Smooth hydrocarbon films formed on the vacuum chamber walls in tokamaks under the erosion of graphite elements during deuterium plasma discharges are the main accumulators of hydrogen isotopes in ...carbon matrices. Therefore, they can be considered as a promising material for hydrogen storage applications. In the present work, such hydrocarbon CD
x
films (x ∼ 0.5) produced in T-10 tokamak (NRC Kurchatov Institute, Russia) were studied using scanning electron microscopy (SEM), NEXAFS and EXAFS spectroscopies together with thermal desorption (TD) for the films' characterization and estimation of their hydrogen storage capacity. The C 1s X-ray absorption spectra of the CD
x
films were recorded for the first time using the BESSY II storage ring facility (Germany). The obtained NEXAFS spectra were found typical for CK-spectra of sp
3
+ sp
2
hydrocarbon systems with a high H/C ratio. The role of Fe impurities from the tokamak chamber walls was elucidated as a catalytic effect "facilitating" the thermal desorption of hydrogen (deuterium) from CD
x
films. The Fe K-edge spectra allowed to confirm a fractal (self-affined) structure of CD
x
films, with a minimal sp
2
fractal aggregate ∼2-3 nm, and formation of 3D carbon sp
3
+ sp
2
network, accumulated a large number of H-isotopes and C
x
H
y
hydrocarbons. It was found that the H storage and thermal desorption properties of the CD
x
films can be improved by their inherent Fe impurities, capable to reduce the barrier of TD and to increase the H/C storage capacity by several times even at room temperature.
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BFBNIB, GIS, IJS, KISLJ, NUK, PNG, UL, UM, UPUK
To analyze the catalytic properties of heat shield materials of space vehicles, the cluster models of the adsorption of oxygen atoms on aluminum oxide are constructed and the corresponding potential ...energy surface is calculated on the basis of the density functional theory. Quantum-mechanical calculations showed that it is necessary to take into account the relaxation of the surface monolayers. Using this surface in molecular dynamics, calculations made it possible to obtain the probabilities of the heterogeneous recombination of oxygen atoms on the α-Al2O3 surface, which are in good agreement with experimental data. The calculations performed substantially decrease the amount of experimental investigations necessary reliably to describe the heterogeneous catalysis on promising reusable heat shield coatings for analyzing heat transfer during spacecraft entry into the atmosphere.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Background
We aimed to evaluate the graft patency rate following coronary artery bypass grafting (CABG) to the left anterior descending artery (LAD) with proximal myocardial bridging (MB). While MB ...is generally a benign coronary abnormality, ischemia, stunning, and sudden death have been reported. In symptomatic patients with proximal LAD systolic compression of >50%, positive for ischemic noninvasive testing and noneffective optimal medical therapy, coronary intervention could be indicated. Few studies of CABG in myocardial bridging have been reported. The influence of high flow in coronaries with MB on graft patency is cause for concern.
Methods
We retrospectively studied 39 patients operated on for isolated MB of proximal LAD with >50% systolic compression. All patients were severely symptomatic despite optimal medical therapy and positive noninvasive tests for myocardial ischemia. CABG was performed through the midsternotomy with cardiopulmonary bypass and cardioplegia. Patients were divided into two groups: in 20 patients, LAD was bypassed with left internal mammary artery (LIMA) (Group 1) and in 19 patients with saphenous vein graft (SVG) (Group 2). All patients underwent follow‐up coronary angiography.
Results
Demographics and degree of systolic compression of the LAD were similar in both groups. There was no mortality or major morbidity. Freedom from angina was 68% in Group 1 and 94% in Group 2 at 18 months postoperatively (p = 0.58). Twelve LIMA grafts and three SVGs were found occluded (p = 0.002).
Conclusions
LIMA patency in myocardial bridging of the LAD can be low. SVGs should be considered in cases of CABG for myocardial bridging. doi: 10.1111/jocs.12101 (J Card Surg 2013;28:218–221)
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BFBNIB, DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UILJ, UKNU, UL, UM, UPUK
