Search results for "High-pressure"
showing 10 items of 63 documents
Phase behaviour of Ag2CrO4 under compression: Structural, vibrational, and optical properties
2013
We have performed an experimental study of the crystal structure, lattice dynamics, and optical properties of silver chromate (Ag2CrO4) at ambient temperature and high pressures. In particular, the crystal structure, Raman-active phonons, and electronic band gap have been accurately determined. When the initial orthorhombic Pnma Ag2CrO4 structure (phase I) is compressed up to 4.5 GPa, a previously undetected phase (phase II) has been observed with a 0.95% volume collapse. The structure of phase II can be indexed to a similar orthorhombic cell as phase I, and the transition can be considered to be an isostructural transition. This collapse is mainly due to the drastic contraction of the a ax…
Halogen...halogen interactions in pressure-frozen ortho- and meta-dichlorobenzene isomers.
2007
Isomers 1,2-dichlorobenzene (o-DCB) and 1,3-dichlorobenzene (m-DCB) were high-pressure frozen in-situ in a Merrill–Bassett diamond–anvil cell and their structures determined at room temperature and at 0.18 (5) GPa for o-DCB, and 0.17 (5) GPa for m-DCB by single-crystal X-ray diffraction. The patterns of halogen...halogen intermolecular interactions in these structures can be considered to be the main cohesive forces responsible for the molecular arrangements in these crystals. The molecular packing of dichlorobenzene isomers, including three polymorphs of 1,4-dichlorobenzene (p-DCB), have been compared and relations between their molecular symmetry, packing arrangements, intermolecular inte…
Local tunneling study of three-dimensional order parameter in the pi band of Al-doped MgB2 single crystals
2007
We have performed local tunneling spectroscopy on high quality Mg$_{1-x}$Al$_x$B$_2$ single crystals by means of Variable Temperature Scanning Tunneling Spectroscopy (STS) in magnetic field up to 3 Tesla. Single gap conductance spectra due to c-axis tunneling were extensively measured, probing different amplitudes of the three-dimensional $\Delta_\pi$ as a function of Al content. Temperature and magnetic field dependences of the conductance spectra were studied in S-I-N configuration: the effect of the doping resulted in a monotonous reduction of the locally measured $T_C$ down to 24K for x=0.2. On the other hand, we have found that the gap amplitude shows a maximum value $\Delta_\pi= 2.3$ …
Origin of Pressure-Induced Metallization in Cu 3 N: An X-ray Absorption Spectroscopy Study
2018
The authors are grateful to Professor Alain Polian for providing the NDAC cell.
Optimisation des techniques de chimiothérapie intracavitaire
2013
Introduction. In order to achieve a good effect, chemotherapy drugs need to penetrate into the peritoneal (HIPEC) or pleural tissue. Hyperthermia and high-pressure may enhance this penetration. The aim of this study was to evaluate their peritoneal effect and to establish the best technique to it. A feasibility study of an intrapleural high-pressure was an essential step to export these effects to the thoracic space. Methods. Four groups of pigs underwent an open HIPEC with a constant concentration (150 mg/l) of oxaliplatin during 30 minutes either in normothermia, or in hyperthermia (42-43°C); and either with atmospheric pressure or with high-pressure (25 cmH2O). Two more groups underwent …
Pressure-Induced Polymerization of Polycyclic Arene-Perfluoroarene Cocrystals: Single Crystal X-ray Diffraction Studies, Reaction Kinetics, and Desig…
2020
Pressure-induced polymerization of aromatic compounds leads to novel materials containing sp3 carbon-bonded networks. The choice of the molecular species and the control of their arrangement in the crystal structures via intermolecular interactions, such as the arene–perfluoroarene interaction, can enable the design of target polymers. We have investigated the crystal structure compression and pressure-induced polymerization reaction kinetics of two polycyclic 1:1 arene–perfluoroarene cocrystals, naphthalene/octafluoronaphthalene (NOFN) and anthracene/octafluoronaphthalene (AOFN), up to 25 and 30 GPa, respectively, using single-crystal synchrotron X-ray diffraction, infrared spectroscopy, a…
Low energy calibration, continuous monitoring, and background studies for the NEXT-White detector at the LSC
2021
Los neutrinos han sido una puerta a grandes cambios en los paradigmas del entendimiento de la naturaleza, y aún tienen preguntas que responder en las próximas décadas. El descubrimiento de la oscilación de neutrinos implica que éstos son partículas con masa. Esta masa abre la cuestión de su origen, es decir, si son fermiones de Dirac o de Majorana. La potencial naturaleza de Majorana puede arrojar luz en temas abiertos como la baja escala de masas de los neutrinos con respecto a los demás fermiones, así como la asimetría entre materia y antimateria observada actualmente en el universo. De entre todas las posibles formas de discernir la naturaleza última de los neutrinos, la más madura y des…
Effect of processing and food matrix on calcium and phosphorous bioavailability from milk-based fruit beverages in Caco-2 cells
2011
9 páginas, 4 figuras, 4 tablas.-- et al.
Pigments and their solubility in and extractability by supercritical CO2 - I: the case of curcumin
2000
A specially designed high-pressure cell was used simultaneously as extractor/autoclave and photometric cell in a Perkin Elmer Lambda 5 spectrophotometer. Based on this cell, a simple method was developed to determine the extractability of pigments by pure and by modified supercritical (sc) CO2. The method is demonstrated with curcumin from turmeric. With sc CO2 modified by 10% ethanol, the extraction yield for curcumin from two commercial finely ground dry turmeric samples was about 100%, measured by reference to the (complete) extraction of samples of the same charge with pure ethanol under standard conditions. Extractable curcumin content was from 1.8 to 2.5%, with three samples of turmer…
Cannabinoid 1/2 Receptor Activation Induces Strain-Dependent Behavioral and Neurochemical Changes in Genetic Absence Epilepsy Rats From Strasbourg an…
2022
Childhood absence epilepsy (CAE) is characterized by absence seizures, which are episodes of lack of consciousness accompanied by electrographic spike-wave discharges. About 60% of children and adolescents with absence seizures are affected by major neuropsychological comorbidities, including anxiety. Endocannabinoids and monoamines are likely involved in the pathophysiology of these CAE psychiatric comorbidities. Here, we show that the synthetic cannabinoid receptor type 1/2 (CB1/2R) agonist WIN 55,212-2 (2 mg/kg) has a strain-dependent effect on anxiety-like and motor behavior when assess in the hole board test and cerebral monoaminergic levels in Genetic Absence Epilepsy Rats from Strasb…