Isobutanol production from cellobionic acid in Escherichia coli.

BackgroundLiquid fuels needed for the global transportation industry can be produced from sugars derived from plant-based lignocellulosics. Lignocellulosics contain a range of sugars, only some of which (such as cellulose) have been shown to be utilizable by microorganisms capable of producing biofuels. Cellobionic acid makes up a small but significant portion of lignocellulosic degradation products, and had not previously been investigated as an utilizable substrate. However, aldonic acids such as cellobionic acid are the primary products of a promising new group of lignocellulosic-degrading enzymes, which makes this compound group worthy of study. Cellobionic acid doesn't inhibit cellulose degradation enzymes and so its inclusion would increase lignocellulosic degradation efficiency. Also, its use would increase overall product yield from lignocellulose substrate. For these reasons, cellobionic acid has gained increased attention for cellulosic biofuel production.ResultsThis study describes the discovery that Escherichia coli are naturally able to utilize cellobionic acid as a sole carbon source with efficiency comparable to that of glucose and the construction of an E. coli strain able to produce the drop-in biofuel candidate isobutanol from cellobionic acid. The gene primarily responsible for growth of E. coli on cellobionic acid is ascB, a gene previously thought to be cryptic (expressed only after incurring specific mutations in nearby regulatory genes). In addition to AscB, the ascB knockout strain can be complemented by the cellobionic acid phosphorylase from the fungus Neurospora crassa. An E. coli strain engineered to express the isobutanol production pathway was successfully able to convert cellobionic acid into isobutanol. Furthermore, to demonstrate potential application of this strain in a sequential two-step bioprocessing system, E. coli was grown on hydrolysate (that was degraded by a fungus) and was successfully able to produce isobutanol.ConclusionsThese results demonstrate that cellobionic acid is a viable carbon source for biofuel production. This work suggests that with further optimization, a bacteria-fungus co-culture could be used in decreased-cost biomass-based biofuel production systems

Proposed Vertical Expansion Tunnel

It is proposed that the adverse effects from secondary diaphragm rupture in an expansion tunnel may be reduced or eliminated by orienting the tunnel vertically, matching the test gas pressure and the accelerator gas pressure, and initially separating the test gas from the accelerator gas by density stratification. This proposed configuration is termed the vertical expansion tunnel. Two benefits are 1) the removal of the diaphragm particulates in the test gas after its rupture, and 2) the elimination of the wave system that is a result of a real secondary diaphragm having a finite mass and thickness. An inviscid perfect-gas analysis and quasi-one-dimensional Euler computations are performed to find the available effective reservoir conditions (pressure and mass specific enthalpy) and useful test time in a vertical expansion tunnel for comparison to a conventional expansion tunnel and a reflected-shock tunnel. The maximum effective reservoir conditions of the vertical expansion tunnel are higher than the reflected-shock tunnel but lower than the expansion tunnel. The useful test time in the vertical expansion tunnel is slightly longer than the expansion tunnel but shorter than the reflected-shock tunnel. If some sacrifice of the effective reservoir conditions can be made, the vertical expansion tunnel could be used in hypervelocity ground testing without the problems associated with secondary diaphragm rupture

Informer, consulter, concerter, codécider pour aménager : Dispositifs de partage des informations et des connaissances pour les processus d'aménagement concerté (DPICPAC) : rapport final

Ce projet applique une approche interdisciplinaire afin de tester l'hypothèse générale et communément admise que la disponibilité et la pertinence de l'information sont cruciaux pour le succès des processus d'aménagement du territoire participatifs (ou collaboratifs) qui impliquent plusieurs groupes d'acteurs, y compris fonctionnaires, des professionnels, des représentants des propriétaires fonciers et du grand public. Cette hypothèse est fondée sur le point de vue "instrumental" que lorsque l'information appropriée est disponible au moment opportun dans le processus de planification, alors il favorisera la réussite de ce processus. Une deuxième hypothèse fondée sur les principes de la «gouvernance» attribue une importance primordiale aux motivations de tous les acteurs et institutions représentés dans le processus de planification. Une troisième hypothèse que la négociation d'un ensemble de règles concernant les rôles et les responsabilités des acteurs et des institutions ainsi que la disponibilité de données appropriées, de statistiques et d'informations sont nécessaires pour une planification collaborative réussie. Cette recherche comprend des études de cas dans la région de langue française de la Suisse (Genève et Lausanne) dans le but d'analyser et d'expliquer comment et pourquoi les statistiques et les informations disponibles peuvent ou non être utilisés efficacement dans les processus décisionnels. La recherche propose un ensemble de lignes directrices pour l'application efficace de ces types de processus dans le futur

Effect of local anesthetics on viability and differentiation of various adult stem/progenitor cells

Background Local anesthetics (LAs) are widely used to control pain during various clinical treatments. One of the side effects of LAs, cytotoxicity, has been investigated in various cells including stem/progenitor cells. However, our understanding of the effects of LAs on the differentiation capacity of stem/progenitor cells still remains limited. Therefore, a comparative study was conducted to investigate the effects of multiple LAs on viability and multi-lineage differentiation of stem/progenitor cells that originated from various adult tissues. Method Multiple types of stem/progenitor cells, including bone marrow mesenchymal stem/progenitor cells (MSCs), dental pulp stem/progenitor cells (DPSCs), periodontal ligament stem/progenitor cells (PDLSCs), and tendon-derived stem/progenitor cells, were either obtained from a commercial provider or isolated from adult human donors. Lidocaine (LD) and bupivacaine (BP) at various doses (1×, 0.75×, 0.5×, and 0.25× of each physiological dose) were applied to the different stem/progenitor cells for an hour, followed by induction of fibrogenic, chondrogenic, osteogenic, and adipogenic differentiation. Live/dead and MTT assays were performed at 24 h after the LD or BP treatment. At 2 weeks, qRT-PCR was conducted to evaluate the gene expressions associated with differentiation. After 4 weeks, multiple biochemical staining was performed to evaluate matrix deposition. Results At 24 h after LD or BP treatment, 1× and 0.75× physiological doses of LD and BP showed significant cytotoxicity in all the tested adult stem/progenitor cells. At 0.5×, BP resulted in higher viability than the same dose LD, with variance between cell types. Overall, the gene expressions associated with fibrogenic, chondrogenic, osteogenic, and adipogenic differentiation were attenuated in LD or BP pre-treated stem/progenitor cells, with notable dose-effect and dependence on types. In contrast, certain doses of LD and/or BP were found to increase specific gene expression, depending on the cell types. Conclusion Our data suggest that LAs such as LD and BP affect not only the viability but also the differentiation capacity of adult stem/progenitor cells from various anatomical sites. This study sheds light on stem cell applications for tissue regeneration in which isolation and transplantation of stem cells frequently involve LA administration

Evaporative attachment of slow electrons to alkali nanoclusters

The abundance spectrum of Na^-_{n~7-140} anions formed by low energy electron attachment to free nanoclusters is measured to be strongly and nontrivially restructured with respect to the neutral precursor beam. This restructuring is explained in quantitative detail by a general framework of evaporative attachment: an electron is captured by the long-range polarization potential, its energy is transferred into thermal vibrations, and dissipated by evaporative cooling. The data also affirm a formulated relation between the binding energies of cationic, neutral, and anionic clusters, and an adjustment to the prior values of dimer evaporation energies.Comment: 9 pages, 3 figures, revise

Computer analysis of cardiac radionuclide data

Gamma-camera tomography gives uniform in-plane and cross-plane resolution with propagation of the defect from one plane to another determined only by the usual camera-collimator resolution. These images may be reformatted by computer to portray slices in any orientation. Cross plane resolution is slightly worse than for the other methods, but it is uniform. The efficiency is less than either quadrant slant hole or seven pinhole apertures. Rotating cameras are not portable nor can they be used for dynamic studies.Both slant hole collimators and seven pinhole apertures distort the object in the depth dimension because of the limited viewing angle. The slant hole geometry provides somewhat better sampling and less plane-to-plane cross talk especially for the more distant planes. The full width half maximum of the depth response is not a sensitive indicator of this problem because the depth response function has very long tails.To date, best overall performance of the limited angle methods is offered by the 40[deg] slant hole collimator on a large field-of-view camera. This, however, is not a portable unit and has a field-of-view too small for about 10% of the patients.Seven pinhole imaging offers the advantage of having been well studied by a number of institution.87-90 A large pool of normal patient studies exists and the performance is well documented. Although the seven pinhole alone is suited to dynamic studies, any of the methods may be adapted to multigated studies.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/25165/1/0000603.pd

Mitochondrial Hâ‚‚Oâ‚‚ emission and cellular redox state link excess fat intake to insulin resistance in both rodents and humans

High dietary fat intake leads to insulin resistance in skeletal muscle, and this represents a major risk factor for type 2 diabetes and cardiovascular disease. Mitochondrial dysfunction and oxidative stress have been implicated in the disease process, but the underlying mechanisms are still unknown. Here we show that in skeletal muscle of both rodents and humans, a diet high in fat increases the Hâ‚‚Oâ‚‚-emitting potential of mitochondria, shifts the cellular redox environment to a more oxidized state, and decreases the redox-buffering capacity in the absence of any change in mitochondrial respiratory function. Furthermore, we show that attenuating mitochondrial Hâ‚‚Oâ‚‚ emission, either by treating rats with a mitochondrial-targeted antioxidant or by genetically engineering the overexpression of catalase in mitochondria of muscle in mice, completely preserves insulin sensitivity despite a high-fat diet. These findings place the etiology of insulin resistance in the context of mitochondrial bioenergetics by demonstrating that mitochondrial Hâ‚‚Oâ‚‚ emission serves as both a gauge of energy balance and a regulator of cellular redox environment, linking intracellular metabolic balance to the control of insulin sensitivity. Original version available at http://www.jci.org/articles/view/3704

Étude du frittage non-conventionnel de céramiques de type YAG:Nd en présence d’ajout de silice

L’objectif de cette étude était de cerner l’influence du procédé de frittage non conventionnel employé pour la mise en forme des pièces (frittage SPS ou post-frittage HIP) sur l’activation des processus densifiants. Il s’avère qu’un traitement SPS des poudres initiales permet d’abaisser la température de début de frittage et conduit dans certaines conditions à des pièces translucides ou transparentes. L’influence de la silice, introduit comme ajout de frittage, et du néodyme, introduit comme dopant, est également discutée dans ce travail. Le post-frittage HIP, quant à lui, permet l’élimination de la porosité résiduelle dans les échantillons, ce qui conduit à la transparence des pièces réalisées

Walk-through angina phenomenon demonstrated by graded exercise radionuclide ventriculography: Possible coronary spasm mechanisms

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24073/1/0000325.pd