Comparative study of the cardioprotective effect of antioxidants emoxipin and hystochrom was conducted in patients with chronic ICD during and after operation for aorto-coronary shunting. Both drugs ...effectively inhibited LPO activation and reduced the reperfusion damage to the myocardium recorded according to the release of MB-PCK into the blood. The new antioxidant hystochrom proved to be more effective. Its prevalent effect is associated with its higher antioxidant activity.
Water-methanol suspensions of size-tuned hollow MoS2 “inorganic fullerenes” (IF) combined with high surface area anatase TiO2 efficiently promote photo catalytic hydrogen evolution reaction (PHER). ...Despite low amount of the MoS2 slabs edges in the structure of closed-shell IF-MoS2 particles and relatively poor dispersion of co-catalyst, the best composite catalysts were nearly 50% as active as Pt/TiO2 benchmark and considerably more active than the reference MoS2–TiO2 catalysts containing highly dispersed MoS2 slabs. Straightforward experimental evidence is given that hydrogen can be formed due to transfer of stored (accumulated) electrons from TiO2 to the IF-MoS2 particles in liquid suspension. Electrochemical flat band potential measurements support the possibility of electrons transfer from TiO2 to IF-MoS2.
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•Transfer of long-live accumulated electrons from TiO2 to MoS2 directly demonstrated.•H2 photo production in methanol-water suspensions near 50% of Pt/TiO2 benchmark.•Fine dispersion of MoS2 on TiO2 and high edges concentration are not important for high activity.
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•Transfer of stored electrons between TiO2 polymorphs in water-methanol suspensions affects photocatalytic properties.•Stored electrons are preferentially transferred from anatase to ...rutile or to brookite.•Simple kinetic model explains H2 production rate vs. relative amounts of polymorphs.
Mechanical mixtures of platinum-loaded and bare anatase, rutile and brookite TiO2 polymorphs were studied in the photocatalytic production of hydrogen (PHER) in methanol-water slurries. Mixtures of TiO2 and Pt/TiO2 materials show non-additivity of catalytic properties as a function of the nature of titania polymorphs involved. Addition of bare rutile or brookite to Pt/anatase leads to a drop of the PHER rate. By contrast, addition of bare anatase improves PHER activity of both Pt/rutile and Pt/brookite. These observations are coherently explained by directional transfer of long-live stored electrons between the particles in suspensions. Hydrogen release in the dark after addition of Pt/TiO2 to pre-illuminated bare TiO2 give evidence that such transfer is fast and have a pronounced directionality. The accumulated electrons are preferentially transferred from anatase to rutile or to brookite. A simple mechanistic framework and a phenomenological kinetic model are proposed that correctly describe the observed variations of PHER rates.
Unsupported MoS2 catalysts were obtained from the decomposition of ammonium tetrathiomolybdate (ATM) at variable temperatures (400-700 degrees C) and under different gas compositions, from pure H2S ...to pure H2. The catalysts were further studied in the non-promoted state or promoted by Ni and Co. Catalytic activity and selectivity were studied in the model reaction of thiophene hydrodesulfurization (HDS). Surface areas, crystalline phase and particle size distributions were determined by Brunauer-Emmet-Teller (BET), X-ray diffraction (XRD) and transmission electron microscopy (TEM), respectively. A comparison of average values calculated from these techniques has enabled the understanding of the morphology of the solids. The catalysts were characterized before and after catalytic tests by X-ray photoelectron spectroscopy (XPS), laser Raman spectroscopy (LRS) and temperature-programmed reduction (TPR). PUBLICATION ABSTRACT
Revisited method of calculation of MoS2 slabs length and stacking in the supported catalysts has been used in a systematic study of the influence of citric acid and treatment conditions on the ...sulfide morphology and HDS activity.
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•Surface weighted averages should be used to calculate length and stacking of MoS2 slabs.•MoS2/Al2O3 morphology and HDS activity studied vs. activation conditions and citric acid addition.•Edge-specific edge HDS activity and TPR of MoS2/Al2O3 are not modified by citric acid.
Molybdenum sulfide MoS2 slabs length L and stacking S obtained from the transmission microscopy (TEM) images are the major characteristics of hydrotreating sulfide catalysts, widely used as morphology descriptors. In this work we demonstrate that the formulae routinely used to estimate mean L and S should be revisited. To obtain physically meaningful values L and S, both should be calculated as surface weighted averages. Moreover, correlation between L and S must be taken into account. Using surface weighted values of mean L and S, MoS2 phase morphology was studied for a series of MoS2/Al2O3 catalysts. The effects of Mo loading, addition of citric acid and sulfidation by H2S/N2 or H2S/H2 mixtures at different temperatures from 350 to 550°C were studied. The catalysts were evaluated in hydrodesulfurization of thiophene (HDS) and studied by temperature programmed reduction (TPR). Thorough statistical treatment of TEM, HDS and TPR data suggests that the intrinsic properties of MoS2 active phase depend primarily on the treatment atmosphere and temperature rather than on the addition of citric acid. If the impregnated catalyst is dried at temperature above 120°C, citric acid allows moderate improvement of MoS2 morphology. However the edge-specific activity of supported sulfide remains unaffected.
Discovering ways to control the magnetic state of media with the lowest possible production of heat and at the fastest possible speeds is important in the study of fundamental magnetism, with clear ...practical potential. In metals, it is possible to switch the magnetization between two stable states (and thus to record magnetic bits) using femtosecond circularly polarized laser pulses. However, the switching mechanisms in these materials are directly related to laser-induced heating close to the Curie temperature. Although several possible routes for achieving all-optical switching in magnetic dielectrics have been discussed, no recording has hitherto been demonstrated. Here we describe ultrafast all-optical photo-magnetic recording in transparent films of the dielectric cobalt-substituted garnet. A single linearly polarized femtosecond laser pulse resonantly pumps specific d-d transitions in the cobalt ions, breaking the degeneracy between metastable magnetic states. By changing the polarization of the laser pulse, we deterministically steer the net magnetization in the garnet, thus writing '0' and '1' magnetic bits at will. This mechanism outperforms existing alternatives in terms of the speed of the write-read magnetic recording event (less than 20 picoseconds) and the unprecedentedly low heat load (less than 6 joules per cubic centimetre).
The paper is concerned with the asymptotic behavior of the correlation functions of the characteristic polynomials of non-Hermitian random matrices with independent entries. It is shown that the ...correlation functions behave like that for the Complex Ginibre Ensemble up to a factor depending only on the fourth absolute moment of the common probability law of the matrix entries.
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