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1.
B. Gervais M. Beuve G.H. Olivera M.E. Galassi R.D. Rivarola 《Chemical physics letters》2005,410(4-6):330-334
We present a simulation of liquid water radiolysis by swift carbon ions that explicitly takes into account multiple ionization of water molecules. For high linear energy transfer (LET), this process is not negligible with respect to single ionization. The rearrangement of highly ionized water molecules is consistent with production of atomic oxygen. Multiple ionizations is shown to be responsible for creation of a large amount of radicals and O2 molecules. The simulated yield reproduces very well direct optical measurements for swift ions with comparable LET. Our simulation for is in also agreement with experiment. 相似文献
2.
In oxydehydrogenation of ethylbenzene to styrene catalytic active centers are created by coke formed during the reaction. Formation of active coke can be made evident by product analysis in the first minutes of operation and by analysis of the carbonaceous resisdues by temperature programmed oxidation (TPO) and EPR.
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3.
Michele Arcangelo Quinto Juan Manuel Monti Mario Enrique Alcocer Avila Philippe F. Weck Omar Ariel Fojón Roberto Daniel Rivarola Christophe Champion 《X射线光谱测定》2020,49(1):95-98
The present work focuses on studying the contribution of the Auger electron emission in proton-induced interactions in biological matter. The Monte Carlo track-structure code, TILDA-V, was then used for modeling the protons beams of 10 keV to 100 MeV in biological matter, namely, water vapor and hydrated DNA. The main ionizing processes are described by means of an extensive set of ab initio differential and total cross sections computed within a quantum-mechanical CDW-EIS approximation. 相似文献
4.
Background
Growth hormone (GH) plays an incompletely understood role in the development of the central nervous system (CNS). In this study, we use transgenic mice expressing a growth hormone antagonist (GHA) to explore the role of GH in regulating postnatal brain, spinal cord and body growth into adulthood. The GHA transgene encodes a protein that inhibits the binding of GH to its receptor, specifically antagonizing the trophic effects of endogenous GH. 相似文献5.
Zingaretti L Mariano Correa N Boscatto L Chiacchiera SM Durantini EN Bertolotti SG Rivarola CR Silber JJ 《Journal of colloid and interface science》2005,286(1):245-252
The distribution of different aliphatic and aromatic amines: n-butylamine (n-BA), isobutylamine (i-BA), tert-butylamine (t-BA), piperidine (PIP), N,N-dimethylaniline (DMA) and N-methylaniline (MA) in water/sodium 1,4-bis(2-ethylhexyl)sulfosuccinate(AOT)/n-hexane reverse micelles was investigated by steady-state fluorescence measurements. The partition constants were measured by an indirect method based on the effect that amine partitioning exert on the bimolecular rate of the reaction between a microphase incorporated fluorophore (Ru(bpy)2+(3)) and the quencher, (Fe(CN)3-(6)). For MA, that can act as a quencher of the fluorophore a direct method was used. The results show that primary amines have larger partition constants than the secondary ones. For tertiary amines the distribution constants were practically negligible. Laser flash photolysis experiments confirmed that tertiary amines, both aliphatic and aromatic, are not incorporated to the micellar pseudophase. The effect of the amine structure on the partition constant was analyzed through linear solvation free energy relationships (LSER) using solute parameters and compared with those obtained for alcohols. Hydrogen bond interactions with the AOT polar heads appear to be the main driving force for the distribution of amines between the organic and micellar pseudophases, whereas the size of the alkyl or aromatic group tends to hinder it. 相似文献
6.
Tushar S. Basu Baul Archana Mizar Eleonora Rivarola Michal Hol?apek Ulli Englert 《Journal of organometallic chemistry》2006,691(16):3416-3425
A series of cis-bis{5-[(E)-2-(aryl)-1-diazenyl]quinolinolato}diphenyltin(IV) complexes have been synthesized and characterized by 1H, 13C, 119Sn NMR, ESI-MS, IR and 119mSn Mössbauer spectroscopic techniques in combination with elemental analysis. The structures of a ligand L6H (i.e., 5-[(E)-2-(4-ethoxyphenyl)-1-diazenyl]quinolin-8-ol) and three diphenyltin(IV) complexes, viz., Ph2Sn(L1)2 · (CH3)2CO (1), Ph2Sn(L4)2 (4) and Ph2Sn(L5)2 (5) (L = 5-[(E)-2-(aryl)-1-diazenyl]quinolin-8-ol: aryl = phenyl - (L1H); 4′-methylphenyl - (L4H) and 4′-bromophenyl - (L5H)) were determined by single crystal X-ray diffraction. In general, the complexes were found to adopt a distorted cis-octahedral arrangement around the tin atom. These complexes retain their solid-state structure in non-coordinating solvent as evidenced by 119Sn NMR spectroscopic results. The in vitro cytotoxicity of 1 is reported and compared with Ph2Sn(Ox)2 (Ox = deprotonated quinolin-8-ol) against seven well characterized human tumor cell lines. 相似文献
7.
A Mukherjee M Dasgupta DJ Hinde CR Morton AC Berriman RD Butt JO Newton H Timmers 《Pramana》2001,57(1):195-198
Fusion cross-sections for the 7Li + 12C reaction have been measured at energies above the Coulomb barrier by the direct detection of evaporation residues. The heavy
evaporation residues with energies below 3 MeV could not be separated out from the α-particles in the spectrum and hence their
contribution was estimated using statistical model calculations. The present work indicates that suppression of fusion cross-sections
due to the breakup of 7Li may not be significant for 7Li + 12C reaction at energies around the barrier. 相似文献
8.
M E Milanesio M G Alvarez E I Yslas C D Borsarelli J J Silber V Rivarola E N Durantini 《Photochemistry and photobiology》2001,74(1):14-21
The photodynamic activities of the free-base 5,10,15,20-tetrakis(4-methoxyphenyl)porphyrin (TMP) and their metal complexes with zinc(II) (ZnTMP), copper(II) (CuTMP) and cadmium(II) (CdTMP) have been compared in two systems: reverse micelle of n-heptane/sodium bis(2-ethylhexyl)sulfosuccinate/water bearing photooxidizable substrates and Hep-2 human larynx carcinoma cell line. The quantum yields of singlet molecular oxygen, O2(1 delta g), production (phi delta) of TMP, ZnTMP and CdTMP in tetrahydrofuran, were determined yielding values of 0.65, 0.73 and 0.73, respectively, while O2(1 delta g) formation was not detected for CuTMP. In the reverse micellar system, the amino acid L-tryptophan (Trp) was used as biological substrate to analyze the O2(1 delta g)-mediated photooxidation. The observed rate constants for Trp photooxidation (kobsTrp) were proportional to the sensitizer quantum yield of O2(1 delta g). A value of approximately 2 x 10(7) s-1 M-1 was found for the second-order rate constant of Trp (krTry) in this system. The response of Hep-2 cells to cytotoxicity photoinduced by these agents in a biological medium was studied. The Hep-2 cultures were treated with 1 microM of porphyrin for 24 h at 37 degrees C and the cells exposed to visible light. The cell survival at different light exposure levels was dependent on phi delta. Under these conditions, the cytotoxic effect increases in the order: Cu-TMP < TMP < ZnTMP approximately CdTMP, correlating with the production of O2(1 delta g). A similar behavior was observed in both the chemical and biological media indicating that the O2(1 delta g) mediation appears to be mainly responsible for the cell inactivation. 相似文献
9.
R. Gayet J. Hanssen A. Martinez R. Rivarola 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1991,18(4):345-350
The CDW and CDW-EIS approximations are used to study the resonant double electron capture by He2+ in helium at intermediate and high impact velocities. Calculations of the total cross sections as a function of the impact energy are performed in an Independent Electron Approximation. A very good agreement with recent experimental data for capture into all states of the projectile is found although neither angular nor dynamical electron correlations are included in the calculations. 相似文献
10.
Tushar S. Basu Baul Cheerfulman Masharing Eleonora Rivarola Robert Jirásko Dick de Vos 《Journal of organometallic chemistry》2006,691(5):952-965
Reactions of potassium β-{[(E)-1-(2-hydroxyaryl)alkylidene]amino}propionates (L1HK-L3HK) and potassium β-{[(2Z)-(3-hydroxy-1-methyl-2- butenylidene)]amino}propionate (L4HK) with R3SnCl (R = Ph and nBu) and nBu2SnCl2 yielded complexes of composition Ph3SnL1H (1), Ph3SnL2H (2), Ph3SnL4H (3), nBu3SnL1H (4), and {[nBu2Sn(L2H)]2O}2 (5) and {[nBu2Sn(L3H)]2O}2 (6), respectively. These complexes have been characterized by 1H, 13C, 119Sn NMR, ESI-MS, IR and 119mSn Mössbauer spectroscopic techniques in combination with elemental analyses. The crystal structures of 1, 4, 5 and 6 were determined. In the solid state, compound 1 is a one-dimensional polymer built from SnPh3 moieties bridged by single carboxylate ligands, but two alternating modes of bridging are present along the polymeric chain. Compound 4 is also a one-dimensional polymer built from SnBu3 moieties bridged by the two carboxylate O-atoms of a single ligand, but only one mode of bridging is present. Di-n-butyltin compounds 5 and 6 are centrosymmetric tetranuclear bis(dicarboxylatotetrabutyldistannoxane) complexes containing a planar Sn4O2 core in which two μ3-oxo O-atoms connect an Sn2O2 ring to two exocyclic Sn-atoms. The four carboxylate ligands display two different modes of coordination where both modes involve bridging of two Sn-atoms. The solution structures were predicted by 119Sn NMR spectroscopy. The in vitro cytotoxic activity of compound 5 against WIDR, M19 MEL, A498, IGROV, H226, MCF7 and EVSA-T human tumor cell lines is reported. 相似文献