0000000000183840
AUTHOR
François Béland
Fragilité, vulnérabilité et ressorts de santé des personnes âgées
National audience; A partir d’observations socio ethnographiques à domicile, cet article explore les conditions d’application des notions de fragilité, vulnérabilité et atouts / ressorts de santé au repérage, au suivi et à la prévention de la perte d’autonomie des personnes âgées. Relevant d’univers différents, ces trois notions offrent des cadres d’analyse et d’intervention complémentaires. La notion de fragilité, dans son acception gériatrique, appartient à l’univers de la maladie ; elle se présente comme une diminution plus ou moins étendue des réserves physiologiques qu’un individu mobilise face à un stress. Les atouts / ressorts de santé se situent d’emblée dans le domaine de la santé,…
Heterogeneous vs Homogeneous Palladium Catalysts for Cross-Coupling Reactions
A large number of immobilized-Pd-catalysts for cross-coupling reactions have been introduced in the last decade. Are the observed catalyzed reactions truly heterogeneous or are they homogeneous due to leached palladium? This account critically addresses the leaching issue by selectively referring to some of the newly developed catalytic systems in an attempt to evaluate said systems based on uniform criteria. The report is concluded by identifying the relevant chemical and structural challenges in the field.
A new class of heterogeneous Pd catalysts for synthetic organic chemistry
A new series of leach-proof nanostructured Pd(0) catalysts able to catalyze a number of fundamental organic transformations including C–C bond formation has been developed. Reactions in general proceed with high yield and often at completion, while the catalysts can be reused in further reaction runs. This establishes a new class of relevant solid catalysts for synthetic organic chemistry trademarked SiliaCat Pd0 Hydrogel.
Green and Direct Synthesis of Benzaldehyde and Benzyl Benzoate in One Pot
High yields of valued benzaldehyde and benzyl benzoate are obtained in one pot starting from benzyl alcohol using oxygen as only oxidant under mild conditions (2 bar O2, 100 °C) along with an ultralow amount (0.02 mol %) of Au nanoparticles heterogenized over a spherical ORMOSIL mesoporous support. The process is remarkably selective and the catalyst is stable.
Heterogeneously catalyzed Suzuki-Miyaura conversion of broad scope
The reaction tolerates a broad range of functional groups in the coupling partners and is usually performed in solution under homogeneous conditions at T ¢ 60 uC using 2–3 mol% catalytic amounts. The catalyst is often a Pd(0) complex with triarylphosphane ligands. 2 The catalytic cycle (Scheme 2) begins with the oxidative addition of an aryl halide to a Pd(0) species formed in situ to form an arylpalladium(II) halide intermediate. 3 Chloroarenes, especially nonactivated aryl chlorides, are notoriously less reactive due to the stability of the C–Cl bond (the relative reactivity of Ar–X is correlated to the respective bond dissociation energy: Ph–Cl: 96 kcal mol 21 ,P h–Br: 81 kcal mol 21 ,P …
Enhanced Heterogeneously Catalyzed Suzuki-Miyaura Reaction over SiliaCat Pd(0)
Abstract The SiliaCat Pd(0) solid catalyst can be efficiently employed in the Suzuki–Miyaura cross-coupling of an ample variety of haloarenes, including economically viable chloroarenes. The catalyst can be extensively recycled without loss of activity and with low leaching of valued palladium, opening the route to widespread utilization of the method to afford high yields of biaryls devoid of contaminating by-products.
Heterogeneous Sonogashira Coupling over Nanostructured SiliaCat Pd(0)
Sol–gel entrapped catalyst SiliaCat Pd(0) heterogeneously mediates the Sonogoashira coupling of different aryl halides and phenylacetylene either under thermal conditions or, much more efficiently, under microwave irradiation, affording good conversions of coupled products. Leaching of valued Pd is limited, and the catalyst can be reused.
Characterization of Nanostructured SilicaCat Pd0
Structural investigation on nanostructured SiliaCat Pd0 palladium catalyst sheds light into the origins of the remarkable activity of these new catalytic materials.
Searching for an Operational Definition of Frailty: A Delphi Method Based Consensus Statement. The Frailty Operative Definition-Consensus Conference Project.
International audience; Abstract BACKGROUND: There is no consensus regarding the definition of frailty for clinical uses. METHODS: A modified Delphi process was used to attempt to achieve consensus definition. Experts were selected from different fields and organized into five Focus Groups. A questionnaire was developed and sent to experts in the area of frailty. Responses and comments were analyzed using a pre-established strategy. Statements with an agreement more than or equal to 80% were accepted. RESULTS: Overall, 44% of the statements regarding the concept of frailty and 18% of the statements regarding diagnostic criteria were accepted. There was consensus on the value of screening fo…