FAT1 mutations cause a glomerulotubular nephropathy

Steroid-resistant nephrotic syndrome (SRNS) causes 15% of chronic kidney disease (CKD). Here we show that recessive mutations in FAT1 cause a distinct renal disease entity in four families with a combination of SRNS, tubular ectasia, haematuria and facultative neurological involvement. Loss of FAT1 results in decreased cell adhesion and migration in fibroblasts and podocytes and the decreased migration is partially reversed by a RAC1/CDC42 activator. Podocyte-specific deletion of Fat1 in mice induces abnormal glomerular filtration barrier development, leading to podocyte foot process effacement. Knockdown of Fat1 in renal tubular cells reduces migration, decreases active RAC1 and CDC42, and induces defects in lumen formation. Knockdown of fat1 in zebrafish causes pronephric cysts, which is partially rescued by RAC1/CDC42 activators, confirming a role of the two small GTPases in the pathogenesis. These findings provide new insights into the pathogenesis of SRNS and tubulopathy, linking FAT1 and RAC1/CDC42 to podocyte and tubular cell function

The development of unlike induced association-site models to study the phase behaviour of aqueous mixtures comprising acetone, alkanes and alkyl carboxylic acids with the SAFT-γ Mie group contribution methodology

All computational data presented in the figures

The multiscale challenges of biomass fast pyrolysis and bio-oil upgrading: review of the state of art and future research directions

Biomass fast pyrolysis is potentially one of the cheapest routes toward renewable liquid fuels. Its commercialization, however, poses a multi-scale challenge, which starts with the characterization of feedstock, products and reaction intermediates at molecular scales, and continues with understanding the complex reaction network taking place in different reactor configurations, and in the case of catalytic pyrolysis and upgrading on different catalysts. In addition, crude pyrolysis oil is not immediately usable in the current energy infrastructure, due to undesirable properties such as low energy content and corrosiveness as a result of its high oxygenate content. It, therefore, needs to be upgraded and fractionated to desired specifications. While various types of pyrolysis reactors and upgrading technologies are under development, knowledge transfer and closing the gap between theory and application requires model development. In-depth understanding of the reaction mechanisms and kinetics should be combined with the knowledge of multi-scale transport phenomena to enable design, optimization, and control of complex pyrolysis reactors. Finally, underpinning economic and environmental impacts of biofuel production requires expanding the system boundaries to include the overall process and supply chain. The present contribution aims at providing a comprehensive multi-scale review that discusses the state of the art of each of these aspects, as well as their multi-scale interactions. The study is mainly focused on fast pyrolysis, although reference to other types of pyrolysis technologies is made for the sake of comparison and knowledge transfer

MODELISATION OF A FIXED BED REACTOR FOR FISCHER TROPSCH SYNTHESIS WITH DEACTIVATION

International @ BIOVERT+PFOInternational audienceNon

Frittage du catalyseur ŕ base de cobalt au cours de la synthčse FischerTropsch dans un réacteur ŕ lit fixe : mécanisme et modélisation

National @ BIOVERT+PFOInternational audienceNon

Deactivation of a Co/Al2O3 Fischer-Tropsch catalyst by water-induced sintering in slurry reactor: Modeling and experimental investigations

BIOVERT+PFOThe deactivation of cobalt based catalysts in slurry Fischer-Tropsch reactor has been modeled assuming a sintering mechanism which involves the intermediate formation of cobalt oxide layer on metallic nanoparticles. The mechanism, correlating the crystallite size growth to the water to hydrogen concentration ratio in the liquid phase, has been used to describe the activity decline with time on stream. The effect of operating conditions on the rate of sintering is considered. It is found that at the same initial conversion, sintering rate is higher for lower H-2/CO ratios, whereas higher ratios could lead to larger crystallites once operated at constant gas flow rate. The presence of water in the inlet syngas stream also accelerates sintering. The sintering model is then used to describe the deactivation in laboratory-scale slurry reactor. (C) 2013 Elsevier B.V. All rights reserved

Sintering of cobalt-based Fischer Tropsch catalyst in slurry reactor: modeling and experimental investigation

International @ BIOVERT+PFOInternational audienceNon

Mechanistic Modeling of Cobalt Based Catalyst Sintering in a Fixed Bed Reactor under Different Conditions of Fischer-Tropsch Synthesis

BIOVERT+PFOA three-step sintering mechanism is proposed for Co-based catalysts under Fischer-Tropsch reaction conditions. This mechanism includes an intermediate formation of oxide layer on cobalt metal nanoparticles in the presence of water. The partially reversibly oxidized surface accelerates sintering by both reducing the surface energy and enhancing the diffusion rates of cobalt particles. The proposed mechanism is then employed for a fixed-bed unsteady state reactor. The effect of particle growth on the catalytic activity was analyzed within a diverse range of operating conditions (syngas ratio = 1.5-4, water co-feed ratio = 0-6, inert co-feed ratio = 0-6). It is found that, at the same gas space velocity, sintering proceeds faster at higher H-2/CO ratios. At the same initial conversion, a low H-2/CO syngas ratio increases sintering severity, i.e., catalyst deactivation due to the crystallite growth, as it brings about higher relative water partial pressure. Dilution of syngas with different amounts of inert gas does not affect the cobalt sintering rate. Cobalt sintering proceeds more rapidly if water is co-fed during the reaction

Effect of Different Reaction Conditions on the Deactivation of Alumina-Supported Cobalt Fischer-Tropsch Catalysts in a Milli-Fixed-Bed Reactor: Experiments and Modeling

BIOVERT+PFOThis paper focuses on the deactivation of a cobalt-based alumina-supported Fischer-Tropsch catalyst in a milli-fixed-bed reactor under different operating conditions. Different catalyst deactivation behaviors were observed at different syngas H-2/CO ratios and temperatures. The deactivation follows a two-step profile, where the initial deactivation is attributed to sintering, whereas the long-term deactivation is due to carbon deposition or cobalt oxidation on the surface. An unsteady-state semimechanistic model has been developed to represent the data at different temperatures and syngas ratios. This model takes into account cobalt sintering, coke deposition, and surface oxidation