, for example, as supports in heterogeneous catalysis. In a number of industrial catalytic processes, oxide supports actively participate in chemical transformations by releasing lattice oxygen anions. While this is intuitively understood for reducible oxides, the reducibility of irreducible oxides may be modified via nanoengineering or upon inclusion of foreign species. Our calculations predict that the ability of irreducible monoclinic zirconia to release oxygen improves substantially upon deposition of rhodium. Through a comprehensive screening of Rh/ZrO2 with different size of the rhodium species, we find that a Rh adatom and…
Oxidative Stress and Antioxidant Levels in Patients with Anorexia Nervosa after Oral Re-alimentation: A Systematic Review and Exploratory Meta-analys…
2015
Oxidative stress markers seem to be higher in patients with anorexia nervosa (AN) than healthy controls, but the potentially beneficial effects of weight gain is not known. We calculated random effects standardised mean differences (SMDs) as effect size measures of oxidative stress marker changes after re-alimentation reported in two or more studies, summarising others descriptively. Seven longitudinal studies (n = 104) were included. After a median follow-up period of 8 weeks, AN patients significantly increased their body mass index (15.1 ± 2.1 to 17.1 ± 2.2, p < 0.0001). This weight gain was followed by a significant increase in serum levels of the antioxidant albumin (studies = 6, SM…
Activation of the p38MAPK cascade is associated with upregulation of TNF alpha receptors in the spinal motor neurons of mouse models of familial ALS.
2005
Phosphorylated p38 mitogen-activated protein kinase (p38MAPK), but not activated c-jun-N-terminal kinase (JNK), increases in the motor neurons of transgenic mice overexpressing ALS-linked SOD1 mutants at different stages of the disease. This effect is associated with a selective increase of phosphorylated MKK3-6, MKK4 and ASK1 and a concomitant upregulation of the TNFalpha receptors (TNFR1 and TNFR2), but not IL1beta and Fas receptors. Activation of both p38 MAPK and JNK occurs in the activated microglial cells of SOD1 mutant mice at the advanced stage of the disease; however, this effect is not accompanied by the concomitant activation of the upstream kinases ASK1 and MKK3,4,6, while both …
One-dimensional nanostructures as electrode materials for water electrolysis
2010
Paramagnetic Defects and Thermoluminescence in Irradiated Nanostructured Monoclinic Zirconium Dioxide
2022
The work was carried out under the grant of the Ministry of Education and Science of the Republic of Kazakhstan AP09260057, “Luminescence and radiation resistance of synthesized under different conditions micro- and nanostructured compacts and ceramics based on ZrO2”. The research was partly (A.I.P.) performed at the Center of Excellence of the Institute of Solid State Physics, University of Latvia, supported through European Union Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2, under grant agreement No. 739508, project CAMART2.
Periodontal Behavior Around Teeth Prepared with Finishing Line for Restoration with Fixed Prostheses. A Systematic Review and Meta-Analysis
2020
Background: The objective of this systematic review and meta-analysis was to analyze the periodontal behavior around teeth prepared with horizontal finishing crowns supporting fixed metal-ceramic and zirconia full coverage crowns and fixed partial dentures (FDPs). Materials and methods: An electronic search was conducted to locate relevant clinical trials in four databases: PubMed, Embase, Cochrane, and Scopus. A manual search was made in the reference sections of the articles identified for any additional articles. No restrictions were applied regarding year of publication or language. The following variables were considered in quantitative and qualitative analysis: probing pocket depth (P…
New Evidence of the Enhanced Elimination of a Persistent Drug Used as a Lipid Absorption Inhibitor by Advanced Oxidation with UV-A and Nanosized Cata…
2019
This work demonstrates new evidence of the efficient destruction and mineralization of an emergent organic pollutant using UV-A and titanium nanosized catalysts. The target compound considered in this work is the primary metabolite of a lipid regulator drug, clofibrate, identified in many studies as refractory during conventional wastewater treatment. The photocatalytic performance study was carried out in batch mode at laboratory scale, in aqueous suspension. Kinetic data showed that titanium dioxide P25 Aeroxide® exhibits the highest photocatalytic efficiency compared to the other investigated catalysts. Pollutant degradation and mineralization efficiencies strongly increased when decreas…
Designing P-Chirogenic 1,2-Diphosphinobenzenes at Both P-Centers Using P(III)-Phosphinites
2016
International audience; A new enantiodivergent synthesis of P-chirogenic 1,2-diphosphinobenzenes (DP*B) bearing the chirality on one or both phosphorus centers is reported using aryne chemistry. The principle is based on successive reactions of 1,2-dibromobenzene with sec-phosphide boranes, then DABCO to remove the borane, and finally with chlorophosphines or P(III)-chirogenic phosphinites. The efficiency of this synthesis was demonstrated by the stereoselective preparation of (S,S)-1,2-bis(o-anisylphenylphosphino)benzene. A comparison of DIPAMP and homochiral DP*B ligands in asymmetric Rh- or Pd-catalyzed reactions was reported.