Clinical, angiographic and procedural correlates of quantitative coronary dimensions after directional coronary atherectomy

AbstractTo define the clinical, angiographic and procedural correlates of quantitative coronary dimensions after directional coronary atherectomy, 400 lesions in 378 patients were analyzed with use of qualitative morphologic and quantitative angiographic methods. Successful atherectomy, defined by a <75% residual area stenosis, tissue retrieval and the absence of in-hospital ischemic complications, was performed in 351 lesions (87.7%). After atherectomy, minimal cross-sectional area increased from 1.2 ± 1.1 to 6.6 ± 4.4 mm2(p < 0.001) and percent area stenosis was reduced from 87 ± 10% to 31 ± 42% (p < 0.001).By univariate analysis, device size (p < 0.001) and left circumflex artery lesion location (p = 0.004) were associated with a larger final minimal cross-sectional area. Conversely, restenotic lesion (p = 0.002), lesion length ≥ 10 mm (p = 0.018) and lesion calcification (p = 0.035) were quantitatively associated with a smaller final minimum cross-sectional area. With use of stepwise multivariate analysis to control for the reference area, atherectomy device size (p = 0.003) and left circumflex lesion location (p = 0.007) were independently associated with a larger final minimal cross-sectional area, whereas restenotic lesion (p = 0.010), diffuse proximal disease (p = 0.033), lesion length ≥ 10 mm (p = 0.026) and lesion calcification (p = 0.081) were significantly correlated with a smaller final minimal cross-sectional area. The number of specimens excised, the number of atherectomy passes and atherectomy balloon inflation pressure did not correlate with the final minimal cross-sectional area.Thus, directional atherectomy results in marked improvement of coronary lumen dimensions, at least in part correlated with the presence of certain clinical, angiographic and procedural factors at the time of atherectomy

A simple procedure to quantitatively assess the photoactivity of titanium dioxide films

A simple and inexpensive procedure based on the bleaching of orange II (acid orange 7) solution has been developed in order to quantitatively assess the photocatalytic activity of titanium dioxide thin films. The influence of experimental parameters including, pH and light flux density on the reaction rate has been investigated. The results of this study suggest that at natural pH (7.2) and low dye concentration, the mechanism responsible for the degradation of orange II is mainly photooxidation via the formation of radicals. The procedure was used to compare the photoefficiency of TiO2 films poisoned with variable amounts of sodium. The obtained results are in good agreement with the previously reported effect of sodium on the photoactivity of titanium dioxide thin films. © 2010 Elsevier B.V

Effect of compressive stress inducing a band gap narrowing on the photoinduced activities of sol-gel TiO2 films

TiO2 thin films grown on different kinds of substrates were obtained by sol–gel process. X-ray diffraction revealed that the TiO2 lattice parameter c decreased continuously, indicating a continuous variation in the compressive stress, a negligible compressive stress of the film grown onto Soda-Lime Glass (SLG), medium compressive stress of the film grown onto BoroSilicate Glass (BSG) and large compressive stress of the film deposited onto the Quartz Substrate (QS). UV–Vis absorbance spectra exhibited a red-shift of the absorbance edge of the TiO2 films suggesting a lowering of the band gap, which is a direct consequence of the increase of the compressive stress. X-ray photoelectron spectroscopy revealed that the surface composition of titania films was similar except for sodium-ion concentration. The rate observed during the photo-oxydation of the stearic acid on TiO2/QS was twice as high as that of TiO2/BSG and about 1000 times superior to that of TiO2/SLG. The photoinduced wettability shows an identical dependence of the compressive stress. According to these results, the compressive stress could be used to tune the band gap of the titanium oxide in order to enhance the photoinduced properties

Synthèse de nanotubes d’imogolite photoactifs pour la production d’hydrogène

International audienc

Strategies to Enhance the Efficiency of Gold Catalysts in Base-Free Oxidation of Biobased Compound

International audienc

Supported Gold Catalysts for Base-Free Furfural Oxidation: The State of the Art and Machine-Learning-Enabled Optimization.

International audienceSupported gold nanoparticles have proven to be highly effective catalysts for the base-free oxidation of furfural, a compound derived from biomass. Their small size enables a high surface-area-to-volume ratio, providing abundant active sites for the reaction to take place. These gold nanoparticles serve as catalysts by providing surfaces for furfural molecules to adsorb onto and facilitating electron transfer between the substrate and the oxidizing agent. The role of the support in this reaction has been widely studied, and gold–support interactions have been found to be beneficial. However, the exact mechanism of furfural oxidation under base-free conditions remains an active area of research and is not yet fully understood. In this review, we delve into the essential factors that influence the selectivity of furfural oxidation. We present an optimization process that highlights the significant role of machine learning in identifying the best catalyst for this reaction. The principal objective of this study is to provide a comprehensive review of research conducted over the past five years concerning the catalytic oxidation of furfural under base-free conditions. By conducting tree decision making on experimental data from recent articles, a total of 93 gold-based catalysts are compared. The relative variable importance chart analysis reveals that the support preparation method and the pH of the solution are the most crucial factors determining the yield of furoic acid in this oxidation process

Combining top-down and bottom-up routes for fabrication of mesoporous titania films containing ceria nanoparticles for free radical scavenging

Nanocomposite thin films formed by amorphous mesoporous titania layers loaded with ceria nanoparticles have been obtained by combining bottom-up self-assembly synthesis of titania matrix with top-down hard X-ray lithography of nanocrystalline cerium oxide. At first the titania mesopores have been impregnated with the ceria precursor solution and then exposed to hard X-rays. The X-ray exposure of the films triggers the formation of crystalline cerium oxides within the pores inducing in-situ nanoparticles growing with average size of 4 nm. It has been observed that the type of coordinating agent in the solution plays a primary role in the formation of nanoparticles. Different patterns have been also produced through Deep X-ray Lithography by spatially controlling the nanoparticles growing on the micrometer scale. The radical scavenging role of the nanocomposite films have been tested using the UV photodegradation of rhodamine 6G as benchmark. After impregnation with a rhodamine 6G solution, samples with and without ceria have shown a remarkably different response upon exposure to UV light. The dye photodegradation on the surface of nanocomposite films appears strongly slow down because of the anti-oxidation effect of ceria nanoparticles