130 research outputs found
Mechanistic Aspects of the Polymerization of Lactide Using a Highly Efficient Aluminum(III) Catalytic System
No full textbibtex: ISI:000400802300037 bibtex\location:'1155 16TH ST, NW, WASHINGTON, DC 20036 USA',publisher:'AMER CHEMICAL SOC',type:'Article',affiliation:'Thomas, CM (Reprint Author), PSL Res Univ, Chim ParisTech, CNRS, Inst Rech Chim Paris, F-75005 Paris, France. Maron, L (Reprint Author), Univ Toulouse, 135 Ave Rangueil, F-31077 Toulouse, France. Maron, L (Reprint Author), UPS, INSA, 135 Ave Rangueil, F-31077 Toulouse, France. Maron, L (Reprint Author), IRSAMC, LPCNO, 135 Ave Rangueil, F-31077 Toulouse, France. Maron, L (Reprint Author), CNRS, F-31077 Toulouse, France. Maron, L (Reprint Author), IRSAMC, UMR 5215, F-31077 Toulouse, France. Robert, Carine; Schmid, Thibault E.; Richard, Vincent; Haquette, Pierre; Raman, Sumesh K.; Rager, Marie-Noelle; Thomas, Christophe M., PSL Res Univ, Chim ParisTech, CNRS, Inst Rech Chim Paris, F-75005 Paris, France. Gauvin, Regis M.; Morin, Yohann, Univ Lille, Univ Artois, CNRS, Cent Lille,ENSCL,UCCS,UMR 8181, F-59000 Lille, France. Trivelli, Xavier, Univ Lille, CNRS, UGSF, UMR 8576, F-59000 Lille, France. Guerineau, Vincent, Univ Paris Sud, Univ Paris Saclay, CNRS UPR2301, Inst Chim Subst Nat, Ave Terrasse, F-91198 Gif Sur Yvette, France. del Rosal, Iker; Maron, Laurent, Univ Toulouse, 135 Ave Rangueil, F-31077 Toulouse, France. del Rosal, Iker; Maron, Laurent, UPS, INSA, 135 Ave Rangueil, F-31077 Toulouse, France. del Rosal, Iker; Maron, Laurent, IRSAMC, LPCNO, 135 Ave Rangueil, F-31077 Toulouse, France. del Rosal, Iker; Maron, Laurent, CNRS, F-31077 Toulouse, France. del Rosal, Iker; Maron, Laurent, IRSAMC, UMR 5215, F-31077 Toulouse, France.','author-email':'[email protected] [email protected]',da:'2018-12-05','doc-delivery-number':'EU1SV','funding-acknowledgement':'ENSCP; ANR [ANR-10-PDOC-010-01]; Fondation Pierre-Gilles de Gennes; CNRS; CALMIP-EOS [p0833]; CNRS [TGIR-RMN-THC Fr3050]','funding-text':'ENSCP, ANR (grant ANR-10-PDOC-010-01), Fondation Pierre-Gilles de Gennes, and CNRS are thanked for financial support of this work. This work was performed using HPC resources from CALMIP-EOS (grant p0833). We would like to thank Purac for a generous loan of rac-lactide. C.M.T. is grateful to the Institut Universitaire de France (IUF). Financial support from the TGIR-RMN-THC Fr3050 CNRS for conducting the research is gratefully acknowledged.','journal-iso':'J. Am. Chem. Soc.','keywords-plus':'RING-OPENING POLYMERIZATION; CHROMIUM SALEN COMPLEXES; QUATERNARY ORGANIC SALT; CARBON-DIOXIDE; PROPYLENE-OXIDE; RAC-LACTIDE; STEREOSELECTIVE POLYMERIZATION; ALTERNATING COPOLYMERIZATION; CYCLIC CARBONATES; RACEMIC LACTIDE','number-of-cited-references':'85','orcid-numbers':'Del Rosal, Iker/0000-0001-6898-4550 Gauvin, Regis/0000-0002-4788-4363 Guerineau, Vincent/0000-0002-1747-5016 Thomas, Christophe/0000-0001-8014-4255','research-areas':'Chemistry','researcherid-numbers':'Del Rosal, Iker/H-3419-2012','times-cited':'12','unique-id':'ISI:000400802300037','usage-count-last-180-days':'13','usage-count-since-2013':'83','web-of-science-categories':'Chemistry, Multidisciplinary'\International audienceWe report here a unique example of an in situ generated aluminum initiator stabilized by a C-2-symmetric salen ligand which shows a hitherto unknown high activity for the ROP of rac-lactide at room temperature. Using a simple and robust catalyst system, which is prepared from a salen complex and an onium salt, this convenient route employs readily available reagents that afford polylactide in good yields with narrow polydispersity indices, without the need for time-consuming and expensive processes that are typically required for catalyst preparation and purification. In line with the experimental evidence, DFT studies reveal that initiation and propagation proceed via an external alkoxide attack on the coordinated monomer
Première étude structurale et dynamique d'une peroxyrédoxine par RMN
No full textLes cellules luttent en permanence contre les pro-oxydants et leurs effets néfastes. Les hydroperoxydes en sont les plus courants. La cystéine nucléophile du site actif confère aux peroxyrédoxines (Prx) une activité peroxydasique, réductrice des hydroperoxydes dépendante notamment de thiorédoxines. Pour la première fois, une Prx, Ahp1 de Saccharomyces cerevisiae, a fait l'objet d'une étude structurale par RMN triple résonance (1H/13C/15N) sur un échantillon uniformément marqué [13C/15N/50 % 2H] en milieu aqueux réducteur. Sa topologie est semblable à celle des autres Prx. L'analyse des données de relaxation RMN 15N a émontré que Ahp1 est un homodimère 2x19,4kDa en solution, ce qui a été confirmé par ultracentrifugation analytique et par des calculs d'hydrodynamique. La forme suroxydée, préparée in vitro par un excès de tBuOOH, a été cractérisée grâce à un marquage sélectif Cys[b-13C]. Les résultats montrent que la cystéine du site actif est alors oxydée en sulfonateLYON1-BU.Sciences (692662101) / SudocSudocFranceF
Grandes Proyectos Urbanos como instrumento de intervención pública en las ciudades
No full textThe author reflects upon the importance of cities in the development of countries and how they can be intervened. Urban projects are presented from a perspective that goes beyond the city extends and far beyond the interests of the real estate business.El autor invita a reconocer la importancia de las ciudades en el desarrollo de los países, y como tal puede ser intervenida. Se plantean los proyectos urbanos desde una perspectiva más amplia que “la ciudad”, y mucho más allá del negocio inmobiliario
Spontaneous assembly of photosynthetic supramolecular complexes as mediated by the intrinsically unstructured protein CP12
No full textCP12 is a protein of 8.7 kDa that contributes to Calvin cycle regulation by acting as a scaffold element in the formation of a supramolecular complex with glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and phosphoribulokinase (PRK) in photosynthetic organisms. NMR studies of recombinant CP12 (isoform 2) of Arabidopsis thaliana show that CP12-2 is poorly structured. CP12-2 is monomeric in solution and contains four cysteines, which can form two intramolecular disulfides with midpoint redox potentials of -326 and -352 mV, respectively, at pH 7.9. Site-specific mutants indicate that the C-terminal disulfide is involved in the interaction between CP12-2 and GAPDH (isoform A4), whereas the N-terminal disulfide is involved in the interaction between this binary complex and PRK. In the presence of NAD, oxidized CP12-2 interacts with A4-GAPDH(KD = 0.18μM) to form a binary complex of 170 kDa with (A4-GAPDH)-(CP12-2)2 stoichiometry, as determined by isothermal titration calorimetry and multiangle light scattering analysis. PRK is a dimer and by interacting with this binary complex (KD = 0.17 μM) leads to a 498-kDa ternary complex constituted by two binary complexes and two PRK dimers, i.e. ((A4-GAPDH)-(CP12-2)2-(PRK))2. Thermodynamic parameters indicate that assembly of both binary and ternary complexes
is exoergonic although penalized by a decrease in entropy that suggests an induced folding of CP12-2 upon binding to partner proteins. The redox dependence of events leading to supramolecular complexes is consistent with a role of CP12 in coordinating the reversible inactivation of chloroplast enzymes A4-GAPDH and PRK during darkness in photosynthetic tissues
Role and Effects of Credit Information Sharing
No full textInformation sharing about borrowers’ characteristics and their indebtedness can have important effects on credit markets activity. First, it improves the banks’ knowledge of applicants’ characteristics and permits a more accurate prediction of their repayment probabilities. Second, it reduces the informational rents that banks could otherwise extract from their customers. Third, it can operate as a borrower discipline device. Finally, it eliminates borrowers’ incentive to become over-indebted by drawing credit simultaneously from many banks without any of them realizing. This chapter provides a brief account of models that capture these four effects of information sharing on credit market performance, as well as of the growing body of empirical studies that have attempted to investigate the various dimensions and effects of credit reporting activity. Understanding the effects of information sharing also helps to shed light on some key issues in the design of a credit information system, such as the relationship between public and private mechanisms, the dosage between black and white information sharing, and the “memory” of the system. Merging the insights from theoretical models with the lessons of experience, one can avoid serious pitfalls in the design of credit information systems.information sharing, credit markets
β-lactoglobulin unfolding and heat-aggregation at atomistic scale: How NMR associated with SAXS reveal protein structures at atomistic scale
No full textInternational audienc
Consulta Regional sobre la Politica Rural del Banco Interamericano de Desarrollo
No full textThis article is a document of great bibliographical value because it is a search at an international level. It was conducted in Latin-America to review the rural politics of the Inter-American Bank of Development. The author and his collaborators summarize and make short each one of the opinions given by specialists, experts and studious professionals of primary economy within the Inter-American region. This is the reason why the magazine wants to publish this important and interesting essay which completely illustrates us about the importance of socioeconomy.Search, Inter-American Bank of Development, Rural Development, Synthesis., Agribusiness,
Consulta Regional sobre la Politica Rural del Banco Interamericano de Desarrollo
No full textThis article is a document of great bibliographical value because it is a search at an international
level. It was conducted in Latin-America to review the rural politics of the Inter-American
Bank of Development. The author and his collaborators summarize and make short each one of
the opinions given by specialists, experts and studious professionals of primary economy
within the Inter-American region. This is the reason why the magazine wants to publish this
important and interesting essay which completely illustrates us about the importance of socioeconomy
Molecular niobium(V) complexes with mononuclear {Nb1} and dinuclear oxo species {Nb2O} connected through aryl di- or tetra-carboxylate linker
No full textInternational audienceSeveral aryl polycarboxylic ligands (pyromellitic acid, 4,4′-azobenzenedicarboxylic acid and 3,3′,5,5′- azobenzenetetracarboxylic acid) have been used to react with the pentavalent ethoxide niobium(V) precursor Nb(OEt)5. Three new crystalline molecular compounds (1 with pyromellitate, 2 with 4,4′- azobenzenedicarboxylate and 3 with 3,3′,5,5′-azobenzenetetracarboxylate) were isolated from slowcrystallization at room temperature from the mother liquid containing the precursor Nb(OEt)5. They are composed of one polycarboxylate ligand fully coordinated to mononuclear or dinuclear octahedrally- coordinated niobium(V) units. For the dimers, the two adjacent niobium centers are bridged by one μ-O and one μ-OEt groups and complexed by only one of the syn–syn bidentate carboxylate function arms from the polytopic ligand. Compounds 1–3 were characterized in solid state by single-crystal and powder X-ray diffraction analysis. Insight into the formation of the three compounds was supported by the help of infrared and liquid 1H NMR spectroscopy.Plusieurs ligands aryl polycarboxyliques (acide pyromellitique, acide 4,4′-azobenzènedicarboxylique et acide 3,3′,5,5′-azobenzènetétracarboxylique) ont été utilisés pour réagir avec l'éthoxyde pentavalent niobium(V) précurseur Nb(OEt)5. Trois nouveaux composés moléculaires cristallins (1 avec du pyromellitate, 2 avec du 4,4′-azobenzènedicarboxylate et 3 avec du 3,3′,5,5′-azobenzènetétracarboxylate) ont été isolés à partir decristallisation à température ambiante à partir du liquide mère contenant le précurseur Nb(OEt)5. Ils sont composés d'un ligand polycarboxylate entièrement coordonné à des unités de niobium (V) octaédriquement coordonnées mononucléaires ou dinucléaires. Pour les dimères, les deux centres de niobium adjacents sont pontés par un groupe μ-O et un groupe μ-OEt et complexés par un seul des bras de la fonction carboxylate syn – syn bidentate du ligand polytopique. Les composés 1 à 3 ont été caractérisés à l'état solide par analyse par diffraction des rayons X sur monocristal et sur poudre. La compréhension de la formation des trois composés a été étayée par l'aide de la spectroscopie RMN 1H infrarouge et liquide
Influence of the pH on the Condensation of Tetravalent Cerium Cations in Association with [α-SiW9O34]10- Leading to the Formation of a Ce6O4 (OH)4 Core
No full textInternational audienc
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