Enantioselective hydrogenation of activated ketones in the presence of Pt–cinchona catalysts. Is the proton transfer concept valid?

Experimental evidences related to the proton transfer in the catalytic system Pt-Cinchona alkaloids for enantioselective hydrogenation of activated ketones were collected and analyzed. Both new and earlier results indicate that in aprotic media direct transfer of proton from platinum to the substrate with the involvement of quinuclidine nitrogen as a general rule can be questioned

Fémion-fémnanoklaszter aktívhely együttesek. Képződésük, szerkezetük és katalitikus sajátságuk felderítése = Metallic ion-metal nanocluster active site ensembles: Investigation of their formation, structure and catalytic properties

Az elvégzett munka az alábbi részfeladatokra terjedt ki: 1. Különböző típusú fémion-fémnanoklaszter aktívhely együttest tartalmazó Au katalizátorok Különböző hordozós aranykatalizátorokat állítottunk elő, melyek aktivitását CO oxidációjában vizsgáltuk. Kimutattuk, hogy a MgO hordozós arany katalizátorokon a Audelta+ - Auo aktívhely együttesek a 273 K alatti, míg a Mn+ - Auo aktívhely együttesek (M= Fe, Mn, Pb) a 300 K feletti aktivitásért felelősök. Bizonyítottuk, hogy MgO, Al2O3 és SiO2 hordozós Au katalizátorok nagy aktivitását jelentős mértékben megváltoztatja az Au nano-környezete, azaz a képződött Mn+ - Auo aktívhely együttesek. 2. Fen+ - Fe0 aktívhely együttest tartalmazó katalizátorok vizsgálata. Fe-MCM-41 katalizátort állítottunk elő és vizsgáltuk katalitikus aktivitását CO oxidációjában. Kimutattuk, hogy a katalizátorok aktivitása csak magas hőmérsékleten végbemenő reduktív kezelés hatására alakul ki. FTIR módszerrel bizonyítékot kaptunk a ""Fen+ -Feo"" aktívhely együttes képződéséről, ha a katalizátort 500 oC hőmérséklet felett H2 atmoszférában redukáltuk. 3. A ""PdO-Pdo"" ""FIFNK aktívhely együttesek"" szerepe a CH4 oxidációjában. In situ XPS vizsgálatokkal bizonyítottuk, hogy a CH4 oxidációjában igen aktív Pt-Pd-Au/CeO2 katalizátorokban mind a Pt, mind a kismennyiségű Au bevitele jelentős mértékben csökkenti a CeO2 hordozón stabilizálódott ionos Pd mennyiségét növelve ezáltal az in situ képződött ""PdO-Pdo"" aktívhely együttesek felületi koncentrációját. | Tasks explored in this project: 1. Preparation and testing of supported gold catalyst containing different types of metal ion-metal nanocluster ensemble sites. Different supported Au catalysts were prepared and tested in CO oxidation. It has been shown that Audelta+ - Auo type ensemble sites are responsible for the high activity below 273 K, while the Mn+ - Auo ensemble sites (M= Fe, Mn, Pb) are involved in the activity increase above 300 K. It has been shown that the activity of these catalysts is controlled by (i) the particle size of Au, and (ii) the nano-environment of Au, i.e., the formation and stabilization of Mn+ - Auo type ensemble sites. 2. Investigation of catalysts containing Fen+ - Fe0 ensemble sites. Iron containing Fe-MCM-41 catalyst were prepared and tested in CO oxidation. The activity of these catalysts appeared only after reduction in H2 above 500 oC. Upon using FTIR technique evidences were obtained for the formation of "Fen+ -Feo" ensemble sites. 3. The role of "PdO-Pdo" type ensemble sites in the total oxidation of methane. In situ XPS studies were performed to elucidate the role of Pt and Au in Pt-Pd-Au/CeO2 catalysts. These catalysts showed high activity in total CH4 oxidation. The results showed that the addition of Pt and small amount of Au decreases the ionic form of Pd stabilized over CeO2 support. Consequently, the addition of both Pt and Au increased the surface concentration of "PdO-Pdo" type ensemble sites formed in situ during the reaction

International expert consensus on a scientific approach to training novice cardiac resynchronization therapy implanters using performance quality metrics

Aims: Pacing and Cardiac Resynchronization Therapy (CRT) procedural training for novice operators usually takes place in-vivo and methods vary across countries/institutions. No common system exists to objectively assess trainee ability to perform required tasks at predetermined performance levels prior to in-vivo practice. We sought to characterize and validate with experts a reference approach to pacing/CRT implants based on objective and explicit performance quality metrics, for the development of a reproducible, simulation-based, training curriculum aiming to operator proficiency. Methods: Three experienced CRT implanters, a behavioural scientist and two engineers performed a detailed task deconstruction of the pacing/CRT procedure and identified the performance metrics (phases, steps, errors, critical errors) that constitute an optimal CRT implant for training purposes. The metrics were stress tested to determine reliability and score-ability and then subjected to detailed systematic review by an international panel of 15 expert implanters in a modified Delphi process. Results: Thirteen procedure phases were identified, consisting of 196 steps, 122 errors, 50 critical errors. The expert panel deliberation added 16 metrics, deleted 12, and modified 43. Unanimous panel consensus on the resulting CRT procedure metrics was obtained, which verified face and content validity. Conclusion: A reference pacing/CRT procedure and metrics created by a core group of experts accurately characterize the essential components of performance and were endorsed by an international panel of experienced peers. The metrics will underpin quality-assured novice implanter training

International expert consensus on a scientific approach to training novice cardiac resynchronization therapy implanters using performance quality metrics

Aims: Pacing and Cardiac Resynchronization Therapy (CRT) procedural training for novice operators usually takes place in-vivo and methods vary across countries/institutions. No common system exists to objectively assess trainee ability to perform required tasks at predetermined performance levels prior to in-vivo practice. We sought to characterize and validate with experts a reference approach to pacing/CRT implants based on objective and explicit performance quality metrics, for the development of a reproducible, simulation-based, training curriculum aiming to operator proficiency. Methods: Three experienced CRT implanters, a behavioural scientist and two engineers performed a detailed task deconstruction of the pacing/CRT procedure and identified the performance metrics (phases, steps, errors, critical errors) that constitute an optimal CRT implant for training purposes. The metrics were stress tested to determine reliability and score-ability and then subjected to detailed systematic review by an international panel of 15 expert implanters in a modified Delphi process. Results: Thirteen procedure phases were identified, consisting of 196 steps, 122 errors, 50 critical errors. The expert panel deliberation added 16 metrics, deleted 12, and modified 43. Unanimous panel consensus on the resulting CRT procedure metrics was obtained, which verified face and content validity. Conclusion: A reference pacing/CRT procedure and metrics created by a core group of experts accurately characterize the essential components of performance and were endorsed by an international panel of experienced peers. The metrics will underpin quality-assured novice implanter training

CRT Survey II: a European Society of Cardiology survey of cardiac resynchronisation therapy in 11 088 patients—who is doing what to whom and how?

Background: Cardiac resynchronisation therapy (CRT) reduces morbidity and mortality in appropriately selected patients with heart failure and is strongly recommended for such patients by guidelines. A European Society of Cardiology (ESC) CRT survey conducted in 2008–2009 showed considerable variation in guideline adherence and large individual, national and regional differences in patient selection, implantation practice and follow-up. Accordingly, two ESC associations, the European Heart Rhythm Association and the Heart Failure Association, designed a second prospective survey to describe contemporary clinical practice regarding CRT. Methods and results: A survey of the clinical practice of CRT-P and CRT-D implantation was conducted from October 2015 to December 2016 in 42 ESC member countries. Implanting centres provided information about their hospital and CRT service and were asked to complete a web-based case report form collecting information on patient characteristics, investigations, implantation procedures and complications during the index hospitalisation. The 11 088 patients enrolled represented 11% of the total number of expected implantations in participating countries during the survey period; 32% of patients were aged ≥75 years, 28% of procedures were upgrades from a permanent pacemaker or implantable cardioverter-defibrillator and 30% were CRT-P rather than CRT-D. Most patients (88%) had a QRS duration ≥130 ms, 73% had left bundle branch block and 26% were in atrial fibrillation at the time of implantation. Large geographical variations in clinical practice were observed. Conclusion: CRT Survey II provides a valuable source of information on contemporary clinical practice with respect to CRT implantation in a large sample of ESC member states. The survey permits assessment of guideline adherence and demonstrates variations in patient selection, management, implantation procedure and follow-up strategy

Gold nanoparticles supported on magnesium oxide for CO oxidation

Au was loaded (1 wt%) on a commercial MgO support by three different methods: double impregnation, liquid-phase reductive deposition and ultrasonication. Samples were characterised by adsorption of N2 at -96°C, temperature-programmed reduction, high-resolution transmission electron microscopy, energy-dispersive X-ray spectroscopy and X-ray diffraction. Upon loading with Au, MgO changed into Mg(OH)2 (the hydroxide was most likely formed by reaction with water, in which the gold precursor was dissolved). The size range for gold nanoparticles was 2-12 nm for the DIM method and 3-15 nm for LPRD and US. The average size of gold particles was 5.4 nm for DIM and larger than 6.5 for the other methods. CO oxidation was used as a test reaction to compare the catalytic activity. The best results were obtained with the DIM method, followed by LPRD and US. This can be explained in terms of the nanoparticle size, well known to determine the catalytic activity of gold catalysts

Improved electrocatalytic stability in ethanol oxidation by microwave-assisted selective deposition of SnO2 and Pt onto carbon

Pt/SnO2/C nanostructures with SnO2/Pt molar ratios ranging from 2.5 to 0.6 were synthesized by simple and fast microwave-assisted routes. The materials are composed of 3-5 nm SnO2 and Pt nanoparticles dispersed on the carbon support, with the morphology of the coating depending on the SnO2/Pt ratio: a homogenous layer of nanoparticles coating the carbon surface is obtained for SnO2/Pt of 2.5, whereas small Pt-SnO2 clusters are formed for lower ratios. The electrocatalytic activity of the composites on the ethanol oxidation reaction (EOR) was studied by cyclic voltammetry and chronoamperometry. All the binary catalysts exhibited lower onset potentials for the EOR and slower decay of the current density with time than a commercial Pt/C catalyst. However, improved peak current densities were only observed for the composites with ratios 1.6, 1.0 and 0.6, indicating that the formation of metal and metal oxide nanoparticles clusters is favorable for the EOR. This morphology facilitates the hydroxyl groups transfer from the metal oxide to the platinum at low potentials and also the electron transfer between carbon and platinum. The best overall performance was found for the catalyst with SnO2/Pt = 1, on which the number of three-phase boundaries is maximized. Moreover, the catalyst with SnO2/Pt = 1 continued to exhibit significantly better catalytic performance on the EOR than the commercial catalyst after potential cycling