206 research outputs found
Chemical reactivity of ultracold polar molecules: investigation of H + HCl and H + DCl collisions
Quantum scattering calculations are reported for the H+HCl(v,j=0) and
H+DCl(v,j=0) collisions for vibrational levels v=0-2 of the diatoms.
Calculations were performed for incident kinetic energies in the range 10-7 to
10-1 eV, for total angular momentum J=0 and s-wave scattering in the entrance
channel of the collisions. Cross sections and rate coefficients are
characterized by resonance structures due to quasibound states associated with
the formation of the H...HCl and H...DCl van der Waals complexes in the
incident channel. For the H+HCl(v,j=0) collision for v=1,2, reactive scattering
leading to H_2 formation is found to dominate over non-reactive vibrational
quenching in the ultracold regime. Vibrational excitation of HCl from v=0 to
v=2 increases the zero-temperature limiting rate coefficient by about 8 orders
of magnitude.Comment: 9 pages, 6 figures, submitted to Euro. Phys. J. topical issue on
"Ultracold Polar Molecules: Formation and Collisions
Structure, electrochemical properties and functionalization of amorphous CN films deposited by femtosecond pulsed laser ablation
Amorphous carbon nitride (a-C:N) material has attracted much attention in research and development. Recently, it has become a more promising electrode material than conventional carbon based electrodes in electrochemical and biosensor applications. Nitrogen containing amorphous carbon (a-C:N) thin films have been synthesized by femtosecond pulsed laser deposition (fs-PLD) coupled with plasma assistance through Direct Current (DC) bias power supply. During the deposition process, various nitrogen pressures (0 to 10 Pa) and DC bias (0 to ¿ 350 V) were used in order to explore a wide range of nitrogen content into the films. The structure and chemical composition of the films have been studied by using Raman spectroscopy, electron energy-loss spectroscopy (EELS) and high-resolution transmission electron microscopy (HRTEM). Increasing the nitrogen pressure or adding a DC bias induced an increase of the N content, up to 21 at.%. Nitrogen content increase induces a higher sp2 character of the film. However DC bias has been found to increase the film structural disorder, which was detrimental to the electrochemical properties. Indeed the electrochemical measurements, investigated by cyclic voltammetry (CV), demonstrated that a-C:N film with moderate nitrogen content (10 at.%) exhibited the best behavior, in terms of reversibility and electron transfer kinetics. Electrochemical grafting from diazonium salts was successfully achieved on this film, with a surface coverage of covalently bonded molecules close to the dense packed monolayer of ferrocene molecules. Such a film may be a promising electrode material in electrochemical detection of electroactive pollutants on bare film, and of biopathogen molecules after surface grafting of the specific affinity receptor.This work is produced with the financial support of the Future Program Lyon Saint-Etienne (PALSE) from the University of Lyon (ANR-11-IDEX-0007), under the “Investissements d'Avenir” program managed by the National Agency Research (ANR)
2009 pandemic influenza A(H1N1) virus in Scotland : geographically variable immunity in Spring 2010, following the winter outbreak
We determined the age- and location-specific seroprevalence of antibodies against 2009 pandemic influenza A(H1N1) virus in Scotland following the first two waves of infection. Serum samples collected following the winter outbreak were analysed by microneutralisation assay. The proportion of positive sera varied significantly between cities and, in the case of Inverness, between age groups (with younger adults more likely to be positive than older individuals). This study demonstrates that older people are no longer more likely to have antibodies against the virus than younger adults
Slowing and cooling molecules and neutral atoms by time-varying electric field gradients
A method of slowing, accelerating, cooling, and bunching molecules and
neutral atoms using time-varying electric field gradients is demonstrated with
cesium atoms in a fountain. The effects are measured and found to be in
agreement with calculation. Time-varying electric field gradient slowing and
cooling is applicable to atoms that have large dipole polarizabilities,
including atoms that are not amenable to laser slowing and cooling, to Rydberg
atoms, and to molecules, especially polar molecules with large electric dipole
moments. The possible applications of this method include slowing and cooling
thermal beams of atoms and molecules, launching cold atoms from a trap into a
fountain, and measuring atomic dipole polarizabilities.Comment: 13 pages, 10 figures. Scheduled for publication in Nov. 1 Phys. Rev.
Nano-Architecture of nitrogen-doped graphene films synthesized from a solid CN source
New synthesis routes to tailor graphene properties by controlling the concentration and chemical configuration of dopants show great promise. Herein we report the direct reproducible synthesis of 2-3% nitrogen-doped ‘few-layer’ graphene from a solid state nitrogen carbide a-C:N source synthesized by femtosecond pulsed laser ablation. Analytical investigations, including synchrotron facilities, made it possible to identify the configuration and chemistry of the nitrogen-doped graphene films. Auger mapping successfully quantified the 2D distribution of the number of graphene layers over the surface, and hence offers a new original way to probe the architecture of graphene sheets. The films mainly consist in a Bernal ABA stacking three-layer architecture, with a layer number distribution ranging from 2 to 6. Nitrogen doping affects the charge carrier distribution but has no significant effects on the number of lattice defects or disorders, compared to undoped graphene synthetized in similar conditions. Pyridinic, quaternary and pyrrolic nitrogen are the dominant chemical configurations, pyridinic N being preponderant at the scale of the film architecture. This work opens highly promising perspectives for the development of self-organized nitrogen-doped graphene materials, as synthetized from solid carbon nitride, with various functionalities, and for the characterization of 2D materials using a significant new methodology
Determinants of adherence to the mediterranean diet in Spanish children and adolescents: the PASOS Study
A progressive shift away from traditional healthy dietary patterns, such as the Mediterranean diet (MedDiet), has been observed in recent decades. The aim of this study was to assess determinants of optimal adherence to the MedDiet in Spanish children and adolescents. A cross-sectional analysis was included in the PASOS nationwide representative study in Spain. Participants were 3607 children and adolescents; 8–16 years old. Primary and secondary outcome measures of weight and height were measured. Adherence to the MedDiet, physical activity, and sedentary behavior in children and adolescents, as well as parental physical activity and dietary habits, were assessed. Optimal adherence to the MedDiet was observed in 45.5% of primary school students and 34.8% of secondary school students (OR: 0.65; 95%CI: 0.56–0.75). Optimal adherence to the MedDiet was higher in children/adolescents meeting daily recommended moderate and vigorous physical activity (OR: 2.39, 95%CI: 1.97–2.89) and in those meeting daily recommended screen time on week-days (OR: 2.05, 95%CI: 1.77–2.38) and weekends (OR: 1.76, 95%CI: 1.48–2.10). Participants with optimal adherence to the MedDiet were more likely to have mothers with a high-level education and high-tercile of SDQS, mothers who never smoked or were former smokers, and mothers who met the recommended physical activity and screen time. It can be concluded that a low prevalence of optimal adherence to the MedDiet was found among current Spanish children and adolescents. Optimal adherence to the MedDiet was associated with reaching the recommendations on physical activity and screen time, with the highest maternal educational level, and healthier maternal life-styles.The PASOS study was funded by Fundación PROBITAS and the Gasol Foundation. Additional funds were received from the Barça Foundation, Banco Santander, IFA, Vienna and the Fundación Deporte Joven (no references are applicable). J.A.T., C.B., M.M.G., and M.M.B. were funded by CIBEROBN (CB12/03/30038) of the Institute of Health Carlos III (ISCIII), and co-funded by the European Regional Development Fund
Trends in Adherence to the Mediterranean Diet in Spanish Children and Adolescents across Two Decades.
Unhealthy dietary habits determined during childhood may represent a risk factor to many of the chronic non-communicable diseases (NCDs) in adulthood. Mediterranean Diet (MD) adherence in children and adolescents (8–16 years) living in Spain was investigated using the KIDMED questionnaire in a comparative analysis of two cross-sectional nationwide representative studies: enKid (1998–2000, n = 1001) and PASOS (2019–2020, n = 3540). Taking into account the educational level of pupils, as well as the characteristics of the place of living, a significant association was found between a KIDMED score ≥ 8 (optimal MD adherence) and primary education as well as residency in an area of <50,000 inhabitants, while living in the southern regions was associated with non-optimal MD adherence (p < 0.001). Participants of the 2019–2020 study showed an increase in the consumption of dairy products (31.1% increase), pasta/rice (15.4% increase), olive oil (16.9% increase), and nuts (9.7% increase), as well as a decreased sweets and candies intake (12.6% reduction). In contrast, a significantly lower MD adherence was found when comparing the 2019–2020 (mean ± SE: 6.9 ± 0.04) and the 1998–2000 study (7.37 ± 0.08); p < 0.001), due to less consumption of fish (20.3% reduction), pulse (19.4% reduction), and fruits (14.9% reduction), and an increased intake of commercial goods/pastries or fast-food intake (both 19.4% increase). The lowest adherence was recorded for adolescents also in the most recent study, where 10.9% of them presented a KIDMED score ≤ 3. This study shows that eating habits are deteriorating among Spanish children and adolescents. Such findings point out the urgency of undertaking strong measures to promote the consumption of healthy, sustainable, and non-ultra-processed food, such as those available in an MD, not only at a scientific and academic level, but also at a governmental onePartial funding for open access charge: Universidad de Málag
Refining trait resilience: identifying engineering, ecological, and adaptive facets from extant measures of resilience
The current paper presents a new measure of trait resilience derived from three common
mechanisms identified in ecological theory: Engineering, Ecological and Adaptive (EEA)
resilience. Exploratory and confirmatory factor analyses of five existing resilience scales
suggest that the three trait resilience facets emerge, and can be reduced to a 12-item scale.
The conceptualization and value of EEA resilience within the wider trait and well-being psychology
is illustrated in terms of differing relationships with adaptive expressions of the traits
of the five-factor personality model and the contribution to well-being after controlling for
personality and coping, or over time. The current findings suggest that EEA resilience is a
useful and parsimonious model and measure of trait resilience that can readily be placed
within wider trait psychology and that is found to contribute to individual well-bein
Mechanisms of redundancy and specificity of the Aspergillus fumigatus Crh transglycosylases
Transglycosylases strengthen the fungal cell wall by forming a rigid network of crosslinks. Here, Fang et al. show that the five Crh transglycosylases of Aspergillus fumigatus are dispensable for cell wall integrity in vitro, and solve the crystal structure of Crh5 in complex with chitooligosaccharides
Quo vadis, cold molecules? - Editorial review
We give a snapshot of the rapidly developing field of ultracold polar
molecules abd walk the reader through the papers appearing in this topical
issue
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