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Sample records for remodelage ventriculaire gauche

  1. Simultaneous gauche and anomeric effects in α-substituted sulfoxides.

    Science.gov (United States)

    Freitas, Matheus P

    2012-09-07

    α-Substituted sulfoxides can experience both gauche and anomeric effects, since these compounds have the geometric requirements and strong electron donor and acceptor orbitals which are essential to make operative the hyperconjugative nature of these effects. Indeed, the title effects were calculated to take place for 1,3-oxathiane 3-oxide in polar solution, where dipolar effects are absent or at least minimized, while only the gauche effect is present in 2-fluorothiane 1-oxide. Since the fluorine atom is a suitable probe for structural analysis using NMR, the (1)J(CF) dependence on the rotation around the F-C-S═O dihedral angle of (fluoromethyl)methyl sulfoxide was evaluated; differently from 1,2-difluoroethane and fluoro(methoxy)methane, this coupling constant is at least not exclusively dependent on dipolar interactions (or on hyperconjugation). Because of the nonmonotonic behavior of the (1)J(CF) rotational profile, this coupling constant does not appear to be of significant diagnostic value for probing the conformations of α-fluoro sulfoxides.

  2. Can acyclic conformational control be achieved via a sulfur-fluorine gauche effect?

    Science.gov (United States)

    Thiehoff, C; Holland, M C; Daniliuc, C; Houk, K N; Gilmour, R

    2015-06-01

    The gauche conformation of the 1,2-difluoroethane motif is known to involve stabilising hyperconjugative interactions between donor (bonding, σ C-H ) and acceptor (antibonding, σ *C-F) orbitals. This model rationalises the generic conformational preference of F-C β -C α -X systems ( φ FCCX ≈ 60°), where X is an electron deficient substituent containing a Period 2 atom. Little is known about the corresponding Period 3 systems, such as sulfur and phosphorus, where multiple oxidation states are possible. Conformational analyses of β-fluorosulfides, -sulfoxides and -sulfones are disclosed here, thus extending the scope of the fluorine gauche effect to the 3rd Period (F-C-C-S(O) n ; φ FCCS ≈ 60°). Synergy between experiment and computation has revealed that the gauche effect is only pronounced in structures bearing an electropositive vicinal sulfur atom (S + -O - , SO 2 ).

  3. The effect of gauche molecular conformations on the phase diagram of a Langmuir monolayer

    NARCIS (Netherlands)

    Zangi, R; Rice, SA

    2003-01-01

    Experimental and simulation studies have shown that the gauche conformational degrees of freedom of long-chain amphiphile molecules assembled in a dense Langmuir monolayer play an important role in determining the structures of the several phases that the monolayer supports. Nevertheless, for

  4. Myxome géant de l'oreillette gauche appendu à la valve mitrale ...

    African Journals Online (AJOL)

    Nous rapportons le cas d'un myxome de l'oreillette gauche chez un patient âgé de 28 ans, reçu en consultation externe pour douleur précordiale à l'effort et lipothymie. L'échocardiographie a permis de poser le diagnostic de myxome géant hyper mobile avec impact hémodynamique. La prise en charge a été limite à cause ...

  5. On the origin of the gauche effect. A quantum chemical study of 1,2-difluoroethane

    Science.gov (United States)

    Engkvist, O.; Karlström, G.; Widmark, P.-O.

    1997-01-01

    The conformational equilibrium of 1,2-difluoroethane has been investigated using ab initio quantum chemical calculations at the SCF, MP2 and CCSD(T) levels, with ANO basis sets. The relative stability of the gauche-conformation of 1,2-difluoroethane is found to be a consequence of the nodal structure of the singly occupied orbital in the CFH 2 radical. It is also shown that the nodal structure of the singly occupied orbitals in the CFH biradical can explain the stability of the cis conformation of 1,2-difluoroethene.

  6. Gauche effect in 1,2-difluoroethane. Hyperconjugation, bent bonds, steric repulsion.

    Science.gov (United States)

    Goodman, Lionel; Gu, Hongbing; Pophristic, Vojislava

    2005-02-17

    Natural bond orbital deletion calculations show that whereas the gauche preference arises from vicinal hyperconjugative interaction between anti C-H bonds and C-F* antibonds, the cis C-H/C-F* interactions are substantial (approximately 25% of the anti interaction). The established significantly >60 degrees FCCF dihedral angle for the equilibrium conformer can then be rationalized in terms of the hyperconjugation model alone by taking into account both anti interactions that maximize near 60 degrees and the smaller cis interactions that maximize at a much larger dihedral angle. This explanation does not invoke repulsive forces to rationalize the 72 degrees equilibrium conformer angle. The relative minimum energy for the trans conformer is the consequence of a balance between decreasing hyperconjugative stabilization and decreasing steric destabilization as the FCCF torsional angle approaches 180 degrees . The torsional coordinate is predicted to be strongly contaminated by CCF bending, with the result that approximately half of the trans --> gauche stabilization energy stems from mode coupling.

  7. Fluorine Gauche Effect Explained by Electrostatic Polarization Instead of Hyperconjugation: An Interacting Quantum Atoms (IQA) and Relative Energy Gradient (REG) Study.

    Science.gov (United States)

    Thacker, Joseph C R; Popelier, Paul L A

    2018-02-08

    We present an interacting quantum atoms (IQA) study of the gauche effect by comparing 1,2-difluoroethane, 1,2-dichloroethane, and three conformers of 1,2,3,4,5,6-hexafluorocyclohexane. In the 1,2-difluoroethane, the gauche effect is observed in that the gauche conformation is more stable than the anti, whereas in 1,2-dichloroethane the opposite is true. The analysis performed here is exhaustive and unbiased thanks to using the recently introduced relative energy gradient (REG) method [ Thacker , J. C. R. ; Popelier , P. L. A. Theor. Chem. Acc . 2017 , 136 , 86 ], as implemented in the in-house program ANANKE. We challenge the common explanation that hyperconjugation is responsible for the gauche stability in 1,2-difluoroethane and instead present electrostatics as the cause of gauche stability. Our explanation of the gauche effect is also is seen in other molecules displaying local gauche conformations, such as the recently synthesized "all-cis" hexafluorocyclohexane and its conformers where all the fluorine atoms are in the equatorial positions. Using our extension of the traditional IQA methodology that allows for the partitioning of electrostatic terms into polarization and charge transfer, we propose that the cause of gauche stability is 1,3 C···F electrostatic polarization interactions. In other words, if a number of fluorine atoms are aligned, then the stability due to polarization of nearby carbon atoms is increased.

  8. Transition State Gauche Effects Control the Torquoselectivities of the Electrocyclizations of Chiral 1-Azatrienes.

    Science.gov (United States)

    Patel, Ashay; Vella, Joseph R; Ma, Zhi-Xiong; Hsung, R P; Houk, K N

    2015-12-04

    Hsung et al. have reported a series of torquoselective electrocyclizations of chiral 1-azahexa-1E,3Z,5E-trienes that yield functionalized dihydropyridines. To understand the origins of the torquoselectivities of these azaelectrocyclizations, we modeled these electrocyclic ring closures using the M06-2X density functional. A new stereochemical model that rationalizes the observed 1,2 stereoinduction emerges from these computations. This model is an improvement and generalization of the "inside-alkoxy" model used to rationalize stereoselectivities of the 1,3-dipolar cycloaddition of chiral allyl ethers and emphasizes a stabilizing hyperconjugative effect, which we have termed a transition state gauche effect. This stereoelectronic effect controls the conformational preferences at the electrocyclization transition states, and only in one of the allowed disrotatory electrocyclization transition states is the ideal stereoelectronic arrangement achieved without the introduction of a steric clash. Computational experiments confirm the role of this effect as a stereodeterminant since substrates with electropositive groups and electronegative groups have different conformational preferences at the transition state and undergo ring closure with divergent stereochemical outcomes. This predicted reversal of stereoselectivity for the ring closures of several silyl substituted azatrienes have been demonstrated experimentally.

  9. The Fluorine Gauche Effect Explained by Electrostatic Polarization Instead of Hyperconjugation: An Interacting Quantum Atoms (IQA) and Relative Energy Gradient (REG) Study

    OpenAIRE

    Thacker, Joseph; Popelier, Paul

    2018-01-01

    We present an interacting quantum atoms (IQA) study of the gauche effect by comparing 1,2-difluoroethane, 1,2-dichloroethane, and three conformers of 1,2,3,4,5,6-hexafluorocyclohexane. In the 1,2-difluoroethane, the gauche effect is observed in that the gauche conformation is more stable than the anti, whereas in 1,2-dichloroethane the opposite is true. The analysis performed here is exhaustive and unbiased thanks to using the recently introduced relative energy gradient (REG) method [Thacker...

  10. O lirismo gauche de Afonso Henriques Neto: reflexões sobre a poesia brasileira contemporânea

    Directory of Open Access Journals (Sweden)

    Marleide Anchieta de Lima

    2014-06-01

    Full Text Available This article intends to analyse the lyrical peculiarities in the poetry of Afonso Henriques Neto, placing them into the current Brazilian literary panorama. In addiction, it discusses the poet's gauche writing as a verbal-visual displacement observed in his formal and thematic imprecisions, in the problematization of his poetic heritage and in his relation with the "marginal" generation, with the beatniks and with the poets of the French modernism.

  11. Linking structure and vibrational mode coupling using high-resolution infrared spectroscopy: A comparison of gauche and trans 1-chloro-2-fluoroethane

    Science.gov (United States)

    Miller, C. Cameron; Stone, Stephen C.; Philips, Laura A.

    1995-01-01

    The high-resolution infrared spectrum of 1-chloro-2-fluoroethane in a molecular beam was collected over the 2975-2994 cm-1 spectral region. The spectral region of 2975-2981 cm-1 contains a symmetric C-H stretching vibrational band of the gauche conformer containing the 35Cl isotope. The spectral region of 2985-2994 cm-1 contains three vibrational bands of the trans conformer. Two of the three bands are assigned as an antisymmetric C-H stretch of each of the two different chlorine isotopes. The third band is assigned as a symmetric C-H stretch of the 35Cl isotope. The gauche conformer of 1-chloro-2-fluoroethane showed doublet patterns similar to those previously observed in 1,2-difluoroethane. The model for 1,2-difluoroethane is further refined in the present work. These refinements suggest that the coupling dark state in 1,2-difluoroethane is composed of 1 quantum C-H bend, 1 quantum C-C stretch, and 12 quanta of torsion. For 1-chloro-2-fluoroethane the dark state could not be identified due to a small data set. The trans conformer of 1-chloro-2-fluoroethane showed no evidence of mode coupling in the three vibrational bands. Including 2-fluoroethanol in this series of molecules, the extent of vibrational mode coupling did not correlate with the density of states available for coupling. Therefore, density of states alone is insufficient to explain the observed trend. A correlation was observed between the degree of intramolecular interaction and vibrational mode coupling.

  12. Dislocations à gauche et antépositions de compléments en anglais : formes, fonctionnalités et insertion en discours

    Directory of Open Access Journals (Sweden)

    Laure Gardelle

    2010-12-01

    Full Text Available Parmi les énoncés non canoniques de l’anglais, deux procédés permettent de placer à l’initiale un constituant dont le référent est un participant au procès : la dislocation à gauche et l’antéposition. Certaines études générativistes en ont d’ailleurs conclu qu’elles étaient identiques dans la majeure partie de leur genèse. Pourtant, l’insertion de ces deux structures en discours est contrainte de manière très différente par le cotexte gauche, et elles ne répondent pas non plus aux mêmes fonctionnalités du point de vue de la structure informationnelle. Par exemple, le constituant disloqué ne peut être que topique à l’échelle de la proposition, alors que le constituant antéposé peut également être focus ; par ailleurs, l’insertion en discours d’une structure antéposée est plus fortement contrainte par le cotexte gauche, et pourtant, en anglais, cette structure est bien plus fréquente que la dislocation. La présente étude vise à comparer les deux structures, pour préciser leurs fonctionnalités et les contraintes d’emploi, mais aussi pour voir dans quelle mesure la position non canonique du constituant disloqué ou antéposé à l’initiale influe sur ces fonctionnalités. L’analyse invite à conclure que la position initiale a une influence, mais qu’il existe un facteur encore plus important, à savoir la manière dont le constituant placé à l’initiale est rattaché syntaxiquement à la proposition noyau.Among the non canonical utterances of English, two show in initial position a constituent whose referent is a participant in the event. These two structures are preposing and left dislocation. Some generative studies have concluded that their generation was largely similar. Yet they do not abide by the same constraints in discourse and do not share the same roles in the information structure. For example, a dislocated constituent may only be a topic at clause level, while a

  13. Tachycardies ventriculaires catécholergiques chez l'enfant

    NARCIS (Netherlands)

    Denjoy, I.; Postma, A. V.; Lupoglazoff, J. M.; Vaksman, G.; Kamblock, J.; Leenhardt, A.; Wilde, A. A.; Guicheney, P.

    2005-01-01

    Catecholinergic ventricular tachycardia is an adrenergic induced polymorphic ventricular arrhythmia. It occurs in infancy and is responsible for syncope and sudden death in the absence of any morphological cardiac abnormality. Without treatment the mortality in catecholinergic ventricular

  14. rive gauche du fleuve Rimac

    International Development Research Centre (IDRC) Digital Library (Canada)

    tégée du fleuve et les terrains vagues d'une zone industrielle. .... Ces deux diagnostics sont d'importants outils qui contri- bueront à une meilleure planification ... conditions et instruments nécessaires pour améliorer la situation financière des ...

  15. Can acyclic conformational control be achieved via a sulfur–fluorine gauche effect?† †Electronic supplementary information (ESI) available. CCDC 1048074–1048078. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c5sc00871a

    Science.gov (United States)

    Thiehoff, C.; Holland, M. C.; Daniliuc, C.

    2015-01-01

    The gauche conformation of the 1,2-difluoroethane motif is known to involve stabilising hyperconjugative interactions between donor (bonding, σC–H) and acceptor (antibonding, σ*C–F) orbitals. This model rationalises the generic conformational preference of F–Cβ–Cα–X systems (φFCCX ≈ 60°), where X is an electron deficient substituent containing a Period 2 atom. Little is known about the corresponding Period 3 systems, such as sulfur and phosphorus, where multiple oxidation states are possible. Conformational analyses of β-fluorosulfides, -sulfoxides and -sulfones are disclosed here, thus extending the scope of the fluorine gauche effect to the 3rd Period (F–C–C–S(O)n; φFCCS ≈ 60°). Synergy between experiment and computation has revealed that the gauche effect is only pronounced in structures bearing an electropositive vicinal sulfur atom (S+–O–, SO2). PMID:29511517

  16. Research

    African Journals Online (AJOL)

    ebutamanya

    2 nov. 2015 ... L'échodoppler cardiaque trans-thoracique avait retrouvé un rétrécissement mitral dans 6 cas, une prothèse mitrale ou aortique dans 05 cas, une cardiomyopathie dilaté dans 04 cas, une végétation aortique, un contraste spontané et un thrombus intra- ventriculaire gauche dans respectivement 3 et 2 cas.

  17. Polymorfe ventriculaire tachycardie met torsades de pointes bij gebruik van terodiline (Mictrol)

    NARCIS (Netherlands)

    van der Klauw, M M; van Rey, F J; Stricker, B H

    1992-01-01

    A 63-year-old female was admitted to the hospital because of collapse. She had no history of cardiovascular disease. Prior to admission she used co-trimoxazole, paracetamol, calcium tablets and 50 mg terodiline (Mictrol) daily because of bladder instability. Electrocardiography showed QT

  18. Le syntagme prépositionnel à la périphérie gauche en Taqbaylit

    OpenAIRE

    Bendjaballah, Sabrina; Ben Si Saïd, Samir; Haiden, Martin

    2017-01-01

    Dans cet article, nous examinons les constructions interrogatives portant sur un groupe prépositionnel dans un réseau de 10 points d’enquête en Kabylie. Certaines de ces constructions sont caractérisées par la préfixation de la préposition (P) sur le complémenteur (C). Nous mettons en évidence que si, dans une construction interrogative portant sur un complément prépositionnel, C est spécifié par un constituant interrogatif, alors C ne porte pas de P préfixée. Si C est spécifié par un constit...

  19. Implication of MMP and TIMP in the matrice remodeling: early and delayed radiation effects of the digestive tractus; Implication des MMP et des TIMP dans le remodelage matriciel: effets aigus et tardifs de l'irradiation du tractus digestif

    Energy Technology Data Exchange (ETDEWEB)

    Strup-Perrot, C

    2004-12-15

    irradiation induces a marked acute remodeling of the gut wall and may lead to late fibrosis. Combining morphological, biochemical and molecular approach, we studied the expression of MMP and TIMP in the ileum and colon of rats one to seven days after irradiation and in ileum of patients with radiation enteritis. In both studies expression and activity of MMP and TIMP were increased, their balance being in favor of extra-cellular matrix degradation in the acute phase while in favor of matrix accumulation in radiation enteritis. (author)

  20. Implication of MMP and TIMP in the matrice remodeling: early and delayed radiation effects of the digestive tractus; Implication des MMP et des TIMP dans le remodelage matriciel: effets aigus et tardifs de l'irradiation du tractus digestif

    Energy Technology Data Exchange (ETDEWEB)

    Strup-Perrot, C

    2004-12-15

    irradiation induces a marked acute remodeling of the gut wall and may lead to late fibrosis. Combining morphological, biochemical and molecular approach, we studied the expression of MMP and TIMP in the ileum and colon of rats one to seven days after irradiation and in ileum of patients with radiation enteritis. In both studies expression and activity of MMP and TIMP were increased, their balance being in favor of extra-cellular matrix degradation in the acute phase while in favor of matrix accumulation in radiation enteritis. (author)

  1. 18 octobre 2013 - Le Préfet de l’Ain L. Touvet signe le livre d'or avec le Directeur général du CERN R. Heuer et le Chef du Département Technologie F. Bordry. Photo de groupe, de gauche à droite: T. Kupisz, Secrétaire général de la sous préfecture de Gex; L. Miralles, Chef du Département Infrastructure et services généraux; F. Eder, Délégué aux Relations avec les Etats hôtes; S. Donnot, Sous-préfet de Gex; L. Touvet, Préfet de l'Ain; E. Sches, Sous-préfète de Nantua; E.Gröniger-Voss, Conseiller juridique du CERN; R. Heuer, Directeur général; F. Bordry, Chef du Département Technologie et P. Bloch, Chef du Département Physique.

    CERN Multimedia

    Anna Pantelia

    2013-01-01

    18 octobre 2013 - Le Préfet de l’Ain L. Touvet signe le livre d'or avec le Directeur général du CERN R. Heuer et le Chef du Département Technologie F. Bordry. Photo de groupe, de gauche à droite: T. Kupisz,\tSecrétaire général de la sous préfecture de Gex; L. Miralles, Chef du Département Infrastructure et services généraux; F. Eder, Délégué aux Relations avec les Etats hôtes; S. Donnot, Sous-préfet de Gex; L. Touvet, Préfet de l'Ain; E. Sches, Sous-préfète de Nantua; E.Gröniger-Voss, Conseiller juridique du CERN; R. Heuer, Directeur général; F. Bordry, Chef du Département Technologie et P. Bloch, Chef du Département Physique.

  2. Remodelage des temps et des espaces de travail chez les travailleurs indépendants de l’informatique : l’affrontement des effets de marchés et des préférences personnelles Software freelancers remodel their working time and space: the clash between market effects and personal preference

    Directory of Open Access Journals (Sweden)

    Diane-Gabrielle Tremblay

    2009-11-01

    Full Text Available Cette recherche s’intéresse à la perméabilité spatiale et temporelle des frontières entre le travail et le hors travail chez les travailleurs indépendants de l’informatique. Cette perméabilité participe d’une certaine recomposition des lieux et des temps de travail, permise par les TIC, mais sans doute en partie impulsée par la pression du marché, ou la concurrence entre travailleurs, dans ce secteur de travail. Les travailleurs indépendants de l’informatique constituent un groupe de travailleurs qui combine une utilisation intense des technologies et une relative autonomie dans le travail. Après un état des lieux de la perméabilité spatiale et temporelle du travail chez ces travailleurs, nous pouvons distinguer deux groupes, un premier groupe pour lequel les frontières sont très perméables (comportement intégrateur et un second pour lequel les frontières sont imperméables (comportement séparateur. Nous constatons aussi que les divers clients de ces contractuels ont une forte incidence sur l’organisation de leur temps de travail, mais aussi de leur espace de travail. Il semble donc bien y avoir un effet de marché, tout au moins en partie, même si les travailleurs autonomes de l’informatique ont tenté de se donner une certaine maîtrise temporelle.Our research inquired into the spatial and temporal permeability of borders separating work and off-work among independent software employees. Such permeability is part of the remodeling process of working time and place that ICT allows for, though doubtless under the influence of the market or of competition between workers in that sector. Freelance software workers are a group that combines an intensive use of technology with relative autonomy. After reporting on the state of the art on the subject of porous spatial and temporal borders between work and off-work among them, two groups will be distinguished: one for whom frontiers are very permeable (integrating behavior, another for whom they are impermeable (separating behavior. We also note that the different clients of these freelancers strongly impact how they organize their working time, as well as their working space. It would seem that a market effect is in fact present, at least in part, even though the autonomous software freelancer tries to gain some control over time.

  3. Configuration-dependent conformational transmission in trigonal-bipyramidal phosphorus(V) compounds. Enhanced gauche (-) population around the C(5)-C(6) linkage in 6-phosphorus(V) phosphorylated tetramethyl-a-D-galactopyranoside

    NARCIS (Netherlands)

    Vries, de N.K.; Buck, H.M.

    1986-01-01

    A 300-MHz 1H NMR variable-temperature study of the 1'-phosphorylated trigonal-bipyramidal (TBP) tetrahydropyran-2-methyl model compound 4 is reported. For this compound, in which both the equatorial and axial sites undergoing phosphorus pseudorotation bear a tetrahydro-pyran-2-methyl group, a

  4. Anatomical variants of the internal spermatic vein discovered during the percutaneous embolization of left varicoceles in a pediatric population; Variantes anatomiques de la veine spermatique lors du traitement endovasculaire des varicoc es gauches : une serie pediatrique

    Energy Technology Data Exchange (ETDEWEB)

    Garel, L.; Dubois, J.; Rypens, F.; Ouimet, A.; Yazbeck, S. [Univ. of Montreal, Sainte-Justine Hospital, Montreal, Quebec (Canada)]. E-mail: laurent_garel@ssss.gouv.qc.ca

    2004-02-01

    To report on the high incidence of anatomical variants of the origin and course of the internal spermatic vein (ISV) discovered at the time of percutaneous embolization of left varicoceles in a pediatric population. We reviewed retrospectively the 65 cases of left varicocele treated by percutaneous embolization (grade II and III) in our institution between 1990 and 2000. The course of the left renal vein (LRV), the origin of the ISV, and the number of ISVs and their pathway were recorded in all cases, according to the B ren classification. In 37/65 (57%), the ISV was single and arose from a normal LRV (type I).The following variants were encountered: type V - circumaortic LRV 9/65 (14%); type IVb - intrarenal origin of ISV 8/65 (12%); type II - multiple ISV 5/65 (8%); and pelvic collaterals 6/65 (9%). Venous anatomical variants are frequently encountered (43%) at the time of left varicocele embolization in children. Such variants often impose some adjustments to the technique of embolization and, at times, hamper the procedure. (author)

  5. Recherche d'un Higgs doublement chargé à l'aide du détecteur ATLAS dans le cadre d'un Modèle de Symétrie Gauche-Droite

    CERN Document Server

    Ferland, Jonathan

    To be able to explain the fact that, in the Standard Mo del weak interactions only a ect left handed particles, it is possible to dev elop left - righ t symmetric mo dels, where the symmetry is brok en to explain the low energy spectrum. Some of these mo dels predict the existence of a doubly charged Higgs. With the future startup of the LHC, it would be possible to disco ver suc h a particle. The mo del we will discuss in this documen t uses two Higgs triplets to break the left - righ t symmetry . Those triplets imply the existence of ++ L and ++ R . We then study single pro duction by vector boson fusion and pair pro duction by a Drell-Y an pro cess for ++ L;R and their deca y in the ATLAS detector at LHC. Disco very poten tial of those particles will be tak en into accoun t for several deca y channels. We will concen trate on leptonic channels, because they pro vide clear signatures in a detector. Other mo des exist, but they are suppressed by kinematics. We nd that for vector boson fusion, the doubly ...

  6. STUDIES OF CHANGES OF SOME BLOOD PARAMETERS AMONG ...

    African Journals Online (AJOL)

    31 déc. 2009 ... 2Departement d'hydrogéologie, Université de Tébessa, Algérie. ... directe à tout type de dégagements des cimenteries ce qui influe sur les différentes ..... ventriculaire. inflammation et coagulation l'étude d'Erfurt (Allemagne).

  7. Association entre les hormones sexuelles, les marqueurs de ...

    African Journals Online (AJOL)

    Introduction: Le présent travail se propose d'étudier la relation entre les hormones sexuelles, notamment l'oestradiol et l'indice de l'oestradiol libre, le sulfate de déhydroépiandrosterone et la sex hormone binding globulin, les marqueurs de remodelage osseux et la densité minérale osseuse chez une population de ...

  8. Contribution of the deep-inspiration breath-hold technique in patients treated for a left breast cancer by mono-isocentric conformational irradiation; Apport du blocage inspiratoire profond chez des patientes traitees pour un cancer du sein gauche par irradiation conformationnelle mono-isocentrique

    Energy Technology Data Exchange (ETDEWEB)

    Zioueche, A.; Mege, A.; Bodez, V.; Rauglaudre, G. de [Institut Sainte-Catherine, Avignon (France)

    2011-10-15

    The authors report a study which aimed at assessing the benefit of a deep-inspiration-breath-hold on heart sparing in 31 women treated in the left breast or wall and locoregional ganglionary areas by three-dimensional conformational irradiation with field-in-field optimization. All heart and lung parameters (delivered doses) have been significantly improved by a deep-inspiration-breath-hold. Short communication

  9. L\\'hydrocephalie Chronique De L\\'adulte : A Propos De 15 Cas | Ba ...

    African Journals Online (AJOL)

    Introduction L\\'hydrocéphalie chronique de l\\'adulte (HCA), est une dilatation des cavités ventriculaires par trouble de l\\'hydrodynamique du liquide cérébro-spinal (LCS), s\\'exprimant cliniquement par la triade d\\'Adams-Hakim. La cause peut être identifiable ou idiopathique. Objectifs L\\'objectif de notre travail est de ...

  10. N,N′-(Ethane-1,2-diyldibenzenecarbothioamide

    Directory of Open Access Journals (Sweden)

    Masayuki Nagasawa

    2014-05-01

    Full Text Available The title compound, C16H16N2S2, adopts a gauche+–gauche+–gauche+ (g+g+g+ conformation in the NH—CH2—CH2—NH bond sequence. In the crystal, molecules are connected by pairs of N—H...S=C hydrogen bonds and C—H...π interactions, forming a tape structure along the c-axis direction.

  11. 1,2-Difluoroethane: the angular dependance on 1J(CF) coupling constants is independent of hyperconjugation.

    Science.gov (United States)

    Freitas, Matheus P; Bühl, Michael; O'Hagan, David

    2012-02-28

    1,2-Difluoroethane is widely recognised to adopt a lower energy gauche rather than anti conformation; this gauche effect has its origin in hyperconjugation; however, surprisingly the (1)J(CF) coupling constant is not influenced by hyperconjugation; instead, its magnitude changes with the overall molecular dipole. This journal is © The Royal Society of Chemistry 2012

  12. Second Harmonic Generation, Electrooptical Pockels Effect, and Static First-Order Hyperpolarizabilities of 2,2′-Bithiophene Conformers: An HF, MP2, and DFT Theoretical Investigation

    Directory of Open Access Journals (Sweden)

    Andrea Alparone

    2013-01-01

    Full Text Available The static and dynamic electronic (hyperpolarizabilities of the equilibrium conformations of 2,2′-bithiophene (anti-gauche and syn-gauche were computed in the gas phase. The calculations were carried out using Hartree-Fock (HF, Møller-Plesset second-order perturbation theory (MP2, and density functional theory methods. The properties were evaluated for the second harmonic generation (SHG, and electrooptical Pockels effect (EOPE nonlinear optical processes at the typical λ=1064 nm of the Nd:YAG laser. The anti-gauche form characterized by the S–C2–C2′–S dihedral angle of 137° (MP2/6-311G** is the global minimum on the potential energy surface, whereas the syn-gauche rotamer (S–C2–C2′–S = 48°, MP2/6-311G** lies ca. 0.5 kcal/mol above the anti-gauche form. The structural properties of the gauche structures are rather similar to each other. The MP2 electron correlation effects are dramatic for the first-order hyperpolarizabilities of the 2,2′-bithiophenes, decreasing the HF values by ca. a factor of three. When passing from the anti-gauche to the syn-gauche conformer, the static and frequency-dependent first-order hyperpolarizabilities increase by ca. a factor of two. Differently, the electronic polarizabilities and second-order hyperpolarizabilities of these rotamers are rather close to each other. The syn-gauche structure could be discriminated from the anti-gauche one through its much more intense SHG and EOPE signals.

  13. Broadband Chirped-Pulse Fourier-Transform Microwave Spectroscopic Investigation of the Structures of Three Diethylsilane Conformers

    Science.gov (United States)

    Steber, Amanda L.; Obenchain, Daniel A.; Peebles, Rebecca A.; Peebles, Sean A.; Neill, Justin L.; Muckle, Matt T.; Pate, Brooks H.; Guirgis, Gamil A.

    2009-06-01

    The rotational spectrum of diethylsilane has been assigned using broadband chirped-pulse Fourier-transform microwave (CP-FTMW) spectroscopy. Previously, Fourier-transform microwave rotational spectra were observed using a Balle-Flygare type instrument for the ^{28}Si isotopologues of the gauche-gauche, trans-gauche, and trans-trans conformers. In the present study, a broadband microwave spectrum was obtained at the University of Virginia, taking advantage of the ability to perform deep signal averaging to increase the measurement sensitivity. To obtain a full structural determination of the conformers of this molecule, spectra for the ^{29}Si, ^{30}Si, and single ^{13}C substitutions for the gauche-gauche, the trans-gauche, and the trans-trans species were assigned. Substitution (r_s) structures and inertial fit (r_0) structures were determined and a comparison between the experimental and ab initio structures will be presented. For the ^{28}Si isotopologues, the percent differences between the experimental and ab initio rotational constants are less than 1.5% for the trans-trans and trans-gauche and are between 2.0 and 5.0% for the gauche-gauche conformer. The structural parameters will be compared between this molecule, diethylgermane and other silicon containing molecules and the relative abundances of the three conformers will be discussed. S.A. Peebles, M.M. Serafin, R.A. Peebles, G.A. Guirgis, and H.D. Stidham J. Phys. Chem. A, (2009), DOI: 10.1021/jp811049n.

  14. Removal of phase transfer agent leads to restricted dynamics of ...

    Indian Academy of Sciences (India)

    Wintec

    has been investigated by infrared (IR) and nuclear magnetic resonance (NMR) spectroscopies. The experi- ... gauche defects near the head group for the 3D SAMs similar to 2D ... chain motion is more restricted in hydroxyl termi- nated SAMs.

  15. (E-N′-(4-Pyridylmethylene-4-(8-quinolyloxybutanohydrazide 0.25-hydrate

    Directory of Open Access Journals (Sweden)

    Jia-Ming Li

    2009-02-01

    Full Text Available The asymmetric unit of the title compound, C19H18N4O2·0.25H2O, contains two organic molecules and a solvent water molecule with 50% occupancy. The two molecules differ in their conformations: in one molecule it is (+gauche-trans-trans-(+gauche-trans, whereas in the other it is (−gauche-trans-trans-(−gauche-trans. The dihedral angles between the pyridine ring and the quinoline ring system are 67.4 (3 and 68.0 (2°. Molecules are linked into a supramolecular two-dimensional array via N—H...N hydrogen bonds, with each partially occupied water molecule connected via an O—H...O hydrogen bond. C—H...O interactions are also present.

  16. Collaboration between the CERN Apprenticeship Service and the Geneva industrial organization, Union Industrielle Genevoise (UIG)

    CERN Multimedia

    Damien Gillieron

    1999-01-01

    De gauche a droite: C. Monney, laureat; W. Blair, chef des Services Educatifs; Y. Zaugg, President de l'UIG; A. Romanens, laureat; R. Gay, responsable des apprentissages techniques et P. Lathuiliere, delegue pour la formation de l'UIG

  17. Nedelja modõ v Parizhe

    Index Scriptorium Estoniae

    2004-01-01

    Naistemoe nädal Pariisis näitab valmisriideid kevad-suveks 2005. Kollektsioonid John Gallianolt (Dior), Jean Paul Gaultier'lt (Hermes), Stefano Pilatilt (YSL Rive Gauche), Roberto Menichettilt (Celine)

  18. Images in medicine

    African Journals Online (AJOL)

    ebutamanya

    30 juil. 2015 ... d'hémorragies et de nodules cotonneux à droite et un foyer de rétinite nasal actif, extensif à gauche. L'Angiographie à la fluorescéine objectivait une hypofluorescence rétinienne en faveur d'un foyer de rétinite profond gauche. Dans ce contexte d'immunodépression et devant l'aspect clinique évocateur, le.

  19. Sarcome d'Ewing de localisation pétreuse | Lahiani | Pan African ...

    African Journals Online (AJOL)

    La TDM des rochersa révélé un processus tissulaire du conduit auditif externe gauche, étendu à l'oreille moyenne avec lyse du mur de la logette et de l'os temporal. L'IRM des rochers a montré le même processus avec envahissement de la parotide gauche, en hyposignal T1, se réhaussant après injection de gadolinium.

  20. African Journal of Neurological Sciences - 2009 Vol. 28 No 1

    African Journals Online (AJOL)

    Observation. Un homme âgé de 43 ans, présentait une inflammation conjonctivale de l'oeil gauche évoluant depuis 14 ans, avec apparition progressive d'un ectropion avec exophtalmie axile irréductible et indolore aggravée d'une ophtalmoplégie et cécité gauches. L'IRM orbitaire a mis en évidence une masse ...

  1. Structural characterization of dioscorin, the major tuber protein of yams, by near infrared Raman spectroscopy

    International Nuclear Information System (INIS)

    Liao, Y-H; Tseng, C-Y; Chen Wenlung

    2006-01-01

    As very little is known about the molecular structure of dioscorin, the major storage protein of yam tuber, we report here FT-Raman spectroscopic investigation of this yam protein isolated from D. alata L., for the first time. According to a series of purification and identification by ion-exchange chromatography, gel chromatography, SDS-PAGE, and MALDI-TOF-MS, it shows that the major storage protein is made up of dioscorin A (M.W. ∼33 kDa) and dioscorin B (M.W. ∼31 kDa). Raman spectral results indicate that the secondary structure of dioscorin A is major in α-helix, while dioscorin B belongs to anti-parallel β- sheet. It also shows that the microenvironment of major amino acids including tyrosine, phenylalanine, tryptophan, and methionine, and cysteine exhibit explicit differences between these two components. The conformation of disulfide bonding in dioscorin A predominates in Gauche-Gauche-Trans form, while Gauche-Gauche-Gauche and Trans-Gauche-Trans share the conformation in dioscorin B. Structural resemblance between dioscorin A and crude yam proteins implies that dioscorin A exhibits structural preference even though its content is lower than dioscorin B

  2. Structural characterization of dioscorin, the major tuber protein of yams, by near infrared Raman spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Liao, Y-H [300 University Road, Department of Food Science, National Chiayi University, Chiayi, Taiwan (China); Tseng, C-Y [300 University Road, Department of Food Science, National Chiayi University, Chiayi, Taiwan (China); Chen Wenlung [Department of Chemistry, National Chiayi University, Chiayi, Taiwan (China)

    2006-01-01

    As very little is known about the molecular structure of dioscorin, the major storage protein of yam tuber, we report here FT-Raman spectroscopic investigation of this yam protein isolated from D. alata L., for the first time. According to a series of purification and identification by ion-exchange chromatography, gel chromatography, SDS-PAGE, and MALDI-TOF-MS, it shows that the major storage protein is made up of dioscorin A (M.W. {approx}33 kDa) and dioscorin B (M.W. {approx}31 kDa). Raman spectral results indicate that the secondary structure of dioscorin A is major in {alpha}-helix, while dioscorin B belongs to anti-parallel {beta}- sheet. It also shows that the microenvironment of major amino acids including tyrosine, phenylalanine, tryptophan, and methionine, and cysteine exhibit explicit differences between these two components. The conformation of disulfide bonding in dioscorin A predominates in Gauche-Gauche-Trans form, while Gauche-Gauche-Gauche and Trans-Gauche-Trans share the conformation in dioscorin B. Structural resemblance between dioscorin A and crude yam proteins implies that dioscorin A exhibits structural preference even though its content is lower than dioscorin B.

  3. Structural characterization of dioscorin, the major tuber protein of yams, by near infrared Raman spectroscopy

    Science.gov (United States)

    Liao, Yu-Hsiu; Tseng, Chi-Yin; Chen, Wenlung

    2006-01-01

    As very little is known about the molecular structure of dioscorin, the major storage protein of yam tuber, we report here FT-Raman spectroscopic investigation of this yam protein isolated from D. alata L., for the first time. According to a series of purification and identification by ion-exchange chromatography, gel chromatography, SDS-PAGE, and MALDI-TOF-MS, it shows that the major storage protein is made up of dioscorin A (M.W. ~33 kDa) and dioscorin B (M.W. ~31 kDa). Raman spectral results indicate that the secondary structure of dioscorin A is major in α-helix, while dioscorin B belongs to anti-parallel β- sheet. It also shows that the microenvironment of major amino acids including tyrosine, phenylalanine, tryptophan, and methionine, and cysteine exhibit explicit differences between these two components. The conformation of disulfide bonding in dioscorin A predominates in Gauche-Gauche-Trans form, while Gauche-Gauche-Gauche and Trans-Gauche-Trans share the conformation in dioscorin B. Structural resemblance between dioscorin A and crude yam proteins implies that dioscorin A exhibits structural preference even though its content is lower than dioscorin B.

  4. Analysis of internal structure changes in black human hair keratin fibers resulting from bleaching treatments using Raman spectroscopy

    Science.gov (United States)

    Kuzuhara, Akio

    2013-09-01

    In order to investigate in detail the internal structure changes in virgin black human hair keratin fibers resulting from bleaching treatments, the structure of cross-sections at various depths of black human hair, which had been impossible due to high melanin grande content, was directly analyzed using Raman spectroscopy. The gauche-gauche-gauche (GGG) content of the sbnd SSsbnd groups existing from the cuticle region to the center of cortex region of the virgin black human hair remarkably decreased, while the gauche-gauche-trans and trans-gauche-trans contents were not changed by performing the excessive bleaching treatment. In particular, it was found that not only the β-sheet and/or random coil content, but also the α-helix content existing throughout the cortex region of virgin black human hair decreased. In addition, the transmission electron microscope observation shows that the proteins in the cell membrane complex, the cuticle and cortex of the virgin black human hair were remarkably eluted by performing the excessive bleaching treatment. From these experiments, the author concluded that the sbnd SSsbnd groups, which have a GGG conformation were decomposed and finally converted to cysteic acid, and the α-helix structure of some of the proteins existing in the keratin was changed to the random coil structure, or eluted from the cortex region, thereby leading to the reduction in the protein density of the virgin human hair after the excessive bleaching treatment.

  5. Structures and Nuclear Quadrupole Coupling Tensors of a Series of Chlorine-Containing Hydrocarbons

    Science.gov (United States)

    Dikkumbura, Asela S.; Webster, Erica R.; Dorris, Rachel E.; Peebles, Rebecca A.; Peebles, Sean A.; Seifert, Nathan A.; Pate, Brooks

    2016-06-01

    Rotational spectra for gauche-1,2-dichloroethane (12DCE), gauche-1-chloro-2-fluoroethane (1C2FE) and both anti- and gauche-2,3-dichloropropene (23DCP) have been observed using chirped-pulse Fourier-transform microwave (FTMW) spectroscopy in the 6-18 GHz region. Although the anti conformers for all three species are predicted to be more stable than the gauche forms, they are nonpolar (12DCE) or nearly nonpolar (predicted dipole components for anti-1C2FE: μ_a = 0.11 D, μ_b = 0.02 D and for anti-23DCP: μ_a = 0.25 D, μ_b = 0.02 D); nevertheless, it was also possible to observe and assign the spectrum of anti-23DCP. Assignments of parent spectra and 37Cl and 13C substituted isotopologues utilized predictions at the MP2/6-311++G(2d,2p) level and Pickett's SPCAT/SPFIT programs. For the weak anti-23DCP spectra, additional measurements also utilized a resonant-cavity FTMW spectrometer. Full chlorine nuclear quadrupole coupling tensors for gauche-12DCE and both anti- and gauche-23DCP have been diagonalized to allow comparison of coupling constants. Kraitchman's equations were used to determine r_s coordinates of isotopically substituted atoms and r_0 structures were also deduced for gauche conformers of 12DCE and 1C2FE. Structural details and chlorine nuclear quadrupole coupling constants of all three molecules will be compared, and effects of differing halogen substitution and carbon chain length on molecular properties will be evaluated.

  6. Troubles du rythme liés à l’administration des inhibiteurs de la tyrosine kinase dans la leucémie myéloïde chronique

    OpenAIRE

    Spechbach, Hervé

    2016-01-01

    Le cas présenté dans l’article référencé permet de soupçonner un lien de l’ordre du probable selon l’organisation mondiale de la santé (OMS), entre le dasatinib (Sprycel®) et une arythmie ventriculaire. En complément, cette thèse fait le point sur les connaissances médicales actuelles quant aux arythmies cardiaques potentiellement liées aux inhibiteurs de tyrosine kinases. Selon la base de données mondiale de l’OMS sur les effets secondaires des médicaments, des centaines de cas ont été décla...

  7. Interplay between intramolecular and intermolecular structures of 1,1,2,2-tetrachloro-1,2-difluoroethane

    Science.gov (United States)

    Rovira-Esteva, M.; Murugan, N. A.; Pardo, L. C.; Busch, S.; Tamarit, J. Ll.; Pothoczki, Sz.; Cuello, G. J.; Bermejo, F. J.

    2011-08-01

    We report on the interplay between the short-range order of molecules in the liquid phase of 1,1,2,2-tetrachloro-1,2-difluoroethane and the possible molecular conformations, trans and gauche. Two complementary approaches have been used to get a comprehensive picture: analysis of neutron-diffraction data by a Bayesian fit algorithm and a molecular dynamics simulation. The results of both show that the population of trans and gauche conformers in the liquid state can only correspond to the gauche conformer being more stable than the trans conformer. Distinct conformer geometries induce distinct molecular short-range orders around them, suggesting that a deep intra- and intermolecular interaction coupling is energetically favoring one of the conformers by reducing the total molecular free energy.

  8. Molecular structure and conformation of two acyclic polythioethers: Implications for the design of heavy metal chelators

    Energy Technology Data Exchange (ETDEWEB)

    Desper, J.M.; Powell, D.R.; Gellman, S.H. (Univ. of Wisconsin, Madison (USA))

    1990-05-23

    The crystal structures of the 1,9-bis(p-tolyl)-2,5,8-trithianonane (1) and 1,12-bis(p-tolyl)-2,5,8,11-tetrathiadodecane (2) are reported. Previous studies of macrocyclic polythioethers have revealed a pronounced tendency for backbone CS-CC bonds to adopt gauche torsion angles. The same tendency is observed in the homologous acyclic polythioethers 1 and 2, demonstrating that the gauche preference is not simply the result of a macrocyclic constraint. Because of this gauche preference of CS-CC torsion units and the well-established anti preference of SC-CS torsion units, polythioethers constructed from ethylene sulfide subunits are generally far from preorganized for metal ion chelation.

  9. Density functional study of gamma-aminopropyltriethoxysilane

    International Nuclear Information System (INIS)

    Bistricic, L; Volovsek, V; Daani, V; Leskovac, M

    2006-01-01

    Density functional theory calculations using Becke's three-parameter exchange functional in combination with the Lee-Young-Parr correlation functional (B3-LYP) and standard 6-311 + G(d,p) basis set were carried out to study the conformational stability and vibrational spectra of gamma-aminopropyltriethoxysilane. Calculations reveal the existence of two stable conformers trans and gauche. The calculated energy for the gauche conformation was found to be 608 cm -1 above the minimum energy of the trans conformation. Temperature dependence of Raman spectra of liquid APTES and DFT calculation enabled us to identify the vibrational bands characteristic for both conformers. It has been shown that there is an increase in the population of gauche conformer with increasing temperature

  10. Interplay between intramolecular and intermolecular structures of 1,1,2,2-tetrachloro-1,2-difluoroethane

    OpenAIRE

    Rovira Esteva, M.; Murugan, N.A.; Pardo, L.C.; Busch, S.; Tamarit, J.Ll.; Pothoczki, Sz.; Cuello, G. J.; Bermejo, Francisco Javier

    2011-01-01

    We report on the interplay between the short-range order of molecules in the liquid phase of 1,1,2,2-tetrachloro-1,2-difluoroethane and the possible molecular conformations, trans and gauche. Two complementary approaches have been used to get a comprehensive picture: analysis of neutron-diffraction data by a Bayesian fit algorithm and a molecular dynamics simulation. The results of both show that the population of trans and gauche conformers in the liquid state can only correspond to the gauc...

  11. Rebels with a Cause, The Failure of the Left in Iran. London, I. B. Tauris, 1999, 239 p.

    OpenAIRE

    Balaÿ, Christophe

    2010-01-01

    L’A., professeur assistant à l’Université de San Francisco, brosse la fresque de l’histoire de la gauche iranienne depuis 1953 jusqu’à 1983. Ces trente années décisives pour le destin de l’Iran, sont aussi cruciales et amères pour les partis de la gauche iranienne qui par ses erreurs d’analyse et de choix stratégiques comme de comportement, échoue dans la prise du pouvoir et surtout dans la conscience populaire iranienne. L’A. construit sa réflexion en trois temps historiques : l’effondrement...

  12. The interplay between transient a-helix formation and side chain rotamer distributions in disordered proteins probed by methyl chemical shifts

    DEFF Research Database (Denmark)

    Kjærgaard, Magnus; Iesmantavicius, Vytautas; Poulsen, Flemming M

    2011-01-01

    and retinoid receptors (ACTR). We find that small differences in the methyl carbon chemical shifts due to the ¿-gauche effect may provide information about the side chain rotamer distributions. However, the effects of neighboring residues on the methyl group chemical shifts obscure the direct observation...... of ¿-gauche effect. To overcome this, we reference the chemical shifts to those in a more disordered state resulting in residue specific random coil chemical shifts. The (13)C secondary chemical shifts of the methyl groups of valine, leucine, and isoleucine show sequence specific effects, which allow...

  13. Pressure-induced phase transition of 1-butyl-3-methylimidazolium hexafluorophosphate [bmim][PF6

    Science.gov (United States)

    Takekiyo, Takahiro; Hatano, Naohiro; Imai, Yusuke; Abe, Hiroshi; Yoshimura, Yukihiro

    2011-03-01

    We have investigated the pressure-induced Raman spectral change of 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]) using Raman spectroscopy. The relative Raman intensity at 590 cm-1 of the CH2 rocking band assigned to the gauche conformer of the NCCC dihedral angle of the butyl group in the [bmim]+ cation increases when the pressure-induced liquid-crystalline phase transition occurs, while that at 610 cm-1 assigned to the trans conformer decreases. Our results show that the high-pressure phase transition of [bmim][PF6] causes the increase of the gauche conformer of the [bmim]+ cation.

  14. Pataphysique de la menace.

    Directory of Open Access Journals (Sweden)

    Nicolas Tavaglione

    2008-04-01

    Full Text Available Alors qu’on la croyait morte il y a à peine vingt ans, la gauche radicale forme pourtant aujourd’hui une galaxie vive et bouillonnante. « De l’extrême-gauche classique à l’altermondialisation », comme l’écrit Philippe Raynaud, la scène politique française fourmille aujourd’hui d’acteurs nourrissant « l’ambition de définir une “autre politique” en rupture avec le consensus libéral ou avec les formes actuelles de la mondialisation » (Raynaud, 2006 ...

  15. A confusão esquerda/direita no mundo pós-Muro de Berlim: uma análise e uma hipótese

    Directory of Open Access Journals (Sweden)

    Angelo Segrillo

    2004-01-01

    Full Text Available Dans cet article, on analyse les transformations qu'ont subies les concepts de gauche et droite dans le monde après la chute du Mur de Berlin et la désagrégration de l'URSS. On y examine les conséquences au Brésil de ces changements historiques et théoriques en posant l'hypothèse selon laquelle la gauche est historiquement le primum mobile des changements radicaux dans la dynamique des systèmes de partis dans leur ensemble.

  16. Commerces turco-kurdes dans le quartier Wood Green de Londres

    OpenAIRE

    Rigoni , Isabelle

    2002-01-01

    De gauche à droite : un club de billard kurde de Turquie (aux couleurs kurdes : rouge, vert, jaune), un restaurant turco-kurde, une pâtisserie / salon de thé kurde (intitulée " patisserie des gens d'Antep ", en référence à la ville de Gaziantep située au Kurdistan turc).

  17. Boutiques d'alimentation turques et chypriotes dans le quartier Hackney de Londres

    OpenAIRE

    Rigoni , Isabelle

    2002-01-01

    Sur la gauche, une épicerie turque vendant des produits du Moyen-Orient ; sur la droite, une patisserie chypriote (le mot patisserie est écrit à la fois en turc et en grec). Un véhicule utilitaire garé mentionne un restaurant de tapas espagnol.

  18. A comparison and chemometric analysis of several molecular mechanics force fields and parameter sets applied to carbohydrates

    NARCIS (Netherlands)

    Perez, S; Imberty, A; Engelsen, SB; Gruza, J; Mazeau, K; Jimenez-Barbero, J; Poveda, A; Espinosa, JF; van Eyck, BP; Johnson, G; French, AD; Louise, M; Kouwijzer, CE; Grootenuis, PDJ; Bernardi, A; Raimondi, L; Senderowitz, H; Durier, [No Value; Vergoten, G; Rasmussen, K

    1998-01-01

    Carbohydrates are thought to be especially difficult to model because of their highly polar functionality, their flexibility, and their differences in electronic arrangements that occur during conformational and configurational changes, such as the anomeric, exo-anomeric and gauche effects. These

  19. South African Journal of Higher Education - Vol 21, No 1 (2007)

    African Journals Online (AJOL)

    Burnout and engagement in university students: A psychometric analysis of the MBI-SS and UWES-S · EMAIL FULL TEXT EMAIL FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. K Mostert, J Pienaar, C Gauche, LTB Jackson, 147-162 ...

  20. Mise au point

    African Journals Online (AJOL)

    31 mai 2013 ... latérale. elle était de siège droit dans 6 cas et gauche ... exam. CT scan was systematically done. mrI was realized in case of a diagnostic doubt. eight of our patients were trea- .... de corps étranger dans la gorge [5] [7] [8].

  1. Les traumatismes du diaphragme en urgence clinique et ...

    African Journals Online (AJOL)

    The male predominance was clean with a sex ratio of 5. The middle age ... The exam clinic and the x-ray standard of the thorax permit the diagnosis. ... La coupole droite était lésée dans 45,2% des cas et dans 54,8% la lésion était à gauche.

  2. Comparison of the one-electron oxidations of CO-bridged vs unbridged bimetallic complexes: Electron-transfer chemistry of Os2Cp2(CO)4 and Os2Cp∗2(μ-CO)2(CO)2 (Cp = η5-C5H5, Cp∗ = η5-C5Me5)

    KAUST Repository

    Laws, Derek R.; Bullock, Morris Morris; Lee, Richmond; Huang, Kuo-Wei; Geiger, William E.

    2014-01-01

    with an approximately 1:1 mixture of anti and gauche structures for the 33 e- radical cation in which it has retained all-terminal bonding of the CO ligands. Density functional theory (DFT) calculations, including orbital-occupancy-perturbed Mayer bond-order analyses

  3. Molecular-dynamics simulation of lateral friction in contact-mode atomic force microscopy of alkane films: The role of molecular flexibility

    DEFF Research Database (Denmark)

    Soza, P.; Hansen, Flemming Yssing; Taub, H.

    2011-01-01

    than on a surface of molecules with the long axis perpendicular to the surface, in agreement with experimental results. A major dissipation mechanism is the molecular flexibility as manifested in the torsional motion about the molecules' C-C bonds. The generation of gauche defects as a result...

  4. Images in medicine

    African Journals Online (AJOL)

    abp

    un traitement endovasculaire des deux anévrismes à droite avec un rendez-vous de 3 mois pour sécuriser l'anévrisme gauche. La prévalence des anévrismes intracrâniens dans la population générale est évaluée de 1 à 5%.

  5. PYOCELE DU CORNET MOYEN : A PROPOS D'UN CAS ...

    African Journals Online (AJOL)

    L'examen clinique montrait un cornet moyen élargi obstruant la totalité de la fosse nasale gauche. ... Introduction : A mucocele is an epithelium-lined cavity that contains mucus that fills the sinus and is capable of .... rétention intramucocélique.

  6. Case report

    African Journals Online (AJOL)

    abp

    18 nov. 2012 ... A l'examen gynécologique, on note l'absence de visualisation de pertuis cervical avec au toucher vaginal et rectal un empâtement sensible vaginale gauche. .... Parant O, Monzozies X, Lemasson F. Hématocolpos su hémivagin borgne avec duplication génitale complète: diagnostic et traitement - A.

  7. The use of degradation gradients for the assessment and ecological ...

    African Journals Online (AJOL)

    The use of degradation gradients for the assessment and ecological interpretation of range condition. Guach H.G., Bosch O.J.H., Gauch H.G.. Abstract. Multivariate procedures were used to subdivide the Southern African climatic climax grasslands of the 700-800 mm rainfall zone into relatively homogeneous grazing areas.

  8. Seminar in honour of Professor Ugo Amaldi on the occasion of his 65th birthday

    CERN Multimedia

    Paulo Pascoal

    1999-01-01

    Entourant Ugo Amaldi (en haut, au centre), dans le sens des aiguilles d'une montre en partant de sa gauche : Luciano Maiani, Directeur general du CERN, G. Wolf (DESY), G. Kalmus (CERN), D. Treille (CERN), W. Schnell (retraite du CERN), P. Langacker (Universite de Pennsylvanie) et M. Goitein (Northeast Proton Therapy Center, Boston)

  9. genotype by environment interaction and grain yield stability

    African Journals Online (AJOL)

    Preferred Customer

    Farshadfar, 2008, on bread wheat; Abeya. Temesgen et al., 2008, on common bean; Girma. Mengistu et al., 2011, on Field pea). The most accurate model for AMMI can be predicted by using the first two PCAs (Gauch and. Zobel, 1996). This suggestion was later modified such that factors like type of crop, diversity of the.

  10. African Journal of Neurological Sciences - 2009 Vol. 28 No 1

    African Journals Online (AJOL)

    de la partie droite du mur postérieur. Elle occupait la partie droite du canal rachidien s'invaginant dans le trou de conjugaison correspondant avec une petite extension extracanalaire, une extension endocanalaire refoulant discrètement les racines de la queue de cheval vers la gauche et une forte prise de contraste.

  11. African Journal of Neurological Sciences 2013 - Vol. 32, No 1 http ...

    African Journals Online (AJOL)

    La chimiothérapie anticancéreuse est pourvoyeuse d'un large spectre de complications ... La survenue de cette complication dépend du type de drogue utilisé, et de ..... coagulation intravasculaire disséminée, G :gauche, D :droit, DM : donnée.

  12. Case report

    African Journals Online (AJOL)

    abp

    21 oct. 2015 ... Abstract. Le Cylindrome orbitaire (carcinome adénoide kystique) est une tumeur maligne d'agressivité locale et d'évolution lente. Sa localisation orbitaire aux dépens des glandes lacrymales est exceptionnelle. Nous rapportons le cas d'un patient de 51 ans consultant pour une exophtalmie gauche non.

  13. Case report

    African Journals Online (AJOL)

    abp

    30 sept. 2012 ... Myxome géant de l'oreillette gauche appendu à la valve mitrale hyper ... systolique, aigu, d'intensité 3/6, à type de jet de vapeur et irradiant à ... initié une anti-coagulation préventive et recommandé une éviction de tout effort.

  14. Microwave, infrared and Raman spectra, adjusted r{sub 0} structural parameters, conformational stability, and vibrational assignment of cyclopropylfluorosilane

    Energy Technology Data Exchange (ETDEWEB)

    Panikar, Savitha S. [Department of Chemistry, University of Missouri-Kansas City, Kansas City, MO 64110 (United States); Guirgis, Gamil A.; Eddens, Matthew T.; Dukes, Horace W. [Department of Chemistry and Biochemistry, College of Charleston, Charleston, SC 29424 (United States); Conrad, Andrew R.; Tubergen, Michael J. [Department of Chemistry, Kent State University, Kent, OH 44242 (United States); Gounev, Todor K. [Department of Chemistry, University of Missouri-Kansas City, Kansas City, MO 64110 (United States); Durig, James R., E-mail: durigj@umkc.edu [Department of Chemistry, University of Missouri-Kansas City, Kansas City, MO 64110 (United States)

    2013-03-29

    Highlights: ► The most stable gauche conformer has been identified from microwave spectra. ► Enthalpy difference has been determined between the two forms. ► Adjusted r{sub 0} structures were obtained for the gauche form. ► Ab initio calculations were performed for the two conformers. - Abstract: FT-microwave, infrared spectra of gas and Raman spectra of liquid for cyclopropylfluorosilane, c-C{sub 3}H{sub 5}SiH{sub 2}F have been recorded. 51 transitions for the {sup 28}Si, {sup 29}Si, and {sup 30}Si isotopomers have been assigned for the gauche conformer. Enthalpy differences in xenon solution by variable temperature infrared spectra between the more stable gauche and lesser stable cis form gave 109 ± 9 cm{sup −1}. From the microwave rotational constants for the three isotopomers ({sup 28}Si, {sup 29}Si, {sup 30}Si) combined with structural parameters predicted from MP2(full)/6-311+G(d, p) calculations, adjusted r{sub 0} structural parameters were obtained for the gauche conformer. The heavy atom distances (Å): Si–C{sub 2} = 1.836(3); C{sub 2}–C{sub 4} = 1.525(3); C{sub 2}–C{sub 5} = 1.519(3); C{sub 4}–C{sub 5} = 1.494(3); Si–F = 1.594(3) and angles (°): ∠CSiF = 111.2(5); ∠SiC{sub 2}C{sub 4} = 117.5(5); ∠SiC{sub 2}C{sub 5} = 119.2(5). To support the vibrational assignments, MP2(full)/6-31G(d) calculations were carried out. Results are discussed and compared to the corresponding properties of some similar molecules.

  15. Spectra and structure of silicon containing compounds. XXXII. Raman and infrared spectra, conformational stability, vibrational assignment and ab initio calculations of n-propylsilane-d0 and Si-d3.

    Science.gov (United States)

    Durig, James R; Pan, Chunhua; Guirgis, Gamil A

    2003-03-15

    The infrared (3100-40 cm(-1)) and Raman (3100-20 cm(-1)) spectra of gaseous and solid n-propylsilane, CH(3)CH(2)CH(2)SiH(3) and the Si-d(3) isotopomer, CH(3)CH(2)CH(2)SiD(3), have been recorded. Additionally, the Raman spectra of the liquids have been recorded and qualitative depolarization values obtained. Both the anti and gauche conformers have been identified in the fluid phases but only the anti conformer remains in the solid. Variable temperature (-105 to -150 degrees C) studies of the infrared spectra of n-propylsilane dissolved in liquid krypton have been recorded and the enthalpy difference has been determined to be 220+/-22 cm(-1) (2.63+/-0.26 kJ mol(-1)) with the anti conformer the more stable form. A similar value of 234+/-23 cm(-1) (2.80+/-0.28 kJ mol(-1)) was obtained for deltaH for the Si-d(3) isotopomer. At ambient temperature it is estimated that there is 30+/-2% of the gauche conformer present. The potential function governing the conformation interchange has been estimated from the far infrared spectral data, the enthalpy difference, and the dihedral angle of the gauche conformer, which is compared to the one predicted from ab initio MP2/6-31G(d) calculations. The barriers to conformational interchange are: 942, 970 and 716 cm(-1) for the anti to gauche, gauche to gauche, and gauche to anti conformers, respectively. Relatively complete vibrational assignments are proposed for both the n-propylsilane-d(0) and Si-d(3) molecules based on the relative infrared and Raman spectral intensities, infrared band contours, depolarization ratios, and normal coordinate calculations. The geometrical parameters, harmonic force constants, vibrational frequencies, infrared intensities, Raman activities and depolarization ratios, and energy differences have been obtained for the anti and gauche conformers from ab initio MP2/6-31G(d) calculations. Structural parameters and energy differences have also been obtained utilizing the larger 6-311 + G(d,p) and 6-311 + G(2

  16. Spectra and structure of silicon containing compounds. XXXII. Raman and infrared spectra, conformational stability, vibrational assignment and ab initio calculations of n-propylsilane-d 0 and Si-d 3

    Science.gov (United States)

    Durig, James R.; Pan, Chunhua; Guirgis, Gamil A.

    2003-03-01

    The infrared (3100-40 cm -1) and Raman (3100-20 cm -1) spectra of gaseous and solid n-propylsilane, CH 3CH 2CH 2SiH 3 and the Si-d 3 isotopomer, CH 3CH 2CH 2SiD 3, have been recorded. Additionally, the Raman spectra of the liquids have been recorded and qualitative depolarization values obtained. Both the anti and gauche conformers have been identified in the fluid phases but only the anti conformer remains in the solid. Variable temperature (-105 to -150 °C) studies of the infrared spectra of n-propylsilane dissolved in liquid krypton have been recorded and the enthalpy difference has been determined to be 220±22 cm -1 (2.63±0.26 kJ mol -1) with the anti conformer the more stable form. A similar value of 234±23 cm -1 (2.80±0.28 kJ mol -1) was obtained for Δ H for the Si-d 3 isotopomer. At ambient temperature it is estimated that there is 30±2% of the gauche conformer present. The potential function governing the conformation interchange has been estimated from the far infrared spectral data, the enthalpy difference, and the dihedral angle of the gauche conformer, which is compared to the one predicted from ab initio MP2/6-31G(d) calculations. The barriers to conformational interchange are: 942, 970 and 716 cm -1 for the anti to gauche, gauche to gauche, and gauche to anti conformers, respectively. Relatively complete vibrational assignments are proposed for both the n-propylsilane-d 0 and Si-d 3 molecules based on the relative infrared and Raman spectral intensities, infrared band contours, depolarization ratios, and normal coordinate calculations. The geometrical parameters, harmonic force constants, vibrational frequencies, infrared intensities, Raman activities and depolarization ratios, and energy differences have been obtained for the anti and gauche conformers from ab initio MP2/6-31G(d) calculations. Structural parameters and energy differences have also been obtained utilizing the larger 6-311+G(d,p) and 6-311+G(2d,2p) basis sets. From the isolated

  17. Structural changes evaluation with Raman spectroscopy in meat batters prepared by different processes.

    Science.gov (United States)

    Kang, Zhuang-Li; Li, Xiang; He, Hong-Ju; Ma, Han-Jun; Song, Zhao-Jun

    2017-08-01

    A comprehensive study was conducted to evaluate the structural changes of meat and protein of pork batters produced by chopping or beating process through the phase-contrast micrograph, laser light scattering analyzer, scanning electronic microscopy and Raman spectrometer. The results showed that the shattered myofibrilla fragments were shorter and particle-sizes were smaller in the raw batter produced by beating process than those in the chopping process. Compared with the raw and cooked batters produced by chopping process, modifications in amide I and amide III bands revealed a significant decrease of α -helix content and an increase of β -sheet, β -turn and random coils content in the beating process. The changes in secondary structure of protein in the batter produced by beating process was thermally stable. Moreover, more tyrosine residues were buried, and more gauche-gauche-trans disulfide bonds conformations and hydrophobic interactions were formed in the batter produced by beating process.

  18. Elections législatives 2007

    Directory of Open Access Journals (Sweden)

    Céline Colange

    2007-08-01

    Full Text Available Cette publication s’appuie sur l’étude cartographique des résultats du premier tour des élections législatives du mois de juin 2007 à l’échelle des 577 circonscriptions de la métropole. Outre la description et la compréhension de la dimension spatiale des votes, cet article propose quelques pistes de réflexion sur les interprétations de la carte électorale et sur son instrumentalisation possible par les médias nationaux ou locaux. En particulier, les propositions pour une refondation de la gauche seront différentes selon que l’on mette en évidence l’évolution de la gauche dans les hyper centres urbains, dans les campagnes ouvrières de l’ouest, dans les banlieues urbaines ou dans les bassins industriels.

  19. The calculations of small molecular conformation energy differences by density functional method

    Science.gov (United States)

    Topol, I. A.; Burt, S. K.

    1993-03-01

    The differences in the conformational energies for the gauche (G) and trans(T) conformers of 1,2-difluoroethane and for myo-and scyllo-conformer of inositol have been calculated by local density functional method (LDF approximation) with geometry optimization using different sets of calculation parameters. It is shown that in the contrast to Hartree—Fock methods, density functional calculations reproduce the correct sign and value of the gauche effect for 1,2-difluoroethane and energy difference for both conformers of inositol. The results of normal vibrational analysis for1,2-difluoroethane showed that harmonic frequencies calculated in LDF approximation agree with experimental data with the accuracy typical for scaled large basis set Hartree—Fock calculations.

  20. Side Chain Cyclized Aromatic Amino Acids

    DEFF Research Database (Denmark)

    Van der Poorten, Olivier; Knuhtsen, Astrid; Sejer Pedersen, Daniel

    2016-01-01

    Constraining the conformation of flexible peptides is a proven strategy to increase potency, selectivity, and metabolic stability. The focus has mostly been on constraining the backbone dihedral angles; however, the correct orientation of the amino acid side chains (χ-space) that constitute...... the peptide pharmacophore is equally important. Control of χ-space utilizes conformationally constrained amino acids that favor, disfavor, or exclude the gauche (-), the gauche (+), or the trans conformation. In this review we focus on cyclic aromatic amino acids in which the side chain is connected...... to the peptide backbone to provide control of χ(1)- and χ(2)-space. The manifold applications for cyclized analogues of the aromatic amino acids Phe, Tyr, Trp, and His within peptide medicinal chemistry are showcased herein with examples of enzyme inhibitors and ligands for G protein-coupled receptors....

  1. Fluorine substitution and nonconventional OH...pi intramolecular bond: high-resolution UV spectroscopy and ab initio calculations of 2-(p-fluorophenyl)ethanol.

    Science.gov (United States)

    Karaminkov, Rosen; Chervenkov, Sotir; Neusser, Hans J

    2008-05-21

    The para-fluorinated flexible neurotransmitter analogue 2-phenylethanol has been investigated by highly resolved resonance-enhanced two-photon ionisation two-colour UV laser spectroscopy with mass resolution and ab initio structural optimisations and energy calculations. Two stable conformations, gauche and anti, separated by a high potential barrier have been identified in the cold molecular beam by rotational analysis of the vibronic band structures. The theoretically predicted higher-lying conformations most likely relax to these two structures during the adiabatic expansion. The lowest-energy gauche conformer is stabilised by an intramolecular nonconventional OH...pi-type hydrogen bond between the terminal OH group of the side chain and the pi electrons of the phenyl ring. The good agreement between the experimental and theoretical results demonstrates that even the substitution with a strongly electronegative atom of 2-phenylethanol at the para position has no noticeable effect on the strength and orientation of the OH...pi bond.

  2. Vegetation and soils

    Science.gov (United States)

    Burke, M.K.; King, S.L.; Eisenbies, M.H.; Gartner, D.

    2000-01-01

    Intro paragraph: Characterization of bottomland hardwood vegetation in relatively undisturbed forests can provide critical information for developing effective wetland creation and restoration techniques and for assessing the impacts of management and development. Classification is a useful technique in characterizing vegetation because it summarizes complex data sets, assists in hypothesis generation about factors influencing community variation, and helps refine models of community structure. Hierarchical classification of communities is particularly useful for showing relationships among samples (Gauche 1982).

  3. Case report

    African Journals Online (AJOL)

    ebutamanya

    13 oct. 2015 ... la grande lèvre gauche du bord inférieur de la vulve jusqu'au pubis emportant la masse. La dissection du plan était progressive avec une hémostase progressive aux fils Vicryl 2/0 parfois au bistouri électrique. Un rapprochement sous cutané a été fait en deux plans par des points en « U » au Vicryl 3/0 puis ...

  4. NMR study of conformational exchange and double-well proton potential in intramolecular hydrogen bonds in monoanions of succinic acid and derivatives.

    Science.gov (United States)

    Guo, Jing; Tolstoy, Peter M; Koeppe, B; Denisov, Gleb S; Limbach, Hans-Heinrich

    2011-09-08

    We present a (1)H, (2)H, and (13)C NMR study of the monoanions of succinic (1), meso- and rac-dimethylsuccinic (2, 3), and methylsuccinic (4) acids (with tetraalkylammonium as the counterion) dissolved in CDF(3)/CDF(2)Cl at 300-120 K. In all four monoanions, the carboxylic groups are linked by a short intramolecular OHO hydrogen bond revealed by the bridging-proton chemical shift of about 20 ppm. We show that the flexibility of the carbon skeleton allows for two gauche isomers in monoanions 1, 2, and 4, interconverting through experimental energy barriers of 10-15 kcal/mol (the process itself and the energy barrier are also reproduced in MP2/6-311++G** calculations). In 3, one of the gauche forms is absent because of the steric repulsion of the methyl groups. In all four monoanions, the bridging proton is located in a double-well potential and subject, at least to some extent, to proton tautomerism, for which we estimate the two proton positions to be separated by ca. 0.2 Å. In 1 and 3, the proton potential is symmetric. In 2, slowing the conformational interconversion introduces an asymmetry to the proton potential, an effect that might be strong enough even to synchronize the proton tautomerism with the interconversion of the two gauche forms. In 4, the asymmetry of the proton potential is due to the asymmetric substitution. The intramolecular H-bond is likely to remain intact during the interconversion of the gauche forms in 1, 3, and 4, whereas the situation in 2 is less clear.

  5. Mise au point

    African Journals Online (AJOL)

    Le diagnostic de mal de Pott sous occipital associé à une localisation tuberculeuse pulmonaire a été retenu. Le traite- ment anti-tuberculeux a ... The follow-up was 6 years. Discussion : The sub occipital pain Pott localisation was rare. ... 6), associée à une opacité fibreuse rétractile du lobe pulmonaire supérieure gauche.

  6. ‘Every age gets the art it deserves’ ‐ science fiction : history, background and definitions

    OpenAIRE

    Grech, Victor E.; Vassallo, Clare; Callus, Ivan

    2012-01-01

    It would be logical to commence this essay by attempting to identify the approximate locus of SF within the general corpus of literature as perceived by the academy. Fiction might here be seen as having four main categories: canonical fiction (the classics), serious fiction that strives to become canonical, plain fiction (best sellers or general works) and junk fiction: popular and gauche fiction that includes mysteries, thrillers, westerns, romances, fantasy, and SF. It has been argued that ...

  7. Carcinome adenoïde kystique du sinus maxillaire : a propos d'une ...

    African Journals Online (AJOL)

    Le scanner du massif facial avait montré un comblement de la fosse nasale et du sinus maxillaire gauches avec érosion osseuse. Une biopsie de la lésion était en faveur d'un ... A computed tomography performed, showed a filling of left sinonasal cavities with bone invasion. A biopsy made the diagnosis of plémorphic ...

  8. Hydronéphrose géante sur rein ectopique pelvien révélée par un ...

    African Journals Online (AJOL)

    Les auteurs rapportent un cas d'hydronéphrose majeure sur un rein gauche ectopique en position pelvienne, chez un patient de 17 ans, révélé par une occlusion intestinale aigüe. Un drainage premier par néphrostomie per-cutanée écho-guidée a permis de soulager la patient. Le traitement définitif a consisté en une ...

  9. Micro adénome à prolactine à l'âge de la ménopause | Barka | Pan ...

    African Journals Online (AJOL)

    L'examen physique confirme la galactorrhée et la biologie montre une hyperprolactinémie à 2735 mUI /L, FSH = 15,1 UI/L et LH = 4,1UI/L. L'IRM hypophysaire montre un adénome gauche de 8mm. L'évolution sous traitement dopaminergique était marqué par la reprise transitoire des cycles et apparition de bouffées de ...

  10. LE SYNDROME DE POURFOUR DU PETIT : UNE MANIFESTATION ...

    African Journals Online (AJOL)

    cervicale intéressant toute la loge viscérale, la loge vascu- laire gauche et arrivant jusqu'au médiastin supérieur. (flèche). Le reflexe photomoteur direct et consensuel ainsi que l'oculomotricité étaient normaux. Le syndrome infectieux était marqué à la biologie avec une CRP à 330mmol et des globules blancs à 30 000 ...

  11. Case report

    African Journals Online (AJOL)

    abp

    14 avr. 2016 ... Abstract. Le syndrome de Marcus Gunn est un syndrome qui associe un ptosis congénital et une syncinésie mandibulo-palpébrale lors de certains mouvements mandibulaires. Nous rapportons le cas d'un enfant de quatre ans et demi qui présente un ptosis de la paupière gauche qui disparait.

  12. MAQUETTE ORL Décembre 2004

    African Journals Online (AJOL)

    et associé à une érosion du mur de la logette et de lʼos temporal ( Fig1). Lʼimagérie en résonnance magnétique (IRM) confirme la lésion tissulaire du conduit auditif externe gauche éten- due à lʼ lʼoreille moyenne avec envahissement de la paro-. J. TUN ORL - N° 24 JUIN 2010. 87. SARCOME DʼEWING DU ROCHER.

  13. Case report

    African Journals Online (AJOL)

    ebutamanya

    12 oct. 2015 ... l'apparition d'une douleur au niveau de l'hypochondre gauche, une pâleur, une tachycardie avec une ... culots globulaires lors d'une séance d'hémodialyse. Le lendemain, le patient a présenté une ... 6,6% des cas [4] dont la douleur, expliquée essentiellement par l'effraction cutanée et pariétale et surtout ...

  14. l'aspergillose naso-sinusienne dans sa forme pseudo-tumorale

    African Journals Online (AJOL)

    Cependant, cette affection demeure rare chez le sujet immunocompétent. Elle est caractérisée par son caractère invasif pseudotumoral et par la possibilité de complications ... Nous rapportons l'observation d'un patient ayant été suivi et traité pour une ... comblant le sinus maxillaire et la fosse nasale gauche. J. TUN ORL ...

  15. Mise au point

    African Journals Online (AJOL)

    à la lumière de deux observations cliniques, les nouvelles thérapeutiques dans la prise en charge de l'ENb nasosi- nusien. OBSERvATION. Cas 1 : Madame b, 65 ans, sans antécédent particulier, a consulté pour une symptomatologie rhinologique trai- nante depuis plus de deux ans, faite d'obstruction nasale gauche ...

  16. Cas Clinique

    African Journals Online (AJOL)

    du rein droit un volumineux AMLR polaire inférieur de 7 cm sans signe hémorragique ... anatomopathologique définitif a confirmé le diagnostic d'AMLR hémorragique sans signes .... du rein gauche aurait pu être proposée le lendemain de l'admission pour mettre la patiente à l'abri. (relatif) d'une récidive hémorragique et ...

  17. Images in medicine

    African Journals Online (AJOL)

    abp

    16 févr. 2015 ... L'echodoppler (A) et l'angioscanner (B) des troncs supra-aortiques objectivaient un épaississement étendu et fusiforme de l'artère carotide primitive gauche avec une sténose estimée à 60% de l'artère carotide interne droite. L'enquête infectieuse, le bilan immunologique et de thrombophilie étaient ...

  18. PDF provisoire Publié le 15 Mars 2010 Cas clinique, volume 4 ...

    African Journals Online (AJOL)

    cqq1a

    15 mars 2010 ... Un homme âgé de 21 ans a été victime d'une agression avec plaie par coup de couteau au niveau de l'hypochondre gauche ayant occasionné chez lui des épigastralgies intermittentes. Le patient n'a consulté qu'après 20 jours du traumatisme devant la majoration des douleurs. L'examen retrouvait un.

  19. Case report

    African Journals Online (AJOL)

    abp

    15 avr. 2016 ... rapporte un cas rare de SK classique agressive de la main avec une évolution rapide et destructive. Patient et observation nous rapportons le cas d´un patient âgé de 100 ans sans antécédent pathologiques notables qui a consulté pour des lésions pigmentées de la main gauche qui remonte à 20 ans , ...

  20. (1R*,2S*-2-Nitro-1-(4-nitrophenylpropanol

    Directory of Open Access Journals (Sweden)

    Jun-na Zhang

    2012-03-01

    Full Text Available The title compound, C9H10N2O5, presents a racemic mixture of two enantiomeric diastereomers. In the crystal, molecules assemble into zigzag chains parallel to the b axis [C(6 motif] due to the formation of elongated O—H...O(N hydrogen bonds. Of interest is the fact that only the aliphatic nitro group is involved in hydrogen bonding and it adopts a gauche conformation with respect to the OH group.

  1. Les années d’apprentissage des 'Annales révolutionnaires' (1908-1918)

    NARCIS (Netherlands)

    den Boer, P.

    2008-01-01

    Entre le passé radical et l'horizon communiste, voici les années d'apprentissage des 'Annales révolutionnaires'. En rétrospective, des révolutions de gauche eçhouées et des expériences douloureuses de défaite de 1794, de 1830, de 1848, des Quarante-huitards déçus, des Communards tués ou exilés. En

  2. Leiomyome agressif naso-sinusien : a propos d'un cas et revue de ...

    African Journals Online (AJOL)

    Introduction : Les léiomyomes sont des tumeurs bénignes issues des fibres musculaires lisses. La localisation au niveau des cavités nasosinusiennes est très rare. Cas clinique : Il s'agit d'une patiente âgée de 59 ans, qui a consulté pour obstruction nasale et épistaxis gauches. L'endoscopie nasale a montré une formation ...

  3. Le Mélanome Malin Des Cavités Nasosinusiennes : A Propos D\\'un ...

    African Journals Online (AJOL)

    Cas clinique : Les auteurs rapportent un cas de mélanome malin des fosses nasales chez une patiente de 53 ans. Le tableau clinique était dominé par une obstruction nasale gauche associée à une épistaxis intermittente. Le diagnostic a été confirmé par l\\'examen histologique et le traitement a été basé uniquement sur la ...

  4. Tout ce que vous avez appris et oublié en MATHS !

    NARCIS (Netherlands)

    van de Craats, J.; Bosch, R.

    2012-01-01

    Vous ne vous sentez pas sûr de vous en maths ? Vous avez oublié vos formules ? Vous voulez apprendre ou réviser sans professeur ? Ce livre est pour vous ! Essayez d'abord de résoudre les exercices sur la page de gauche. Vous ne savez pas comment vous y prendre ? Regardez la page de droite, vous y

  5. Le syndrome de Tunnel tarsien : à propos d'une observation au ...

    African Journals Online (AJOL)

    Les auteurs présentent un fait clinique d'une douleur subaiguë de la face médiale du pied gauche, explorée par l'imagerie par résonance magnétique, en complément d'une échographie Doppler. Ces explorations ont permis de faire le diagnostic du syndrome de tunnel tarsien par aponévrosite plantaire secondaire à une ...

  6. Images in medicine

    African Journals Online (AJOL)

    ebutamanya

    27 mai 2016 ... Cliniquement elle était fébrile à 38,8°C, bandelettes urinaires (Nitrites, leucocytes +). L'examen mettait en évidence un contacte lombaire gauche douloureux. Le bilan biologique avait objectivé une hyperleucocytose à 22400/mm3, une CRP à 124 mg/l, et l'ECBU a mis en évidence une infection urinaire à ...

  7. Rotational Spectroscopy and Conformational Studies of 4-PENTYNENITRILE, 4-PENTENENITRILE, and Glutaronitrile

    Science.gov (United States)

    Hays, Brian M.; Mehta-Hurt, Deepali; Jawad, Khadija M.; Hernandez-Castillo, Alicia O.; Abeysekera, Chamara; Zhang, Di; Zwier, Timothy S.

    2017-06-01

    The pure rotational spectra of 4-pentynenitrile, 4-pentenenitrile, and glutaronitrile were acquired using chirped pulse Fouirer transform microwave spectroscopy. 4-pentynenitrile and 4-pentenenitrile are the recombination products of two resonance stabilized radicals, propargyl + cyanomethyl or allyl + cyanomethyl, respectively, and are thus anticipated to be significant among the more complex nitriles in Titan's atmosphere. Indeed, these partially unsaturated alkyl cyanides have been found in laboratory analogs of tholins and are also expected to have interesting photochemistry. The optimized structures of all conformers below predicted energies of 500 \\wn were calculated for each molecule. Both of the conformers, trans and gauche, for 4-pentynenitrile have been identified and assigned. Five conformers were assigned in 4-pentenenitrile. The eclipsed conformers, with respect to the vinyl group, dominate the spectrum but some population was found in the syn conformers including the syn-gauche conformer, calculated to be 324 \\wn above the global minimum. The glutaronitrile spectrum contained only the two conformers below 500 \\wn, with reduced amount of the gauche trans conformer. The assigned spectra and structural assignments will be presented.

  8. Study of conformation and dynamic of surfactant molecules in graphite oxide via NMR

    Energy Technology Data Exchange (ETDEWEB)

    Ai, X.Q. [Jiangsu Second Normal University, College of Physics and Electronic Engineering, Nanjing (China); Ma, L.G. [Nanjing Xiaozhuang University, School of Electronic Engineering, Nanjing (China)

    2016-08-15

    The conformation and dynamic of surfactant in graphite oxide (GO) was investigated by solid-state {sup 13}C magic-angle-spinning NMR and {sup 1}H-{sup 13}C cross-polarization/magic-angle-spinning NMR spectra. The conformation ordering of the alkyl chains in the confined system shows strong dependence on its orientation. While the alkyl chains parallel to the GO layer in lateral monolayer arrangement are in gauche conformation in addition to a small amount of all-trans conformation, those with orientation radiating away from the GO in paraffin bilayer arrangement is in all-trans conformation in addition to some gauche conformation even though high-order diffraction peaks appears. NMR results suggest that the least mobile segment is located at the GO-surfactant interface corresponding to the N-methylene group. Further from it, the mobility of the alkyl chain increases. The terminal methyl and N-methyl carbon groups have the highest mobile. The chains in all-trans conformational state are characterized as more rigid than chains with gauche conformation; each segment of the confined alkyl chains with the lateral monolayer arrangement exhibits less mobility as compared to that with the paraffin bilayer arrangement. (orig.)

  9. Gas-Phase Infrared Spectra of Vinyl Selenol and Vinyl Tellurol

    Science.gov (United States)

    Benidar, Abdessamad; Khater, Brahim; Guillemin, Jean-Claude; Gámez, José A.; Yáñez, Manuel

    2009-10-01

    The infrared spectra (3500-500 cm-1) of gaseous vinyl selenol and vinyl tellurol have been recorded at 0.1 cm-1 resolution. For the latter the spectra were obtained at room temperature, but for the former a temperature of -40 °C was required because of the chemical instability of vinyl selenol at room temperature. To compensate the very weak vapor pressure of vinyl tellurol at room temperature, a long optical path up to 136 m was necessary to record its spectrum. B3LYP density functional theory (DFT) calculations have been performed to assign the different absorption bands. Since an unambiguous assignment of the absorption bands requires a precise knowledge on the relative abundance of the syn and gauche rotamers of these compounds, their relative energies and their anharmonic vibrational frequencies were obtained using a very extended Def2-QZVP basis set. Two rotamers, the syn, which is planar, and a nonplanar gauche, were found to be local minima for both compounds. The gauche rotamer presents two degenerate conformers, which differ by the position of the SeH (TeH) hydrogen atom above or below the molecular plane. Our theoretical results are in good agreement with the main features of the experimental spectra. Fundamental bands and some combination bands of vinyl selenol and vinyl tellurol were assigned and compared with those of vinyl alcohol and vinyl thiol, whose spectra had been reported previously in the literature.

  10. Influences of the propyl group on the van der Waals structures of 4-propylaniline complexes with one and two argon atoms studied by electronic and cationic spectroscopy

    International Nuclear Information System (INIS)

    Yang, Zhijun; Gu, Quanli; Trindle, Carl O.; Knee, J. L.

    2015-01-01

    4-propylaniline complexes with one and two argon atoms formed in the molecular beam were studied in the first excited electronic state, S 1 , using resonance enhanced two-photon ionization spectroscopy and in the cation ground state, D 0 , using mass analyzed threshold ionization spectroscopy. The combination of electronic and cationic spectra of the clusters allows two conformations to be identified in both aniline-Ar 1 and aniline-Ar 2 , which are assigned to either the gauche configuration or anti-configuration of 4-propylaniline. The gauche isomer exhibits complex bands shifted 29 cm −1 and 89 cm −1 from the S 1 origin bands and 83 cm −1 and 148 cm −1 from the ionization potential assigned to the Ar 1 and Ar 2 complexes, respectively. For the anti-rotamer, the corresponding shifts actually become nearly additive, 53 cm −1 and 109 cm −1 for the S 1 origin bands, and 61 cm −1 and 125 cm −1 for the ionization potentials. Ab initio calculations provide insights into the influences of the propyl and amino groups on the positions of the argon atoms within the clusters. In addition, the binding energy of one argon with the gauche isomer of 4-propylaniline has been measured to be 550 ± 5 cm −1 in the D 0 state, 496 ± 5 cm −1 in the S 1 state, and 467 ± 5 cm −1 in the neutral ground state, S 0

  11. TCR-contacting residues orientation and HLA-DRβ* binding preference determine long-lasting protective immunity against malaria

    International Nuclear Information System (INIS)

    Alba, Martha P.; Suarez, Carlos F.; Varela, Yahson; Patarroyo, Manuel A.; Bermudez, Adriana; Patarroyo, Manuel E.

    2016-01-01

    Fully-protective, long-lasting, immunological (FPLLI) memory against Plasmodium falciparum malaria regarding immune protection-inducing protein structures (IMPIPS) vaccinated into monkeys previously challenged and re-challenged 60 days later with a lethal Aotus monkey-adapted P. falciparum strain was found to be associated with preferential high binding capacity to HLA-DRβ1* allelic molecules of the major histocompatibility class II (MHC-II), rather than HLA-DRβ3*, β4*, β5* alleles. Complete PPII L 3D structure, a longer distance (26.5 Å ± 1.5 Å) between residues perfectly fitting into HLA-DRβ1*PBR pockets 1 and 9, a gauche − rotamer orientation in p8 TCR-contacting polar residue and a larger volume of polar p2 residues was also found. This data, in association with previously-described p3 and p7 apolar residues having gauche + orientation to form a perfect MHC-II-peptide-TCR complex, determines the stereo-electronic and topochemical characteristics associated with FPLLI immunological memory. - Highlights: • Stereo-electronic and topochemical rules associated with FPLLI immunological memory. • Presence of very high long-lasting antibody titres against Plasmodium falciparum Spz. • Protective memory induction associated with a binding capacity to HLA-DRβ1*. • gauche − rotamer orientation in p8 polar residue is related to is related to immunological memory.

  12. Contribution of High-Pressure-Induced Protein Modifications to the Microenvironment and Functional Properties of Rabbit Meat Sausages.

    Science.gov (United States)

    Xue, Siwen; Yu, Xiaobo; Yang, Huijuan; Xu, Xinglian; Ma, Hanjun; Zhou, Guanghong

    2017-06-01

    Rabbit meat batters were subjected to high pressure (HP, 100 to 300 MPa for 3, 9, or 15 min) to elucidate their effects on proteins structures, the microenvironment, and the resulting functionalities of the subsequently heated products. To determine these effects, we investigated structural and microenvironmental changes using Raman spectroscopy and also expressible moisture content, textural characteristics, and dynamic rheological properties of batters during heating (20 to 80 °C). Untreated samples served as controls. Analysis of specific Raman spectral regions demonstrated that applications of HP to rabbit meat batters tended to induce the transformation of the all-gauche S-S conformation to gauche-gauche-trans in the batter system. HP treatment higher than 100 MPa for 9 min promoted secondary structural rearrangements, and molecular polarity enhancement in the proteins prior to cooking. Also, increases of O-H stretching intensities of rabbit meat sausages were obtained by HP treatment, denoting the strengthening of water-holding capacity. These HP-induced alterations resulted in improved texture and, perhaps, improved juiciness of rabbit meat sausages (P functionalities of gel-type products through modification of meat proteins. © 2017 Institute of Food Technologists®.

  13. Raman spectroscopic analyses of preserved historical specimens of human hair attributed to Robert Stephenson and Sir Isaac Newton.

    Science.gov (United States)

    Edwards, Howell G M; Hassan, Nik F N; Wilson, Andrew S

    2004-10-01

    The Raman spectra of two historical specimens of human hair attributed to the engineer Robert Stephenson and scientist Sir Isaac Newton, preserved in private collections are reported. Comparisons are made with the Raman spectra of modern hair specimens and with hair from archaeological excavations. The hair spectra collected with a laser excitation of 785 nm are of a better quality than those collected using 1064 nm. The historical hair specimens are remarkably well-defined spectroscopically in terms of the amide I vibrational mode and the [small nu](SS), ascribed to a predominantly gauche-gauche-gauche CSSC conformation. The contrast with degraded hair specimens recovered from archaeological excavations is striking. The presence of a weak feature near 2590 cm(-1) in the hair samples attributed to a [small nu](SH) vibration could be indicative of a reduction process operative on the CSSC cystine keratotic linkages and a possible origin of this is bacterial biodegradation identified histologically. This study demonstrates the molecular information available from non-destructive Raman spectroscopic analysis from single hair shafts or small bundles of fibres which complements information available from histological and destructive analytical techniques for rare biological specimens subjected to conservation or curation procedures in museums or private collections.

  14. TCR-contacting residues orientation and HLA-DRβ* binding preference determine long-lasting protective immunity against malaria

    Energy Technology Data Exchange (ETDEWEB)

    Alba, Martha P.; Suarez, Carlos F. [Fundación Instituto de Inmunología de Colombia (FIDIC), Bogotá D. C. (Colombia); Universidad del Rosario, Bogotá D. C. (Colombia); Universidad de Ciencias Aplicadas y Ambientales (UDCA), Bogotá (Colombia); Varela, Yahson [Fundación Instituto de Inmunología de Colombia (FIDIC), Bogotá D. C. (Colombia); Patarroyo, Manuel A.; Bermudez, Adriana [Fundación Instituto de Inmunología de Colombia (FIDIC), Bogotá D. C. (Colombia); Universidad del Rosario, Bogotá D. C. (Colombia); Patarroyo, Manuel E., E-mail: mepatarr@gmail.com [Fundación Instituto de Inmunología de Colombia (FIDIC), Bogotá D. C. (Colombia); Universidad Nacional de Colombia, Bogotá D. C. (Colombia)

    2016-09-02

    Fully-protective, long-lasting, immunological (FPLLI) memory against Plasmodium falciparum malaria regarding immune protection-inducing protein structures (IMPIPS) vaccinated into monkeys previously challenged and re-challenged 60 days later with a lethal Aotus monkey-adapted P. falciparum strain was found to be associated with preferential high binding capacity to HLA-DRβ1* allelic molecules of the major histocompatibility class II (MHC-II), rather than HLA-DRβ3*, β4*, β5* alleles. Complete PPII{sub L} 3D structure, a longer distance (26.5 Å ± 1.5 Å) between residues perfectly fitting into HLA-DRβ1*PBR pockets 1 and 9, a gauche{sup −} rotamer orientation in p8 TCR-contacting polar residue and a larger volume of polar p2 residues was also found. This data, in association with previously-described p3 and p7 apolar residues having gauche{sup +} orientation to form a perfect MHC-II-peptide-TCR complex, determines the stereo-electronic and topochemical characteristics associated with FPLLI immunological memory. - Highlights: • Stereo-electronic and topochemical rules associated with FPLLI immunological memory. • Presence of very high long-lasting antibody titres against Plasmodium falciparum Spz. • Protective memory induction associated with a binding capacity to HLA-DRβ1*. • gauche{sup −} rotamer orientation in p8 polar residue is related to is related to immunological memory.

  15. Fluid Phase Lipid Areas and Bilayer Thicknesses of Commonly Used Phosphatidylcholines as a Function of Temperature

    International Nuclear Information System (INIS)

    Kucerka, Norbert; Nieh, Mu-Ping; Katsaras, John

    2011-01-01

    The structural parameters of fluid phase bilayers composed of phosphatidylcholines with fully saturated, mixed, and branched fatty acid chains, at several temperatures, have been determined by simultaneously analyzing small-angle neutron and X-ray scattering data. Bilayer parameters, such as area per lipid and overall bilayer thickness have been obtained in conjunction with intrabilayer structural parameters (e.g. hydrocarbon region thickness). The results have allowed us to assess the effect of temperature and hydrocarbon chain composition on bilayer structure. For example, we found that for all lipids there is, not surprisingly, an increase in fatty acid chain trans-gauche isomerization with increasing temperature. Moreover, this increase in trans-gauche isomerization scales with fatty acid chain length in mixed chain lipids. However, in the case of lipids with saturated fatty acid chains, trans-gauche isomerization is increasingly tempered by attractive chain-chain van der Waals interactions with increasing chain length. Finally, our results confirm a strong dependence of lipid chain dynamics as a function of double bond position along fatty acid chains.

  16. Kyste anévrismal osseux de la clavicule: à propos d’un cas

    Science.gov (United States)

    Bakkaly, Achraf El; Hanine, Moulay Dris; Amrani, Abdelouahed; Dendane, Anouar; El Alami, Sidi Zouhair Fellouss; Madhi, Tarik El

    2017-01-01

    Le kyste osseux anévrismal est une lésion agressive et destructrice, mais bénigne, des os longs, de la colonne vertébrale ou du bassin, touchant principalement les enfants et les jeunes adultes. Il s’agit cependant d’une véritable tumeur rare. Nous rapportons un cas d’un garçon de 8 ans,présentant une localisation très rare de kyste anévrismal, claviculaire, qui s'est initialement présenté pour une fracture sur os pathologique soit une lésion kystique bénigne. L'enfant a bénéficié d'un traitement radical avec résection complète du kyste situé au niveau de la clavicule droite avec envoi de la pièce opératoire pour étude anatomo-pathologique, confirmant notre diagnostic. L'évolution a été marquée par l'absence de récidive et un bon remodelage osseux sur le plan radiologique. Le traitement radical par résection semble permettre d'éviter la récidive. A travers notre travail, nous voulons mettre le point sur cette affection orthopédique rare en comparant nos résultats avec ceux de la littérature mondiale. PMID:28819536

  17. N,N-Dihexyl-4-[2-(4-nitrophenylvinyl]aniline

    Directory of Open Access Journals (Sweden)

    Dieter Schollmeyer

    2011-06-01

    Full Text Available The title compound, C26H36N2O2, was prepared by Horner olefination of p-dihexylaminobenzaldehyde and diethyl p-nitrobenzylphosphonate. It crystallizes with two independent molecules in the asymmetric unit. Both have similar geometries of the π-systems but the conformations of all hexyl chains are different. Whereas one hexyl chain of the first molecule shows the typical all-anti conformation, the second is arranged in a gauche-anti-gauche-anti conformation with N—C—C—C, C—C—C—C, C—C—C—C and C—C—C—C torsion angles of −65.1 (4, 167.3 (3, 63.3 (4, and 179.4 (3°. One of the hexyl chains in the other molecule has an anti-anti-gauche-anti conformation [N—C—C—C, C—C—C—C, C—C—C—C and C—C—C—C torsion angles = 179.6 (3, −179.8 (3, −68.7 (5 and −178.8 (4°], the other starts with an anti-gauche-gauche sequence. Molecules A and B are composed of five planar subunits. The angle sums around the N atoms are in the range 356 (2–360.0 (2°. Torsion angles between these segments do not exceed 4.9 (4°, except for one of the alkyl chains each [molecule A = 26.2 (4°; molecule B = −6.0 (4°]. The high planarity of the molecules and the short aniline C—N bonds [1.385 (3 Å in molecule A and 1.378 (3 Å in molecule B] indicate a strong electronic coupling through the stilbene unit. One methylene group is disordered over two positions with an occupancy ratio of 0.72:0.28.

  18. The vicinal difluoro motif: The synthesis and conformation of erythro- and threo- diastereoisomers of 1,2-difluorodiphenylethanes, 2,3-difluorosuccinic acids and their derivatives

    Directory of Open Access Journals (Sweden)

    Schüler Martin

    2006-10-01

    Full Text Available Abstract Background It is well established that vicinal fluorines (RCHF-CHFR prefer to adopt a gauche rather than an anti conformation when placed along aliphatic chains. This has been particularly recognised for 1,2-difluoroethane and extends to 2,3-difluorobutane and longer alkyl chains. It follows in these latter cases that if erythro and threo vicinal difluorinated stereoisomers are compared, they will adopt different overall conformations if the fluorines prefer to be gauche in each case. This concept is explored in this paper with erythro- and threo- diastereoisomers of 2,3-difluorosuccinates. Results A synthetic route to 2,3-difluorosuccinates has been developed through erythro- and threo- 1,2-difluoro-1,2-diphenylethane which involved the oxidation of the aryl rings to generate the corresponding 2,3-difluorosuccinic acids. Ester and amide derivatives of the erythro- and threo- 2,3-difluorosuccinic acids were then prepared. The solid and solution state conformation of these compounds was assessed by X-ray crystallography and NMR. Ab initio calculations were also carried out to model the conformation of erythro- and threo- 1,2-difluoro-1,2-diphenylethane as these differed from the 2,3-difluorosuccinates. Conclusion In general the overall chain conformations of the 2,3-difluorosuccinates diastereoisomers were found to be influenced by the fluorine gauche effect. The study highlights the prospects of utilising the vicinal difluorine motif (RCHF-CHFR as a tool for influencing the conformation of performance organic molecules and particularly tuning conformation by selecting specific diastereoisomers (erythro or threo.

  19. Influences of the propyl group on the van der Waals structures of 4-propylaniline complexes with one and two argon atoms studied by electronic and cationic spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Zhijun [School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang, Henan 453003 (China); Gu, Quanli [School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang, Henan 453003 (China); Department of Chemistry, University of Oklahoma, Norman, Oklahoma 73019 (United States); Trindle, Carl O., E-mail: cot@virginia.edu [Chemistry Department, University of Virginia, Charlottesville, Virginia 22904 (United States); Knee, J. L., E-mail: jknee@wesleyan.edu [Chemistry Department, Wesleyan University, Middletown, Connecticut 06459 (United States)

    2015-07-21

    4-propylaniline complexes with one and two argon atoms formed in the molecular beam were studied in the first excited electronic state, S{sub 1}, using resonance enhanced two-photon ionization spectroscopy and in the cation ground state, D{sub 0}, using mass analyzed threshold ionization spectroscopy. The combination of electronic and cationic spectra of the clusters allows two conformations to be identified in both aniline-Ar{sub 1} and aniline-Ar{sub 2}, which are assigned to either the gauche configuration or anti-configuration of 4-propylaniline. The gauche isomer exhibits complex bands shifted 29 cm{sup −1} and 89 cm{sup −1} from the S{sub 1} origin bands and 83 cm{sup −1} and 148 cm{sup −1} from the ionization potential assigned to the Ar{sub 1} and Ar{sub 2} complexes, respectively. For the anti-rotamer, the corresponding shifts actually become nearly additive, 53 cm{sup −1} and 109 cm{sup −1} for the S{sub 1} origin bands, and 61 cm{sup −1} and 125 cm{sup −1} for the ionization potentials. Ab initio calculations provide insights into the influences of the propyl and amino groups on the positions of the argon atoms within the clusters. In addition, the binding energy of one argon with the gauche isomer of 4-propylaniline has been measured to be 550 ± 5 cm{sup −1} in the D{sub 0} state, 496 ± 5 cm{sup −1} in the S{sub 1} state, and 467 ± 5 cm{sup −1} in the neutral ground state, S{sub 0}.

  20. Raman spectroscopic study of leptospiral glycolipoprotein

    Science.gov (United States)

    Bao, PeiDi; Bao, Lang; Huang, TianQuan; Liu, XinMing

    1998-04-01

    The Raman scattering spectra of two different samples of Leptospiral Glycoipoprotein (GLP-1 and GLP-2) which have different toxic effects have been obtained and investigated. Leptospirosis is one of the most harmful zoonosis. It is a serious public health issue in some area of Sichusan province. The two samples offer different structural informations of GLP molecules, it would be important to find the difference in contents, structures and the amino acid side - chains environment of the molecules between the two samples of GLP for understanding the different toxic effects. The intense Am I at 1651 cm-1 and weak Am III at 1283 cm-1 show that GLP-1 has a predominantly (alpha) -helix secondary structure. The intense Am I at 1674 cm-1 and intense Am III at 1246 cm-1 show that the conformation of GLP-2 has a high content of (Beta) - sheet and a low content of random - coil secondary structure. Strong Raman scattering occurs in the range 920- 980 cm-1, belong to the C-COO vibration and the stretching of the peptide backbone. The molecules of GLP-1 has trans-gauche-trans configuration of the C-S-S-C-C linkage and the molecules of GLP-2 has trans-gauche-gauche configuration of the C-C-S-S-C-C linkage. The intensity ratio of the two tyrosine liens at 830 cm-1 and 850 cm-1 is 1.1 and 1.23, indicate their tyrosine reduces environment respectively. Other side-chain environment in the two samples were discussed.

  1. Conformational dynamics of dry lamellar crystals of sugar based lipids: an atomistic simulation study.

    Directory of Open Access Journals (Sweden)

    Vijayan ManickamAchari

    Full Text Available The rational design of a glycolipid application (e.g. drug delivery with a tailored property depends on the detailed understanding of its structure and dynamics. Because of the complexity of sugar stereochemistry, we have undertaken a simulation study on the conformational dynamics of a set of synthetic glycosides with different sugar groups and chain design, namely dodecyl β-maltoside, dodecyl β-cellobioside, dodecyl β-isomaltoside and a C12C10 branched β-maltoside under anhydrous conditions. We examined the chain structure in detail, including the chain packing, gauche/trans conformations and chain tilting. In addition, we also investigated the rotational dynamics of the headgroup and alkyl chains. Monoalkylated glycosides possess a small amount of gauche conformers (∼20% in the hydrophobic region of the lamellar crystal (LC phase. In contrast, the branched chain glycolipid in the fluid Lα phase has a high gauche population of up to ∼40%. Rotational diffusion analysis reveals that the carbons closest to the headgroup have the highest correlation times. Furthermore, its value depends on sugar type, where the rotational dynamics of an isomaltose was found to be 11-15% and more restrained near the sugar, possibly due to the chain disorder and partial inter-digitation compared to the other monoalkylated lipids. Intriguingly, the present simulation demonstrates the chain from the branched glycolipid bilayer has the ability to enter into the hydrophilic region. This interesting feature of the anhydrous glycolipid bilayer simulation appears to arise from a combination of lipid crowding and the amphoteric nature of the sugar headgroups.

  2. African Journal of Neurological Sciences - 2009 Vol. 28 No 1

    African Journals Online (AJOL)

    L'examen neurologique a objectivé une aphasie de Wernicke sans déficit neurologique associé. L'état général conservé, apyrétique et le bilan biologique était normal. La TDM et l'IRM cérébrales ont montrés une lésion temporale gauche (fig.2). Le patient a été opéré ayant eu une exérèse complète d'une lésion abcédée ...

  3. 1-(3-Bromopropylindoline-2,3-dione

    Directory of Open Access Journals (Sweden)

    Fatima Zahrae Qachchachi

    2016-04-01

    Full Text Available In the title compound, C11H10BrNO2, the indoline ring system has an r.m.s. deviation of 0.026 Å. The side chain (including the Br atom has a trans–gauche conformation, as indicated by the N—C—C—C and C—C—C—Br torsion angles of −177.5 (3 and 68.1 (3°, respectively. In the crystal, molecules are linked by weak C—H...O hydrogen bonds, forming a three-dimensional network.

  4. Fabiola Gianotti (left) and President of CERN Council Agnieszka Zalewska sign Gianotti's contract as the next Director-General of CERN.

    CERN Multimedia

    Brice, Maximilien

    2014-01-01

    Fabiola Gianotti (left) and President of CERN Council Agnieszka Zalewska sign Gianotti's contract as the next Director-General of CERN. Gianotti's five-year mandate will start on 1 January 2016 (Image: Maximilien Brice/CERN) Mme Fabiola Gianotti (à gauche) et la Présidente du Conseil du CERN, Mme Agnieszka Zalewska, signent le contrat de Mme Gianotti, prochaine directrice générale du CERN. Le mandat de cinq ans de Mme Gianotti débutera le 1er janvier 2016 (Image : M Brice)

  5. Case report

    African Journals Online (AJOL)

    abp

    21 mars 2014 ... LaTDM cérébrale mettait en évidence un processus tumoral discrètement dense, se rehaussant massivement de façon hétérogène par le produit de contraste, mesurant 70×60mm de diamètre au niveau du cervelet de part et d'autre de la ligne médiane (Figure 1), étendu au lobe occipital gauche avec une.

  6. Evaluation of innovative motorcycle headlight configurations: effect on car drivers’ perception of motorcyles’ motion

    OpenAIRE

    CAVALLO, Viola; RANCHET, Maud; PINTO, Maria; ESPIE, Stéphane; VIENNE, Fabrice; DANG, Nguyen-Thong

    2014-01-01

    L'expérimentation présentée étudie l'effet de 4 configurations de feux avant de moto sur l'acceptation de créneaux temporels par des automobilistes lorsqu'ils tournent à gauche face à des motocycles. The most frequent cause of motorcycle accidents involves another vehicle violating the motorcycle's right-of-way at an intersection. In addition to detection errors, the misperception of the approaching motorcycle's speed and time-to-arrival is another driver error that may account for these a...

  7. Improving car drivers' perception of motorcycle motion through innovative headlight configurations.

    OpenAIRE

    CAVALLO, Viola; RANCHET, Maud; PINTO, Maria; ESPIE, Stéphane; VIENNE, Fabrice; DANG, Nguyen-Thong

    2015-01-01

    L'article présente une expérimentation sur simulateur de conduite qui examine l'effet de différentes configurations de feux avant de moto sur les créneaux temporels acceptés par des automobilistes lorsqu'ils tournent à gauche face à à des motocycles. L'impact des configurations de feux est évalué dans différentes conditions d'illumination (jour, crépuscule, nuit). The most frequent cause of motorcycle accidents occurs when another vehicle violates the motorcycle's right-of-way at an inters...

  8. Raman spectroscopic study of reaction dynamics

    Science.gov (United States)

    MacPhail, R. A.

    1990-12-01

    The Raman spectra of reacting molecules in liquids can yield information about various aspects of the reaction dynamics. The author discusses the analysis of Raman spectra for three prototypical unimolecular reactions, the rotational isomerization of n-butane and 1,2-difluoroethane, and the barrierless exchange of axial and equatorial hydrogens in cyclopentane via pseudorotation. In the first two cases the spectra are sensitive to torsional oscillations of the gauche conformer, and yield estimates of the torsional solvent friction. In the case of cyclopentane, the spectra can be used to discriminate between different stochastic models of the pseudorotation dynamics, and to determine the relevant friction coefficients.

  9. André Blumel, un itinéraire sioniste à la croisée des chemins

    OpenAIRE

    Lafon, François

    2009-01-01

    Cet article envisage à travers l’itinéraire sioniste d’André Blumel les relations entre la gauche française et l’État d’Israël. Proche de Léon Blum, dont il fut directeur de Cabinet durant le Front populaire, mais se rapprochant progressivement des communistes, Blumel demeura jusqu’en 1966 une figure clefs des milieux sionistes français. Conciliant divers engagements – pourtant apparemment contradictoires – son parcours permet de comprendre la complexité des liens et des conflits qui caractér...

  10. Images in medicine

    African Journals Online (AJOL)

    abp

    1 oct. 2015 ... maxillaires et un larmoiement. L'inspection a montré une hémiface fortement déformée par une tuméfaction lisse faisant huit centimètres de grand axe (A,B), de consistance dure à la palpation. La rhinoscopie antérieure a révélé dans la cavité nasale gauche une tumeur lisse, blanchâtre, non hémorragique ...

  11. (S-Methyl 2-benzamido-3-(3,4-dimethoxyphenylpropanoate

    Directory of Open Access Journals (Sweden)

    Tricia Naicker

    2012-01-01

    Full Text Available The dimethoxypbenzene ring in the title compound, C19H21NO5, is gauche to the amide group and anti to the ester group. The chirality was confirmed to be S from two-dimensional NMR spectroscopy. In the crystal, N—H...O and C—H...O hydrogen bonds and several short-contact interactions (2.07–3.45 Å create chains parallel to [110]. The phenyl ring is disordered over two orientations in a 0.54 (2:0.46 (2 ratio.

  12. CERN Multimedia

    Jean-Claude Gadmer

    2012-01-01

    Les orateurs de gauche à droite: - M. Fabrice Lelouvier, Directeur d’Ubifrance Suisse - S. Exc. M. Nicolas Niemtchinow, Ambassadeur, Représentant permanent de la République française auprès de l’Office des Nations Unies et des autres organisations internationales à Genève - Prof. Rolf Heuer, Directeur général du CERN - M. Christophe Hercelin, RS Components Responsable Marketing Electronics Europe, Sponsor de l'évènement.

  13. Intramolecular diffusive motion in alkane monolayers studied by high-resolution quasielastic neutron scattering and molecular dynamics simulations

    DEFF Research Database (Denmark)

    Hansen, Flemming Yssing; Criswell, L.; Fuhrmann, D

    2004-01-01

    Molecular dynamics simulations of a tetracosane (n-C24H50) monolayer adsorbed on a graphite basal-plane surface show that there are diffusive motions associated with the creation and annihilation of gauche defects occurring on a time scale of similar to0.1-4 ns. We present evidence...... that these relatively slow motions are observable by high-energy-resolution quasielastic neutron scattering (QNS) thus demonstrating QNS as a technique, complementary to nuclear magnetic resonance, for studying conformational dynamics on a nanosecond time scale in molecular monolayers....

  14. N-[3-(Benzenesulfonamidopropyl]benzenesulfonamide

    Directory of Open Access Journals (Sweden)

    Tahir Ali Sheikh

    2011-07-01

    Full Text Available In the title compound, C15H18N2O4S2, the dihedral angle between the aromatic rings is 71.8 (2°. The conformation of the central N—C—C—C—N fragment is gauche–gauche [torsion angles = 72.5 (5 and 65.7 (5°]. Both N atoms adopt pyramidal geometries. In the crystal, molecules are linked by N—H...O hydrogen bonds, generating (001 sheets, and weak C—H...O interactions consolidate the packing.

  15. N-(2,5-Dimethylphenyl-4-methylbenzenesulfonamide

    Directory of Open Access Journals (Sweden)

    B. Thimme Gowda

    2010-01-01

    Full Text Available In the crystal structure of the title compound, C15H17NO2S, the conformation of the N—C bond in the C—SO2—NH—C segment has gauche torsions with respect to the S=O bonds. The molecule is bent at the S atom with a C—SO2—NH—C torsion angle of −61.0 (2°. The dihedral angle between the two aromatic rings is 49.4 (1°. The crystal structure features inversion-related dimers linked by pairs of N—H...O hydrogen bonds.

  16. Ethane-1,1,2-trisphosphonic acid hemihydrate.

    Science.gov (United States)

    Delain-Bioton, Lise; Lohier, Jean François; Villemin, Didier; Sopková-de Oliveira Santos, Jana; Hix, Gary; Jaffrès, Paul Alain

    2008-02-01

    Ethane-1,1,2-trisphosphonic acid crystallizes as a hemihydrate, C(2)H(9)O(9)P(3).0.5H(2)O, in which the water O atom lies on an inversion centre in the space group P2(1)/c. The acid component, which contains a short but noncentred O-H...O hydrogen bond, adopts a gauche conformation. The acid components are linked by an extensive series of O-H...O hydrogen bonds to form layers, which are linked into pairs by the water molecules.

  17. Tumeurs des deux surrénales. A propos d'un cas | El Baghouli ...

    African Journals Online (AJOL)

    L'examen anatomopathologique a révélé la coexistence d'un phéochromocytome sur la pièce de surrénalectomie droite et d'un carcinome corticosurrénalien sur la pièce de surrénalectomie gauche, ce qui était imprévu. Les suites opératoires ont été bonnes, sans récidive, avec un recul de 4 ans. A la lumière de cette ...

  18. CERN Document Server

    Maximilien Brice

    2010-01-01

    Procèdent à la signature, de gauche à droite: J.-B. Mattéi, Ambassadeur, Représentant permanent de la France auprès de Nations Unies à Genève et des Organisations internationales en Suisse; R. Heuer, Directeur général du CERN; V. Zellweger, Ambassadeur, Directeur de la Direction du droit international public, Département fédéral des affaires étrangères (DFAE, CH. Visite du hall de test des aimants supraconducteurs du LHC avec le Chef du département Technologie F. Bordry.

  19. Spectroscopic Signatures and Structural Motifs of Dopamine: a Computational Study

    Science.gov (United States)

    Srivastava, Santosh Kumar; Singh, Vipin Bahadur

    2016-06-01

    Dopamine (DA) is an essential neurotransmitter in the central nervous system and it plays integral role in numerous brain functions including behaviour, cognition, emotion, working memory and associated learning. In the present work the conformational landscapes of neutral and protonated dopamine have been investigated in the gas phase and in aqueous solution by MP2 and DFT (M06-2X, ωB97X-D, B3LYP and B3LYP-D3) methods. Twenty lowest energy structures of neutral DA were subjected to geometry optimization and the gauche conformer, GIa, was found to be the lowest gas phase structure at the each level of theory in agreement with the experimental rotational spectroscopy. All folded gauche conformers (GI) where lone electron pair of the NH2 group is directed towards the π system of the aromatic ring ( 'non up' ) are found more stable in the gas phase. While in aqueous solution, all those gauche conformers (GII) where lone electron pair of the NH2 group is directed opposite from the π system of the aromatic ring ('up' structures) are stabilized significantly.Nine lowest energy structures, protonated at the amino group, are optimized at the same MP2/aug-cc-pVDZ level of theory. In the most stable gauche structures, g-1 and g+1, mainly electrostatic cation - π interaction is further stabilized by significant dispersion forces as predicted by the substantial differences between the DFT and dispersion corrected DFT-D3 calculations. In aqueous environment the intra-molecular cation- π distance in g-1 and g+1 isomers, slightly increases compared to the gas phase and the magnitude of the cation- π interaction is reduced relative to the gas phase, because solvation of the cation decreases its interaction energy with the π face of aromatic system. The IR intensity of the bound N-H+ stretching mode provides characteristic 'IR spectroscopic signatures' which can reflect the strength of cation- π interaction energy. The CC2 lowest lying S1 ( 1ππ* ) excited state of neutral

  20. Structure and phase transitions of monolayers of intermediate-length n-alkanes on graphite studied by neutron diffraction and molecular dynamics simulation

    DEFF Research Database (Denmark)

    Diama, A.; Matthies, B.; Herwig, K. W.

    2009-01-01

    measurements indicate that the two monolayer films differ principally in the transition temperatures between phases. At the lowest temperatures, both C24 and C32 form a crystalline monolayer phase with a rectangular-centered (RC) structure. The two sublattices of the RC structure each consists of parallel rows...... show evidence of broadening of the lamella boundaries as a result of molecules diffusing parallel to their long axis. At still higher temperatures, they indicate that the introduction of gauche defects into the alkane chains drives a melting transition to a monolayer fluid phase as reported previously...

  1. [Study of selegiline and related compounds with x-ray diffraction].

    Science.gov (United States)

    Simon, K; Böcskei, Z; Török, Z

    1992-09-01

    Selegiline and its parent compounds were studied by X-ray diffraction. It was established that the racemates of primary and secondary amines (p-fluoro-amphetamine, methamphetamine, p-fluoro-methamphetamine) hydrochloride do not form racemic compounds but crystalline as conglomerates, at the same time tertiary amines like selegiline and p-fluoro-selegiline hydrochlorides do. The crystalline structure of five enantiomeric hydrochlorides were determined, the CPhe-C-C-N torsion angle is anti-periplanar in all cases but in p-fluoro-amphetamine where it is gauche.

  2. Case report

    African Journals Online (AJOL)

    abp

    5 janv. 2015 ... était victime d'une agression par coup de couteau à la région péri- ombilicale. À son admission, elle était consciente, stable sur le plan hémodynamique et respiratoire. Une plaie pénétrante de 2 cm en péri-ombilicale gauche a été constaté avec défense abdominale généralisée. L'examen neurologique a ...

  3. sommaire N°13

    African Journals Online (AJOL)

    une agression par arme blanche qui s'est présenté aux urgences avec le couteau fiché dans la région temporale. oBSERVAtIoN. Un homme âgé de 37 ans est victime d'une agression par un coup de couteau qui est resté fiché dans la région tem- porale gauche (figure 1,2). Le patient était par ailleurs conscient bien orienté ...

  4. Millimetre-wave spectrum of anti-13C1 and 13C2 isotopologues of ethanol

    International Nuclear Information System (INIS)

    Bouchez, Aurelia; Walters, Adam; Müller, Holger S.P.; Ordu, Matthias; Lewen, Frank; Koerber, Monika; Bottinelli, Sandrine; Endres, Christian P.; Schlemmer, Stephan

    2012-01-01

    The rotational spectra of the two monosubstituted 13 C isotopologues of the anti conformer of ethanol have been measured between 80-800 GHz using three different spectrometers at the Cologne Laboratory Astrophysics group. The dataset was constrained for fitting with a standard Watson-S reduction Hamiltonian by rejecting transitions from high-lying states showing significant perturbation with the gauche states and by averaging some small methyl torsional splits. This treatment is compatible with the needs for a first astrophysical research for which an appropriate set of predictions is given.

  5. Case report

    African Journals Online (AJOL)

    abp

    21 sept. 2017 ... L'examen du segment antérieur était sans particularité au niveau des deux yeux, le fond d'œil était normal à droite, alors qu'il a objectivé au niveau de l'œil gauche une lésion atrophique en plein macula, en forme de cratère, de quatre diamètres papillaires à peu près, bien circonscrite avec présence de.

  6. la tumeur de warthin de la parotide : a propos de 11 cas

    African Journals Online (AJOL)

    9 mai 2013 ... Nodule de densité tissulaire à contours nets du pôle infé- rieur de la glande parotide gauche avec prise de contraste hétérogène. L'iRM réalisée pour 3 autres patients a posé le diagnos- tic de tumeur bénigne de la parotide dans tous les cas en montrant des tumeurs aux contours réguliers et biens définis.

  7. Nanocylindrical confinement imparts highest structural order in molecular self-assembly of organophosphonates on aluminum oxide.

    Science.gov (United States)

    Pathak, Anshuma; Bora, Achyut; Braunschweig, Björn; Meltzer, Christian; Yan, Hongdan; Lemmens, Peter; Daum, Winfried; Schwartz, Jeffrey; Tornow, Marc

    2017-05-18

    We report the impact of geometrical constraint on intramolecular interactions in self-assembled monolayers (SAMs) of alkylphosphonates grown on anodically oxidized aluminum (AAO). Molecular order in these films was determined by sum frequency generation (SFG) spectroscopy, a more sensitive measure of order than infrared absorption spectroscopy. Using SFG we show that films grown on AAO are, within detection limits, nearly perfectly ordered in an all-trans alkyl chain configuration. In marked contrast, films formed on planar, plasma-oxidized aluminum oxide or α-Al 2 O 3 (0001) are replete with gauche defects. We attribute these differences to the nanocylindrical structure of AAO, which enforces molecular confinement.

  8. The interaction of circularly polarised electromagnetic waves with a plasma; Interaction d'ondes electromagnetiques a polarisation circulaire avec un plasma

    Energy Technology Data Exchange (ETDEWEB)

    Consoli, T; Legardeur, R; Slama, L [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1961-07-01

    The interaction of left and right handed circularly polarised waves with a plasma are studied. The individual trajectories of charges of both signs are traced with a analogical simulator. Applications to plasma heating and diagnostic are deduced. (author) [French] On etudie l'interaction des ondes a polarisation circulaire droite ou gauche avec un plasma. Les trajectoires individuelles des charges sont tracees a l'aide d'un dispositif analogique. On en deduit les applications au chauffage d'un plasma et a la mesure de ses parametres caracteristiques. (auteur)

  9. Sum frequency generation spectroscopy of tetraalkylphosphonium ionic liquids at the air-liquid interface

    Science.gov (United States)

    Peñalber-Johnstone, Chariz; Adamová, Gabriela; Plechkova, Natalia V.; Bahrami, Maryam; Ghaed-Sharaf, Tahereh; Ghatee, Mohammad Hadi; Seddon, Kenneth R.; Baldelli, Steven

    2018-05-01

    Sum frequency generation (SFG) spectroscopy is a nonlinear vibrational spectroscopic technique used in the study of interfaces, due to its unique ability to distinguish surface molecules that have preferential ordering compared to the isotropic bulk. Here, a series of alkyltrioctylphosphonium chloride ionic liquids, systematically varied by cation structure, were characterized at the air-liquid interface by SFG. The effect on surface structure resulting from molecular variation (i.e., addition of cyano- and methoxy-functional groups) of the cation alkyl chain was investigated. SFG spectra in the C—H stretching region (2750-3100 cm-1) for [P8 8 8 n][Cl], where n = 4, 5, 8, 10, 12, or 14, showed characteristic changes as the alkyl chain length was increased. Spectral profiles for n = 4, 5, 8, or 10 appeared similar; however, when the fourth alkyl chain was sufficiently long (as in the case of n = 12 or n = 14), abrupt changes occurred in the spectra. Molecular dynamics (MD) simulation of a slab of each ionic liquid (with n = 8, 10, or 12) confirmed gauche defects, with enhancement for the long alkyl chain and an abrupt increase of gauche occurrence from n = 8 to n = 10. A comparison of the tilt angle distribution from the simulation and the SFG analysis show a broad distribution of angles. Using experimental SFG spectra in conjunction with MD simulations, a comprehensive molecular picture at the surface of this unique class of liquids is presented.

  10. High resolution spectroscopy of 1,2-difluoroethane in a molecular beam: A case study of vibrational mode-coupling

    Science.gov (United States)

    Mork, Steven W.; Miller, C. Cameron; Philips, Laura A.

    1992-09-01

    The high resolution infrared spectrum of 1,2-difluoroethane (DFE) in a molecular beam has been obtained over the 2978-2996 cm-1 spectral region. This region corresponds to the symmetric combination of asymmetric C-H stretches in DFE. Observed rotational fine structure indicates that this C-H stretch is undergoing vibrational mode coupling to a single dark mode. The dark mode is split by approximately 19 cm-1 due to tunneling between the two identical gauche conformers. The mechanism of the coupling is largely anharmonic with a minor component of B/C plane Coriolis coupling. Effects of centrifugal distortion along the molecular A-axis are also observed. Analysis of the fine structure identifies the dark state as being composed of C-C torsion, CCF bend, and CH2 rock. Coupling between the C-H stretches and the C-C torsion is of particular interest because DFE has been observed to undergo vibrationally induced isomerization from the gauche to trans conformer upon excitation of the C-H stretch.

  11. Frequency-dependent solvent friction and torsional damping in liquid 1,2-difluoroethane

    Science.gov (United States)

    MacPhail, Richard A.; Monroe, Frances C.

    1991-04-01

    We have used Raman spectroscopy to study the torsional dynamics, rotational dynamics, and conformational solvation energy of liquid 1,2-difluoroethane. From the Raman intensities, we obtain Δ H(g-t) = -2.4±0.1 kcal/mol, indicating strong dipolar solvation of the gauche conformer. We analyze the Raman linewidths of the CCF bending bands to obtain the zero-frequency torsional damping coefficient or well friction for the gauche conformer, and from the linewidth of the torsion band we obtain the friction evaluated at the torsional frequency. The zero-frequency well friction shows deviations from hydrodynamic behavior reminiscent of those observed for barrier friction, whereas the high-frequency friction is considerably smaller in magnitude and independent of temperature and viscosity. The zero-frequency torsional friction correlates linearly with the rotational friction. It is argued that the small amplitude of the torsional fluctuations emphasizes the short distance, or high wavevector components of the solvent friction. Dielectric friction apparently does not contribute to the torsional friction at the observed frequencies.

  12. Early structural development in melt-quenched polymer PTT from atomistic molecular dynamic simulations

    Science.gov (United States)

    Hsieh, Min-Kang; Lin, Shiang-Tai

    2009-12-01

    Molecular dynamics simulations are performed to study the initial structural development in poly(trimethylene terephthalate) (PTT) when quenched below its melting point. The development of local ordering has been observed in our simulations. The thermal properties, such as the glass transition temperature (Tg) and the melting temperature (Tm), determined from our simulations are in reasonable agreement with experimental values. It is found that, between these two temperatures, the number of local structures quickly increases during the thermal relaxation period soon after the system is quenched and starts to fluctuate afterwards. The formation and development of local structures is found to be driven mainly by the torsional and van der Waals forces and follows the classical nucleation-growth mechanism. The variation of local structures' fraction with temperature exhibits a maximum between Tg and Tm, resembling the temperature dependence of the crystallization rate for most polymers. In addition, the backbone torsion distribution for segments within the local structures preferentially reorganizes to the trans-gauche-gauche-trans (t-g-g-t) conformation, the same as that in the crystalline state. As a consequence, we believe that such local structural ordering could be the baby nuclei that have been suggested to form in the early stage of polymer crystallization.

  13. Hernie de Spiegel: a propos d’un cas

    Directory of Open Access Journals (Sweden)

    Karim Ibn Majdoub Hassani

    2010-02-01

    Full Text Available La hernie de Spiegel ou hernie ventrale latérale est une déhiscence inhabituelle apparaissant sur la ligne ou fascia semi-lunaire de Spiegel. C’est une entité clinique rare, représente 0.10 à 1 pourcent des hernies. Aussi, nous a-t-il paru opportun de rapporter ce cas colligé dans le service de chirurgie B du CHU Hassan II de Fès. Nous rapportons l’observation d’une patiente âgée de 60 ans, sans antécédent particulier qui présentais une tuméfaction para ombilicale gauche augmentant progressivement de volume, Une hernie de Spiegel a été suspectée à l’examen clinique, et le diagnostic d’éventration antérolatérale gauche a été retenu à la tomodensitométrie abdominale. Une cure de la hernie par plaque de prolène a été réalisée et les suites opératoires étaient simples. La hernie de Spiegel est une affection rare, son diagnostic clinique peut être difficile. Elle est asymptomatique dans 90 pourcent des cas et Son diagnostic positif est radiologique. Le risque d’étranglement non négligeable impose un traitement chirurgical une fois le diagnostic est confirmé.

  14. L’infarctus du myocarde du jeune adulte -Analyse rétrospective des cas colligés au CHU de Dakar

    Directory of Open Access Journals (Sweden)

    Nobila Valentin Yameogo

    2010-09-01

    Full Text Available Les données relatives à l’infarctus du myocarde chez le jeune adulte sont rares en Afrique noir. Nous rapportons une série rétrospective de 14 cas d’infarctus du myocarde chez l’adulte jeune noir africain. Pour analyser les caractéristiques épidémiologiques, cliniques, électriques, échographiques, biologiques, thérapeutiques et évolutives de l’infarctus aigu du myocarde chez le jeune adulte nous avons étudié de manière rétrospective les dossiers médicaux d’une série consécutive des patients admis entre Janvier 2003 et Décembre 2008 pour prise en charge d’infarctus aigu du myocarde. Quatre-vingt quatre (84 cas d’infarctus du myocarde ont été pris en charge durant la période d’étude ,14 patients (16,6% avaient un âge inférieur ou égal à 40 ans. L’âge moyen était de 34 +ou-5ans (extrêmes 27ans et 40 ans. Les facteurs de risque cardio-vasculaire étaient dominés par le sexe masculin (n=11, la dyslipidémie (n=7 et le tabagisme par cigarette (n=6. La contraception orale était absente chez le 1/3 des patients. Le délai moyen d’admission était tardif (15 plus ou moins 4 heures. L’IDM était antérieur dans la moitié des cas. L’acide acétylsalicylique, les inhibiteurs de l’enzyme de conversion Les bétabloquants et les statines étaient les médicaments les plus prescrits. La thrombolyse et l’angioplastie étaient respectivement réalisées chez 3 patients et 0 patient. 4 cas d’insuffisance cardiaque, 2 cas de bloc atrio-ventriculaire complet et 1 cas de décès étaient les principales complications. L’infarctus du myocarde concerne également le sujet jeune noir africain. Les facteurs de risque sont essentiellement représentés par le sexe, la dyslipidémie, le tabagisme et la contraception orale.

  15. The Free Jet Microwave Spectrum of 2-PHENYLETHYLAMINE-WATER

    Science.gov (United States)

    Melandri, Sonia; Giuliano, B. Michela; Maris, Assimo; Caminati, Walther

    2009-06-01

    2-Phenylethylamine (PEA) is the parent structure for a variety of important compounds including dopamine, tyrosine, anphetamine and adrenaline. Due to the flexibility of the side chain, the conformational hypersurface of the isolated molecule contains several minima at relatively low energy. The conformational surface was studied by various spectroscopic and theoretical techniques and four of the five stable conformers were detected. The most stable conformers observed in isolated conditions are those in which the methylene side chain is folded into a gauche structure and the amino hydrogen is oriented towards the aromatic ring to form a weakly hydrogen bonded structure, while in the less stable conformers the amino group is in the anti position, thus the energy difference between the gauche and anti conformers (ca 4 kJ mol^{-1}) represents the energy associated with this weak interaction. Since bioactive molecules can be found in different environments including aqueous media and rotational spectroscopy coupled with high level ab initio calculations gives the most detailed structural picture, we studied the free jet microwave spectrum of the adducts formed between PEA and water in the region 60-78 GHz. The dominant spectrum is that of the 1:1 adduct of PEA and water where PEA is in its most stable gauche conformation and the water molecole is bound to the nitrogen lone pair. The orientation of the water molecole is such that the oxygen atom is closest (ca 2.5 Å) and equidistant from the ring and chain hydrogen atoms. The experimental data were complemented by ab initio calculations at the MP2/6311++G** level of theory; several stable conformations of the PEA-W have been characterized and the observed structure corresponds to the global minimum. The bonding of water seems to affect only slightly the structure of isolated PEA and the main structural parameters of the flexible amino side chain remain basically unaltered. Some lines still remain unassigned in the

  16. Comparison of the one-electron oxidations of CO-bridged vs unbridged bimetallic complexes: Electron-transfer chemistry of Os2Cp2(CO)4 and Os2Cp∗2(μ-CO)2(CO)2 (Cp = η5-C5H5, Cp∗ = η5-C5Me5)

    KAUST Repository

    Laws, Derek R.

    2014-09-22

    The one-electron oxidations of two dimers of half-sandwich osmium carbonyl complexes have been examined by electrochemistry, spectro-electrochemistry, and computational methods. The all-terminal carbonyl complex Os2Cp2(CO)4 (1, Cp = η5-C5H5) undergoes a reversible one-electron anodic reaction at E1/2 = 0.41 V vs ferrocene in CH2Cl2/0.05 M [NBu4][B(C6F5)4], giving a rare example of a metal-metal bonded radical cation unsupported by bridging ligands. The IR spectrum of 1+ is consistent with an approximately 1:1 mixture of anti and gauche structures for the 33 e- radical cation in which it has retained all-terminal bonding of the CO ligands. Density functional theory (DFT) calculations, including orbital-occupancy-perturbed Mayer bond-order analyses, show that the highest-occupied molecular orbitals (HOMOs) of anti-1 and gauche-1 are metal-ligand delocalized. Removal of an electron from 1 has very little effect on the Os-Os bond order, accounting for the resistance of 1+ to heterolytic cleavage. The Os-Os bond distance is calculated to decrease by 0.10 å and 0.06 å as a consequence of one-electron oxidation of anti-1 and gauche-1, respectively. The CO-bridged complex Os2Cp∗2(μ-CO)2(CO)2 (Cp∗ = η5-C5Me5), trans-2, undergoes a more facile oxidation, E1/2 = -0.11 V, giving a persistent radical cation shown by solution IR analysis to preserve its bridged-carbonyl structure. However, ESR analysis of frozen solutions of 2+ is interpreted in terms of the presence of two isomers, most likely anti-2+ and trans-2+, at low temperature. Calculations show that the HOMO of trans-2 is highly delocalized over the metal-ligand framework, with the bridging carbonyls accounting for about half of the orbital makeup. The Os-Os bond order again changes very little with removal of an electron, and the Os-Os bond length actually undergoes minor shortening. Calculations suggest that the second isomer of 2+ has the anti all-terminal CO structure. (Figure Presented) © 2014 American

  17. Preliminary data from {gamma}-cardiography during the abatement of an asthmatic attack (1961); Premieres donnees de la {gamma}-cardiographie au decours de l'etat de mal asthmatique (1961)

    Energy Technology Data Exchange (ETDEWEB)

    Georges, R; Vernejoul, P de; Raynaud, C; Blanchon, P; Kellershohn, C; Turiaf, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1961-07-01

    The authors used gamma cardiology during the abatement of 16 cases of asthma with a view to detecting heart attacks not otherwise visible with routine methods of examination: clinical, radiological and electro-cardio-graphical. In gamma cardiology, a radioactive indicator is used and its path followed in the cavities of the heart. The method makes it possible to study the circulation in the right heart, the pulmonary crossing, and the left heart, as well as evaluation of the heart-flow. As a result of their investigations the authors, after having discussed the significance of the data obtained with the method, suggest that it is possible by the use of gamma cardiography during the abatement of an asthma attack: 1- To confirm attacks of the right heart which have already been detected by ordinary methods. 2- To confirm the presence of modifications in the recorded curves which suggest, in the case of the left heart, possible attack; such on attack is also indicated, in a small number of cases, by electrocardiography curves. Some considerations are put forward by the authors concerning the physiopathology of attacks on the left heart. (authors) [French] Les auteurs ont fait appel a la gammacardiographie au decours de 16 cas d'etat de mal asthmatique, dans le but d'objectiver des atteintes cardiaques incapables d'etre revelees par les moyens d'exploration de routine: cliniques, radiologiques et electrocardiographiques. La gammacardiographie est un procede qui enregistre a l'aide d'un indicateur radioactif, le trajet de celui-ci dans les cavites cardiaques. Elle permet l'etude de la circulation dans le coeur droit, de la traversee pulmonaire, et le coeur gauche, de meme que le calcul du debit cardiaque. Au terme de leurs investigations, les auteurs apres avoir discute la signification des donnees fournies par la methode admettent que la gammacardiographie objective au secours de l'etat de mal asthmatique: 1- La confirmation de l'atteinte du coeur droit deja etablie

  18. Cancer du rein et Grossesse: A propos d’une nouvelle observation

    Directory of Open Access Journals (Sweden)

    A. Majdoub

    2017-12-01

    Nous rapportons le cas d’une patiente âgée de 38 ans, sans antécédents pathologiques notables, enceinte avec un terme de 16 semaines d’aménorrhée, présentant des lombalgies gauches. Le diagnostic de tumeur rénale était retenu sur les données du couple échographie rénale et IRM abdominale. La patiente a bénéficié d’une néphrectomie élargie par voie lombaire. L’analyse histologique de la pièce de néphrectomie totale a révélé un adénocarcinome à cellules claires. L’évolution était favorable après le traitement avec une grossesse menée à terme.

  19. Clustering mechanism of ethanol-water mixtures investigated with photothermal microfluidic cantilever deflection spectroscopy

    Science.gov (United States)

    Ghoraishi, M. S.; Hawk, J. E.; Phani, Arindam; Khan, M. F.; Thundat, T.

    2016-04-01

    The infrared-active (IR) vibrational mode of ethanol (EtOH) associated with the asymmetrical stretching of the C-C-O bond in pico-liter volumes of EtOH-water binary mixtures is calorimetrically measured using photothermal microfluidic cantilever deflection spectroscopy (PMCDS). IR absorption by the confined liquid results in wavelength dependent cantilever deflections, thus providing a complementary response to IR absorption revealing a complex dipole moment dependence on mixture concentration. Solvent-induced blue shifts of the C-C-O asymmetric vibrational stretch for both anti and gauche conformers of EtOH were precisely monitored for EtOH concentrations ranging from 20-100% w/w. Variations in IR absorption peak maxima show an inverse dependence on induced EtOH dipole moment (μ) and is attributed to the complex clustering mechanism of EtOH-water mixtures.

  20. Competing hydrogen bonding in methoxyphenols: The rotational spectrum of o-vanillin

    Science.gov (United States)

    Cocinero, Emilio J.; Lesarri, Alberto; Écija, Patricia; Basterretxea, Francisco; Fernández, José A.; Castaño, Fernando

    2011-05-01

    The conformational preferences of o-vanillin have been investigated in a supersonic jet expansion using Fourier transform microwave (FT-MW) spectroscopy. Three molecular conformations were derived from the rotational spectrum. The two most stable structures are characterized by a moderate O sbnd H···O dbnd C hydrogen bond between the aldehyde and the hydroxyl groups, with the methoxy side chain either in plane (global minimum a- cis-trans) or out of plane (a- cis-gauche) with respect to the aromatic ring. In the third conformer the aldehyde group is rotated by ca. 180°, forming a O sbnd H···O hydrogen bond between the methoxy and hydroxyl groups (s- trans-trans). Rotational parameters and relative populations are provided for the three conformations, which are compared with the results of ab initio (MP2) and density-functional (B3LYP, M05-2X) theoretical predictions.

  1. The Conformational Behaviour of Glucosamine

    Science.gov (United States)

    Peña, Isabel; Kolesniková, Lucie; Cabezas, Carlos; Bermúdez, Celina; Berdakin, Matías; Simao, Alcides; Alonso, José L.

    2014-06-01

    A laser ablation method has been successfully used to vaporize the bioactive amino monosaccharide D-glucosamine. Three cyclic α-4C1 pyranose forms have been identified using a combination of CP-FTMW and LA-MB-FTMW spectroscopy. Stereoelectronic hyperconjugative factors, like those associated with anomeric or gauche effects, as well as the cooperative OH\\cdotsO, OH\\cdotsN and NH\\cdotsO chains, extended along the entire molecule, are the main factors driving the conformational behavior. All observed conformers exhibit a counter-clockwise arrangement (cc) of the network of intramolecular hydrogen bonds. The results are compared with those recently obtained for D-glucose. J. L. Alonso, M. A. Lozoya, I. Peña, J. C. López, C. Cabezas, S. Mata, S. Blanco, Chem. Sci. 2014, 5, 515.

  2. “Just an American Boy”. The Political Songwriting of Steve Earle “Just an American Boy” : la chanson politique de Steve Earle

    Directory of Open Access Journals (Sweden)

    Richard Jobes

    2009-11-01

    Full Text Available Un an après les attentats du 11 septembre, Steve Earle, dans son album Jerusalem, a été le premier à faire entendre dans le monde du rock une voix discordante sur l’Amérique contemporaine. Honni par la droite, qui s’est inscrite en faux contre une prise de position qu’elle considère antipatriotique, mais salué par la gauche américaine, Jerusalem s’est retrouvé au centre du débat politique actuel. L’objet de cet article sera de montrer comment s’inscrit ce disque dans le contexte des États-Unis d’aujourd’hui ainsi que sa place dans l’œuvre engagée de Steve Earle.

  3. Raman study of vibrational dynamics of aminopropylsilanetriol in gas phase

    Science.gov (United States)

    Volovšek, V.; Dananić, V.; Bistričić, L.; Movre Šapić, I.; Furić, K.

    2014-01-01

    Raman spectrum of aminopropylsilanetriol (APST) in gas phase has been recorded at room temperature in macro chamber utilizing two-mirror technique over the sample tube. Unlike predominantly trans molecular conformation in condensed phase, the spectra of vapor show that the molecules are solely in gauche conformation with intramolecular hydrogen bond N⋯Hsbnd O which reduces the molecular energy in respect to trans conformation by 0.152 eV. The assignment of the molecular spectra based on the DFT calculation is presented. The strong vibrational bands at 354 cm-1, 588 cm-1 and 3022 cm-1 are proposed for verifying the existence of the ring like, hydrogen bonded structure. Special attention was devoted to the high frequency region, where hydrogen bond vibrations are coupled to stretchings of amino and silanol groups.

  4. Tetrabromido[4-(triphenylphosphanyloxybutyl]tellurium acetonitrile monosolvate

    Directory of Open Access Journals (Sweden)

    Sari M. Närhi

    2013-02-01

    Full Text Available In the title compound, [TeBr4(C22H23OP]·CH3CN, the Te atom exhibits a square-pyramidal coordination with an apical Te—C bond and four basal Te—Br bonds. The conformation of the aliphatic C—C—C—C chain is gauche [torsion angle = −67.7 (8°]. A weak C—H...Br interaction helps to establish the conformation. In the crystal, there is a weak secondary bonding interaction [Te...N = 3.456 (11 Å] between the Te atom and the N atom of the solvent molecule, which completes a distorted TeNCBr4 octahedron. Inversion dimers linked by pairs of C—H...Br interactions are also observed.

  5. Investigation of a van der Waals complex with C 1 symmetry: the free-jet rotational spectrum of 1,2-difluoroethane-Ar

    Science.gov (United States)

    Melandri, Sonia; Velino, Biagio; Favero, Paolo G.; Dell'Erba, Adele; Caminati, Walther

    2000-04-01

    The van der Waals complex between Ar and 1,2-difluoroethane has been investigated by free-jet absorption millimeter-wave spectroscopy in the frequency range 60-78 GHz. The analysis of the spectroscopic constants derived from the rotational spectrum allowed the determination of the dimer's structure. 1,2-Difluoroethane is in the gauche conformation and the Ar atom is in a position stabilized by the interaction with one fluorine and the two carbon atoms. The distance between Ar and the center of mass (CM) of the monomer is 3.968 Å, the angle between the Ar-CM line and the C-C bond is 65° and the dihedral angle Ar-CM-C-C is 99°. From centrifugal distortion effects the dissociation energy of the complex has been estimated to be 2.1 kJ/mol.

  6. SPECTROSCOPIC CHARACTERIZATION AND DETECTION OF ETHYL MERCAPTAN IN ORION

    International Nuclear Information System (INIS)

    Kolesniková, L.; Alonso, J. L.; Daly, A. M.; Tercero, B.; Cernicharo, J.; Gordon, B. P.; Shipman, S. T.

    2014-01-01

    New laboratory data of ethyl mercaptan, CH 3 CH 2 SH, in the millimeter- and submillimeter-wave domains (up to 880 GHz) provided very precise values of the spectroscopic constants that allowed the detection of gauche-CH 3 CH 2 SH toward Orion KL. This identification is supported by 77 unblended or slightly blended lines plus no missing transitions in the range 80-280 GHz. A detection of methyl mercaptan, CH 3 SH, in the spectral survey of Orion KL is reported as well. Our column density results indicate that methyl mercaptan is ≅ 5 times more abundant than ethyl mercaptan in the hot core of Orion KL

  7. George Sand et la République (entretien avec Michelle Perrot

    Directory of Open Access Journals (Sweden)

    Jean-Claude Vimont

    2012-06-01

    Full Text Available TRAMES : Vous présentez les figures passées de l’engagement politique, dans un numéro spécial de Vingtième siècle (n° 60, sous le titre « La cause du peuple » , éphémère journal de George Sand en avril 1848 et organe maoïste de la Gauche Prolétarienne après mai 1968. Est-ce pour fixer un point de départ, les années 1840, à la généalogie des engagements d’écrivains, d’intellectuels auprès d’un peuple qui est en passe de devenir prolétariat industriel, classe ouvrière ? Y a-t-il une filiation ...

  8. Anthologie de la photographie africaine et de l’océan Indien

    OpenAIRE

    Menut, Nicolas

    2007-01-01

    Un cliché noir et blanc de petit format, un daguerréotype jauni sur lequel les contours du visage ont quasiment disparu. En haut à gauche, une série de chiffres difficilement lisibles : 1… 8… 4… De quelle date s’agit-il ? 1840 ? 1845 ? 1849 ? À défaut de trancher, le regard se pose à nouveau sur le visage situé au centre de la photographie. L’homme semble entre deux âges, sa peau est sombre, on devine une veste, une cravate. Ses yeux délavés fixent l’obturateur, le port de tête est droit, sér...

  9. Polarized Raman and Infrared Spectroscopy and ab Initio Calculation of Palmitic and Stearic Acids in the Bm and C Forms.

    Science.gov (United States)

    L da Silva, L F; Andrade-Filho, T; Freire, P T C; Filho, J Mendes; da Silva Filho, J G; Saraiva, G D; Moreira, S G C; de Sousa, F F

    2017-06-29

    A complete experimental study on the vibrational properties of palmitic and stearic acids crystallized in the B m and C forms, both belonging to the monoclinic system with the P2 1 /a (C 2h 5 ) space group, through polarized Raman and infrared spectroscopy, is reported in this paper. Density functional theory calculations were also performed to assign the normal modes and to help in the interpretation of the experimental data. The different polarizations were compared and their influence on the spectral profiles, in both the lattice and the internal mode regions, was discussed. In general, the Raman and infrared spectra exhibit accentuated differences among the polymorphic forms, which are associated with the different molecular modifications, defined as gauche and all-trans conformations. Insights about interaction among different groups are also furnished.

  10. Tris[2-(2H-indazol-2-ylethyl]amine

    Directory of Open Access Journals (Sweden)

    Saúl Ovalle

    2012-06-01

    Full Text Available The title tertiary amine, C27H27N7, a potential tripodal ligand for coordination chemistry, crystallizes with the central N atom located on a threefold axis of a trigonal cell. The gauche conformation of the N(amime—CH2—CH2—N(indazole chain [torsion angle = −64.2 (2°] places the pendant 2H-indazole heterocycles surrounding the symmetry axis, affording a claw-like shaped molecule. Two symmetry-related indazole planes in the molecule make an acute angle of 60.39 (4°. The lone pair of the tertiary N atom is located inside the cavity, and should thus be inactive (as a ligand. In the crystal, neither significant π–π nor C—H...π interactions between molecules are found.

  11. Identifying stereoisomers by ab-initio calculation of secondary isotope shifts on NMR chemical shieldings.

    Science.gov (United States)

    Böhm, Karl-Heinz; Banert, Klaus; Auer, Alexander A

    2014-04-23

    We present ab-initio calculations of secondary isotope effects on NMR chemical shieldings. The change of the NMR chemical shift of a certain nucleus that is observed if another nucleus is replaced by a different isotope can be calculated by computing vibrational corrections on the NMR parameters using electronic structure methods. We demonstrate that the accuracy of the computational results is sufficient to even distinguish different conformers. For this purpose, benchmark calculations for fluoro(2-2H)ethane in gauche and antiperiplanar conformation are carried out at the HF, MP2 and CCSD(T) level of theory using basis sets ranging from double- to quadruple-zeta quality. The methodology is applied to the secondary isotope shifts for 2-fluoronorbornane in order to resolve an ambiguity in the literature on the assignment of endo- and exo-2-fluoronorbornanes with deuterium substituents in endo-3 and exo-3 positions, also yielding insight into mechanistic details of the corresponding synthesis.

  12. Structure of deformable diatomic molecules: a modified n-butane liquid

    International Nuclear Information System (INIS)

    Jang, Seanea; Kim, Soonchul; Lee, Songhi

    2005-01-01

    The density functional approximation for polyatomic molecules, which is based on the bridge function of the intermolecular interaction, was developed and applied to investigate the thermodynamic and the structural properties of deformable diatomic molecules. The Percus trick was employed to calculate the uniform structure of modified n-butane. The calculated static correlation functions were used to predict the density behaviors of a modified n-butane liquid at liquid-solid interfaces. The theoretical results show that (i) at low densities, the hypernetted-chain (HNC) equation compares with the density functional approximation based on the bridge function and that (ii) the relative population between the gauche and the trans states strongly affects the liquid structure at liquid-solid interfaces.

  13. Conjugaison progressive du français avec 400 exercices

    CERN Document Server

    Boularès, Michèle

    1999-01-01

    La Conjugaison progressive du français s'adresse aux grands adolescents et aux adultes de tous niveaux. C'est un ouvrage d'apprentissage des formes verbales. On trouve sur la page de gauche : - la règle de formation de chaque temps ; - les verbes types présentés en tableaux et accompagnés d'une liste de verbes conjugués sur le même modèle ; - des remarques phonétiques ou orthographiques ; - des explications sur les difficultés particulières. La page de droite propose des exercices et des activités de difficulté progressive. C'est également un ouvrage de référence grâce aux nombreux tableaux de conjugaison qu'il contient.

  14. Identifying Stereoisomers by ab-initio Calculation of Secondary Isotope Shifts on NMR Chemical Shieldings

    Directory of Open Access Journals (Sweden)

    Karl-Heinz Böhm

    2014-04-01

    Full Text Available We present ab-initio calculations of secondary isotope effects on NMR chemical shieldings. The change of the NMR chemical shift of a certain nucleus that is observed if another nucleus is replaced by a different isotope can be calculated by computing vibrational corrections on the NMR parameters using electronic structure methods. We demonstrate that the accuracy of the computational results is sufficient to even distinguish different conformers. For this purpose, benchmark calculations for fluoro(2-2Hethane in gauche and antiperiplanar conformation are carried out at the HF, MP2 and CCSD(T level of theory using basis sets ranging from double- to quadruple-zeta quality. The methodology is applied to the secondary isotope shifts for 2-fluoronorbornane in order to resolve an ambiguity in the literature on the assignment of endo- and exo-2-fluoronorbornanes with deuterium substituents in endo-3 and exo-3 positions, also yielding insight into mechanistic details of the corresponding synthesis.

  15. Vichy – Lit de l’Allier

    OpenAIRE

    Troubat, Olivier

    2014-01-01

    Code INSEE de la commune : 03310 Lien Atlas (MCC) : http://atlas.patrimoines.culture.fr/atlas/trunk/index.php?ap_theme=DOM_2.01.02&ap_bbox=3.405;46.111;3.446;46.153 Datation d’un moulin pendu gallo-romain sur culée de pont à Vichy dans le lit de l’Allier et relevés complémentaires Pont gallo-romain En 2007, un pont gallo-romain avait été relevé dans le lit de l’Allier à Vichy et Bellerive. L’un des pieux, rive gauche, avait été daté au carbone 14 entre 0 et 180 apr. J.-C. (rapport 2007). Nous...

  16. Apport de l’histopathologie dans le diagnostic d’une calcinose scrotale: a propos d’un cas

    Directory of Open Access Journals (Sweden)

    K. Doh

    2015-03-01

    Full Text Available La calcinose scrotale est une maladie rare, bénigne, de pathogénie incertaine caractérisée par de nombreux nodules indolores, durs du scrotum en absence de tout trouble métabolique systémique. Nous rapportons le cas d’un patient âgé de 57 ans qui présente une calcinose scrotale de découverte histologique fortuite associée à un eczéma chronique et une hernie inguinale gauche. Nous discutons après une revue de la littérature, les aspects pathogéniques, cliniques, thérapeutiques et anatomopathologiques de cette pathologie mal comprise.

  17. 4-Chloro-N-(3,4-dichlorophenyl-2-methylbenzenesulfonamide

    Directory of Open Access Journals (Sweden)

    Vinola Z. Rodrigues

    2011-11-01

    Full Text Available In the title compound, C13H10Cl3NO2S, the N—C bond in the C—SO2—NH—C segment forms trans and gauche torsion angles with respect to the S=O bonds. Further, the N—H bond in the C—SO2—NH—C segment is anti to the meta-Cl atom in the anilino benzene ring and nearly syn with respect to the ortho-methyl group in the sulfonyl benzene ring. The C—SO2—NH—C torsion angle is −49.4 (2°. The sulfonyl and aniline benzene rings are tilted relative to each other by 54.6 (1°. In the crystal, molecules are linked into chains along the c-axis direction by intermolecular N—H...O hydrogen bonds.

  18. 2-Methyl-N-(4-methylbenzoylbenzenesulfonamide

    Directory of Open Access Journals (Sweden)

    B. Thimme Gowda

    2010-04-01

    Full Text Available The asymmetric unit of the title compound, C15H15NO3S, contains two independent molecules. The conformations of the N—C bonds in the C—SO2—NH—C(O segments have gauche torsions with respect to the SO bonds. Further, the molecules are twisted at the S atoms with torsion angles of −53.1 (2 and 61.2 (2° in the two molecules. The dihedral angles between the sulfonyl benzene rings and the —SO2—NH—C—O segments are 86.0 (1 and 87.9 (1°. Furthermore, the dihedral angles between the sulfonyl and the benzoyl benzene rings are 88.1 (1 and 83.5 (1° in the two molecules. In the crystal, molecules are linked by N—H...O(S hydrogen bonds.

  19. 4-Chloro-N-(3,4-dimethylphenyl-2-methylbenzenesulfonamide

    Directory of Open Access Journals (Sweden)

    Vinola Z. Rodrigues

    2011-11-01

    Full Text Available In the title compound, C15H16ClNO2S, the conformation of the N—C bond in the C—SO2—NH—C segment is gauche with respect to the S=O bonds. Further, the N—H bond in the C—SO2—NH—C segment is syn with respect to the meta-methyl group in the aniline benzene ring and the ortho-methyl group in the sulfonyl benzene ring. The C—SO2—NH—C torsion angle is −49.72 (18°. The sulfonyl and aniline benzene rings are tilted relative to each other by 71.6 (1°. The crystal structure features inversion-related dimers linked by pairs of N—H...O hydrogen bonds.

  20. Un autoportrait de Berthe Morisot

    OpenAIRE

    Bonnet, Marie-Jo

    2006-01-01

    À voir la détermination avec laquelle Berthe Morisot nous regarde, nous pourrions penser qu’elle a trouvé facilement sa place d’artiste. Une palette est esquissée sur la gauche de trois mouvements tournants. Elle porte une fleur bleue à la boutonnière, «  comme une décoration  », dira Mallarmé, elle se tient droite, la tête tournée vers le spectateur, et elle nous regarde de ses célèbres yeux noirs qui ont tant fasciné Manet. Paul Valéry écrira d’ailleurs au sujet de ses yeux  : «  Berthe Mor...

  1. Structural analysis of syndiotactic polystyrene

    Energy Technology Data Exchange (ETDEWEB)

    Mitani, Masahiro

    1988-09-01

    Since the stereostructure of a high-molecular compound includes three types of isotactic, atactic and sydiotactic structures, a high-molecular compound with excellent properties can be produced by controlling the stereogularity of the compound with the identical composition. The stereoregularity of a stereogular polystyrene, or syndiotactic polystyrene (SPS), which had been successfully synthesized recently was quantitatively determined and the open chain structure by polymerization was investigated by nuclear magnetic resonance spectroscopy. Two SPSs were synthesized from cis-beta-d/sub/1-styrene and trans-beta-d/sub/1-styrene with alpha, beta, beta-d/sub/3-styrene. The results of spectral analysis of these two SPSs indicate that the former is of trans-conformation and the latter is of gauche conformation and that accordingly the open chain structure by polymerization of SPS is of cis-open chain and SPS has a planar zigzag structure even in the solution. (5 figs, 9 refs)

  2. Effect of electron irradiation on poly(vinylidene fluoride-trifluoroethylene) 56/44 mol% copolymers

    International Nuclear Information System (INIS)

    Guo, S S; Zhao, X-Z; Lu, S G; Lau, S T; Chan, H L W

    2004-01-01

    High-energy electron-irradiated poly(vinylidene fluoride-trifluoroethylene) 56/44 mol% copolymers are studied in a broad dose ranging from 0 to 110 Mrad. The experimental results are obtained by differential scanning calorimetry (DSC), x-ray diffraction, dielectric constant, dc conductivity and polarization hysteresis loop based on structural changes and dielectric relaxation behaviour. All the x-ray and DSC results show that both the crystalline and polar ordering decreased after irradiation, indicating a partial recovery from trans-gauche bonds to local trans bonds (polar ordering). The dielectric relaxation peaks, obeying the Vogel-Fulcher Law, indicate that the copolymers have transformed from a normal ferroelectric to a relaxor ferroelectric. It is also found that dc conductivity can be modulated with electron irradiation, as well as the hysteresis loop characteristics

  3. Dynamics of liquids, molecules, and proteins measured with ultrafast 2D IR vibrational echo chemical exchange spectroscopy.

    Science.gov (United States)

    Fayer, M D

    2009-01-01

    A wide variety of molecular systems undergo fast structural changes under thermal equilibrium conditions. Such transformations are involved in a vast array of chemical problems. Experimentally measuring equilibrium dynamics is a challenging problem that is at the forefront of chemical research. This review describes ultrafast 2D IR vibrational echo chemical exchange experiments and applies them to several types of molecular systems. The formation and dissociation of organic solute-solvent complexes are directly observed. The dissociation times of 13 complexes, ranging from 4 ps to 140 ps, are shown to obey a relationship that depends on the complex's formation enthalpy. The rate of rotational gauche-trans isomerization around a carbon-carbon single bond is determined for a substituted ethane at room temperature in a low viscosity solvent. The results are used to obtain an approximate isomerization rate for ethane. Finally, the time dependence of a well-defined single structural transformation of a protein is measured.

  4. Château-Thierry – La Blanchisserie

    OpenAIRE

    Baillieu, Michel

    2013-01-01

    Identifiant de l'opération archéologique : 9254 Date de l'opération : 2007 (EX) Le diagnostic archéologique portait sur une surface assez importante (5 627 m²) pour un aménagement en contexte urbain. Ce projet de construction de deux immeubles de logements initié par la société Logivam SA d’HLM est situé au sud de la rivière de la Marne, juste en bordure de la rive gauche du canal dit de la Fausse Marne. Ce secteur de la ville, peu reconnu archéologiquement jusqu’alors, se trouve en dehors de...

  5. La Confédération paysanne et José Bové, des actions médiatiques au service d'un projet ?

    OpenAIRE

    Martin, Jean-Philippe

    2005-01-01

    Ce travail veut replacer l'action menée à Millau, pendant l'été 1999, par des éleveurs de brebis et José Bové, contre un Mac Donald's dans l'histoire du syndicat auquel il se réfère, la Confédération paysanne. Ce syndicat est né en 1987 du rapprochement de courants de gauche. Il entend défendre en priorité les petits et moyens producteurs, promouvoir une agriculture qui produisent des aliments de qualité et ne pollue pas. Dans son projet, la valeur de solidarité est primordiale. Cette ...

  6. 4-(3-Bromopropyloxy-1-hydroxy-9,10-anthraquinone

    Directory of Open Access Journals (Sweden)

    Natsumi Ohira

    2016-05-01

    Full Text Available In the molecule of the title compound, C17H13BrO4, the anthraquinone ring system is slightly bent, with a dihedral angle of 169.99 (7° between the planes of the two benzene rings. The side chain (O—C—C—C—Br has a gauche–gauche conformation, as indicated by the O—C—C—C and C—C—C—Br torsion angles of −66.9 (2 and −65.8 (2°, respectively. In addition, there is an intramolecular O—H...O hydrogen bond enclosing an S(6 ring motif. The hydrogen-bond donor is bifurcated; in the crystal, a pair of O—H...O hydrogen bonds connects two molecules, forming an inversion dimer with an R22(12 ring motif.

  7. Influence of the form of the magnetic axis on the regions of stability and their variations (1963); Influence de la forme de l'axe magnetique sur les plages de stabilite et leur variation (1963)

    Energy Technology Data Exchange (ETDEWEB)

    Mercier, C; Tasso, H [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1963-07-01

    We study many cases of plane and twisted magnetic axis and we show for a set of regular magnetic axis tending to racetrack limit, the stability regions tend rapidly to the racetrack stability. But, for the case at two axis apparently not very far, we find that the corresponding regions of stability may be sometimes sensibly different. (authors) [French] Nous etudions plusieurs exemples d'axes magnetiques plans et gauches et montrons que pour une suite d'axes magnetiques qui converge vers une limite du type hippodrome, les plages de stabilite convergent rapidement vers la plage limite. Mais, si on prend deux axes apparemment peu eloignes, on trouve que les plages correspondantes peuvent etre parfois sensiblement differentes. (auteurs)

  8. ALICE presents its first award to Industry

    CERN Multimedia

    Maximilien Brice

    2003-01-01

    Behind from left to right (Derrière de gauche à droite): Bernardo Mota, member of the ALTRO design team, Jurgen Schukraft, ALICE Spokesperson, Luciano Musa, leader of the ALTRO Design Team and Coordinator of the ALICE TPC FEE, Roberto Camapagnolo, member of the ALICE TPC FEE team, Jean-Pierre Coffin, Deputy of the ALICE Collaboration Board Chairman, Hans de Groot ALICE Resource Coordinator, Laurent Degoujon, ST - Data Converter Design Manager, Claude Engster, member of the ALICE TPC FEE team, Alain Delpi, ST - Data Converter Business Unit Manager, Carmen Gonzalez, member of the ALICE TPC FEE team, Yiota Foka, ALICE Outreach Coordinator; Front: Fabio Formenti , EP-ED Group Leader, Juan Antonio Rubio, ETT Division Leader.

  9. Editorial 15 mai 1997

    Directory of Open Access Journals (Sweden)

    Denise Pumain

    1997-05-01

    Full Text Available Cybergeo se dote d'un éditorial pour signaler aux lecteurs les nouveautés du mois. D'abord, un nom enfin plus simple pour accéder au site: tapez désormais: www.cybergeo.presse.fr Sans doute avez-vous déjà repéré nos nouveaux services, sinon, regardez dans la colonne de gauche! Nous aimerions en outre insérer dans nos rubriques des résumés, en anglais, des thèses soutenues récemment. Les résumés en français sont déjà publiés dans la Lettre d'Intergéo, Cybergeo nous paraît l'endroit idéal pour...

  10. Spectroscopic identification of ethanol-water conformers by large-amplitude hydrogen bond librational modes

    DEFF Research Database (Denmark)

    Andersen, Jonas; Heimdal, J.; Larsen, René Wugt

    2015-01-01

    ⋯HO hydrogen bond acceptor in the two most stable conformations. In the most stable conformation, the water subunit forces the ethanol molecule into its less stable gauche configuration upon dimerization owing to a cooperative secondary weak O⋯HC hydrogen bondinteraction evidenced by a significantly blue......-shift of the low-frequency in-plane donor OH librational band origin. The strong correlation between the low-frequency in-plane donor OH librational motion and the secondary intermolecular O⋯HC hydrogen bond is demonstrated by electronic structure calculations. The experimental findings are further supported...... by CCSD(T)-F12/aug-cc-pVQZ calculations of the conformationalenergy differences together with second-order vibrational perturbation theory calculations of the large-amplitude donor OH librational band origins....

  11. HYPOTHÈSES SUR L'ORIGINE DES BRUITS DU CŒUR ET DES ACCIDENTS DE DÉCOMPRESSION EN PLONGÉE : LA CAVITATION. HYPOTHÈSE SUR L'ORIGINE DE LA FERMETURE DES VALVES CARDIAQUES : LE PHÉNOMÈNE DE VENTOUSE.

    OpenAIRE

    Venet , Richard ,; Pavie , Alain; Leger , Philippe

    2012-01-01

    Nous avons proposé, dans un travail antérieur, l'hypothèse d'un phénomène de cavitation à l'origine des bruits de Korotkoff. Encouragés par l'aphorisme de MacDonald comme quoi le phénomène de cavitation est plus fréquent qu'on peut le penser dans le système cardio-vasculaire, nous avons appliqué la théorie de Womersley aux enregistrements hémodynamiques exposés dans la littérature médicale. L'enregistrement simultané des pressions du ventricule gauche (PVG), de l'aorte (PAo) et de l'oreillett...

  12. HYPOTHÈSES SUR L'ORIGINE DES BRUITS DU CŒUR ET DES ACCIDENTS DE DÉCOMPRESSION EN PLONGÉE : LA CAVITATION. HYPOTHÈSE SUR L'ORIGINE DE LA FERMETURE DES VALVES CARDIAQUES : LE RETARD A LA FERMETURE DES VALVES (COUP DE CLAPET) ET LE PHÉNOMÈNE DE VENTOUSE.

    OpenAIRE

    Venet , Richard ,

    2012-01-01

    Nous avons proposé, dans un travail antérieur, l'hypothèse d'un phénomène de cavitation à l'origine des bruits de Korotkoff. Encouragés par l'aphorisme de MacDonald comme quoi le phénomène de cavitation est plus fréquent qu'on peut le penser dans le système cardio-vasculaire, nous avons appliqué la théorie de Womersley aux enregistrements hémodynamiques exposés dans la littérature médicale. L'enregistrement simultané des pressions du ventricule gauche (PVG), de l'aorte (PAo) et de l'oreillett...

  13. HYPOTHÈSES SUR L'ORIGINE DES BRUITS DU COEUR ET DES ACCIDENTS DE DÉCOMPRESSION EN PLONGÉE : LA CAVITATION

    OpenAIRE

    Venet , Richard

    2007-01-01

    Nous avons proposé, dans un travail antérieur, l'hypothèse d'un phénomène de cavitation à l'origine des bruits de Korotkoff. Encouragés par l'aphorisme de MacDonald comme quoi le phénomène de cavitation est plus fréquent qu'on peut le penser dans le système cardio-vasculaire, nous avons appliqué la théorie de Womersley aux enregistrements hémodynamiques exposés dans la littérature médicale. L'enregistrement simultané des pressions du ventricule gauche (PVG), de l'aorte (PAo) et de l'oreillett...

  14. Combined effect of solvents and gamma irradiation on the infrared absorption spectra of polyethylene terephthalate

    International Nuclear Information System (INIS)

    Rabie, S.M.; ElBially, A.; Elshourbaguie, S.

    1991-01-01

    The combined effect of solvents and gamma irradiation on the intensities of infrared absorption bands of polyethylene terephthalate, particularly the bands sensitive to conformational changes, were studied. The results revealed that solvent treatment of PET results in significant changes in the intensities of its infrared absorption bands and the exposure of PET to gamma radiation in the presence of solvents helps in the appearance of the two bands at 1550 and 1630 cm . Also, the combined effect of solvents and gamma irradiation on the intensities of the absorption bands is greater than the effect of each agent alone. The extent of the induced changes depends on the nature of solvent and the applied dosage. Further more, for any given solvent or dosage, the rate of change of the intensities of the trans band is not equal to that of the gauche bands.3 fig

  15. Modificação química de poli(tereftalato de etileno pós-consumo por reação com ácido sulfúrico: estrutura e propriedades Chemical modification of post consumer poly(ethylene terephthalate by sulfuric acid reaction: structure and properties

    Directory of Open Access Journals (Sweden)

    Janaína G. Alonso

    2005-03-01

    Full Text Available PET pós-consumo foi modificado quimicamente através de reação com ácido sulfúrico por diferentes tempos. O material modificado foi caracterizado por DSC e FTIR-PAS e XPS. Verificou-se que a intensidade relativa do isômero trans diminui enquanto do isômero gauche aumenta para tempos de reação entre 0 e 60 minutos. Após 60 minutos de reação observou-se a presença de endotermas múltiplas que podem ser relacionadas com o desenvolvimento de estruturas intermediárias porque as intensidades relativas dos isômeros trans e gauche não apresentam variação significativa. O valor determinado de capacidade de troca iônica do PET pós-consumo modificado (PETS-pc é comparável com os valores de resinas ácidas comerciais e não é afetado no intervalo de tempo de reação utilizado. Os valores da capacidade máxima de adsorção, qm, e do parâmetro de afinidade entre o adsorvente e o adsorvato, K, (111,18 ppm e 531,91 mg de corante/100g de adsorvente, respectivamente para a adsorção do corante Remazol vermelho na amostra quimicamente modificada por 30 minutos foram calculados a partir da isoterma de adsorção de Langmuir. Os resultados indicam que esse material possui características adsorventes, podendo vir a ser utilizado para tratamento de efluente de indústria de tingimento têxtil.Chemical modification of post consumer PET was carried out by reaction with sulfuric acid. The modified material was characterized by DSC, XPS and FTIR-PAS measurements. The relative intensity of trans isomer increases while it decreases for gauche isomer for reaction times from 0 up to 60 min. After 60 minutes of reaction multiple endotherms were observed, which may be related to the development of an intermediated structure, since the relative intensities of the trans and gauche isomers do not change. The ionic exchange capacity of the modified post consumer poly(ethylene terephthalate, PETS-pc, is comparable to commercial acid resins and is not

  16. Perry Anderson, Spectrum. From Right to Left in the World of Ideas, Londres-New York, Verso, 2005.

    Directory of Open Access Journals (Sweden)

    Gabriele Pedullà

    2010-09-01

    Full Text Available Perry Anderson se charge d’expliciter lui-même le sens de son dernier recueil d’essais, Spectrum : « On peut le considérer comme une sorte de travelling qui, se déplaçant de droite à gauche, éclaircit un paysage intellectuel particulier. […] Voilà le spectre auquel fait allusion le titre. » Il y a toutefois de bonnes raisons de proposer une autre lecture. Étant donné que le grand thème unificateur de ces essais, parus à l’origine entre 1992 et 2005 en différents lieux, est le monde des idées ...

  17. SPECTROSCOPIC CHARACTERIZATION AND DETECTION OF ETHYL MERCAPTAN IN ORION

    Energy Technology Data Exchange (ETDEWEB)

    Kolesniková, L.; Alonso, J. L.; Daly, A. M. [Grupo de Espectroscopía Molecular (GEM), Edificio Quifima, Laboratorios de Espectroscopía y Bioespectroscopía, Parque Científico UVa, Unidad Asociada CSIC, Universidad de Valladolid, E-47011 Valladolid (Spain); Tercero, B.; Cernicharo, J. [Departamento de Astrofísica, Centro de Astrobiología CAB, CSIC-INTA, Ctra. de Torrejón a Ajalvir km 4, E-28850 Madrid (Spain); Gordon, B. P.; Shipman, S. T., E-mail: lucie.kolesnikova@uva.es, E-mail: jlalonso@qf.uva.es, E-mail: adammichael.daly@uva.es, E-mail: terceromb@cab.inta-csic.es, E-mail: jcernicharo@cab.inta-csic.es, E-mail: brittany.gordon@ncf.edu, E-mail: shipman@ncf.edu [Division of Natural Sciences, New College of Florida, Sarasota, FL 34243 (United States)

    2014-03-20

    New laboratory data of ethyl mercaptan, CH{sub 3}CH{sub 2}SH, in the millimeter- and submillimeter-wave domains (up to 880 GHz) provided very precise values of the spectroscopic constants that allowed the detection of gauche-CH{sub 3}CH{sub 2}SH toward Orion KL. This identification is supported by 77 unblended or slightly blended lines plus no missing transitions in the range 80-280 GHz. A detection of methyl mercaptan, CH{sub 3}SH, in the spectral survey of Orion KL is reported as well. Our column density results indicate that methyl mercaptan is ≅ 5 times more abundant than ethyl mercaptan in the hot core of Orion KL.

  18. Molecular conformation changes in alkylthiol ligands as a function of size in gold nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Ramallo-Lopez, J.M.; Giovanetti, L.J.; Requejo, F.G. [Universidad Nacional de La Plata, Buenos Aires (Argentina); Isaacs, S.R.; Shon, Y.S. [Western Kentucky University, KY (United States); Salmeron, M. [Lawrence Berkeley National Laboratory, Berkeley, CA (United States)

    2006-07-01

    The binding of thiol molecules to gold, and in particular to gold nanoparticles (NP), is important in sensors, self-assembled monolayers and many other nanotechnological applications. For example, organic-thiolate s are extensively used as capping agents to prevent metal particle sintering and as ligands that can be functionalized to provide desirable chemical properties. An interesting feature of alkyl hydrocarbon chains is their flexibility, which allows them to change conformation to maximize space filling. This is driven by the inter-chain van der Waals nervy, which is considerably higher for longer chains and can be comparable to the stronger covalent bond of the S head with the Au. On the other hand, chain flexibility is facilitated by the easy formation of gauche distortions which require activation energies of only 0.16 eV. (author)

  19. Imaging phospholipid conformational disorder and packing in giant multilamellar liposome by confocal Raman microspectroscopy

    Science.gov (United States)

    Noothalapati, Hemanth; Iwasaki, Keita; Yoshimoto, Chikako; Yoshikiyo, Keisuke; Nishikawa, Tomoe; Ando, Masahiro; Hamaguchi, Hiro-o.; Yamamoto, Tatsuyuki

    2017-12-01

    Liposomes are closed phospholipid bilayer systems that have profound applications in fundamental cell biology, pharmaceutics and medicine. Depending on the composition (pure or mixture of phospholipids, presence of cholesterol) and preparation protocol, intra- and inter-chain molecular interactions vary leading to changes in the quality (order and packing) of liposomes. So far it is not possible to image conformational disorders and packing densities within a liposome in a straightforward manner. In this study, we utilized confocal Raman microspectroscopy to visualize structural disorders and packing efficiency within a giant multilamellar liposome model by focusing mainly on three regions in the vibrational spectrum (Csbnd C stretching, Csbnd H deformation and Csbnd H stretching). We estimated properties such as trans/gauche isomers and lateral packing probability. Interestingly, our Raman imaging studies revealed gel phase rich domains and heterogeneous lateral packing within the giant multilamellar liposome.

  20. Conformational preferences of γ-aminobutyric acid in the gas phase and in water

    Science.gov (United States)

    Song, Il Keun; Kang, Young Kee

    2012-09-01

    The conformational study of γ-aminobutyric acid (GABA) has been carried out at the M06-2X/cc-pVTZ level of theory in the gas phase and the SMD M06-2X/cc-pVTZ level of theory in water. In the gas phase, the folded conformation gG1 with gauche- and gauche+ conformations for the Cβsbnd Cα and Cγsbnd Cβ bonds, respectively, is found to be lowest in energy and enthalpy, which can be ascribed to the favored hyperconjugative n → π* interaction between the lone electron pair of the amine nitrogen atom and the Cdbnd O bond of the carboxylic group and the favored antiparallel dipole-dipole interaction between the Nsbnd H bond and the Cdbnd O bond. In addition, the intramolecular hydrogen bonds between the carboxylic group and the amine Nsbnd H group have contributed to stabilize some low-energy conformers. However, the most preferred conformation is found to be tG1 and more stable by 0.4 kcal/mol in ΔG than the conformer gG1, in which the favored entropic term due to the conformational flexibility and the other favored n → σ*, σ → σ*, and π → σ* interactions seem to play a role. The conformational preferences of the neutral GABA calculated by ΔG's are reasonably consistent with the populations deduced from FT microwave spectroscopy in supersonic jets combined with laser ablation. In water, the two folded conformers Gg and gG of the zwitterionic GABA are dominantly populated, each of which has the population of 47%, and the hydrogen bond between the ammonium Nsbnd H group and the lone electron pair of the Csbnd O- group seems to be crucial in stabilizing these conformers. Our calculated result that the folded conformers preferentially exist in water is consistent with the 1H NMR experiments in D2O.

  1. Weak intramolecular interaction effects on the torsional spectra of ethylene glycol, an astrophysical species

    Energy Technology Data Exchange (ETDEWEB)

    Boussessi, R., E-mail: rahma.boussesi@iem.cfmac.csic.es [Departamento de Química y Física Teóricas, I. Estructura de la Materia, IEM-CSIC, Serrano 121, Madrid 28006 (Spain); Laboratoire de Spectroscopie Atomique, Moléculaire et Applications-LSAMA LR01ES09, Faculté des sciences de Tunis, Université de Tunis El Manar, 2092 Tunis (Tunisia); Senent, M. L., E-mail: ml.senent@csic.es [Departamento de Química y Física Teóricas, I. Estructura de la Materia, IEM-CSIC, Serrano 121, Madrid 28006 (Spain); Jaïdane, N. [Laboratoire de Spectroscopie Atomique, Moléculaire et Applications-LSAMA LR01ES09, Faculté des sciences de Tunis, Université de Tunis El Manar, 2092 Tunis (Tunisia)

    2016-04-28

    An elaborate variational procedure of reduced dimensionality based on explicitly correlated coupled clusters calculations is applied to understand the far infrared spectrum of ethylene-glycol, an astrophysical species. This molecule can be classified in the double molecular symmetry group G{sub 8} and displays nine stable conformers, gauche and trans. In the gauche region, the effect of the potential energy surface anisotropy due to the formation of intramolecular hydrogen bonds is relevant. For the primary conformer, stabilized by a hydrogen bond, the ground vibrational state rotational constants are computed to be A{sub 0} = 15 369.57 MHz, B{sub 0} = 5579.87 MHz, and C{sub 0} = 4610.02 MHz corresponding to differences of 6.3 MHz, 7.2 MHz, and 3.5 MHz from the experimental parameters. Ethylene glycol displays very low torsional energy levels whose classification is not straightforward and requires a detailed analysis of the torsional wavefunctions. Tunneling splittings are significant and unpredictable due to the anisotropy of the potential energy surface PES. The ground vibrational state splits into 16 sublevels separated ∼142 cm{sup −1}. The splitting of the “G1 sublevels” was calculated to be ∼0.26 cm{sup −1} in very good agreement with the experimental data (0.2 cm{sup −1} = 6.95 MHz). Transitions corresponding to the three internal rotation modes allow assignment of previously observed Q branches. Band patterns, calculated between 362.3 cm{sup −1} and 375.2 cm{sup −1}, 504 cm{sup −1} and 517 cm{sup −1}, and 223.3 cm{sup −1} and 224.1 cm{sup −1}, that correspond to the tunnelling components of the v{sub 21} fundamental (v{sub 21} = OH-torsional mode), are assigned to the prominent experimental Q branches.

  2. Language Tasks and Mobile Technologies: A Paradigm Shift in Designing Task-Based CALL for Young Language Learners / Activités langagières et technologies mobiles : un changement de paradigme dans la conception des tâches en apprentissage des langues

    Directory of Open Access Journals (Sweden)

    Martine Pellerin

    2014-05-01

    activités langagières en aidant les jeunes apprenants à créer leur propre environnement d'apprentissage et des tâches langagières pertinentes, à s'autoévaluer et à réguler leur processus d'apprentissage linguistique. La recherche met aussi en évidence la façon dont l'utilisation des technologies mobiles contribue au remodelage d’approches basées sur les tâches qui reflètent les principes d'apprentissage fondés sur de nouvelles théories d'apprentissage ainsi que sur les théories socioculturelles de Vygotsky sur l’acquisition d’une seconde langue.

  3. Electronic Access to Justice: From Theory to Practice and Back Accès numérique à  la justice : allers-retours de la théorie à la pratique

    Directory of Open Access Journals (Sweden)

    Marco Velicogna

    2011-10-01

    Full Text Available Recent empirical researches are showing that e-justice systems are built linking and reshaping heterogeneous components, building blocks of technological, organizational and normative nature. The new comes not much from inventing out of the blue and developing from scratch but form reusing, copying, adapting and hooking together existing components. At the same time, new actors, such as technological partners and network providers make their appearance. Power and organizational borders alter, as ‘who-does-what’ changes in the translation of procedures from paper to digital and from one form of digital to another. Traditional ICT development and innovation management approaches have serious problems in coping with this complexity. Indeed, new theories are called for. Through the experience of several empirical case studies, this paper looks at e-justice dynamics and ramifications in the attempt to tackle its multi-faced complexity. The purpose is twofold: on the one hand, stimulating the academic discourse on a growingly relevant topic, on the other hand enriching the reflection of practitioners in the perspective of e-justice innovation to support access to justice -and appeal to court- focusing on the specific area of environmental matters.Les recherches empiriques récentes montrent que les systèmes de justice électronique (e-justice sont construits par la liaison et le remodelage de composants hétérogènes, de nature tant technologique qu’organisationnelle ou normative. La nouveauté résulte de la réutilisation, de la copie, de l’adaptation et de la mise ensemble de blocs préexistants. Dans le même temps, de nouveaux acteurs tels que les partenaires technologiques ou les fournisseurs de réseaux ont fait leur apparition.Les rapports de pouvoir et les cloisonnements organisationnels ont un impact, dans la mesure où le « qui fait quoi » change lorsque les procédures basculent du support papier vers le support numérique ou

  4. INTRODUCTION A National park is an area set aside by a national government for the preservation of the natural environment. The World Conservation Union defines a National park as a natural area designated to protect the ecological integrity of one or more ecosystems for present and future generations. In Pakistan, the earlier ecological studies were generally observational. The earlier studies, generally appeared in 1950’s, were confined to visual description of the vegetation, and no attempts were made to recognize community types and to correlate them with the relevant environmental factors. On the contrary, advanced multivariate techniques of ordination and cluster analysis had been routinely used in Europe and other parts of the world. There are numerous ordination methods accessible in plant bionetwork, some of which have been extensively used, e.g. Principal Component Analysis (PCA and Detrended Correspondence Analysis (DCA (Hill & Gauch, 1980, whereas some others only sporadically used (Zhang, 2004. A series of studies using different ordination techniques were carried out in Pakistan by Ahmad et al., 2009; Ahmad, 2009; Jabeen & Ahmad, 2009; Pirzada et al., 2009; Ahmad et al., 2010a, b; Ahmad, 2011. In Canonical Correspondence Analysis (CCA the floristic statistics and the environmental variables can be assimilated within the ordination (Kashian et al., 2003. Within the Ayubia National Park, the study area was the moist temperate forest in Rawalpindi, NE-Pakistan (Fig. 1, showing a high diversity of susceptible plant and animal species. The geographical location of the park is 330° 52' N and 730° 90' E (Farooque, 2002. The aim of this research was to quantify the vegetation in Ayubia National Park using ordination techniques and to determine the soilvegetation relationship to provide basic awareness for preservation of nationally significant native flora. A list of plant species present in the study area is provided in Table 1. Apart from their

    Directory of Open Access Journals (Sweden)

    Qurat Ul Ann

    2011-09-01

    Full Text Available The relationship between species diversity and overall community assemblage was identified in two differentzones in Ayubia National Park (Rawalpindi, NE-Pakistan which is recognized as protected area. CanonicalCorrespondence Analysis (CCA was used to find correlation of environmental variables with speciesabundance/richness. Results showed that in Zone 1 species were rather scattered due to the less availability oforganic matter and soil moisture as they occupy the less dense forest cover. Whereas Zone 2 showed theopposite trends. Finally the overall zones showed that maximum number of quadrats included Zone 2 speciesdue to a great forest cover with excess amount of organic matter and soil moisture. The study highlighted theimportance of dynamic nature and composition of vegetation and stressed the need of conservation of nativeflora for future generations.

  5. Unanticipated guest motion during a phase transition in a ferroelastic inclusion compound.

    Science.gov (United States)

    Hollingsworth, Mark D; Peterson, Matthew L; Pate, Kevin L; Dinkelmeyer, Brian D; Brown, Michael E

    2002-03-13

    Urea inclusion compounds (UICs) have been used as tools to understand ferroelastic domain switching and molecular recognition during crystal growth. Although the vast majority of UICs contain helical arrangements of host H-bonds, those containing guests with the formula X(CH(2))(6)Y (X, Y = Br, Cl, CN, NC) adopt an alternative P2(1)/n packing mode in which the host molecules exist as stacked loops of urea hexamers. Such structures may be further separated into two classes, ones distorted away from hexagonal symmetry along [100] (Br(CH(2))(6)Br, Br(CH(2))(6)Cl, and Cl(CH(2))(6)Cl) and those distorted along [001] (e.g. NC(CH(2))(6)CN). In each of these systems, guests exist as equilibrium mixtures of gauche conformers whose populations control the direction and magnitude of the observed distortion. Such UICs are potentially ferroelastic, but the n-glide requires that domains are not related by a simple rotation-translation mechanism as in the helical systems. Ferroelastic (degenerate) domain reorientation would necessitate a large-scale reorganization of the urea framework and rupture of numerous H-bonds. Coupled with distortions of 2 to 10%, this mechanism-based barrier to domain switching has precluded observation of this phenomenon. To prepare ferroelastic UICs with minimal distortions from hexagonal symmetry, attempts were made to form solid solutions of UICs containing guests from the two classes. This failed, however: solid solution formation of the stacked loop form is usually possible within a series (e.g. with Cl(CH(2))(6)Cl and Br(CH(2))(6)Br), but not between series (e.g. Cl(CH(2))(6)Cl and NC(CH(2))(6)CN). Crystals of Cl(CH(2))(6)CN/urea, in which a single guest contains substituents from each class, are distorted along [001] by only 0.5% from hexagonal symmetry at 298 K and exhibit ferroelastic domain reorientation at high forces. At -66 degrees C, Cl(CH(2))(6)CN/urea undergoes a topotactic phase transition that is unexpectedly nontopochemical. The

  6. Lésions bulleuses et purpuriques unilatérales: pathomimie cutanée

    Science.gov (United States)

    Zinoun, Mouna; Chiheb, Soumia; Marnissi, Farida; Kadiri, Nadia; Benchikhi, Hakima

    2015-01-01

    La pathomimie cutanée est une forme particulière de troubles factices relativement rare, et constitue l'un des problèmes les plus complexes pour le dermatologue. Nous rapportons un cas de pathomimie révélée par des lésions cutanées unilatérales, mimant une brûlure. Une jeune femme de 27 ans, était suivie depuis 4 ans pour une dépression. Elle a présenté 15j avant sa 1ère hospitalisation un placard inflammatoire du sein gauche compliqué de lésions bulleuses et d’érosions superficielles. La biopsie cutanée avait montré une dermite non spécifique. Une cicatrisation rapide sous traitement local a été notée. Elle a présenté 10 jours plus tard de nouvelles lésions similaires étagées au membre inférieur gauche, évoluant vers le décollement bulleux spontané. La biopsie cutanée avait montré un décollement bulleux jonctionnel et des foyers de nécrose ischémique. L'IFD était négative. Devant les données anamnestiques, cliniques, la négativité du bilan paraclinique, et la guérison des lésions sous pansements occlusifs seuls, le diagnostic de pathomimie a été évoqué et retenu. La patiente a été adressée en psychiatrie où une thérapie cognitivo-comportementale a été préconisée. Notre observation correspond à un tableau de pathomimie de présentation clinique particulière par sa localisation unilatérale et son caractère bulleux. Chez notre patiente qui est droitière, la localisation unilatérale gauche sur des zones accessibles, l'absence de lésions spécifiques à l'examen histologique, la cicatrisation rapide des lésions sous traitement local occlusif seul et leur récurrence malgré des soins adaptés étaient en faveur d'une pathologie factice. Néanmoins, la localisation au niveau des seins peut être très déroutante. Le caractère bulleux des lésions dans le cadre d'une pathomimie a été rarement rapporté. Dans notre cas, la pathomimie s'associe à des troubles anxieux et dépressifs très importants

  7. Le carcinome parathyroïdien: à propos d’un cas et revue de la literature

    Science.gov (United States)

    kolsi, Naourez; Jellali, Sondos; Koubaa, Jamel

    2017-01-01

    Le carcinome parathyroïdien est une tumeur maligne, très rare, de la glande parathyroïde. Cliniquement, ce cancer se présente souvent par un tableau d'hyperparathyroïdie primaire sévère. Le diagnostic est histologique mais n'est pas toujours aisé. Le traitement est basé sur la chirurgie. Femme âgée de 59 ans, aux antécédents d'hypertension artérielle, et de lithiases rénales récidivantes, consultait pour des douleurs osseuses diffuses avec asthénie. L'examen du cou a trouvé une tuméfaction basi-cervicale dure et à bord inférieur non palpable. A la biologie: hypercalcémie à 4,1 mmol/l, une hyperparathyroïdie avec valeur de parathormone (PTH) très élevée à 1088 pg/ml soit 13 fois la normale. La scintigraphie au Technétium-99m-sestamibi a montré une plage de fixation anormale de MIBI en projection de la parathyroïde inférieure gauche. Une parathyroïdectomie inférieure gauche, avec évidement médiastino-récurrentiel homolatéral ont été réalisés. Les suites opératoires étaient marquées par la normalisation de la calcémie et de la PTH. L'anatomopathologie était en faveur d'un carcinome parathyroïdien. Le diagnostic de carcinome parathyroïdien est généralement établi sur la conjonction de signes radiologiques biologiques et histologiques. La gravité de cette pathologie est due à l'hypercalcémie sévère et au risque de récidive et de métastases à distance justifiant la surveillance prolongée. PMID:28819506

  8. Structural variability in Cu(I) and Ag(I) coordination polymers with a flexible dithione ligand: Synthesis, crystal structure, microbiological and theoretical studies

    Energy Technology Data Exchange (ETDEWEB)

    Beheshti, Azizolla, E-mail: a.beheshti@scu.ac.ir [Department of Chemistry, Faculty of Sciences, Shahid Chamran University of Ahvaz, Ahvaz (Iran, Islamic Republic of); Nozarian, Kimia; Babadi, Susan Soleymani; Noorizadeh, Siamak [Department of Chemistry, Faculty of Sciences, Shahid Chamran University of Ahvaz, Ahvaz (Iran, Islamic Republic of); Motamedi, Hossein [Department of Biology, Faculty of Sciences, Shahid Chamran University of Ahvaz, Ahvaz (Iran, Islamic Republic of); Mayer, Peter [LMU München Department Chemie, Butenandtstr 5-13, D-81377 München (Germany); Bruno, Giuseppe [Dipartimento di Chimica Inorganica, Università di Messina, Vill. S. Agata, Salita Sperone 31, 98166 Messina (Italy); Rudbari, Hadi Amiri [Faculty of Chemistry, University of Isfahan, Isfahan 81746-73441 (Iran, Islamic Republic of)

    2017-05-15

    Two new compounds namely [Cu(SCN)(µ-L)]{sub n} (1) and ([Ag (µ{sub 2}-L)](ClO{sub 4})){sub n} (2) have been synthesized at room temperature by one-pot reactions between the 1,1-(1,4-butanediyl)bis(1,3-dihydro-3-methyl-1H-imidazole- 2-thione) (L) and appropriate copper(I) and silver(I) salts. These polymers have been characterized by single crystal X-ray diffraction, XRPD, TGA, elemental analysis, infrared spectroscopy, antibacterial activity and scanning probe microscopy studies. In the crystal structure of 1, copper atoms have a distorted trigonal planar geometry with a CuS{sub 2}N coordination environment. Each of the ligands in the structure of 1 acting as a bidentate S-bridging ligand to form a 1D chain structure. Additionally, the adjacent 1D chains are interconnected by the intermolecular C-H…S interactions to create a 2D network structure. In contrast to 1, in the cationic 3D structure of 2 each of the silver atoms exhibits an AgS{sub 4} tetrahedral geometry with 4-membered Ag{sub 2}S{sub 2} rings. In the structure of 2, the flexible ligand adopts two different conformations; gauche-anti-gauche and anti-anti-anti. The antibacterial studies of these polymers showed that polymer 2 is more potent antibacterial agent than 1. Scanning probe microscopy (SPM) study of the treated bacteria was carried out to investigate the structural changes cause by the interactions between the polymers and target bacteria. Theoretical study of polymer 1 investigated by the DFT calculations indicates that observed transitions at 266 nm and 302 nm in the UV–vis spectrum could be attributed to the π→π* and MLCT transitions, respectively. - Graphical abstract: Two new Cu(I) and Ag(I) coordination polymers have been have been synthesized by one-pot reactions. Copper complex has a 2D non-covalent structure, but silver compound is a 3D coordination compound. These compounds have effective antibacterial activity. - Highlights: • Cu(I) and Ag(I) based coordination polymers

  9. On the turn-inducing properties of asparagine: the structuring role of the amide side chain, from isolated model peptides to crystallized proteins.

    Science.gov (United States)

    Habka, S; Sohn, W Y; Vaquero-Vara, V; Géléoc, M; Tardivel, B; Brenner, V; Gloaguen, E; Mons, M

    2018-01-31

    Asparagine (Asn) is a powerful turn-inducer residue, with a large propensity to occupy the second position in the central region of β-turns of proteins. The present work aims at investigating the role of a local anchoring between the Asn side chain and the main chain in this remarkable property. For this purpose, the H-bonding patterns of an asparagine residue in an isolated protein chain fragment forming a γ- or a β-turn have been determined using IR/UV double resonance gas phase spectroscopy on laser-desorbed, jet-cooled short models in conjunction with relevant quantum chemistry calculations. These gas phase data provide evidence for an original double anchoring linking the Asn primary amide side chain (SC), which adopts a gauche+ rotameric form, to its main chain (MC) local environment. From both IR spectroscopic evidence (H-bond induced red shifts) and quantum chemistry, Asn SC is found to behave as a stronger H-bond acceptor than donor, resulting in stronger MC→SC H-bonds than SC→MC ones. These gas phase structural data, relevant to a hydrophobic environment, have been used as a reference to assess the anchoring taking place in high resolution crystallized proteins of the Protein Data Bank. This approach reveals that, when the SC adopts a gauche+ orientation, the stronger MC→SC bonds are preserved in many cases whereas the SC→MC bonds are always disrupted, in qualitative agreement with the gas phase ranking of these interactions. Most interestingly, when Asn occupies the second position of central part of a β-turn (i.e., the very turn-inducer position), the MC→SC H-bonds are also disrupted and replaced by a water-mediated SC to MC anchoring. Owing to the specific features of the hydrated Asn side chain, we propose that it could be a turn precursor structure, able to facilitate turn formation in the early events of the folding process.

  10. The Enantiomers of 4-Amino-3-fluorobutanoic Acid as Substrates for γ-Aminobutyric Acid Aminotransferase. Conformational Probes for GABA Binding†

    Science.gov (United States)

    Clift, Michael; Ji, Haitao; Deniau, Gildas P.; O’Hagan, David; Silverman, Richard B.

    2008-01-01

    γ-Aminobutyric acid aminotransferase (GABA-AT), a pyridoxal 5’-phosphate dependent enzyme, catalyzes the degradation of the inhibitory neurotransmitter γ-aminobutyric acid (GABA) to succinic semialdehyde with concomitant conversion of pyridoxal 5’-phosphate (PLP) to pyridoxamine 5’-phosphate (PMP). The enzyme then catalyzes the conversion of α-ketoglutarate to the excitatory neurotransmitter L-glutamate. Racemic 4-amino-3-fluorobutanoic acid (3-F-GABA) was shown previously to act as a substrate for GABA-AT, not for transamination, but for HF elimination. Here we report studies of the reaction catalyzed by GABA-AT on (R)- and (S)-3-F-GABA. Neither enantiomer is a substrate for transamination. Very little elimination from the (S)-enantiomer was detected using a coupled enzyme assay; The rate of elimination of HF from the (R)-enantiomer is at least 10 times greater than that for the (S)-enantiomer. The (R)-enantiomer is about 20 times more efficient as a substrate for GABA-AT catalyzed HF elimination than GABA is a substrate for transamination. The (R)-enantiomer also inhibits the transamination of GABA 10 times more effectively than the (S)-enantiomer. Using a combination of computer modeling and the knowledge that vicinal C-F and C-NH3+ bonds have a strong preference to align gauche rather than anti to each other, it is concluded that on binding of free 3-F-GABA to GABA-AT the optimal conformation places the C-NH3+ and C-F bonds gauche in the (R)-enantiomer but anti in the (S)-enantiomer. Furthermore, the dynamic binding process and the bioactive conformation of GABA bound to GABA-AT have been inferred based on the different biological behavior of the two enantiomers of 3-F-GABA when they bind to the enzyme. The present study suggests that the C-F bond can be utilized as a conformational probe to explore the dynamic binding process and provide insight into the bioactive conformation of substrates, which cannot be easily determined by other biophysical

  11. Space use optimisation and sustainability-environmental comparison of international cases.

    Science.gov (United States)

    de Wilde, Sebastiaan; van den Dobbelsteen, Andy

    2004-11-01

    As a follow-up to our first paper in this journal, this paper discusses projects involving intensive and multiple use of space recently completed or still being developed around railway stations in London (Broadgate and Canary Wharf), Paris (Seine Rive Gauche and La Défense) and Amsterdam (Zuidas and Bijlmer). The cases were compared on the basis of spatial, functional and environmental indicators, as treated in our first paper. The environmental performance of each of the cases was determined through comparison with a theoretic reference project for an equal number of users, yet with average West-European urban values for spatial, functional and environmental properties. The case studies revealed that a high floor space index is easily achievable in urban plans, implying efficient use of land and preservation of green area outside the city. For a mono-functional office area it is easier to achieve a high FSI than for a functionally diverse area with, e.g. apartments and shops. Therefore, with respect to a reference functionally equal to the cases, the predominant office character of Canary Wharf, Broadgate and La Défense results in good environmental performance. However, on the basis of a functionally diverse reference, for which monofunctional cases were enlarged with additional area for housing and amenities, the varied areas of Zuidas and Seine Rive Gauche perform best. With respect to average urban plans, the cases achieved environmental improvement of factor 1.5. This performance is restricted by the energy consumption of buildings, which has by far the most influence on the end result. The impact of stacking on the use of building materials and energy consumption of buildings is limited, and specific sustainability measures on the building scale were not involved in the calculations. The environmental benefits of intensive and multiple use of space are mainly demonstrated by the great improvement factors for the green area preserved and transport fuel

  12. A Comparative Density Functional Theory and Density Functional Tight Binding Study of Phases of Nitrogen Including a High Energy Density Material N8

    Directory of Open Access Journals (Sweden)

    Nicholas Capel

    2015-11-01

    Full Text Available We present a comparative dispersion-corrected Density Functional Theory (DFT and Density Functional Tight Binding (DFTB-D study of several phases of nitrogen, including the well-known alpha, beta, and gamma phases as well as recently discovered highly energetic phases: covalently bound cubic gauche (cg nitrogen and molecular (vdW-bound N8 crystals. Among several tested parametrizations of N–N interactions for DFTB, we identify only one that is suitable for modeling of all these phases. This work therefore establishes the applicability of DFTB-D to studies of phases, including highly metastable phases, of nitrogen, which will be of great use for modelling of dynamics of reactions involving these phases, which may not be practical with DFT due to large required space and time scales. We also derive a dispersion-corrected DFT (DFT-D setup (atom-centered basis parameters and Grimme dispersion parameters tuned for accurate description simultaneously of several nitrogen allotropes including covalently and vdW-bound crystals and including high-energy phases.

  13. Littérature progressive du français avec 600 activités : niveau intermédiaire

    CERN Document Server

    Blondeau, Nicole; Né, Marie-Françoise

    2004-01-01

    Une organisation claire : le texte littéraire, une courte biographie de l'auteur et des notes explicatives sur la page de gauche; des activités guidées de découverte et d'exploitation sur la page de droite la progression : les textes sont classés par ordre chronologique. Les activitées de lecture et d'analyse constituent un véritable parcours d'aprentissage le choix des textes : du Moyen Age à nos jours, avec une priorité accordée à la littérature contemporaine (XIXe et XXe), des textes parmi les plus représentatifs de la littérature française, avec une ouverture sur la littérature francophone l'appareil pédagogique propose une approche facilitant la découverte et la compréhension de l'histoire littéraire, le repérage des genres et la portée des idées un usage souple : pour la classe ou en auto-apprentissage A découvrir dans cette deuxième édition revue et augmentée:

  14. Vocabulaire progressif du français avec 250 exercices : niveau débutant

    CERN Document Server

    Miquel, Claire

    2002-01-01

    Le Vocabulaire progressif du français est un ouvrage destiné aux étudiants adolescents et adultes de niveaux débutant et faux débutant. Conçu pour être utilisé comme complément de méthode en classe, ou comme guide pour un auto-apprentissage, il comprend : - sur la page de gauche, une leçon de vocabulaire : les mots sont mis en contexte dans des phrases, des histoires, des dialogues, ou bien encore mis en scène grâce à des illustrations - sur la page de droite, des exercices d'application et des activités de communication classés par ordre de difficulté croissante. Le lexique est présenté de façon thématique. Chaque chapitre est constitué de plusieurs séquences assurant un enrichissement progressif. Ce manuel aborde un vocabulaire vivant qui correspond à la réalité des Français d'aujourd'hui. Il constitue une véritable initiation aux codes culturels. Les corrigés sont disponibles dans un livret séparé (ISBN 2090338792)

  15. Littérature progressive du français avec 600 activités : niveau débutant

    CERN Document Server

    Blondeau, Nicole; Né, Marie-Françoise

    2004-01-01

    Une organisation claire : le texte littéraire, une courte biographie de l'auteur et des notes explicatives sur la page de gauche; des activités guidées de découverte et d'exploitation sur la page de droite la progression : les textes sont classés par ordre chronologique. Les activitées de lecture et d'analyse constituent un véritable parcours d'aprentissage le choix des textes : du Moyen Age à nos jours, avec une priorité accordée à la littérature contemporaine (XIXe et XXe), des textes parmi les plus représentatifs de la littérature française, avec une ouverture sur la littérature francophone l'appareil pédagogique propose une approche facilitant la découverte et la compréhension de l'histoire littéraire, le repérage des genres et la portée des idées un usage souple : pour la classe ou en auto-apprentissage A découvrir dans cette deuxième édition revue et augmentée:

  16. Constant-pH molecular dynamics using stochastic titration

    Science.gov (United States)

    Baptista, António M.; Teixeira, Vitor H.; Soares, Cláudio M.

    2002-09-01

    A new method is proposed for performing constant-pH molecular dynamics (MD) simulations, that is, MD simulations where pH is one of the external thermodynamic parameters, like the temperature or the pressure. The protonation state of each titrable site in the solute is allowed to change during a molecular mechanics (MM) MD simulation, the new states being obtained from a combination of continuum electrostatics (CE) calculations and Monte Carlo (MC) simulation of protonation equilibrium. The coupling between the MM/MD and CE/MC algorithms is done in a way that ensures a proper Markov chain, sampling from the intended semigrand canonical distribution. This stochastic titration method is applied to succinic acid, aimed at illustrating the method and examining the choice of its adjustable parameters. The complete titration of succinic acid, using constant-pH MD simulations at different pH values, gives a clear picture of the coupling between the trans/gauche isomerization and the protonation process, making it possible to reconcile some apparently contradictory results of previous studies. The present constant-pH MD method is shown to require a moderate increase of computational cost when compared to the usual MD method.

  17. Grammaire progressive du français niveau intermédiaire

    CERN Document Server

    Grégoire, Maïa

    2017-01-01

    Quatrième édition de l'ouvrage de Grammaire de français langue étrangère (FLE), niveau intermédiaire, dans la collection Progressive du français destiné aux grands adolescents et adultes. Ce qui fait le succès de cet ouvrage de Grammaire: une organisation claire : la leçon de grammaire sur la page de gauche; les exercices d'entraînement sur la page de droite 52 chapitres présentant les points généralement abordés aux niveaux A2 et B1 du Cadre européen commun de référence pour les langues un apprentissage progressif : il suit la progression naturelle des méthodes de français un usage souple : pour la classe ou en auto-apprentissage une préparation adaptée aux certifications : un entreînement efficace pour mieux réussir aux examens NOUVEAU! Appli-web de la Grammaire progressive du français incluse Pour s'entraîner et s'évaluer en ligne en sollicitant toutes les compétences écrites et orales : près de 300 exercices interactifs avec dialogues, instructions, exemples et corrigés ora...

  18. Grammaire progressive du français corrigés : niveau intermédiaire

    CERN Document Server

    Thiévenaz, Odile

    2017-01-01

    Quatrième édition des corrigés de l'ouvrage de Grammaire de français langue étrangère (FLE), niveau intermédiaire, dans la collection Progressive du français destiné aux grands adolescents et adultes. Ce qui fait le succès de cet ouvrage de grammaire: Une organisation claire : la leçon de grammaire sur la page de gauche, les exercices d'entraînement sur la page de droite 52 chapitres présentant les points généralement abordés aux niveaux A2 et B1 du Cadre européen commun de référence pour les langues Un apprentissage progressif : il suit la progression naturelle des méthodes de français Un usage souple : pour la classe ou en auto-apprentissage Une préparation adaptée aux certifications : un entraînement efficace pour mieux réussir aux examens NOUVEAU!​ Appli-Web de la Grammaire progressive du français Pour s'entraîner et s'évaluer en ligne en sollicitant toutes les compétences écrites et orales: près de 300 exercices interactifs avec dialogues, instructions, exemples et corri...

  19. Photothermal microfluidic cantilever deflection spectroscopy reflecting clustering mechanism of ethanol water mixtures

    Science.gov (United States)

    Ghoraishi, Maryam; Hawk, John; Thundat, Thomas

    Aqueous mixture of alcohol is a typical prototype for biomolecules, micelle formation, and structural stability of proteins. Therefore, Short chain alcohols such as EtOH have been used as a simple model for understanding of more complex aqueous biomolecules. Here we study vibrational energy peaks of EtOH water binary mixtures using micromechanical calorimetric spectroscopy using bimaterial microfluidic cantilevers (BMC). The IR spectra of EtOH-water are experimentally collected employing a BMC as concentration of EtOH changes from 20-100 wt%. As concentration of EtOH varies in the mixture, considerable shifts in the wavenumber at IR absorption peak maxima are reported. The experimentally measured shifts in the wavenumber at IR absorption peak maxima are related to changes in dipole moment (μ) of EtOH at different concentration. The relationship between IR absorption wavenumber for both anti and gauche conformers of EtOH, and inverse dipole moment, 1/ μ, of EtOH at different concentrations follows a power law dependence. Our technique offers a platform to investigate dipole effect on molecular vibrations of mixtures in confined picoliter volumes, previously unexplored with other analytical techniques due to limitations of volume under study.

  20. [1,4-Bis(diphenylphosphanylbutane-κ2P,P′]dibromidopalladium(II

    Directory of Open Access Journals (Sweden)

    Kwang Ha

    2014-02-01

    Full Text Available In the title complex, [PdBr2(C28H28P2], the PdII ion has a distorted cis-Br2P2 square-planar coordination geometry defined by two P atoms from the chelating 1,4-bis(diphenylphosphanylbutane ligand and two Br− anions. The four phenyl rings are inclined to the least-squares plane of the PdBr2P2 unit [maximum deviation = 0.1294 (7 Å], making dihedral angles of 66.3 (2, 87.2 (2, 68.8 (2 and 86.8 (2°. The butylene chain is in a gauche conformation, with a C—C—C—C torsion angle of 57.0 (8°. Intermolecular C—H...Br hydrogen bonds link the complex molecules into supramolecular layers in the ab plane. Weak π–π interactions, both intra- and intermolecular [shortest inter-centroid distance = 4.598 (5 Å], are also noted in the three-dimensional architecture.

  1. Communication progressive du français avec 320 exercices : niveau débutant

    CERN Document Server

    Miquel, Claire

    2013-01-01

    Ce qui fait le succès de cete ouvrage de communication: Une organisation claire: la leçon sur la page de gauche; les exercices et les activités communicatives sur la page de droite 40 fiches présentant les points généralement abordés au niveau A1 du Cadre européen commun de référence pour les langues Un apprentissage progressif: il suit la progression naturelle des méthodes de français Un usage souple: pour la classe ou en auto-apprentissage Une préparation adaptée aux certifications: un entrainement efficace pour mieux réussir aux examens A découvrir dans cette deuxième édition revue et augmentée: Un CD audio avec 69 documents sonores Un test d'évaluation avec ses corrigés Des illustrations pédagogiques acutelles et colorées 50 nouveaux exercices. Un livret de corrigés est proposé à part (ISBN 978-209-038133-7).

  2. Communication progressive du français avec 320 exercices : niveau débutant : corrigés

    CERN Document Server

    Miquel, Claire

    2013-01-01

    Ce qui fait le succès de cet ouvrage de communication: Une organisation claire: la leçon sur la page de gauche; les exercices et les activités communicatives sur la page de droite 40 fiches présentant les points généralement abordés au niveau A1 du Cadre européen commun de référence pour les langues Un apprentissage progressif: il suit la progression naturelle des méthodes de français Un usage souple: pour la classe ou en auto-apprentissage Une préparation adaptée aux certifications: un entrainement efficace pour mieux réussir aux examens A découvrir dans cette deuxième édition revue et augmentée: Un CD audio avec 69 documents sonores Un test d'évaluation avec ses corrigés Des illustrations pédagogiques acutelles et colorées 50 nouveaux exercices. Communication Progressive du français niveau débutant, 2ème édition (ISBN 978-209-038132-0).

  3. Epanchement pleuro-péricardique liquidien révélant un lymphome lymphoblastique

    Science.gov (United States)

    N'goran, Yves N'da Kouakou; Soya, Kossa Esaïe; Beossin, Sylvanus Koui; Angoran, Ines; Traore, Fatou; Tano, Micesse; Afassinou, Yaovi; Ekou, Arnaud; Koffi, Florent; Yao, Hermann; Kramoh, Euloge Kouadio; Kakou, Maurice Guikahue

    2014-01-01

    L'atteinte cardiaque au cours des lymphomes lymphoblastiques est rare. Il s'agissait d'un patient de 17 ans de race noire qui a été admis pour une douleur médiothoracique. Le patient avait des signes d'insuffisance cardiaque droite; un syndrome d’épanchement pleural liquidien gauche; des adénopathies superficielles et une splénomégalie de type IV de Hackett. La biopsie ganglionnaire a été réalisée pour la confirmation du diagnostic par analyse histologique et immuno-histochimique. Des ponctions pleurale et péricardique ont été effectuées. Le patient a été confié au service d'oncologie pédiatrique pour la chimiothérapie. L’évolution a été marquée par le décès du patient 18 jours après. La manifestation cardiaque est une entité rare et très souvent méconnue.la confirmation histologique est parfois difficile à obtenir du vivant de la plupart des patients. Le pronostic est souvent réservé à court terme. PMID:25419294

  4. LHC gets the ball rolling

    CERN Multimedia

    2007-01-01

    1. The multidisciplinary team responsible for the RF ball project to check the interconnections. From left to right: Rhodri Jones (AB/BI), Eva Calvo (AB/BI), Francesco Bertinelli (AT/MCS), Sonia Bartolome Jimenez (TS/IC), Sylvain Weisz (TS/IC), Paul Cruikshank (AT/VAC), Willemjan Maan (AT/VAC), Alain Poncet (AT/MCS), Marek Gasior (AB/BI).2. During the tests the ball is inserted very carefully into the vacuum chamber.1. Le groupe pluridisciplinaire qui a mené le projet de balle RF pour vérifier les interconnexions avec, de gauche à droite, Rhodri Jones (AB/BI), Eva Calvo (AB/BI), Francesco Bertinelli (AT/MCS), Sonia Bartolome Jimenez (TS/IC), Sylvain Weisz (TS/IC), Paul Cruikshank (AT/VAC), Willemjan Maan (AT/VAC), Alain Poncet (AT/MCS) et Marek Gasior (AB/BI).2. Lors des tests, la balle est insérée dans la chambre à vide avec beaucoup de précaution.

  5. Effects of molecular and lattice structure on the thermal behaviours of some long chain length potassium(I) n-alkanoates

    Science.gov (United States)

    Nelson, Peter N.; Ellis, Henry A.; Taylor, Richard A.

    2014-01-01

    Lattice structures and thermal behaviours for some long chain potassium carboxylates (nc = 8-18, inclusive) are investigated using Fourier Transform Infrared spectroscopy, X-ray Powder Diffraction, Solid State spin decoupled 13C NMR spectroscopy, Differential Scanning Calorimetry and Thermogravimetry. The measurements show that the carboxyl groups are coordinated to potassium atoms via asymmetric chelating bidentate bonding, with extensive carboxyl intermolecular interactions to yield tetrahedral metal centers, irrespective of chain length. Furthermore, the hydrocarbon chains are crystallized in the fully extended all-trans configuration and are arranged as non-overlapping lamellar bilayer structures with closely packed methyl groups from opposite layers. Additionally, odd-even alternation, observed in density and methyl group chemical shift, is ascribed to the relative vertical distances between layers in the bilayer, that are not in the same plane. Therefore, for even chain homologues, where this distances is less than for odd chain adducts, more intimate packing is indicated. The phase sequences for all compounds show several reversible crystal-crystal transition associated with kinetically controlled gauche-trans isomerism of the polymethylene chains which undergo incomplete fusion when heated to the melt. The compounds degrade above 785 K to yield carbon dioxide, water, potassium oxide and an alkene.

  6. E uma rosa se abre: a guerra e a flor na poesia de Drummond

    Directory of Open Access Journals (Sweden)

    Valéria Daiane Soares Rodrigues

    2013-08-01

    Full Text Available Carlos Drummond de Andrade, em A Rosa do Povo (1945 articula, por meio da palavra e da criação de um “eu” lírico habitante de um mundo em guerra, a construção de uma imagem, imbuída de teor histórico, do Brasil dos anos finais da 2ª guerra mundial. Os versos traduzem a experiência do Drummond gauche, angustiado pelos problemas do seu tempo, em que a individualidade advinda da fragmentação do homem moderno é marca do conflito entre o “eu” lírico e o mundo. O poeta descreve de forma melancólica a degeneração das coisas e dos homens, em meio à consciência paralisante e a falta de perspectivas. A força que emerge do símbolo da rosa respalda o acento poético do Itabirano: a destruição dos valores provocados pela morte e pelo derramar de sangue contrasta com o brotar da flor no asfalto.  Do chão forrado de cadáveres, emerge uma rosa, numa representação da resistência humana.

  7. Caminhos para o parlamento: candidatos e eleitos nas eleições para deputado federal em 2006

    Directory of Open Access Journals (Sweden)

    Renato Monseff Perissinotto

    2009-06-01

    Full Text Available Dans cet article, on cherche à préciser quelles variables ont le plus incidé sur les chances de victoire des candidats à l'élection fédérale de 2006. À partir des données fournies par le Supérieur Tribunal Électoral, on a examiné, tout d'abord, la présence de corrélations statistiquement significatives entre, d'un côté, le sexe, l'âge, la profession, la scolarité et les coûts de campagne, et de l'autre, le résultat obtenu par le candidat - élu ou non élu. Ensuite, on présente un modèle de régression logistique binaire afin de mesurer le vrai impact de chacune de ces variables sur le succès du candidat. Ces procédés ont été appliqués aux partis de droite, centre et gauche. On conclut que le fait d'être un homme politique professionnel est la variable la plus importante pour assurer le succès électoral du candidat.

  8. Revisiting imidazolium based ionic liquids: Effect of the conformation bias of the [NTf2] anion studied by molecular dynamics simulations

    Science.gov (United States)

    Neumann, Jan; Golub, Benjamin; Odebrecht, Lisa-Marie; Ludwig, Ralf; Paschek, Dietmar

    2018-05-01

    We study ionic liquids composed of 1-alkyl-3-methylimidazolium cations and bis(trifluoromethyl-sulfonyl)imide anions ([CnMIm][NTf2]) with varying chain-length n = 2, 4, 6, 8 by using molecular dynamics simulations. We show that a reparametrization of the dihedral potentials as well as charges of the [NTf2] anion leads to an improvement of the force field model introduced by Köddermann, Paschek, and Ludwig [ChemPhysChem 8, 2464 (2007)] (KPL-force field). A crucial advantage of the new parameter set is that the minimum energy conformations of the anion (trans and gauche), as deduced from ab initio calculations and Raman experiments, are now both well represented by our model. In addition, the results for [CnMIm][NTf2] show that this modification leads to an even better agreement between experiment and molecular dynamics simulation as demonstrated for densities, diffusion coefficients, vaporization enthalpies, reorientational correlation times, and viscosities. Even though we focused on a better representation of the anion conformation, also the alkyl chain-length dependence of the cation behaves closer to the experiment. We strongly encourage to use the new NGOLP (Neumann, Golub, Odebrecht, Ludwig, Paschek) force field for the [NTf2] anion instead of the earlier KPL parameter set for computer simulations aiming to describe the thermodynamics, dynamics, and also structure of imidazolium-based ionic liquids.

  9. Expanding the peptide beta-turn in alphagamma hybrid sequences: 12 atom hydrogen bonded helical and hairpin turns.

    Science.gov (United States)

    Chatterjee, Sunanda; Vasudev, Prema G; Raghothama, Srinivasarao; Ramakrishnan, Chandrasekharan; Shamala, Narayanaswamy; Balaram, Padmanabhan

    2009-04-29

    Hybrid peptide segments containing contiguous alpha and gamma amino acid residues can form C(12) hydrogen bonded turns which may be considered as backbone expanded analogues of C(10) (beta-turns) found in alphaalpha segments. Exploration of the regular hydrogen bonded conformations accessible for hybrid alphagamma sequences is facilitated by the use of a stereochemically constrained gamma amino acid residue gabapentin (1-aminomethylcyclohexaneacetic acid, Gpn), in which the two torsion angles about C(gamma)-C(beta) (theta(1)) and C(beta)-C(alpha) (theta(2)) are predominantly restricted to gauche conformations. The crystal structures of the octapeptides Boc-Gpn-Aib-Gpn-Aib-Gpn-Aib-Gpn-Aib-OMe (1) and Boc-Leu-Phe-Val-Aib-Gpn-Leu-Phe-Val-OMe (2) reveal two distinct conformations for the Aib-Gpn segment. Peptide 1 forms a continuous helix over the Aib(2)-Aib(6) segment, while the peptide 2 forms a beta-hairpin structure stabilized by four cross-strand hydrogen bonds with the Aib-Gpn segment forming a nonhelical C(12) turn. The robustness of the helix in peptide 1 in solution is demonstrated by NMR methods. Peptide 2 is conformationally fragile in solution with evidence of beta-hairpin conformations being obtained in methanol. Theoretical calculations permit delineation of the various C(12) hydrogen bonded structures which are energetically feasible in alphagamma and gammaalpha sequences.

  10. Role of calcium in phosphoinositide metabolism and inhibition of norepinephrine transport into synaptic vesicles by amphetamine analogs

    International Nuclear Information System (INIS)

    Knepper, S.M.

    1985-01-01

    Norepinephrine-(NE) and calcium ionophore A23187-stimulated phosphoinositide (PIn) metabolism in rat brain slices was studied under varying calcium conditions. Tissue was labelled with 3 H-myo-inositol and 3 H-inositol phosphates (IPn), products of PIn metabolism were measured. In the absence of media calcium the response to NE was decreased while that to A23187 was little affected A23187 can release calcium from intracellular stores. Basal and stimulated accumulation of 3 H-IPn was reversibly antagonized with EGTA by addition of calcium. Using calcium buffers, approximately 10 -7 M free calcium was required to support hydrolysis. Free intracellular calcium is maintained at approximately this level. Thus calcium is required for PIn hydrolysis but appears to play a permissive role, basal levels being sufficient to support metabolism. Conformationally-defined (rigid) and -restricted (semi-rigid) analogs of the most stable conformations of amphetamine, antiperiplanar (exo) and gauche (endo), were utilized to probe the conformational requirements of vesicular NE transport. Analogs tested were 2-aminotetralin (2AT), 3-methyltetrahydroisoquinoline, anti- and syn-9-aminobenzobicyclo[2.2.1]heptene, and endo and exo conformers of 2-aminobenzobicyclo[2.2.1]heptene and 2-aminobenzobicyclo[2.2.2]octene

  11. Extraordinary Mechanism of the Diels-Alder Reaction: Investigation of Stereochemistry, Charge Transfer, Charge Polarization, and Biradicaloid Formation.

    Science.gov (United States)

    Sexton, Thomas; Kraka, Elfi; Cremer, Dieter

    2016-02-25

    The Diels-Alder reaction between 1,3-butadiene and ethene is investigated from far-out in the entrance channel to the very last step in the exit channel thus passing two bifurcation points and extending the range of the reaction valley studied with URVA (Unified Reaction Valley Approach) by 300% compared to previous studies. For the first time, the pre- and postchemical steps of the reaction are analyzed at the same level of theory as the actual chemical processes utilizing the path curvature and its decomposition into internal coordinate or curvilinear coordinate components. A first smaller charge transfer to the dienophile facilitates the rotation of gauche butadiene into its cis form. The actual chemical processes are initiated by a second larger charge transfer to the dienophile that facilitates pyramidalization of the reacting carbon centers, bond equalization, and biradicaloid formation of the reactants. The transition state is aromatically stabilized and moved by five path units into the entrance channel in line with the Hammond-Leffler postulate. The pseudorotation of the boat form into the halfchair of cyclohexene is analyzed. Predictions are made for the Diels-Alder reaction based on a 11-phase mechanism obtained by the URVA analysis.

  12. A computational study of vicinal fluorination in 2,3-difluorobutane: implications for conformational control in alkane chains.

    Science.gov (United States)

    Fox, Stephen J; Gourdain, Stephanie; Coulthurst, Anton; Fox, Clare; Kuprov, Ilya; Essex, Jonathan W; Skylaris, Chris-Kriton; Linclau, Bruno

    2015-01-19

    A comprehensive conformational analysis of both 2,3-difluorobutane diastereomers is presented based on density functional theory calculations in vacuum and in solution, as well as NMR experiments in solution. While for 1,2-difluoroethane the fluorine gauche effect is clearly the dominant effect determining its conformation, it was found that for 2,3-difluorobutane there is a complex interplay of several effects, which are of similar magnitude but often of opposite sign. As a result, unexpected deviations in dihedral angles, relative conformational energies and populations are observed which cannot be rationalised only by chemical intuition. Furthermore, it was found that it is important to consider the free energies of the various conformers, as these lead to qualitatively different results both in vacuum and in solvent, when compared to calculations based only on the electronic energies. In contrast to expectations, it was found that vicinal syn-difluoride introduction in the butane and by extension, longer hydrocarbon chains, is not expected to lead to an effective stabilisation of the linear conformation. Our findings have implications for the use of the vicinal difluoride motif for conformational control. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Organofluorine chemistry: synthesis and conformation of vicinal fluoromethylene motifs.

    Science.gov (United States)

    O'Hagan, David

    2012-04-20

    The C-F bond is the most polar bond in organic chemistry, and thus the bond has a relatively large dipole moment with a significant -ve charge density on the fluorine atom and correspondingly a +ve charge density on carbon. The electrostatic nature of the bond renders it the strongest one in organic chemistry. However, the fluorine atom itself is nonpolarizable, and thus, despite the charge localization on fluorine, it is a poor hydrogen-bonding acceptor. These properties of the C-F bond make it attractive in the design of nonviscous but polar organic compounds, with a polarity limited to influencing the intramolecular nature of the molecule and less so intermolecular interactions with the immediate environment. In this Perspective, the synthesis of aliphatic chains carrying multivicinal fluoromethylene motifs is described. It emerges that the dipoles of adjacent C-F bonds orientate relative to each other, and thus, individual diastereoisomers display different backbone carbon chain conformations. These conformational preferences recognize the influence of the well-known gauche effect associated with 1,2-difluoroethane but extend to considering 1,3-fluorine-fluorine dipolar repulsions. The synthesis of carbon chains carrying two, three, four, five, and six vicinal fluoromethylene motifs is described, with an emphasis on our own research contributions. These motifs obey almost predictable conformational behavior, and they emerge as candidates for inclusion in the design of performance organic molecules. © 2012 American Chemical Society

  14. Conformational kinetics of aliphatic tails

    Science.gov (United States)

    Ferrarini, Alberta; Moro, Giorgio; Nordio, Pier Luigi

    The master equation describing the random walk between sites identified with the stable conformers of a chain molecule, represents the extension to the time domain of the Rotational Isomeric State model. The asymptotic analysis of the multidimensional diffusion equation in the continuous torsional variables subjected to the configurational potential, provides a rigorous justification for the discrete models, and it supplies, without resorting to phenomenological parameters, molecular definitions of the kinetic rates for the conformational transitions occurring at each segment of the chain. The coupling between the torsional variables is fully taken into account, giving rise to cooperative effects. A complete calculation of the specific correlation functions which describe the time evolution of the angular functions probed by N.M.R. and dielectric relaxation measurements, has been performed for alkyl chains attached to a massive core. The resulting behaviour has been compared with the decay of trans and gauche populations of specific bonds, expressed in terms of suitable correlation functions whose time integrals lead quite naturally to the definition of effective kinetic constants for the conformational transitions.

  15. The effect of furazolidone on the physico-chemical properties of dimyristoylphosphatidylcholine bilayers: Relevance to anti-leishmanial therapy

    Science.gov (United States)

    Martins, Victor Hugo Giendruczak; Rodrigues, Marisa Raquel; Mascarenhas, Layoan Dantas; de Azambuja, Carla Roberta Lopes; Londoño, Julian Londoño; de Lima, Vânia Rodrigues

    2014-02-01

    In this study, the influence of furazolidone, an anti-leishmanial drug, on dimyristoylphosphatidylcholine (DMPC) liposome hydration degree, mobility and thermodynamics was investigated by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR) and differential scanning calorimetry (DSC). FTIR results showed that furazolidone was responsible for an increase in the hydrogen bound number and mobility of the lipid phosphate group. Furazolidone also affected the lipid choline group by increasing its motional freedom, as shown by FTIR and 1H NMR spin-lattice relaxation time measurements. At the DMPC interfacial region, FTIR results showed a drug-induced reduction of the carbonyl hydration and order degrees. Very weak interaction among furazolidone and the hydrophobic lipid chains was also observed. However, no furazolidone-induced changes on thermodynamical parameters, such as phase transition temperature (Tm) and enthalpy variation (ΔH), were detected by the DSC technique. Thus, furazolidone seems to interact preferentially with lipid polar and interfacial regions, enhancing the freedom for gauche-trans isomerization of the first methylene groups of DMPC acyl chains. Responses described in this paper may explain the improved activity of furazolidone-encapsulated liposomes by comparison with the effect of the free drug, described in literature. The findings can also improve further strategies for the potential therapeutic application of liposomal furazolidone as a drug delivery system and minimize the risk of drug resistance and collateral effects related to high toxicity.

  16. Approximate quantum chemical methods for modelling carbohydrate conformation and aromatic interactions: β-cyclodextrin and its adsorption on a single-layer graphene sheet.

    Science.gov (United States)

    Jaiyong, Panichakorn; Bryce, Richard A

    2017-06-14

    Noncovalent functionalization of graphene by carbohydrates such as β-cyclodextrin (βCD) has the potential to improve graphene dispersibility and its use in biomedical applications. Here we explore the ability of approximate quantum chemical methods to accurately model βCD conformation and its interaction with graphene. We find that DFTB3, SCC-DFTB and PM3CARB-1 methods provide the best agreement with density functional theory (DFT) in calculation of relative energetics of gas-phase βCD conformers; however, the remaining NDDO-based approaches we considered underestimate the stability of the trans,gauche vicinal diol conformation. This diol orientation, corresponding to a clockwise hydrogen bonding arrangement in the glucosyl residue of βCD, is present in the lowest energy βCD conformer. Consequently, for adsorption on graphene of clockwise or counterclockwise hydrogen bonded forms of βCD, calculated with respect to this unbound conformer, the DFTB3 method provides closer agreement with DFT values than PM7 and PM6-DH2 approaches. These findings suggest approximate quantum chemical methods as potentially useful tools to guide the design of carbohydrate-graphene interactions, but also highlights the specific challenge to NDDO-based methods in capturing the relative energetics of carbohydrate hydrogen bond networks.

  17. Tris{2-[(2-aminobenzylideneamino]ethyl}amine

    Directory of Open Access Journals (Sweden)

    Perla Elizondo Martínez

    2010-12-01

    Full Text Available The title Schiff base, C27H33N7, is a tripodal amine displaying C3 symmetry, with the central tertiary N atom lying on the threefold crystallographic axis. The N—CH2—CH2—N conformation of the pendant arms is gauche [torsion angle = 76.1 (3°], which results in a claw-like molecule, with the terminal aniline groups wrapped around the symmetry axis. The lone pair of the apical N atom is clearly oriented inwards towards the cavity, and should thus be chemically inactive. The amine NH2 substituents lie in the plane of the benzene ring to which they are bonded. With such an arrangement, one amine H atom forms an S(6 motif through a weak N—H...N hydrogen bond with the imine N atom, while the other is engaged in an intermolecular N—H...π contact involving the benzene ring of a neighbouring molecule related by inversion. The benzene rings also participate in an intramolecular C—H...π contact of similar strength. In the crystal structure, molecules are separated by empty voids (ca 5% of the crystal volume, although the crystal seems to be unsolvated.

  18. Parametrization of 2,2,2-trifluoroethanol based on the generalized AMBER force field provides realistic agreement between experimental and calculated properties of pure liquid as well as water-mixed solutions.

    Science.gov (United States)

    Vymětal, Jiří; Vondrášek, Jiří

    2014-09-04

    We present a novel force field model of 2,2,2-trifluoroethanol (TFE) based on the generalized AMBER force field. The model was exhaustively parametrized to reproduce liquid-state properties of pure TFE, namely, density, enthalpy of vaporization, self-diffusion coefficient, and population of trans and gauche conformers. The model predicts excellently other liquid-state properties such as shear viscosity, thermal expansion coefficient, and isotropic compressibility. The resulting model describes unexpectedly well the state equation of the liquid region in the range of 100 K and 10 MPa. More importantly, the proposed TFE model was optimized for use in combination with the TIP4P/Ew and TIP4P/2005 water models. It does not manifest excessive aggregation, which is known for other models, and therefore, it is supposed to more realistically describe the behavior of TFE/water mixtures. This was demonstrated by means of the Kirkwood-Buff theory of solutions and reasonable agreement with experimental data. We explored a considerable part of the parameter space and systematically tested individual combinations of parameters for performance in combination with the TIP4P/Ew and TIP4P/2005 water models. We observed ambiguity in parameters describing pure liquid TFE; however, most of them failed for TFE/water mixtures. We clearly demonstrated the necessity for balanced TFE-TFE, TFE-water, and water-water interactions which can be acquired only by employing implicit polarization correction in the course of parametrization.

  19. Exercices de vocabulaire en contexte niveau débutant

    CERN Document Server

    Eluerd, Roland

    2005-01-01

    Un entraînement à l'acquisition du lexique en contexte. Avec de nombreuses illustrations. Cet ouvrage s'adresse à des adolescents ou adultes débutants pour un travail en classe ou en autonomie. Un livre très simple à utiliser: 1 leçon = 1 thème = 1 double page - Un sommaire thématique en 50 leçons réparties selon 10 grands thèmes. Les 50 leçons suivent une progression méthodique de découverte et de pratique du vocabulaire conçue pour des lecteurs débutants (niveau A1 du cadre européen commun de référence). - Pour chaque leçon: > une présentation illustrée du vocabulaire, en contexte, en page de gauche; > des activités très simples (autonomie) en parge de droite. - Un index est proposé en fin d'ouvrage.

  20. Grammaire progressive du français corrigés : niveau intermédiaire : avec 680 exercices

    CERN Document Server

    Thiévenaz, Odile

    2013-01-01

    Les corrigés de la 3e édition de la Grammaire progressive du français - niveau intermédiaire Ce qui fait le succès de cette grammaire : Une organisation claire : la leçon de grammaire sur la page de gauche ; les exercices d'entraînement sur la page de droite ; 52 chapitres présentant les points généralement abordés aux niveaux A2 et B1 du Cadre européen commun de référence pour les langues ; Un apprentissage progressif : il suit la progression naturelle des méthodes de français ; Un usage souple : pour la classe ou en auto-apprentissage ; Une préparation adaptée aux certifications : un entraînement efficace pour mieux réussir aux examens ; Une large place faite à l'évaluation : de nombreux exercices de révision et des bilans réguliers. À découvrir dans cette troisième édition tout en couleurs (ISBN 978 209 038 124 5) : Un CD audio avec 14 documents sonores ; 80 nouveaux exercices et activités communicatives ; Des chapitres révisés et des exercices plus variés ; Un test d'�...

  1. Grammaire progressive du français niveau intermédiaire : avec 680 exercices

    CERN Document Server

    Grégoire, Maïa

    2013-01-01

    Une organisation claire : la leçon de grammaire sur la page de gauche ; les exercices d'entraînement sur la page de droite ; 52 chapitres présentant les points généralement abordés aux niveaux A2 et B1 du Cadre européen commun de référence pour les langues ; Un apprentissage progressif : il suit la progression naturelle des méthodes de français ; Un usage souple : pour la classe ou en auto-apprentissage ; Une préparation adaptée aux certifications : un entraînement efficace pour mieux réussir aux examens ; Une large place faite à l'évaluation : de nombreux exercices de révision et des bilans réguliers. À découvrir dans cette troisième édition tout en couleurs : Un CD audio avec 14 documents sonores ; 80 nouveaux exercices et activités communicatives ; Des chapitres révisés et des exercices plus variés ; Un test d'évaluation avec ses corrigés ; Et... un livre web, 100% en ligne, inclus. Cet ouvrage contient un code d'activation donnant gratuitement accès sur http://livre-web.com...

  2. 2H{ 19F} REDOR for distance measurements in biological solids using a double resonance spectrometer

    Science.gov (United States)

    Grage, Stephan L.; Watts, Jude A.; Watts, Anthony

    2004-01-01

    A new approach for distance measurements in biological solids employing 2H{ 19F} rotational echo double resonance was developed and validated on 2H, 19F- D-alanine and an imidazopyridine based inhibitor of the gastric H +/K +-ATPase. The 2H- 19F double resonance experiments presented here were performed without 1H decoupling using a double resonance NMR spectrometer. In this way, it was possible to benefit from the relatively longer distance range of fluorine without the need of specialized fluorine equipment. A distance of 2.5 ± 0.3 Å was measured in the alanine derivative, indicating a gauche conformation of the two labels. In the case of the imidazopyridine compound a lower distance limit of 5.2 Å was determined and is in agreement with an extended conformation of the inhibitor. Several REDOR variants were compared, and their advantages and limitations discussed. Composite fluorine dephasing pulses were found to enhance the frequency bandwidth significantly, and to reduce the dependence of the performance of the experiment on the exact choice of the transmitter frequency.

  3. McCarthyism and American Opera L’Opéra américain face au McCarthyisme

    Directory of Open Access Journals (Sweden)

    Klaus-Dieter Gross

    2009-11-01

    Full Text Available L’atmosphère anti-communiste qui caractérisa les États-Unis entre la fin de la seconde Guerre Mondiale et la fin des années 1950, et qui culmina avec des mesures légales ou extra-légales prises par le Comité des Activités Anti-américaines et par le sénateur McCarthy, eut une influence décisive sur l’opéra américain. Quelques rares ouvrages manifestent un soutien diffus pour le McCarthyisme (Still et Nabobov, tandis que d’autres nient son impact en promouvant des idées de gauche (Robinson et Blitzstein. D’autres œuvres incorporent la peur de la vague rouge dans leurs thèmes, mais sans lui donner une importance autre que secondaire. Enfin, trois opéras (Bernstein, Floyd et Ward abordent frontalement la question du fonctionnement rituel et des méthodes liberticides du McCarthyisme. Le déclin de ce mouvement coïncida, vers le début des années 1960, avec l’émergence d’un style opératique moins traditionaliste et plus abstrait.

  4. Molecular dynamics simulations of polyethers and a quaternary ammonium ionic liquid as CO2 absorbers

    Science.gov (United States)

    Cardoso, Piercarlo Fortunato; Fernandez, Juan S. L. C.; Lepre, Luiz Fernando; Ando, Rômulo Augusto; Costa Gomes, Margarida F.; Siqueira, Leonardo J. A.

    2018-04-01

    The properties of mixtures of butyltrimethylammonium bis(trifluoromethylsulfonyl)imide, [N4111][NTf2], with poly(ethyleneglycol) dimethyl ether, PEO, were described as a function of PEO chain size by molecular dynamics simulations. Both PEO chain size and mixture composition revealed to play a significant role in determining the structure and the dynamics of the fluids. The remarkably higher viscosity observed for mixtures composed by 0.25 mole fraction of PEO was attributed to the increase in the gauche population of OCCO dihedral of the polyether of longer chains. The negative solvation enthalpy (ΔsolH < 0) and entropy (ΔsolS < 0) revealed a favorable CO2 absorption by the neat and mixture systems. The CO2 absorption was higher in neat PEO, particularly considering longer chains. The gas solubility in the mixtures presented intermediate values in comparison to the neat PEO and neat ionic liquid. The CO2 solutions had their structures discussed in the light of the calculated radial and spatial distribution functions.

  5. Mercury coordination polymers with flexible ethane-1,2-diyl-bis-(pyridyl-3-carboxylate): Synthesis, structures, thermal and luminescent properties

    Energy Technology Data Exchange (ETDEWEB)

    Vallejos, Javier [Departamento de Química, Universidad Católica del Norte, Av. Angamos 0610, Antofagasta (Chile); Brito, Iván, E-mail: ivanbritob@yahoo.com [Departamento de Quimica, Universidad de Antofagasta, Av. Angamos 601, Antofagasta (Chile); Cárdenas, Alejandro [Departamento de Física, Universidad de Antofagasta, Av. Angamos 601, Antofagasta (Chile); Llanos, Jaime [Departamento de Química, Universidad Católica del Norte, Av. Angamos 0610, Antofagasta (Chile); Bolte, Michael [Institut für Anorganische Chemie der Goethe—Universität Frankfurt, Max-von-Laue-Strasse 7, D-60438 Frankfurt am Main (Germany); López-Rodríguez, Matías [Instituto de Bio-Orgánica “Antonio González”, Universidad de La Laguna, Astrofísico Francisco Sánchez N° 2, La Laguna, Tenerife (Spain)

    2015-03-15

    The reaction of the flexible ligand, ethane-1,2-diyl-bis-(pyridyl-3-carboxylate), (L) with HgI{sub 2} and HgBr{sub 2} salts under the same experimental conditions leads to the formation of two coordination polymers with different motifs: ([Hg(L)(Br{sub 2})]){sub n}(1) and ([Hg(L)(I{sub 2})]){sub n}(2). In both compounds, the ligand, (L) acts in a μ2-N:N′-bidentate fashion to link HgBr{sub 2} and HgI{sub 2} units to form a linear and helical chain motif, along [1 0 0] for (1) and [0 0 1] for (2). The ethylene moiety of (L) has gauche and trans conformation in compounds (1) and (2), respectively. The flexible conformation of L produces differences in the optical and crystal properties of the two compounds. - Graphical abstract: This work demonstrates how the HgX{sub 2} units are coordinates by bi-dentate ligand forming polymeric coordination complexes by self-assembly of both chemical units.- Highlights: • News 1-D d{sup 10} transition metal coordination polymers. • The photoluminescent properties have been measured. • The thermal properties have been measured.

  6. N-Benzoyl-2-nitrobenzenesulfonamide

    Directory of Open Access Journals (Sweden)

    P. A. Suchetan

    2012-02-01

    Full Text Available In the title compound, C13H10N2O5S, the N—C bond in the C—SO2—NH—C segment has gauche torsion angles with respect to the S=O bonds. The conformation between the N—H bond and the ortho-nitro group in the sulfonyl benzene ring is syn. The molecule is twisted at the S—N bond with a torsion angle of −63.4 (2°. The sulfonyl benzene ring is tilted by 77.1 (1° relative to the —SO2—NH—C—O segment. The dihedral angle between the sulfonyl and the benzoyl benzene rings is 88.6 (1°. In the crystal, pairs of N—H...O(S hydrogen bonds link the molecules into inversion dimers, which are linked by weak C—H...O and C—H...π interactions along the b axis.

  7. Structural effects on the chemical shift of exo - endo and exo - exo tetra cyclo dodecane; Efeitos estruturais sobre o deslocamento quimico de exo-endo e exo-exo tetraciclododecanos

    Energy Technology Data Exchange (ETDEWEB)

    Leal, Katia Zaccur [Universidade Federal Fluminense, Niteroi, RJ (Brazil). Dept. de Fisico-Quimica; Costa, Valentim E.U. [Rio Grande do Sul Univ., Porto Alegre, RS (Brazil). Dept. de Quimica Organica; Seidl, Peter Rudolf [Instituto Militar de Engenharia (IME), Rio de Janeiro, RJ (Brazil). Secao de Quimica

    1992-12-31

    The systematic investigation of rigid cyclic molecules has provided a basis for a number of concepts presently employed in NMR spectroscopy. Bicyclic systems of norbornyl family have been extensively studied in this respect but their tetracyclic analogs have received much less attention. The large number of peaks that into narrow chemical shift ranges and the presence of intramolecular affects that arise from groups brought into close proximity have probably been responsible for this state of affairs. As in the case of other polycyclic rings of interest, more data from model systems would be desirable. We have analysed the proton and carbon-13 spectra of endo-endo tetra cyclo [6.1.1{sup 3,6}.0{sup 2,7}] dodeca-4-en-10-ol (1A) and its analogs and found interactions between atoms that are four or more bonds away. Although these upfield {delta} and {delta}{sub E} effects could be accounted for by invoking steric interactions similar to those that give to the well-know {gamma}gauche effect, there are other discrepancies between carbon-13 chemical shifts of tetracyclic dodecanes and their bicyclic analogs that are not amenable to simple rationalizations and a look other situations where such effects may be present would be recommendable. (author) 19 refs., 8 figs., 8 tabs.

  8. Pourquoi les filles sont si bonnes en maths et 40 autres histoires sur le cerveau de l’homme

    CERN Document Server

    Cohen, Laurent

    2012-01-01

    Pourquoi les filles sont-elles si bonnes en maths ? Pourquoi n'avons-nous aucun souvenir avant l'âge de 2 ans ? Pourquoi le fait d'avoir deux yeux nous aide-t-il à voir en trois dimensions ? En quoi la pratique des jeux vidéo aide-t-elle à devenir pilote d'avion ? Pourquoi se lave-t-on les mains quand on a honte ? Le cerveau d'un homme de droite est-il différent de celui d'un homme de gauche ? Et que fait notre cerveau quand nous ne faisons rien ? Laurent Cohen répond ici à toutes ces questions avec la clarté et le brio qu'on lui connaît, sans oublier l'humour ni négliger les dernières avancées scientifiques. ?Laurent Cohen est professeur de neurologie à l'hôpital de la Pitié-Salpêtrière- Paris-VI. Il a notamment publié L'Homme thermomètre et Pourquoi les chimpanzés ne parlent pas, qui ont été de grands succès.

  9. Synthesis and characterization of two new zinc(II) coordination polymers with bidentate flexible ligands: Formation of a 2D structure with (44.62)-sql topology

    Science.gov (United States)

    Lalegani, Arash; Khaledi Sardashti, Mohammad; Gajda, Roman; Woźniak, Krzysztof

    2017-12-01

    Zinc(II) coordination polymers [Zn(bip)2(NCS)2]n (1) and [Zn(μ-bbd)(N3)2]n (2) were synthesized by using the neutral flexible bidentate N-donor ligands 1,4-bis(3,5-dimethylpyrazolyl)butane (bbd) and 1,3-bis(imidazolyl)propane (bip), mono-anionic NCS- or N3-ligand and zinc(II) chloride salts. The results of the X-ray analyses demonstrate that in the structure of 1, the zinc(II) ion is located on an inversion center and exhibits an ZnN6 octahedral arrangement while, in the structure of 2, the zinc(II) ion adopts an ZnN4 tetrahedral geometry. In the polymer 1, the NCS groups are terminally N-bonded to the metal center and the each bip with anti-gauche conformation acts as bridging connecting four zinc(II) ions to form a two-dimensional network with a sql [point symbol (44.62)] topology while, in the polymer 1, the N3 groups are terminally bonded to the metal center and each bbd with anti-anti-anti conformation acts as bridging ligand connecting two zinc(II) ions to form a one-dimensional zig-zag chain. Coordination compounds 1 and 2 have been characterized by infrared spectroscopy, elemental analyses and single-crystal X-ray diffraction. Thermal analyses of polymers were also presented.

  10. The Cambrian cavalcades in the Cuchilla Dionisio sub ground. Uruguay

    International Nuclear Information System (INIS)

    Bossi, J.

    2010-01-01

    Most tratadistes consider that Sierra Ballena shear zone (SBSZ) is the western limit of an all octon block after the paper of Boss i and Gauche r (2004) showing a detailed geological map. The same method was applied to sporulation block in the Ne of Treinta y Tres city. It was obtained a 1/100.000 geological map with photo geology and 140 field data in an area of 3500 k m2. This document allowed to discover two kinds of mega - faults put in action at the same time (about 525 Ma): a mega shear zone N30E80E with proto - to ultramylonites similar to SBSZ and a regional thrust fault with vergence to NNW. The thrust fault has different features according to the affected type of rocks. At La Micaela, the mica schists are thrust ed by gneisses and migmatites. To the N W the gneisses became firstly sharply laminated and then, horizontal ultramylonites. Both kind of faulting produced at the same time may not be explained by an orthogonal collision and instead of it, is a naturalist proof of tangential collision and alcoholisation nature of the crustal block. In order to easily understand the new proposal it is necessary to change Paso del Dragón fm by Micaela fm, Cuchilla Dionisio Terrane by Treinta y Tres; Punta del Este Terrane by Punta del Este sub - terrane

  11. Conformational impact of structural modifications in 2-fluorocyclohexanone

    Directory of Open Access Journals (Sweden)

    Francisco A. Martins

    2017-08-01

    Full Text Available 2-Haloketones are building blocks that combine physical, chemical and biological features of materials and bioactive compounds, while organic fluorine plays a fundamental role in the design of performance organic molecules. Since these features are dependent on the three-dimensional chemical structure of a molecule, simple structural modifications can affect its conformational stability and, consequently, the corresponding physicochemical/biological property of interest. In this work, structural changes in 2-fluorocyclohexanone were theoretically studied with the aim at finding intramolecular interactions that induce the conformational equilibrium towards the axial or equatorial conformer. The interactions evaluated were hydrogen bonding, hyperconjugation, electrostatic and steric effects. While the gauche effect, originated from hyperconjugative interactions, does not appear to cause some preferences for the axial conformation of organofluorine heterocycles, more classical effects indeed rule the conformational equilibrium of the compounds. Spectroscopic parameters (NMR chemical shifts and coupling constants, which can be useful to determine the stereochemistry and the interactions operating in the series of 2-fluorocyclohexanone derivatives, were also calculated.

  12. Physicochemical interactions among α-eleostearic acid-loaded liposomes applied to the development of drug delivery systems

    Science.gov (United States)

    Nogueira, Alessandro Oliveira de Moraes; de Sousa, Robson Simplício; Pereira, Luiza Silveira; Mallmann, Christian; da Silva Ferreira, Ailton; Clementin, Rosilene Maria; de Lima, Vânia Rodrigues

    2018-02-01

    In this study, α-eleostearic acid-loaded (α-ESA-loaded) dimyristoylphosphatidylcholine (DMPC) liposomes had their physicochemical properties characterized by horizontal attenuated total reflectance Fourier transform infrared (HATR-FTIR) spectroscopy, nuclear magnetic resonance (NMR) and differential scanning calorimetry (DSC). In vitro thiobarbituric acid reactive substance (TBARS) assays were performed to obtain preliminary information on the oxidative potential of the system. An α-ESA-promoted ordering effect in the lipid phosphate region was observed. It was associated with a rotation restriction due to an increase in the amount of lipid group hydrogen bonds. The fatty acid was responsible for the reduction in the degree of hydration of carbonyl groups located in the interfacial region of lipids. α-ESA disordered the DMPC methylene acyl chains by trans-gauche isomerization and increased its rotation rate. TBARS results showed pro-oxidant behavior on liposomes, induced by α-ESA. The discussion about the responses considered the degree of saturation of phosphatidylcholines and suggested that the α-ESA oxidative effects may be modulated by the liposome lipid composition. The versatility of liposomal carriers may be promising for the development of efficacious α-ESA-based drug delivery systems. Results described in this study contribute to the selection of adequate material to produce them.

  13. El Gran Proyecto Urbano ”Paris Rive Gauche”: La transformación de un baldío ferroviario-industrial en un nuevo barrio parisino / The Great Urban Project

    Directory of Open Access Journals (Sweden)

    Duval-Zack, Chloé

    2006-11-01

    Full Text Available “Paris Rive Gauche” es el proyecto urbano más importante que conoció la ciudad desde la remodelación de Haussmann. El perímetro de intervención, de aproximadamente unas 130 hectáreas de terrenos baldíos de origen ferroviario-industriales, se localiza intramuros a lo largo del Sena y del tejido urbano del distrito 13. Para concretar su política urbana y crear un nuevo barrio, el Municipio, junto con la SEMAPA, formalizó un programa ambicioso de revitalización, mediante la mezcla de funciones urbanas y la construcción de la Biblioteca Nacional de Francia como proyecto detonante./"Paris Rive Gauche" is the most important urban project in Paris since the Haussmann's remodelling. The area of intervention, approximately 130 hectares of railways and abandoned industries, is located intra-muros (within the walls along the Seine and the 13th district. To translate the urban politics and to create a new neighborhood, the City, together with the SEMAPA, formalized an ambitious program of revitalisation, with the mixture of urban functions and the construction of the National Library of France as a trigger project.

  14. Three-dimensional structural analysis of the group B polysaccharide of Neisseria meningitidis 6275 by two-dimensional NMR: The polysaccharide is suggested to exist in helical conformations in solution

    Energy Technology Data Exchange (ETDEWEB)

    Yamasaki, Ryohei; Bacon, B. (Univ. of California, San Francisco (USA) Veterans Administration Medical Center, San Francisco, CA (USA))

    1991-01-22

    The solution conformations of the group B polysaccharide of Neisseria meningitidis were analyzed by DQF-COSY and pure absorption 2D NOE NMR with three mixing times. The pyranose ring of the sialic acid residue was found to be in the {sup 2}C{sub 5} conformation. The DQF-COSY analysis indicated that the orientations of H6 and H7 and of H7 and H8 are both gauche. In order to overcome the difficulties in analyzing the NOE data due to the two sets of proton overlaps, molecular modeling of {alpha}-2,8-linked sialic acid oligomers was carried out to investigate possible conformers, and theoretical NOE calculations were performed by using CORMA (complete relaxation matrix analysis). The analysis suggests that the polysaccharide adopts helical structures for which the {phi} (defined by O6-C2-O8-C8) and {psi} (C2-O8-C8-C7) angles are in the following ranges: {phi}-60 to 0{degree}, {psi} 115-175{degree} or {phi} 90-120{degree}, {psi}55-175{degree}. The weak affinity of anti-B antibodies for smaller {alpha}-2,8-linked oligosaccharides may be due to the fact that such oligomers are more flexible and may not form an ordered structure as the poly(sialic acid) does.

  15. ALICE presents its first award to Industry

    CERN Multimedia

    On 19 June, a French company received the first ALICE award to industry. ST Technologies has provided ALICE with a key device for the design of a very sophisticated chip for the readout of the ALICE Time Projection Chamber. Behind from left to right (Derrière de gauche à droite): Bernardo Mota, member of the ALTRO design team, Jurgen Schukraft, ALICE Spokesperson, Luciano Musa, leader of the ALTRO Design Team and Coordinator of the ALICE TPC FEE, Roberto Camapagnolo, member of the ALICE TPC FEE team, Jean-Pierre Coffin, Deputy of the ALICE Collaboration Board Chairman, Hans de Groot ALICE Resource Coordinator, Laurent Degoujon, ST - Data Converter Design Manager, Claude Engster, member of the ALICE TPC FEE team, Alain Delpi, ST - Data Converter Business Unit Manager, Carmen Gonzalez, member of the ALICE TPC FEE team, Yiota Foka, ALICE Outreach Coordinator; Front: Fabio Formenti , EP-ED Group Leader, Juan Antonio Rubio, ETT Division Leader The ALICE experiment is setting new demands on readout electronics i...

  16. Le corps, instrument de connaissance du monde: la connaissance des Anciens Toltèques

    Directory of Open Access Journals (Sweden)

    Mabel Franzone

    2009-10-01

    Full Text Available Cet article traite le corps comme instrument de la connaissance de l’univers. Le corps s’étend vers des contrées infinies, se prolonge, atteint d’autres règnes, cherche l’unité absolue de ce qu’on appelle l’intention. L’intention est le mot clé pour les Anciens Toltèques, réunissant sous ce mot le visible et l’invisible, la volonté de la Nature et celle de l’univers. Le corps n’est qu’un instrument et pour arriver à le parfaire devons chercher la totalité de nous-mêmes, réussir la communication de deux côtés, droit et gauche, aller à la quête d’autres expériences, inimaginables. Les conditions nécessaires sont d’avoir un corps puissant et d’emmagasiner de l’énergie. Tout l’enseignement des sorciers est fondé dans un vrai changement de conception du monde et de la perception de ce monde. L’objectif final est celui de pouvoir choisir sa propre mort ; la vraie, la seule, l’unique liberté de l’homme.

  17. La Revolución francesa en marcha: storytelling en la campaña de Mélenchon para las elecciones presidenciales

    Directory of Open Access Journals (Sweden)

    Eug\\u00E9nie Richard

    2013-01-01

    Full Text Available El artículo analiza la utilización del storytelling por los cuatro principales candida- tos a la elección presidencial francesa de 2012. Entre ellos se destaca Jean-Luc Mélenchon, candidato del Front de Gauche, que supo apli- car en su campaña estrategias de storyline, de framing y de networking. El candidato revivió el ideal de la Revolución francesa invitando al electorado a unos actos simbólicos de partici- pación política y utilizando el contexto inter- nacional de crisis para posicionar un discurso de “indignado”. A pesar de su semifracaso en las urnas, su campaña fue la más innovadora y dio a conocer nuevas formas de comunicación y de participación en este país poco acostum- brado al uso del storytelling en campaña.

  18. Synthesis and conformational analysis of hybrid α/β-dipeptides incorporating S-glycosyl-β(2,2)-amino acids.

    Science.gov (United States)

    García-González, Iván; Mata, Lara; Corzana, Francisco; Jiménez-Osés, Gonzalo; Avenoza, Alberto; Busto, Jesús H; Peregrina, Jesús M

    2015-01-12

    We synthesized and carried out the conformational analysis of several hybrid dipeptides consisting of an α-amino acid attached to a quaternary glyco-β-amino acid. In particular, we combined a S-glycosylated β(2,2)-amino acid and two different types of α-amino acid, namely, aliphatic (alanine) and aromatic (phenylalanine and tryptophan) in the sequence of hybrid α/β-dipeptides. The key step in the synthesis involved the ring-opening reaction of a chiral cyclic sulfamidate, inserted in the peptidic sequence, with a sulfur-containing nucleophile by using 1-thio-β-D-glucopyranose derivatives. This reaction of glycosylation occurred with inversion of configuration at the quaternary center. The conformational behavior in aqueous solution of the peptide backbone and the glycosidic linkage for all synthesized hybrid glycopeptides was analyzed by using a protocol that combined NMR experiments and molecular dynamics with time-averaged restraints (MD-tar). Interestingly, the presence of the sulfur heteroatom at the quaternary center of the β-amino acid induced θ torsional angles close to 180° (anti). Notably, this value changed to 60° (gauche) when the peptidic sequence displayed aromatic α-amino acids due to the presence of CH-π interactions between the phenyl or indole ring and the methyl groups of the β-amino acid unit. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Development of synchrotron DSC/WAXD/SAXS simultaneous measurement system for polymeric materials at the BL40B2 in SPring-8 and its application to the study of crystal phase transitions of fluorine polymers

    International Nuclear Information System (INIS)

    Masunaga, Hiroyasu; Sasaki, Sono; Takata, Masaki; Inoue, Katsuaki; Ohta, Noboru; Yagi, Naoto; Tashiro, Kohji; Hanesaka, Makoto

    2007-01-01

    A new system of rapidly-scanning DSC/WAXD/SAXS simultaneous measurements has been successfully developed at the BL40B2 in SPring-8, Japan. The combination of the ultra-bright and highly-directional X-ray beams with the highly-sensitive two-dimensional (2D) detectors such as an imaging plate (IP), a CCD detector and a flat panel (FP) detector has made it possible to perform the rapidly-scanning time-resolved measurements of WAXD and SAXS for the polymeric materials subjected to the various kinds of external field like temperature, tensile force, magnetic field, hydrostatic pressure, and so on. The experimental data about the phase transitions of vinylidene fluoride-trifluoroethylene copolymer with VDF 82 mol% content and poly(vinylidene fluoride) form I have been presented as actual examples, where the phase transitions of the polar crystal consisting of planar-zigzag chains to the gauche-type high-temperature phase have been confirmed definitely and the remarkable change in lamellar stacking structure could be detected in the temperature region immediately below the melting point. (author)

  20. Sum frequency generation (SFG) vibrational spectroscopy of planar phosphatidylethanolamine hybrid bilayer membranes under water.

    Science.gov (United States)

    Kett, Peter J N; Casford, Michael T L; Davies, Paul B

    2010-06-15

    Sum frequency generation (SFG) spectroscopy has been used to study the structure of phosphatidylethanolamine hybrid bilayer membranes (HBMs) under water at ambient temperatures. The HBMs were formed using a modified Langmuir-Schaefer technique and consisted of a layer of dipalmitoyl phosphatidylethanolamine (DPPE) physisorbed onto an octadecanethiol (ODT) self-assembled monolayer (SAM) at a series of surface pressures from 1 to 40 mN m(-1). The DPPE and ODT were selectively deuterated so that the contributions to the SFG spectra from the two layers could be determined separately. SFG spectra in both the C-H and C-D stretching regions confirmed that a monolayer of DPPE had been adsorbed to the ODT SAM and that there were gauche defects within the alkyl chains of the phospholipid. On adsorption of a layer of DPPE, methylene modes from the ODT SAM were detected, indicating that the phospholipid had partially disordered the alkanethiol monolayer. SFG spectra recorded in air indicated that removal of water from the surface of the HBM resulted in disruption of the DPPE layer and the formation of phospholipid bilayers.

  1. Conditional solvation thermodynamics of isoleucine in model peptides and the limitations of the group-transfer model.

    Science.gov (United States)

    Tomar, Dheeraj S; Weber, Valéry; Pettitt, B Montgomery; Asthagiri, D

    2014-04-17

    The hydration thermodynamics of the amino acid X relative to the reference G (glycine) or the hydration thermodynamics of a small-molecule analog of the side chain of X is often used to model the contribution of X to protein stability and solution thermodynamics. We consider the reasons for successes and limitations of this approach by calculating and comparing the conditional excess free energy, enthalpy, and entropy of hydration of the isoleucine side chain in zwitterionic isoleucine, in extended penta-peptides, and in helical deca-peptides. Butane in gauche conformation serves as a small-molecule analog for the isoleucine side chain. Parsing the hydrophobic and hydrophilic contributions to hydration for the side chain shows that both of these aspects of hydration are context-sensitive. Furthermore, analyzing the solute-solvent interaction contribution to the conditional excess enthalpy of the side chain shows that what is nominally considered a property of the side chain includes entirely nonobvious contributions of the background. The context-sensitivity of hydrophobic and hydrophilic hydration and the conflation of background contributions with energetics attributed to the side chain limit the ability of a single scaling factor, such as the fractional solvent exposure of the group in the protein, to map the component energetic contributions of the model-compound data to their value in the protein. But ignoring the origin of cancellations in the underlying components the group-transfer model may appear to provide a reasonable estimate of the free energy for a given error tolerance.

  2. Halocarbons as hydrogen bond acceptors: a spectroscopic study of haloethylbenzenes (PhCH2CH2X, X = F, Cl, Br) and their hydrate clusters.

    Science.gov (United States)

    Robertson, Patrick A; Villani, Luigi; Dissanayake, Uresha L M; Duncan, Luke F; Abbott, Belinda M; Wilson, David J D; Robertson, Evan G

    2018-03-28

    The electronic spectra of 2-bromoethylbenzene and its chloro and fluoro analogues have been recorded by resonant two-photon ionisation (R2PI) spectroscopy. Anti and gauche conformers have been assigned by rotational band contour analysis and IR-UV ion depletion spectroscopy in the CH region. Hydrate clusters of the anti conformers have also been observed, allowing the role of halocarbons as hydrogen bond acceptors to be examined in this context. The donor OH stretch of water bound to chlorine is red-shifted by 36 cm -1 , or 39 cm -1 in the case of bromine. Although classed as weak H-bond acceptors, halocarbons are favourable acceptor sites compared to π systems. Fluorine stands out as the weakest H-bond acceptor amongst the halogens. Chlorine and bromine are also weak H-bond acceptors, but allow for more geometric lability, facilitating complimentary secondary interactions within the host molecule. Ab initio and DFT quantum chemical calculations, both harmonic and anharmonic, aid the structural assignments and analysis.

  3. Cine Qua Non: The Political Import and Impact of The Battle of Algiers Cine Qua Non : L’impact de La bataille d’Alger

    Directory of Open Access Journals (Sweden)

    Stephen J. Whitfield

    2012-03-01

    Full Text Available Co-production italo-algérienne (en français et en arabe, La Battaglia di Algeri (1965, mérite le titre de meilleur film jamais réalisé. Gillo Pontecorvo, réalisateur et co-scénariste, montre avec brio et perspicacité les luttes de groupes d’insurgés se livrant à une guérilla urbaine dans l’Alger des années 1954-1957. Dans son portrait des exactions terroristes, ce film anticipe une vision du monde actuel, empli d’une violence effroyable, insoutenable. Ce film prémonitoire a un impact indéniable sur le temps présent. Que l’on soit de gauche ou de droite, de 1965 à nos jours, ce film ne cesse de fasciner. Ainsi dans le cadre de cette étude, je tenterai de mettre en relief la réalité historique à travers l’art cinématographique. Censuré en France en 1965, et peu projeté en salle dans la décennie qui suivit, ce film garde de sa force impressionnante grâce à son style étonnant mais aussi au thème choisi, criant par son éternelle actualité.

  4. Pressure-dependent {sup 13}C chemical shifts in proteins: origins and applications

    Energy Technology Data Exchange (ETDEWEB)

    Wilton, David J. [University of Sheffield, Department of Molecular Biology and Biotechnology (United Kingdom); Kitahara, Ryo [Ritsumeikan University, College of Pharmaceutical Sciences (Japan); Akasaka, Kazuyuki [Kinki University, Department of Biotechnological Science, School of Biology-Oriented Science and Technology (Japan); Williamson, Mike P. [University of Sheffield, Department of Molecular Biology and Biotechnology (United Kingdom)], E-mail: m.williamson@sheffield.ac.uk

    2009-05-15

    Pressure-dependent {sup 13}C chemical shifts have been measured for aliphatic carbons in barnase and Protein G. Up to 200 MPa (2 kbar), most shift changes are linear, demonstrating pressure-independent compressibilities. CH{sub 3}, CH{sub 2} and CH carbon shifts change on average by +0.23, -0.09 and -0.18 ppm, respectively, due to a combination of bond shortening and changes in bond angles, the latter matching one explanation for the {gamma}-gauche effect. In addition, there is a residue-specific component, arising from both local compression and conformational change. To assess the relative magnitudes of these effects, residue-specific shift changes for protein G were converted into structural restraints and used to calculate the change in structure with pressure, using a genetic algorithm to convert shift changes into dihedral angle restraints. The results demonstrate that residual {sup 13}C{alpha} shifts are dominated by dihedral angle changes and can be used to calculate structural change, whereas {sup 13}C{beta} shifts retain significant dependence on local compression, making them less useful as structural restraints.

  5. Excitons in conjugated polymers: Do we need a paradigma change?

    Energy Technology Data Exchange (ETDEWEB)

    Beenken, Wichard J.D. [Department of Theoretical Physics I, Ilmenau University of Thechnology (Germany)

    2009-12-15

    We have previously shown that both, polymer conformation and dynamics are crucial for the exciton transport in conjugated polymers. Thereby we found that the usual Foerster-type hopping transfer model - even if one applies the line-dipole approximation - falls short in one crucial aspect: the nature of the sites the excitons are transferred between is still unclear. We found that the simple model of spectroscopic units defined as segments of the polymer chains separated by structural defects breaking the {pi}-conjugation is only justified for chemical defects like hydrogenated double bonds, or extreme gauche (90 ) torsions between the monomers. Both defects are far too rare in a well-prepared conjugated polymer to explain the mean spectroscopic-unit length of typically 6-7 monomers. Meanwhile, also the concept of dynamical formation of the spectroscopic units, we had previously suggested, has also failed. Thus the question of a paradigma change concerning the exciton transport in conjugated polymers appears on the agenda. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  6. Partidos e trabalhadores na transição democrática: a luta pela hegemonia na esquerda brasileira

    Directory of Open Access Journals (Sweden)

    Marco Aurélio Santana

    2012-01-01

    Full Text Available Cet article analyse les arguments invoqués lors du processus de dispute hégémonique qui eut lieu au sein de la gauche brésilienne au cours des années 1970-1980. L'analyse met l'accent sur la manière dont le Parti Communiste Brésilien (PCB a traité l'avènement du Parti des Travailleurs (PT et aussi comment le PT a fait face à cette dispute qui l'opposa au PCB. On pourra ainsi percevoir la vision que chaque parti avait de lui-même ainsi que de son opposant. Tout au long de l'analyse, l'article décrit aussi le scénario concret au sein duquel les deux partis agissaient. Ce travail a pour base des recherches, des sources secondaires, ainsi que la documentation officielle produite par les militants des deux partis et les prises de positions affichées dans leurs organes de presse respectifs.

  7. Crystal structure of cis-anti-cis-dicyclohexane-18-crown-6 acetonitrile disolvate

    Directory of Open Access Journals (Sweden)

    Alexander Nazarenko

    2015-07-01

    Full Text Available The title compound (systematic name: cis-anti-cis-2,5,8,15,18,21-hexaoxatricyclo[20.4.0.09,14]hexacosane acetonitrile disolvate, C20H36O6·2CH3CN, crystallizes from an acetonitrile solution of dicyclohexane-18-crown-6 on evaporation. The molecule is arranged around a center of symmetry with half the crown ether molecule and one molecule of acetonitrile symmetry independent. All O—C—C—O torsion angles are gauche while all C—O—C—C angles are trans. The sequence of torsion angles is [(tg+t(tg−t]3; the geometry of oxygen atoms is close to pseudo-D3d with three atoms below and three atoms above the mean plane, with an average deviation of ±0.16 (1 Å from the mean plane. This geometry is identical to that observed in metal ion complexes of dicyclohexane-18-crown-6 but differs significantly from the conformation of a free unsolvated molecule. Each acetonitrile molecule connects to a crown ether molecule via two of its methyl group H atoms (C—H...O. Weaker interactions exist between the third H atom of the acetonitrile methyl group and an O atom of a neighbouring crown ether molecule (C—H...O; and between the N atom of the acetonitrile molecule and a H atom of another neighbouring crown ether molecule. All these intermolecular interactions create a three-dimensional network stabilizing the disolvate.

  8. A study of van der Waals complexes of 1,2-dichloroethane in paraffin oil by FTIR spectroscopy and ab initio calculations.

    Science.gov (United States)

    Fishman, A I; Noskov, A I; Aminova, R M; Skochilov, R A

    2015-02-05

    Weak molecular interactions of 1,2-dichloroethane dissolved in paraffin oil were investigated by FTIR spectroscopy. Occurrence of isosbestic points in the spectra along with the factor analysis showed that DCE⋯DCE dimers are formed in solutions at DCE concentrations between 7 and 15 vol.%. It was found that both trans and gauche conformers are involved in the complexation, forming a tg-dimer. From the spectra collected at 200-222 K, the complexation enthalpy was determined: -4.2±0.4 kcal mol(-1). The equilibrium geometry of tg-dimer and the vibrational frequencies were determined from the density functional calculations performed at B3LYP/6-311++G(d,p) and 6-31G(d,p) levels. The C-C bonds of the two molecules involved in tg-dimers were found to be oriented nearly perpendicular to each other. The complexation energy calculated using 6-31G(d,p) and 6-311++G(d,p) basis sets was found to be -1.59 and -1.52 kcal mol(-1), respectively. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. The first 3':5'-cyclic nucleotide-amino acid complex: L-His-cIMP.

    Science.gov (United States)

    Slepokura, Katarzyna

    2012-08-01

    In the crystal structure of the L-His-cIMP complex, i.e. L-histidinium inosine 3':5'-cyclic phosphate [systematic name: 5-(2-amino-2-carboxyethyl)-1H-imidazol-3-ium 7-hydroxy-2-oxo-6-(6-oxo-6,9-dihydro-1H-purin-9-yl)-4a,6,7,7a-tetrahydro-4H-1,3,5,2λ(5)-furo[3,2-d][1,3,2λ(5)]dioxaphosphinin-2-olate], C(6)H(10)N(3)O(2)(+)·C(10)H(10)N(4)O(7)P(-), the Hoogsteen edge of the hypoxanthine (Hyp) base of cIMP and the Hyp face are engaged in specific amino acid-nucleotide (His···cIMP) recognition, i.e. by abutting edge-to-edge and by π-π stacking, respectively. The Watson-Crick edge of Hyp and the cIMP phosphate group play a role in nonspecific His···cIMP contacts. The interactions between the cIMP anions (anti/C3'-endo/trans-gauche/chair conformers) are realized mainly between riboses and phosphate groups. The results for this L-His-cIMP complex, compared with those for the previously reported solvated L-His-IMP crystal structure, indicate a different nature of amino acid-nucleotide recognition and interactions upon the 3':5'-cyclization of the nucleotide phosphate group.

  10. La Revolución francesa en marcha: storytelling en la campaña de Mélenchon para las elecciones presidenciales

    Directory of Open Access Journals (Sweden)

    Eugénie Richard

    2013-11-01

    Full Text Available El artículo analiza la utilización del storytelling por los cuatro principales candidatos a la elección presidencial francesa de 2012. Entre ellos se destaca Jean-Luc Mélenchon, candidato del Front de Gauche, que supo aplicar en su campaña estrategias de storyline, de framing y de networking. El candidato revivió el ideal de la Revolución francesa invitando al electorado a unos actos simbólicos de participación política y utilizando el contexto internacional de crisis para posicionar un discurso de “indignado”. A pesar de su semifracaso en las urnas, su campaña fue la más innovadora y dio a conocer nuevas formas de comunicación y de participación en este país poco acostumbrado al uso del storytelling en campaña.

  11. Photoelectron and electron momentum spectroscopy of 1-butene at benchmark theoretical levels

    International Nuclear Information System (INIS)

    Shojaei, S H Reza; Morini, Filippo; Hajgató, Bálazs; Deleuze, Michael S

    2011-01-01

    The results of experimental studies of the valence electronic structure of 1-butene employing photoelectron spectroscopy as well as electron momentum spectroscopy are interpreted on the ground of quantitative calculations of one-electron and shake-up ionization energies and of the related Dyson orbitals, using one-particle Green's function theory in conjunction with the third-order algebraic diagrammatic construction scheme (ADC(3)). Comparison is made with simulations of (e, 2e) electron momentum distributions obtained from standard (B3LYP) Kohn-Sham orbitals. Our analysis is based on highly quantitative determinations of the energy difference between the cis and gauche (C 1 ) conformers, within ∼0.02 kcal mol -1 accuracy, and a thermostatistical evaluation thereby of conformer weights beyond the level of the rigid rotor harmonic oscillator approximation. Relative entropies are found to be particularly sensitive to hindered rotations. The shake-up onset is located at 15.9 eV, and the orbital picture of ionization breaks down completely at electron binding energies above 19 eV. If the available experimental momentum profiles demonstrate the dominance of the C 1 conformer, they are in this case clearly not sensitive enough to the molecular conformation for evaluating conformer abundances with accuracies better than 10% due to the limited energy and momentum resolutions and likely physical complications.

  12. Investigation of the molecular conformations of ethanol using electron momentum spectroscopy

    International Nuclear Information System (INIS)

    Ning, C G; Luo, Z H; Huang, Y R; Liu, K; Zhang, S F; Deng, J K; Hajgato, B; Morini, F; Deleuze, M S

    2008-01-01

    The valence electronic structure and momentum-space electron density distributions of ethanol have been investigated with our newly constructed high-resolution electron momentum spectrometer. The measurements are compared to thermally averaged simulations based on Kohn-Sham (B3LYP) orbital densities as well as one-particle Green's function calculations of ionization spectra and Dyson orbital densities, assuming Boltzmann's statistical distribution of the molecular structure over the two energy minima defining the anti and gauche conformers. One-electron ionization energies and momentum distributions in the outer-valence region were found to be highly dependent upon the molecular conformation. Calculated momentum distributions indeed very sensitively reflect the distortions and topological changes that molecular orbitals undergo due to the internal rotation of the hydroxyl group, and thereby exhibit variations which can be traced experimentally. The B3LYP model Kohn-Sham orbital densities are overall in good agreement with the experimental distributions, and closely resemble benchmark ADC(3) Dyson orbital densities. Both approaches fail to quantitatively reproduce the experimental momentum distributions characterizing the highest occupied molecular orbital. Since electron momentum spectroscopy measurements at various electron impact energies indicate that the plane wave impulse approximation is valid, this discrepancy between theory and experiment is tentatively ascribed to thermal disorder, i.e. large-amplitude and thermally induced dynamical distortions of the molecular structure in the gas phase

  13. Experimental and computational thermochemical study of 3-hydroxypropanenitrile

    International Nuclear Information System (INIS)

    Roux, Maria Victoria; Notario, Rafael; Velez, Ederley; Temprado, Manuel; Guerrero, Andres; Verevkin, Sergey P.; Quijano, Jairo; Gaviria, Jair

    2007-01-01

    This paper reports the values of the standard (p 0 = 0.1 MPa) molar enthalpy of formation in the gas phase, at T = 298.15 K, for 3-hydroxypropanenitrile derived from the respective enthalpy of combustion in oxygen, measured by static bomb combustion calorimetry and the standard molar enthalpy of vaporization, at T = 298.15 K, determined using the transference (transpiration) method in a saturated N 2 stream, the value of the gas-phase enthalpy of formation being Δ f H m 0 (g)=-(91.2±1.4)kJ.mol -1 . Furthermore, we have performed high-level ab initio molecular orbital calculations at the G3 level. Four different conformations corresponding to local minima of the potential energy surface have been found for 3-hydroxypropanenitrile. The optimised molecular and electronic structure of the most stable conformer of 3-hydroxypropanenitrile shows a gauche arrangement with a weak intramolecular hydrogen bond from OH hydrogen to the π-bond charge cloud of the nitrile group. The calculated values for the enthalpy of formation of the most stable conformer using atomization and isodesmic bond separation reactions, -94.7 and -95.0 kJ . mol -1 , respectively, are in very good agreement with the experimental value

  14. Vitamine D et santé osseuse

    Directory of Open Access Journals (Sweden)

    Coxam Véronique

    2014-05-01

    Full Text Available Le calcium est l’élément déterminant de la qualité du squelette parce qu’il lui confère ses propriétés de rigidité. Ainsi, en raison de l’enjeu majeur de santé publique représenté par les atteintes de l’appareil locomoteur chez les séniors, l’optimisation du statut calcique doit donc être assurée par la couverture des besoins définis par les apports nutritionnels conseillés, mais aussi par une potentialisation de sa biodisponibilité. Par conséquent, toute stratégie capable de favoriser l’absorption calcique doit être considérée. C’est pourquoi, la consommation alimentaire de calcium, ainsi que toute calcithérapie, doit être associée à la vitamine D qui, sous sa forme di-hydroxylée, intervient dans le mécanisme de transport actif du minéral à travers la paroi entérocytaire. Ce concept bénéficie d’un consensus et est solidement établi. D’autre part, des études récentes indiquent que la 25(OHD pourrait directement moduler les cellules osseuses qui possèdent, non seulement des récepteurs spécifiques (VDR, mais aussi la 1α-hydroxylase nécessaire à la transformation de la molécule en son métabolite actif. En ce qui concerne la démonstration des effets osseux de la vitamine D, il est évident que l’hyperparathyroïdisme secondaire qui se développe lors d’une déficience du statut en vitaminique D est extrêmement délétère puisque qu’elle engendre une accélération de la résorption. C’est la raison pour laquelle, en situation de carence, une supplémentation peut améliorer le remodelage et la masse osseuse. Toutefois, l’effet reste faible. En revanche, les scientifiques s’accordent à considérer qu’une supplémentation associant calcium et vitamine D peut réduire le risque de fracture, l’intensité dépendant notamment du seuil initial de consommation, de la dose prescrite et bien sûr de l’observance du traitement. Plusieurs méta-analyses ont pu confirmer ces

  15. Scintigraphy of the Pericerebral Subarachnoidspaces; Scintigraphie des Espaces Sous-Arachnoidiens Pericerebraux

    Energy Technology Data Exchange (ETDEWEB)

    Oberson, R.; Martini, T. [Institut Universitaire de Radiologie Medicale, Hopital Cantonal, Lausanne (Switzerland)

    1969-05-15

    cisternographie radioisotopique s' est revelee etre la methode la plus sensible et la seule demonstrative de la presence d'une rhinorrhee ou d'une otorrhee liquidienne), la presence d'un contre-courant ramenant le LCR marque de l'espace sous-arachnoiedien dans les ventricules. Ce dernier phenomene, dit de 'reflux cisterno-ventriculaire' , permet de porter une indication precise a une derivation chirurgicale ventriculo- auriculaire du LCR dans les hydrocephalies symptomatiques de l'adulte ou de l'enfant, d'origine traumatique ou occulte. L'etude exposee dans le memoire se fonde sur l'analyse de plus de 100 scintigraphies des espaces sous- arachnoiediens pericerebraux. Elle permet d'elaborer peu a peu la semiologie normale et pathologique de ce chapitre, tant au point de vue de la morphologie cisternale que sur le plan de l'hydrodynamique liquidienne. (author)

  16. Cerebral Scintigraphy in the Child and Nursing Infant; La Scintigraphie Cerebrale chez l'Enfant et le Nourrisson

    Energy Technology Data Exchange (ETDEWEB)

    Akerman, M.; Rougerie, J.; Guiot, G. [INSERM, Hopital Foch, Suresnes (France)

    1969-05-15

    overall results of cerebral scintigraphy are less favourable in the case of cerebral tumours in children than in that of adults. The reason for this is the high frequency in children of tumours of the brain stem, the pituitary and the third ventricle, the detectability of which is low. However, very good results were obtained in the case of 35 tumours of the cerebellum and the fourth ventricle as a result of using very rigorous techniques. Excellent results have also been obtained with other surgical lesions, such as chronic subdural haematoma in the nursing infant and vascular malformations. In conditions not amenable to neurosurgery definitely false results were the exception. Lastly, the authors present the initial results of a study of the cerebral cisterns and ventricles. They emphasize the abundance of information supplied by these scintigraphic methods and their great utility for the neurosurgeon. (author) [French] La scintigraphie cerebrale chez l' enfant a fait l'objet de peu de travaux publies. Une etude separee chez l' enfant se justifie cependant par les particularites de la pathologie neurochirurgicale infantile. L' exploration de l' enfant et du nourrisson conduit a discuter les donnees dosimetriques et a poser le probleme de la detectabilite des tumeurs de la fosse posterieure, des tumeurs medianes de la base du crane, et des astrocytomes, qui sont justement les tumeurs les plus frequentes en pathologie infantile. Enfin, l' enfant et le nourrisson sont les sujets d'application privilegies des techniques de scintigraphie apres injection locale de composes radioactifs, par voie sous- arachno'idienne, intra-ventriculaire, ou intra-cavitaire, pour 1' etude des hydrocephalies communicantes ou par stenose, des malformations meningo-encephaliques et des hematomes sous-duraux chroniques. En cinq ans ont ete explores 400 enfants et nourrissons ages de 2 mois a 16 ans, soit 10% des 4000 explorations craniennes effectuees dans le laboratoire des auteurs. Parmi ces

  17. Crystallisation and chain conformation of long chain n-alkanes

    International Nuclear Information System (INIS)

    Gorce, J.

    2000-06-01

    Hydrocarbon chains are a basic component in a number of systems as diverse as biological membranes, phospholipids and polymers. A better understanding of the physical properties of n-alkane chains should provide a better understanding of these more complex systems. With this aim, vibrational spectroscopy has been extensively used. This technique, sensitive to molecular details, is the only one able to both identify and quantify conformational disorder present in paraffinic systems. To achieve this, methyl deformations have been widely used as ''internal standards'' for the normalisation of peak areas. However, in the case of n-alkanes with short chain length, such as n-C 44 H 90 for example, the infrared spectra recorded at liquid nitrogen temperature and reported here show the sensitivity of these latter peaks to the various crystal structures formed. Indeed, the main frequencies of the symmetric methyl bending mode were found between 1384 cm -1 and 1368 cm -1 as a function of the crystal form. Changes in the frequency of the first order of the L.A.M. present in the Raman spectra were also observed. At higher temperatures, non all-trans conformers, inferred from different infrared bands present in the wagging mode region, were found to be essentially placed at the end of the n-alkane chains. At the monoclinic phase transition, the concentration of end-gauche conformers, proportional to the area of the infrared band at 1342 cm -1 , increases abruptly. On the contrary, in the spectra recorded at liquid nitrogen temperature no such band is observed. We also studied the degree of disorder in two purely monodisperse long chain n-alkanes, namely n-C 198 H 398 and n-C 246 H 494 . The chain conformation as well as the tilt angle of the chains from the crystal surfaces were determined by means of low frequency Raman spectroscopy and S.A.X.S. measurements on solution-crystallised samples. The increase in the number of end-gauche conformers which was expected to occur with

  18. Mimicking the properties of antifreeze glycoproteins: synthesis and characterization of a model system for ice nucleation and antifreeze studies.

    Science.gov (United States)

    Hederos, Markus; Konradsson, Peter; Borgh, Annika; Liedberg, Bo

    2005-08-25

    Synthesis of beta-D-Gal-(1 --> 3)-beta-D-GalNAc coupled to HOC2H4NHCOC15H30SH is described. This compound was coadsorbed at various proportions with C2H5OC2H4NHCOC15H30SH to form statistically mixed self-assembled monolayers (SAMs) on gold in an attempt to mimic the properties of the active domain in antifreeze glycoproteins (AFGPs). The monolayers were characterized by null ellipsometry, contact angle goniometry, X-ray photoelectron spectroscopy, and infrared reflection-absorption spectroscopy. The disaccharide compound adsorbed preferentially, and SAMs prepared at a solution molar ratio >0.3 displayed total wetting. The mixed SAMs showed well-organized alkyl chains up to a disaccharide surface fraction of 0.8. The amount of gauche conformers in the alkyls increased rapidly above this point, and the monolayers became disordered and less densely packed. Furthermore, the generated mixed SAMs were subjected to water vapor at constant relative humidity and the subsequent ice crystallization on a cooled substrate was monitored via an optical microscope. Interestingly, rapid crystallization occurred within a narrow range of temperatures on mixed SAMs with a high disaccharide content, surface fraction >0.3. The reported crystallization temperatures and the ice layer topography were compared with results obtained for a much simpler reference system composed of -OH/-CH3 terminated n-alkanethiols in order to account for changes in topography of the water/ice layer with surface energy. Although preliminary, the obtained results can be useful in the search for the molecular mechanism behind the antifreeze activity of AFGPs.

  19. Manufacturing of multilayer graphene oxide/poly(ethylene terephthalate) nanocomposites with tunable crystallinity, chain orientations and thermal transitions

    Energy Technology Data Exchange (ETDEWEB)

    Seyyed Monfared Zanjani, Jamal [Faculty of Engineering and Natural Sciences, Sabanci University, Orhanli, 34956 Tuzla, Istanbul (Turkey); Saner Okan, Burcu, E-mail: bsanerokan@sabanciuniv.edu [Sabanci University Nanotechnology Research and Application Center, SUNUM, Orhanli, 34956 Tuzla, Istanbul (Turkey); Nanografen Nanotechnological Products Limited Company, GOSB Teknopark, Gebze 41430, Kocaeli (Turkey); Menceloglu, Yusuf [Faculty of Engineering and Natural Sciences, Sabanci University, Orhanli, 34956 Tuzla, Istanbul (Turkey); Nanografen Nanotechnological Products Limited Company, GOSB Teknopark, Gebze 41430, Kocaeli (Turkey)

    2016-06-15

    Thermally exfoliated graphene oxide (TEGO) reinforced polyethylene terephthalate (PET) nanocomposites with controlled crystallinity, chain conformations and thermo-mechanical properties were produced with very low TEGO weight fractions by a twin-screw compounding extruder. Tensile modulus was found to increase by 52% by the addition of 1 wt% TEGO. This significant increase in mechanical properties of PET nanocomposites was explained by well intercalation of PET chains through multi-layer graphene sheets and complete coverage of graphene surface by electrostatic interactions. An increase in the ratio of gauche and trans conformations in PET chains indicated that PET nanocomposites became more crystalline by increasing TEGO amount. Transmission electron microscopy observations showed the favorable interaction between TEGO sheets and PET matrix facilitating the dispersion and flattening of graphene sheets into polymeric matrix during elongation. The integration of 1 wt% TEGO sheets into PET matrix enhanced heat distortion temperature from 71 °C for neat specimen upto 91.6 °C at the constant stress of 0.45 MPa, and increased Vicat softening point from 76 °C upto 95 °C. Therefore, the failures of PET considerably reduced by improving short-term heat resistance and its softening properties between glass transition temperature and melting temperature by the incorporation of TEGO sheets. - Highlights: • 52% modulus improvement by the addition of 1 wt% graphene in PET. • Well-intercalation of PET chains through graphene sheets during compounding process. • Homogeneous graphene dispersion by favorable interactions between graphene and PET. • Enhancement in Heat distortion temperature and Vicat softening point of PET composite. • Considerable reduction in failures of PET by improving short-term heat resistance.

  20. Polymorphism in R-tamsulosin (an alpha blocker): The unexpected manifestation of a sulfonamide⋯o-diethoxybenzene heterosynthon

    Science.gov (United States)

    Nanubolu, Jagadeesh Babu; Sridhar, Balasubramanian; Ravikumar, Krishnan

    2014-12-01

    A two point Nsbnd H⋯O dimer or an infinite catemer are the most preferred motifs/synthons for sulfonamide structures. Such synthons are known to be so robust that they are only disrupted in the presence of highly activated O acceptors such as pyridine-N-oxide and sulfoxide. We demonstrate in this article that a multi-point synthon offered by much weaker ethoxy O and amine N acceptors can however strongly compete and disrupt the robust sulfonamide homosynthons. This has been illustrated with the synthon analysis in three polymorphic crystal structures of R-tamsulosin, an active drug used in the treatment of Benign Prostatic Hyperplasia (BPH) and its hydrochloride salt. These crystalline solids are characterized by Single crystal X-ray diffraction (SC-XRD), powder X-ray diffraction (PXRD), Fourier Transform Infrared (FT-IR) and Raman spectroscopy. Forms I, II of the free base and hydrochloride salt crystallize in the monoclinic P21, C2, and P21 space groups respectively with two molecules in the asymmetric unit (Z‧ = 2), whereas, form III of freebase crystallize in the orthorhombic P212121 space group with Z‧ = 1. Remarkably, all four crystal structures contain a totally unexpected sulfonamide⋯o-diethoxybenzene heterosynthon. The multi-point motifs observed in polymorphs are relatively stronger than those in the hydrochloride salt because of the gauche conformation of the tamsulosin linker chain which renders an additional hydrogen bond interaction with amine N acceptor, and resemble the crown ether sulfonamide recognition pattern. Observation of this new heterosynthon offers potential scope in the design of pharmaceutical cocrystals for sulfonamide bearing drug molecules. The present study also presents a detailed hydrogen bond motif analysis in 310 primary sulfonamide structures culled from the latest version of Cambridge Structural Database (CSD). The role of various competing groups is discussed in the context of understanding the most recurring

  1. A Library in the Grands Moulins de Paris: challenging Reality

    Directory of Open Access Journals (Sweden)

    Catherine Tresson

    2006-07-01

    Full Text Available In 2006, the University of Paris 7 and its new Main Library will move to Paris Rive Gauche, a recently developed neighbourhood on the left bank of the Seine. The library will occupy most of the city’s former industrial mills, the Grands Moulins de Paris. As part of the project, the library developed a very detailed functional program. The facilities are expected to comprise 1,800 workstations (half of which will be computerized, and upon completion will have a capacity of 300,000 freely accessible documents and 350,000 documents in store over a total surface area of some 12,000 m2. The architect Rudy Ricciotti won the international competition to design the library held in 2001. Perfectly suited to its function, the industrial building in which the library is housed dates from the 1920s. It presents both advantages (vast surfaces, sufficient load-bearing capacity, natural light, etc. and obstacles (restrictions on free circulation, forests of columns in certain areas, interrupted spaces, etc. to being transformed into a library that is functional and adapted to its purposes. The building’s structure and the constraints it imposed profoundly influenced the program which had to be adjusted, and also affected other aspects, including the arrangement and features of the furnishings as well as the building’s system of signs. In agreement with the university, the library worked in close collaboration with the architect from the earliest sketches onwards. As a result, his initial plan also evolved considerably. The installation of the library in the Grands Moulins offers us a chance to observe the nature and effects of the interactions between the transformation of a building and the evolution of a program.

  2. Poussée de maladie de Kaposi et élévation du CA 19-9: penser à la tuberculose!

    Science.gov (United States)

    Ajili, Faida; Hariz, Héla; Souissi, Asmahen; Abid, Rim; Boussetta, Najeh; Laabidi, Besma; Battikh, Riadh; Louzir, Bassem; Othmani, Salah

    2013-01-01

    La maladie de Kaposi (MK) est une entité pathologique qui peut survenir chez les patients VIH positifs et dans le cadre d'une immunodépression, d'origine tuberculeuse très rarement. On décrit le cas d'une MK chez un patient VIH négatif au décours d'une tuberculose. Nous rapportons le cas d'un patient âgé de 81 ans, VIH négatif, ayant présenté deux nodules angiomateux de l'avant bras gauche dont la biopsie cutanée était en faveur d'une MK. L’évolution était marquée 2 mois plus tard, par l'apparition de placards angiomateux extensifs des deux membres supérieurs et d'adénopathies cervicales jugulo-carotidiennes bilatérales. La biopsie ganglionnaire était en faveur d'une tuberculose ganglionnaire. Par ailleurs, il avait un taux sérique élevé des CA 19-9. La régression de l’étendue des lésions au niveau des membres supérieurs et la normalisation du taux sérique des CA 19-9 ont été obtenues sous traitement anti-tuberculeux. Chez les patients atteints d'une MK avec une élévation des CA 19-9, il faut penser à la tuberculose. PMID:24711871

  3. Pyélonéphrite xanthogranulomateuse bilatérale focale : à propos d’un cas

    Science.gov (United States)

    El Yacoubi, Souhail; Ziouziou, Imad; Zizi, Mohamed; Jahid, Ahmed; Karmouni, Tariq; El Khader, Khalid; Koutani, Abdellatif; Andaloussi, Ahmed Iben Attya

    2014-01-01

    Résumé Nous présentons l’observation clinique d’un cas rare de pyélonéphrite xanthogranulomateuse (PXG) bilatérale chez un jeune patient âgé de 17 ans. La découverte progressive de l’infection a débuté par l’apparition de lombalgies bilatérales évoluant depuis un mois, sans autre signe associé. L’urotomodensitométrie penchait en faveur de deux masses rénales bilatérales, soit une masse polaire inférieure droite et une masse polaire supérieure gauche, toutes deux de densité tissulaire. Une biopsie échoguidée a suggéré la présence d’une réaction inflammatoire non spécifique. Une néphrectomie partielle polaire inférieure droite a été effectuée devant la forte présomption de tumeurs rénales malignes. Finalement, l’histologie a orienté le diagnostic vers une PXG. Il s’agit, à notre connaissance, du sixième cas de PXG focale bilatérale rapporté dans la littérature. Notre patient a reçu un traitement antibiotique à base de fluoroquinolone pendant un mois. L’évolution clinique s’est avérée bonne, et les lésions visibles à la tomodensitométrie se sont entièrement résorbées au bout d’un mois. Le patient vit toujours après un an et présente une fonction rénale normale. PMID:25295145

  4. Pressure dependence of side chain 13C chemical shifts in model peptides Ac-Gly-Gly-Xxx-Ala-NH2.

    Science.gov (United States)

    Beck Erlach, Markus; Koehler, Joerg; Crusca, Edson; Munte, Claudia E; Kainosho, Masatsune; Kremer, Werner; Kalbitzer, Hans Robert

    2017-10-01

    For evaluating the pressure responses of folded as well as intrinsically unfolded proteins detectable by NMR spectroscopy the availability of data from well-defined model systems is indispensable. In this work we report the pressure dependence of 13 C chemical shifts of the side chain atoms in the protected tetrapeptides Ac-Gly-Gly-Xxx-Ala-NH 2 (Xxx, one of the 20 canonical amino acids). Contrary to expectation the chemical shifts of a number of nuclei have a nonlinear dependence on pressure in the range from 0.1 to 200 MPa. The size of the polynomial pressure coefficients B 1 and B 2 is dependent on the type of atom and amino acid studied. For H N , N and C α the first order pressure coefficient B 1 is also correlated to the chemical shift at atmospheric pressure. The first and second order pressure coefficients of a given type of carbon atom show significant linear correlations suggesting that the NMR observable pressure effects in the different amino acids have at least partly the same physical cause. In line with this observation the magnitude of the second order coefficients of nuclei being direct neighbors in the chemical structure also are weakly correlated. The downfield shifts of the methyl resonances suggest that gauche conformers of the side chains are not preferred with pressure. The valine and leucine methyl groups in the model peptides were assigned using stereospecifically 13 C enriched amino acids with the pro-R carbons downfield shifted relative to the pro-S carbons.

  5. Experimentally driven atomistic model of 1,2 polybutadiene

    Energy Technology Data Exchange (ETDEWEB)

    Gkourmpis, Thomas, E-mail: thomas.gkourmpis@borealisgroup.com [Polymer Science Centre, J. J. Thomson Physical Laboratory, Department of Physics, University of Reading, Reading RG6 6AF (United Kingdom); Mitchell, Geoffrey R. [Polymer Science Centre, J. J. Thomson Physical Laboratory, Department of Physics, University of Reading, Reading RG6 6AF (United Kingdom); Centre for Rapid and Sustainable Product Development, Institute Polytechnic Leiria, Marinha Grande (Portugal)

    2014-02-07

    We present an efficient method of combining wide angle neutron scattering data with detailed atomistic models, allowing us to perform a quantitative and qualitative mapping of the organisation of the chain conformation in both glass and liquid phases. The structural refinement method presented in this work is based on the exploitation of the intrachain features of the diffraction pattern and its intimate linkage with atomistic models by the use of internal coordinates for bond lengths, valence angles, and torsion rotations. Atomic connectivity is defined through these coordinates that are in turn assigned by pre-defined probability distributions, thus allowing for the models in question to be built stochastically. Incremental variation of these coordinates allows for the construction of models that minimise the differences between the observed and calculated structure factors. We present a series of neutron scattering data of 1,2 polybutadiene at the region 120–400 K. Analysis of the experimental data yields bond lengths for Cî—¸C and C î—» C of 1.54 Å and 1.35 Å, respectively. Valence angles of the backbone were found to be at 112° and the torsion distributions are characterised by five rotational states, a three-fold trans-skew± for the backbone and gauche± for the vinyl group. Rotational states of the vinyl group were found to be equally populated, indicating a largely atactic chan. The two backbone torsion angles exhibit different behaviour with respect to temperature of their trans population, with one of them adopting an almost all trans sequence. Consequently, the resulting configuration leads to a rather persistent chain, something indicated by the value of the characteristic ratio extrapolated from the model. We compare our results with theoretical predictions, computer simulations, RIS models and previously reported experimental results.

  6. Searching for trans ethyl methyl ether in Orion KL.

    Science.gov (United States)

    Tercero, B; Cernicharo, J; López, A; Brouillet, N; Kolesniková, L; Motiyenko, R A; Margulès, L; Alonso, J L; Guillemin, J-C

    2015-10-01

    We report on the tentative detection of trans ethyl methyl ether (tEME), t-CH 3 CH 2 OCH 3 , through the identification of a large number of rotational lines from each one of the spin states of the molecule towards Orion KL. We also search for gauche-trans-n-propanol, Gt-n-CH 3 CH 2 CH 2 OH, an isomer of tEME in the same source. We have identified lines of both species in the IRAM 30 m line survey and in the ALMA Science Verification data. We have obtained ALMA maps to establish the spatial distribution of these species. Whereas tEME mainly arises from the compact ridge component of Orion, Gt-n-propanol appears at the emission peak of ethanol (south hot core). The derived column densities of these species at the location of their emission peaks are ≤(4.0 ± 0.8) × 10 15 cm -2 and ≤(1.0 ± 0.2)× 10 15 cm -2 for tEME and Gt-n-propanol, respectively. The rotational temperature is ~100 K for both molecules. We also provide maps of CH 3 OCOH, CH 3 CH 2 OCOH, CH 3 OCH 3 , CH 3 OH, and CH 3 CH 2 OH to compare the distribution of these organic saturated O-bearing species containing methyl and ethyl groups in this region. Abundance ratios of related species and upper limits to the abundances of non-detected ethers are provided. We derive an abundance ratio N (CH 3 OCH 3 )/ N (tEME) ≥ 150 in the compact ridge of Orion.

  7. Searching for trans ethyl methyl ether in Orion KL★,★★

    Science.gov (United States)

    Tercero, B.; Cernicharo, J.; López, A.; Brouillet, N.; Kolesniková, L.; Motiyenko, R. A.; Margulès, L.; Alonso, J. L.; Guillemin, J.-C.

    2015-01-01

    We report on the tentative detection of trans ethyl methyl ether (tEME), t-CH3CH2OCH3, through the identification of a large number of rotational lines from each one of the spin states of the molecule towards Orion KL. We also search for gauche-trans-n-propanol, Gt-n-CH3CH2CH2OH, an isomer of tEME in the same source. We have identified lines of both species in the IRAM 30 m line survey and in the ALMA Science Verification data. We have obtained ALMA maps to establish the spatial distribution of these species. Whereas tEME mainly arises from the compact ridge component of Orion, Gt-n-propanol appears at the emission peak of ethanol (south hot core). The derived column densities of these species at the location of their emission peaks are ≤(4.0 ± 0.8) × 1015 cm−2 and ≤(1.0 ± 0.2)× 1015 cm−2 for tEME and Gt-n-propanol, respectively. The rotational temperature is ~100 K for both molecules. We also provide maps of CH3OCOH, CH3CH2OCOH, CH3OCH3, CH3OH, and CH3CH2OH to compare the distribution of these organic saturated O-bearing species containing methyl and ethyl groups in this region. Abundance ratios of related species and upper limits to the abundances of non-detected ethers are provided. We derive an abundance ratio N(CH3OCH3)/N(tEME) ≥ 150 in the compact ridge of Orion. PMID:26869726

  8. Group 13 ligand supported heavy-metal complexes: first structural evidence for gallium-lead and gallium-mercury bonds.

    Science.gov (United States)

    Prabusankar, Ganesan; Gemel, Christian; Winter, Manuela; Seidel, Rüdiger W; Fischer, Roland A

    2010-05-25

    Heavy-metal complexes of lead and mercury stabilized by Group 13 ligands were derived from the oxidative addition of Ga(ddp) (ddp=HC(CMeNC(6)H(3)-2,6-iPr(2))(2), 2-diisopropylphenylamino-4-diisopropyl phenylimino-2-pentene) with corresponding metal precursors. The reaction of Me(3)PbCl and Ga(ddp) afforded compound [{(ddp)Ga(Cl)}PbMe(3)] (1) composed of Ga-Pb(IV) bonds. In addition, the monomeric plumbylene-type compound [{(ddp)Ga(OSO(2)CF(3))}(2)Pb(thf)] (2a) with an unsupported Ga-Pb(II)-Ga linkage was obtained by the reaction of [Pb(OSO(2)CF(3))(3)] with Ga(ddp) (2 equiv). Compound 2a falls under the rare example of a discrete plumbylene-type compound supported by a nonclassical ligand. Interesting structural changes were observed when [Pb(OSO(2)CF(3))(3)]2.H(2)O was treated with Ga(ddp) in a 1:2 ratio to yield [{(ddp)Ga(mu-OSO(2)CF(3))}(2)(OH(2))Pb] (2b) at below -10 degrees C. Compound 2b consists of a bent Ga-Pb-Ga backbone with a bridging triflate group between the Ga-Pb bond and a weakly interacting water molecule at the gallium center. Similarly, the reaction of mercury thiolate Hg(SC(6)F(5)) with Ga(ddp) (2 equiv) produced the bimetallic homoleptic compounds anti-[{(ddp)Ga(SC(6)F(5))}(2)Hg] (3a) and gauche-[{(ddp)Ga(SC(6)F(5))}(2)Hg] (3b), respectively, with a linear Ga-Hg-Ga linkage. Compounds 1-3 were structurally characterized and these are the first examples of compounds comprised of Ga-Pb(II), Ga-Pb(IV), and Ga-Hg bonds.

  9. Crystal structures of [Ln(NO33(μ2-bpydo2], where Ln = Ce, Pr or Nd, and bpydo = 4,4′-bipyridine N,N′-dioxide: layered coordination networks containing 44 grids

    Directory of Open Access Journals (Sweden)

    Michael L. Stromyer

    2016-01-01

    Full Text Available Three isostructural coordination networks of Ce, Pr, and Nd nitrate with 4,4′-bipyridine N,N′-dioxide (bpydo are reported, namely poly[[tris(nitrato-κ2O,O′cerium(III]-bis(μ2-4,4′-bipyridine N,N′-dioxide-κ2N:N′], [Ce(NO33(C10H8N2O22], poly[[tris(nitrato-κ2O,O′praeseodymium(III]-bis(μ2-4,4′-bipyridine N,N′-dioxide-κ2N:N′], [Pr(NO33(C10H8N2O22], and poly[[tris(nitrato-κ2O,O′neodymium(III]-bis(μ2-4,4′-bipyridine N,N′-dioxide-κ2N:N′], [Nd(NO33(C10H8N2O22]. All three compounds are isostructural to the previously reported La analogue. The asymmetric unit of [Ln(NO33(μ2-bpydo2] contains one lanthanide cation, two bpydo ligands, and three nitrate anions. Both bpydo ligands act as end-to-end μ2-bridges and display nearly ideal cis and gauche conformations, respectively. The bpydo ligands link the ten-coordinate LnIII cations, forming interdigitating 44 grid-like layers extending parallel to (-101, where interdigitation of layers is promoted by C—H...O interactions between nitrate anions and bpydo ligands. The interdigitated layers are linked to sets of neighboring layers via further C—H...O and π–π interactions.

  10. Chemical modifications of polymer films induced by high energy heavy ions

    International Nuclear Information System (INIS)

    Zhu Zhiyong; Sun Youmei; Liu Changlong; Liu Jie; Jin Yunfan

    2002-01-01

    Polymer films including polyethylene terephthalate (PET), polystyrene (PS) and polycarbonate (PC) were irradiated at room temperature with ions of 35 MeV/u 40 Ar, 25 MeV/u 84 Kr, 15.1 MeV/u 136 Xe and 11.4 MeV/u 238 U to fluences ranging from 9x10 9 to 5.5x10 12 ions/cm 2 . The radiation-induced chemical changes of the materials were investigated by Fourier-transform infrared (FTIR) and ultraviolet/visible spectroscopies. It is found that the absorbance in the ultraviolet and visible range induced by all irradiations follows a linear relationship with fluence. The radiation-induced absorbance normalized to one particle increases slowly with increasing of electronic energy loss below about 8 keV/nm followed by a sharp increase up to about 15 keV/nm above which saturation is reached. FTIR measurements reveal that the materials suffer serious degradation through bond breaking. The absorbance of the typical infrared bands decays exponentially with increase of ion fluence and the bond-disruption cross-section shows a sigmoid variation with electronic energy loss. In PET loss of crystallinity is attributed to the configuration transformation of the ethylene glycol residue from trans into the gauche. Alkyne end groups are induced in all the materials above certain electronic energy loss threshold, which is found to be about 0.8 keV/nm for PS and 0.4 keV/nm for PC. The production cross-section of alkyne end group increases with increasing of electronic energy loss and shows saturation at high electronic energy loss values. It is concluded that not only the physical processes but also the chemical processes of the energy deposition determine the modification of polymer

  11. Determination of molecular structure of succinic acid in a very complex conformational landscape: Gas-phase electron diffraction (GED) and ab initio studies

    Science.gov (United States)

    Vogt, Natalja; Abaev, Maxim A.; Rykov, Anatolii N.; Shishkov, Igor F.

    2011-06-01

    The molecular structure of succinic acid has been investigated by the gas-phase electron diffraction (GED) method for the first time. According to predictions of MP2/cc-pVTZ calculations, the molecule has 18 stable conformers with the C sbnd C sbnd C sbnd C chain in the gauche ( G) or anti ( A) configuration, and four of them, I ( G), II ( A), III ( G) and IV ( A) belonging to the C 2, C 2h, C 1 and C 1 point groups, respectively, with relative energies ΔE ZPE within 2.2 kcal/mol can be present at the experimental temperature of 445 K in noticeable amounts. The ratio of the conformers I:II:III:IV = 45(15):20(15):10(assumed):25(15) (in %) has been determined in the GED analysis guided by theoretical predictions. To take into account vibrational effects, the corrections Δ( r e - r a) to the experimental r a bond lengths were calculated from the MP2/cc-pVTZ quadratic and cubic force constants. The obtained equilibrium structural parameters of the dominant conformer I are the following (bond lengths in Å, angles in degrees): r e(C sp3sbnd C sp3) = 1.508(3), r e(C sp3sbnd C sp2) = 1.499(2), r e(C sbnd O) = 1.343(2), r e(C dbnd O) = 1.202(1), e(C sbnd C sbnd C) = 111.8(4), e(C sbnd C sbnd O) = 112.0(4), e(O sbnd C dbnd O) = 123.0(1), τ(C sbnd C sbnd C sbnd C) = 69.9(11). Yielding the best agreement with the GED structure, the MP2/cc-pVQZ approximation overestimates the C sbnd O and C dbnd O bond lengths by ca. 0.005(2) Å.

  12. Vibrational spectra and assignments for cis- and trans-1,2-difluorocyclopropane and three deuterium substituted modifications of each isomer

    International Nuclear Information System (INIS)

    Craig, N.C.; Hu Chao, T.N.; Cuellar, E.; Hendriksen, D.E.; Koepke, J.W.

    1975-01-01

    Infrared spectra under a variety of experimental conditions and Raman spectra for the liquid phase have been recorded for the cis and trans isomers of 1,2-difluorocyclopropane and the 1,2-d 2 , 3,3-d 2 , and d 4 deuterated modifications. Almost all of the 168 fundamentals of this set of eight molecules have been observed and assigned convincingly. For cis-1,2-difluorocyclopropane-d 0 the fundamentals are (a') 3105, 3063, 3023, 1450, 1365, 1224, 1135, 1047, 862, 784, 468, 209 cm -1 ; (a'') 3055, 1346, 1150, 1089, 1060, 993, 739, 621, 319 cm -1 . For trans-1,2-difluorocyclopropane-d 0 the fundamentals are (a) 3070, 3021, 1457, 1380, 1203, 1132, 1068, 961, 842, 415, 279 cm -1 ; (b) 3110, 3070, 1304, 1161, 1072, 1005, 937, 783, 452, 303 cm -1 . Only the 1089-cm -1 mode in the cis and the 937-cm -1 mode in the trans are in doubt. Group frequency descriptions are discussed qualitatively, and attention is drawn to the fundamentals near 1450 cm -1 which are characteristic of fluorocyclopropanes and appear to be largely due to ring stretching. From previously published equilibrium data for the cis-to-trans isomerization and the fundamental frequencies of the two isomers, an electronic energy difference of -2800 +- 200 cal/mol has been calculated. In contrast, the trans isomer of 1,2-difluoroethylene has an energy 1100 cal/mol greater than the cis, and the trans rotamer of 1,2-difluoroethane has an energy about 600 cal/mol greater than the gauche. (auth)

  13. The relationship of physico-chemical properties and structure to the differential antiplasmodial activity of the cinchona alkaloids

    Directory of Open Access Journals (Sweden)

    Meyer David J

    2003-09-01

    Full Text Available Abstract Background The 8-amino and 9-hydroxy substituents of antimalarial cinchona alkaloids have the erythro orientation while their inactive 9-epimers are threo. From the X-ray structures a 90° difference in torsion angle between the N1-H1 and C9-O12 bonds in the two series is believed to be important. In order to kill the malaria parasite, alkaloids must cross the erythrocyte and parasite membranes to accumulate in the acid digestive vacuole where they prevent detoxication of haematin produced during haemoglobin breakdown. Methods Ionization constants, octanol/water distribution and haematin interaction are examined for eight alkaloids to explain the influence of small structural differences on activity. Results Erythro isomers have a high distribution ratio of 55:1 from plasma to the erythrocyte membrane, while for the more basic threo epimers this is only 4.5:1. This gives an increased transfer rate of the erythro drugs into the erythrocyte and thence into the parasite vacuole where their favourable conformation allows interaction with haematin, inhibiting its dimerization strongly (90 ± 7% and thereby killing the parasite. The threo compounds not only enter more slowly but are then severely restricted from binding to haematin by the gauche alignment of their N1-H1 and C9-O12 bonds. Confirmatory molecular models allowed measurement of angles and bond lengths and computation of the electronic spectrum of a quinine-haematin complex. Conclusion Differences in the antiplasmodial activity of the erythro and threo cinchona alkaloids may therefore be attributed to the cumulative effects of lipid/aqueous distribution ratio and drug-haematin interaction. Possible insights into the mechanism of chloroquine-resistance are discussed.

  14. Eicosapentaenoic acid and docosahexaenoic acid have distinct membrane locations and lipid interactions as determined by X-ray diffraction.

    Science.gov (United States)

    Sherratt, Samuel C R; Mason, R Preston

    2018-01-31

    Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) differentially influence lipid oxidation, signal transduction, fluidity, and cholesterol domain formation, potentially due in part to distinct membrane interactions. We used small angle X-ray diffraction to evaluate the EPA and DHA effects on membrane structure. Membrane vesicles composed of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and cholesterol (C) (0.3C:POPC mole ratio) were prepared and treated with vehicle, EPA, or DHA (1:10 mol ratio to POPC). Electron density profiles generated from the diffraction data showed that EPA increased membrane hydrocarbon core electron density over a broad area, up to ± 20 Å from the membrane center, indicating an energetically favorable extended orientation for EPA likely stabilized by van der Waals interactions. By contrast, DHA increased electron density in the phospholipid head group region starting at ± 12 Å from the membrane center, presumably due to DHA-surface interactions, with coincident reduction in electron density in the membrane hydrocarbon core centered ± 7-9 Å from the membrane center. The membrane width (d-space) decreased by 5 Å in the presence of vehicle as the temperature increased from 10 °C to 30 °C due to increased acyl chain trans-gauche isomerizations, which was unaffected by addition of EPA or DHA. The influence of DHA on membrane structure was modulated by temperature changes while the interactions of EPA were unaffected. The contrasting EPA and DHA effects on membrane structure indicate distinct molecular locations and orientations that may contribute to observed differences in biological activity. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

  15. Elastin-like Polypeptide Linkers for Single-Molecule Force Spectroscopy.

    Science.gov (United States)

    Ott, Wolfgang; Jobst, Markus A; Bauer, Magnus S; Durner, Ellis; Milles, Lukas F; Nash, Michael A; Gaub, Hermann E

    2017-06-27

    Single-molecule force spectroscopy (SMFS) is by now well established as a standard technique in biophysics and mechanobiology. In recent years, the technique has benefitted greatly from new approaches to bioconjugation of proteins to surfaces. Indeed, optimized immobilization strategies for biomolecules and refined purification schemes are being steadily adapted and improved, which in turn has enhanced data quality. In many previously reported SMFS studies, poly(ethylene glycol) (PEG) was used to anchor molecules of interest to surfaces and/or cantilever tips. The limitation, however, is that PEG exhibits a well-known trans-trans-gauche to all-trans transition, which results in marked deviation from standard polymer elasticity models such as the worm-like chain, particularly at elevated forces. As a result, the assignment of unfolding events to protein domains based on their corresponding amino acid chain lengths is significantly obscured. Here, we provide a solution to this problem by implementing unstructured elastin-like polypeptides as linkers to replace PEG. We investigate the suitability of tailored elastin-like polypeptides linkers and perform direct comparisons to PEG, focusing on attributes that are critical for single-molecule force experiments such as linker length, monodispersity, and bioorthogonal conjugation tags. Our results demonstrate that by avoiding the ambiguous elastic response of mixed PEG/peptide systems and instead building the molecular mechanical systems with only a single bond type with uniform elastic properties, we improve data quality and facilitate data analysis and interpretation in force spectroscopy experiments. The use of all-peptide linkers allows alternative approaches for precisely defining elastic properties of proteins linked to surfaces.

  16. Otite externe maligne à Candida Albicans

    Science.gov (United States)

    Elayoubi, Fahd; Lachkar, Azeddine; Aabach, Ahmed; Chouai, Mohamed; Ghailan, Mohamed Rachid

    2016-01-01

    L’otite externe maligne est une ostéomyélite de la base du crane. Le Pseudomonas aeruginosa est le germe le plus incriminé. Cependant l’origine fongique n’est pas rare. Patiente âgée de 80 ans avait présenté une otalgie gauche persistante depuis deux mois malgré un traitement bien conduit. L’examen otologique mettait en évidence des signes inflammatoires au niveau du pavillon, une sténose du conduit avec des granulomes, et otorrhée d’allure purulente. Le scanner montrait un comblement otomastoïdien, un processus inflammatoire extensif des tissus pré et rétro-auriculaire et une lyse du tympanal. Vu l’absence d’amélioration un examen mycologique a été réalisé et qui a révélé la présence de Candida Albicans. Les cas d’otite externe maligne à Candida Albicans sont rarement rapportés. L’origine fongique doit être suspecté devant la négativité des prélèvements bactériologiques et la non amélioration malgré un traitement antibiotique bien conduit, et confirmée par des prélèvements mycologiques parfois multiples. L’otite externe maligne à Candida Albicans est une infection rare potentiellement mortelle. PMID:28154677

  17. PyCPR - a python-based implementation of the Conjugate Peak Refinement (CPR) algorithm for finding transition state structures.

    Science.gov (United States)

    Gisdon, Florian J; Culka, Martin; Ullmann, G Matthias

    2016-10-01

    Conjugate peak refinement (CPR) is a powerful and robust method to search transition states on a molecular potential energy surface. Nevertheless, the method was to the best of our knowledge so far only implemented in CHARMM. In this paper, we present PyCPR, a new Python-based implementation of the CPR algorithm within the pDynamo framework. We provide a detailed description of the theory underlying our implementation and discuss the different parts of the implementation. The method is applied to two different problems. First, we illustrate the method by analyzing the gauche to anti-periplanar transition of butane using a semiempirical QM method. Second, we reanalyze the mechanism of a glycyl-radical enzyme, namely of 4-hydroxyphenylacetate decarboxylase (HPD) using QM/MM calculations. In the end, we suggest a strategy how to use our implementation of the CPR algorithm. The integration of PyCPR into the framework pDynamo allows the combination of CPR with the large variety of methods implemented in pDynamo. PyCPR can be used in combination with quantum mechanical and molecular mechanical methods (and hybrid methods) implemented directly in pDynamo, but also in combination with external programs such as ORCA using pDynamo as interface. PyCPR is distributed as free, open source software and can be downloaded from http://www.bisb.uni-bayreuth.de/index.php?page=downloads . Graphical Abstract PyCPR is a search tool for finding saddle points on the potential energy landscape of a molecular system.

  18. La fibrillation atriale, fréquence, facteurs étiologiques, évolution et traitement dans un service de cardiologie de Dakar, Sénégal

    Directory of Open Access Journals (Sweden)

    Kane Abdoul

    2010-09-01

    Full Text Available INTRODUCTION: La fibrillation atriale est le trouble du rythme cardiaque soutenu le plus fréquent. Les objectifs de ce travail étaient d’étudier la fréquence, les facteurs étiologiques, l’évolution et le traitement de la fibrillation atriale dans un service de cardiologie de Dakar au Sénégal. METHODES: Il s’agit d’une étude rétrospective réalisée sur cinq ans et portant sur l’analyse de 150 dossiers de patients hospitalisés pour une fibrillation atriale. RESULTATS: La fréquence de la fibrillation atriale était de 5,35 % et représentait 66% des troubles du rythme cardiaque avec une prédominance féminine (sex-ratio H/F = 0,45 et un âge moyen de 57,06 ± 18,64 ans. L’origine de la fibrillation était valvulaire dans 36,7% des cas. Les complications thromboemboliques étaient plus fréquentes dans la fibrillation atriale non valvulaire (p=0,006, chez les sujets d’âge > 50 ans (p=0,01 et en cas de dilatation de l’oreillette gauche (p=0,05. Une anticoagulation par anti-vitamine K était instaurée dans 62% des cas et un traitement de contrôle de la fréquence cardiaque dans 87,33%. CONCLUSION: La fibrillation atriale est fréquente en milieu hospitalier africain et concerne des sujets relativement jeunes. L’hypertension artérielle et les valvulopathies rhumatismales sont les principaux facteurs étiologiques. Le traitement reste essentiellement médicamenteux par contrôle de la fréquence cardiaque.

  19. Standardissimo. Les limitations théoriques du Modèle Standard. Quelles réponses y apporter?

    Science.gov (United States)

    Renard, F. M.

    Nous présentons I 'état du Modèle Standard des interactions fortes, faibles et électromagnétiques. Après une description rapide de ses 3 secteurs, secteur de jauge (radiation), secteur fermionique (matière) et secteur scalaire (génération des masses), nous insistons sur le grand nombre de paramètres libres et sur les choix arbitraires qu'il a fallu faire dans l'élaboration du modèle. Nous faisons ressortir les problèmes techniques non résolus et nous dressons la liste des questions fondamentales restées sans réponses. Nous passons ensuite en revue les idées et méthodes proposées pour répondre à ces questions. Elles utilisent essentiellement 3 voies différentes. La première consiste à requérir plus de symétrie (extension du modèle, symétrie Gauche-Droite, Grandes Unifications, Supersymétrie,...). La seconde contient les diverses alternatives au Modèle Standard impliquant des modifications dans certains secteurs (par exemple le secteur scalaire avec le modèle de la Technicouleur) ou de façon plus violente l'hypothèse d'une sous-structure des leptons, des quarks et des bosons W et Z eux-mêmes. Une dernière voie cherche à justifier les particularités du Modèle Standard et relier ses paramètres libres en se basant sur des principes de cohérence interne du modèle. Les conséquences observables de ces diverses approches sont dans chaque cas mentionnées.

  20. Structure and phase transitions of monolayers of intermediate-length n-alkanes on graphite studied by neutron diffraction and molecular dynamics simulation

    Science.gov (United States)

    Diama, A.; Matthies, B.; Herwig, K. W.; Hansen, F. Y.; Criswell, L.; Mo, H.; Bai, M.; Taub, H.

    2009-08-01

    We present evidence from neutron diffraction measurements and molecular dynamics (MD) simulations of three different monolayer phases of the intermediate-length alkanes tetracosane (n-C24H50 denoted as C24) and dotriacontane (n-C32H66 denoted as C32) adsorbed on a graphite basal-plane surface. Our measurements indicate that the two monolayer films differ principally in the transition temperatures between phases. At the lowest temperatures, both C24 and C32 form a crystalline monolayer phase with a rectangular-centered (RC) structure. The two sublattices of the RC structure each consists of parallel rows of molecules in their all-trans conformation aligned with their long axis parallel to the surface and forming so-called lamellas of width approximately equal to the all-trans length of the molecule. The RC structure is uniaxially commensurate with the graphite surface in its [110] direction such that the distance between molecular rows in a lamella is 4.26 Å=√3 ag, where ag=2.46 Å is the lattice constant of the graphite basal plane. Molecules in adjacent rows of a lamella alternate in orientation between the carbon skeletal plane being parallel and perpendicular to the graphite surface. Upon heating, the crystalline monolayers transform to a "smectic" phase in which the inter-row spacing within a lamella expands by ˜10% and the molecules are predominantly oriented with the carbon skeletal plane parallel to the graphite surface. In the smectic phase, the MD simulations show evidence of broadening of the lamella boundaries as a result of molecules diffusing parallel to their long axis. At still higher temperatures, they indicate that the introduction of gauche defects into the alkane chains drives a melting transition to a monolayer fluid phase as reported previously.

  1. Política estadual e desigualdade: por que alguns estados redistribuem mais do que outros?

    Directory of Open Access Journals (Sweden)

    Natália Guimarães Duarte Sátyro

    2013-09-01

    Full Text Available Dans cet article, on examine la variation des types d'inégalité du revenu dans les États du Brésil, issue de la charpente politico-institutionnelle du pays. On avance que les facteurs politiques à l'échelon de chaque État agissent sur la distribution des revenus, aussi bien par l'amélioration du capital humain, c'est-à-dire en investissant dans l'éducation, qu'en le faisant dans des politiques de formation professionnelle ou encore dans des politiques qui rendent les espaces régionaux plus attirants pour les investissements privés. Cette étude couvre tous les États du Brésil ainsi que le Distrito Federal pendant la période 1992 - 2006. L'analyse empirique s'est servie d'estimations de modèles de régression Prais-Winsten avec panel corrected standard error model (PCSE-AR1. Selon les résultats, malgré les restrictions financières imposées aux États pendant cette période, la compétition politique et les partis des États à leur niveau gouvernemental n'ont pas produit les mêmes modèles de redistribution. On trouve pourtant des résultats controversés en ce qui concerne le rôle de la gauche, ce qui suggère la poursuite de cette étude.

  2. Effect of Ring Size in ω-Alicyclic Fatty Acids on the Structural and Dynamical Properties Associated with Fluidity in Lipid Bilayers.

    Science.gov (United States)

    Poger, David; Mark, Alan E

    2015-10-27

    Fatty acids containing a terminal cyclic group such as cyclohexyl and cycloheptyl are commonly found in prokaryotic membranes, especially in those of thermo-acidophilic bacteria. These so-called ω-alicyclic fatty acids have been proposed to stabilize the membranes of bacteria by reducing the fluidity in membranes and increasing lipid packing and lipid chain order. In this article, molecular dynamics simulations are used to examine the effect of 3- to 7-membered cycloalkyl saturated and unsaturated (cyclopent-2-enyl and phenyl) rings in ω-alicyclic fatty acyl chains on the structure (lipid packing, lipid chain order, and fraction of gauche defects in the chains) and dynamics (lateral lipid diffusion) of a model lipid bilayer. It was found that ω-alicyclic chains in which the ring was saturated reduced lipid condensation and lowered chain order which would be associated with enhanced fluidity. However, this effect was limited. The lateral diffusion of the lipids diminished as the ring size increased. In particular, ω-cyclohexyl and ω-cycloheptyl acyl tails led to a decrease in lipid diffusion. In contrast, ω-alicyclic acyl chains that contain an unsaturated ring promoted membrane fluidity both in terms of changes in membrane structure and lipid diffusion. This may indicate that saturated and unsaturated terminal rings in ω-alicyclic fatty acids fulfill alternative functions within membranes. Overall, the simulations suggest that ω-alicyclic fatty acids in which the terminal ring is saturated might protect the membrane of thermo-acidophilic bacteria from high-temperature and low-pH conditions through a "dynamical barrier" that would limit lipid diffusion and transmembrane diffusion of undesired ions and molecules.

  3. Sum-frequency generation from molecular monolayers using 14 μm radiation from the FELIX free-electron laser

    International Nuclear Information System (INIS)

    Van der Ham, E.W.M.; Vrehen, Q.H.F.; Eliel, E.R.

    1995-01-01

    Sum-frequency generation (SFG) has developed into a widely applied tool for study of surfaces and interfaces where molecules are present. It combines the surface specificity of a second-order nonlinear optical technique with the power of a spectroscopic method, and it can be used under widely varying experimental conditions ranging from UHV to electrochemical cells. The important characteristic of SFG is that it allows one to study the average spatial orientation of a molecular bond in a monolayer of molecules at an interface. Until recently SFG measurements were confined to the frequency interval Y μ > 1700 cm -1 because of a lack of suitable laser sources at wave-lengths λ > 6 μm. So for most molecules only a few vibrational modes and thus intramolecular bonds can be studied. We have developed a universal sum-frequency spectrometer around the FELIX free-electron law that covers the complete molecular fingerprint since we can generate any IR wavelength between 2.75 and 110 fμ at the FELIX facility. We have used this setup for a series of exploratory SFG experiments in a frequency range that was hitherto unexplored in the study of molecular monolayers. We have studied thiol monolayers chemisorbed on a variety of noble metals (Au, Ag, Pt) where we focussed on the C-S stretch vibration at ν = 702 cm -1 (λ = 14.3 μm). We have found spectroscopic features revealing the presence of both the trane and gauche conformers of the adsorbed molecules. The present measurements open a whole new wavelength range for nonlinear optical studies of interfaces

  4. Hybrid inorganic-organic polymer electrolytes: synthesis, FT-Raman studies and conductivity of {l_brace}Zr[(CH{sub 2}CH{sub 2}O){sub 8.7}]{sub {rho}}/(LiClO{sub 4}){sub z}{r_brace}{sub n} network complexes

    Energy Technology Data Exchange (ETDEWEB)

    Di Noto, Vito; Zago, Vanni; Biscazzo, Simone; Vittadello, Michele

    2003-01-15

    This paper describes the synthesis and characterization of three-dimensional hybrid inorganic-organic networks prepared by a polycondensation reaction between Zr(O(CH{sub 2}){sub 3}CH{sub 3}){sub 4} and polyethylene glycol 400 (PEG400). Eleven hybrid networks doped with varying concentrations of LiClO{sub 4} salt were prepared. On the basis of analytical data and FT-Raman studies it was concluded that these polymer electrolytes consist of inorganic-organic networks with zirconium atoms bonded together by PEG400 bridges. These polymers are transparent with a solid rubber consistency and are very stable under inert atmosphere. Scanning electron microscopy revealed a smooth glassy surface. X-ray fluorescence microanalysis with energy dispersive spectroscopy demonstrated that all the constituent elements are homogeneously distributed in the materials. Thermogravimetric measurements revealed that these materials are thermally stable up to 262 deg. C. Differential Scanning Calorimetry measurements indicated that the glass transition temperature T{sub g} of these inorganic-organic hybrids varies from -43 to -15 deg. C with increasing LiClO{sub 4} concentration. FT-Raman investigations revealed the TGT (T=trans, G=gauche) conformation of polyether chains and allowed characterization of the types of ion-ion and ion-polymer host interactions in the bulk materials. The conductivity of the materials at different temperatures was determined by impedance spectroscopy over the 20 Hz-1 MHz frequency range. Results indicated that the materials conduct ionically and that their ionic conductivity is strongly influenced by the segmental motion of the polymer network and the type of ionic species distributed in the bulk material. Finally, it is to be highlighted that the hybrid network with a n{sub Li}/n{sub O} molar ratio of 0.0223 shows a conductivity of ca. 1x10{sup -5} S cm{sup -1} at 40 deg. C.

  5. Crystal and molecular structure of 2-thiouridine

    Energy Technology Data Exchange (ETDEWEB)

    Hawkinson, S W

    1977-01-01

    The ''minor'' nucleoside 2-thiouridine, C/sub 9/H/sub 12/O/sub 5/N/sub 2/S, crystallizes in a monoclinic cell, space group P2/sub 1/ with a = 5.049 (2), b = 7.526 (2), c = 14.050 (3) A, ..beta.. = 90.17 (2)/sup 0/, and d = 1.619 g cm/sup -3/ (for Z = 2) at 22 +- 2/sup 0/C. The structure was derived from 1334 unique intensities measured with an Oak Ridge computer-controlled diffractometer to a limit of sin theta/lambda = 0.65 A/sup -1/ with Nb-filtered Mo K..cap alpha.. radiation. Atomic parameters were obtained by a combination of Patterson and Fourier techniques and refined by full-matrix least squares to a final R(F) value of 0.023 for all data. The bond lengths and angles in the molecule agree well with those of other thiopyrimidines (C(2) - S = 1.677 A). The conformation of the sugar ring relative to the base is anti with a torsion angle chi(O(1')--C(1') ..-->.. N(1)--C(6)) of 17/sup 0/. The sugar exists in the 3'-endo conformation. The O(5')--C(5') bond is gauche to C(4) - O(1') and trans to C(4')--C(3') (torsion angles of 74 and -169/sup 0/ respectively). The molecules are linked together in the crystal by hydrogen bonds in an intricate network which is identical to that inferred by Kojic-Prodic, Liminga, Sljukic and Ruzic-Toros (Acta Cryst. (1974), B30, 1550-1555) for the crystal structure of 5,6-dihydro-2-thiouridine. 2 figures; 6 tables.

  6. Surdité brusque: étude rétrospective à propos de 36 cas

    Science.gov (United States)

    Nadour, Karim; Chihani, Mehdi; Darouassi, Youssef; Touati, Mliha; Moujahid, Mountassir; Ammar, Haddou; Bouaity, Brahim

    2014-01-01

    L'Objectif de cette étude est de rapporter notre expérience concernant la prise en charge des surdités brusques en soulignant la notion d'urgence, et en montrant les facteurs influant la probabilité de récupération. Nous rapportons une étude rétrospective concernant 36 patients colligés au service ORL de l'Hôpital Militaire Avicenne de Marrakech au Maroc, pendant 05 ans. Uniquement les surdités brusques unilatérales ont été incluses dans notre étude. Il s'agit de 21 oreilles droites et 15 gauches. Les données cliniques étaient recueillies par l'interrogatoire et l'examen clinique complet. L’évolution du déficit auditif a été évaluée à l'admission, toutes les 48 heures et après arrêt du traitement par audiométrie tonale liminaire. Tous nos patients ont bénéficié des potentiels évoqués auditifs du tronc cérébral, 09 d'entre eux d'une tomodensitométrie. Une IRM a été réalisée chez une seule patiente. Le protocole thérapeutique comprend des corticostéroïdes, vasodilatateurs. Seulement 16,6% des patients ont récupéré la totalité de la perte auditive initiale. Les potentiels évoqués auditifs (P.E.A) ont décelé un cas de neurinome de l'acoustique confirmé par l'imagerie. PMID:25995795

  7. Organizing centers in parameter space of discontinuous 1D maps. The case of increasing/decreasing branches

    Directory of Open Access Journals (Sweden)

    Sushko Iryna

    2012-08-01

    Full Text Available This work contributes to classify the dynamic behaviors of piecewise smooth systems in which border collision bifurcations characterize the qualitative changes in the dynamics. A central point of our investigation is the intersection of two border collision bifurcation curves in a parameter plane. This problem is also associated with the continuity breaking in a fixed point of a piecewise smooth map. We will relax the hypothesis needed in [4] where it was proved that in the case of an increasing/decreasing contracting functions on the left/right side of a border point, at such a crossing point, we have a big-bang bifurcation, from which infinitely many border collision bifurcation curves are issuing. Cet travail est une contribution à la classification des comportements dynamiques de systèmes réguliers par morceaux dans lesquels les bifurcations de collision au bord caractérisent les changements qualitatifs de la dynamique. Un point central de notre étude est l’intersection de deux courbes de bifurcation de colision au bord dans un plan de paramètre. Ce problème est aussi associé avec la rupture de continuité en un point fixe d’une application régulière par morceaux. Nous allons relacher l’hypothèse requise dans [4], où il a été montré que dans le cas de fonctions contractantes croissantes/décroissantes strictement à gauche/droite d’un point du bord, en un tel point de franchissement, nous avons une bifurcation big-bang, de laquelle est issue une infinité de courbes de bifurcation de collision au bord.

  8. Pasado y presente. Una lectura sobre El encargo del cazador (Joaquin Jordá, 1990 / Past and Present. A Reading about El encargo del cazador (Joaquín Jordá, 1990

    Directory of Open Access Journals (Sweden)

    Juan Caravaca Mompeán

    2016-08-01

    Full Text Available El presente trabajo describe la vinculación que Joaquín Jordá mantuvo con su pasado a través de la película El encargo del cazador; un pasado marcado por su participación en la Escuela de Barcelona, su paso por la Escuela Oficial de Cine (EOC y su militancia política. Para ello, se abordan sus trabajos como realizador, desde los años 60 hasta la filmación de El encargo del cazador, con el objetivo de trazar su evolución como director y el proceso que desarrolló hasta crear un estilo propio que luchará a contracorriente con sus trabajos previos. En segundo lugar, y a través de la figura de Jacinto Esteva, protagonista de El encargo del cazador, se ha descrito la unión especial que existió entre Jordá, la Escuela de Barcelona y la gauche divine. Ambos mantuvieron una amistad durante los años 60 y, tras el fallecimiento de Esteva, Jordá recuperó la memoria de su compañero y la del grupo al que había pertenecido filmando El encargo del cazador. Gracias a este reencuentro con su pasado, Jordá pudo reconstruir la imagen de este grupo y separarse de él, desmitificando aquella Escuela de Barcelona y reedificando, al mismo tiempo, la imagen de Jacinto Esteva a través de la última etapa de su vida. Por último, se han buscado las causas de este cambio atendiendo al contexto cinematográfico en el que apareció la película para evidenciar una transformación en la tendencia documental que se vivía en España, transformación de la que formó parte El encargo del cazador, y que buscó el cambio en la reflexión acerca del cine, su historia y sus procesos.Palabras clave: cine español, documental, Joaquín Jordá, Jacinto Esteva, El encargo del cazador, Escuela de Barcelona. AbstractThis paper explores the links that Joaquín Jordá sustained with his past through the film El encargo del cazador; a past marked by his participation in La Escuela de Barcelona, his time at the city’s Escuela Oficial de Cine (EOC and his political

  9. Facile preparation of an alternating copolymer-based high molecular shape-selective organic phase for reversed-phase liquid chromatography.

    Science.gov (United States)

    Mallik, Abul K; Noguchi, Hiroki; Rahman, Mohammed Mizanur; Takafuji, Makoto; Ihara, Hirotaka

    2018-06-22

    The synthesis of a new alternating copolymer-grafted silica phase is described for the separation of shape-constrained isomers of polycyclic aromatic hydrocarbons (PAHs) and tocopherols in reversed-phase high-performance liquid chromatography (RP-HPLC). Telomerization of the monomers (octadecyl acrylate and N-methylmaleimide) was carried out with a silane coupling agent; 3-mercaptopropyltrimethoxysilane (MPS), and the telomer (T) was grafted onto porous silica surface to prepare the alternating copolymer-grafted silica phase (Sil-alt-T). The new hybrid material was characterized by elemental analyses, diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy, and solid-state 13 C and 29 Si cross-polarization magic-angle spinning (CP/MAS) NMR spectroscopy. The results of 13 C CP/MAS NMR demonstrated that the alkyl chains of the grafted polymers in Sil-alt-T remained disordered, amorphous, and mobile represented by gauche conformational form. Separation abilities and molecular-shape selectivities of the prepared organic phase were evaluated by the separation of PAHs isomers and Standard Reference Material 869b, Column Selectivity Test Mixture for Liquid Chromatography, respectively and compared with commercially available octadecylsilylated silica (ODS) and C 30 columns as well as previously reported alternating copolymer-based column. The effectiveness of this phase is also demonstrated by the separation of tocopherol isomers. Oriented functional groups along the polymer main chains and cavity formations are investigated to be the driving force for better separation with multiple-interactions with the solutes. One of the advantages of the Sil-alt-T phase to that of the previously reported phase is the synthesis of the telomer first and then immobilized onto silica surface. In this case, the telomer was characterized easily with simple spectroscopic techniques and the molecular mass and polydispersity index of the telomer were determined by size exclusion

  10. Métastase pleurale et pulmonaire d’une polyadénofibromatose dégénéréé: à propos d’un cas

    Science.gov (United States)

    El Hachimi, Kawtar; Benjelloun, Hanane; Zaghba, Nahid; Yassine, Najiba

    2017-01-01

    La polyadénofibromatose ou l’adénofibromatose est définie par la présence d’au moins 3 adénofibromes, uni ou bilatéraux atteignant une taille importante responsable de troubles trophiques. Nous rapportons une observation colligée au service des maladies respiratoires du Centre Hospitalier Universitaire Ibn Rochd de Casablanca. Il s’agit d’une patiente âgée de 46ans, suivie depuis l’âge de 30 ans pour une adénofibromatose bilatérale opérée à 4 reprises. Suite à un bilan préopératoire d’une mastectomie bilatérale, une radio du thorax a été réalisée objectivant un hémithorax droit opaque avec refoulement des éléments du médiastin. L’examen clinique retrouvait un syndrome d’épanchement liquidien de l’hémithorax droit et une adénopathie cervicale sus claviculaire gauche. La ponction biopsie pleurale confirmait la localisation pleurale d’un carcinome peu différencié et invasif compatible avec une origine mammaire. La bronchoscopie après évacuation pleurale objectivait un aspect infiltré de tout l’arbre bronchique, dont les biopsies concluaient au même résultat anatomopathologique. Le traitement préconisé était une polychimiothérapie. L’évolution était marquée par l’apparition de métastases hépatiques. A travers cette observation, nous concluons que les adénofibromes nécessitent une surveillance régulière vu le risque de dégénérescence vers le cancer du sein qui est une cause fréquente de métastases pleuropulmonaires. PMID:29515733

  11. Semiconducting perovskites (2-XC6H4C2H4NH3)2SnI4 (X = F, Cl, Br): steric interaction between the organic and inorganic layers.

    Science.gov (United States)

    Xu, Zhengtao; Mitzi, David B; Dimitrakopoulos, Christos D; Maxcy, Karen R

    2003-03-24

    Two new semiconducting hybrid perovskites based on 2-substituted phenethylammonium cations, (2-XC(6)H(4)C(2)H(4)NH(3))(2)SnI(4) (X = Br, Cl), are characterized and compared with the previously reported X = F compound, with a focus on the steric interaction between the organic and inorganic components. The crystal structure of (2-ClC(6)H(4)C(2)H(4)NH(3))(2)SnI(4) is solved in a disordered subcell [C2/m, a = 33.781(7) A, b = 6.178(1) A, c = 6.190(1) A, beta = 90.42(3)(o), and Z = 2]. The structure is similar to the known (2-FC(6)H(4)C(2)H(4)NH(3))(2)SnI(4) structure with regard to both the conformation of the organic cations and the bonding features of the inorganic sheet. The (2-BrC(6)H(4)C(2)H(4)NH(3))(2)SnI(4) system adopts a fully ordered monoclinic cell [P2(1)/c, a = 18.540(2) A, b = 8.3443(7) A, c = 8.7795(7) A, beta = 93.039(1)(o), and Z = 2]. The organic cation adopts the anti conformation, instead of the gauche conformation observed in the X = F and Cl compounds, apparently because of the need to accommodate the additional volume of the bromo group. The steric effect of the bromo group also impacts the perovskite sheet, causing notable distortions, such as a compressed Sn-I-Sn bond angle (148.7(o), as compared with the average values of 153.3 and 154.8(o) for the fluoro and chloro compounds, respectively). The optical absorption features a substantial blue shift (lowest exciton peak: 557 nm, 2.23 eV) relative to the spectra of the fluoro and chloro compounds (588 and 586 nm, respectively). Also presented are transport properties for thin-film field-effect transistors (TFTs) based on spin-coated films of the two hybrid semiconductors.

  12. Doppler transcranien au cours de la drépanocytose chez l'enfant Malagasy

    Science.gov (United States)

    Herinirina, Nicolas Fanantenana; Rajaonarison, Lova Hasina Ny Ony Narindra; Herijoelison, Andry Roussel; Rakoto, Olivat Aimée Alson; Ahmad, Ahmad

    2016-01-01

    Introduction Le doppler transcrânien est un outil efficace permettant de dépister les enfants drépanocytaires à risque d'AVC. Méthodes Nous avons réalisé une étude descriptive transversale sur des enfants Malagasy âgés entre 24 mois et 15 ans (groupe 1: 57 drépanocytaires, groupe 2: 43 témoins) afin d’évaluer le profil vélocimétrique des artères cérébrales chez les drépanocytaires. Un examen Doppler transcrânien a été réalisé avec étude des flux sanguins cérébraux chez les enfants des deux groupes. Résultats Pour les sujets drépanocytaires, la vitesse moyenne (VM) de l'artère cérébrale moyenne était de 100,9 ± 26,8 cm/s, l'indice de pulsatilité (IP) de 0,73 ± 0,20, la différence entre les artères cérébrales moyennes droite et gauche (ACMr) de 19,8 ± 21,5 cm/s, le rapport des vitesses de l'artère cérébrale antérieure/artère cérébrale moyenne (ACA/ACM) de 0,7 ± 0,2. Pour les enfants non drépanocytaires, VM: 80,6 ± 19,3 cm/s, IP: 0,79 ± 0,14, ACMr: 17 ± 20,1 cm/s, ACA/ACM: 0,8 ± 0,2. La vélocité des enfants drépanocytaires était supérieure au groupe contrôle. Les vitesses ont été corrélées avec le taux d'hémoglobine et l’âge et non pas avec le sexe et le volume globulaire moyen. Conclusion Les vitesses circulatoires cérébrales sont élevées chez les drépanocytaires que les enfants non drépanocytaires et sont influencées par le taux d'hémoglobine et l’âge. PMID:27516829

  13. Cancer du sein au Cameroun, profil histo-épidémiologique: à propos de 3044 cas

    Science.gov (United States)

    Engbang, Jean Paul Ndamba; Essome, Henri; Koh, Valère Mve; Simo, Godefroy; Essam, Jean Daniel Sime; Mouelle, Albert Sone; Essame, Jean Louis Oyono

    2015-01-01

    Décrire les caractéristiques épidémiologiques et histo-pathologiques des tumeurs malignes du sein au Cameroun. Il s'agissait d'une étude rétrospective descriptive portant sur les tumeurs malignes du sein, colligées, dans les registres des différents laboratoires d'Anatomie Pathologique publiques et privés repartis dans cinq régions (centre, littoral, Ouest, Nord-ouest, Sud-ouest), pendant une période de 10 ans (2004-2013). Les paramètres étudiés étaient la fréquence, l’âge, le sexe, la localisation, le type et le grade histologique, et les récepteurs hormonaux. Un total de 3044 cas de cancers du sein a été recensé, soit une fréquence annuelle de 304,4 cas en moyenne. Le sexe féminin était le plus représenté avec 2971 cas (97,60%) et les hommes avec 73 cas (2,40%), soit un sexe ratio (H/F) de 0,02. L’âge moyen des patients était de 46±15,87 ans, avec des extrêmes de 13 et 95 ans. Selon la localisation, le sein gauche était atteint dans 1244 cas (52%) et le sein droit dans 1115 cas (47%). Au plan histologique, on retrouvait essentiellement des carcinomes avec 96,50% des cas, des sarcomes 1,39%, des lymphomes 1,07% et la maladie de Paget du mamelon, 1,03%. Les tumeurs épithéliales étaient infiltrantes dans 2049 cas (84,46%), avec une prédominance du carcinome canalaire infiltrant (1870 cas) et non infiltrantes dans 377 cas (15,54%). Le grade histo-pronostic de SBR avait révélé une prédominance du grade II dans 66% des cas. Les cancers du sein restent une pathologie fréquente au Cameroun et atteignent principalement la population féminine en âge de procréer. Ils sont caractérisés par la prédominance du carcinome canalaire infiltrant. PMID:26523182

  14. Etude du strabisme chez des enfants de 0 à 15 ans suivis a Lubumbashi, République Démocratique du Congo: analyse des aspects épidémiologiques et cliniques

    Science.gov (United States)

    Bienvenu, Yogolelo Asani; Angel, Musau Nkola; Sebastien, Mbuyi Musanzayi; Philippe, Cilundika Mulenga; Léon, Kabamba Ngombe; Eugene, Twite Kabange; Chami, Cham Lubamba; Prosper, Kalenga Muenze Kayamba; Claude, Speeg-Schatz; Gaby, Chenge Borasisi

    2015-01-01

    Introduction Le strabisme est défini comme un syndrome à double composante: motrice et sensorielle. Le but de ce travail est de décrire les aspects épidémiologiques et cliniques du strabisme chez l'enfant congolais de 0 à 15 ans dans la ville de Lubumbashi. Méthodes Il s'agit d'une étude descriptive longitudinale sur les aspects épidémiologiques et cliniques du strabisme chez l'enfant congolais de 0 à 15 ans dans la ville de Lubumbashi entre Décembre 2012 à Décembre 2013. Nous avons recueilli l’âge des patients, leur sexe, leur provenance, le type de strabisme, la réfraction, le fond d'oeil, les antécédents (hérédité) ainsi que le type de la déviation strabique observé sur 70 patients. Résultats Nous avons observé 70 cas de strabisme manifeste dont 31 cas (44,28%) étaient dans la tranche d’âge comprise entre 0 et 5 ans. L’âge moyen de nos patients était de 6,7 ans avec une prédominance du sexe féminin, soit 51,42%. Le strabisme était convergent dans 65,71%, divergent dans 30%, et vertical dans 4,28%. Les ésotropies représentaient 65 cas (92,85%), quatre cas (5,71%) avaient un antécédent familial de strabisme au premier degré de parenté, 21 cas (30%) au second degré de parenté, 45 cas (64,28%) n'avaient pas cet antécédent. L'oeil gauche était le plus dominé dans 30% des cas. Les facteurs favorisant le strabisme étaient inconnus dans 54 cas (77,14%). Le strabisme était secondaire à l'hypermétropie chez 32 patients (42,71%). Conclusion La fréquence du strabisme dans la ville de Lubumbashi chez les enfants âgés de 0 à 15 ans est de 0,50%. Comme dans la plupart des études sur le strabisme de l'enfant, c'est l’ésotropie qui est la déviation la plus commune. PMID:26834919

  15. Matrix isolation FT-IR spectroscopy and molecular orbital study of sarcosine methyl ester

    Science.gov (United States)

    Gómez-Zavaglia, A.; Fausto, R.

    2004-02-01

    N-methylglycine methyl ester (sarcosine-Me) has been studied by matrix isolation FT-IR spectroscopy and molecular orbital calculations undertaken at the DFT/B3LYP and MP2 levels of theory with the 6-311++G(d,p) and 6-31++G(d,p) basis set, respectively. Twelve different conformers were located in the potential energy surface of the studied compound, with the ASC conformer being the ground conformational state. This form is analogous to the dimethylglycine methyl ester most stable conformer and is characterized by a NH⋯O intramolecular hydrogen bond; in this form, the ester group assumes the cis configuration and the OC-C-N and Lp-N-C-C (where Lp is the nitrogen lone electron pair) dihedral angles are ca. -17.8 and 171.3°, respectively. The second most stable conformer ( GSC) differs from the ASC conformer essentially in the conformation assumed by the methylamino group, which in this case is gauche ( Lp-N-C-C dihedral angle equal to 79.4°). On the other hand, the third most stable conformer ( AAC) differs from the most stable form in the conformation of the OC-C-N axis (151.4°). These three forms were predicted to differ in energy by less than ca. 5 kJ mol -1 and represent ≈95% of the total conformational population at room temperature. FT-IR spectra were obtained for sarcosine-Me isolated in argon matrices (T=9 K) revealing the presence in the matrices of the three lowest energy conformers predicted by the calculations. The matrices were prepared by deposition of the vapour of the compound using two different nozzle temperatures, 25 and 60 °C. The relative populations of the three conformers trapped in the matrices were found to be consistent with occurrence of conformational cooling during matrix deposition and with a stabilization of the most polar GSC and AAC conformers in the matrices compared to the gas phase. Indeed, like it was previously observed for the methyl ester of dimethylglycine [Phys. Chem. Chem. Phys. 5 (2003) 52] the different

  16. Characterization of beta-turn and Asx-turns mimicry in a model peptide: stabilization via C--H . . . O interaction.

    Science.gov (United States)

    Thakur, A K; Kishore, R

    2006-04-15

    The chemical synthesis and single-crystal X-ray diffraction analysis of a model peptide, Boc-Thr-Thr-NH2 (1) comprised of proteinogenic residues bearing an amphiphilic Cbeta -stereogenic center, has been described. Interestingly, the analysis of its molecular structure revealed the existence of a distinct conformation that mimics a typical beta-turn and Asx-turns, i.e., the two Thr residues occupy the left- and right-corner positions. The main-chain torsion angles of the N- and C-terminal residues i.e., semiextended: phi = -68.9 degrees , psi = 128.6 degrees ; semifolded: phi = -138.1 degrees , psi = 2.5 degrees conformations, respectively, in conjunction with a gauche- disposition of the obligatory C-terminus Thr CgammaH3 group, characterize the occurrence of the newly described beta-turn- and Asx-turns-like topology. The preferred molecular structure is suggested to be stabilized by an effective nonconventional main-chain to side-chain Ci=O . . . H--Cgamma(i+2)-type intraturn hydrogen bond. Noteworthy, the observed topology of the resulting 10-membered hydrogen-bonded ring is essentially similar to the one perceived for a classical beta-turn and the Asx-turns, stabilized by a conventional intraturn hydrogen bond. Considering the signs as well as magnitudes of the backbone torsion angles and the orientation of the central peptide bond, the overall mimicked topology resembles the type II beta-turn or type II Asx-turns. An analysis of Xaa-Thr sequences in high-resolution X-ray elucidated protein structures revealed the novel topology prevalence in functional proteins (unpublished). In view of indubitable structural as well as functional importance of nonconventional interactions in bioorganic and biomacromolecules, we intend to highlight the participation of Thr CgammaH in the creation of a short-range C=O . . . H--Cgamma -type interaction in peptides and proteins. Copyright 2006 Wiley Periodicals, Inc.

  17. a Study of Vibrational Mode Coupling in 2-FLUOROETHANOL and 1,2-DIFLUOROETHANE Using High-Resolution Infrared Spectroscopy.

    Science.gov (United States)

    Mork, Steven Wayne

    High resolution infrared spectroscopy was used to examine intramolecular vibrational interactions in 2 -fluoroethanol (2FE) and 1,2-difluoroethane (DFE). A high resolution infrared spectrophotometer capable of better than 10 MHz spectral resolution was designed and constructed. The excitation source consists of three lasers: an argon-ion pumped dye laser which pumps a color -center laser. The infrared beam from the color-center laser is used to excite sample molecules which are rotationally and vibrationally cooled in a supersonic molecular beam. Rovibrational excitation of the sample molecules is detected by monitoring the kinetic energy of the molecular beam with a bolometer. The high resolution infrared spectrum of 2FE was collected and analyzed over the 2977-2990 cm^ {-1}^ectral region. This region contains the asymmetric CH stretch on the fluorinated carbon. The spectrum revealed extensive perturbations in the rotational fine structure. Analysis of these perturbations has provided a quantitative measure of selective vibrational mode coupling between the C-H stretch and its many neighboring dark vibrational modes. Interestingly, excitation of the C-H stretch is known to induce a photoisomerization reaction between 2FE's Gg^' and Tt conformers. Implications of the role of mode coupling in the reaction mechanism are also addressed. Similarly, the high resolution infrared spectrum of DFE was collected and analyzed over the 2978-2996 cm ^{-1}^ectral region. This region contains the symmetric combination of asymmetric C-H stretches in DFE. Perturbations in the rotational fine structure indicate vibrational mode coupling to a single dark vibrational state. The dark state is split by approximately 19 cm^{-1} due to tunneling between two identical gauche conformers. The coupling mechanism is largely anharmonic with a minor component of B/C-plane Coriolis coupling. Effects of centrifugal distortion along the molecular A-axis are also observed. The coupled vibrational

  18. Consistent force field modeling of matrix isolated molecules. V. Minimum energy path potential to the conformer conversion of 1,2-difluoroethane: Ar 364, ab initio calculation of electric multipole moments and electric polarization contribution to the conversion barrier

    Science.gov (United States)

    Gunde, R.; Ha, T.-K.; Günthard, H. H.

    1990-08-01

    In this paper results of consistent force field modeling (CFF) of the potential function to conversion of the gauche (g) to the trans (t) conformer of 1,2-difluoroethane (DFE) isolated in an argon matrix will be reported. Starting point are locally stable configurations gDFE:Ar 364 (defect GH1) and tDFE:Ar 364 (TH1) obtained in previous work from CFF modeling of a cube shaped Ar 364 fragment containing one DFE molecule in its center. Using the dihedral angle of DFE as an independent parameter the minimum energy path of the conversion process gDFE:Ar 364→tDFE:Ar 364 will be determined by CFF energy minimization. Determination of the minimum energy path is found to require large numbers of energy minimization steps and to lead to a rather complicated motion of the molecule with respect to the crystal fragment. Surprisingly the molecule-matrix interactions lead to a reduction of the g-t barrier by ≈500 cal/mol and to a stabilization of the trans species by ≈500 cal/mol. This finding is a consequence of a delicate interplay of matrix-molecule and matrix-matrix interactions. Calculation of the electric polarization energy (induced dipole-first-order polarization approximation) is based on extended ab initio calculations of dipole and quadrupole moments and a bond polarizability estimate of the first-order polarizability of DFE as a function of the internal rotation angle, on Fourier expansion of multipole components and use of symmetry for reduction of the order of the linear system defining the (self-consistent) induced dipole moments of all Ar atoms. Electric polarization is found to alter the potential function of the conversion process in a profound way: the g-t barrier and the t-g energy difference are increased to ≈3000 cal/mol and to ≈1500 cal/mol respectively (≈2500 and ≈530 cal/mol respectively for free DFE). Further applications of the technique developed in this work to related problems of matrix isolated molecules, e.g., vibrational matrix

  19. De l’ancien au moderne French cultural policy in Greece during the Metaxas dictatorship

    Directory of Open Access Journals (Sweden)

    Mathilde Chèze

    2012-05-01

    Full Text Available L’article qui suit a pour but d’étudier en quoi la deuxième moitié des années 1930 constitue un moment clé dans la présence culturelle française en Grèce. En effet, à cette époque, les situations politiques intérieures grecque et française prennent des directions diamétralement opposées : dictature de « droite » avec Métaxas d’un côté et mise en place de gouvernements de gauche de l’autre avec le Front populaire. Poussée à repenser sa présence face aux divergences idéologiques, la France se trouve alors dans l’obligation de réorganiser sa politique culturelle. C’est dans ces circonstances qu’elle s’engage pour la première fois sur la voie d’une véritable « économie culturelle ». Sans délaisser les piliers traditionnels de son implantation (institutions scolaires, politiques du livre, son intérêt se porte sur des canaux nouveaux de rayonnement tels que le tourisme, le cinéma.The aim of the article is to study how the second part of the Thirties represent a key moment for the cultural presence of France in Greece. Indeed, between 1935 and 1939, political situations in France and Greece are very differents: on one hand right-wing dictatorship with Metaxas and on the other left-wing governments with the Popular Front. Forced to redefine its presence, Paris seems, in order to preserve its positions, to change tack. For the first time, France tries out a new policy which may be defined as cultural economics. Strengthening its former positions (schools, book policy, France starts to focus on new ways of influence such as tourism and cinema.

  20. Les Offices du cinéma scolaire et éducateur à l’épreuve des publics The Educational Cinema Offices and their publics in France between the two World Wars

    Directory of Open Access Journals (Sweden)

    Pascal Laborderie

    2012-04-01

    Full Text Available En France, dans l’entre-deux-guerres, les Offices du cinéma scolaire et éducateur constituèrent un réseau d’enseignement, d’éducation et de propagande par le cinéma. Comment évaluer les effets de ce dispositif ? Tout d’abord, nous considérons les dispositifs mis en œuvre par les Offices comme une réponse à la diversité des publics, enfants ou adultes, hommes ou femmes, des mondes ouvriers ou des classes intermédiaires, des espaces ruraux ou urbains, de métropole ou des colonies. Puis l’intérêt du cinéma en matière d’enseignement devant un public d’enfants est envisagé à partir des discours des enseignants. Enfin cet article aborde la représentation des enseignants concernant la propagande pour adultes. Des discours à la réalité, il est finalement proposé que cette propagande a surtout permis de faire travailler ensemble les animateurs des Offices au moment même où les divers mouvements du centre et de la gauche étaient divisés.In France, between the two World Wars, the Educational Cinema Offices built a network of teaching, education and propaganda using cinema. How can the effects of this network be assessed? First of all, we examine the plans of action implemented by the Educational Cinema Offices as an answer to the multiplicity of the audiences, children and adults, men or women, working and middle classes, from rural or urban places, from mainland France or colonies. Then the interest of cinema as a matter of teaching in front of children is considered from speeches of teachers. Finally, this article tackles the opinion of the teachers on the propaganda for adults. From speeches to reality, we suggest that this propaganda especially made the driving forces of the Offices work together when the various movements of the centre and of the left wings were divided.

  1. Nuclear magnetic resonance study of alkane conformational statistics

    Science.gov (United States)

    Burnell, E. Elliott; Weber, Adrian C. J.; de Lange, Cornelis A.; Meerts, W. Leo; Dong, Ronald Y.

    2011-12-01

    NMR spectra of ethane, propane, and n-butane as solutes in the nematic liquid crystals 4-n-pentyl-4'-cyanobiphenyl (5CB) and Merck ZLI 1132 (1132) are investigated over a wide temperature range. The ratios of dipolar couplings of ethane to propane are constant over the entire temperature range. Assuming that this constancy applies to the butane conformers facilitates the separation of probability from order parameter. This separation allows the investigation of conformational distribution without the need of invoking any model for the anisotropic intermolecular potential. The results give an order matrix that is consistent with that predicted from model potentials that describe the orientational potential in terms of short-range size and shape effects. The isotropic intermolecular potential contribution to the trans-gauche energy difference Etg is found to be temperature dependent with the values and variation in agreement with that found when the same results are analyzed using the chord model for anisotropic interactions [A. C. J. Weber and E. E. Burnell, Chem. Phys. Lett. 506, 196 (2011)]. The fit obtained for 9 spectra in 5CB (63 dipolar couplings) has an RMS difference between experimental and calculated dipolar couplings of 2.7 Hz, while that for the 16 spectra in 1132 (112 couplings) is 6.2 Hz; this excellent fit with nine adjustable parameters suggests that the assumption of equal temperature dependencies of the order parameters for ethane, propane, and each conformer of butane is correct. Also the fit parameters (Etg and the methyl angle increase) obtained for 1132 and 5CB agree. The results indicate that the chord model, which was designed to treat hydrocarbon chains, is indeed the model of choice for these chains. The temperature variation of Etg provides a challenge for theoreticians. Finally, even better fits to the experimental dipolar couplings are obtained when the energy in the Boltzmann factor is used for scaling ethane to butane results. However

  2. Phase transitions in surfactant monolayers

    International Nuclear Information System (INIS)

    Casson, B.D.

    1998-01-01

    Two-dimensional phase transitions have been studied in surfactant monolayers at the air/water interface by sum-frequency spectroscopy and ellipsometry. In equilibrium monolayers of medium-chain alcohols C n H 2n+1 OH (n = 9-14) a transition from a two-dimensional crystalline phase to a liquid was observed at temperatures above the bulk melting point. The small population of gauche defects in the solid phase increased only slightly at the phase transition. A model of the hydrocarbon chains as freely rotating rigid rods allowed the area per molecule and chain tilt in the liquid phase to be determined. The area per molecule, chain tilt and density of the liquid phase all increased with increasing chain length, but for each chain length the density was higher than in a bulk liquid hydrocarbon. In a monolayer of decanol adsorbed at the air/water interface a transition from a two-dimensional liquid to a gas was observed. A clear discontinuity in the coefficient of ellipticity as a function of temperature showed that the transition is first-order. This result suggests that liquid-gas phase transitions in surfactant monolayers may be more widespread than once thought. A solid-liquid phase transition has also been studied in mixed monolayers of dodecanol with an anionic surfactant (sodium dodecyl sulphate) and with a homologous series of cationic surfactants (alkyltrimethylammonium bromides: C n TABs, n = 12, 14, 16). The composition and structure of the mixed monolayers was studied above and below the phase transition. At low temperatures the mixed monolayers were as densely packed as a monolayer of pure dodecanol in its solid phase. At a fixed temperature the monolayers under-went a first-order phase transition to form a phase that was less dense and more conformationally disordered. The proportion of ionic surfactant in the mixed monolayer was greatest in the high temperature phase. As the chain length of the C n TAB increased the number of conformational defects

  3. Structural characterization and mutational assessment of podocin - a novel drug target to nephrotic syndrome - an in silico approach.

    Science.gov (United States)

    Tabassum, Asra; Rajeshwari, Tadigadapa; Soni, Nidhi; Raju, D S B; Yadav, Mukesh; Nayarisseri, Anuraj; Jahan, Parveen

    2014-03-01

    Non-synonymous single nucleotide changes (nSNC) are coding variants that introduce amino acid changes in their corresponding proteins. They can affect protein function; they are believed to have the largest impact on human health compared with SNCs in other regions of the genome. Such a sequence alteration directly affects their structural stability through conformational changes. Presence of these conformational changes near catalytic site or active site may alter protein function and as a consequence receptor-ligand complex interactions. The present investigation includes assessment of human podocin mutations (G92C, P118L, R138Q, and D160G) on its structure. Podocin is an important glomerular integral membrane protein thought to play a key role in steroid resistant nephrotic syndrome. Podocin has a hairpin like structure with 383 amino acids, it is an integral protein homologous to stomatin, and acts as a molecular link in a stretch-sensitive system. We modeled 3D structure of podocin by means of Modeller and validated via PROCHECK to get a Ramachandran plot (88.5% in most favored region), main chain, side chain, bad contacts, gauche and pooled standard deviation. Further, a protein engineering tool Triton was used to induce mutagenesis corresponding to four variants G92C, P118L, R138Q and D160G in the wild type. Perusal of energies of wild and mutated type of podocin structures confirmed that mutated structures were thermodynamically more stable than wild type and therefore biological events favored synthesis of mutated forms of podocin than wild type. As a conclusive part, two mutations G92C (-8179.272 kJ/mol) and P118L (-8136.685 kJ/mol) are more stable and probable to take place in podocin structure over wild podocin structure (-8105.622 kJ/mol). Though there is lesser difference in mutated and wild type (approximately, 74 and 35 kJ/mol), it may play a crucial role in deciding why mutations are favored and occur at the genetic level.

  4. Amine terminated SAMs: Investigating why oxygen is present in these films

    International Nuclear Information System (INIS)

    Baio, J.E.; Weidner, T.; Brison, J.; Graham, D.J.; Gamble, Lara J.; Castner, David G.

    2009-01-01

    Self-assembled monolayers (SAMs) on gold prepared from amine-terminated alkanethiols have long been employed as model positively charged surfaces. Yet in previous studies significant amounts of unexpected oxygen containing species are always detected in amine terminated SAMs. Thus, the goal of this investigation was to determine the source of these oxygen species and minimize their presence in the SAM. The surface composition, structure, and order of amine-terminated SAMs on Au were characterized by X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectroscopy (ToF-SIMS), sum frequency generation (SFG) and near edge X-ray absorption fine structure (NEXAFS) spectroscopy. XPS determined compositions of amine-terminated SAMs in the current study exhibited oxygen concentrations of 2.4 ± 0.4 atomic %, a substantially lower amount of oxygen than reported in previously published studies. High-resolution XPS results from the S 2p , C 1s and N 1s regions did not detect any oxidized species. Angle-resolved XPS indicated that the small amount of oxygen detected was located at or near the amine head group. Small amounts of oxidized nitrogen, carbon and sulfur secondary ions, as well as ions attributed to water, were detected in the ToF-SIMS data due to the higher sensitivity of ToF-SIMS. The lack of N-O, S-O, and C-O stretches in the SFG spectra are consistent with the XPS and ToF-SIMS results and together show that oxidation of the amine-terminated thiols alone can only account for, at most, a small fraction of the oxygen detected by XPS. Both the SFG and angle-dependent NEXAFS indicated the presence of gauche defects in the amine SAMs. However, the SFG spectral features near 2865 cm -1 , assigned to the stretch of the methylene group next to the terminal amine unit, demonstrate the SAM is reasonably ordered. The SFG results also show another broad feature near 3200 cm -1 related to hydrogen-bonded water. From this multi-technique investigation it is

  5. Les kystes hydatiques du foie rompus dans les voies biliaires: à propos de 120 cas

    Science.gov (United States)

    Moujahid, Mountassir; Tajdine, Mohamed Tarik

    2011-01-01

    Etude rétrospective rapportant une série de kystes hydatiques rompus dans les voies biliaires colligés dans le service de chirurgie de l'hôpital militaire Avicenne à Marrakech. Entre 1990 à 2008, sur 536 kystes hydatiques du foie opérés dans le service, 120 étaient compliqués de rupture dans les voies biliaires soit 22,38%. Il y avait 82hommes et 38 femmes. L’âge moyen était de 35 ans avec des extrêmes allant de 10 à 60 ans. La clinique était dominée par la crise d'angiocholite ou une douleur du flanc droit. L'ictère était isolé dans huit cas. La fistule biliokystique était latente dans plus de 50% des cas. Le traitement a consisté en une résection du dôme saillant dans103cas (85,84%), une périkystectomie chez 11 malades (9,16%) et une lobectomie gauche dans six cas (5%). Le traitement de la fistule bilio kystique a consisté en une suture chez 36malades et un drainage bipolaire dans 25 cas, La déconnexion kysto-biliaire ou cholédocotomie trans hépatico kystique selon Perdomo était pratiquée dans 49cas et une anastomose bilio-digestive cholédoco-duodénale dans 10 cas. La durée moyenne d'hospitalisation était de 20jours. Nous déplorons deux décès par choc septique et un troisième par encéphalopathie secondaire à une cirrhose biliaire. La morbidité était représentée par huit abcès sous phrénique, douze fistules biliaires prolongées et deux occlusions intestinales. Les kystes hydatiques rompus dans les voies biliaires représentent la complication la plus grave de cette pathologie bénigne. Le traitement repose sur des méthodes radicales qui sont d'une efficacité reconnue, mais de réalisation dangereuse et les méthodes conservatrices, en particulier la déconnexion kysto-biliaire qui est une méthode simple et qui donne de bons résultats à court et à long terme. PMID:22384289

  6. Free radicals in an Adamantane matrix. XI. Electron paramagnetic resonance study of conformations in the β-halo-tert-butyl radicals

    International Nuclear Information System (INIS)

    Lloyd, R.V.; Wood, D.E.

    1975-01-01

    The β-halo-tert-butyl radicals were prepared by x-irradiation of the corresponding isobutyl halides in an adamantane matrix at 77 0 K and their conformations were determined by analysis of their EPR spectra. The radicals are nonplanar at the radical site, the fluoro and chloro radicals trans eclipsed and the bromo and iodo radicals gauche staggered with respect to the relative orientation of the carbon halogen bond and the direction of the singly occupied orbital. Vibration-rotation motions about the favored conformation are much larger for the fluoro radical than for the others. The rate of interconversion of the inequivalent methylene protons is approximately 1.5 x 10 9 sec -1 for the bromo radical at 202 0 K while it is too slow to measure for the iodo radical at the same temperature. The barrier to interconversion has a lower limit of 3 kcal/mol for the bromo radical and higher than that for the iodo radical. The halogen and proton hfsc in gauss and the g values for the XCH 2 C(CH 3 ) 2 radicals are: 19 F = 103.7, CH 2 = 10.4, CH 3 = 23.3, g = 2.0030 at 214 K; 35 Cl = 19.5, CH 2 = 6.3, CH 3 = 21.1, g = 2.0042 at 215 K; 81 Br = 6.7, CH 2 = 21.4, 42.7, CH 3 = 21.4, g = 2.0010 at 202 K; 127 I = 7.0, CH 2 = 21.9, 43.8, CH 3 = 21.9, g = 2.0009 at 208 K. The fluoro radical decays to nonradical products above 318 0 K, the chloro radical converts to 2-methyl allyl radical above 306 0 K, the bromo radical converts to tert-butyl radical by exchange with a matrix proton (or deuteron) at 209 0 K as does the iodo radical above 225 0 K. Photolysis with a Xe lamp converts the bromo and iodo radicals to nonradical products in less than the experimental time constant of 0.3 sec. The hypothesis is put forward that the nonplanarity and high barrier to rotation observed explain the retention of stereochemical configuration in reactions involving β-chloro, β-bromo, and β-iodo alkyl radicals. (auth)

  7. « Yémen nouveau, futur meilleur » ? “New Yemen and a brighter future ?” Getting back to the 2006 presidential election

    Directory of Open Access Journals (Sweden)

    Marine Poirier

    2008-04-01

    Full Text Available Si l’élection présidentielle du 20 septembre 2006 reconduit ‘Alî ‘Abd Allâh /Sâli/h au sommet de l’ état avec 77% des voix, elle ne marque pas moins une transformation majeure de la scène politique yéménite. Pour la première fois, le président est mis en situation de compétition électorale par une opposition qui, en se réunissant autour d’un candidat unique, parvient à transcender le clivage opposant traditionnellement les partisans de la gauche aux formations islamistes. Cependant, la rénovation de l’enjeu électoral n’éloigne pas significativement le Yémen de la « norme institutionnelle arabe », le régime s’assurant du verrouillage autoritaire du scrutin. Quel est donc l’effet « élection 2006 » ? Dans quelle mesure le jeu politique a-t-il été durablement remodelé par l’introduction de la concurrence ? En offrant des horizons pluralistes sans toutefois contrarier les dynamiques de personnalisation du pouvoir, l’élection n’a-t-elle pas favorisé l’essor de nouvelles formes de contestation politique ?If the presidential election of September 2006 confirmed ‘Alî ‘Abd Allâh /Sâli/h at the head of the State with 77% of the votes, it nonetheless represents a major transformation of Yemeni political scene. For the first time, the president was confronted to electoral contest, as the opposition, gathered around a unique candidate, succeeded in surpassing the traditional leftist - islamist antagonism. However, the renewal of the electoral stake has not really averted Yemen from the “Arab institutional norm”, the regime ensuring an authoritarian lock of the poll. What is, then, the “2006 election” effect? To which extent has the political game been durably remodelled? By offering pluralist prospects without challenging the dynamics of personalization of power, hasn’t the election encouraged the rise of new forms of political contestation?

  8. Critical Survey of the Analysis of Microscopic Distribution of some Bone-Seeking Radionuclides and Assessment of Absorbed Dose; Analyse de la Distribution Microscopique de Radionucleides Osteophiles et Determination de la Dose Absorbee; Kriticheskij obzor dannykh analiza mikroskopicheskogo raspredeleniya otkladyvayushchikhsya v kostyakh radioizotopov i opredelenie pogloshchennoj dozy; Estudio Critico de la Distribucion Microscopica de Algunos Radionuclidos Osteofilos y Evaluacion de la Dosis Absorbida

    Energy Technology Data Exchange (ETDEWEB)

    Jee, W. S.S.

    1964-10-15

    des rayonnements emis par le plutonium depose en surface sur les diverses parties de la zone distale du femur sont les suivants: trabecule metaphysaire, 3; periode interne, 2,6; trabecule epiphysaire, 1,5; canaux de Havers, 1,2; perioste externe, 1. Le depot en surface maximum localise pour les trabecules des vertebres est 35 a 66 fois plus important que la moyenne calculee de debit de dose du a la retention dans le corps. Les auteurs discutent les modifications de la localisation initiale non uniforme du radium et du plutonium en fonction du temps dans leurs rapports avec la nature du remodelage cellulaire de l'os et avec la perte du radionucleide par echange a long terme. Enfin, dans un exemple avec des mesures de la dose de rayonnements locale du plutonium et du radium, faites compte tenu du volume des cellules irradiees, la retention du corps et l'incidence des tumeurs sont mises en correlation et utilisees pour obtenir une toxicite relative du plutonium par rapport au radium et demontrer la valeur d'une certaine connaissance de la distribution microscopique des doses de rayonnements. (author) [Spanish] Los estudios detallados sobre la distribucion microscopica de la dosis proporcionan informacion sobre la distribucion no uniforme de las radiaciones, a diferencia de la distribucion supuesta uniforme, que se deduce de los datos relativos a la retencion en todo el organismo. En ausencia de cierto conocimiento de la distribucion microscopica de la dosis, tanto en el espacio como en el tiempo, se corre el riesgo, al tratar de acopiar datos comparativos sobre la toxicidad, de llegar a deducciones erroneas y pasar por alto conclusiones importantes. A causa de la complejidad del problema, los datos publicados sobre la medicion de la distribucion microscopica de la dosis de irradiacion son muy escasos. Las tecnicas actuales recurren a la autorradiografia y son muy laboriosas. Exigen el recuento de trazas y trabajos de micro- densitometria. La determinacion de la

  9. Les territoires de l´agrobusiness au Brésil Os territórios do agronegócio no Brasil The territories of agrobusiness in Brazil

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    Denise Elias

    2012-06-01

    Full Text Available Les transformations qui se sont produites dans l’activité agricole brésilienne lors de ces quatre dernières décennies, ont eu un impact profond sur la réorganisation du territoire brésilien, donnant lieu à de nouveaux arrangements territoriaux. L’objectif principal de ce texte est de soumettre au débat quelques aspects sur les nouvelles formes d’utilisation et d’organisation du territoire brésilien à partir des processus de diffusion de l’agrobusiness mondialisé. Dans la thèse défendue, on montre qu’au Brésil une partie significative des transformations à la campagne, dans les cinq dernières décennies, est due à la restructuration productive de l’agropastoral - comprise comme une exacerbation du mode capitaliste de produire dans le secteur - et à l’organisation des réseaux agroindustriels, des promoteurs de transformations dans les éléments techniques et sociaux de la structure agraire. En quelques décennies, le pays passe d’un pays éminemment agraire à une des dix économies mondiale. Les réflexes dans la production, dans la société et dans l’espace sont nombreux et complexes. De cette manière, les facteurs de localisation classiques sont redimensionnés, donnant de nouvelles possibilités à la production et, par conséquent, une vraie dispersion spatiale de la production et une réorganisation du territoire. Parmi les principaux vecteurs de cette réorganisation nous aurions la diffusion de l’agrobusiness mondialisé. Tout ceci engendre un attisement de la division territoriale du travail ; une nouvelle distribution des fonctions productives ; une nouvelle géographique économique qui culminent dans un remodelage du territoire et dans de nouveaux découpages spatiaux pour les études géographique. Un de ces découpages spatiaux est totalement pertinent pour analyser l’émergence de nouveaux arrangements territoriaux productifs résultant des dynamiques socio-spatiales inhérentes à la

  10. Considérations ontogénétiques et phylogénétiques concernant l’origine de la parole Ontogenetic and phylogenetic considerations concerning the origin of speech

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    Jean Granat

    2011-10-01

    ces questions ne trouveront pas de solution. Actuellement, il est quand même possible de répondre à la question suivante : si nous supposons que nos ancêtres (et cousins lointains contrôlaient leur larynx et leur conduit vocal de la même manière que les Hommes actuels, est-ce que la géométrie de leur conduit leur permettaient de produire les structures sonores qui sont pratiquement présentes dans toutes les langues du monde ?Nous présenterons ensuite nos travaux qui participent à la nouvelle réarticulation avec une approche véritablement axée sur la pluridisciplinarité. Ils s’inscrivent dans le domaine des relations entre la morphologie des organes de la production de la parole et son contrôle. Nous présentons de nouveaux résultats concernant la croissance du conduit vocal de la naissance à l’âge adulte puis des reconstructions du conduit vocal pour des fossiles qui couvrent la période de 10.000 ans à un million et demi d’années BP (Before Present. À partir du crâne, de la mandibule et des vertèbres cervicales nous essaierons de manière plausible (1 de localiser l’os hyoïde, support de la langue, et la position de la glotte, (2 de reconstituer un conduit vocal, à l’aide d’un modèle articulatoire, (3 d’induire les possibilités acoustiques de tous ces conduits. En combinant phylogenèse et ontogenèse il est possible de représenter l’anatomie du tractus en synthétisant deux remodelages qui renvoient à l’ontogenèse et à la phylogenèse. Nous montrerons que tous ces conduits ont les mêmes potentialités acoustiques, ils peuvent produire les voyelles /i a u/ qui sont pratiquement présentes dans toutes les langues du monde : un triangle à l’intérieur duquel se situent toutes les autres voyelles. Quand aux consonnes les plus fréquentes /p t k/, /b d g/ elles sont aussi à la portée de tous ces conduits vocaux à partir de gestes de fermeture dans des régions précises (lèvres, zone alvéodentale, zone v

  11. Integração e desenvolvimento no Mercosul: divergências e convergências nas políticas econômicas nos governos Lula e Kirchner Intégration et développement dans le Mercosur: divergences et convergences dans les politiques économiques sous les gouvernements Lula et Kirchner Integration and development in Mercosul: divergences and convergences in Lula and Kirchner government economic policies

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    Javier A. Vadell

    2009-06-01

    Full Text Available O início do século XXI é testemunha da ascensão ao poder de novos governos de esquerda e centro-esquerda na América do Sul, que apresentam pelo menos duas características em comum: o questionamento das políticas e reformas pró-mercado ocorridas na década anterior e a volta do Estado como ator central da vida econômica. A despeito desse ponto em comum, uma análise mais aprofundada nos permite perceber certa heterogeneidade de natureza programática e organizacional dos novos governos progressistas. Nesse sentido, propomos analisar as respostas dadas por Argentina e Brasil à crise do neoliberalismo, dando especial ênfase às políticas econômicas para o desenvolvimento e suas implicações para a integração regional. Esta análise mais sistemática permite-nos perceber que a Argentina e o Brasil têm feito escolhas distintas no que diz respeito ao tipo de política adotada. O Brasil tem recorrido a práticas mais ortodoxas, como políticas monetárias restritivas para conter as expectativas de inflação, enquanto a Argentina tem preferido medidas heterodoxas, como controle de preços e restrição às exportações, bem como outras políticas de incentivo ao consumo. Em certa medida, a diferença entre as escolhas pode ser atribuída à própria trajetória econômica e política de ambos os países: as reformas pró-mercado, por exemplo, foram mais intensas na Argentina do que no Brasil, o que implicou, no que diz respeito à estrutura produtiva, uma maior desindustrialização e a extinção de algumas instituições desenvolvimentistas.Le début du XXIème siècle est témoin de l'ascension au pouvoir de nouveaux gouvernements de gauche et de centre-gauche en Amérique du sud, qui ont au moins deux caractéristiques en commum : la mise en question des politiques et réformes favorables au marché survenues dans les annéesprécédentes et le retour de l'État en acteur central de la vie économique. En dépit de ce point commum

  12. La presse italienne, le pouvoir politique et l’autorité judiciaire durant le fascisme

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    Yannick Beaulieu

    2004-09-01

    Full Text Available La presse en Italie constitue un enjeu politique très important dès la fin de la première guerre mondiale. Elle répercute et parfois crée les évolutions politiques qui traversent la société, jusqu’à l’instauration effective de la dictature fasciste. Les différents journaux politiques s’affrontent par articles interposés, puis les journaux de gauche sont les victimes d’incendies et de violences. La place de la magistrature est cruciale dans ce contexte d’agitation permanente, néanmoins il apparaît qu’elle a failli à sa mission de restauration de l’ordre public et d’impartialité. Les rapports entre les magistrats et la presse sont d’ailleurs ambigus. Les partis de gauche perçoivent la magistrature comme un allié objectif de la bourgeoisie et du pouvoir politique, alors que les fascistes lancent parfois des cabales à l’encontre de certains magistrats jugés trop sévères avec les leurs, laxistes avec leurs opposants. L’affaire Giacomo Matteotti marque une rupture radicale, puisque de cette crise Benito Mussolini sort finalement renforcé et engage l’Italie sur la voie totalitaire : interdiction de toute presse qui s’oppose à son dessein et contrôle strict des seuls journaux fascistes autorisés. Les informations judiciaires ne sont plus diffusées et, peu à peu, la propagande s’ajoute au contrôle de la population.La prensa en Italia desempeñó un papel fundamental à partir del final de la Primera Guerra Mundial. Repercutió y a veces orientó las evoluciones políticas de la sociedad, hasta la instauración efectiva de la dictadura fascista. Los diferentes periódicos se enfrentaron y la prensa de izquierda fue a menudo víctima de incendios y de violencias. En este contexto de agitación permanente, el papel de la magistratura fue decisivo. Sin embargo, no cumplió con su misión al no restaurar el orden público y la imparcialidad. Las relaciones entre la magistratura y la prensa fueron

  13. L'Utopie comme esquisse d'un avenir meilleur

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    Hervé Ondoua

    2012-12-01

    Full Text Available Le postmodernisme se donne explicitement comme une philosophie de la mondialisation. En occident, Jacques Derrida, par sa déconstruction, est l’un des penseurs qui anime le débat postmoderne en considérant que notre ère manque la fin de rationalité, du progrès et de la recherche d’un sens. La déconstruction se définit comme l’ensemble des techniques et stratégies utilisées par Derrida pour démonter, fissurer et déplacer toute logique universelle. Par le mécanisme de la différance, l’homme sort de tout cadre originaire (grands ensembles, méta récits, seul demeure la trace. L’homme pris dans la trace marque son refus de solidarité avec tout centre, tout principe, toute origine, etc. Cette idée est radicalisée par le légiste, personnage emblématique dans l���Utopie de Thomas More. En effet, le légiste fait l’éloge de la justice sévère anglaise. Partant de la théorie socio-biologiste selon laquelle les comportements sociaux sont génétiques, le légiste dans l’Utopie de More soutient qu’il faut une justice sévère, inflexible, rigide pour nettoyer la cité de ces maux. Dans ce sens, il faut condamner autant d’individus à la potence, car les maux sociaux sont naturels et innées. C’est contre cette approche néolibérale que s’insurge Thomas More. Tout comme les mouvements de gauches, l’Utopie de More explique les maux sociaux par les injustices sociales, la démission de la société, et surtout le manque de l’éducation. Du coup, avec l’Utopie, il s’agit de relativiser le monde dans lequel nous vivons : un autre monde est possible que celui dans lequel nous vivons. Partant delà, l’utopie notamment celle de Francis Bacon ou Thomas More, n’est-elle pas un genre littéraire altermondialiste ? Si la logique néolibérale impose son diktat et pose le principe selon lequel il n’y a pas d’alternative autre que ce que nous offre le capitalisme, ne faut-il pas voir dans l’Utopie, un

  14. Le traumatisme du colon: l'expérience du CHU Hassan II de Fès

    Science.gov (United States)

    Benjelloun, El Bachir; Hafid, Hasnai; Karim, Ibnmajdoub; Ousadden, Abdelmalek; Mazaz, Khalid; Taleb, Kahlid Ait

    2012-01-01

    Introduction Les traumatismes du colon sont associés à un risque majeur de complications septiques et de mortalité. Le but de notre étude est d’évaluer les circonstances, la prise en charge, le suivi et les facteurs pronostic de morbidité postopératoire des malades victimes d'un traumatisme colique. Méthodes Il s'agit d'une étude rétrospective sur une série de 49 patients opérés pour des plaies coliques aux services de chirurgie viscérale du CHU HASSAN II de Fès sur une période de 8 ans de juillet 2003 à juillet 2011. Résultats L’âge moyen de nos patients était de 25ans (16-70) avec une nette prédominance masculine (93.8%). Les plaies coliques secondaires à un traumatisme par arme blanche représentent 85% des cas (42 patients), suivi par les plaies iatrogènes au cours d'une coloscopie chez 6 patients (13%), puis les contusions abdominales chez 1 patient (2%). Les parties du cadre colique les plus touchées étaient le colon transverse chez 19 patients (38%) et le colon descendant chez 12 patients (24, 5%). Le colon sigmoïde était le segment le plus touché au cours d'une coloscopie4/6. Quarante-deux patients (85%) ont eu une suture primaire des plaies coliques, six patients (13%) une diversion fécale et un patient (2%) une résection-anastomose. Deux patients (4%) sont décédés suite à un choc septique. La morbidité globale était de 38,7% dominé essentiellement par l'infection de la paroi chez 14 patients et une péritonite post opératoire chez 3 patients. L'analyse univarié a montré une différence significatif en terme d'infection de la paroi entre le groupe colostomie versus suture simple (50% vs 20,9% p<0,05). L'atteinte du colon gauche et la réalisation d'une colostomie sont associés à un risque plus élevés de complications postopératoires. Conclusion La suture primaire peut être effectuée avec un faible taux de complications postopératoire chez la majorité des patients suite à un traumatisme du colon. PMID

  15. La déclaration de repentir dans la Grèce des années 1940

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    Christina Alexopoulos

    2011-11-01

    Full Text Available La déclaration de repentir ou la première arme idéologique anticommuniste des gouvernements grecs qui détruisait moralement à jamais le suspect et sa famille.L’article situe d’abord le contexte historique de la déclaration de repentir, arme de propagande et expression de l’anticommunisme, largement employée par les régimes grecs avant, pendant et après la guerre civile. Il étudie le discours de la déclaration, ses soubassements idéologiques, son fonctionnement, son impact sur la subjectivité des signataires ainsi que son incidence sur la vie politique et sociale. Il analyse les textes de loi successifs qui refusent aux prisonniers politiques la reconnaissance de leur statut et institutionnalisent la déclaration de repentir comme seule alternative à l’emprisonnement et à la déportation. Les prisonniers doivent choisir entre la persévérance dans leur « erreur idéologique » et le rejet de leur action politique ou militaire contre l’occupant nazi, les milices collaborationnistes et l’armée gouvernementale. Il analyse comment la déclaration détruit moralement le prisonnier, lui enlève son identité, son visage social, un pan entier de son histoire et surtout sa dignité, et comment elle peut entraîner une transformation complète du signataire, contraint d’adopter l’idéologie de ses ennemis. Enfin, la propagande gouvernementale sur ces déclarations scelle l’exclusion de la gauche du paysage politique du pays.The article first situates the historical context of the declaration of repentance, weapon of propaganda and expression of anti-communism, largely employed by the Greek regimes before, during and after the Greek civil war. It studies the discourse of the declaration, its ideological foundations, its functioning, its impact on the subjectivity of the signatories as well as its impact on political and social life. It analyses the successive legal texts that denied political prisoners the recognition

  16. Bis(μ-benzoato-κ2O:O′bis(benzoato-κOoctabutyldi-μ3-oxido-tetratin(IV

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    Hans Reuter

    2017-03-01

    Full Text Available The asymmetric unit of the title compound, [{Sn(C4H92(C6H5COO}2O]2, consists of two half molecules, completed by application of inversion symmetry. Both molecules adopt a ladder structure typical for this class of dimeric tetraorganodistannoxane dicarboxylates characterized by a centrosymmetric four-membered (Sn—O2 ring of rhomboidal shape that is extended on both sides by folded six-membered Sn—O—C rings. To a first approximation, both kinds of Sn atoms (Sni and Sno are trigonal–bipyramidally coordinated. The bond angles between the n-butyl groups are widened [135.64 (7–146.20 (7°] in comparison with an ideal trigonal bipyramid. Sn—O bond lengths within the {R2SnO3} coordination sphere depend strongly on the position of the corresponding O atom – axial (ax or equatorial (eq – as well as on the functionality of the carboxylate groups which exhibit μ2 (–COOi and μ1 (–COOo coordination modes, respectively. In summary, the following sequence of distances [mean values] is found: d(Sno—Oμ3eq [2.024 (2 Å] < d(Sni—Oμ3eq [2.044 (2 Å] < d(Sni—Oμ3ax [2.158 (6 Å] < d(Sno—Oμ1-carbax [2.182 (6 Å] < d(Sni—Oμ2-carbax [2.250 (2 Å] ≃ d(Sno—Oμ2-carbax [2.247 (12 Å]. The n-butyl groups adopt an anti–anti conformation with exception of two disordered outer n-butyl groups of the second molecule which exhibit gauche–anti and anti–gauche conformations. Weak intramolecular Sn...O interactions between the different O atoms of the outer carboxyl groups with the inner, as well as outer, Sn atoms give rise to a strongly distorted octahedral coordination at these Sn atoms. Intermolecular interactions between the individual molecules are restricted to van der Waals and O...H—C interactions of which a nearly linear very short C—H...O contact between the H atom of the phenyl group of one of the molecules with the outer non-coordinating C=O group of the other molecule is the most prominent

  17. Élections présidentielles 2011 au Pérou : le retour inattendu du débat politique

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    Alexis Sierra

    2012-03-01

    Full Text Available L’élection à la Présidence de la République du Pérou du candidat nationaliste « de gauche » Ollanta Humala, en juin 2011, a constitué une surprise pour les observateurs. Dans un contexte de forte croissance économique et de diminution de la pauvreté, les électeurs semblaient devoir privilégier la continuité. La cartographie des votes à deux échelles (celle des régions et celle des districts de la capitale, Lima aide à comprendre comment les stratégies menées par les différents partis et alliances ont abouti à porter au second tour les deux candidats qui provoquaient initialement le plus fort rejet dans la plus grande partie de l’électorat, Ollanta Humala, et Keiko Fujimori. Ollanta Humala a alors réussi à rassembler, au second tour, tant le vote des intellectuels et artistes qui s’étaient opposées à la dictature de Alberto Fujimori, que celui des laissés pour compte du développement néolibéral.The election to the Presidency of Peru of the nationalist and “leftist” candidate Ollanta Humala, in June, 2011, surprised most observers. In a context of strong economic growth and poverty decrease, voters seemed to have to opt for continuity. The mapping of the votes at the regional scale, and at the district scale in the capital Lima, helps to understand how the strategies followed by the various parties and coalitions took to the second round the two candidates that elicited the strongest rejection from the electorate, Ollanta Humala and Keiko Fujimori. Ollanta Humala obtained in the second round the support of both intellectuals and artists that had opposed the dictatorship of Alberto Fujimori, as well as the votes of those who have been left behind by the neoliberal path to development.La elección a la Presidencia del Perú del candidato nacionalista “de izquierda” Ollanta Humala, en junio del 2011, ha constituido una sorpresa para los observadores. En un contexto de fuerte crecimiento económico y de

  18. Blood pressure reactivity to mental stress is attenuated following resistance exercise in older hypertensive women

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    Gauche R

    2017-05-01

    Full Text Available Rafael Gauche,1 Ricardo M Lima,1,2 Jonathan Myers,2 André B Gadelha,1 Silvia GR Neri,1 Claudia LM Forjaz,3 Lauro C Vianna1 1Faculty of Physical Education, University of Brasília, Brasília, Brazil; 2Cardiology Division, Veterans Affairs Palo Alto Health Care System and Stanford University, Palo Alto, CA, USA; 3School of Physical Education and Sport, University of São Paulo, São Paulo, Brazil Purpose: This study aimed to investigate the effects of resistance exercise (RE on autonomic control and blood pressure (BP reactivity during mental stress (MS in treated older hypertensive women. Methods: Ten older hypertensive women (age =71.1±5.5 years; body mass index =24.2±3.9; mean BP [MBP] =85.4±3.5 underwent a protocol consisting of BP and heart rate variability (HRV output assessments at baseline and during MS, and these measurements were taken before and 60 minutes after two bouts of RE (traditional and circuit. MS was induced through a computerized 3-minute Stroop color–word test before and 1 hour after each exercise session; BP was measured every minute during MS, and HRV was monitored as a measure of cardiac autonomic control. Results: A significant effect of time on systolic BP (∆pre =17.4±12.8 versus ∆post =12.5±9.6; P=0.01, diastolic BP (∆pre =13.7±7.1 versus ∆post =8.8±4.5; P=0.01, and MBP (∆pre =14.0±7.7 versus ∆post =9.3±5.4; P<0.01 after RE was observed, with no differences between the two sessions. In addition, a significant effect of time on log-normalized low-frequency component of HRV (ms2; 5.3±0.8 pre-exercise MS versus 4.8±1.0 baseline value; P=0.023 was also observed, showing a significant change from baseline to MS before RE, but not after RE sessions. These results may be related to a lessened RE-mediated cardiac sympathetic activity during MS. Conclusion: RE is an effective tool to reduce BP reactivity to MS, which could therefore be associated with an acute reduction in cardiovascular risk. This

  19. Atomic-Resolution Transmission Electron Microscopic Movies for Study of Organic Molecules, Assemblies, and Reactions: The First 10 Years of Development.

    Science.gov (United States)

    Nakamura, Eiichi

    2017-06-20

    A molecule is a quantum mechanical entity. "Watching motions and reactions of a molecule with our eyes" has therefore been a dream of chemists for a century. This dream has come true with the aid of the movies of atomic-resolution transmission electron microscopic (AR-TEM) molecular images through real-time observation of dynamic motions of single organic molecules (denoted hereafter as single-molecule atomic-resolution real-time (SMART) TEM imaging). Since 2007, we have reported movies of a variety of single organic molecules, organometallic molecules, and their assemblies, which are rotating, stretching, and reacting. Like movies in the theater, the atomic-resolution molecular movies provide us information on the 3-D structures of the molecules and also their time evolution. The success of the SMART-TEM imaging crucially depends on the development of "chemical fishhooks" with which fish (organic molecules) in solution can be captured on a single-walled carbon nanotube (CNT, serving as a "fishing rod"). The captured molecules are connected to a slowly vibrating CNT, and their motions are displayed on a monitor in real time. A "fishing line" connecting the fish and the rod may be a σ-bond, a van der Waals force, or other weak connections. Here, the molecule/CNT system behaves as a coupled oscillator, where the low-frequency anisotropic vibration of the CNT is transmitted to the molecules via the weak chemical connections that act as an energy filter. Interpretation of the observed motions of the molecules at atomic resolution needs us to consider the quantum mechanical nature of electrons as well as bond rotation, letting us deviate from the conventional statistical world of chemistry. What new horizons can we explore? We have so far carried out conformational studies of individual molecules, assigning anti or gauche conformations to each C-C bond in conformers that we saw. We can also determine the structures of van der Waals assemblies of organic molecules

  20. La discrimination positive, nouvelle pomme de discorde entre les partis politiques, le secteur privé et le pouvoir judiciaire en Inde Positive Discrimination: the New Bone of Contention between the Political Parties, the Private Sector and the Judiciary in India

    Directory of Open Access Journals (Sweden)

    Christophe Jaffrelot

    2009-03-01

    Full Text Available After the socio-political crisis that had resulted from the Mandal affair in 1990, no central government in India had any inclination to relaunch affirmative action programmes for fifteen years. The government that was formed after the 2004 elections resuscitated this question by committing itself to apply positive discrimination programmes in favour of the lower castes and the tribes in the private sector and in the domain of higher education. This move stems from the political strategy of the Congress party which aspires to regain some popularity among the plebeians and from the pressure exerted by the leftist component of the ruling coalition (the communists as well as regional parties. It has generated a lot of hostility from the business community, the upper caste students and the judiciary, but most of the opposition parties have approved this decision lest to alienate large chunks of the voters. As a result, the government has given up the idea of applying its policy to the private sector but it has had a bill passed in parliament for reserving 27% of the seats in the higher education system to the lower castesAprès la crise qu’avait constitué l’Affaire Mandal en 1990, les questions de discrimination positive ont été mises entre parenthèses en Inde au niveau du gouvernement central pendant quinze ans. Le nouveau pouvoir issu des élections de 2004 a remis cette problématique à l’ordre du jour en s’engageant à étendre la politique des quotas en faveur des castes inférieures et des tribus au secteur privé et à l’enseignement supérieur. Cette démarche s’explique à la fois par la tactique électorale du Congrès qui cherche à reprendre pied, politiquement, parmi la plèbe et par l’aiguillon que constituent les partis de gauche (communistes ou régionaux au sein de la coalition parlementaire. Elle a suscité l’hostilité des milieux d’affaires, des étudiants de haute caste et des juges mais la plupart des

  1. Discurso y violencia política en Sendero Luminoso

    Directory of Open Access Journals (Sweden)

    2000-01-01

    Full Text Available DISCOURS ET VIOLENCE POLITIQUE DU SENTIER LUMINEUX. Jusqu’en 1977, le Sentier Lumineux faisait partie des nombreux groupes appartenant à la gauche péruvienne radicale qui insistait sur la nécessité de recourir à la lutte armée en vue de prendre le pouvoir. La présente étude souligne l’importance d’éléments comme le discours, l’émergence d’une figure “ cosmocratique ” et la “ communauté de discours ” construite autour du mouvement armé dans le processus de transformation du Sentier Lumineux - alors un simple groupe marginal de province - qui est devenu une “ machine de guerre ” grâce à l’accumulation d’un “ capital symbolique ”. Le Sentier Lumineux a eu une influence marquante dans la vie politique du Pérou au cours des décennies 1980-1990 y compris après la capture de son principal chef (1992 et la décomposition du mouvement qui s’en est suivie. Hasta 1977, Sendero Luminoso era uno de los numerosos grupos de la izquierda radical peruana que pregonaban la necesidad de la lucha armada para conquistar el poder. El presente trabajo analiza la importancia que tuvo la elaboración de un discurso, la aparición de una “figura cosmocrática” y la construcción de una “comunidad-de-discurso” alrededor suyo, para explicar la transformación de SL, hasta entonces un grupúsculo marginal provinciano que, a partir de la acumulación de “capital simbólico”, se convirtió en una “máquina de guerra”. SL incidió de manera decisiva en la vida política peruana de las décadas de 1980 y 1990, incluso después de la captura de su líder máximo (1992 y su subsiguiente colapso. SHINING PATH’S DISCOURSE AND POLITICAL VIOLENCE. Until 1977, Shining Path (Sendero Luminoso was one of the numerous Peruvian extreme left-wing groups proclaiming for the armed struggle in order to seize power. This paper analyzes the importance of elaborating a discourse, the emergence of a “cosmocratic figure” and the elaboration of a

  2. Design and Function of a Brain Scanner for Clinical Use; Etude d'un Appareil de Scintigraphy du Cerveau - Son Role Clinique; Ustrojstvo i funktsiya pribora dlya skennirovaniya mozga i ego klinicheskoe ispol'zovanie; Diseffo y Funcion de un Aparato de Exploracion del Cerebro para Uso Clinico

    Energy Technology Data Exchange (ETDEWEB)

    Paul, W.; Morley, T. P. [Department of Pathological Chemistry and Department of Surgery, University Of Toronto (Canada)

    1964-10-15

    satisfaisante des zones de radioactivite accrue. Une delimitation precise n'etait pas necessaire. Le nombre de desintegrations detectees par unite de temps variant en fonction inverse du carre de la distance, on utilise deux detecteurs ayant chacun une courte focale, de preference a un detecteur qui doit etre regle sur le plan median du cerveau. Le detecteur a cristal de 5 cm de diametre et le photomultiplicateur sont montes l'un en face de l'autre sur un cadre rigide, chacun d'entre eux etant muni d*un collimateur a focalisation a sept canaux (hexagonal) ayant un diametre de resolution de 1.5 cm et un foyer a 8 cm de sa face anterieure. L'exploration est faite lineairement dans le plan sagittal. Le scintigramme se presente sous la forme d'un asymetrogammagramme et de representations photographiques separees, gauche et droite, a deux dimensions. Les impulsions de chaque detecteur passent dans un circuit amplificateur-discriminateur, puis dans un circuit differenciateur qui imprime un signe a gauche ou a droite pour indiquer une predominance de radioactivite a gauche ou a droite. Les impulsions sortant de chaque circuit amplificateur-discriminateur passent egalement dans des debitmetres qui, a leur tour, actionnent des lampes dans une chambre noire. Les deux lampes, dont l'intensite lumineuse est proportionnelle a l'activite mesuree par le detecteur correspondant, sont montees sur un meme support mu par des moteurs Selsyn synchronises avec des generateurs Selsyn fixes sur le cadre du detecteur, ce qui permet d'utiliser un dispositif enregistreur place a une grande distance. Des lentilles cylindriques focalisent la lumiere emise par les lampes sur un film, les enregistrements a droite et a gauche etant effectues simultanement sur un film a rayons X de 36 x 28 cm. Bien que l'operateur puisse regler le courant moyen des lampes a une valeur determinee a l'avance d'une gamme etendue de taux de comptage, il dispose d'une grande latitude grace a l'insertion dans le magasin de trois

  3. Morphology and optical properties of poly(9,9' dioctyfluorene) films

    International Nuclear Information System (INIS)

    Ariu, Marilu

    2002-01-01

    This thesis concerns a study of the optical properties of the polymer poly(9,9'dioctylfluorene) (PFO). Polyfluorene polymers represent the current state-of-the-art materials for use in optoelectronic devices. Recently there has been a growing interest in investigating how changes in polymer morphology affect their optical properties and in turn how such information can be used to optimise device performance. The first part of this thesis deals with the characterization of PFO films prepared in four morphological phases, namely: as spin coated glass (SC PFO), nematic quenched glass (NQ PFO), crystalline (X PFO) and PFO having an extended chain conformation (β-phase PFO). Infrared (FT-IR) and Raman spectroscopy have been used in order to correlate the polymer chain conformations in the four phases with the results reported from optical measurements. In order to do this, it has been necessary to analyse and assign the origin of the vibrational modes detected. This has been achieved via comparison with molecules chemically similar to PFO. Theoretical modelling has been used to confirm our assignment. The changes detected in the Raman and Infrared spectra indicate that the polymer chains adopt a longer conjugation length in the X and β-phase films. It appears that the side chains in the X PFO and β-phase conformation have a lower concentration of defects (alternation of gauche and trans conformation) than is observed in the SC film. Low temperature Raman and photoluminescence (PL) measurements are used to identify the vibrational modes that are more strongly coupled with the S 0- >S 1 electronic transition. The second part of this thesis leads with the study of the influence of temperature on the exciton migration process in the SC and β-phase films. At low temperature the migration process is slower and it is detectable via picosecond time resolved luminescence measurements. I have investigated the effect of temperature on the absorption, PL and PL efficiency (PLQY

  4. Efficacité d'un exutoire de dévalaison pour smolts de saumon atlantique (Salmo salar L. et comportement des poissons au niveau de l'aménagement hydroélectrique de Camon sur la Garonne

    Directory of Open Access Journals (Sweden)

    CROZE O.

    1999-04-01

    Full Text Available Trois expérimentations ont été conduites de 1996 à 1998 au niveau de la prise d'eau de l'usine hydroélectrique de Camon, sur la Garonne, de manière à tester l'efficacité d'un exutoire de surface destiné aux smolts de saumon atlantique. Ce dispositif de dévalaison est situé en rive gauche, au niveau du plan des grilles. Son efficacité a été évaluée par la méthode de marquage-recapture et le comportement des smolts dans le canal d'amenée a été suivi grâce à la technique de radio-pistage. L'efficacité initiale du dispositif est apparue faible en 1996 (moyenne de 34 % . Le suivi par radio-pistage a révélé que l'emplacement de l'exutoire n'était pas responsable de sa faible efficacité, les poissons stationnant préférentiellement à proximité. Cependant, la présence d'une ascendance masque son entrée. Suite à la mise en place d'une grille de tranquillisation et de platelages horizontaux au niveau de l'entrée de l'exutoire, cette efficacité a été portée à une valeur moyenne de 73 %. De bonnes conditions hydrauliques générales dans le canal d'amenée associées à une hydrodynamique locale favorable aux environs immédiats de l'entrée de l'exutoire s'avèrent indispensables à l'obtention d'une efficacité satisfaisante du dispositif de dévalaison. L'utilisation d'un éclairage nocturne intermittent a non seulement eu un effet sur le comportement des smolts dans le canal d'amenée en maintenant ces derniers dans les zones directement éclairées mais aussi sur les rythmes d'entrée des poissons dans l'exutoire, les passages apparaissant principalement en début d'extinction. La capture de 7 715 salmonidés sauvages a permis d'étudier les rythmes de dévalaison au niveau d'un obstacle. Les pics journaliers de passage semblent liés principalement à de forts débits et/ou à une augmentation de la température de l'eau. L'activité de dévalaison au niveau d'un obstacle apparaît en outre essentiellement

  5. Montage, Militancy, Metaphysics: Chris Marker and André Bazin

    Directory of Open Access Journals (Sweden)

    Sarah Cooper

    2010-01-01

    ;">, but that continues beyond Bazinřs death, in Markerřs two films made on the crest of the French New Wave: Le Joli Mai and La Jetée.

    Abstract (F:

     

    Cet article traite du lien entre les oeuvres d'André Bazin et de Chris Marker à partir de la fin des années 1940 jusqu'à la fin des années 1950 et au-delà. La distinction entre l'affiliation « rive droite » de Bazin avec Les Cahiers du cinéma d'une part, et, d'autre part, l'affiliation « rive gauche » de Marker est remise en question ici, dans la mesure où mon argumentaire cherche à brouiller les pistes de leur séparation idéologique conventionnelle. Avec un clin d'oeil allitératif, creusant le talent bien connu de Marker pour un montage subtil ainsi que son militantisme, j'examine l'éloge de Bazin pour

  6. Scintillation Scanning of the Spleen with Red Cells Labelled with Cr{sup 51}; Scintigraphie de la Rate au Moyen d'Hematies Marquees au Chrome-51; Stsintillyatsionnoe skennirovanie selezenki s pomoshch'yu ehritrotsitov mechennykh Khromom-51; Exploracion Centelleografica del Bazo Mediante Eritrocitos Marcados con Cromo-51

    Energy Technology Data Exchange (ETDEWEB)

    Spinelli-Ressi, F. [Istituto di Radiologia e Medicina Nucleare, Ospedale Maggiore, Milan (Italy)

    1964-10-15

    the scanning procedure has been used in objectively demonstrating modifications in spleen size after roentgen- ray therapy. (author) [French] L'auteur a obtenu des scintigrammes satisfaisants de la rate au moyen d'hematies marquees au chrome-51, alterees suivant deux methodes differentes. La methode utilisee en premier lieu consistait a sensibiliser les hematies in vitro en les revetant d'anticorps anti-D incomplet. Avec cette methode, la concentration dans la rate des hematies sensibilisees est proportionnelle au volume de serum anti-D utilise pour la sensibilisation. L'auteur a obtenu des scintigrammes satisfaisants en utilisant, par ml d'hematies, 0,50 ml de serum anti-D dilue a 1:128, dont le titre initial etait de 1:512. Bien qu*elle ait donne de bons resultats, la methode de sensibilisation, qui ne peut etre utilisee que chez des patients a Rh positif, a ete remplacee par une autre methode dans laquelle les hematies sont alterees thermiquement; cette seconde methode est techniquement plus facile et peut egalement etre appliquee chez des patients a Rh negatif. L'image de la rate est nettement delimitee dans tous les cas, sans interference due a la radioactivite hepatique. Le rapport rate:foie varie entre 5 et 10. A ce jour, l'auteur a etabli des scintigrammes de la rate pour une soixantaine de patients. Aucune reaction clinique, immediate ou differee, n*a ete observee a la suite de l'injection d'hematies sensibilisees ou alterees thermiquement. La dose de rayonnement delivree au patient etant inferieure a la dose administree dans de nombreux examens radiologiques et cliniques au moyen des radioisotopes, cette methode scintigraphique est largement utilisee a l'hopital de l'auteur pour le diagnostic differentiel des masses de la partie gauche de l'abdomen. Parmi les cas etudies, il convient de citer deux cas de splenomegalie associee a une tumeur du rein gauche, un cas de maladie de Banti chez un sujet presentant les symptomes d'un neoplasme du colon descendant et

  7. Comparison of brain mechanisms underlying the processing of Chinese characters and pseudo-characters: an event-related potential study.

    Science.gov (United States)

    Wang, Ting; Li, Hong; Zhang, Qinglin; Tu, Shen; Yu, Caiyun; Qiu, Jiang

    2010-04-01

    basis of orthographic, phonological and perceptual-semantic processing. La plupart des caractères chinois sont composés d'un radical sémantique à gauche et d'un radical phonétique à droite. Le radical sémantique peut fournir de l'information sémantique et le radical phonétique peut fournir de l'information concernant la prononciation du caractère entier. Les pseudo-caractères consistaient en différentes parties sous-lexicales des caractères chinois réels et, conséquemment, ils avaient aussi un radical sémantique et un radical phonétique. Mais ils ne pouvaient pas être lisibles et ils n'ont actuellement aucun sens. Afin d'étudier les patrons d'activation spatiotemporels corticaux sous-jacents aux traitements orthographique, phonologique et sémantique des caractères chinois, nous avons utilisé des Potentiels cérébraux reliés aux événements (PRE) pour explorer le traitement des caractères et des pseudo-caractères chinois auprès de 14 collégiens chinois visionnant les caractères passivement. Les résultats ont montré qu'à la fois les caractères et les pseudo-caractères chinois provoquaient un potentiel négatif évident atteignant un sommet autour de 120 ms (N120), ce qui apparaissait refléter la distinction et l'évaluation orthographiques initiales. Puis, les pseudo-caractères ont provoqué une déviation PRE plus positive (P220) que les caractères chinois entre 200 et 250 ms après l'apparition des stimuli. Ceci était similaire au PR (Potentiel de reconnaissance) et pouvait refléter les processus d'intégration des traitements phonologique et sémantique sur la base de l'information orthographique initiale. L'analyse dipôle de source de la différence de courbe (pseudo-caractères moins caractères) a indiqué qu'un générateur localisé dans la jonction temporo-occipitale gauche contribuait à cet effet, ce qui était possiblement relié à l'intégration de l'information phonologique et perceptuelle-sémantique. Entre 350 et

  8. Fast infrared spectroscopy in supercritical fluids

    International Nuclear Information System (INIS)

    Sun, X.

    2000-05-01

    the relative wavelength of the visible absorption maximum for Cr(CO) 5 Xe and Cr(CO) 5 (CO 2 ) all indicate a similar strength of interaction for Xe and CO 2 with the M(CO) 5 moiety. Chapter 4: Step-scan fourier transform time resolved infrared spectroscopy. In this chapter, conventional FTIR spectroscopy is introduced. Four methods of applying FTIR for time-resolved studies, i.e., rapid-scan FTIR, synchronous rapid-scan FTIR, asynchronous rapid-scan FTIR, and step-scan time-resolved FTIR are described. The using the step-scan FTIR spectrometer (Nicolet 860) in Nottingham for fast time resolved measurements is discussed. Time-resolved measurements on the photochemistry of [CpFe(CO) 2 ] 2 and Ciba Irgacure 184 in n-heptane solution show that this apparatus offers high spectral resolution, high sensitivity and fast time resolution. Chapter 5: Photochemistry of [CpMo(CO) 3 ] 2 and [Cp*Fe(CO) 2 ] 2 in supercritical CO 2 . This is the first study of the photochemistry of organometallic dimers in supercritical CO 2 . Radicals generated from visible (532nm) photolysis of [CpMo(CO) 3 ] 2 in scCO 2 , scXe, and n-heptane solution pressurised with CO 2 have been identified with ν(CO) bands. Three ν(CO) bands observed in scCO 2 and n-heptane solution pressurised with CO 2 , indicate coordination between Mo and CO 2 . A similar study with photolysis (532nm) of [Cp*Fe(CO) 2 ] 2 in scCO 2 finds no evidence of possible coordination between Fe and CO 2 . Radical recombination in scCO 2 is a second-order reaction. Study on pressure dependence of radical recombination rate shows no evidence of solvation enhancement on reaction rate in scCO 2 since the second-order rate constant is well below the diffusion controlled limit. lsomerisation of gauche-[CpMo(CO) 3 ] 2 and cis-[Cp*Fe(CO) 3 ] 2 is independent of the pressure of the solution. No cage effect is observed on the time scale of this measurement. Appendix: Three papers are attached outlining the work that I have completed during my

  9. Aspects de l’histoire de la sociologie en Grèce (1900-1980

    Directory of Open Access Journals (Sweden)

    Mélétis E. Mélétopoulos

    2008-12-01

    Full Text Available La sociologie grecque a été liée aux évolutions sociopolitiques et idéologiques du xxe siècle en Grèce. Dans le système politique, la sociologie a fonctionné comme point de repère légitimateur, comme paradigme et comme élément de modernisation. En même temps, les courants radicaux de gauche mais aussi de droite ont conçu la sociologie comme instrument de réforme sociale. Des revues importantes, tout au long du xxe siècle, ont prôné des idées radicales se basant sur la théorie sociologique. Après la 2ème Guerre Mondiale, l’État a organisé la recherche sociologique sur une base plus moderne et systématique, avec l’appui de la communauté sociologique occidentale. En même temps, la sociologie a été introduite dans les universités. Curieusement, les plus importants sociologues grecs du xxe siècle (parmi lesquels Nicos Poulantzas, Nicos Mouzélis, et avant eux Dimosthènes Danielidis, Avrotélis Eleftheropoulos et Constantinos Karavidas ont fait leur carrière à l’étranger ou sont resté à la marge des institutions étatiques et académiques grecques, ce qui peut s’explique par le fait que leurs idées conduisaient à la restructuration totale du système sociopolitique d’un pays en état de dépendance géopolitique et économique, comme était la Grèce au xxe siècle.Some Aspects of History of Sociology in Greece (1900-1980Sociology in contemporary Greece has had strong ties with the social, political and ideological evolutions. The discipline of sociology has functioned as a tool of modernization and social paradigm. In addition, the radical political movements of the Left as well of the Right, referred to the sociological theory as a mean of social reform. Major Greek sociological journals, during the 20th century, hosted radical ideas based on sociological theories. After the Second World War, consecutive Greek governments established institutions for scientific sociological research, assisted by the

  10. Book Reviews

    Directory of Open Access Journals (Sweden)

    F.J.M. Selier

    1985-01-01

    . Paris, CNRS, 1981, two tomes, 597 pp. - Silvia W. de Groot, Sally Price, Co-wives and calabashes, Ann Arbor, The University of Michigan Press, 1984, 224 p., ill. - N.O. Kielstra, Gene R. Garthwaite, Khans and Shahs. A documentary analysis of the Bakhtiary in Iran, Cambridge University Press, Cambridge, 1983. 213 pp. - G.L. Koster, Jeff Opland, Xhosa oral poetry. Aspects of a black South African tradition, Cambridge Studies in oral and literate culture 7, Cambridge University Press, Cambridge , London, New York, New Rochelle, Melbourne, Sydney, 1983, XII + 303 pp. - Adam Kuper, Hans Medick, Interest and emotion: Essays on the study of family and kinship, Cambridge University Press, 1984., David Warren Sabean (eds. - C.A. van Peursen, Peter Kloos, Antropologie als wetenschap. Coutinho, Muidenberg 1984 (204 p.. - Jerome Rousseau, Jeannine Koubi, Rambu solo’: “la fumée descend”. Le culte des morts chez les Toradja du Sud. Paris: Editions du CNRS, 1982. 530 pages, 3 maps, 73 pictures. - H.C.G. Schoenaker, Miklós Szalay, Ethnologie und Geschichte: zur Grundlegung einer ethnologischen geschichtsschreibung; mit beispielen aus der Geschichte der Khoi-San in Südafrika. Dietrich Reimer Verlag, Berlin 1983, 292 S. - F.J.M. Selier, Ghaus Ansari, Town-talk, the dynamics of urban anthropology, 170 pp., Leiden: E.J. Brill, 1983., Peter J.M. Nas (eds. - A.A. Trouwborst, Serge Tcherkézoff, Le Roi Nyamwezi, la droite et la gauche. Revision comparative des classifications dualistes. Cambridge: Cambridge University Press, Paris:Éditions de la Maison des sciences de l’homme, 1983, 154 pp. - Pieter van der Velde, H. Boekraad, Te Elfder Ure 32: Verwantschap en produktiewijze, Jaargang 26 nummer 3 (maart 1983., G. van den Brink, R. Raatgever (eds. - E.Ch.L. van der Vliet, Sally Humphreys, The family, women and death. Comparative studies. London, Boston etc.: Routledge & Kegan Paul, 1983 (International Library of Anthropology. xiv + 210 pp. - W.F. Wertheim, T. Svensson, Indonesia

  11. Las elecciones presidenciales de 1946 y el peronismo naciente vistos por el periódico La Vanguardia

    Directory of Open Access Journals (Sweden)

    Claudio Panella

    2004-09-01

    Full Text Available A travers cette étude, l’auteur analyse la position prise par le journal La Vanguardia, organe officiel du Parti Socialiste argentin, lors des élections présidentielles de 1946, élections qui marquèrent la naissance du mouvement politique péroniste. Ce fut la première élection depuis 1928 au cours de laquelle il n’y eut pas de fraude électorale. Elle permit la victoire de Juan Domingo Péron, qui devint ainsi le président constitutionnel de la République argentine. L’auteur analyse également le type de discours qu’employait le journal et les arguments dont il se servit pour rejoindre l’Union Démocratique et critiquer durement Péron, ainsi que les groupes politiques et sociaux qui l’appuyaient. Cette attitude politique éloigna définitivement les masses ouvrières des partis de gauche. Les dirigeants socialistes ne purent jamais l’empêcher, car ils avaient des concepts erronés à propos des besoins et des désirs de la classe ouvrière argentine de cette époque-là. C’est ainsi que, finalement, La Vanguardia, publication considérée en 1894 comme le « Journal Socialiste Scientifique. Défenseur de la classe ouvrière », finit en 1946 par s’identifier à des intérêts qui n’avaient rien à voir avec ceux des ouvriers.El objetivo del presente trabajo es el de brindar una aproximación a la visión que de las elecciones generales de 1946 y del naciente movimiento peronista tuvo el periódico La Vanguardia, órgano oficial del Partido Socialista. La contienda electoral fue la primera sin fraude desde 1928 y consagró presidente constitucional de la República Argentina a Juan Domingo Perón. Se analizará cómo el citado medio de prensa se posicionó frente a los comicios, que tipo de discurso utilizó y cuales fueron los argumentos que esgrimió para apoyar decididamente a la Unión Democrática y criticar con dureza a Perón y a las fuerzas políticas y sociales que lo apoyaban. Pero lo paradójico ha

  12. PREMIÈRE CARACTÉRISATION MORPHOLOGIQUE, BIOLOGIQUE ET GÉNÉTIQUE DES POPULATIONS DE GRANDE ALOSE (ALOSA ALOSA ET D’ALOSE FEINTE (ALOSA FALLAX SPP. DE LA CHARENTE (FRANCE.

    Directory of Open Access Journals (Sweden)

    VÉRON V.

    2001-07-01

    Full Text Available Les deux espèces d’aloses atlantiques (Alosa alosa et A. fallax colonisent la Charente mais leurs populations n’ont jamais été décrites à la différence de celles des grands fleuves français voisins. Les propriétés physiques du bassin sont présentées en terme de qualité de l’eau, d’habitats et d’obstacles à la migration. Les grandes aloses colonisent la Charente jusqu’en amont d’Angoulême (171 km lorsque les conditions hydrauliques des mois d’avril et mai effacent les 21 barrages situés en aval. Des frayères actives ont été localisées sur cette portion du fleuve. Les aloses feintes sont bloquées plus en aval par le barrage de Crouin (102 km, aval de Cognac et une seule frayère active a été repérée. L’abondance de ces deux stocks d’alose ne peut pas être estimée car les seules données disponibles, faute de dispositifs de contrôle des migrations, proviennent des captures faites par pêche professionnelle et à la ligne. La caractérisation morphologique et génétique des deux espèces a été faite à partir de comptages méristiques, de mesures morphométriques et de prélèvements (écaille, tissus et sang réalisés en 1997 et 1998. Le nombre total moyen de branchiospines du premier arc branchial gauche chez les grandes aloses est de 125 contre 42 chez les feintes. Quelle que soit l’espèce et à âge égal, les femelles ont une taille moyenne supérieure à celle des mâles. Les femelles de grande alose sont âgées en moyenne de 5 ans et les mâles de 4 ans, aucun des poissons échantillonnés ne présentant de marques de reproduction antérieure. Les femelles et les mâles d’alose feinte sont âgés en moyenne de 3 ans, 12,5 % des femelles se sont déjà reproduites une fois et 3,5 % deux fois. Chez les mâles, 40 % se sont déjà reproduits une fois. La plage temporelle de reproduction a été déterminée par suivi de terrain et enquête. Celle des grandes aloses se situe entre la premi

  13. De l’utopie socialiste au réalisme chrétien

    Directory of Open Access Journals (Sweden)

    Isabelle Richet

    2006-03-01

    Full Text Available Le New Deal est le premier mouvement réformiste d’ampleur dans l’histoire des Etats‑Unis qui n’ait pas été inspiré, ni soutenu, par les forces du protestantisme. Si une majorité des protestants et de leur clergé se sont opposés au New Deal à partir de positions conservatrices, le théologien Reinhold Niebuhr en a développé au départ une virulente critique de gauche avant de finalement rallier le président démocrate à la fin des années trente. Nourrie par le rejet de l’idéalisme du Social Gospel, incapable à ses yeux de comprendre les rapports sociaux en terme de classe et de pouvoir, la critique de Niebuhr emprunte les outils d’analyse marxistes pour développer une approche réaliste, tant du point de vue des fins que des moyens de la lutte politique. Le New Deal lui apparaît avant tout comme un programme visant à sauver le capitalisme, alors que la société fondée sur la justice qu’il envisage passe par la socialisation des moyens de production qui ne pourra émerger qu’à travers des conflits sociaux au cours desquels les moyens de lutte même violents sont justifiés. Mais sous l’influence des évènements en Europe au lendemain de la victoire d’Hitler, Reinhold Niebuhr se tourne au milieu des années trente vers une réflexion théologique inspirée de l’orthodoxie de Karl Barth et de son frère Richard Niebuhr, qui l’amène à réintroduire le péché comme la limite absolue de toute l’expérience humaine, interdisant d’envisager la création d’une société de paix et de justice. Ce nouvel absolutisme théologique nourrit un relativisme politique, le réalisme chrétien consistant désormais à choisir la moins mauvaise des options en présence. De ce point de vue, le président démocrate qui appelle à la préparation militaire s’impose désormais comme le choix le plus réaliste face à la montée du fascisme en Europe.The New Deal was the first major reformist experiment in the

  14. Représenter et penser l’affrontement : le magazine Vu face à la Guerre d’Espagne et à la menace d’une deuxième guerre mondiale

    Directory of Open Access Journals (Sweden)

    Sophie Kurkdjian

    2011-04-01

    Full Text Available Créé en 1928, Vu est un magazine qui confère à la photographie un nouveau rôle. Celle-ci constitue le propos même du magazine. Homme de gauche, son directeur, Lucien Vogel, est un pacifiste convaincu, dont le regard posé sur la période de l’entre-deux-guerres, plus précisément entre 1928 et 1936, est particulièrement intéressant à étudier. Cet article s’attachera à analyser la manière dont Vu couvre la Guerre d’Espagne et rapporte les tensions des années trente, héritées de la Première Guerre mondiale. Dans un premier temps, par l’intermédiaire de photographies et de mises en page destinées à marquer les esprits, Vu tente de prévenir un nouvel affrontement, la crainte d’une nouvelle guerre étant l’obsession de Lucien Vogel. Dans un second temps, lors de la Guerre d’Espagne, Vu prend, dès le début du conflit, fait et cause pour les Républicains espagnols. L’engagement de Lucien Vogel est tel qu’il est limogé par ses administrateurs qui lui reprochent d’avoir médiatisé l'événement avec un certain parti-pris. Ainsi, dans les deux cas, on se demandera jusqu’à quel point l’idéologie politique du directeur du magazine a un impact sur la représentation de cette période de crise et sur l’élaboration de la figure de l’ennemi. On montrera aussi que les nombreuses possibilités offertes par la photographie influencent la façon dont Lucien Vogel appréhende les événements de cette période.   Vu, created in 1928, is a magazine which endows photography with a new role, in that it became the very contents of the magazine. Its director, Lucien Vogel, is a convinced pacifist with left-wing commitments. His point of view on the period of time, in between the two world wars, is particularly interesting. Our article will study how, between 1928 and 1936, Vu reports the tensions inherited from World War I and covers the Spanish War.  In the first place, by means of photographs and eye

  15. Le parcours d’un juste: mémoires politiques, mémoires militantes

    Directory of Open Access Journals (Sweden)

    Alexandra Borsari

    2012-07-01

    citoyen ordinaire et de se démarquer du reste de la classe politique, il s'agira ainsi de voir ce qui, dans le récit, relève du mythe personnel et de son inscription dans une histoire plus large qui est celle d'une mythologisation de la gauche française. Le mythe sert ici de support au récit, pour donner du sens aux actes et les inscrire dans une histoire bien plus grandiose, démentant en cela la volonté d'humilité pourtant professée de la première à la dernière page. Cette posture n'est d'ailleurs pas sans poser problème dans la mesure où elle semble mettre à profit le discrédit croissant dont souffrent les élus et les décideurs politiques dans leur ensemble. Le combat tel qu'il est mené, en se posant sur le terrain de la morale, pourrait ainsi être interprété dans un tout autre sens que celui voulu par l'auteur.

  16. Le congréganiste hors la société ? Les dynamiques de laïcisation de la « République radicaliste » au prisme d’une approche d’anthropologie politique (France, 1902-1906

    Directory of Open Access Journals (Sweden)

    Julien Bouchet

    2012-09-01

    Full Text Available Au début du XXe siècle, la France de la « Belle Époque » connaît un temps de fondation républicaine qui rend de nouveau manifeste un conflit ancien sur la place du (des religieux dans le champ social. L’article porte sur l’exclusion des congréganistes du corps politique. Corollaire d’une laïcisation portée par les gauches parlementaires et soutenue par un anticléricalisme en recomposition, l’ostracisation des congréganistes passe par la stigmatisation de leurs corps, de leurs pratiques sociales et de leur appartenance à plusieurs entités essentialisées (« la Congrégation », « le parti noir ». Quoique pondérée par une domestication de la dissension, la violence de cet engagement appelle la fondation d’un nouveau contrat social car les autorités politiques restreignent par la coercition la capacité civile des congréganistes et leur interdisent d’enseigner tout en souhaitant accompagner leur « sortie de religion ». Le caractère a-libéral de cette idéologie acte les difficultés de l’État à penser ses relations avec les corps intermédiaires, et permet de discuter la thèse téléologique d’un procès de sécularisation qui se serait imposé en France sans heurts ni radicalisations.At the beginning of the twentieth century, France saw a period of republican progress, known as the « Belle Époque ». This period reintroduced the discourse regarding the extent of religious groups’ role in society. This article deals with the exclusion of religious people from positions within the political system. As a result, the Left secularized the parliament and ostracised these religious groups altogether through their social practices and limited membership in several essential government entities (« the Congregation » and « the black party ». The extremism of this commitment created the foundation for a new social contract in which the political authorities would restrict the civil capacity of

  17. Les recompositions politiques du mouvement féministe français au regard du hijab

    Directory of Open Access Journals (Sweden)

    Nicolas Dot-Pouillard

    2007-10-01

    Full Text Available L’exclusion d’un lycée public de deux jeunes filles voilées, en septembre 2004, et l’adoption de la loi relative à l’interdiction des signes religieux dans le primaire et secondaire de février 2005, ont posé la question de l’apparition de l’islam dans l’espace public. Mais la question du voile a débordé son objet premier, et a au final posé un certain nombre de questions relatives à la nature des liens entre l’espace public, l’État et la religion, à l’héritage et à l’impensé colonial, à ses conséquences sur les perceptions et les imaginaires collectifs. Ces problématiques ont littéralement déchiré le mouvement féministe français, et, au- delà, une large partie de la gauche française. C’est ainsi que le mouvement féministe français s’est vu littéralement coupé en trois positions : un nouveau féminisme républicain, fondé sur le paradigme assimilationiste et sur l’idée d’un espace public lisse et homogène, condition d’une véritable égalité ; un courant féministe historique, critiquant tout à la fois le voile comme instrument réactionnaire et la loi sur les signes religieux comme répressive et contre-productive ; un féminisme métisse enfin, dénonçant la vision coloniale de l’islam en France, et prêt à créer une transversalité entre féminisme occidental et féminisme musulman émergent.The exclusion from a French public college of two veiled girls, in September 2004, and the adoption of the law relating to the prohibition of the religious signs in the primary education and secondary of February 2005, raised the question of the appearance of Islam in public space. But the question of the veil overflowed its object first, and with final posed a certain number of questions relating to the nature of the bonds between public space, the State and the religion, with the heritage and impensé colonial, its consequences about perceptions and the imaginary collectives. These

  18. Loanwords in Cilubà

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    Ngo Semzara Kabuta

    2012-09-01

    ceux qui sont entièrement intégrés et, d'autre part, ceux qui, plus récents, retiennent un grand nombre de leurs traits phonologiques originels. Sur le plan phonologique, l'emprunt (1 introduit des phonèmes nouveaux tels que [R] et [g], (2 augmente la proportion des tons bas, et (3 introduit de nouvelles combinaisons de phonèmes (par exemple, dans la syllabe de type C1C2V, où les consonnes C1 et C2 doivent être respectivement une nasale et une semi-voyelle, les emprunts permettent la présence de consonnes quelconques. Sur le plan morphologique, on observe non seulement l'apparition de formes dont le pluriel n'est plus prévisible, mais aussi de formes qui peuvent former leur pluriel dans différentes classes. Ce phénomène a des implications importantes sur le plan lexicographique. En effet, il ne suffira plus désormais de mentionner dans un dictionnaire lubà la seule forme du singulier et de laisser au lecteur le soin d'en deviner la forme du pluriel. On est ainsi amené à développer pour les substantifs la notion de "genre". Celui-ci est défini comme une paire de classes dont les pôles gauche et droit, qui représentent généralement le singulier et le pluriel, sont choisis en fonction de leurs accords syntaxiques pour les différents affixes de classe (préfixes nominal, pronominal, verbal et objet; enclitiques, le possessif et les démonstratifs, et non plus seulement en fonction de la forme du préfixe nominal. Ainsi le genre d'un substantif s'avère être une donnée fondamentale dans la macrostructure d'un lemme substantival. Enfin, l'étude des procédés appliqués intuitivement par les locuteurs pour l'intégration de mots étrangers sera une source d'inspiration utile pour la création de néologismes.

     

  19. Pompage optique et violation de parité dans l'atome

    Science.gov (United States)

    Bouchiat, M.-A.

    èmes physiques abordés. Ceci illustre la richesse du champ de recherche ouvert sous l'impulsion de Kastler. La présentation adoptée ici fait le choix d'une description phénoménologique de l'expérience violation de parité dans le césium, indépendamment de toute référence à la théorie électrofaible. Ceci met en lumière les caractères remarquables du résultat qui semblent contredire tout le savoir du pompage optique. Lorsque la transition interdite 6S-7S du césium est excitée, l'orientation du spin électronique dans l'état 7S manifeste certaines anomalies. L'une est de caractère fondamental : il s'agit d'une asymétrie droite-gauche, manifestant une violation de la parité dont ne peut rendre compte la théorie EDQ. L'interprétation met en jeu plusieurs moments dipolaires de transition dont deux dipôles électriques, l'un induit par effet Stark et l'autre dirigé le long du moment angulaire de spin indiquant la présence d'une interaction électron-nucléon violant la parité. L'interférence des amplitudes de transition associée à ces deux dipôles produit une composante de l'orientation du spin dans l'état 7S se comportant de manière anormale : deux expériences images miroir l'une de l'autre conduisent pour cette composante à des résultats qui ne sont pas images miroir l'un de l'autre. Dans son principe, l'expérience consiste à étudier sur les propriétés de la lumière de fluorescence polarisée les effets produits par les réflexions miroirs réalisées par rapport à trois plans orthogonaux. Le contrôle de l'exactitude avec laquelle sont réalisées ces réflexions constitue la part cruciale de toute la procédure expérimentale. Dans notre expérience, aucune correction significative ne s'avère nécessaire. L'incertitude associée aux effets systématiques possibles est estimée à 8 %. En combinant les résultats de deux mesures indépendantes qui se recoupent de manière satisfaisante, l'incertitude statistique est 11 % (1 eqm). La

  20. Diagnosis and treatment of a local and afterwards generalized plutonium contamination; Diagnostic et traitement d'un cas d'intoxication par le plutonium local d'abord et generalise ensuite; Diagnoz i lechenie mestnogo i posledukshego generalizirovannogo porazheniya plutoniem; Diagnostico y tratamiento de una contaminacion local y luego general por plutonio

    Energy Technology Data Exchange (ETDEWEB)

    Lafuma, J. [Commissariat a l' Energie Atomique, Centre d' Etudes Nucleaires, Fontenay-aux-Roses (France)

    1963-02-15

    During an accident a technician's two hands were contaminated with hexaplutonium-239 nitrate. The contamination on the left hand alone, measured with an X-detector, was close on 60 {mu}c . The contamination was brought down to 15 {mu}c by a first decontamination carried out under a local anaesthetic; several contamination zones were localized by scanning. A surgical operation, done under an Esmach band with X and {alpha}-detectors, reduced the contamination from 15 to 5 {mu}c, the hands' functions being integrally preserved. A new zone of activity was localized by a second scan, and a second operation reduced internal contamination in the hand to 2 {mu}c. It has not been possible to localize this activity but it is kept under regular supervision. Parallel with the surgical decontamination, an internal decontamination with DTPA was undertaken. Blood, urine and faeces were sampled immediately after the accident and their activity was measured. Afterwards, urine samples were taken daily; blood and faecal samples were taken during each period of treatment. All the measurements indicate that DTPA is extremely effective in the case of internal contamination by Pu{sup 239}. It also appears that the percentage of blood plutonium eliminated by the kidney varies with time. The percentage increases, indicating that the plutonium is carried in the blood under different ionic or colloidal forms which are cleared in different degrees by the kidneys. It would accordingly appear that the activity in the urine does not faithfully reflect the internal contamination. (author) [French] Au cours d'un accident, les deux mains d'un technicien ont ete contaminees par du nitrate de plutonium-239 hexavalent. Pour la seule main gauche, la contamination, mesuree avec un detecteur de rayons X, etait voisine de 60 {mu}c. Une premiere decontamination, sous anesthesie locale, a permis de remener la contamination a 15 {mu}c . Grace a un , on a localise plusieurs zones de contamination

  1. Impact de la preparation des anodes crues et des conditions de cuisson sur la fissuration dans des anodes denses

    Science.gov (United States)

    Amrani, Salah

    classifier les differentes fissurations en plusieurs categories en se basant sur certains criteres tels que le type de fissures (horizontale, verticale et inclinee), leurs localisations longitudinales (bas, milieu et haut de l'anode) et transversales (gauche, centrale et droite). Les effets de la matiere premiere, les parametres de fabrication des anodes crues ainsi que les conditions de cuisson sur la fissuration ont ete etudies. La fissuration des anodes denses en carbones cause un serieux probleme pour l'industrie d'aluminium primaire. La realisation de ce projet a permis la revelation de differents mecanismes de fissuration, la classification de fissuration par plusieurs criteres (position, types localisation) et l'evaluation de l'impact de differents parametres sur la fissuration. Les etudes effectuees dans le domaine de cuisson ont donne la possibilite d'ameliorer l'operation et reduire la fissuration des anodes. Le travail consiste aussi a identifier des techniques capables d'evaluer la qualite d'anodes (l'ultrason, la tomographie et la distribution de la resistivite electrique). La fissuration des anodes en carbone est consideree comme un probleme complexe, car son apparition depend de plusieurs parametres repartis sur toute la chaine de production. Dans ce projet, plusieurs nouvelles etudes ont ete realisees, et elles permettent de donner de l'originalite aux travaux de recherches faits dans le domaine de la fissuration des anodes de carbone pour l'industrie de l'aluminium primaire. Les etudes realisees dans ce projet permettent d'ajouter d'un cote, une valeur scientifique pour mieux comprendre le probleme de fissuration des anodes et d'un autre cote, d'essayer de proposer des methodes qui peuvent reduire ce probleme a l'echelle industrielle.

  2. L’ombre du Condor

    Directory of Open Access Journals (Sweden)

    Franck Gaudichaud

    2003-09-01

    Full Text Available Si l’on observe aujourd’hui, avec un regard d’historien, le Cône Sud à la fin des années soixante soixante-dix et que par, la suite, on tourne une page de quelques années, pour fixer la même partie du monde, le constat est sans appel : le sous-continent latino-américain est passé, en général, d’une phase de forte mobilisation et politisation sociale, montée en puissance de partis et organisations révolutionnaires, surgissements de gouvernements populistes de gauche ou progressistes – appelant à une rupture avec l’impérialisme –, à un reflux généralisé du mouvement ouvrier, une ère de violence politique étatisée, la destruction massive de tous les espaces d’expression et de participation démocratiques, l’écrasement physique et idéologique sans relâche des militants et mouvements révolutionnaires, la mise en place de modèles économiques capitalistes dirigistes puis/ou néolibéraux. Que s’est-il passé ? Quel fil conducteur a été rompu et par quels moyens l’Amérique Latine a été conduite à ce reflux des luttes sociales ? Pour répondre à cette question, nous nous contenterons dans cet article de focaliser notre objectif sur un aspect spécifique et essentiel de ce retournement de tendance que vit alors l���Amérique Latine : celui de la mise en place d’un terrorisme d’Etat contre-révolutionnaire transnational, appuyé par l’impérialisme américain, nommé « l’Opération Condor ». Dans cet article, il s’agit de montrer le fonctionnement d’un terrorisme hégémonique dont l’impact sur les sociétés latino-américaines est considérable en termes de destruction du mouvement social, des activités culturelles et de l’ensemble de la vie sociale et politique qui restent marquées, encore aujourd’hui à des degrés divers, par la violence, la peur et l’atomisation structurelle.Si miramos hoy en día, desde una perspectiva histórica, el Cono Sur hacia finales de

  3. A pilot study of the efficacy of wipes containing chlorhexidine 0.3%, climbazole 0.5% and Tris-EDTA to reduce Malassezia pachydermatis populations on canine skin

    Science.gov (United States)

    Cavana, Paola; Peano, Andrea; Petit, Jean-Yanique; Tizzani, Paolo; Perrot, Sébastien; Bensignor, Emmanuel; Guillot, Jacques

    2015-01-01

    -EDTA contre Malassezia pachydermatis. Sujets Cinq colonies de shar-pei de recherche. Méthodes Les lingettes ont été appliquées une fois par jour au niveau du pli axillaire gauche, le pli inguinal droit et de la zone périanale(protocole A) et deux fois par joursur le pli axillaire droit, le inguinal droit et l'ombilic (protocole B) pendant 3 jours. L'activité in vivo a été évaluée par quantification des colonies de Malassezia par disques de contact sur les zones corporelles choisies avant et après application des lingettes. L'activité de la solution d'imprégnation des lingettes a été testée in vitro par tests de contact suivant les recommandations de l'European Standard UNI EN 1275. Résultats Les échantillons prélevés après application ont montré une diminution importante et rapide des CFU des levures Malassezia. Aucune différence significative dans la diminution des Malassezia n'a été mise en évidence entre les protocoles A et B. Des tests in vitro ont montré 100% d'activité contre les Malassezia après un temps de contact de 15 minutes avec la solution des lingettes. Conclusions et importance Clinique Les lingettes contenant la chlorhexidine, le climbazole et le Tris-EDTA réduisent substantiellement la population de M. pachydermatis sur la peau des chiens. Les résultats, bien qu'il s'agisse d'une étude non contrôlée réalisée sur un faible nombre de chiens, suggère que ces lingettes peuvent être utiles en traitement local de la dermatite à Malassezia des lèvres, des pattes, du périnée et des plis cutanés. Resumen Introducción las gasas que contienen clorhexidina y derivados de azol son recomendadas para uso veterinario. No se ha publicado ningún estudio acerca su actividad contra Malassezia paquidermatis. Hipótesis/Objetivos evaluar la actividad in vivo e in vitro de las gasas con clorhexidina, climbazol y soluciónb Tris-EDTA frente a Malassezia pachydermatis Animales cinco colonias de investigación de perros Sharpei. M