Search results for "Catalysis"

Promising Strategies for Preserving Adult Endothelium Health and Reversing Its Dysfunction: From Liquid Biopsy to New Omics Technologies and Noninvas…

2022

The endothelium has multiple functions, ranging from maintaining vascular homeostasis and providing nutrition and oxygen to tissues to evocating inflammation under adverse conditions and determining endothelial barrier disruption, resulting in dysfunction. Endothelial dysfunction represents a common condition associated with the pathogenesis of all diseases of the cardiovascular system, as well as of diseases of all of the other systems of the human body, including sepsis, acute respiratory distress syndrome, and COVID-19 respiratory distress. Such evidence is leading to the identification of potential biomarkers and therapeutic targets for preserving, reverting, or restoring endothelium in…

Impact of Single Nucleotide Polymorphisms (SNPs) on Immunosuppressive Therapy in Lung Transplantation.

2015

Lung transplant patients present important variability in immunosuppressant blood concentrations during the first months after transplantation. Pharmacogenetics could explain part of this interindividual variability. We evaluated SNPs in genes that have previously shown correlations in other kinds of solid organ transplantation, namely ABCB1 and CYP3A5 genes with tacrolimus (Tac) and ABCC2, UGT1A9 and SLCO1B1 genes with mycophenolic acid (MPA), during the first six months after lung transplantation (51 patients). The genotype was correlated to the trough blood drug concentrations corrected for dose and body weight (C0/Dc). The ABCB1 variant in rs1045642 was associated with significantly hig…

Enhanced Role of Transition Metal Ion Catalysis During In-Cloud Oxidation of SO2

2013

Global sulfate production plays a key role in aerosol radiative forcing; more than half of this production occurs in clouds. We found that sulfur dioxide oxidation catalyzed by natural transition metal ions is the dominant in-cloud oxidation pathway. The pathway was observed to occur primarily on coarse mineral dust, so the sulfate produced will have a short lifetime and little direct or indirect climatic effect. Taking this into account will lead to large changes in estimates of the magnitude and spatial distribution of aerosol forcing. Therefore, this oxidation pathway-which is currently included in only one of the 12 major global climate models-will have a significant impact on assessmen…

Electrocatalytic properties of ferrooctacarboxyphthalocyanine(II). Electrocatalytic oxygen reduction on the mercury electrode in aqueous solutions

1996

Electrocatalytic reduction of oxygen in aqueous solutions in the presence of ferrooctacarboxyphthalocyanine was investigated. The decay of catalytic properties is attributed to the phthalocyanine aggregation. The mechanism for the four-electron electrocatalytic O2-reduction in neutral and basic media involving FePc(COOH)8 is proposed. It has been found that monomers of phthalocyanine, which are able to form μ-peroxo structures, are the catalytically active forms. The adsorption of various phthalocyanine forms on the mercury electrode plays a very important role in the overall catalytic reaction.

Anti-Aging Effects of GDF11 on Skin

2020

International audience; Human skin is composed of three layers: the epidermis, the dermis, and the hypodermis. The epidermis has four major cell layers made up of keratinocytes in varying stages of progressive differentiation. Skin aging is a multi-factorial process that affects every phase of its biology and function. The expression profiles of inflammation-related genes analyzed in resident immune cells demonstrated that these cells have a strong ability to regenerate adult skin stem cells and to produce endogenous substances such as growth differentiation factor 11 (GDF11). GDF11 appears to be the key to progenitor proliferation and/or differentiation. The preservation of youthful phenot…

Hydroxo Hydrido Complexes of Iron and Cobalt (Sn−Fe−Sn, Sn−Co−Sn): Probing Agostic Sn⋅⋅⋅H−M Interactions in Solution and in the Solid State

2000

Bis(toluene)iron 9 reacts with Lappert's stannylene [Sn[CH(SiMe3)2]2] (4) to form the paramagnetic bis-stannylene complex [[(eta6-toluene)Fe-Sn-[CH(SiMe3)2]2]2] (10). Compound 10 reacts with H2O to form the hydroxo hydrido complex [(eta6-C7H8)(mu-OH)(H)-Fe-[Sn[CH(SiMe3)2]2]2] (12) in high yield; its solid-state structure has been elucidated by X-ray and neutron diffraction analysis. In agreement with the 1H NMR results, 12 contains a hydridic ligand whose exact coordination geometry could be determined by neutron diffraction. The 1H and 119Sn NMR analysis of 12 suggested a multicenter Sn/Sn/H/Fe bonding interaction in solution, based on significantly large values of J(Sn,H,Fe) = 640+/-30 Hz…

Multivariate Metal-Organic Frameworks for the Simultaneous Capture of Organic and Inorganic Contaminants from Water

2019

We report a new water-stable multivariate (MTV) Metal-Organic Framework (MOF) prepared by combining two different oxamide-based metalloligands derived from the natural amino acids L-serine and L-methionine. This unique material features hexagonal channels decorated with two types of flexible and functional 'arms' (-CH2OH and -CH2CH2SCH3) capable to act, synergistically, for the simultaneous and efficient removal of both inorganic (heavy metals like Hg2+, Pb2+ and Tl+) and organic (dyes such as Pyronin Y, Auramine O, Brilliant Green and Methylene Blue) contaminants and, in addition, this MTV-MOF is completely reusable. Single-crystal X-ray diffraction (SCXRD) measurements allowed to solve th…

Selective Introduction of Acid Sites in Different Confined Positions in ZSM-5 and Its Catalytic Implications

2018

Controlling the location of acid sites in zeolites can have a great effect on catalysis. In this work we face the objective of directing the location of Al into the 10R channels of ZSM-5 by taking advantage of the structural preference of B to occupy certain positions at the channel intersections, as suggested by theoretical calculations. The synthesis of B-Al-ZSM-5 zeolites with variable Si/Al and Si/B ratios, followed by B removal in a postsynthesis treatment, produces ZSM-5 samples enriched in Al occupying positions at 10R channels. The location of the acid sites is determined on the basis of the product distribution of 1-hexene cracking as a test reaction. The higher selectivity to prop…

Phase selection of calcium carbonate through the chirality of adsorbed amino acids.

2007

Dual emission of a bis(pyrene)-functionalized, perbenzylated beta-cyclodextrin

2008

A bis(pyrene)-functionalized β-cyclodextrin (1) has been prepared in two steps from perbenzylated β-cyclodextrin. This compound shows dual emission properties, which arise from the pyrenyl chromophores. Upon excitation of 1 at 355 nm, monomer blue fluorescence (386, 407 and 428 nm) is observed in DMSO solution, whereas excimer green fluorescence (477 nm) is seen upon addition of ≥20 vol% water in DMSO. This suggests that modified β-cyclodextrin 1 changes its shape in response to the environment. The sensing properties of 1 towards carboxylic acids and alcohols were investigated in H2O–DMSO (80 : 20 v/v). Monomer fluorescence is restored selectively by medium length normal carboxylic acids, …