Polyphenol, polysaccharide and lactate extraction from pulping factory black liquor by ionic liquids

International audienceExtraction of polyphenols, polysaccharides and organic acids present in a liquor issued from a pulping factory, so-called black liquor, was studied using two ionic liquids trihexyltetradecylphosphonium chloride ([P 66614 ]Cl) and trihexyltetradecylphosphonium bromide ([P 66614 ]Br). The extraction of each of the three compounds mentioned above was reported as a function of the dilution of the initial black liquor, the volume ratio of liquor vs. ionic liquid, and the initial pH of the black liquor. Polyphenols and polysaccharides were quantitatively extracted at room temperature with both ionic liquids. Extraction of lactate anions was found to be low, exhibiting distribution coefficients below 8 in all cases

ITyPA, un premier MOOC francophone et connectiviste

International audienceITyPA, première expérience francophone de MOOC (Massive Open Online Course) au travers d'un cours portant sur l'apprendre avec Internet, a permis de prouver la faisabilité d'une telle approche et de développer une nouvelle communauté de pratique autour de cette thématique. Cet article présente un premier bilan, et les caractéristiques principales de ce dispositif

Le numérique : une bibliothèque universelle pour la création scientifique ?

La réflexion qui suit trouve sa source dans l’expérience personnelle des auteurs et dans la pratique de leurs collègues français. Elle est propre aux sciences « exactes », mais certains constats, évolutions ou perspectives concernent certainement aussi d’autres secteurs disciplinaires. L’objet de ce propos est d’identifier le rôle et l’emploi de la documentation dans le processus d’élaboration cognitif qui mène le chercheur à la découverte, puis de cerner l’usage de la numérisation qui s’impo..

Un MOOC et ses partenaires - Remettre l'humain dans le massif

International audienceCes derniers mois, les MOOC ont attiré l'attention des professionnels de l'enseignement et la formation. Alors que la croissance des MOOC est phénoménale, des nombreuses critiques surgissent à propos des modèles économiques, l'ingénierie pédagogique insuffisante ou les taux d'abandon élevés. Du 10 octobre au 12 décembre 2013, la deuxième saison d'ITyPA a réuni quelques 2.600 participants. En collaboration avec une quarantaine de partenaires français et internationaux, des rencontres physiques et virtuelles étaient proposées afin de permettre aux inscrits de mieux appréhender les différents aspects du cours, de rythmer leur participation et de maintenir leur niveau de motivation. Du simple meet-up au programme de formation parallèle, les partenaires ont permis une plus grande personnalisation de l'expérience de l'apprenant dans le MOOC, un renforcement de l'ingénierie pédagogique et l'émergence de nouveaux modèles économiques

Medical Image Content-Based Queries using the Grid

International audienceComputation and data grids have encountered a large success among the scientific computing community in the past few years. The medical imaging community is increasingly aware of the potential benefit of these technologies in facing today medical image analysis challenges. In this paper, we report on a first experiment in deploying a medical application on a large scale grid testbed. Our pilot application is a hybrid metadata and image content-based query system that manipulates a large data set and for which image analysis computation can be easily parallelized on several grid nodes. We analyze the performances of this algorithm and the benefit brought by the grid. We further discuss possible improvements and future trends in porting medical applications to grid infrastructures

Severe portal and systemic acidosis during CO2-laparoscopy compared to helium or gasless laparoscopy and laparotomy in a rodent model: an experimental study

Background and aims: This experimental study assesses the influence of different gases and insufflation pressures on the portal, central-venous and peripheral-arterial pH during experimental laparoscopy. Methods: Firstly, 36 male WAG/Rij rats were randomized into six groups (n = 6) spontaneously breathing during anaesthesia: laparoscopy using carbon dioxide or helium at 6 and 12 mmHg, gasless laparoscopy and laparotomy. 45 and 90 min after setup, blood was sampled from the portal vein, vena cava and the common femoral artery with immediate blood gas analysis. Secondly, 12 animals were mechanically ventilated at physiological arterial pH during 90 min of laparotomy (n = 6) or carbon dioxide laparoscopy at 12 mmHg (n = 6) with respective blood gas analyses. Results: Over time, in spontaneously breathing rats, carbon dioxide laparoscopy caused significant insufflation pressure-dependent portal acidosis (pH at 6 mmHg, 6.99 [6.95-7.04] at 45 min and 6.95 [6.94-6.96] at 90 min, pH at 12 mmHg, 6.89 [6.82-6.90] at 45 min and 6.84 [6.81-6.87] at 90 min; p 0.05). Central-venous and peripheral-arterial acidosis was significant but less severely reduced during carbon dioxide laparoscopy. Laparotomy, helium laparoscopy and gasless laparoscopy showed no comparable acidosis in all vessels. Portal and central-venous acidosis during carbon dioxide laparoscopy at 12 mmHg was not reversible by mechanical hyperventilation maintaining a physiological arterial pH (pH portal 6.85 [6.84-6.90] (p = 0.004), central-venous 6.93 [6.90-6.99] (p = 0.004), peripheral-arterial 7.29 [7.29-7.31] (p = 0.220) at 90 min; Wilcoxon-Mann-Whitney test). Conclusion: Carbon dioxide laparoscopy led to insufflation pressure-dependent severe portal and less severe central-venous acidosis not reversible by mechanical hyperventilation. Keywords: Acidosis; Blood gases; Insufflation gas; Insufflation pressure; Laparoscop

Etude numérique d'écoulements du sang dans des domaines axisymétriques en présence d'une sténose importante avec un modèle de fluide à seuil

Nous présentons une contribution numérique à l'étude de l'écoulement du sang, considéré comme un fluide non-newtonien à seuil de contrainte, dans une artère sténosée. L'écoulement est supposé axisymétrique, laminaire, et la conduite comporte une sténose. Les effets de seuil sont pris en compte dans les simulations. A partir de données expérimentales de la littérature, le fluide est représenté par le modèle de Herschel-Bulkley, régularisé pour considérer le comportement aux faibles gradients de vitesse. Les résultats mettent en évidence l'influence du seuil sur les caractéristiques d'écoulement et l'apparition des zones rigides, en fonction des nombres de Reynolds et d'Oldroyd

Monographs on drugs which are frequently analyzed in therapeutic drug monitoring

In addition to the monographs which have been published in the past 4 years by the working group "Drug Monitoring” of the Swiss Society of Clinical Chemistry (SSCC) [1-4], new monographs have been written. The data presented in these monographs provide an overview of important information for the request and interpretation of results. Therefore, laboratory health professionals and the receivers of the reports are the targeted readers. In this series, several antiepileptic drugs are presented. Monographs on carbamazepine [1], lamotrigine [2], phenobarbital [2], and valproic acid [2] have been published previously. First, information about pharmacology and pharmacokinetics of these drugs (protein binding, metabolic pathways and enzymes involved, elimination half-life time and elimination route(s) of the parent drug and therapeutic as well as toxic concentrations) is given. Second, the indications for therapeutic drug monitoring are listed. Last but not least, important pre-analytical information is provided, including time points of blood sampling and time interval after which steady-state concentrations are reached after changing the dose. Furthermore, the stability of the drug and its metabolite(s) after blood sampling is described. For readers with a specific interest, references to important publications are given. The number of the monographs will be further enlarged. The updated files are presented on the homepage of the SSCC (www.sscc.ch). We hope that these monographs are helpful for the better handling of therapeutic drug monitoring and we are looking forward to comments from the reader

Oxidative Transformation of Dihydroflavonols and Flavan-3-ols by Anthocyanidin Synthase from Vitis vinifera

Twelve polyphenols from three distinct families (dihydroflavonols, flavan-3-ols, and flavanones) were studied as potential substrates of anthocyanidin synthase from Vitis vinifera (VvANS). Only flavan-3-ols of (2R,3S) configuration having either a catechol or gallol group on ring B are accepted as substrates. Only dihydroflavonols of (2R,3R) configuration are accepted as substrates, but a catechol or gallol group is not mandatory. Flavanones are not substrates of VvANS. HPLC and MS/MS analyses of the enzymatic products showed that the VvANS-catalyzed oxidative transformation of (+)-dihydroflavonols, such as dihydroquercetin, dihydrokaempferol and dihydromyricetin, leads only to the corresponding flavonols. Among the flavan-3-ols recognized as substrates, (+)-gallocatechin was only transformed into delphinidin by VvANS, whereas (+)-catechin was transformed into three products, including two major products that were an ascorbate–cyanidin adduct and a dimer of oxidized catechin, and a minor product that was cyanidin. Data from real-time MS monitoring of the enzymatic transformation of (+)-catechin suggest that its products are all derived from the initial C3-hydroxylation intermediate, i.e., a 3,3-gem-diol, and their most likely formation mechanism is discussed