Search results for "insertion"

Near-infrared imaging and structured light ranging for automatic catheter insertion

2006

Vein localization and catheter insertion constitute the first and perhaps most important phase of many medical procedures. Currently, catheterization is performed manually by trained personnel. This process can prove problematic, however, depending upon various physiological factors of the patient. We present in this paper initial work for localizing surface veins via near-infrared (NIR) imaging and structured light ranging. The eventual goal of the system is to serve as the guidance for a fully automatic (i.e., robotic) catheterization device. Our proposed system is based upon near-infrared (NIR) imaging, which has previously been shown effective in enhancing the visibility of surface vein…

Inégalités territoriales dans l'accès à l'alternance : le cas des jeunes des QPV

2023

Mechanistic Study of Stepwise Methylisocyanide Coupling and C-H Activation Mediated by a Low-Valent Main Group Molecule

2013

An experimental and DFT investigation of the mechanism of the coupling of methylisocyanide and C-H activation mediated by the germylene (germanediyl) Ge(Ar(Me6))2 (Ar(Me6) = C6H3-2,6(C6H2-2,4,6-Me3)2) showed that it proceeded by initial MeNC adduct formation followed by an isomerization involving the migratory insertion of the MeNC carbon into the Ge-C ligand bond. Addition of excess MeNC led to sequential insertions of two further MeNC molecules into the Ge-C bond. The insertion of the third MeNC leads to methylisocyanide methyl group C-H activation to afford an azagermacyclopentadienyl species. The X-ray crystal structures of the 1:1 (Ar(Me6))2GeCNMe adduct, the first and final insertion …

Reactivity and Selectivity of Ortho-Metalated Rhodium(II) Complexes in C−H Insertion Reactions of α-Diazo Compounds

1998

Regioselective intramolecular C−H insertion reactions of α-diazo β-keto esters and α-diazo ketones are mediated by Rh2[OOCR]4-x[PC]x (x = 1, 2; PC = ortho-metalated phosphine; R = CH3, C3F7). In particular, the intramolecular transformation of 1-diazo-5-methyl-3-propyl-2-hexanone catalyzed by Rh2[OOCCH3]2[PC]2 (PC = (C6H4)P(C6H5)2, head-to-tail (H−T) configuration) afforded only the tertiary C−H insertion product. By comparison, no C−H insertion reaction was promoted by doubly metalated complexes with a head-to-head (H−H) configuration. Rh2[OOCR]3[PC] compounds were found to be less suited for these type of reactions.

Le syndrome du diplôme et le chômage des jeunes diplômés, le cas de la Haute-Volta

1983

Référence interne : 83046

Diastereoselective Insertion of Isocyanide into the Alkyl−Metal Bond of Methylbenz[ e ]indenyl ansa ‐Zirconocene Complexes

2004

Alkylation of ansa-zirconocene [Zr{(η5-C5H5)SiMe2(MBI)}Cl2] (MBI = η5-2-Me−C13H7) with MgRCl gave the dimethyl complex [Zr{(η5-C5H5)SiMe2(MBI)}Me2], but unresolvable mixtures containing mono-alkylated compounds were obtained when bulkier alkyls were used. However pure dialkyl complexes [Zr{(η5-C5H5)SiMe2(MBI)}R2] (R = CH2Ph, CH2SiMe3) were easily obtained using K(CH2Ph) and Li(CH2SiMe3) as alkylating agents. Diastereoselective insertion into the MBI-unprotected Zr−R bond was observed when all of these dialkyl complexes were treated with 2,6-xylyl isocyanide to give the iminoacyl compounds [Zr{(η5-C5H5)SiMe2(MBI)}R{CR[η2-N-(2,6-xylyl)]}] (R = Me, CH2Ph, CH2SiMe3). All of the new complexes we…

Roles of a conserved proline in the internal fusion peptide of Ebola glycoprotein

2004

AbstractThe structural determinants underlying the functionality of viral internal fusion peptides (IFPs) are not well understood. We have compared EBOwt (GAAIGLAWIPYFGPAAE), representing the IFP of the Ebola fusion protein GP, and EBOmut (GAAIGLAWIPYFGRAAE) derived from a non-functional mutant with conserved Pro537 substituted by Arg. P537R substitution did not abrogate peptide-membrane association, but interfered with the ability to induce bilayer destabilization. Structural determinations suggest that Pro537 is required to preserve a membrane-perturbing local conformation in apolar environments.

Les jeunes en situation de NEET : le rôle des compétences de base

2021

International audience; Enjeu prioritaire des politiques publiques nationales et européennes, les jeunes qui ne sont ni en emploi, ni en études, ni en formation connaissent un risque d’exclusion plus ou moins marqué selon les pays. Si le niveau d'éducation joue un rôle central dans ces situations, l’approche par les compétences de base permet d’affiner la focale. Les données internationales montrent en effet qu’un même niveau de diplôme ne certifie pas partout le même niveau de compétences. Comment s’expliquent ces écarts ? Dans quelle mesure ces compétences protègent-elles des situations de NEET indépendamment du diplôme ?

La population étudiante à l'épreuve des comparaisons internationales

2019

International audience; Deux grands types d'enquêtes originales permettent de cerner les mondes étudiants dans l'espace européen de l'enseignement supérieur. Ce chapitre dévoile les principaux résultats en matière de conditions de vie des étudiant-e-s et d’insertion professionnelle en l’illustrant par les spécificités des étudiants au cœur de neuf pays qui ont participé à ces projets depuis 1999. Le croisement des informations, qui reposent sur les expériences et les perceptions des jeunes, permet de dégager les tendances communes au niveau de l'Europe et de saisir les particularités de chaque pays. Malgré certaines similitudes avec l'ensemble des diplômé-e-s européens, les conditions de vi…

Factors Behind Junk DNA in Bacteria

2012

Although bacterial genomes have been traditionally viewed as being very compact, with relatively low amounts of repetitive and non-coding DNA, this view has dramatically changed in recent years. The increase of available complete bacterial genomes has revealed that many species present abundant repetitive DNA (i.e., insertion sequences, prophages or paralogous genes) and that many of these sequences are not functional but can have evolutionary consequences as concerns the adaptation to specialized host-related ecological niches. Comparative genomics analyses with close relatives that live in non-specialized environments reveal the nature and fate of this bacterial junk DNA. In addition, the…