Pressure dependence of raman modes in double wall carbon nanotubes filled with 1D tellurium

The preparation of highly anisotropic one-dimensional (1D) structures confined into carbon nanotubes (CNTs) in general is a key objective in nanoscience. In this work, capillary effect was used to fill double wall carbon nanotubes (DWCNTs) with trigonal Tellurium. The samples are characterized by high resolution transmission electronic microscopy and Raman spectroscopy. In order to investigate their structural stability and unravel the differences induced by intershell interactions, unpolarized Raman spectra of radial and tangential modes of DWCNTs filled with 1D nanocrystalline Te excited with 514 nm were studied at room temperature and high pressure. Up to 11 GPa we found a pressure coefficient of 3.7 cm−1 GPa−1 for the internal tube and 7 cm−1 GPa−1 for the external tube. In addition, the tangential band of the external and internal tubes broaden and decrease in amplitude. All findings lead to the conclusion that the outer tube acts as a protection shield for the inner tube (at least up 11 GPa). No pressure-induced structural phase transition was observed in the studied range

Trigonal field acting at the Cr3+ 2 E states in ruby from magneto-optical measurements under high pressure

Magneto-optical measurements on ruby under high-pressure conditions provided direct determination of the trigonal crystal field acting at the t2g orbitals of Cr3+ in Al2O3 CrO6 and its dependence with pressure. The correlation study between the measured trigonal splitting and the trigonal distortion at the Al3+-substituted site indicates that the trigonal splitting increases with pressure whereas the trigonal distortion slightly reduces. The result is interpreted in terms of an enhancement of the electron-lattice coupling due to trigonal distortion upon reduction in the Al-O bond distance, i.e., the Cr-O bond distance R. The observed variations can be explained on the basis of empirical R dependence of the trigonal crystal field as VtrR?n with n=6. It is shown that this exponent does not change when we consider the pressure variation of the local structure around Cr3+ obtained from ab initio calculations. By the way, we also demonstrate that a methanol-ethanol mixture is a good pressure transmitting medium at cryogenic temperaturesFinancial support from the Spanish Ministerio de Ciencia e Innovación Project No. MAT2008-06873-C02-01, MALTA INGENIO-CONSOLIDER 2010 Grant No. CDS2007-0045, and EuroMagnet II FP7 program are acknowledged

Electronic structure of indium selenide probed by magnetoabsorption spectroscopy under high pressure

We report on an investigation of the peculiar electronic structure of the layered semiconductor InSe by magneto-optical experiments under high pressure up to 5 GPa. Magneto-absorption spectroscopy is performed under pulsed magnetic field up to 53 T using a specific setup. Excitonic magnetofingerprints and high-field oscillatory magnetoabsorption yield significant details on the band structure. In addition, the application of an external pressure unveils phenomena that confirm the specific k·p model proposed for this compound on the basis of earlier measurements

Anharmonic effects in ZnO optical phonons probed by Raman spectroscopy

We report Raman spectroscopy measurements on ZnO crystals grown by the vapor transport method and annealed. Vacuum annealing is found to yield single crystals with ultra low density of defects. We focus on the optical E2 phonon linewidth temperature dependence in the 10?500 K range. The linewidth decrease at low temperature is analyzed and discussed in the light of anharmonic up- and down-conversion processes, unveiling strongly different behaviors for the two E2 phonons

An update of the Worldwide Integrated Assessment (WIA) on systemic insecticides. Part 2: impacts on organisms and ecosystems

New information on the lethal and sublethal effects of neonicotinoids and fipronil on organisms is presented in this review, complementing the previous WIA in 2015. The high toxicity of these systemic insecticides to invertebrates has been confirmed and expanded to include more species and compounds. Most of the recent research has focused on bees and the sublethal and ecological impacts these insecticides have on pollinators. Toxic effects on other invertebrate taxa also covered predatory and parasitoid natural enemies and aquatic arthropods. Little, while not much new information has been gathered on soil organisms. The impact on marine coastal ecosystems is still largely uncharted. The chronic lethality of neonicotinoids to insects and crustaceans, and the strengthened evidence that these chemicals also impair the immune system and reproduction, highlights the dangers of this particular insecticidal classneonicotinoids and fipronil. , withContinued large scale – mostly prophylactic – use of these persistent organochlorine pesticides has the potential to greatly decreasecompletely eliminate populations of arthropods in both terrestrial and aquatic environments. Sublethal effects on fish, reptiles, frogs, birds and mammals are also reported, showing a better understanding of the mechanisms of toxicity of these insecticides in vertebrates, and their deleterious impacts on growth, reproduction and neurobehaviour of most of the species tested. This review concludes with a summary of impacts on the ecosystem services and functioning, particularly on pollination, soil biota and aquatic invertebrate communities, thus reinforcing the previous WIA conclusions (van der Sluijs et al. 2015)

ARIA 2016 : Care pathways implementing emerging technologies for predictive medicine in rhinitis and asthma across the life cycle

The Allergic Rhinitis and its Impact on Asthma (ARIA) initiative commenced during a World Health Organization workshop in 1999. The initial goals were (1) to propose a new allergic rhinitis classification, (2) to promote the concept of multi-morbidity in asthma and rhinitis and (3) to develop guidelines with all stakeholders that could be used globally for all countries and populations. ARIA-disseminated and implemented in over 70 countries globally-is now focusing on the implementation of emerging technologies for individualized and predictive medicine. MASK [MACVIA (Contre les Maladies Chroniques pour un Vieillissement Actif)-ARIA Sentinel NetworK] uses mobile technology to develop care pathways for the management of rhinitis and asthma by a multi-disciplinary group and by patients themselves. An app (Android and iOS) is available in 20 countries and 15 languages. It uses a visual analogue scale to assess symptom control and work productivity as well as a clinical decision support system. It is associated with an inter-operable tablet for physicians and other health care professionals. The scaling up strategy uses the recommendations of the European Innovation Partnership on Active and Healthy Ageing. The aim of the novel ARIA approach is to provide an active and healthy life to rhinitis sufferers, whatever their age, sex or socio-economic status, in order to reduce health and social inequalities incurred by the disease.Peer reviewe

Simulation statistique de la nucléation homogène liquide-cristal de petites molécules

La maîtrise de la cristallisation et du polymorphisme des médicaments revêt une grande importance pour l'industrie pharmaceutique. Les mécanismes microscopiques gouvernant la nucléation, difficiles à explorer expérimentalement, sont encore mal connus. Récemment, de nouvelles techniques de simulation moléculaire, basées sur des échantillonnages configurationnels biaisés, ont permis de simuler la nucléation homogène de fluides atomiques. Dans cette thèse, nous avons adapté et appliqué ces méthodes à la nucléation homogène de petites molécules : le diazote et le dioxyde de carbone. Nous avons ainsi montré que i) les premiers germes cristallins formés lors de la nucléation du diazote possèdent, en accord avec la règle d'Ostwald, un arrangement cubique faces centrées métastable, puis se réorganisent en une forme hexagonale compacte stable; ii) la nucléation du dioxyde de carbone conduit directement à la formation de la phase stable cubique faces centrées ordonnée orientationnellement.Controlling the crystallization and polymorphism of drugs is of great interest for the pharmaceutical industry. The microscopic mechanisms governing nucleation which are difficult to investigate experimentally, are far from being well undestood. Recently, new molecular simulation techniques, based on a biased sampling of configurational space, have emerged. These techniques have successfully been used to investigate homogeneous nucleation in atomic liquids. In this thesis, we used these methods in order to simulate the nucleation of molecular nitrogen and carbon dioxide. We have shown that i) following Ostwald's step rule, the first crystalline nuclei formed in liquid nitrogen possess a metastable face centred cubic structure which later evolve to the stable hexagonal compact phase; ii) in the case of carbon dioxide, nucleation proceeds directly to the stable orientationally ordered face centred cubic phase.NANCY1-SCD Sciences & Techniques (545782101) / SudocSudocFranceF

La fécondation in vitro : une technique pour palier à l'infertilité des couples en France

REIMS-BU Santé (514542104) / SudocSudocFranceF

L'asthme et la pollution atmosphérique en milieu urbain (dénombrement des urgences pédiatriques à Reims lors des pcs de pollution)

REIMS-BU Santé (514542104) / SudocSudocFranceF

Les désordres endocriniens consécutifs à des activités en horaires décalés

REIMS-BU Santé (514542104) / SudocSudocFranceF