61 research outputs found
Memorias inĂ©ditas de MarĂa Bashkirtseff
Copia digital. Valladolid : Junta de Castilla y LeĂłn. ConsejerĂa de Cultura y Turismo, 2012-201
Pulsed Electromagnetic Field Stimulates Cellular Proliferation in Human Intervertebral Disc Cells
âThe authors have no financial conflicts of interest. Purpose: The purpose of this study is to investigate the mechanism of cellular proliferation of electromagnetic field (EMF) on human intervertebral disc (IVD) cells. Materials and Methods: Human IVD cells were cultured three-dimensionally in alginate beads. EMF was exposed to IVD cells with 650 ÎȘ, 1.8 millitesla magnetic flux density, 60 Hz sinusoidal wave. Cultures were divided into a control and EMF group. Cytotoxicity, DNA synthesis and proteoglycan synthesis were measured by MTT assay, [ 3 H]-thymidine, and [ 35 S]-sulfate incorporation. To detect phenotypical expression, reverse transcription-polymerase chain reactions (RT-PCR) were performed for aggrecan, collagen type I, and type II mRNA expression. To assess action mechanism of EMF, IVD cells were exposed to EMF with N G-Monomethyl-L-arginine (NMMA) and acetylsalicylic acid (ASA). Results: There was no cytotoxicity in IVD cells with the EMF group in MTT assay. Cellular proliferation was observed in the EMF group (p < 0.05). There was no difference in newl
Vitamin C and infectious diseases
Non peer reviewe
Ultracold polar molecules : internal structure and optical control
Ce mĂ©moire sâinscrit dans le cadre des recherches sur les molĂ©cules ultra-froides, en forte expansion depuis plusieurs annĂ©es. Contrairement aux atomes, les molĂ©cules ne peuvent que trĂšs difficilement ĂȘtre refroidies par laser. Il est donc nĂ©cessaire dâexplorer des mĂ©thodes alternatives pour parvenir Ă la crĂ©ation de gaz molĂ©culaires ultra-froids. Ce travail thĂ©orique sâest focalisĂ© sur une classe particuliĂšre de molĂ©cules diatomiques hĂ©tĂ©ronuclĂ©aires, prĂ©sentant un moment dipolaire Ă©lectrique ou magnĂ©tique intrinsĂšque Ă lâorigine de leurs interactions mutuelles anisotropes.Sur la base de la connaissance prĂ©cise de la spectroscopie des molĂ©cules KRb et KCs (prĂ©sentant un moment dipolaire Ă©lectrique intrinsĂšque notable), combinĂ©e Ă des rĂ©sultats thĂ©oriques, nous avons modĂ©lisĂ© le refroidissement de leurs degrĂ©s de libertĂ© internes au moyen du passage adiabatique Raman stimulĂ© (STIRAP), processus laser conduisant les molĂ©cules dans leur Ă©tat fondamental absolu. Plusieurs schĂ©mas STIRAP ont Ă©tĂ© discutĂ©s et comparĂ©s entre eux du point de vue de leur efficacitĂ©.Nous avons ensuite Ă©tudiĂ© la molĂ©cule RbCa, dont la spectroscopie est encore inconnue. Cette espĂšce est caractĂ©risĂ©e par la prĂ©sence conjointe dâun moment dipolaire Ă©lectrique et magnĂ©tique permanent, qui prĂ©sente un fort intĂ©rĂȘt pour les possibilitĂ©s de contrĂŽle des interactions anisotropes quâils engendrent. Nous avons dĂ©terminĂ© la structure Ă©lectronique de RbCa par deux mĂ©thodes diffĂ©rentes de chimie quantique, permettant ainsi de qualifier la prĂ©cision des rĂ©sultats. Nous avons aussi proposĂ© un schĂ©ma de transitions laser conduisant Ă la formation de molĂ©cules froides de RbCa Ă partir des atomes sĂ©parĂ©s.La manipulation et le piĂ©geage de molĂ©cules repose sur la connaissance de leur rĂ©ponse Ă un champ Ă©lectromagnĂ©tique externe, caractĂ©risĂ©e par leur polarisabilitĂ© dipolaire dynamique. Les calculs de chimie quantique entrepris plus haut nous ayant permis dâaccĂ©der Ă des Ă©tats molĂ©culaires trĂšs excitĂ©s, nous avons dĂ©terminĂ© cette quantitĂ© pour toute une sĂ©rie de molĂ©cules diatomiques (dimĂšres alcalins, RbCa, RbSr,âŠ). Nous avons ainsi pu dĂ©terminer les paramĂštres optimaux pour le piĂ©geage laser de ces molĂ©cules.This thesis deals with ultracold molecules research, which interest has been growing for several years. Unlike atoms, laser-cooling molecules is very difficult. Alternative methods are necessary to be searched for in order to create ultracold molecular gases. This theoretical work focuses on a particular type of heteronuclear diatomic molecules, possessing an intrinsic electric or magnetic dipole moment, from which originates their mutual anisotropic interactions.Based on the precise knowledge of KRb and KCs molecules (possessing a significant intrinsic electric dipole moment) spectroscopy, combined with theoretical results, the cooling of their internal degrees of freedom using Stimulated Raman Adiabatic Passage (STIRAP), a laser process bringing molecules towards their absolute ground state, has been modelled. Several STIRAP schemes have been investigated and compared regarding their efficiency. The RbCa molecule has then been studied, which spectroscopy is still unknown. The ability of controlling the anisotropic interactions induced by the simultaneous presence of an electric and magnetic dipole moment provided by this species is a clear advantage. The electronic structure of RbCa has been computed with two methods, thus allowing to estimate the reliability of the results. A scheme of laser transitions bringing to the formation of cold RbCa molecules from separate atoms has been proposed.Manipulating and trapping molecules relies on the precise knowledge of their response to an external electromagnetic field, characterised by their dynamic dipolar polarisability. The quantum chemistry calculations mentioned earlier allowed us to compute high-lying excited states, dynamic polarisability has then been computed for a whole set of diatomic molecules (alkali dimers, RbCa, RbSr, âŠ). The optimal parameters for trapping those molecules has then been determined
Molécules polaires ultra-froides : structure électronique et contrÎle optique
This thesis deals with ultracold molecules research, which interest has been growing for several years. Unlike atoms, laser-cooling molecules is very difficult. Alternative methods are necessary to be searched for in order to create ultracold molecular gases. This theoretical work focuses on a particular type of heteronuclear diatomic molecules, possessing an intrinsic electric or magnetic dipole moment, from which originates their mutual anisotropic interactions.Based on the precise knowledge of KRb and KCs molecules (possessing a significant intrinsic electric dipole moment) spectroscopy, combined with theoretical results, the cooling of their internal degrees of freedom using Stimulated Raman Adiabatic Passage (STIRAP), a laser process bringing molecules towards their absolute ground state, has been modelled. Several STIRAP schemes have been investigated and compared regarding their efficiency. The RbCa molecule has then been studied, which spectroscopy is still unknown. The ability of controlling the anisotropic interactions induced by the simultaneous presence of an electric and magnetic dipole moment provided by this species is a clear advantage. The electronic structure of RbCa has been computed with two methods, thus allowing to estimate the reliability of the results. A scheme of laser transitions bringing to the formation of cold RbCa molecules from separate atoms has been proposed.Manipulating and trapping molecules relies on the precise knowledge of their response to an external electromagnetic field, characterised by their dynamic dipolar polarisability. The quantum chemistry calculations mentioned earlier allowed us to compute high-lying excited states, dynamic polarisability has then been computed for a whole set of diatomic molecules (alkali dimers, RbCa, RbSr, âŠ). The optimal parameters for trapping those molecules has then been determined.Ce mĂ©moire sâinscrit dans le cadre des recherches sur les molĂ©cules ultra-froides, en forte expansion depuis plusieurs annĂ©es. Contrairement aux atomes, les molĂ©cules ne peuvent que trĂšs difficilement ĂȘtre refroidies par laser. Il est donc nĂ©cessaire dâexplorer des mĂ©thodes alternatives pour parvenir Ă la crĂ©ation de gaz molĂ©culaires ultra-froids. Ce travail thĂ©orique sâest focalisĂ© sur une classe particuliĂšre de molĂ©cules diatomiques hĂ©tĂ©ronuclĂ©aires, prĂ©sentant un moment dipolaire Ă©lectrique ou magnĂ©tique intrinsĂšque Ă lâorigine de leurs interactions mutuelles anisotropes.Sur la base de la connaissance prĂ©cise de la spectroscopie des molĂ©cules KRb et KCs (prĂ©sentant un moment dipolaire Ă©lectrique intrinsĂšque notable), combinĂ©e Ă des rĂ©sultats thĂ©oriques, nous avons modĂ©lisĂ© le refroidissement de leurs degrĂ©s de libertĂ© internes au moyen du passage adiabatique Raman stimulĂ© (STIRAP), processus laser conduisant les molĂ©cules dans leur Ă©tat fondamental absolu. Plusieurs schĂ©mas STIRAP ont Ă©tĂ© discutĂ©s et comparĂ©s entre eux du point de vue de leur efficacitĂ©.Nous avons ensuite Ă©tudiĂ© la molĂ©cule RbCa, dont la spectroscopie est encore inconnue. Cette espĂšce est caractĂ©risĂ©e par la prĂ©sence conjointe dâun moment dipolaire Ă©lectrique et magnĂ©tique permanent, qui prĂ©sente un fort intĂ©rĂȘt pour les possibilitĂ©s de contrĂŽle des interactions anisotropes quâils engendrent. Nous avons dĂ©terminĂ© la structure Ă©lectronique de RbCa par deux mĂ©thodes diffĂ©rentes de chimie quantique, permettant ainsi de qualifier la prĂ©cision des rĂ©sultats. Nous avons aussi proposĂ© un schĂ©ma de transitions laser conduisant Ă la formation de molĂ©cules froides de RbCa Ă partir des atomes sĂ©parĂ©s.La manipulation et le piĂ©geage de molĂ©cules repose sur la connaissance de leur rĂ©ponse Ă un champ Ă©lectromagnĂ©tique externe, caractĂ©risĂ©e par leur polarisabilitĂ© dipolaire dynamique. Les calculs de chimie quantique entrepris plus haut nous ayant permis dâaccĂ©der Ă des Ă©tats molĂ©culaires trĂšs excitĂ©s, nous avons dĂ©terminĂ© cette quantitĂ© pour toute une sĂ©rie de molĂ©cules diatomiques (dimĂšres alcalins, RbCa, RbSr,âŠ). Nous avons ainsi pu dĂ©terminer les paramĂštres optimaux pour le piĂ©geage laser de ces molĂ©cules
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