Hydrogen bonding as a clustering agent in protic ionic liquids: like-charge vs opposite-charge dimer formation

The local structure of a series of homologous protic ionic liquids (PILs) is investigated using ab initio computations and ab initio-based molecular dynamics. The purpose of this work is to show that in PILs the network of hydrogen bonds may promote like-charge clustering between anionic species. We correlate the theoretical evidence of this possibility with viscosity experimental data. The homologous series of liquids is obtained by coupling choline with amino acid anions and varying the side chain. We find that the frictional properties of the liquids are clearly connected to the ability of the side chain to establish additional hydrogen bonds (other than the trivial cation–anion interaction). We also show that the large variation of bulk properties along the series of compounds can be explained by assuming that one of the sources of friction in the bulk liquid is the like-charge interaction between anions

Cholinium amino acid-based ionic liquids

Boosted by the simplicity of their synthesis and low toxicity, cholinium and amino acid-based ionic liquids have attracted the attention of researchers in many different fields ranging from computational chemistry to electrochemistry and medicine. Among the uncountable IL variations, these substances occupy a space on their own due to their exceptional biocompatibility that stems from being entirely made by metabolic molecular components. These substances have undergone a rather intensive research activity because of the possibility of using them as greener replacements for traditional ionic liquids. We present here a short review in the attempt to provide a compendium of the state-of-the-art scientific research about this special class of ionic liquids based on the combination of amino acid anions and cholinium cations

Processus politiques et débats associés à la taxation des boissons sucrées en santé publique : du cas français à la situation canadienne

Parmi d’autres interventions visant à promouvoir une saine alimentation et prévenir les maladies chroniques, la taxation des boissons sucrées est recommandée et près de 50 juridictions à travers le monde l’ont adoptée au cours des 15 dernières années. Pourtant, cette mesure reste controversée. Après une introduction sur le concept de taxe nutritionnelle, le 1er chapitre de cette thèse analyse la pertinence d’une taxation des boissons sucrées en santé publique, puis les chapitres 2 et 3 approfondissent les processus politiques et débats associés à cette mesure dans deux pays : la France, où une taxe a été adoptée, et le Canada, où les discussions se poursuivent. Adapté d’un ouvrage publié en 2016, le 1er chapitre est une synthèse de connaissances intégrant des données issues de multiples disciplines dans un cadre d’analyse en 3 volets (bien-fondé, effets potentiels, applicabilité). Tout en pointant les aspects devant être davantage évalués, l’analyse indique qu’une taxation des boissons sucrées pourrait faire partie d’un éventail de politiques nutritionnelles, y compris au Canada. Une consommation excessive de ces boissons est associée à un risque accru de gain de poids, de carie dentaire et de diabète de type 2. Les taxes qui les visent tendent à générer des hausses de prix qui, lorsqu’elles sont significatives (≥ 10%), sont généralement suivies de baisses d’achat. Dans certains cas, cette mesure pourrait aussi encourager les fabricants à réduire la teneur en sucres de leurs produits. La taxation des boissons sucrées est également un moyen de générer des recettes. Son acceptabilité par le public, plutôt faible, tend à augmenter si ces revenus sont réinvestis au bénéfice de la population. Toutefois, taxer les boissons sucrées soulève des préoccupations éthiques, d’équité, de faisabilité juridique et d’acceptabilité politique dépendantes du contexte. Le 2ème chapitre met l’accent sur l’importance d’analyser le processus d’élaboration d’une « taxe soda », puisqu’il sous-tend sa conception, son éventuelle adoption et ses effets potentiels. Il existe peu d’études en la matière. L’étude du cas français (2005-2012) s’appuie sur une recension d’articles de presse et de documents institutionnels ainsi que sur une analyse thématique guidée par la théorie des courants multiples de Kingdon. Elle met en évidence plusieurs conditions ayant contribué à ouvrir une « fenêtre politique » en 2011: l'annonce a été faite par le gouvernement dans un contexte de déficits budgétaires importants ; des scénarios de taxe avaient été élaborés par le passé ; le projet de loi a été appuyé par des politiciens convaincus. Ensuite, diverses conditions (réaction vive mais désorganisée de l'industrie, intérêt des députés pour les recettes générées) ont favorisé l’adoption de la taxe, mais au détriment de sa finalité initiale de santé publique. Tenant compte de la littérature internationale, la discussion identifie divers facteurs pouvant éclairer les acteurs de santé publique souhaitant influencer le processus d’élaboration d’une « taxe soda ». Le 3ème chapitre se penche sur la situation canadienne. Afin d’explorer en quoi le débat public a pu freiner l’élaboration d’une taxation des boissons sucrées ces dernières années, une analyse de cadrage dans la presse écrite (2007-2016) a permis d’apprécier le poids respectif des positions pro- et antitaxation, le type d’acteurs qui en sont à l’origine et leurs argumentaires. Une recherche d’articles de presse a conduit au recensement de 762 positions. Les résultats mettent en évidence un nombre de positions plus important en 2016 (n=234), à l’échelle fédérale (n=267) et au Québec (n=254). Les « pics de positions » mensuels (n ≥ 10) dans ces deux juridictions révèlent un portage politique limité, un contexte politique et économique peu favorable, et des efforts de plaidoyer d’organisations « prosanté » qui n’ont pas semblé réunir le soutien suffisant pour faire basculer le débat en leur faveur. Advenant l’ouverture d’une « fenêtre politique », cette étude apporte un éclairage sur des éléments de cadrage susceptibles de « résonner » dans le débat public tout en étant compatibles avec les données probantes les plus prometteuses quant à la pertinence d’une telle taxe. Finalement, la conclusion intègre les enseignements des trois chapitres en soulignant l’intérêt d’avoir mobilisé différentes perspectives théoriques et disciplinaires, résume les conditions qui influencent l’élaboration d’une « taxe soda », et revient sur les enjeux d’une telle recherche pour soutenir les processus de décision.Among other interventions aimed to promote healthy eating and prevent chronic diseases, sugarsweetened beverage taxation has been recommended and nearly 50 jurisdictions around the world have adopted such a tax over the past 15 years. However, this measure remains controversial. After an introduction on the concept of health-related food taxation, the first chapter of this thesis analyses the relevance of taxing soda for public health, then chapters 2 and 3 focus on the political processes and debates associated with this measure in two countries: France, where a tax has been adopted, and Canada, where discussions are still ongoing. Adapted from a book published in 2016, Chapter 1 is a knowledge synthesis integrating data from multiple disciplines into a three-part analytical framework (rationale, potential effects, applicability). While identifying areas for further evaluation, the analysis indicates that sugar-sweetened beverage taxation could be part of a portfolio of nutrition-enhancing policies, including in Canada. Excessive consumption of these drinks is associated with an increased risk of weight gain, dental caries and type 2 diabetes. Taxing sugar-sweetened beverages tends to generate price increases which, when significant (≥ 10%), are generally followed by purchase reductions. In some cases, this measure could also encourage manufacturers to reduce the sugar content of their products. Soda taxation is also a way to generate revenue. Its acceptability to the public, which is rather low, tends to increase if these revenues are reinvested for the benefit of the population. However, soda taxes raise ethical and equity concerns, legal feasibility challenges and political acceptability issues, depending on the context. Chapter 2 emphasizes the importance of analyzing the policy process of a soda tax, as it underlies its design, possible adoption and potential effects. There are few studies on this subject. The French case study (2005-2012) is based on a review of press articles and institutional documents as well as a thematic analysis guided by Kingdon's multiple streams theory. It highlights several conditions that contributed to opening a "policy window" in 2011: the announcement made by the government occurred in the context of severe budgetary deficits; tax scenarios had been developed in the past; the bill was supported by convinced political leaders. Then, various conditions (strong but disorganized reaction from the industry, interest of Deputies in the revenues generated) favoured the adoption of the tax, but to the detriment of its initial public health purpose. Taking into account the international literature, the discussion identifies various factors that may inform public health actors wishing to influence soda tax policy processes. Chapter 3 focuses on the Canadian situation. In order to explore how the public debate may have hindered the elaboration of a soda tax in recent years, a framing analysis of the topic in the media was conducted (2007-2016) to assess the respective weight of pro- and anti-taxation positions, the type of actors they originate from and their arguments. A total of 762 positions have been identified from the review of press articles. The results show a larger number of positions in 2016 (n=234), at the federal level (n=267) and in Quebec (n=254). The monthly "peaks of positions" (n ≥ 10) in these two jurisdictions reveal limited political support, an unfavourable political and economic context, and advocacy efforts by "pro-health" organizations that did not seem to gather sufficient support to shift the debate in their favour. Should a "policy window" open, this study sheds light on framing elements that may "resonate" in the public debate while being compatible with the most promising evidence regarding the relevance of such a tax. Finally, the conclusion integrates lessons from the three chapters, emphasizes the interest of having mobilized various theoretical and disciplinary perspectives, summarizes key conditions influencing the elaboration of a soda tax, and discusses how such a research may contribute to inform decisionmaking processes

Soda Taxes: The Importance of Analysing Policy Processes Comment on “The Untapped Power of Soda Taxes: Incentivising Consumers, Generating Revenue, and Altering Corporate Behaviours”

Abstract Sarah A. Roache and Lawrence O. Gostin’s recent editorial comprehensively presents soda taxation rationales from a public health perspective. While we essentially agree that soda taxes are gaining momentum, this commentary expands upon the need for a better understanding of the policy processes underlying their development and implementation. Indeed, the umbrella concept of soda taxation actually covers a diversity of objectives and mechanisms, which may not only condition the feasibility and acceptability of a proposal, but also alter its impact. We briefly highlight some conditions that may have influenced soda tax policy processes and why further theory-driven case studies may be instructive

Polysaccharide Blend Fibres Formed from NaOH, N-Methylmorpholine-N-oxide and 1-Ethyl-3-methylimidazolium acetate

Article disponible sur le site de l'éditeur : http://www.fibtex.lodz.pl/article330.htmlInternational audienceThe aim of the study was to find new structured biopolymer blends bearing adjustable properties able to produce innovative materials. Apart from cellulose and three solvents (NaOH, N-methylmorpholine-N-oxide [NMMO] and 1-ethyl-3-methylimidazolium acetate [EMIMac]), 15 different polysaccharides were chosen to study the interactions ofpolysaccharides or their mixtures in solutions, as well as the solid state after forming. Dissolution screenings yielded promising polysaccharides, which were used for the preparation of cellulose/ polysaccharide solutions and subsequently for the shaping of blends with cellulose. The solubility and miscibility were evaluated by microscopy, DSC, particle analysis and rheology. Polysaccharides with a structure similar to that of cellulose, e.g., xylan, carrageenan or cellulose carbamate were not miscible, showing globular morphologies, whereas high-molar and side chains containing polysaccharides such as xanthan or tragacanth gum form co-continuous morphologies. The forming of blend fibres was nevertheless possible for all three solvents. The textile-physical properties of the blend fibres were slightly decreased compared to those of the unmodified fibre, in which fibres from NMMO and EMIMac had the highest performance. The presence of blended polysaccharides in the fibres produced was verified by residue sugar analysis, in which the highest amounts occurred for EMIMac fibres

The Evolution of Field Early-Type Galaxies in the FDF and WHDF

We explore the properties of 24 field early-type galaxies at 0.20<z<0.75 down to M_B<=-19.30 in a sample extracted from the FORS Deep Field and the William Herschel Deep Field. High S/N intermediate-resolution VLT spectroscopy was complemented by deep high-resolution HST/ACS imaging and additional ground-based multi-band photometry. To clarify the low level of star formation (SF) detected in some galaxies, we identify the amount of AGN activity in our sample using archive data of Chandra and XMM-Newton X-ray surveys. The B and K-band Faber-Jackson relations and the Fundamental Plane display a moderate evolution for the field early-type galaxies. Lenticular (S0) galaxies feature on average a stronger luminosity evolution and bluer rest-frame colours which can be explained that they comprise more diverse stellar populations compared to elliptical galaxies. The evolution of the FP can be interpreted as an average change in the dynamical mass-to-light ratio of our galaxies as <\Delta \log{(M/L_B)}/z>=-0.74\pm0.08. The M/L evolution of these field galaxies suggests a continuous mass assembly of field early-type galaxies during the last 5 Gyr, that gets support by recent studies of field galaxies up to z~1. Independent evidence for recent SF activity is provided by spectroscopic (OII em., Hdelta) and photometric (rest-frame colors) diagnostics. Based on the Hdelta absorption feature we detect a weak residual SF for galaxies that accounts for 5%-10% in the total stellar mass of these galaxies. The co-evolution in the luminosity and mass of our galaxies favours a downsizing formation process. We find some evidence that our galaxies experienced a period of SF quenching, possible triggered by AGN activity that is in good agreement with recent results on both observational and theoretical side. (abridged)Comment: 26 pages, 23 figures, accepted for publication in MNRA

Spectral reflectance properties of iridescent pierid butterfly wings

The wings of most pierid butterflies exhibit a main, pigmentary colouration: white, yellow or orange. The males of many species have in restricted areas of the wing upper sides a distinct structural colouration, which is created by stacks of lamellae in the ridges of the wing scales, resulting in iridescence. The amplitude of the reflectance is proportional to the number of lamellae in the ridge stacks. The angle-dependent peak wavelength of the observed iridescence is in agreement with classical multilayer theory. The iridescence is virtually always in the ultraviolet wavelength range, but some species have a blue-peaking iridescence. The spectral properties of the pigmentary and structural colourations are presumably tuned to the spectral sensitivities of the butterflies’ photoreceptors

Imprecise probabilistic estimation of design floods with epistemic uncertainties

This is the author accepted manuscript. The final version is available from the publisher via the DOI in this record.An imprecise probabilistic framework for design flood estimation is proposed on the basis of the Dempster-Shafer theory to handle different epistemic uncertainties from data, probability distribution functions and probability distribution parameters. These uncertainties are incorporated in cost-benefit analysis to generate the lower and upper bounds of the total cost for flood control, thus presenting improved information for decision making on design floods. Within the total cost bounds, a new robustness criterion is proposed to select a design flood that can tolerate higher levels of uncertainty. A variance decomposition approach is used to quantify individual and interactive impacts of the uncertainty sources on total cost. Results from three case studies, with 127-, 104- and 54-year flood data sets respectively, show that the imprecise probabilistic approach effectively combines aleatory and epistemic uncertainties from the various sources and provides upper and lower bounds of the total cost. Between the total cost and the robustness of design floods, a clear trade-off which is beyond the information that can be provided by the conventional minimum cost criterion is identified. The interactions among data, distributions and parameters have a much higher contribution than parameters to the estimate of the total cost. It is found that the contributions of the various uncertainty sources and their interactions vary with different flood magnitude, but remain roughly the same with different return periods. This study demonstrates that the proposed methodology can effectively incorporate epistemic uncertainties in cost-benefit analysis of design floods.This study was supported by the National Natural Science Foundation of China (Grant No. 51320105010 and 51279021). The first author gratefully acknowledges the financial support provided by the China Scholarship Council. The authors are deeply indebted to editors, Dr Francesco Serinaldi and another anonymous reviewer for their valuable time and constructive suggestions that greatly improved the quality of this paper. The data of Three Gorges were obtained from the China Three Gorges Corporation. The data of Biliu were obtained from the Biliu reservoir administration. The data of Harbin were obtained from the Harbin hydrology bureau. These data are available as in Supporting Information Data Set which includes Data Set S1, Data Set S2 and Data Set S3. Data Set S1 corresponds to Three Gorges; Data Set S2 corresponds to Biliu; Data Set S3 corresponds to Harbin

The role of multixenobiotic transporters in predatory marine molluscs as counter-defense mechanisms against dietary allelochemicals

Author Posting. © The Author(s), 2010. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology 152 (2010): 288-300, doi:10.1016/j.cbpc.2010.05.003.Multixenobiotic transporters have been extensively studied for their ability to modulate the disposition and toxicity of pharmacological agents, yet their influence in regulating the levels of dietary toxins within marine consumers has only recently been explored. This study presents functional and molecular evidence for multixenobiotic transporter-mediated efflux activity and expression in the generalist gastropod Cyphoma gibbosum, and the specialist nudibranch Tritonia hamnerorum, obligate predators of chemically defended gorgonian corals. Immunochemical analysis revealed that proteins with homology to permeability glycoprotein (P-gp) were highly expressed in T. hamnerorum whole animal homogenates and localized to the apical tips of the gut epithelium, a location consistent with a role in protection against ingested prey toxins. In vivo dye assays with specific inhibitors of efflux transporters demonstrated the activity of P-gp and multidrug resistance-associated protein (MRP) families of ABC transporters in T. hamnerorum. In addition, we identified eight partial cDNA sequences encoding two ABCB and two ABCC proteins from each molluscan species. Digestive gland transcripts of C. gibbosum MRP-1, which have homology to vertebrate glutathione-conjugate transporters, were constitutively expressed regardless of gorgonian diet. This constitutive expression may reflect the ubiquitous presence of high affinity substrates for C. gibbosum glutathione transferases in gorgonian tissues likely necessitating export by MRPs. Our results suggest that differences in multixenobiotic transporter expression patterns and activity in molluscan predators may stem from the divergent foraging strategies of each consumer.Financial support was provided by the Ocean Life Institute Tropical Research Initiative Grant (WHOI) to KEW and MEH; the Robert H. Cole Endowed Ocean Ventures Fund (WHOI) to KEW; the National Undersea Research Center – Program Development Proposal (CMRC-03PRMN0103A) to KEW; and the National Science Foundation (Graduate Research Fellowship to KEW and DEB-0919064 to EES)