Validation chez les adolescents d'une version francophone d'un instrument de mesure de la peur du jugement négatif d'autrui.

The popularity of the Fear of Negative Evaluation scale (FNE; Watson & Friend, 1969) stems from the centrality of this construct in personality, social and clinical psychology. In order to meet the needs of the Francophone researchers community, Kéroack, Boisvert, and Prévost (1987) traduced the short version of this instrument. Since social anxiety is most salient in adolescence, there is a need for normative and psychometric data for this population. This research aims at documenting the psychometric properties and norms for Francophone adolescents. Five hundred and seventy-eight participants aged from 14 to 19 years completed the French versions of the short FNE and the Social Avoidance and Distress scale. The factorial structure, the internal consistency and the convergent validity analyses confirm the traduction's quality and the questionnaire's validity. Norms are presented separately for females and males. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Nitrous oxide emissions from a fertile grassland in Western Norway following the application of inorganic and organic fertilizers

In Norway, 65 % of the agricultural land is under grassland for feeding ruminants. The objective of the present study was to quantify N₂O emissions from grassland on a fertile sandy loam in Western Norway, and to estimate the response of seasonal N₂O emissions to added inorganic N, cattle slurry (CS) N and clover N. Ammonium nitrate (AN) and CS were applied manually at annual rates of 0, 100, 150, 200 and 250 kg AN-N ha^?1, 80 kg CS-N ha^?1 or as a combination of 200 kg AN-N ha^?1 and 80 kg CS-N ha^?1. Background N₂O emissions were five times higher in summer season 2009 than in 2010, but the relative amount of N₂O derived from AN was constant in both periods, amounting to 0.11 % of applied N. CS had no measurable impact on N₂O emissions in 2009, but 0.15 % of CS-N was emitted as N₂O during summer 2010. In the warm year of 2009, which included a drought period, 1–24 % of the N₂O emissions were attributed to the effect of clover depending on fertilization. Clover had no effect on N₂O fluxes in the cool and moist year 2010. Our results suggest that N₂O emissions in fertile Norwegian grasslands are to a great extent controlled by inter-annual variations in background emissions and variable contribution of biologically fixed N and CS-N.     

Evaluation of two control strategies for a sequencing batch reactor degrading high concentration peaks of 4-chlorophenol

The operation of a sequencing batch reactor (SBR) exposed to high concentration peaks (shock loads) of a toxic compound (4-chlorophenol, 4CP) was evaluated. Two control strategies based on on-line measurements of the dissolved oxygen concentration were tested. The first strategy, called variable timing control (VTC), detects the end of the reaction period to stop it. In the second control strategy, called observer-based time optimal control (OB-TOC), the automated system tries to maintain the critical specific growth rate by controlling the feed rate, i.e. the maximum growth rate when the substrate is toxic. The system operating under the VTC strategy presented a stable and efficient operation when the acclimated microorganisms (to an initial concentration of 350 mg 4CP/L) were exposed to punctual concentration peaks of 700 mg 4CP/L. A 4CP concentration peak higher than or equal to 1050 mg/L disturbed the system (1 month to recover). A 1400 mg/L peak caused strong inhibition that shut down the metabolic activity of the microorganisms, leading to reactor failure. With the OB-TOC strategy, the system was stable and worked efficiently when punctual concentration peaks of 700, 1050 and 1400 mg 4CP/L were fed. The system controlled by the OB-TOC strategy treated 1400 mg 4CP/L in less than 8h without affecting the operation of the reactor. The conclusion is that the OB-TOC strategy is more efficient than the VTC strategy to control a bioreactor when there are variations of concentrations of toxic organic compounds.     

Sol–gel incorporation of silica nanofillers for tuning the anti-corrosion protection of acrylate-based coatings

The aim of the present work is to synthesize through sol–gel approach new hybrid polymeric nanocomposites to be used as coating materials. An acrylic-based polymer was prepared by free-radical copolymerization of two monomers widely used for coatings, namely 2-ethylhexylacrylate (EHA) and glycidyl methacrylate (GMA) bearing epoxy moieties, in which silica nanoparticles were incorporated by in situ acid hydrolysis and subsequent condensation of tetraethoxysilane (TEOS). Glycidoxypropyl trimethoxysilane (GPTS) was used as coupling agent to fine-tune the compatibility between organic and inorganic phases. The morphology, mechanical properties and corrosion resistance of thin films applied on aluminum alloys were optimized by varying the content of silica nanoparticles whose properties were strongly affected by the TEOS/GPTS ratios. Performances of the obtained hybrid materials were scrutinized by atomic force microscopy (AFM), differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), and electrochemical impedance spectroscopy (EIS). Thus it was evidenced that an optimum amount of silica nanoparticles with a precise morphology and composition in term of TEOS/GPTS ratio is needed to maintain good coating barrier properties. Outstanding anti-corrosion protection was reached by using optimized hybrid films.     

Bioprinting of Regenerative Photosynthetic Living Materials

Living materials, which are fabricated by encapsulating living biological cells within a non-living matrix, have gained increasing attention in recent years. Their fabrication in spatially defined patterns that are mechanically robust is essential for their optimal functional performance but is difficult to achieve. Here, a bioprinting technique employing environmentally friendly chemistry to encapsulate microalgae within an alginate hydrogel matrix is reported. The bioprinted photosynthetic structures adopt pre-designed geometries at millimeter-scale resolution. A bacterial cellulose substrate confers exceptional advantages to this living material, including strength, toughness, flexibility, robustness, and retention of physical integrity against extreme physical distortions. The bioprinted materials possess sufficient mechanical strength to be self-standing, and can be detached and reattached onto different surfaces. Bioprinted materials can survive stably for a period of at least 3 days without nutrients, and their life can be further extended by transferring them to a fresh source of nutrients within this timeframe. These bioprints are regenerative, that is, they can be reused and expanded to print additional living materials. The fabrication of the bioprinted living materials can be readily up-scaled (up to ≥70 cm × 20 cm), highlighting their potential product applications including artificial leaves, photosynthetic bio-garments, and adhesive labels.     

Modelling of reciprocating and scroll compressors

This paper presents simple and thermodynamically realistic models of two types of compressors widely used in domestic heat pumps (reciprocating and scroll compressors). These models calculate the mass flow rate of refrigerant and the power consumption from the knowledge of operating conditions and parameters. Some of these parameters may be found in the technical datasheets of compressors whereas others are determined in such a way that the calculated mass flow rate and electrical power match those given in these datasheets.The two models have been tested on five reciprocating compressors and five scroll compressors. This study has been limited to compressors with a maximum electrical power of 10 kW and for the following operating conditions: evaporating temperatures ranging from −20 to 15 °C and condensing temperatures ranging from 15 to 60 °C.The average discrepancies on mass flow rate and power for reciprocating compressors are 1.10 and 1.69% (for different refrigerants: R134a, R404A, R22, R12 and R407C). For scroll compressors, the average discrepancies on mass flow rate and power are 2.42 and 1.04% (for different refrigerants: R134a, R404A, R407C and R22).     

Polyethyleneimine-mediated flocculation of Shewanella oneidensis MR-1: impacts of cell surface appendage and polymer concentration

In wastewater treatment plants, optimizing bacterial flocculation and bacterial sludge dewatering requires a detailed understanding of the concomitant biological and physico-chemical processes governing the action of flocculating agent on living cells. Here we investigate the interactions between polyethyleneimine (PEI, 60,000 g/mol) and Shewanella oneidensis MR-1 lacking or not the lipopolysaccharide (LPS) O-antigen surface structure. Flocculation tests were performed on bacteria with/without LPS O-antigen after being exposed to 0-100 mg/L PEI concentrations. Measurements of electrophoretic mobility and bacterial aggregates size were complemented by transmission electron micrographs and atomic force microscopy images. While low PEI concentrations (<20 mg/L) lead to flocculation of both bare and LPS O-antigen-decorated bacterial strains, the lysis of bacterial membranes occurred at larger polymer concentrations for the latter, which highlights the protective role of LPS O-antigen against harmful PEI-mediated membrane alterations. Depending on polymer concentration, two types of bacterial aggregates are identified: one that solely integrates bacterial cells, and another that includes both cells and cell residues resulting from lysis (membrane and/or LPS fragments, and inner cell content materials). The latter is expected to significantly contribute to water entrapping in sludge and thus lower dewatering process efficiency.     

Students and instructors perspective on blended synchronous learning in a Canadian graduate program

Blended synchronous learning (BSL) represents several contexts that enable to bring remote students into the classroom, in real time, by the means of videoconferencing, web conferencing and virtual world. As BSL seems to be more and more implemented in many higher education institutions, especially in the current context of the COVID-19 pandemic, and given the recent interest and scarce published research in BSL, more studies are needed on this kind of learning. The purpose of this research was to explore students and instructors perspective regarding their experience in BSL, according to three dimensions: pedagogy, technology and organization/logistics. To meet the study objective, a qualitative methodology was adopted. The study participants were remote students (n = 4) and face-to-face students (n = 4) enrolled in a graduate program in education offering only blended synchronous courses, and instructors (n = 5) in this program. Semi-structured interviews were selected as the data collection method. Nine sub-themes in reference to the three dimensions emerged from the study participants. They have also highlighted some challenges associated with BSL. The results reported in this study should provide faculties and higher education administrators with additional information and guidance, based on empirical data, on the use of BSL if they wish to implement it in academic programs. Moreover, in regard to the challenges revealed by the study participants, the results will permit to surpass the obstacles when implementing BSL successfully.     

Labeling ribonuclease S with a 3 nm Au nanoparticle by two-step assembly

We label ribonuclease S with a 3 nm Au nanoparticle (NP) by utilizing its two-piece structure. One portion, S-peptide, is mutated with a unique NP attachment site. NP-peptide self-assembles with the other portion, S-protein, to form an active enzyme. NP mobility decreases with peptide labeling and S-protein association. Surface plasmon shifts support conjugation. Higher S-peptide coverages on the NP surface reduce nonspecific adsorption, while sterically hindering assembly of RNaseS. Thiols displace nonspecific adsorption, maximizing site-specific labeling.     

Stereocomplex block copolymer micelles: core-shell nanostructures with enhanced stability

Monodisperse stereocomplex block copolymer micelles were obtained through the self-assembly of equimolar mixtures of poly(ethylene glycol)-block-poly(l-lactide) and poly(ethylene glycol)-block-poly(d-lactide) in water. These micelles possessed partially crystallized cores and mean hydrodynamic diameters ranging from 31 to 56 nm, depending on the lactide content. They exhibited kinetic stability and redispersion properties superior to micelles prepared with isotactic or racemic polymers alone. This study demonstrates the advantages of stereocomplex formation in the design of stabilized water-soluble nanoparticles.