Non-Intrusive model coupling: A flexible way to handle local geometric and mechanical details in FEA

Computer Aided Engineering (CAE) often involves structural mechanics analysis (most of the time using the finite element method). When dealing with nonlinear complex models on large 3D structures, the computational cost becomes prohibitive. In this paper, we present the recent developments linked to an innovative computing method: non-intrusive coupling. Such a method allows to efficiently taking into account local modifications on an initial existing model in a non-intrusive way: the previously computed analysis is left unchanged. Large scale linear models can thus be easily computed, then localised nonlinear complex models can be used to pinpoint the analysis where required on the structure. After a presentation of the scientific context and a description of non-intrusive coupling methods, we will present its application to crack growth simulation and parallel structure analysis

Local/global non-intrusive parallel coupling for large scale mechanical analysis

The permanent increase in available computing resources can achieve more and more ambitious numerical simulations (most of the time using the finite element method). When dealing with non-linear complex models on large 3D structures, the computational cost becomes prohibitive. In this paper, we present the recent developments linked to an innovative computing method: non-intrusive coupling. Such a method allows to efficiently take into account local modifiations on an initial existing model in a non-intrusive way: the previously computed analysis is left unchanged. Large scale linear models can thus be easily computed, then localised non-linear complex models can be used to pinpoint the analysis where required on the structure. After a presentation of the scientific context and a description of non-intrusive coupling methods, we will present its application to crack growth simulation and parallel structure analysis

Ruminal methane inhibition potential of various pure compounds in comparison with garlic oil as determined with a rumen simulation technique (Rusitec)

Ruminants represent an important source of methane (CH4) emissions; therefore, CH4 mitigation by diet supplementation is a major goal in the current ruminant research. The objective of the present study was to use a rumen simulation technique to evaluate the CH4-mitigating potential of pure compounds in comparison with that achieved with garlic oil, a known anti-methanogenic supplement. A basal diet (15g DM/d) consisting of ryegrass hay, barley and soyabean meal (1:0·7:0·3) was incubated with the following additives: none (negative control); garlic oil (300mg/l incubation liquid; positive control); allyl isothiocyanate (75mg/l); lovastatin (150mg/l); chenodeoxycholic acid (150mg/l); 3-azido-propionic acid ethyl ester (APEE, 150mg/l); levulinic acid (300mg/l); 4-[(pyridin-2-ylmethyl)-amino]-benzoic acid (PABA, 300mg/l). Fermentation profiles (SCFA, microbial counts and N turnover) and H2 and CH4 formation were determined. Garlic oil, allyl isothiocyanate, lovastatin and the synthetic compound APEE decreased the absolute daily CH4 formation by 91, 59, 42 and 98%, respectively. The corresponding declines in CH4 emitted per mmol of SCFA were 87, 32, 40 and 99%, respectively, compared with the negative control; the total SCFA concentration was unaffected. Garlic oil decreased protozoal numbers and increased bacterial counts, while chenodeoxycholic acid completely defaunated the incubation liquid. In vitro, neutral-detergent fibre disappearance was lower following chenodeoxycholic acid and PABA treatments (−26 and −18%, respectively). In conclusion, garlic oil and APEE were extremely efficient at mitigating CH4 without noticeably impairing microbial nutrient fermentation. Other promising substances were allyl isothiocyanate and lovastati

AUTOMATIC BLOB FITTING IN COMPREHENSIVE TWO-DIMENSIONAL GAS CHROMATOGRAPHY IMAGES

Two-dimensional gas chromatography is a recent technology which is particularly efficient for detailed molecular analysis. However, due to the novelty of the method and the lack of automated analysis tools, quantitative data processing is often performed manually. Hence, results are strongly user-dependent, time consuming and, consequently, relatively inaccurate In this paper, we extend conventional techniques for signal analysis by utilizing specific characteristics of chromatographic data and by developing new methods for estimating the quantitative contribution of chemical regions from the produced images. Data-driven information is retrieved from chemical quantitative analysis based on Savitzky-Golay automatic peaks location determination, which increases both the processing speed and the analysis efficiency and improves our confidence in experimental repeatability. 1

Evaluation of antibacterial properties of essential oils and/or of their major components

La recherche de nouveaux traitements contre les maladies infectieuses est un sujet de pleine actualité : l’émergence et la dissémination des mécanismes de résistance aux antibactériens, l’importance croissante des infections associées aux soins, combinées à la quasi absence de nouveaux antibiotiques génèrent, au-delà de la santé individuelle, un véritable problème de santé publique. Il y a urgence à trouver et à proposer des nouvelles approches thérapeutiques pour le traitement de ces infections. Dans ce contexte, les Huiles Essentielles (HE) connues et utilisées depuis des siècles pour leurs propriétés anti-infectieuses, peuvent se révéler être une alternative au « tout antibiotique ». En effet, depuis plusieurs années, les HE connaissent un très net regain d’intérêt, et plusieurs études tendent à démontrer leurs réelles propriétés antimicrobiennes. Cependant, avant d’envisager toute utilisation des HE en thérapeutique anti-infectieuse, nous devons relever un défi de taille : à l’heure actuelle, aucun protocole expérimental, permettant d’évaluer in vitro les propriétés antibactériennes d’une HE, n’est validé ou recommandé par aucune autorité règlementaire, quelle qu’elle soit (Pharmacopée, ISO, ANSM…). L’objectif de cette revue est de présenter les différentes techniques utilisées ou utilisables pour l’évaluation in vitro des propriétés antibactériennes d’une HE, en soulignant les avantages et les inconvénients de chacune.The search for new treatments against infectious diseases is currently highlighted : the emergence and dissemination of resistance mechanisms to antibacterial drugs, the increasing importance of infections associated to healthcare, combined with the quasi inexistence of new antibiotics generates, beyond individual health, a real problem of public health. It is now urgent to find and to propose new therapeutic approaches for the treatment of these infections. In this context, essential oils (EO) known and used for centuries for their anti-infectious properties, may present as an alternative to “all-antibiotic”. As a matter of fact, since many years now E O aroused considerable new interest and many studies tend to support their real antimicrobial properties. However, before envisaging the use of EO in infectious therapeutics, we must face a considerable challenge: currently no experimental protocol allowing and in vitro evaluation of the antibacterial properties of an EO has been validated or recommended by any health authority whatsoever. The aim of this review is to present the different techniques used or which could be used for the in vitro evaluation of antibacterial properties of EO, underlining the advantages and drawbacks of each

GASP: from Modular Programming to Distributed Execution

International audienceWe present in this paper a generic animation and simulation platform which integrates the different animation models: descriptive, generative and behavioural models. The integration of these models in the same platform allows to offer to each dynamic entity a more realistic and a richer environment, and thereby to increase possible interactions between an actor and its environment. Therefore we describe the kernel of the platform, then we explain how it is used from the programmer point of view and we illustrate its use in the field of driving simulation

Control of the Evolution of Iron Peroxide Intermediate in Superoxide Reductase from Desulfoarculus baarsii. Involvement of Lysine 48 in Protonation

International audienceSuperoxide reductase is a nonheme iron metalloenzyme that detoxifies superoxide anion radicals O(2)(•-) in some microorganisms. Its catalytic mechanism was previously proposed to involve a single ferric iron (hydro)peroxo intermediate, which is protonated to form the reaction product H(2)O(2). Here, we show by pulse radiolysis that the mutation of the well-conserved lysine 48 into isoleucine in the SOR from Desulfoarculus baarsii dramatically affects its reaction with O(2)(•-). Although the first reaction intermediate and its decay are not affected by the mutation, H(2)O(2) is no longer the reaction product. In addition, in contrast to the wild-type SOR, the lysine mutant catalyzes a two-electron oxidation of an olefin into epoxide in the presence of H(2)O(2), suggesting the formation of iron-oxo intermediate species in this mutant. In agreement with the recent X-ray structures of the peroxide intermediates trapped in a SOR crystal, these data support the involvement of lysine 48 in the specific protonation of the proximal oxygen of the peroxide intermediate to generate H(2)O(2), thus avoiding formation of iron-oxo species, as is observed in cytochrome P450. In addition, we proposed that the first reaction intermediate observed by pulse radiolysis is a ferrous-iron superoxo species, in agreement with TD-DFT calculations of the absorption spectrum of this intermediate. A new reaction scheme for the catalytical mechanism of SOR with O(2)(•-) is presented in which ferrous iron-superoxo and ferric hydroperoxide species are reaction intermediates, and the lysine 48 plays a key role in the control of the evolution of iron peroxide intermediate to form H(2)O(2)

Non-intrusive Coupling: Recent Advances and Scalable Nonlinear Domain Decomposition

This paper provides a detailed review of the global/local non-intrusive coupling algorithm. Such method allows to alter a global finite element model, without actually modifying its corresponding numerical operator. We also look into improvements of the initial algorithm (Quasi- Newton and dynamic relaxation), and provide comparisons based on several relevant test cases. Innovative examples and advanced applications of the non-intrusive coupling algorithm are provided, granting a handy framework for both researchers and engineers willing to make use of such process. Finally, a novel nonlinear domain decomposition method is derived from the global/local non-intrusive cou- pling strategy, without the need to use a parallel code or software. Such method being intended to large scale analysis, we show its scalability. Jointly, an efficient high level Message Passing Interface coupling framework is also proposed, granting an universal and flexible way for easy software coupling. A sample code is also given

Indole 3-acetic acid, indoxyl sulfate and paracresyl-sulfate do not influence anemia parameters in hemodialysis patients

International audienceBackground: The main reason for anemia in renal failure patients is the insufficient erythropoietin production by the kidneys. Beside erythropoietin deficiency, in vitro studies have incriminated uremic toxins in the pathophysiology of anemia but clinical data are sparse. In order to assess if indole 3-acetic acid (IAA), indoxyl sulfate (IS), and paracresyl sulfate (PCS)-three protein bound uremic toxins-are clinically implicated in end-stage renal disease anemia we studied the correlation between IAA, IS and PCS plasmatic concentrations with hemoglobin and Erythropoietin Stimulating Agents (ESA) use in hemodialysis patients. Methods: Between June and July 2014, we conducted an observational cross sectional study in two hemodialysis center. Three statistical approaches were conducted. First, we compared patients treated with ESA and those not treated. Second, we performed linear regression models between IAA, IS, and PCS plasma concentrations and hemoglobin, the ESA dose over hemoglobin ratio (ESA/Hemoglobin) or the ESA resistance index (ERI). Third, we used a polytomous logistic regression model to compare groups of patients with no/low/high ESA dose and low/high hemoglobin statuses

Improving the antiprotozoal effect of saponins in the rumen by combination with glycosidase inhibiting inimosugars or by modification of their chemical structure

The antiprotozoal effect of saponins is transitory, as when saponins are deglycosylated to sapogenins by rumen microorganisms they become inactive. We hypothesised that the combination of saponins with glycosidase-inhibiting iminosugars might potentially increase the effectiveness of saponins over time by preventing their deglycosylation in the rumen. Alternatively, modifying the structure of the saponins by substituting the sugar moiety with other small polar residues might maintain their activity as the sugar substitute would not be enzymatically cleaved. The aim of this in vitro study was to evaluate the acute antiprotozoal effect and the stability of this effect over a 24 h incubation period using ivy saponins, a stevia extract rich in iminosugars, ivy saponins with stevia extract, and a chemically modified ivy saponin, hederagenin bis-succinate (HBS). The effects on fermentation parameters and rumen bacterial communities were also studied. Ivy saponins with stevia and HBS had a greater antiprotozoal effect than ivy saponins, and this effect was maintained after 24 h of incubation (P<0.001). The combination of ivy and stevia extracts was more effective in shifting the fermentation pattern towards higher propionate (+39%) and lower butyrate (-32%) and lower ammonia concentration (-64%) than the extracts incubated separately. HBS caused a decrease in butyrate (-45%) and an increase in propionate (+43%) molar proportions. However, the decrease in ammonia concentration (-42%) observed in the presence of HBS was less than that caused by ivy saponins, either alone or with stevia. Whereas HBS and stevia impacted on bacterial population in terms of community structure, only HBS had an effect in terms of biodiversity (P<0.05). It was concluded that ivy saponins with stevia and the modified saponin HBS had a strong antiprotozoal effect, although they differed in their effects on fermentation parameters and bacteria communities. Ivy saponins combined with an iminosugar-rich stevia extract and/or HBS should be evaluated to determine their antiprotozoal effect in vivopublishersversionPeer reviewe