bluuebunny/crossref_metadata_2025 huggingface dataset:
Le « choix » en économie
Authors: Perrin-Heredia Ana
Published: October 2013

Cet article propose une réflexion sur la notion de « choix » économique tel qu’il est envisagé par les institutions sociales à partir du cas des consommateurs pauvres. Pour cela, l’attention s’est tout d’abord portée sur la manière dont les agents de l’action publique de lutte contre le surendettement cherchent à orienter les conduites économiques des particuliers et définissent le « bon » choix en matière d’économie domestique. En contrepoint, l’ethnographie économique réalisée auprès de certains habitants d’un quartier populaire rend intelligibles les choix économiques des consommateurs les plus pauvres. Elle permet surtout de comprendre la façon dont la contrainte budgétaire tout d’abord, la contrainte sociale ensuite, structurent leurs décisions en matière d’économie domestique, y compris celles qui peuvent, parfois, apparaître contraire aux décisions « rationnelles » promues par les agents des politiques sociales.
Les trajectoires bifurquées de la « Réserve écologique » sud-africaine : d'une logique aménagiste à une logique écologique
Authors: Bourblanc Magalie
Published: October 2013

Avec sa Réserve écologique, la loi sud-africaine de réforme de l’eau de 1998 est considérée aujourd’hui comme pionnière en matière environnementale. Cet engagement a de quoi surprendre dans un pays semi-aride confronté à un défi social majeur – assurer un accès à l’eau plus équitable que sous l’Apartheid pour l’immense majorité de la population noire. Comment l’expliquer ? En faisant un détour par l’histoire, l’auteure met en avant le rôle des ingénieurs civils du ministère de l’Eau dans la création de la Réserve et le rôle qu’ils ont joué dans la stimulation des recherches des hydro-écologues sur le sujet. En recourant au cadre d’analyse de la Critical political ecology , l’article déconstruit les concepts scientifiques en soulignant le caractère anthropocentrique de la Réserve et sa capacité à se fondre dans l’approche managériale du ministère de l’Eau. Il explore ensuite la manière dont la Réserve a évolué vers une dimension plus écologique et sa « confiscation » par les scientifiques à partir de 1998.
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.
Capacité d'adaptation des pratiques traditionnelles de gestion et de partage de l'eau dans l'oasis de Figuig (Maroc)
Authors: Janty Gwenaelle
Published: October 2013

Les oasis se situent en milieux arides ou semi-arides, et la vie végétale et animale ne peut s’y développer que grâce à l’eau et à l’action de l’homme. La gestion de l’eau y mobilise des savoirs, des techniques et des pratiques qui assurent le fonctionnement du système d’irrigation et constituent un élément majeur du patrimoine culturel oasien. La préservation durable de ce patrimoine ne peut s’envisager que si les organisations sociales sont capables de s’adapter via leurs pratiques d’irrigation aux changements environnementaux, conjoncturels ou structurels que connaît l’oasis. Dans cet article sont présentés les savoirs, techniques et pratiques traditionnels liés au système d’irrigation ainsi que les informations de gestion de l’eau nécessaires à son fonctionnement. La maîtrise de ces informations représente un enjeu de pouvoir. Nous verrons comment leur bonne connaissance et leur partage peuvent soutenir le maintien durable de ces savoirs, techniques et pratiques d’irrigation.
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.
Les équivoques de la bipolarité
Authors: David Marielle
Published: October 2013

Le terme bipolaire est devenu pour nombre de sujets un mode d’identité qui, paradoxalement, les rassure car le discours social lui donne une place. Cet article fait l’hypothèse que dans la vie intra-utérine, le placenta déjà mémorisé par le fœtus devient objet perdu. Dans la maniaco-dépression, maladie grave, le sujet qui souffre d’un manque d’amour de l’Autre fait retour à cet objet-cadavre qui tombe sur son moi.
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.
Hystérie ou mélancolie ?
Authors: Godefroy Hélène
Published: October 2013

Cet article a pour but de démontrer que les épisodes soudains de mélancolisation, émergeant en cours d’analyse, peuvent faire douter de la structure du sujet à laquelle nous avons affaire. Hésitant, tout d’un coup, entre une névrose supposée et la possibilité d’une psychose jusque-là occultée, le psychanalyste, surpris par cet effondrement imprévisible qui lui échappe, est confronté à reconsidérer son écoute clinique et la technique à adopter pour reprendre la direction de la cure sans risquer l’échec imminent du traitement.
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.
Why Practices?
Authors: James Aaron
Published: October 2013

Pourquoi les pratiques? La méthode de justification fondée sur les pratiques suppose un certain degré de sensibilité aux pratiques sociales. Cela soulève des questions épineuses : les pratiques en question doivent-elles être établies ou au moins réalistes ? Quel degré de « construction » pouvons-nous assumer lorsque nous interprétons leur forme ou leurs buts ? Cet article suggère que les réponses à ces questions peuvent varier en fonction de nos objectifs explicatifs. Les exigences liées au réalisme et à l’exactitude sociologique sont relativement faibles lorsque ces objectifs sont purement intellectuels et visant la compréhension morale, plus fortes lorsque l’objectif est de déterminer les conditions générales de la vie humaine en collectivité, plus fortes encore lorsque l’objectif est de justifier les principes comme étant normatifs pour nous, étant donnée notre situation actuelle dans l’histoire du monde. Je suggère que nous n’avons pas de raison d’insister sur un ensemble de questions de justice à l’exclusion des autres, même si les exigences normatives occupent à juste titre une place centrale.
Global Justice and Two Conceptions of Practice-Dependence
Authors: Frøslee Malte
Published: October 2013

La justice globale et deux conceptions de la dépendance aux pratiques La dépendance aux pratiques a récemment reçu une attention soutenue en théorie politique, pas seulement pour des raisons méthodologiques, mais aussi en raison de son soutien ostensible à l’étatisme – la position qui veut que la portée des principes de justice soit limitée à l’État-Nation. Cet article vise à réfuter l’affirmation selon laquelle la dépendance aux pratiques conduit nécessairement à l’étatisme. Il distingue deux sens de la dépendance aux pratiques dans les travaux de Rawls afin de clarifier la façon dont l’étatisme découle, non pas de la méthodologie rawlsienne en tant que telle, mais plutôt du genre de pratiques dont sa conception dépend. En distinguant les pratiques fondamentales des pratiques institutionnalisées, nous pouvons identifier une conception de la dépendance aux pratiques, à l’oeuvre dans les travaux de Jürgen Habermas, qui conduit au cosmopolitisme. L’article contraste enfin la critique interne de Rawls concernant l’État-Nation avec la critique externe de Habermas, et se prononce en faveur de cette dernière approche.
Practices, Institutions, and Global Public Good Regimes
Authors: Taylor Isaac
Published: October 2013

Pratiques, institutions, et régimes des biens publiques globaux Une conception de la justice dépendant des pratiques est une conception qui considère que les principes de justice dépendent, dans leur contenu, de la nature des pratiques qu’ils visent à réguler. L’institutionnalisme, une forme de dépendance à la pratique, affirme que c’est la forme institutionnelle qui détermine les principes de justice. Plus précisément, les principes de justice devraient permettre la poursuite effective du but et de l’objet de l’institution qu’ils régulent. Puisqu’il ne peut y avoir, selon cette approche, de principes de justice en l’absence d’institutions, une de ses conséquences est de nier qu’instaurer de nouvelles institutions, lorsqu’elles n’existent pas déjà, soit un devoir de justice. Dans cet article, je plaide à l’encontre de cette dénégation, et prends le cas des biens publics globaux comme un cas exemplaire où il peut y avoir des devoirs de justice d’instaurer de nouvelles institutions.
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

A 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.
Design and testing of a GPS/GSM collar prototype to combat cattle rustling
Authors: Tangorra Francesco M. , Calcante Aldo , Nava Stefano , Marchesi Gabriele , Lazzari Massimo
Published: October 2013

Rustling is an age-old practice that was widespread in Italy until the first half of the 20th century. Today, incidents of cattle rustling are again being reported. However, the problem is not only found in Italy. It is also becoming a plague for ranchers in the US and is still rampant in East Africa. In Italy, the cattle rustling phenomena have usually been limited through the direct control of the herdsmen. Global positioning system (GPS) and geographic information system (GIS) combined technologies are increasingly applied for tracking and monitoring livestock with greater spatial and temporal resolution. However, so far, no case studies of the use of GPS technology to combat cattle rustling have been reported in the literature. The aim of this research was to develop a GPS/GSM (global system for mobile communication) collar, using commercial hardware and implementing a specific software [ARVAshepherd 1.0; ARVAtec Srl, Rescaldina (MI), Italy] to track animals’ movements outside their grazing area and to signal when animals are straying outside virtual perimeters. A phase I study was conducted from January to June 2011 to build the GPS/GSM collar and to assess its performances in terms of GPS accuracy and precision, while a phase II study was conducted in July 2011 to test the GPS collar under real-life operating conditions. The static GPS positioning error achieved a circular error probable (50%) and horizontal 95% accuracy of 1.462 m and 4.501 m, respectively. This is comparable with values obtained by other authors in static tests of a commercial GPS collar for grazing studies. In field tests, the system was able to identify the incorrect position of the cattle and the warning messages were sent promptly to the farmer, continuing until the animals had been repositioned inside the fence, thus highlighting the potential of the GPS/GSM collar as an anti-theft system.
Sequent depth ratio of B-jumps on smooth and rough beds
Authors: Carollo Francesco Giuseppe , Ferro Vito , Pampalone Vincenzo
Published: October 2013

A hydraulic B-jump has the toe section located on a positively sloping upstream channel and the roller end on a downstream horizontal channel. This paper analyses the B-jump on a rough bed, such as at the transition from a block ramp to the stilling basin. Laboratory measurements of the sequent depth were carried out using three different channel slopes for the rough bed and a single slope for the smooth bed. A solution useful for estimating the sequent depth ratio in a rectangular channel for different relative roughness and bed slope is proposed and positively tested by the present measurements. This solution can also be used to estimate the sequent depth ratio of classical hydraulic jumps or B-jumps on smooth and rough beds.
The use of hyperspectral imaging in the visible and near infrared region to discriminate between table grapes harvested at different times
Authors: Piazzolla Francesca , Amodio Maria Luisa , Colelli Giancarlo
Published: October 2013

Traditional analytical methods applied to the measurement of grape maturity and quality index in order to assess optimal harvest time have been proved to be slow and destructive. Therefore, non-destructive analytical techniques, including spectroscopy, can be a valid support for the choice of the best time to harvest. This study evaluated the feasibility of using a visible and near infrared spectral scanner (v. 1.4; DV Srl, Padova, Italy) with a detector in the region between 400-1000 nm to discriminate between grapes harvested at different times. Twelve clusters were harvested at 5 different times between October and December 2011. Spectra were acquired with a Spectral scanner on 3 intact berries from each bunch. These were randomly selected from top, medium and bottom zones, for a total of 180 spectra. Classification models were construed comparing 2 methods: soft independent modelling of class analogy (SIMCA) and partial least squares discriminant analysis (PLS-DA). The SIMCA model was developed building individual principal component analysis (PCA) models for the spectra of each harvest time. Different pre-treatment methods were tested in order to enhance the power of the model, thus enhancing the score differences among samples from different harvest times. The transformation that allowed the best statistical separation among scores of grapes from different harvest times was the second derivate of Norris. Therefore, the PCA model obtained from the spectra subjected to this pre-treatment was used for SIMCA classification. The PLS-DA model were developed applying the PLS2 algorithm. In order to construct discriminant models to classify bunch spectra according to the 5 harvest times, spectral variations were correlated with the 5 categories established. No pretreatments were previously applied in this last case since they did not improve the final result. The SIMCA method was unable to correctly classify grapes from harvest time 2 (59% of correct classification) and was less efficient compared to the PLS-DA model. Using the PLS-DA model, all the grapes were correctly classified (100%) with the exception of those from harvest time 5 (94%). The overall results demonstrate that this method has excellent potential for discriminating grape quality.
Total and high-molecular-weight adiponectin levels in relation to insulin resistance among overweight/obese adults
Authors: Acharya Sushama D. , Evans Rhobert W. , Brooks Maria M. , Linkov Faina , Burke Lora E.
Published: October 2013

Objective: To determine whether baseline levels or intervention-associated changes in total and high molecular weight (HMW) adiponectin levels were associated with insulin resistance after six months of behavioral treatment for weight loss.Design: An ancillary study to a behavioral weight loss trial; the intervention was delivered in group sessions.Methods: Participants included 143 overweight/obese adults with a mean BMI of 33.7 kg/m2. The sample was 88% female, 67% white, and 44.2 ± 8.5 years old. Circulating adiponectin levels (total and HMW) and the homeostasis model assessment (HOMA) of insulin resistance were measured and evaluated.Results: At baseline, there was significant inverse associations between total adiponectin and HOMA (p < 0.001) and between HMW adiponectin and HOMA (p < 0.001) independent of weight. At 6-mo, there was a 17% improvement in HOMA, 8% increase in total adiponectin, 17% increase in HMW adiponectin levels, and 8.72% weight loss (p's for all< 0.001). There was also a significant inverse association between changes in total adiponectin and HOMA (p = 0.04) that was independent of baseline weight and weight loss. In contrast, the association between changes in HMW adiponectin and HOMA was attenuated after adjustment for weight loss.Conclusions: An increased level of total adiponectin was associated with improved insulin sensitivity, regardless of baseline weight and weight loss. However, baseline total and HMW adiponectin levels were more strongly associated with HOMA than changes in these measures at six months. HMW adiponectin level was not related more closely to insulin resistance than total adiponectin level.
Di Baldassarre Receives 2012 Hydrologic Sciences Early Career Award: Response
Authors: Di Baldassarre Giuliano
Published: October 2013

Thank you very much, Alberto, for your nice comments and the precious support you have given me since the very beginning of my scientific career.
Katul Receives 2012 Hydrologic Sciences Award: Citation
Authors: Parlange Marc B.
Published: October 2013

I am delighted to present Professor Gabriel Katul of Duke University with the 2012 Hydrologic Sciences Award. He has made massive contributions to the understanding and prediction of hydrology, and it is for his work that we (Professors Poporato, Hornberger, Rinaldo, Rodriguez‐Iturbe, Brutsaert, and Raupach) nominated him.
Shifts of the Subtropical Shelf Front controlled by atmospheric variations
Authors: Balcerak Ernie
Published: October 2013

In the western South Atlantic, off the coast of South America, a band of cold, fresh, nutrient‐rich Sub‐Antarctic Shelf Water (SASW) meets warm, salty, nutrient‐poor Subtropical Shelf Water (STSW) to form the Subtropical Shelf Front (STSF). This front is the shallow‐water expression of the major Brazil‐Malvinas Confluence Zone and has moved northward and southward during the Holocene (the past ~12,000 years). Bender et al. reconstruct the latitudinal shifts of the STSF over the past 11,000 calendar‐equivalent years using records of oxygen and carbon stable isotope compositions of benthic foraminifera and total organic carbon and calcium carbonate content from a sediment record collected off Uruguay. These measurements serve as proxies for ocean water temperature and nutrient content, which can be used to distinguish the SASW and STSW.
Towards the Rational Design of Efficient Organic Structure‐Directing Agents for Zeolite Synthesis
Authors: Moliner Manuel , Rey Fernando , Corma Avelino
Published: October 2013

Zeolites 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

Sustainable 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

We 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

Aeruginosin‐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

Cytochrome 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

A 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

Ralfuranones 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

Two 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

Metal‐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

The 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

In 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

Novel 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

Plasma‐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.
On the Regio‐ and Stereospecificity of Arachidonic Acid Peroxidation Catalyzed by Mammalian 15‐Lypoxygenases: A Combined Molecular Dynamics and QM/MM Study
Authors: Suardíaz Reynier , Masgrau Laura , Lluch José M. , González‐Lafont Àngels
Published: October 2013

15‐Lipoxygenases (15‐LOs) catalyse the peroxidation reaction of arachidonic acid (AA) in mammals with remarkable regio‐ and stereospecificity. This positional‐specific peroxidation is of paramount importance because it determines the nature and biological functions of the final metabolites generated by each LO as a result of the oxidative metabolism of AA. Although several hypotheses have been formulated concerning the regio‐ and stereospecificity of LOs, the molecular basis of such behaviour is still unclear. Herein, we combined quantum mechanics/molecular mechanics calculations with molecular dynamics simulations of the complete rabbit 15‐LO/AA solvated model to examine the most accepted hypotheses for the regio‐ and stereospecificity of LOs. We have found that the clue to explain this specificity is the oxygen‐targeting hypothesis through steric shielding of specific residues (mainly Leu597, Gln548 and Phe175, as well as the AA tail itself). Our deductions are based primarily on the analysis of the energy barrier heights from the oxygen addition reaction profiles.
Fluorescent Silver Nanoclusters in Condensed DNA
Authors: Volkov Ivan L. , Ramazanov Ruslan R. , Ubyivovk Evgeniy V. , Rolich Valerij I. , Kononov Alexei I. , Kasyanenko Nina A.
Published: October 2013

We study the formation and fluorescent properties of silver nanoclusters encapsulated in condensed DNA nanoparticles. Fluorescent globular DNA nanoparticles are formed using a dsDNA–cluster complex and polyallylamine as condensing agents. The fluorescence emission spectrum of single DNA nanoparticles is obtained using tip‐enhanced fluorescence microscopy. Fluorescent clusters in condensed DNA nanoparticles appear to be more protected against destructive damage in solution compared to clusters synthesized on a linear polymer chain. The fluorescent clusters on both dsDNA and ssDNA exhibit the same emission bands (at 590 and 680 nm) and the same formation efficiency, which suggests the same binding sites. By using density functional theory, we show that the clusters may bind to the Watson–Crick guanine–cytosine base pairs and to single DNA bases with about the same affinity.
Straightforward Oxidation of a Copper Substrate Produces an Underwater Superoleophobic Mesh for Oil/Water Separation
Authors: Liu Na , Chen Yuning , Lu Fei , Cao Yingze , Xue Zhongxin , Li Kan , Feng Lin , Wei Yen
Published: October 2013

A superhydrophilic and underwater superoleophobic Cu(OH)2‐covered mesh with micro‐ and nanoscale hierarchical composite structures is successfully fabricated through a one‐step chemical oxidation of a smooth‐copper mesh. Such mesh, without any further modification, can selectively separate water from oil/water mixtures with high separation efficiency, and possess excellent stability even after 60 uses. This method provides a simple, low‐cost, and scalable strategy for the purification of oily wastewater.
Playing with Structures at the Nanoscale: Designing Catalysts by Manipulation of Clusters and Nanocrystals as Building Blocks
Authors: Cargnello Matteo , Fornasiero Paolo , Gorte Raymond J.
Published: October 2013

The purpose of this Concept is to highlight some of the most recent and promising methods for the preparation of tailored catalysts by designing and preparing the component building blocks and by assembling them in a controlled fashion. We want to emphasize how rational design and synthesis of catalysts must be coupled to precise catalytic and structural characterization of the systems in an ideal feedback loop. New catalyst design and preparation techniques, dictated by information about the active sites that the specific application requires, are frequently available. The building blocks for developing these novel catalysts include colloidal methods for the preparation of uniform nanostructures, physical methods for rational assembly of the building blocks (Langmuir–Blodgett, liquid–air self‐assembly), and development of rational interactions between the building blocks for enhanced activity of the assemblies. These methods, which apply techniques normally used in other fields of nanotechnology to catalysis, offer exciting opportunities to help improve currently available catalytic systems in terms of activity, stability and selectivity.
The response of methane hydrate beneath the seabed offshore Svalbard to ocean warming during the next three centuries
Authors: Marín‐Moreno Héctor , Minshull Timothy A. , Westbrook Graham K. , Sinha Bablu , Sarkar Sudipta
Published: October 2013

Methane is a potent greenhouse gas and large‐scale rapid release of methane from hydrate may have contributed to past abrupt climate change inferred from the geological record. The discovery in 2008 of over 250 plumes of methane gas escaping from the seabed of the West Svalbard continental margin at ~400 m water depth (mwd) suggests that hydrate is dissociating in the present‐day Arctic. Here we model the dynamic response of hydrate‐bearing sediments over a period of 2300 years and investigate ocean warming as a possible cause for present‐day and likely future dissociation of hydrate, within 350–800 mwd, west of Svalbard. Future temperatures are given by two climate models, HadGEM2 and CCSM4, and scenarios, Representative Concentration Pathways (RCPs) 8.5 and 2.6. Our results suggest that over the next three centuries 5.3–29 Gg yr−1 of methane may be released to the Arctic Ocean on the West Svalbard margin.
Flow‐Based, Cerium Oxide Enhanced, Low‐Level Palladium Sonogashira and Heck Coupling Reactions by Perovskite Catalysts
Authors: Battilocchio Claudio , Bhawal Benjamin N. , Chorghade Rajeev , Deadman Benjamin J. , Hawkins Joel M. , Ley Steven V.
Published: October 2013

A flow chemistry procedure for Sonogashira and Heck cross‐coupling reactions using a low‐level palladium perovskite catalyst (LaFe0.95Pd0.05O3) deposited on cerium oxide is reported. The catalyst was generated in situ at high temperature using a flow platform. The system could be applied to a wide range of functionalised substrates, allowing clean and fast delivery of the products within a few minutes (10–30 min), after scavenging with thiourea polymer (QP‐TU) and sulfonic acid resin (QP‐SA). The use of an in‐line evaporator/solvent switching device allowed us to recover the solvent and transport the material into the following stage. The catalyst could be continuously used for at least 24 h, without any noticeable decrease in the catalytic efficiency. In one example the system was scaled to deliver 10 mmol of product.