Changes in the sensitivity to appetitive and aversive arousal across adulthood.

In 2 cross-sectional studies, the authors examined age-related differences in the evaluation of emotional stimuli in 2 community samples, with participants ranging in age from young to older adulthood (18–81 years old). Pictures of the International Affective Picture System were used in Study 1, and written verbs were used in Study 2. Participants rated these stimuli along the 2 major affective dimensions of hedonic valence and emotional arousal, thus yielding a 2-dimensional affective space for each participant. Young adults showed the expected pattern of 2 distinct clusters of stimuli in this space, representing increasing pleasantness (appetitive activation) and unpleasantness (aversive activation) with increasing emotional arousal. In contrast, for older adults, emotional valence and arousal ratings were linearly related: Low-arousing stimuli were rated as most pleasant, and high-arousing stimuli were rated as most unpleasant. When regressed on age, these changes revealed a gradual decrease of appetitive activation (i.e., the relationship between pleasure and arousal) across adulthood and a linear increase in aversive activation (i.e., the relationship between displeasure and arousal). These results extend previous work on emotional development, adding information as to the role of emotional intensity for affective experience in different age groups. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Creating a Protective Shell for Reactive MoSi2 Particles in High‐Temperature Ceramics

Alumina encapsulated molybdenum silicide (MoSi₂) intermetallic particles were synthesized using a simple precipitation method followed by calcining at temperatures of 800°C–1000°C, to prevent the premature oxidation of MoSi₂ at high temperatures. The shell composition and the influence of the calcining temperature on microcapsule integrity were investigated by means of X‐ray photoelectron spectroscopy, X‐ray diffraction, scanning electron microscopy, and thermogravimetric analysis. The results demonstrate that the composition and the mechanical stability of the alumina shell can be tuned by the annealing temperature. After calcining at 800°C and 850°C the alumina shell remains intact. Calcining at higher temperature promotes the formation of mullite, which leads to cracking of the shell. However, when annealed at 1000°C for 24 h these cracks were filled with mullite and preserved the molybdenum silicide particles. Furthermore, the mechanical stability of the shell was improved by applying an intermediate calcining treatment at 450°C prior to the annealing process at 1000°C.     

Structure and Thermal Expansion of YSZ and La2Zr2O7 Above 1500°C from Neutron Diffraction on Levitated Samples

High‐temperature time‐of‐flight neutron diffraction experiments were performed on cubic yttria‐stabilized zirconia (YSZ, 10 mol% YO_1.5) and lanthanum zirconate (LZ) prepared by laser melting. Three spheroids of each composition were aerodynamically levitated and rotated in argon flow and heated with a CO₂ laser. Unit cell, positional and atomic displacement parameters were obtained by Rietveld analysis. Below ~1650°C the mean thermal expansion coefficient (TEC) for YSZ is higher than for LZ (13 ± 1 vs. 10.3 ± 0.6) × 10^?6/K. From ~1650°C to the onset of melting of LZ at ~2250°C, TEC for YSZ and LZ are similar and within (7 ± 2) × 10^?6/K. LZ retains the pyrochlore structure up to the melting temperature with Zr coordination becoming closer to perfectly octahedral. Congruently melting LZ is La deficient. The occurrence of thermal disordering of oxygen sublattice (Bredig transition) in defect fluorite structure was deduced from the rise in YSZ TEC to ~25 × 10^?6/K at 2350°C–2550°C with oxygen displacement parameters (U_iso) reaching 0.1 Å², similar to behavior observed in UO₂. Acquisition of powder‐like high‐temperature neutron diffraction data from solid‐levitated samples is feasible and possible improvements are outlined. This methodology should be applicable to a wide range of materials for high‐temperature applications.     

Do ‘green’ buildings have better indoor environments? New evidence

A post-occupancy evaluation (POE) of 12 green and 12 conventional office buildings across Canada and the northern United States was conducted. Occupants (N = 2545) completed an online questionnaire related to environmental satisfaction, job satisfaction and organizational commitment, health and well-being, environmental attitudes, and commuting. In each building on-site physical measurements at a sample of workstations (N= 974) were taken, including: thermal conditions, air quality, acoustics, lighting, workstation size, ceiling height, window access and shading, and surface finishes. Green buildings exhibited superior performance compared with similar conventional buildings. Better outcomes included: environmental satisfaction, satisfaction with thermal conditions, satisfaction with the view to the outside, aesthetic appearance, less disturbance from heating, ventilation and air-conditioning (HVAC) noise, workplace image, night-time sleep quality, mood, physical symptoms, and reduced number of airborne particulates. A variety of physical features led to improved occupant outcomes across all buildings, including: conditions associated with speech privacy, lower background noise levels, higher light levels, greater access to windows, conditions associated with thermal comfort, and fewer airborne particulates. Green building rating systems might benefit from further attention in several areas, including: credits related to acoustic performance, a greater focus on reducing airborne particulates, enhanced support for the interdisciplinary design process and development of POE protocols.

Il a été mené une évaluation après occupation (POE) de 12 immeubles de bureaux verts et 12 immeubles de bureaux classiques répartis à travers le Canada et le nord des Etats-Unis. Les occupants (N?=?2545) ont rempli un questionnaire en ligne portant sur la satisfaction environnementale, la satisfaction au travail et l'implication organisationnelle, la santé et le bien-être, les attitudes environnementales, et les trajets réguliers. Dans chaque immeuble, des mesures physiques in situ sur un échantillon de postes de travail (N?=?974) ont été effectuées, comprenant : les conditions thermiques, la qualité de l'air, l'acoustique, l'éclairage, la taille des postes de travail, la hauteur de plafond, l'accès aux fenêtres et leur occultation, et les finitions de surface. Les bâtiments verts ont affiché des performances supérieures par rapport aux bâtiments classiques similaires. De meilleurs résultats ont été obtenus concernant la satisfaction environnementale, la satisfaction à l'égard des conditions thermiques, la satisfaction à l'égard de la vue sur l'extérieur, l'aspect esthétique, la diminution des perturbations liées aux bruits provenant du chauffage, de la ventilation et de la climatisation (CVC), l'image du lieu de travail, la qualité du sommeil nocturne, l'humeur, les symptômes physiques, et la réduction du nombre de particules en suspension dans l'air. Différentes caractéristiques physiques ont conduit à une amélioration des résultats pour les occupants dans tous les immeubles, concernant notamment les conditions liées à la confidentialité des conversations, les niveaux inférieurs de bruit de fond, les niveaux de luminosité plus élevés, l'accès accru aux fenêtres, les conditions associées au confort thermique, et le nombre moindre de particules en suspension dans l'air. Les systèmes de notation des bâtiments verts pourraient bénéficier d'une plus grande attention apportée à plusieurs domaines, s'agissant en particulier des crédits relatifs aux performances acoustiques, d'un accent accru sur la réduction des particules en suspension dans l'air, d'un soutien renforcé en faveur du processus de conception interdisciplinaire et du développement de protocoles POE.

Mots clés: performances des bâtiments, bilan environnemental, bâtiments verts, environnement intérieur, Leadership in Energy and Environmental Design (LEED), satisfaction des occupants, évaluation après occupation     

Phenol decomposition in water cathode of DC atmospheric pressure discharge in air

We studied phenol decomposition in aqueous solution under the action of DC discharge at atmospheric pressure in air. The decomposition efficiency was 0.017 molecules per 100 eV. When the kinetics of forming destruction products was studied in detail, the peculiarities of air plasma action were revealed for the first time. Plasma action not only results in the formation of oxygen-containing products, which are usually formed under oxygen plasma action (hydroxyhenols, carboxylic acids, aldehydes), but also the formation of nitro phenols. The treatment is accompanied by hydrogen peroxide formation, a pH decrease, and nitric and nitrous acids formation. We also discussed the possible mechanism of the processes and the role of some active species in chemical transformations after determining some parameters of the discharge.     

Serum lipid analysis and isotopic enrichment is suggestive of greater lipogenesis in young long-term cannabis users: A secondary analysis of a case–control study

Cannabis is now legal in many countries and while numerous studies have reported on its impact on cognition and appetite regulation, none have examined fatty acid metabolism in young cannabis users. We conducted an exploratory analysis to evaluate cannabis impact on fatty acid metabolism in cannabis users (n = 21) and non-cannabis users (n = 16). Serum levels of some saturated and monounsaturated fatty acids, including palmitic, palmitoleic, and oleic acids were higher in cannabis users compared to nonusers. As palmitic acid can be derived from diet or lipogenesis from sugars, we evaluated lipogenesis using a de novo lipogenesis index (palmitate/linoleic acid) and carbon-specific isotope analysis, which allows for the determination of fatty acid ¹³C signature. The significantly higher de novo lipogenesis index in the cannabis users group along with a more enriched ¹³C signature of palmitic acid suggested an increase in lipogenesis. In addition, while serum glucose concentration did not differ between groups, pyruvate and lactate were lower in the cannabis user group, with pyruvate negatively correlating with palmitic acid. Furthermore, the endocannabinoid 2-arachidonoylglycerol was elevated in cannabis users and could contribute to lipogenesis by activating the cannabinoid receptor 1. Because palmitic acid has been suggested to increase inflammation, we measured peripheral cytokines and observed no changes in inflammatory cytokines. Finally, an anti-inflammatory metabolite of palmitic acid, palmitoylethanolamide was elevated in cannabis users. Our results suggest that lipogenic activity is increased in cannabis users; however, future studies, including prospective studies that control dietary intake are required.     

Synthetic Activity of Recombinant Whole Cell Biocatalysts Containing 2-Deoxy-D-ribose-5-phosphate Aldolase from Pectobacterium atrosepticum

In nature 2-deoxy-D-ribose-5-phosphate aldolase (DERA) catalyses the reversible formation of 2-deoxyribose 5-phosphate from D-glyceraldehyde 3-phosphate and acetaldehyde. In addition, this enzyme can use acetaldehyde as the sole substrate, resulting in a tandem aldol reaction, yielding 2,4,6-trideoxy-D-erythro-hexapyranose, which spontaneously cyclizes. This reaction is very useful for the synthesis of the side chain of statin-type drugs used to decrease cholesterol levels in blood. One of the main challenges in the use of DERA in industrial processes, where high substrate loads are needed to achieve the desired productivity, is its inactivation by high acetaldehyde concentration. In this work, the utility of different variants of Pectobacterium atrosepticum DERA (PaDERA) as whole cell biocatalysts to synthesize 2-deoxyribose 5-phosphate and 2,4,6-trideoxy-D-erythro-hexapyranose was analysed. Under optimized conditions, E. coli BL21 (PaDERA C-His AA C49M) whole cells yields 99 % of both products. Furthermore, this enzyme is able to tolerate 500 mM acetaldehyde in a whole-cell experiment which makes it suitable for industrial applications.     

Energetics and Structure of Polymer‐Derived Si–(B–)O–C Glasses: Effect of the Boron Content and Pyrolysis Temperature

The structure and properties of polymer‐derived Si–(B–)O–C glasses have been shown to be significantly influenced by the boron content and pyrolysis temperature. This work determined the impact of these two parameters on the thermodynamic stability of these glasses. High‐temperature oxide melt solution calorimetry was performed on a series of amorphous samples, with varying boron contents (0–7.7 at.%), obtained by pyrolysis of precursors made by a sol–gel technique. Thermodynamic analysis of the calorimetric results demonstrated that at a constant pyrolysis temperature, adding boron makes the materials energetically less stable. While the B‐containing glasses pyrolyzed at 1000°C were energetically less stable than the competitive crystalline components, increasing the pyrolysis temperature to 1200°C led to their enthalpic stability. ²⁹Si and ¹¹B MAS nuclear magnetic resonance (NMR) spectroscopy measurements on selected samples confirmed a decrease in the concentrations of mixed Si‐centered SO_iC_4?i and B‐centered BO_jC_3?j bonds at the expense of formation of SiO₄ and B(OSi)₃ species (indicating a tendency toward phase separation) when the boron content and pyrolysis temperature increased. In light of the findings from calorimetry and NMR spectroscopy, we propose a structure–energetic relationship in Si–(B–)O–C glasses.