Search results for "molécula"
showing 9 items of 109 documents
Chiral gamma-lactones from Fusarium poae: enentiomeric ratios and sensory differentiation of cis-6-gamma-dodecenolactone enantiomers
1991
Chiral gamma-lactones from Fusarium poae: enentiomeric ratios and sensory differentiation of cis-6-gamma-dodecenolactone enantiomers
Three-dimensional bimetallic octacyanidometalates $[M^{IV}{(\mu-CN)_{4}Mn^{II}(H_{2}O)_2}_2 \cdot 4H_{2}O]_{n}$ (M=Nb,Mo,W) : synthesis, single-cryst…
2008
Abstract We report the synthesis, the single-crystal X-ray crystallographic structures and the magnetic properties of three new isostructural cyanido-bridged networks: [M IV {(μ-CN) 4 Mn II (H 2 O) 2 } 2 ·4H 2 O] n [M IV = Nb IV ( 1 ), Mo IV ( 2 ), W IV ( 3 )]. For compound 1 , the magnetic properties reveal a ferrimagnetic phase below 50 K. In contrast, compounds 2 and 3 show a paramagnetic behaviour with no magnetic ordering down to 2 K. The only electronic difference between the two kinds of compounds is the presence of two paired electrons on Mo IV ( 2 ) and W IV ( 3 ) (d 2 electronic configuration, S = 0) with no possible exchange interactions with Mn II ions (d 5 electronic configur…
Estudio de la acción proinflamatoria de Angiotensina II y su posible modulación. Papel de Angiotensina II en disfunciones endoteliales.
2002
La acumulación leucocitaria es una característica de los primeros estadios de la lesión aterosclerótica, de infarto agudo de miocardio y de enfermedades renales de diversa etiología. Receptores para Angiotensina-II (Ang-II) han sido hallados en monocitos y Ang-II puede promover la activación y adhesión de estas células. Este proceso podría desencadenar o perpetuar el daño endotelial asociado a aterosclerosis e hipertensión. Los resultados de nuestro estudio demuestran que Ang-II, a dosis subvasoconstrictoras y fisiológicas, presenta propiedades proinflamatorias in vivo a nivel agudo; en concreto, produce acumulación leucocitaria en vénulas de la microcirculación mesentérica de la rata a tra…
Sur la piste des matériaux organiques grâce à la spectrométrie de masse
2018
Identifying the organic materials present, establishing their origin and degree of preservation, understanding their manufacturing process and their use, all of which require interdisciplinary studies involving closely specialists in materials and human sciences. In this very specific context, mass spectrometry has become a key tool to improve knowledge of past civilizations but also to better preserve and restore the discrete remains of archaeomaterials. The identification of diagnostic molecular markers of natural substances is now a recognized strategy for characterizing amorphous organic materials (fats, beeswaxes, vegetable substances such as resins and tars). New advances have also ma…
Alignment of linear molecules by short duration laser pulses
2005
Alignment of linear molecules is efficiently induced by strong linearly polarized laser pulses. In the case of short pulses with respect to molecular rotation, periodic alignment appears in field-free conditions after the extinction of the field. This manuscript presents three techniques where the value of allows to quantify alignment without molecular dissociation nor additional alignment. They use a weak time-delayed probe pulse which experiences the optical properties of an aligned sample and shows modification of its characteristics. The first of them measures a depolarization due to the birefringence of the sample. The second one is based on the defocusing produced by the spatial distr…
Applications of Quantum Chemistry in Spectroscopy: Molecules, Complexes of Van der Waals, trapped Molecules
2009
I described in this memory my activities as a researcher at Tomsk well before 2003, in succession to the State University of Tomsk in the Faculty of Physics, Institute of Physics of Siberia, and the Institute of 'Atmospheric Optics, in France since then, mostly at the University of Bourgogne (ICB), but also at the University of Lille I (PhLAM) and the University of Marne-la-Vallée (LCT). Part of my work has been dedicated to the evaluation by calculating ab initio of rovibrational constants for quasi-spherical molecules. The centrifugal distortion constants and the dipole moment of the molecule SO2F2 were calculated to validate the tensor theory and interpreter the spectrum. I twas shown th…
Genome degeneration and adaptation in a nascent stage of symbiosis
2014
Symbiotic associations between animals and microbes are ubiquitous in nature, with an estimated 15% of all insect species harboring intracellular bacterial symbionts. Most bacterial symbionts share many genomic features including small genomes, nucleotide composition bias, high coding density, and a paucity of mobile DNA, consistent with long-term host association. In this study, we focus on the early stages of genome degeneration in a recently derived insect-bacterial mutualistic intracellular association. We present the complete genome sequence and annotation of Sitophilus oryzae primary endosymbiont (SOPE). We also present the finished genome sequence and annotation of strain HS, a close…
FORMATION OF MOLECULES IN ULTRACOLD ATOMIC GASES VIA QUASI-RESONANT FIELDS
2010
we study the nonlinear mean-field dynamics of diatomic molecule formation at coherent photo- and magneto-association of ultracold atoms focusing on the case when the system is initially in the all-atomic state. We show that in the limit of strongly nonlinear interaction between an ultra-cold atomic-molecular system and a quasi-resonant electromagnetic field, the molecule formation process, depending on the characteristics of the associating field, may evolve according two different scenarios, namely, weak- and strong-oscillatory regimes. In the first case the number of molecules increases without pronounced oscillations of atom-molecule populations, while in the second case high-amplitude R…
Nuevos materiales moleculares multifuncionales conmutables con transición de espín
2022
Este trabajo de Tesis Doctoral se centra en la síntesis y caracterización de nuevos materiales moleculares conmutables basados en FeII, los cuales presentan el fenómeno de transición de espín (spin crossover, SCO). El objetivo principal de esta tesis doctoral ha sido el diseño y estudio de nuevos materiales multifuncionales de FeII que combinan el comportamiento SCO con otra propiedad físico-química de interés. La estrecha interrelación entre el fenómeno SCO y dicha propiedad ha sido seguida y estudiada por estudios magnéticos, cristalográficos y calorimétricos, entre otros. El capítulo 1 de esta tesis describe los conceptos teóricos más importantes del fenómeno SCO, donde los centros SCO e…