bluuebunny/crossref_metadata_2025_split huggingface dataset:
Aménager l'espace, canaliser l'eau et orienter le pouvoir. Réflexion sur deux modèles inédits d'aménagements fonciers radioconcentriques en France et au Maroc
Authors: Récalt Christine , Rouvière Lôra , Mahdane Mhamed , Errahj Mustafa , Ruf Thierry 
Published: October 2013

L’étang de Montady, desséché au Moyen âge, a tardivement été remodelé par l’irrigation. Cette expérience historique perdure plus de sept siècles après sa fondation, en se fondant sur des savoirs spécifiques et des institutions communautaires basées sur des initiatives locales et privées, mais de plus en plus articulées avec les politiques publiques de l’État français. Parallèlement, les trames radioconcentriques étudiées dans le Saïss au Maroc peuvent être rapprochées du dispositif radioconcentrique de Montady, même si les savoirs techniques et les institutions créées sont au départ l’émanation d’un modèle étatique de réforme agraire. Il n’y a aucune preuve d’un quelconque mimétisme entre les deux exemples, mais des éléments leur sont communs : la défense de leur singularité dans l’environnement immédiat et le besoin de maintenir une certaine cohésion autour du phénomène radioconcentrique.
De la mélancolie dans la psychiatrie classique : en jeu des débats
Authors: Douville Olivier 
Published: October 2013

Cet article expose la naissance et la fabrication de la notion de psychose maniaco-dépressive dans l’histoire de la psychiatrie classique, à partir de Pinel. Différentes étapes sont décrites : la théorie des passions, la monomanie triste, la folie dite «circulaire», la mélancolie et le délire de Cotard, la folie maniaco-dépressive, enfin. Il en ressort que jamais la mélancolie ne fut étudiée, que jamais non plus on ne voulut la soigner, sans articuler cette affection à un autre pôle, qui sera celui de la manie, de la stupeur, et encore de la persécution. La mélancolie a été certes envisagée comme un trouble de l’humeur, mais beaucoup de médecins psychiatres de la psychiatrie classique ont fait une grande place à toute la dimension d’une subjectivité prise dans le rapport à l’Autre. D’où l’importance des moments de persécution, ou des phénomènes d’auto-accusation. Il en ressort que la mélancolie située ainsi ne saurait se réduire à une clinique de l’humeur.
Hétérogénéité des troubles bipolaires
Authors: Gay Christian 
Published: October 2013

Le trouble bipolaire, tel qu’il est défini aujourd’hui, concerne 3 à 5 % de la population générale. La symptomatologie est extrêmement polymorphe et son évolution est très variable. Poser le diagnostic de trouble bipolaire implique de préciser le type de trouble, d’identifier la séquence évolutive et la polarité dominante, ainsi que la personnalité sous-jacente. L’âge de début précoce et l’existence d’antécédents familiaux constituent des index de prédiction de l’effet thérapeutique. La fréquence des comorbidités et des addictions peut justifier des mesures thérapeutiques spécifiques.
Chaïm Soutine : la mélancolie du « dernier peintre maudit »
Authors: Juranville Anne 
Published: October 2013

Il s’agit de montrer ce que la peinture, somptueuse mais excessive et dérangeante, de Chaïm Soutine doit à sa subjectivité mélancolique. On aborde la démesure alors présente à partir de l’opposition formulée par Romano Guardini entre une « bonne mélancolie » – éthique et tragique, au principe de la création – et une « mauvaise mélancolie », pathologique, porteuse de violence autodestructrice. En s’appuyant sur son œuvre, on tente de montrer que la bascule entre ces deux versants extrêmes a pour ressort le statut équivoque du traumatisme tel qu’il est lié chez Soutine à une scène d’enfance elle-même surdéterminée.
Les déterminants de l'accès et des usages d'internet en Afrique Subsaharienne
Authors: Tamokwe Piaptie Georges Bertrand 
Published: October 2013

À partir de données issues d’une enquête au Cameroun, cet article montre que les principaux déterminants favorisant l’accès à Internet en Afrique subsaharienne sont : le genre masculin, un jeune âge, un niveau d’études élevé, le fait d’avoir un parent à l’étranger et un grand nombre d’internautes dans son voisinage social, la possession d’un téléphone portable, l’aptitude à lire et parler l’anglais, l’aptitude à utiliser un logiciel de traitement de texte ou un tableur et l’aptitude à installer un logiciel. Il apparaît que les Camerounais utilisent principalement les services d’Internet liés à la communication et à la recherche d’informations. Ces usages sont surtout freinés par l’âge avancé et favorisés par l’acquisition de compétences en programmation informatique. En conséquence, pour augmenter son efficacité potentielle, une politique de développement des TIC doit reposer sur trois piliers au minimum : la formation classique, la formation professionnelle dans les métiers d’Internet et l’incitation pour la concurrence entre les fournisseurs d’accès Internet.
TGF-β: Guardian of T Cell Function
Authors: Oh Soyoung A. , Li Ming O. 
Published: October 2013

AbstractA fundamental aspect of the adaptive immune system is the generation and maintenance of a diverse and self-tolerant T cell repertoire. Through its regulation of T cell development, homeostasis, tolerance, and differentiation, the highly evolutionarily conserved cytokine TGF-β critically supports a functional T cell pool. The pleiotropic nature of this regulation is likely due to the elaborate control of TGF-β production and activation in the immune system, and the intricacy of TGF-β signaling pathways. In this review we discuss the current understanding of TGF-β regulation of T cells.
Towards the Rational Design of Efficient Organic Structure‐Directing Agents for Zeolite Synthesis
Authors: Moliner Manuel , Rey Fernando , Corma Avelino 
Published: October 2013

AbstractZeolites are crystalline microporous materials with application in diverse fields, especially in catalysis. The ability to prepare zeolites with targeted physicochemical properties for a specific catalytic application is a matter of great interest, because it allows the efficiency of the entire chemical process to be increased (higher product yields, lower undesired by‐products, less energy consumption, and cost savings, etc). Nevertheless, directing the zeolite crystallization towards the material with the desired framework topology, crystal size, or chemical composition is not an easy task, since several variables influence the nucleation and crystallization processes. The combination of accumulated knowledge, rationalization, and innovation has allowed the synthesis of unique zeolitic structures in the last few years. This is especially true in terms of the design of organic and inorganic structure‐directing agents (SDAs). In this Minireview we will present the rationale we have followed in our studies to synthesize new zeolite structures, while putting this in perspective with the advances made by other researchers of the zeolite community.
Keratin–polyhydroxyalkanoate melt‐compounded composites with improved barrier properties of interest in food packaging applications
Authors: Pardo‐Ibáñez Pablo , Lopez‐Rubio Amparo , Martínez‐Sanz Marta , Cabedo Luis , Lagaron José María 
Published: October 2013

ABSTRACTSustainable biocomposite materials based on the combination of polyhydroxyalkanoates with a keratin additive derived from poultry feathers were successfully developed via melt compounding. Suitable dispersions for low loadings of the additive in the biopolymeric matrix were achieved by the melt‐mixing technique. A good physical interaction between the polymeric matrix and the additive was observed by scanning electron microscopy (SEM). Reductions in water, limonene, and oxygen permeability of the pure polymer to less than a half of its initial value for the composite containing 1 wt % of keratin additive were achieved. This composition was also found to exhibit optimum mechanical performance. As a result, these materials offer significant potential in fully renewable packaging applications based on polyhydroxyalkanoates with enhanced barrier performance. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2014,131, 39947.
Iron‐ and Bismuth‐Catalyzed Asymmetric Mukaiyama Aldol Reactions in Aqueous Media
Authors: Kitanosono Taku , Ollevier Thierry , Kobayashi Shū 
Published: October 2013

AbstractWe have developed asymmetric Mukaiyama aldol reactions of silicon enolates with aldehydes catalyzed by chiral FeII and BiIII complexes. Although previous reactions often required relatively harsh conditions, such as strictly anhydrous conditions, very low temperatures (−78 °C), etc., the reactions reported herein proceeded in the presence of water at 0 °C. To find appropriate chiral water‐compatible Lewis acids for the Mukaiyama aldol reaction, many Lewis acids were screened in combination with chiral bipyridine L1, which had previously been found to be a suitable chiral ligand in aqueous media. Three types of chiral catalysts that consisted of a FeII or BiIII metal salt, a chiral ligand (L1), and an additive have been discovered and a wide variety of substrates (silicon enolates and aldehydes) reacted to afford the desired aldol products in high yields with high diastereo‐ and enantioselectivities through an appropriate selection of one of the three catalytic systems. Mechanistic studies elucidated the coordination environments around the FeII and BiIII centers and the effect of additives on the chiral catalysis. Notably, both Brønsted acids and bases worked as efficient additives in the FeII‐catalyzed reactions. The assumed catalytic cycle and transition states indicated important roles of water in these efficient asymmetric Mukaiyama aldol reactions in aqueous media with the broadly applicable and versatile catalytic systems.
Novel Aeruginosin‐865 from Nostoc sp. as a Potent Anti‐inflammatory Agent
Authors: Kapuścik Aleksandra , Hrouzek Pavel , Kuzma Marek , Bártová Simona , Novák Petr , Jokela Jouni , Pflüger Maren , Eger Andreas , Hundsberger Harald , Kopecký Jiří 
Published: October 2013

AbstractAeruginosin‐865 (Aer‐865), isolated from terrestrial cyanobacterium Nostoc sp. Lukešová 30/93, is the first aeruginosin‐type peptide containing both a fatty acid and a carbohydrate moiety, and is the first aeruginosin to be found in the genus Nostoc. Mass spectrometry, chemical and spectroscopic analysis as well as one‐ and two‐dimensional NMR and chiral HPLC analysis of Marfey derivatives were applied to determine the peptidic sequence: D‐Hpla, D‐Leu, 5‐OH‐Choi, Agma, with hexanoic and mannopyranosyl uronic acid moieties linked to Choi. We used an AlphaLISA assay to measure the levels of proinflammatory mediators IL‐8 and ICAM‐1 in hTNF‐α‐stimulated HLMVECs. Aer‐865 showed significant reduction of both: with EC50 values of (3.5±1.5) μg mL−1 ((4.0±1.7) μM) and (50.0±13.4) μg mL−1 ((57.8±15.5) μM), respectively. Confocal laser scanning microscopy revealed that the anti‐inflammatory effect of Aer‐865 was directly associated with inhibition of NF‐κB translocation to the nucleus. Moreover, Aer‐865 did not show any cytotoxic effect.
Cluster Screening: An Effective Approach for Probing the Substrate Space of Uncharacterized Cytochrome P450s
Authors: von Bühler Clemens , Le‐Huu Priska , Urlacher Vlada B. 
Published: October 2013

AbstractCytochrome P450 monooxygenases (P450s) are versatile enzymes with high potential for biocatalysis. The number of newly annotated P450 genes has been increasing constantly, and these thus represent a rich resource for new biocatalysts. However, the substrate scopes of newly identified P450s are often not known, and thus their exploitation is difficult. Herein we describe an approach, named “cluster screening”, and its application for the primary characterization of two P450s: CYP154E1 and CYP154A8. A library comprising 51 compounds was designed and organized into nine groups according to their chemical properties. The activities of both P450s in vitro were maintained with suitable nonphysiological redox partners, and the cluster library was screened with these enzymes for product formation. From this library, 30 compounds tested positive for CYP154E1 and 23 were positive for CYP154A8. Cluster screening distinguishes subtle differences in activity and selectivity of enzymes as closely related as those of the same P450 family. For example, the alkaloid pergolide mesylate was converted by CYP154E1 (4 %) but not by CYP154A8. A building block of vitamin D3, Grundmann's ketone, was converted by both enzymes, although conversion was higher with CYP154E1 (100 vs 53 %).
Chemical and Structural Insights into the Regioversatility of the Aminoglycoside Acetyltransferase Eis
Authors: Houghton Jacob L. , Biswas Tapan , Chen Wenjing , Tsodikov Oleg V. , Garneau‐Tsodikova Sylvie 
Published: October 2013

AbstractA recently discovered cause of tuberculosis resistance to a drug of last resort, the aminoglycoside kanamycin, results from modification of this drug by the enhanced intracellular survival (Eis) protein. Eis is a structurally and functionally unique acetyltransferase with an unusual capability of acetylating aminoglycosides at multiple positions. The extent of this regioversatility and its defining protein features are unclear. Herein, we determined the positions and order of acetylation of five aminoglycosides by NMR spectroscopy. This analysis revealed unprecedented acetylation of the 3′′‐amine of kanamycin, amikacin, and tobramycin, and the γ‐amine of the 4‐amino‐2‐hydroxybutyryl group of amikacin. A crystal structure of Eis in complex with coenzyme A and tobramycin revealed how tobramycin can be accommodated in the Eis active site in two binding modes, consistent with its diacetylation. These studies, describing chemical and structural details of acetylation, will guide future efforts towards designing aminoglycosides and Eis inhibitors to overcome resistance in tuberculosis.
Ralfuranone Thioether Production by the Plant Pathogen Ralstonia solanacearum
Authors: Pauly Julia , Spiteller Dieter , Linz Jeanine , Jacobs Jonathan , Allen Caitilyn , Nett Markus , Hoffmeister Dirk 
Published: October 2013

AbstractRalfuranones are aryl‐substituted furanone secondary metabolites of the Gram‐negative plant pathogen Ralstonia solanacearum. New sulfur‐containing ralfuranone derivatives were identified, including the methyl thioether‐containing ralfuranone D. Isotopic labeling in vivo, as well as headspace analyses of volatiles from R. solanacearum liquid cultures, established a mechanism for the transfer of an intact methylthio group from L‐methionine or α‐keto‐γ‐methylthiobutyric acid. The methylthio acceptor molecule ralfuranone I, a previously postulated biosynthetic intermediate in ralfuranone biosynthesis, was isolated and characterized by NMR. The highly reactive Michael acceptor system of this intermediate readily reacts with various thiols, including glutathione.
The ATP/ADP Substrate Specificity Switch between Toxoplasma gondii NTPDase1 and NTPDase3 is Caused by an Altered Mode of Binding of the Substrate Base
Authors: Krug Ulrike , Totzauer Robert , Zebisch Matthias , Sträter Norbert 
Published: October 2013

AbstractTwo nucleoside triphosphate diphosphohydrolase isoforms (NTPDase1 and NTPDase3) are responsible for the hydrolysis of nucleotides by the intracellular protozoan Toxoplasma gondii. They constitute about 3 % of the total parasite protein. Despite sharing 97 % sequence identity they exhibit opposite ATP versus ADP substrate discrimination ratios. Here we show by mutagenesis that the residues G492/G493 in NTPDase3 and R492/E493 in NTPDase1 are predominantly responsible for the differences in substrate specificity. Crystal structures of NTPDase1 in complexation with analogues of ATP and ADP reveal that the inverted substrate specificity of NTPDase1 relative to NTPDase3 is achieved by switching from the canonical substrate binding mode to a very different alternative one. Instead of being stacked on top of a helix of the C‐terminal domain the nucleotide base is positioned in the interdomain space between the side chains of R108 and R492, recruited from both domains. Furthermore, we show that the NTPDase1 substrate specificity is mainly dependent on the presence of the side chain of E493, which causes repositioning of the ribose component of the nucleotide. All in all, binding by the flexible side chains in the alternative binding mode in NTPDase1 allows for equally good positioning of ATP and ADP with increased activity toward ADP relative to what is seen in the case of NTPDase3.
Oxygen Reduction Reaction Studies of Phosphorus and Nitrogen Co‐Doped Mesoporous Carbon Synthesized via Microwave Technique
Authors: Nasini Udaya B. , Gopal Bairi Venu , Kumar Ramasahayam Sunil , Bourdo Shawn E. , Viswanathan Tito , Shaikh Ali U. 
Published: October 2013

AbstractMetal‐free mesoporous P and N co‐doped carbon (PNDC) composites are evaluated for their electrocatalytic activity towards the oxygen reduction reaction (ORR). Carbonization of melamine and hexamine‐modified tannin in the presence of polyphosophoric acid produces PNDCs with prominent oxygen reduction properties in alkaline media. The effect of the P and N content in the carbon material is evaluated in terms of the ORR activity. The compound containing a high amount of N (8.3 atom %) and P (6.8 atom %), denoted PNDC‐1, shows high electrocatalytic activity, stability, durability, and selectivity towards the ORR. PNDC‐1 has an onset potential of 0.10 V versus a reversible hydrogen reference electrode and shows a significantly improved performance in comparison to the carbon materials containing less P and N dopant atoms. PNDCs exhibit superior ORR current densities to that of the 20 % Pt/C catalyst because of the synergetic effect of P and N co‐doping. X‐ray photoelectron spectroscopy studies indicate the presence of pyridinic and graphitic N species, which are responsible for oxygen reduction that results in higher current densities. Rotating disk electrode and rotating ring‐disk electrode studies support a four electron oxygen reduction to water, with negligible generation of hydrogen peroxide.
Influence of the Particle Size Distribution on the Activity and Selectivity of Carbon‐Supported Platinum Nanoparticle Catalysts for Ethanol Electrooxidation
Authors: Gomes JanainaF. , Profeti Demetrius , Deiner L. Jay 
Published: October 2013

AbstractThe electrooxidation of 0.1 M ethanol in 0.5 M HClO4 is studied with differential electrochemical mass spectrometry (DEMS) and cyclic voltammetry (CV) over two different carbon‐supported platinum‐nanoparticle catalysts (20 wt % metal). As documented by transmission electron microscopy (TEM), the catalysts have similar mean particle sizes but different particle size distributions. One catalyst is composed almost entirely (>99 %) of particles less than or equal to 3.5 nm while a significant fraction (21 %) of the other catalyst is composed of particles larger than 3.5 nm. The presence of the larger particles increases the peak oxidation current density by 116 % (from 0.06 to 0.13 mA cm−2). However, the presence of the larger particles reduces the efficiency for complete ethanol electrooxidation to CO2 from 13 % to 6.4 % over the full potential sweep. These differences in activity and selectivity of the two catalysts are discussed in the context of previously established changes in the bonding strength of reaction intermediates as a function of the catalyst particle size.
PM‐IRRA Spectroelectrochemistry of Hexacyanoferrate Films in Layer‐by‐Layer Polyelectrolyte Multilayers
Authors: Villalba Matías , Méndez De Leo Lucila P. , Calvo Ernesto J. 
Published: October 2013

AbstractIn situ polarization modulation infrared reflection absorption spectroscopy (PM‐IRRAS) under potential control is used to study self‐assembled layer‐by‐layer (LbL) poly(allylamine) (PAH) and poly(acrylic acid) (PAA) multilayers containing the hexacyanoferrate redox system on conductive substrates. Two systems were examined, which differ in the way the redox complex is entrapped in the LbL polyelectrolyte multilayer: In system I, the LbL polyelectrolyte multilayer, self‐assembled by alternate immersion in PAH and PAA, was exchanged in a 2 mm K3Fe(CN)6 solution of pH 3.5 for 30 min and then thoroughly rinsed with water. In system II, the 2 mm K3Fe(CN)6 solution was complexed with PAA prior to self‐assembly with PAA. PM‐IRRAS studies demonstrate the potential dependence of the vibrational modes of the polyelectrolyte backbones and the CN stretching modes, which are sensitive to the redox charge in the iron center.
Synthesis and Properties of Alkoxy‐ and Alkenyl‐Substituted Peralkylated Imidazolium Ionic Liquids
Authors: Maton Cedric , Brooks Neil R. , Van Meervelt Luc , Binnemans Koen , Schaltin Stijn , Fransaer Jan , Stevens Christian V. 
Published: October 2013

AbstractNovel peralkylated imidazolium ionic liquids bearing alkoxy and/or alkenyl side chains have been synthesized and studied. Different synthetic routes towards the imidazoles and the ionic liquids comprising bromide, iodide, methanesulfonate, bis(trifluoromethylsulfonyl)imide ([NTf2]−), and dicyanamide {[N(CN)2]−} as the anion were evaluated, and this led to a library of analogues, for which the melting points, viscosities, and electrochemical windows were determined. Incorporation of alkenyl moieties hindered solidification, except for cations with high symmetry. The alkoxy‐derivatized ionic liquids are often crystalline; however, room‐temperature ionic liquids (RTILs) were obtained with the weakly coordinating anions [NTf2]− and [N(CN)2]−. For the viscosities of the peralkylated RTILs, an opposite trend was found, that is, the alkoxy derivatives are less viscous than their alkenyl‐substituted analogues. Of the crystalline compounds, X‐ray diffraction data were recorded and related to their molecular properties. Upon alkoxy substitution, the electrochemical cathodic limit potential was found to be more positive, whereas the complete electrochemical window of the alkenyl‐substituted imidazolium salts was shifted to somewhat more positive potentials.
Rotational and Translational Dynamics of Ras Proteins upon Binding to Model Membrane Systems
Authors: Werkmüller Alexander , Triola Gemma , Waldmann Herbert , Winter Roland 
Published: October 2013

AbstractPlasma‐membrane‐associated Ras proteins typically control signal transduction processes. As nanoclustering and membrane viscosity sensing provide plausible signaling mechanisms, determination of the rotational and translational dynamics of membrane‐bound Ras isoforms can help to link their dynamic mobility to their function. Herein, by using time‐resolved fluorescence anisotropy and correlation spectroscopic measurements, we obtain the rotational‐correlation time and the translational diffusion coefficient of lipidated boron‐dipyrromethene‐labeled Ras, both in bulk Ras and upon membrane binding. The results show that the second lipidation motif of N‐Ras triggers dimer formation in bulk solution, whereas K‐Ras4B is monomeric. Upon membrane binding, an essentially free rotation of the G‐domain is observed, along with a high lateral mobility; the latter is essentially limited by the viscosity of the membrane and by lipid‐mediated electrostatic interactions. This high diffusional mobility warrants rapid recognition–binding sequences in the membrane‐bound state, thereby facilitating efficient interactions between the Ras proteins and scaffolding or effector proteins. The lipid‐like rapid lateral diffusion observed here complies with in vivo data.