4,513 research outputs found
Reverse shoulder Arthroplasty. Current techniques and complications
No full textThis handbook fully investigates reverse shoulder arthroplasty (RSA), presenting all the recent advances in the field to enable shoulder surgeons to treat patients with complex conditions, such as rotator cuff tears and instability, failed surgery and combined arthritis, or proximal humerus neoplasia.
Reverse shoulder arthroplasty is becoming increasingly common because conventional total shoulder replacement may cause pain, loss of strength, simple or complex disabilities as well as limited motion, reducing general quality of life. The goal of a reverse prosthesis is to restore a painless, biomechanically valid joint. Drawing on the results of recent studies, the book covers all relevant aspects of RSA, including basic science, pathogenesis, clinical and instrumental evaluation, surgical techniques and complication management, helping readers to better understand when and how reverse shoulder arthroplasty should be implanted and what to do in cases of poor results. Written by leading shoulder specialists, the book provides surgeons and rehabilitation specialists, as well as residents and shoulder fellows, with a valuable, state-of-the-art guide for clinical practice
Selective and Efficient Reduction of Nitrobenzene to Aniline catalyzed by AuNPs Embedded in a Nanoporous Crystalline Polymeric Support
No full textCongresso Divisione Chimica Industriale
Salerno, Settembre 2015
Selective and Efficient Reduction of Nitrobenzene to Aniline catalyzed
by AuNPs Embedded in a Nanoporous Crystalline Polymeric Support
Annarita Noschese1*, Antonio Buonerba1, Carmine Capacchione1, Stefano Milione1, Alfonso Grassi1
1 - Dipartimento di Chimica e Biologia, Università degli Studi di Salerno, Via Giovanni Paolo II - 84084 Fisciano (SA), Italy, and CIRCC-Bari, Italy
Abstract
Supported Gold Nanoparticles (AuNPs) efficiently catalyze both oxidation and reduction reactions. E.g. aerobic oxidation of alcohols and cross coupling reactions of alcohols leading to esters, amide, imine have been widely and successfully explored [1]. On the other side the reduction of nitroarenes to anilines using NaBH4, H2, silanes, formic acid, CO/H2O is a benchmark reaction for testing their catalytic performances in reduction reactions [2].
During reaserch efforts many supports have been exploited (carbon based supports, polymers, inorganic oxides) but their role is still under discussion. A semicrystalline porous polymeric support, consisting of syndiotactic polystyrene-co-cis-1,4-polybutadiene [3] has been successfully tested in our group and the AuNPS embedded in this polymer matrix (AuNPs-sPSB) were investigated in the reduction of nitrobenzene to aniline. The polymorphic behaviour of the host polymer matrix has been studied to optimize the catalyst performances. The nanoporous crystalline forms of the sPSB matrix, namely and , allowed a total conversion of nitrobenzene in 40 min at room temperature, with 100% selectivity in aniline. On the contrary the not permeable crystalline form gave a less reactive and selective catalyst; actually azobenzene and azoxybenzene were detected as intermediates compounds providing information on the cascade of the reduction reactions and the global reaction mechanism. Among the catalysts to date reported in the literature, the AuNPs-sPSB catalyst showed the highest activity (TOF=6000 h-1). The catalyst is very stable under the reaction conditions and reusable for at least three times without loss of catalytic activity.
Keywords: Gold Nanoparticles, Polymeric Matrix, Reduction.
* Corresponding author: [email protected]
References
[1] A. Corma, H. Garcia, Chem. Soc. Rev. 37 (2008) 2096
[2] S. Fountoulaki, V. Daikopoulou, P. L. Gkizis, I. Tamiolakis, G.S. Armatas, I. N. Lykakis, ACS Catal. 4 (2014) 3504; X. Liu, S. Ye, H.-Q. Li, Y.-M. Liu, Y. Cao, K.-N. Fan, Catal. Sci. Technol. 3 (2013) 3200; L. He, L.-C. Wang, H. Sun, J. Ni, Y. Cao, H.-Y. He, K.-N. Fan, Angew. Chem. Int. Ed. 48 (2009) 9538.
[3] A. Buonerba, C. Cuomo, S. Ortega Sánchez, P. Canton, A. Grassi, Chem. Eur. J. 18 (2012) 709; A. Buonerba, A. Noschese, A. Grassi, Chem. Eur. J. 20 (2014) 5478
Thermoremendable Styrenic Polymers by Controlled Radical Copolymerization of Styrene with bioderived 2-vinylfuran
No full textThermoremendable Styrenic Polymers by Controlled Radical Copolymerization of Styrene with bioderived 2-vinylfuran
A. Grassi,* A. Buonerba, C. Capacchione, S. Milione
Department of Chemistry and Biology “Adolfo Zambelli”, University of Salerno – Italy
CIRCC - Interuniversity Consortium on Chemical Reactivity and Catalysis
*Corresponding author: [email protected]
Keywords: Biosourced olefins, functional olefin copolymer, furan-maleimide Diels Alder reaction.
Abstract
2-vinylfuran (2VF) is a bioderived olefin synthesized by Peterson methylenation of furfural, a cheap platform molecule resulting from acid catalyzed hydrolysis and dehydration of pentosanes from lignocellulosic biomass. Ideal ATR copolymerization of styrene with 2VF yielded random copolymers (S-co-2VFs) in a wide range of composition and high monomer conversion.[1] The S-co-2VFs are stable for years in solution and solid state at room temperature; radical oxidation of the furan moieties starts in air at temperature higher than 120°C whereas thermal degradation occurs at 380°C. Diels Alder (DA) cycloaddition reaction of S-co-2VFs with bismaleimide (BMI) produces thermorevesible crosslinks: the thermodynamic and kinetic parameters of this reaction were investigated by NMR and FT-IR spectroscopy to assess the optimal condition for high crosslink degree and self healing conditions. The mechanical properties of the S-co-2VFs, before and after reaction with BMI, were compared using INSTRON analysis and nanoidentation of polymeric thin films by Atomic Force Microscopy.[2] Moreover simple thermal treatment of mechanically fractured films of S-co-2VFs reacted with BMI allowed full repairing in 80 min (Figure 1).
Scheme. Diels Alder reaction of S-co-2VFs with BMI.
Figure 1. Fractured (a) and healed (b) polymer film of S-co-2VF crosslinked with BMI after thermal annealing at 150°C.
References
[1] S. Ortega Sáncheza, F. Marra, A. Dibenedetto, M. Aresta, A. GrassiMacromolecules 2014, 47, 7129−7137.
[2] A. Grassi, A. Buonerba, C. Capacchione, S. Milione ACS National Meeting San Diego (USA) 2016
Paolo Grassi, Giorgio Strehler e Gerardo Guerrieri, primo "dramaturg" del Piccolo Teatro?
No full textL’articolo ripercorre per sommi capi, anche grazie alla pubblica- zione di alcune lettere inedite e il supporto di documenti d’archivio, la collaborazione e il rapporto di amicizia tra Gerardo Guerrieri, Paolo Grassi e Giorgio Strehler. Guerrieri, oltre che riferimento imprescin- dibile per Grassi e Strehler nella scelta di testi del repertorio ameri- cano, e non solo americano, fu almeno fino a metà anni Cinquanta tra i più attivi consulenti culturali del Piccolo Teatro di Milano, rico- prendo in certi casi funzioni probabilmente assimilabili a quelle di dramaturg
Reply to comments on Grassi et al.: Clinical outcome and complications of a collagen meniscus implant: A systematic review
No full textClinical outcomes and complications of a collagen meniscus implant: a systematic review
Nitrobenzene Reduction with AuNPs supported onto a polymeric matrix
No full textNitrobenzene Reduction with AuNPs supported onto a polymeric matrix
Annarita Noschese1*, Antonio Buonerba1, Carmine Capacchione1,
Stefano Milione1, Alfonso Grassi1
1 - Dipartimento di Chimica e Biologia, Università degli Studi di Salerno, Via Giovanni Paolo II - 84084 Fisciano (SA), Italy, and CIRCC-Bari, Italy
[email protected]
Gold Nanoparticles (AuNPs) are a powerful and versatile catalyst suitable in a variety of oxidation and reduction reactions under sustainable conditions [1]. E.g. aerobic oxidation of alcohols and cross coupling reactions of alcohols to esters, amide, imine have been widely and successfully explored [2]. On the other side the reduction of nitroarenes to anilines using NaBH4, H2, silanes, formic acid, CO/H2O is a benchmark reaction for testing the catalytic performances of AuNPs in reduction reactions [3].
In this scenario, AuNPs embedded in a polymeric matrix consisting of syndiotactic polystyrene-co-cis-1,4-polybutadiene (AuNPs-sPSB) were found extremely active in oxidation catalysis [4]; thus herein we report on the use of the AuNPs-sPSB catalyst in the reduction of nitrobenzene to aniline using NaBH4. The polymorphic behaviour of the host polymer matrix has been studied in order to optimize the catalyst performances. The nanoporous crystalline forms, namely and , of the sPSB matrix allowed a total conversion of nitrobenzene in 40 min at room temperature, with 100% selectivity in aniline. The not permeable crystalline form produced a less reactive and selective catalyst; actually azobenzene and azoxybenzene were detected as intermediates compounds providing information on the cascade of reactions and the global reaction mechanism.
The catalyst is very stable under the reaction conditions and reusable for at least three times without any loss of catalytic activity.
[1] M. Stratakis, H. Garcia, Chem. Rev. 112 (2012). 4469.
[2] A. Corma, H. Garcia, Chem. Soc. Rev. 37 (2008) 2096.
[3] S. Fountoulaki, V. Daikopoulou, P. L. Gkizis, I. Tamiolakis, G.S. Armatas, I. N. Lykakis*, ACS Catal. 4 (2014) 3504; X. Liu, S. Ye, H.-Q. Li, Y.-M. Liu, Y. Cao, K.-N. Fan, Catal. Sci. Technol. 3 (2013) 3200.
[4] A. Buonerba, C. Cuomo, S. Ortega Sánchez, P. Canton, A.Grassi, Chem. Eur. J. 18 (2012) 709 ; A. Buonerba, A. Noschese, A. Grassi, Chem. Eur. J. 20 (2014) 5478
Ambiente e costituzione
No full textL’incontro di studi tenuto dal prof. Stefano Grassi ha inteso vagliare l’attualità del ragionamento circa i principi costituzionali e la loro influenza sulle questioni ambientali.
In particolare si è tentato di tracciare i contorni della nozione, dinamica e relazionale, di ambiente; di stabilire la necessità o meno dell’inserimento del valore ambiente tra i diritti espressamente tutelati dal dettato costituzionale; di individuare i criteri che presiedono al bilanciamento, operato a più livelli (Corte Costituzionale, organi giudiziari, Legislatore e P.A.), tra l’ambiente e i valori concorrenti e/o antagonisti; di evidenziare i problemi e le potenzialità di una governance ambientale multilivello
sj-pdf-1-sph-10.1177_19417381211063450 – Supplemental material for Beyond Distance: A Simple Qualitative Assessment of the Single-Leg Hop Test in Return-to-Play Testing
No full textSupplemental material, sj-pdf-1-sph-10.1177_19417381211063450 for Beyond Distance: A Simple Qualitative Assessment of the Single-Leg Hop Test in Return-to-Play Testing by Stefano Di Paolo, Stefano Zaffagnini, Filippo Tosarelli, Alberto Grassi and Francesco Della Villa in Sports Health: A Multidisciplinary Approach</p
sj-pdf-2-sph-10.1177_19417381211063450 – Supplemental material for Beyond Distance: A Simple Qualitative Assessment of the Single-Leg Hop Test in Return-to-Play Testing
No full textSupplemental material, sj-pdf-2-sph-10.1177_19417381211063450 for Beyond Distance: A Simple Qualitative Assessment of the Single-Leg Hop Test in Return-to-Play Testing by Stefano Di Paolo, Stefano Zaffagnini, Filippo Tosarelli, Alberto Grassi and Francesco Della Villa in Sports Health: A Multidisciplinary Approach</p
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