Search results for "OXIDE"
showing 10 items of 6424 documents
The role of yttrium and titanium during the development of ODS ferritic steels obtained through the STARS route: TEM and XAS study
2018
Abstract Oxide Dispersion Strengthened Ferritic Steels (ODS FS) are candidate materials for structural components in future fusion reactors. Their high strength and creep resistance at elevated temperatures and their good resistance to neutron radiation damage is obtained through extremely fine microstructures containing a high density of nanometric precipitates, generally yttrium and titanium oxides. This work shows transmission electron microscopy (TEM) and extended X-ray absorption fine structure (EXAFS) characterization of Fe-14Cr-2W-0.3Ti-0.24Y ODS FS obtained by the STARS route (Surface Treatment of gas Atomized powder followed by Reactive Synthesis), an alternative method to obtain O…
In vitro antibacterial activity of different pulp capping materials
2015
Background: Direct pulp capping involves the application of a dental material to seal communications between the exposed pulp and the oral cavity (mechanical and carious pulp exposures) in an attempt to act as a barrier, protect the dental pulp complex and preserve its vitality. The aim of this study was to evaluate and compare, by the agar disc diffusion test, the antimicrobial activity of six different pulp-capping materials: Dycal (Dentsply), Calcicur (Voco), Calcimol LC (Voco), TheraCal LC (Bisco), MTA Angelus (Angelus), Biodentine (Septodont). Material and Methods: Streptococcus salivarius , Streptococcus sanguis and Streptococcus mutans strains were selected to evaluate the antimicrob…
Oxide/water interfaces: how the surface chemistry modifies interfacial water properties
2012
The organization of water at the interface with silica and alumina oxides is analysed using density functional theory-based molecular dynamics simulation (DFT-MD). The interfacial hydrogen bonding is investigated in detail and related to the chemistry of the oxide surfaces by computing the surface charge density and acidity. We find that water molecules hydrogen-bonded to the surface have different orientations depending on the strength of the hydrogen bonds and use this observation to explain the features in the surface vibrational spectra measured by sum frequency generation spectroscopy. In particular, 'ice-like' and 'liquid-like' features in these spectra are interpreted as the result o…
Coordinate mutation and transformation of mouse fibroblasts: induction by nitroquinoline oxide and modulation by caffeine
1981
Mutation and malignant transformation were followed in the same cells. Mouse fibroblasts (C3H 10T 1/2) were mutated and transformed by 4-nitroquinoline-1-oxide with similar, approximately linear dose-responses. The presence of caffeine immediately after exposure to 4-nitroquinoline-1-oxide potently inhibited mutation and transformation at high but not at low doses of 4-nitroquinoline-1-oxide. Whilst the coordinate induction of mutation and transformation could be explained by both a common target (DNA) or a common reactive species hitting several targets, the identical modulation by a DNA repair inhibitor of both end points suggests fundamental similarities in the nature of the lesions lead…
HSP90 and eNOS partially co-localize and change cellular localization in relation to different ECM components in 2D and 3D cultures of adult rat card…
2007
Background information. Cultivation techniques promoting three-dimensional organization of mammalian cells are of increasing interest, since they confer key functionalities of the native ECM (extracellular matrix) with a power for regenerative medicine applications. Since ECM compliance influences a number of cell functions, Matrigel-based gels have become attractive tools, because of the ease with which their mechanical properties can be controlled. In the present study, we took advantage of the chemical and mechanical tunability of commonly used cell culture substrates, and co-cultures to evaluate, on both two- and three-dimensional cultivated adult rat cardiomyocytes, the impact of ECM c…
Effects of Long-Term Nitroglycerin Treatment on Endothelial Nitric Oxide Synthase (NOS III) Gene Expression, NOS III–Mediated Superoxide Production, …
2000
Abstract —Long-term nitroglycerin (NTG) treatment has been shown to be associated with cross-tolerance to endothelium-dependent vasodilators. It may involve increased production of reactive oxygen species (such as superoxide, O 2 ·− ) that rapidly inactivate the nitric oxide (NO) released from the endothelial cells. It remains to be elucidated, however, whether long-term treatment with NTG alters the activity and expression of the endothelial NO synthase (NOS III) and whether this enzyme can contribute to O 2 ·− formation. We studied the influence of long-term NTG treatment on the expression of NOS III as assessed by RNase protection assay and Western blot. Tolerance was measured ex vivo i…
DNA binding, nuclease activity, DNA photocleavage and cytotoxic properties of Cu(II) complexes of N-substituted sulfonamides.
2013
Abstract Ternary copper(II) complexes [Cu(NST)2(phen)] (1) and [Cu(NST)2(NH3)2]·H2O (2) [HNST = N-(4,5-dimethylthiazol-2-yl)naphthalene-1-sulfonamide] were prepared and characterized by physico-chemical techniques. Both 1 and 2 were structurally characterized by X-ray crystallography. The crystal structures show the presence of a distorted square planar CuN4 geometry in which the deprotonated sulfonamide, acting as monodentate ligand, binds to the metal ion through the thiazole N atom. Both complexes present intermolecular π–π stacking interactions between phenanthroline rings (compound 1) and between naphthalene rings (compound 2). The interaction of the complexes with CT DNA was studied b…
New Features in the dynamics of a ferroin-catalyzed Belousov-Zhabotinsky reaction induced by a zwitterionic surfactant
2008
Abstract Interactions between reaction–diffusion systems and aggregated host environments are a subject of widespread interest. In this work, the behavior of the Belousov–Zhabotinsky reaction was investigated in a micellar environment formed by the zwitterionic surfactant N-tetradecyl-N,N-dimethylamine oxide (C14DMAO). The appearance of an induction period with a threshold-like dependence upon the surfactant concentration, was detected at [C14DMAO] = 5.0 × 10−3 mol dm−3. These new features were explained in terms of the segregation ability typical of the amphiphilic self-assembling systems. Numerical simulations were also performed to confirm the proposed mechanism.
Hyperbranched PEG by Random Copolymerization of Ethylene Oxide and Glycidol
2010
The synthesis of hyperbranched poly(ethylene glycol) (hbPEG) in one step was realized by random copolymerization of ethylene oxide and glycidol, leading to a biocompatible, amorphous material with multiple hydroxyl functionalities. A series of copolymers with moderate polydispersity ($\overline {M} _{{\rm w}} /\overline {M} _{{\rm n}} $ < 1.8) was obtained with varying glycidol content (3-40 mol-%) and molecular weights up to 49 800 g mol(-1) . The randomly branched structure of the copolymers was confirmed by (1) H and (13) C NMR spectroscopy and thermal analysis (differential scanning calorimetry). MTS assay demonstrated low cell toxicity of the hyperbranched PEG, comparable to the highly…
Multiphoton Absorption of Myoglobin Nitric-Oxide complex: Relaxation by D-NEMD of a Stationary State
2012
ABSTRACT: The photodissociation and geminate recombination of nitric oxide in myoglobin, under continuous illumination, is modeled computationally. The relaxation of the photon energy into the protein matrix is also considered in a single simulation scheme that mimics a complete experimental setup. The dynamic approach to non-equilibrium molecular dynamics is used, starting from a steady state, to compute its relaxation to equilibrium. Simulations are conducted for the native form of sperm whale myoglobin and for two other mutants, V68W and L29F, illustrating a fair diversity of spatial and temporal geminate recombination processes. Energy flow to the heme and immediate protein environment …