Genetics and functional genomics of type 2 diabetes mellitus

Genome-wide studies of transcription in the skeletal muscle of type 2 diabetic patients have identified coordinated changes in the expression of genes involved in oxidative phosphorylation, and have underlined the central role of the oxidative-phosphorylation regulator, PCG1α. These findings help unravel the complex pathogenesis and inheritance of polygenic type 2 diabetes mellitus

OPTIMISATION DE L’HYDRODYNAMIQUE D’UN PHOTOBIOREACTEUR TUBULAIRE DE TYPE AIRLIFT FAVORISANT LA FORMATION DE BIOFLOCS

L'augmentation de la population mondiale et de l'urbanisation qui sont à l'origine du changement climatique ont poussé les gouvernements à imposer des politiques pour réduire les émissions des gaz à effet de serre (GES). Par ailleurs les procédés de traitement biologique des eaux usées sont pénalisés énergétiquement et ils ne sont pas durables par leur consommation d’oxygène, les nuisances causées par les boues et les odeurs et par l’émission des gaz à effet de serre particulièrement le CO2. L'utilisation des microalgues pour traiter les eaux usées fait l'objet d'une attention croissante dans le monde car elle est considérée comme un nouveau moyen de traitement des eaux usées. En particulier, l'intégration de microalgues dans le cadre de procédés d’épuration multitrophiques permet d’envisager des solutions de traitement des eaux sans apport d'O2 et sans rejet de CO2. Il est communément admis que la culture à grande échelle et l'application commerciale des microalgues sont limitées par le développement du photobioréacteur (PBR). Bien qu'il existe des nombreux types de PBR pour la culture pure de microalgues dans des milieux de culture définis, un nouveau design de PBR doit être envisagé dans le cas de cultures multitrophiques utilisées pour l’épuration des eaux. Un PBR tubulaire avec airlift a donc été conçu. Un pilote a été construit pour étudier les aspects hydrodynamiques et le transfert de matière, dans le but d’optimiser le traitement des eaux usées Afin de minimiser la formation de biofilm sur la paroi et limiter la diffusion de la lumière, un écoulement avec des flocs des microalgues est généré. Le PBR d’étude conçue a servi de base aux études de transferts hydrodynamiques et biologiques. Les études hydrodynamiques (traçage conductimétrique) ont donné accès aux vitesses d’écoulement, le temps de circulation et le temps de mélange. Différents débits de gaz et différents types et positions de l’injecteurs de gaz ont été testés. En complément, les performances de transfert de matière gaz-liquide du réacteur ont été déterminées, afin de confirmer la possibilité de transférer efficacement l’oxygène produit photosynthétiquement Sur base des informations expérimentales collectées, le design de PBR et les conditions opératoires optimales pour une culture active de microalgues ont été optimisés. Les facteurs pris en compte sont le temps de séjour hydraulique, le transfert de matière gaz-liquide et le temps de mélange. L’objectif est d’assurer une distribution adéquate (uniforme et dans la gamme optimale) des concentrations en nutriments, en gaz O2 et CO2, ainsi que de la lumière, dans l’ensemble du réacteur.TRAITEMENT DES EAUX USEES SANS APPORT D’O2 ET SANS DEGAGEMENT DE CO2 ET DEVELOPPEMENT D’UN PHOTOBIOREACTEUR INNOVANT3. Good health and well-bein

Convective Drying of Mixtures of Sewage Sludge and Sawdust in a Fixed Bed

This work is part of a project aiming at developing a renewable fuel for gasification purposes, through the convective drying of sludge/wood mixtures. The first step consists in characterizing the drying behaviour of sludge/sawdust mixtures, in a convective fixed bed dryer. In particular, the influence of the mixing step (no mixing against 30 s at 40 rpm) and the sawdust/sludge ratio (1/9, 2/8, 3/7 and 4/6 on a dry basis) have been investigated, as well as the drying temperature (50 °C, 80 °C and 110 °C). As showed in a previous work, the addition of dry matter into sludge has an impact on the initial 3D structure of the bed of extrudates to be dried. Moreover, it is well known that the volume shrinkage occurring during sludge drying will affect the drying velocity. In this study, X-ray tomography, a non-invasive imaging technique, is used to assess changes in volume, porosity and exchange surface between the beginning and the end of the drying process. Results first confirm the importance of the mixing step on the drying behaviour: the drying rate of the mixed sludge is slower than the one of original sludge. Nevertheless the addition of sawdust is shown to have a positive impact on the drying process from mass ratio of 2/8, with observed drying rates higher than for the original sludge. During the whole drying process, the volume and exchange surface of the sample increase and the porosity decreases as the mass ratio increases. These results indicate that the air and the sample contact more fully with more sawdust addition, resulting from bed expansion and exchange surface increase. Hence, the heat and mass transfer efficiency between the air and the material increases and consequently the drying rate. Further work will be done in order to assess the impact of the drying temperature and to characterize the behaviour of these samples during pyrolysis using thermo gravimetric analysis

A First Insight on the Interaction between Desiccation Cracking and Water Transfer in a Luvisol of Belgium

peer reviewedThe present paper presents the interactions between water retention/evaporation and cracking during the desiccation of intact and disturbed Belgian Luvisol. The disturbed (DS) and undisturbed (NDS) samples (reduced-tillage-residue-in (RTRI) and conventional-tillage-residue-out (CTRO)) were collected from an agricultural field in Gembloux, Wallonia, Belgium. The drying experiment took place in controlled laboratory conditions at 25 °C. Moisture content, soil suction and surface cracks were monitored with a precision balance, a tensiometer and a digital camera, respectively. The image processing and analysis were performed using PCAS® and ImageJ® software. The results showed that crack formation was initiated at a stronger negative suction and a lower water content (Wc) in DS > CTRO > RTRI. The suction and the crack propagation were positively correlated until 300 kPa for the DS and far beyond the wilting point for the NDS. For the NDS, the cracking accelerated after reaching the critical water content (~20% Wc) which arrived at the end of the plateau of evaporation (40 h after crack initiation). The Krischer curve revealed that the soil pore size > 50 µm, and that it is likely that cracks are important parameters for soil permeability. The soil structure and soil fibre content could influence the crack formation dynamic during drying. The agricultural tillage management also influences the crack propagation. As retention and conductivity functions are affected by cracks, it is likely that the movement of fluids in the soil will also be affected by the cracks following a desiccation period (i.e., when the cracked soil is rewetted)

Recent Evolutions and Trends in the Use of Computer Aided Chemical Engineering for Educational Purposes at the University of Liège

peer reviewedThe present paper addresses the evolution and perspectives in the teaching of CAPE methods in the Department of Chemical Engineering at the University of Liège. The transition that happened in the 90ies with the arrival of commercial software is highlighted, as the learning outcomes evolved from the ability of building programs to solve chemical engineering problems towards the ability to use complex commercial software and to understand their limitations. Moreover, CAPE methods were extended to non-dedicated CAPE courses, which is illustrated here by the goals and challenges of their use in courses like “Reactor Engineering” and “Life Cycle Analysis”. It was observed that students sometimes assume that CAPE softwares provide straightforward and trustworthy solutions without the need of understanding their mathematical bases and assumptions. Thus, solutions to make students aware of these limitations are proposed, including the creation of an integrated project focussing on complex multi-disciplinary issues, evidencing the need for critical input from the operator

An engineered baculoviral protein and DNA co-delivery system for CRISPR-based mammalian genome editing

CRISPR-based DNA editing technologies enable rapid and accessible genome engineering of eukaryotic cells. However, the delivery of genetically encoded CRISPR components remains challenging and sustained Cas9 expression correlates with higher off-target activities, which can be reduced via Cas9-protein delivery. Here we demonstrate that baculovirus, alongside its DNA cargo, can be used to package and deliver proteins to human cells. Using protein-loaded baculovirus (pBV), we demonstrate delivery of Cas9 or base editors proteins, leading to efficient genome and base editing in human cells. By implementing a reversible, chemically inducible heterodimerization system, we show that protein cargoes can selectively and more efficiently be loaded into pBVs (spBVs). Using spBVs we achieved high levels of multiplexed genome editing in a panel of human cell lines. Importantly, spBVs maintain high editing efficiencies in absence of detectable off-targets events. Finally, by exploiting Cas9 protein and template DNA co-delivery, we demonstrate up to 5% site-specific targeted integration of a 1.8 kb heterologous DNA payload using a single spBV in a panel of human cell lines. In summary, we demonstrate that spBVs represent a versatile, efficient and potentially safer alternative for CRISPR applications requiring co-delivery of DNA and protein cargoes

Functional annotations of diabetes nephropathy susceptibility loci through analysis of genome-wide renal gene expression in rat models of diabetes mellitus

<p>Abstract</p> <p>Background</p> <p>Hyperglycaemia in diabetes mellitus (DM) alters gene expression regulation in various organs and contributes to long term vascular and renal complications. We aimed to generate novel renal genome-wide gene transcription data in rat models of diabetes in order to test the responsiveness to hyperglycaemia and renal structural changes of positional candidate genes at selected diabetic nephropathy (DN) susceptibility loci.</p> <p>Methods</p> <p>Both Affymetrix and Illumina technologies were used to identify significant quantitative changes in the abundance of over 15,000 transcripts in kidney of models of spontaneous (genetically determined) mild hyperglycaemia and insulin resistance (Goto-Kakizaki-GK) and experimentally induced severe hyperglycaemia (Wistar-Kyoto-WKY rats injected with streptozotocin [STZ]).</p> <p>Results</p> <p>Different patterns of transcription regulation in the two rat models of diabetes likely underlie the roles of genetic variants and hyperglycaemia severity. The impact of prolonged hyperglycaemia on gene expression changes was more profound in STZ-WKY rats than in GK rats and involved largely different sets of genes. These included genes already tested in genetic studies of DN and a large number of protein coding sequences of unknown function which can be considered as functional and, when they map to DN loci, positional candidates for DN. Further expression analysis of rat orthologs of human DN positional candidate genes provided functional annotations of known and novel genes that are responsive to hyperglycaemia and may contribute to renal functional and/or structural alterations.</p> <p>Conclusion</p> <p>Combining transcriptomics in animal models and comparative genomics provides important information to improve functional annotations of disease susceptibility loci in humans and experimental support for testing candidate genes in human genetics.</p

Relevance of accelerated conditions for the study of monoethanolamine degradation in post-combustion CO2 capture.

Solvent degradation represents one of the main operational drawbacks of the post-combustion CO2 capture process. Degradation not only induces additional costs for solvent make-up, it also impacts the process efficiency and its environmental penalty due to the emission of various degradation products. There is still a gap of knowledge about the influence of process operating conditions on degradation, making it currently impossible to predict the solvent degradation rate in CO2 capture plants. Morever, the reaction mechanisms corresponding to solvent degradation are very slow, significantly complicating its study in industrial units. In the present work, appropriate experimental equipment and analytical methods are developed for accelerating the degradation of monoethanolamine solvents (MEA). The relevance of accelerated conditions is established by comparing artificially degraded solvent samples with degraded solvent samples from industrial CO2 capture pilot plants. Two approaches are evaluated implying either discontinuous or continuous gas feed, this latest being the most representative of industrial degradation. The respective influences of the gas feed composition and the gas-liquid transfer are evidenced and quantified. Finally, the present study leads to a better understanding of solvent degradation in the CO2 capture process with MEA. More generally, it also evidences that accelerated conditions at laboratory-scale may provide relevant information for the study of slow phenomena taking place in large-scale industrial processes. Further works include the development of a kinetic model for MEA solvent degradation and the extension of this methodology to other promising solvents in order to facilitate the operation and large-scale deployment of CO2 capture