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Aluha J.,University Of Sherbrookeqc | Abatzoglou N.,University Of Sherbrookeqc
Journal of Industrial and Engineering Chemistry | Year: 2017

Two carbon-supported Fischer–Tropsch Synthesis (FTS) catalysts with ternary metallic formulations (10% Mo–70% Co–20% Fe and 10% Ni–70% Co–20% Fe) were synthesized through suspension plasma-spray (SPS) technology. Their average particle size determined by Transmission Electron Microscopy was 8.4 and 13.3 nm respectively and their BET specific surface areas were between 69–85 m2 g−1. As their analogous monometallic and bimetallic formulations presented in previous publications, these catalysts were both non-porous and nanometric with Scanning Electron Microscopy showing uniform metal-nanoparticle distribution in the carbon-support matrix. FTS test conditions in a 3-phase continuously stirred-tank slurry reactor operated for 24 h were: 260 °C, 2 MPa pressure, H2:CO = 2, gas hourly specific velocity = 3600 cm3 h−1 g−1 of catalyst. Basing catalyst performance on the bimetallic 80% Co–20% Fe/C catalyst, Ni-addition enhanced catalyst activity from ∼42 to 50% CO conversion, and boosted selectivity towards gasoline fraction (C5–C12) from ∼19 to 50%. Enriching the catalyst-surface acidity by Mo-promotion improved selectivity for both gasoline-fraction (19 → 33%) and the C5–C20 fraction (74 → 87%) and lowered H2O production by 30%, although at lower CO conversion (∼38%). The catalysts’ α-values were ∼0.8 in the C10+ region, and from mass balance their estimated H2 efficiency decreased in the order of Mo–Co–Fe/C >> Co-Fe/C > Ni–Co–Fe/C. © 2017 The Korean Society of Industrial and Engineering Chemistry

Alamargot D.,University Paris Est Creteil | Morin M.-F.,University Of Sherbrookeqc
Human Movement Science | Year: 2015

We sought to ascertain how handwriting with a plastic-tipped pen on the screen of a digital tablet affects graphomotor execution in students, compared with handwriting on paper with a ballpoint pen. We predicted that the modification to propriokinesthetic feedback induced by the screen/plastic tip combination would differently disturb younger and older students, who rely on perceptual feedback either to form letters (former) or to adjust movement execution (latter). Twenty-eight students from Grades Two and Nine were asked to handwrite the alphabet and their names and surnames under the two conditions. Kinematics were recorded using the tablet, controlled by Eye and Pen software. Results showed that handwriting on the tablet surface with a plastic-tipped pen primarily affected pen pauses in the second graders and pen movements in the ninth graders, suggesting a disturbance in segment trajectory calculation in the younger participants and reduced control of muscular adjustment in the older children. © 2015 Elsevier B.V..

Blondin D.P.,Université de Sherbrooke | Labbe S.M.,University of Québec | Phoenix S.,Université de Sherbrooke | Phoenix S.,University Of Sherbrookeqc | And 5 more authors.
Journal of Physiology | Year: 2015

Key points: Both brown adipose tissue (BAT) and skeletal muscle activation contribute to the metabolic response of acute cold exposure in healthy men even under minimal shivering. Activation of adipose tissue intracellular lipolysis is associated with BAT metabolic response upon acute cold exposure in healthy men. Although BAT glucose uptake per volume of tissue is important, the bulk of glucose turnover during cold exposure is mediated by skeletal muscle metabolic activation even when shivering is minimized. Cold exposure stimulates the sympathetic nervous system (SNS), triggering the activation of cold-defence responses and mobilizing substrates to fuel the thermogenic processes. Although these processes have been investigated independently, the physiological interaction and coordinated contribution of the tissues involved in producing heat or mobilizing substrates has never been investigated in humans. Using [U-13C]-palmitate and [3-3H]-glucose tracer methodologies coupled with positron emission tomography using 11C-acetate and 18F-fluorodeoxyglucose, we examined the relationship between whole body sympathetically induced white adipose tissue (WAT) lipolysis and brown adipose tissue (BAT) metabolism and mapped the skeletal muscle shivering and metabolic activation pattern during a mild, acute cold exposure designed to minimize shivering response in 12 lean healthy men. Cold-induced increase in whole-body oxygen consumption was not independently associated with BAT volume of activity, BAT oxidative metabolism, or muscle metabolism or shivering intensity, but depended on the sum of responses of these two metabolic tissues. Cold-induced increase in non-esterified fatty acid (NEFA) appearance rate was strongly associated with the volume of metabolically active BAT (r = 0.80, P = 0.005), total BAT oxidative metabolism (r = 0.70, P = 0.004) and BAT glucose uptake (r = 0.80, P = 0.005), but not muscle glucose metabolism. The total glucose uptake was more than one order of magnitude greater in skeletal muscles compared to BAT during cold exposure (674 ± 124 vs. 12 ± 8 μmol min-1, respectively, P < 0.001). Glucose uptake demonstrated that deeper, centrally located muscles of the neck, back and inner thigh were the greatest contributors of muscle glucose uptake during cold exposure due to their more important shivering response. In summary, these results demonstrate for the first time that the increase in plasma NEFA appearance from WAT lipolysis is closely associated with BAT metabolic activation upon acute cold exposure in healthy men. In humans, muscle glucose utilization during shivering contributes to a much greater extent than BAT to systemic glucose utilization during acute cold exposure. © 2014 The Physiological Society.

Adkar-Purushothama C.R.,Université de Sherbrooke | Brosseau C.,University Of Sherbrookeqc | Gigu E Re T.,Université de Sherbrooke | Sano T.,Hirosaki University | And 2 more authors.
Plant Cell | Year: 2015

The tomato (Solanum lycopersicum) callose synthase genes CalS11-like and CalS12-like encode proteins that are essential for the formation of callose, a major component of pollen mother cell walls; these enzymes also function in callose formation during pathogen infection. This article describes the targeting of these callose synthase mRNAs by a small RNA derived from the virulence modulating region of two Potato spindle tuber viroid variants. More specifically, viroid infection of tomato plants resulted in the suppression of the target mRNAs up to 1.5-fold, depending on the viroid variant used and the gene targeted. The targeting of these mRNAs by RNA silencing was validated by artificial microRNA experiments in a transient expression system and by RNA ligase-mediated rapid amplification of cDNA ends. Viroid mutants incapable of targeting callose synthase mRNAs failed to induce typical infection phenotypes, whereas a chimeric viroid obtained by swapping the virulence modulating regions of a mild and a severe variant of Potato spindle tuber viroid greatly affected the accumulation of viroids and the severity of disease symptoms. These data provide evidence of the silencing of multiple genes by a single small RNA derived from a viroid. © 2015 American Society of Plant Biologists. All rights reserved.

Mostafa A.M.,University Of Sherbrookeqc | Yahia A.,University Of Sherbrookeqc
Cement and Concrete Research | Year: 2016

The structural build-up of cement suspensions at rest is a complex phenomenon affected by both physical and chemical structurations. Better understanding of this phenomenon relies on the efficiency of measurement approach. Dynamic rheometry was used to investigate the evolution of both storage modulus and phase angle of cement and inert calcium carbonate suspensions. Two independent build-up indices were proposed to identify the rest time needed to build a percolated elastic network and its rigidification rate with time. The structural build-up of various cement suspensions was evaluated using the proposed indices. These indices were then compared to the well-known thixotropic index (Athix.). It was found that combining the percolation time and the rigidification rate can provide deeper insight into the structuration process of cement suspensions. Furthermore, these indices were found to be well-correlated to the decay in lateral pressure of cement suspensions. © 2016 Elsevier Ltd. All rights reserved.

Objective: To review the issues with setting goals of care for patients with advanced dementia, describe the respective roles of the physician and the patient's family in the decision-making process, and suggest ways to support families who need more information about the care options. Sources of information: Ovid MEDLINE was searched for relevant articles that were published before March 7, 2014. There were no level I studies identified; most articles provided level III evidence. Main message: For patients with advanced dementia, their families have an important role in medical decision making. Families should receive timely information about the course of dementia and the care options. They need to understand that a palliative approach to care might be appropriate and does not mean abandonment of the patient. They might also want clarification about their role in the decision-making process, especially if withholding or withdrawing life-prolonging measures are considered. Conclusion: Physicians should consider advanced dementia as a terminal disease for which there is a continuum of care that goes from palliative care with life-extending measures to symptomatic interventions only. Clarification of goals of care and family education are of paramount importance to avoid unwanted and burdensome interventions. © 2015, College of Family Physicians of Canada. All rights reserved.

Objective: To answer frequently asked questions about management of end-stage pneumonia, poor nutritional intake, and dehydration in advanced dementia. Sources of information: Ovid MEDLINE was searched for relevant articles published until February 2015. No level I studies were identified; most articles provided level III evidence. The symptom management suggestions are partially based on recent participation in a Delphi procedure to develop a guideline for optimal symptom relief for patients with pneumonia and dementia. Main message: Feeding tubes are not recommended for patients with end-stage dementia. Comfort feeding by hand is preferable. Use of parenteral hydration might be helpful but can also contribute to discomfort at the end of life. Withholding or withdrawing artificial nutrition and hydration is generally not associated with manifestations of discomfort if mouth care is adequate. Because pneumonia usually causes considerable discomfort, clinicians should pay attention to symptom control. Sedation for agitation is often useful in patients with dementia in the terminal phase. Conclusion: Symptomatic care is an appropriate option for end-stage manifestations of advanced dementia. The proposed symptom management guidelines are based on a literature review and expert consensus. © 2015, College of Family Physicians of Canada. All rights reserved.

Verdiere K.,University Of Sherbrookeqc | Panneton R.,University Of Sherbrookeqc | Elkoun S.,University Of Sherbrookeqc
Applied Acoustics | Year: 2016

In this paper, an approach to predict the sound absorption coefficient and sound transmission loss of a parallel assembly of hollow cylinders is presented. This approach is based on image processing and the Parallel Transfer Matrix Method (PTMM) using four Johnson-Champoux-Allard effective fluids. First, effective parameters of each fluid are identified using geometrical considerations and numerical simulations. Then, the approach is validated for a stack of uniform plastic straws, and used to model a natural stack of non-uniform switchgrass straws. Finally, two parametric studies are conducted to evaluate the effects of the geometric parameters of the straws on the acoustic behavior of their stack. It is shown that there are optimal parameters that maximize the acoustic behavior at specific frequencies. © 2015 Elsevier Ltd. All rights reserved.

Duclos-Cianci G.,University Of Sherbrookeqc | Poulin D.,University Of Sherbrookeqc
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2015

In leading fault-tolerant quantum-computing schemes, accurate transformations are obtained by a two-stage process. In a first stage, a discrete universal set of fault-tolerant operations is obtained by error-correcting noisy transformations and distilling resource states. In a second stage, arbitrary transformations are synthesized to desired accuracy by combining elements of this set into a circuit. Here we present a scheme that merges these two stages into a single one, directly distilling complex transformations. We find that our scheme can reduce the total overhead to realize certain gates by up to a few orders of magnitude. In contrast to other schemes, this efficient gate synthesis does not require computationally intensive compilation algorithms and a straightforward generalization of our scheme circumvents compilation and synthesis altogether. © 2015 American Physical Society.

Landon-Cardinal O.,California Institute of Technology | Yoshida B.,California Institute of Technology | Poulin D.,University Of Sherbrookeqc | Preskill J.,California Institute of Technology
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2015

A two-dimensional topologically ordered quantum memory is well protected against error if the energy gap is large compared to the temperature, but this protection does not improve as the system size increases. We review and critique some recent proposals for improving the memory time by introducing long-range interactions among anyons, noting that instability with respect to small local perturbations of the Hamiltonian is a generic problem for such proposals. We also discuss some broader issues regarding the prospects for scalable quantum memory in two-dimensional systems. © 2015 American Physical Society.

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