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2018, Publications.


  • Azzi J, Auezova L, Danjou P-E, Fourmentin S, Greige-Gerges H. First evaluation of drug-in-cyclodextrin-in-liposomes as an encapsulating system for nerolidol. Food Chemistry 2018; 255: 399-404.
    Résumé : Nerolidol, a naturally occurring sesquiterpene with antimicrobial activities, is a promising candidate as a natural alternative for synthetic preservatives in food. However, its application is limited by low aqueous solubility and stability. In this study, conventional liposomes and drug-in-cyclodextrin-in-liposomes (DCLs) were evaluated for the first time as encapsulating materials for nerolidol. The size, encapsulation efficiency (EE%), loading rate (LR%), photo- and storage stabilities of both systems were characterized. Moreover, the in vitro release of nerolidol from liposomes and DCLs was investigated over time. Nerolidol was efficiently entrapped in both carriers with high EE% and LR% values. In addition, DCLs prolonged the release of nerolidol over one week and enhanced the photostability more effectively than conventional liposomes. Finally, all formulations were stable after 12 months of storage at 4 °C (>60% incorporated nerolidol). Therefore, DCLs are promising carriers for new applications of sesquiterpenes in the pharmaceutical and food industries.
    Mots-clés : Drug-in-cyclodextrin-in-liposomes, Liposomes, Nerolidol, Photostability, Release.

  • Azzi J, Jraij A, Auezova L, Fourmentin S, Greige-Gerges H. Novel findings for quercetin encapsulation and preservation with cyclodextrins, liposomes, and drug-in-cyclodextrin-in-liposomes. Food Hydrocolloids 2018; 81: 328-340.
    Résumé : The low solubility, poor bioavailability, and low chemical stability of quercetin (Quer) are the main drawbacks that limit its use as a food nutraceutical. In this study, the encapsulation in cyclodextrins (CDs), conventional liposomes (CLs), and drug-in-cyclodextrin-in-liposomes (DCLs) was conducted in order to improve the physicochemical properties of Quer. Phase solubility studies revealed an enhancement of Quer solubility upon complexation with various CDs. CLs composed of three different types of phospholipids (unsaturated egg Lipoid E80, unsaturated soybean Lipoid S100, and saturated soybean Phospholipon 90H) as well as DCLs were prepared by ethanol injection method and characterized. Liposomes constituted of Lipoid E80 showed small diameter, narrow size distribution, and higher encapsulation efficiency of Quer compared to the two other CLs. The photostability of Quer-loaded liposomes was also evaluated. Results show that Lipoid E80-liposomes allow a better protection of Quer against UV irradiation than those prepared using other lipids. This effect could be explained by their different membrane rigidity as determined by Atomic Force Microscopy (AFM). Moreover, the photostability of Quer was additionally improved when encapsulated in DCLs (SBE-β-CD/Quer inclusion complex in Lipoid E80 liposomes), in comparison to CLs. The same trend was obtained regarding the Quer stability in simulated gastrointestinal fluids. Finally, all liposome formulations were physically stable after 1 year of storage at 4 °C.
    Mots-clés : Cyclodextrin, Drug-in-cyclodextrin-in-liposomes, Liposomes, Quercetin, Stability.

  • Belakroum R, Gherfi A, Kadja M, et al. Design and properties of a new sustainable construction material based on date palm fibers and lime. Construction and Building Materials 2018; 184: 330-343.
    Résumé : Every year, huge quantities of date palm fibers (DPF) are produced and wasted all over the world. Using this natural fiber as raw material would contribute to the valorization of natural sustainable resources. This paper presents an experimental investigation of a new eco-material based on date palm fiber and lime. The experiments on the elaborated material investigate some mechanical, thermal, acoustic properties and moisture buffering capacity. The influence of the fiber/lime ratio on the behavior of the lightweight aggregate was studied systematically. The results of compressive strength testing indicated that PDF incorporation led to a reduction in resistance limit, however, the recorded average values are still acceptable. Also, it was observed that the thermal conductivity is sensitive to the variation of the fiber/lime composition ratio. The measured thermal conductivity reached a minimum of 0.091 W/m.K for samples of 50% fiber, which indicates that it can be used as a good thermal insulator. With regard to the sound absorption, the new material reveals good absorption capacity based on the measured sound absorption coefficient which is for 50% of fiber: for medium and high frequencies 0.65 and 0.55 respectively. Due to its porous morphology, the proposed material has the ability to absorb water vapor in a high relative humidity environment and to restore it in a dry one. Hence, it could therefore act as a hygric regulator. Measurements of moisture buffer value revealed that the material is classified as good or excellent depending on the percentage of fiber.
    Mots-clés : Acoustic absorption, Date palm fiber, Hygric regulator, Mechanical testing, Thermal properties.

  • Billet S, Landkocz Y, Martin PJ, et al. Chemical characterization of fine and ultrafine PM, direct and indirect genotoxicity of PM and their organic extracts on pulmonary cells. Journal of Environmental Sciences (China) 2018; 71: 168-178.
    Résumé : Particulate matter in ambient air constitutes a complex mixture of fine and ultrafine particles composed of various chemical compounds including metals, ions, and organics. A multidisciplinary approach was developed by studying physico-chemical characteristics and mechanisms involved in the toxicity of particulate atmospheric pollution. PM0.3-2.5 and PM2.5 including ultrafine particles were sampled in Dunkerque, a French industrialized seaside city. PM samples were characterized from a chemical and toxicological point of view. Physico-chemical characterization evidenced that PM2.5 comes from several sources: natural ones, such as soil resuspension and marine sea-salt emissions, as well as anthropogenic ones, such as shipping traffic, road traffic, and industrial activities. Human BEAS-2B lung cells were exposed to PM0.3-2.5, or to the Extractable Organic Matter (EOM) of PM0.3-2.5 and PM2.5. These exposures induced several mechanisms of action implied in the genotoxicity, such as oxidative DNA adducts and DNA Damage Response. The toxicity of PM-EOM was higher for the sample including the ultrafine fraction (PM2.5) containing also higher concentrations of polycyclic aromatic hydrocarbons. These results evidenced the major role of organic compounds in the toxicity of PM.
    Mots-clés : Air pollution particulate matter, Biotransformation, Genotoxicity, Physico-chemical characterization, PM(2.5), Ultrafine particles.

  • Bouzarour A, Pozzobon V, Perré P, Salvador S. Experimental study of torrefied wood fixed bed: Thermal analysis and source term identification. Fuel 2018; 234: 247-255.
    Résumé : In this paper, self-heating scenarii were experimented on torrefied wood chips under atmospheres containing oxygen. These tests were carried out in a packed bed reactor. The experimental device was equipped with numerous thermocouples at different levels in the wood bed reactor ensuring temperature monitoring. The impact of oxygen supply was investigated at low-temperature (150 °C) both regarding oxygen content and atmosphere gas flow rate. The related results pointed out the propensity of the wood bed to self-heating particularly under a growing oxygen content or a low flow rate of oxidizing gas causing thus a spontaneous combustion. Furthermore, during self-heating, the source term was assessed relying on the local energy balance equation based on the experimental temperature fields. To summarize all results, source term values were fitted to a basic heat generation term of an oxidation reaction expressed as follows: Π=ΔH×∊×Aexp-EaRT×ρO2n. The optimized parameter values are: Ea = 99.8 kJ/mol, A = 2.50 × 109 s−1kgm3(1-n), n = 0.734, ΔH=14.062MJ/kgO2.
    Mots-clés : Reactor scale, Self-heating, Self-ignition, Source term, Theoretical analysis, Torrefied wood.

  • Chastang T, Pozzobon V, Taidi B, Courot E, Clément C, Pareau D. Resveratrol production by grapevine cells in fed-batch bioreactor: Experiments and modelling. Biochemical Engineering Journal 2018; 131: 9-16.
    Résumé : The purpose of this work was to scale-up the culture of grapevine cells (Vitis labrusca) from shake-flasks (100 mL) to a 5L stirred bioreactor in order to develop a model able to describe the bioproduction of resveratrol under the controlled conditions of a fed-batch culture. For this study, the biomass, resveratrol and sugar concentrations as well as pH and dissolved oxygen were monitored daily. The experiments were conducted twice over a three month period. The culture was elicited during the exponential growth phase with methyl jasmonate, leading the cells to exhibit a complex behaviour during the resveratrol production phase. A model of the system behaviour involving simple mechanisms is proposed and successfully confronted to the experimental results. This model demonstrates that the system dynamic can be decomposed into four phases: a lag phase (cell growth slowing down), a starting phase (beginning of resveratrol production), a surge phase (significant resveratrol production accompanied by significant cell death) and a stationary phase. Thus, we were able to successfully scale-up resveratrol production from 100 mL flasks to 5L bioreactors.
    Mots-clés : Fed-batch culture, Modelling, Plant cell bioreactors, Resveratrol.

  • Costantine G, Maalouf C, Moussa T, Polidori G. Experimental and numerical investigations of thermal performance of a Hemp Lime external building insulation. Building and Environment 2018; 131: 140-153.
    Résumé : Hemp-concrete is a green material which has become nowadays highly recommended in the construction field. It finds applications as internal or external thermal insulator in wooden frame walls. At wall scale, studies proved that using Hemp-concrete in building envelope can improve indoor hygrothermal comfort. However, at building scale, hemp-concrete is scarcely studied. In that context, a French building in Grand-Est region, Champagne-Ardennes, employing hemp-concrete as external insulator is selected and studied. An apartment is monitored for several months. Indoor temperatures, relative humidities, thermal heat flux as well as external weather conditions are measured using sensors installed inside the apartment and a weather station at the building roof. Measurements underline the hemp-concrete ability to dampen external weather conditions by showing good results for both indoor temperature and relative humidity. Experimental approach is then coupled with a numerical validation at the wall and room scales using SPARK simulation tool. Investigations are conducted on thermal heat flux through the wall, indoor office air temperature, and relative humidity. Results show a good agreement between numerical values and experimental measurements.
    Mots-clés : Experimental measurements, Hemp-concrete, Monitoring, Numerical validation, SPARK.

  • Crini G, Fourmentin S, Fenyvesi É, Torri G, Fourmentin M, Morin-Crini N. Cyclodextrins, from molecules to applications. Environmental Chemistry Letters 2018. doi:10.1007/s10311-018-0763-2.
    Résumé : Cyclodextrins are among the most remarkable macrocyclic molecules with significant theoretical and practical impacts in chemistry and biology. Cyclodextrins belong to the family of cage molecules due to their structure, which is composed of a hydrophobic cavity that can encapsulate other molecules. Indeed, the most characteristic feature of these compounds is their ability to form inclusion complexes with various molecules through host–guest interactions. This is at the origin of many applications. It is well known and widely reported in the literature that cyclodextrins and their derivatives have a wide variety of practical applications including pharmacy, medicine, foods, cosmetics, toiletries, catalysis, chromatography, biotechnology, nanotechnology, and textile industry. Cyclodextrins are also the object of numerous fundamental studies. In this review, we chose to highlight selected works on cyclodextrins published over the last 5 years by different research groups. The main objective is to summarize some of the recent developments related to the applications of cyclodextrins.
    Mots-clés : Applications, Cyclodextrin, Recent overview.

  • Du H, Ayouz M, Lv P, Perré P. A lattice-based system for modeling fungal mycelial growth in complex environments. Physica A: Statistical Mechanics and its Applications 2018; 511: 191-206.
    Résumé : Fungi are one of the most destructive agents to wood and wood-based products, resulting in the decrease of the building service life by breaking down lumber structures. This work presents a discrete lattice-based model to simulate the mycelial growth, which explicitly incorporates tip extension, extension angle, branching and anastomosis. The developed algorithm reduces greatly the geometrical restriction of the lattice to hyphal elongation; thus, it is able to generate realistic mycelial networks with low computational costs. Different growth conditions are reproduced via tropisms which influence the tip dominant direction, such as thigmotropism that enables hyphae to bend around the obstacles in structurally-heterogeneous media. The validation of this model is implemented through an experiment focusing on the morphology and the growth of Postia placenta, a species of brown rot fungus. Some model parameters are directly obtained from the experimental data, while others have to be determined by inverse procedure. This validated model is an efficient tool for predicting the mycelial growth under different conditions over a large spatial scale, thereby allowing upscaling from laboratory to macroscopic scale.
    Mots-clés : Discrete modeling, Heterogeneous media, Lattice-based, Mycelial network.

  • Esmaeel Q, Miotto L, Rondeau M, et al. Paraburkholderia phytofirmans PsJN-Plants Interaction: From Perception to the Induced Mechanisms. Frontiers in Microbiology 2018; 9. doi:10.3389/fmicb.2018.02093.
    Résumé : The use of plant-associated bacteria has received many scientific and economic attention as an effective and alternative method to reduce the chemical pesticides use in agriculture. The genus Burkholderia includes at least 90 species including pathogenic strains, plant pathogens, as well as plant beneficial species as those related to Paraburkholderia, which has been reported to be associated with plants and exerts a positive effect on plant growth and fitness. Paraburkholderia phytofirmans PsJN, a beneficial endophyte able to colonize a wide range of plants, is an established model for plant-associated endophytic bacteria. Indeed, in addition to its plant growth promoting ability, it can also induce plant resistance against biotic as well as abiotic stresses. Here, we summarized an inventory of knowledge on PsJN-plant interaction, from the perception to the resistance mechanisms induced in the plant by a way of the atypical colonization mode of this endophyte. We also have carried out an extensive genome analysis to identify all gene clusters which contribute to the adaptive mechanisms under different environments and partly explaining the high ecological competence of P. phytofirmans PsJN.
    Mots-clés : Biotic and abiotic stress, endophyte, Paraburkholderia phytofirmans PsJN, Perception, PGPR.

  • Eyssautier-Chuine S, Calandra I, Vaillant-Gaveau N, et al. A new preventive coating for building stones mixing a water repellent and an eco-friendly biocide. Progress in Organic Coatings 2018; 120: 132-142.
    Résumé : The durability of stone monuments is a constant problem as their decay through weathering is irremediable and endless. Fortunately, coatings are becoming more and more efficient and tailored to specific alterations of the stone material. This study aimed at developing an eco-friendly coating with both hydrophobic and biocide properties based on a silane/siloxane emulsion as a water repellent combined with chitosan and silver nitrate as biocides. Chitosan was first added at different concentrations to the water repellent and its efficacy was tested in laboratory conditions by the inoculation of axenic suspension of the green algae Chlorella vulgaris on a building porous limestone. Chlorophyll a fluorescence analysis displayed the chitosan acted on the photosystem of algae and limited their development but its effect was not optimal and higher dose modified the aspect of the stone. Low concentration of silver nitrate achieved a good performance thanks to the combination with the chitosan and the water repellent. The properties of coated stones and the efficacy of the formulation were assessed at two different doses of coating. The results showed that the lowest dose gathered all requirements to both preserve the stone monument with a weak colour change over time and to reach optimal biocide effect and a good hydrophobicity.
    Mots-clés : Biocide, Chitosan, Coating, Cultural Heritage, Hydrophobic, Silane/siloxane.

  • Fattorini L, Hause B, Gutierrez L, et al. Jasmonate promotes auxin-induced adventitious rooting in dark-grown Arabidopsis thaliana seedlings and stem thin cell layers by a cross-talk with ethylene signalling and a modulation of xylogenesis. BMC plant biology 2018; 18: 182.
    Résumé : BACKGROUND: Adventitious roots (ARs) are often necessary for plant survival, and essential for successful micropropagation. In Arabidopsis thaliana dark-grown seedlings AR-formation occurs from the hypocotyl and is enhanced by application of indole-3-butyric acid (IBA) combined with kinetin (Kin). The same IBA + Kin-treatment induces AR-formation in thin cell layers (TCLs). Auxin is the main inducer of AR-formation and xylogenesis in numerous species and experimental systems. Xylogenesis is competitive to AR-formation in Arabidopsis hypocotyls and TCLs. Jasmonates (JAs) negatively affect AR-formation in de-etiolated Arabidopsis seedlings, but positively affect both AR-formation and xylogenesis in tobacco dark-grown IBA + Kin TCLs. In Arabidopsis the interplay between JAs and auxin in AR-formation vs xylogenesis needs investigation. In de-etiolated Arabidopsis seedlings, the Auxin Response Factors ARF6 and ARF8 positively regulate AR-formation and ARF17 negatively affects the process, but their role in xylogenesis is unknown. The cross-talk between auxin and ethylene (ET) is also important for AR-formation and xylogenesis, occurring through EIN3/EIL1 signalling pathway. EIN3/EIL1 is the direct link for JA and ET-signalling. The research investigated JA role on AR-formation and xylogenesis in Arabidopsis dark-grown seedlings and TCLs, and the relationship with ET and auxin. The JA-donor methyl-jasmonate (MeJA), and/or the ET precursor 1-aminocyclopropane-1-carboxylic acid were applied, and the response of mutants in JA-synthesis and -signalling, and ET-signalling investigated. Endogenous levels of auxin, JA and JA-related compounds, and ARF6, ARF8 and ARF17 expression were monitored. RESULTS: MeJA, at 0.01 μM, enhances AR-formation, when combined with IBA + Kin, and the response of the early-JA-biosynthesis mutant dde2-2 and the JA-signalling mutant coi1-16 confirmed this result. JA levels early change during TCL-culture, and JA/JA-Ile is immunolocalized in AR-tips and xylogenic cells. The high AR-response of the late JA-biosynthesis mutant opr3 suggests a positive action also of 12-oxophytodienoic acid on AR-formation. The crosstalk between JA and ET-signalling by EIN3/EIL1 is critical for AR-formation, and involves a competitive modulation of xylogenesis. Xylogenesis is enhanced by a MeJA concentration repressing AR-formation, and is positively related to ARF17 expression. CONCLUSIONS: The JA concentration-dependent role on AR-formation and xylogenesis, and the interaction with ET opens the way to applications in the micropropagation of recalcitrant species.
    Mots-clés : Adventitious rooting, ARF17, EIN3/EIL1, Ethylene, Jasmonate, Thin cell layers, Xylogenesis.

  • Gharib R, Fourmentin S, Charcosset C, Greige-Gerges H. Effect of hydroxypropyl-β–cyclodextrin on lipid membrane fluidity, stability and freeze-drying of liposomes. Journal of Drug Delivery Science and Technology 2018; 44: 101-107.
    Résumé : Although liposomes loaded with drug-cyclodextrin complexes have been proposed as drug delivery systems, the effects of cyclodextrins on the stability and fluidity of lipid membranes is still poorly understood. In this study, liposomes were prepared with the thin film hydration method and the effects of hydroxypropyl-β-cyclodextrin (HP-β-CD) on dipalmitoyl phosphatidyl choline (DPPC) membranes were investigated for the first time by differential scanning calorimetry, Raman spectroscopy and DPH fluorescence anisotropy at various HP-β-CD to DPPC molar ratios. HP-β-CD interacted with the choline head group of the phospholipids and with the DPPC alkyl chains, leading to an increase in the chain disorder. HP-β-CD loaded liposomes were also prepared with the ethanol injection method, using saturated and unsaturated phospholipids in the presence of cholesterol. HP-β-CD increased the disorder of unsaturated phospholipid bilayers, while no increase was observed for saturated ones. Furthermore, HP-β-CD present in the aqueous phase of saturated phospholipid liposomes protected them during freeze-drying.
    Mots-clés : Freeze-drying, Hydroxypropyl-β-cyclodextrin, Liposomes, Phospholipids.

  • Gharib R, Greige-Gerges H, Fourmentin S, Charcosset C. Hydroxypropyl-ß-cyclodextrin as a membrane protectant during freeze-drying of hydrogenated and non-hydrogenated liposomes and molecule-in-cyclodextrin-in- liposomes: Application to trans-anethole. Food Chemistry 2018; 267: 67-74.
    Résumé : The effect of hydrogenation of phospholipids on the characteristics of freeze-dried liposomes was investigated using hydroxypropyl-ß-cyclodextrin (HP-ß-CD) as membrane protectant. The ethanol-injection method was applied to prepare liposomes using hydrogenated (Phospholopion-90H and 80H) and non-hydrogenated phospholipids (Lipoid-S100) in combination with cholesterol. Various liposomal formulations were tested: conventional liposomes (CL) and HP-ß-CD-loaded liposomes (CDL). Liposome suspensions were concentrated by ultracentrifugation; the pellets were reconstituted in water or CD solution and the dispersions were characterized for their size, polydispersity index and zeta potential. Results demonstrated that HP-ß-CD protected only the hydrogenated batches (CL and CDL) during freeze-drying. Moreover, the presence of HP-ß-CD in the aqueous phase of CDL protected them during freeze-drying. Freeze-dried CL and CDL made of phospholipon-90H loading anethole were demonstrated to be physically stable upon reconstitution in HP-ß-CD solutions, and are able to retain anethole after 6 months of storage at 4 °C thereby making them valuable for food applications.
    Mots-clés : -anethole, Conventional liposomes, Freeze-drying, Guest-in-cyclodextrin-in-liposome, Hydroxypropyl-ß-cyclodextrin, Phospholipon 90H, Release studies.

  • Habrylo O, Evangelista DE, Castilho PV, Pelloux J, Henrique-Silva F. The pectinases from Sphenophorus levis: Potential for biotechnological applications. International Journal of Biological Macromolecules 2018; 112: 499-508.
    Résumé : Pectinases represent about one fifth of the enzyme worldwide market due their wide range of biotechnological applications. Current commercial pectinases are exclusively obtained from microbial sources, but here we report a pectin methylesterase (Sl-PME) and an endo-polygalacturonase (Sl-EPG) bioprospected from the sugarcane weevil, Sphenophorus levis, which revealed good potential for industrial applications. Sl-PME and Sl-EPG were overexpressed in Pichia pastoris, purified and enzymatically characterized. Sl-EPG presents optimal activity at pH 4–5 and 50 °C, showing that it can be used for juice extraction and clarification. On the other hand, Sl-PME presents optimal activity at pH 6–8 and 40 °C, and thus, suitable for both acidic and alkaline processing, such as coffee and tea fermentation. Sl-EPG shows Vmax = 3.23 mM/min, KM = 2.4 g/L and kcat = 418.6 s−1. While Sl-PME shows Vmax = 0.14 mM/min, KM = 4.1 g/L and kcat = 1.7 s−1. A PG inhibitor (PGIP2) weakly interfered in the Sl-EPG activity and Sl-PME was not affected by a usual PME inhibitor. Moreover, these enzymes manifested synergistic action towards methylesterified pectin. Here, we propose these enzymes as novel alternative tools for the current commercial pectinases.
    Mots-clés : Pectin methylesterase, Pectinases, Polygalacturonase, Sugarcane weevil, Synergy.

  • Hatmi S, Villaume S, Trotel-Aziz P, Barka EA, Clément C, Aziz A. Osmotic Stress and ABA Affect Immune Response and Susceptibility of Grapevine Berries to Gray Mold by Priming Polyamine Accumulation. Frontiers in Plant Science 2018; 9. doi:10.3389/fpls.2018.01010.
    Résumé : Abiotic factors inducing osmotic stress can affect plant immunity and resistance against pathogen attack. Although a number of studies have characterized grapevine responses to various forms of biotic and abiotic stresses, the relationships between osmotic stress response and susceptibility of mature berries to Botrytis cinerea still remain unknown. In this study, we investigated the effects of osmotic stress and ABA on defense responses of mature grapevine berries before and after B. cinerea infection. We focused on the possible involvement of polyamines in the interaction between osmotic stress response and susceptibility to B. cinerea. We showed that osmotic stress induced by PEG or sucrose, and exogenous ABA induce transient but low defense responses, including weak expression of PR genes and phytoalexin synthesis in mature berries. This was accompanied by an upregulation of NCED2 involved in ABA biosynthesis and a large production of free polyamines. However, osmotic stress followed by B. cinerea infection primed berries for enhanced accumulation of polyamines, but slowed down the defense responses and increased susceptibility to the pathogen. A weak increase of diamine-and polyamine-oxidase activities was also recorded in stressed berries, but declined after pathogen infection. This suggests a possible connection between increased polyamine titer and weakened defense responses in infected berries. The pretreatment of stressed berries with appropriate inhibitors of diamine- and polyamine-oxidases further increased polyamine level and greatly lowered defense responses, leading to higher susceptibility to B. cinerea. These results are consistent with the hypothesis that low polyamine oxidation can contribute at least in part to lower defense responses by increasing polyamine titer, and subsequent disease susceptibility.
    Mots-clés : ABA, Botrytis cinerea, immune response, osmotic stress, phytoalexins, Polyamines, Vitis vinifera..

  • Hawila AA-W, Merabtine A, Chemkhi M, Bennacer R, Troussier N. An analysis of the impact of PMV-based thermal comfort control during heating period: A case study of highly glazed room. Journal of Building Engineering 2018; 20: 353-366.
    Résumé : Low energy consumption buildings are rapidly spreading over Europe. Its underlying concept is based on improving the building envelope, and using high efficiency equipment. However, thermal comfort in such buildings is still questionable. Recently, advanced comfort-based control strategies have been proposed in order to fulfill a tradeoff between energy-saving and occupants comfort as well as reduce additional investments compared to conventional energy reduction solutions. Though few studies focused on the European climate conditions during a heating period, this study aims at investigating the sensitivity of energy-saving potential to outdoor climatic conditions and identifying the significant parameters affecting the heating energy consumption in a comfort-controlled highly glazed room under a European climatic condition. A validated model is used to carry out a comparative building simulation study between PMV-based comfort-control and conventional thermostatic-control, as well as a sensitivity study based on the Design of Experiments technique. The results show that PMV-based comfort-control is a reasonable solution to neutralize the trade-off between thermal comfort and heating energy consumption under the investigated European winter season. Moreover, the results demonstrate that energy consumption using the comfort-control is more sensitive to outdoor climatic conditions than the thermostatic-control. Furthermore, the results show that energy consumption in a comfort-controlled space is highly sensitive to occupants-related parameters (metabolic rate and clothing level) and the mean radiant temperature compared to other parameters, such as relative humidity. Finally, a meta-model is obtained to be used as a fast and simple way to predict the energy consumption in a comfort-controlled room.
    Mots-clés : Design of experiment, Energy saving, Heating-energy consumption, PMV, Sensitivity analysis, Thermal comfort control.

  • Husson E, Auxenfans T, Herbaut M, et al. Sequential and simultaneous strategies for biorefining of wheat straw using room temperature ionic liquids, xylanases and cellulases. Bioresource Technology 2018; 251: 280-287.
    Résumé : Sequential and simultaneous strategies for fractioning wheat straw were developed in combining 1-ethyl-3-methyl imidazolium acetate [C2mim][OAc], endo-xylanases from Thermobacillus xylanilyticus and commercial cellulases. After [C2mim][OAc]-pretreatment, hydrolysis catalyzed by endo-xylanases of wheat straw led to efficient xylose production with very competitive yield (97.6 ± 1.3%). Subsequent enzymatic saccharification allowed achieving a total degradation of cellulosic fraction (>99%). These high performances revealed an interesting complementarity of [C2mim][OAc]- and xylanase-pretreatments for increasing enzymatic digestibility of cellulosic fraction in agreement with the structural and morphological changes of wheat straw induced by each of these pretreatment steps. In addition a higher tolerance of endo-xylanases from T. xylaniliticus to [C2mim][AcO] until 30% v/v than cellulases from T. reesei was observed. Based on this property, a simultaneous strategy combining [C2mim][OAc]- and endo-xylanases as pretreatment in a one-batch produced xylose with similar yield than those obtained by the sequential strategy.
    Mots-clés : Cellulase, Ionic liquid, Lignocellulosic biomass, Sequential and simultaneous process, Xylanase.

  • Ioannou I, M'hiri N, Chaaban H, Boudhrioua NM, Ghoul M. Effect of the process, temperature, light and oxygen on naringin extraction and the evolution of its antioxidant activity. International Journal of Food Science & Technology 2018. doi:10.1111/ijfs.13887.
    Résumé : Citrus co-products are rich in flavonones among them naringin. This compound exhibits several biological activities. These properties are mainly due to its antioxidant activity. The purpose of this work was in one hand to compare five technics of extraction conducted under different operating conditions and in the other hand, to analyse the effects of temperature, light and oxygen on naringin degradation and on the evolution of its antioxidant activity. The results obtained showed that the ultrasound assisted extraction leads to the highest naringin content and the thermal degradation of naringin occurs only for higher temperatures above 100 °C. Moreover, the naringin appears to be sensitive to an exposure to visible light (16.5 klux). The effect of the oxygen is less pronounced due to the lack of the enone structure and a hydroxyl group in position 3. The antioxidant activity of naringin is significantly affected by the light and high temperature.
    Mots-clés : Antioxidant activity, extraction method, flavonoids, naringin, optimisation, orange peel.

  • Karaky H, Maalouf C, Bliard C, et al. Hygrothermal and Acoustical Performance of Starch-Beet Pulp Composites for Building Thermal Insulation. Materials (Basel, Switzerland) 2018; 11. doi:10.3390/ma11091622.
    Résumé : This article deals with the elaboration and the characterization of an innovative 100% plant-based green composite made solely of beet pulp (BP) and potato starch (S). Using this type of material in insulation applications seems a good solution to reduce the CO₂ gas emissions in building. The influence of the starch amount on composite characteristics was studied. Four mixtures were considered with different S/BP mass ratios (0.1, 0.2, 0.3 and 0.4). The physical properties of these materials were studied in terms of porosity, apparent and absolute densities, thermal conductivity, and hygric properties. The influence of humidity content on acoustical properties was studied as a function of frequency. Test results show a real impact of both starch and humidity contents on the hygrothermal and acoustical properties of the studied material due to the porosity. The composite with the lowest amount of starch (S/BP = 0.1) seems to be the optimal composition in terms of the hygrothermal and acoustical behaviors.
    Mots-clés : acoustical performance, bio-based composite, hygrothermal performance, porosity, starch–beet pulp, thermal conductivity.

  • Kervroëdan L, Armand R, Saunier M, Ouvry J-F, Faucon M-P. Plant functional trait effects on runoff to design herbaceous hedges for soil erosion control. Ecological Engineering 2018; 118: 143-151.
    Résumé : Vegetation controls concentrated runoff and erosion in the European loess belt by increasing hydraulic roughness and sediment retention. Studies of plant effects on runoff velocity are usually based on a taxonomical characterisation and do not consider the effects of aboveground plant functional traits in attempts to understand soil erosion by water. This trait-based plant study investigates aboveground plant functional trait effects of herbaceous hedges on the hydraulic roughness to understand soil erosion. Eight aboveground morphological traits were measured on fourteen indigenous and perennial plant species (caespitose or comprising dry biomass in winter) from north-west Europe with a high morphological variability. For each trait, density-weighted traits were calculated. The effects of traits and density-weighted traits were examined using a runoff simulator with four discharges. The leaf density and area, as well as density-weighted stem and leaf areas, stem diameter and specific leaf area were positively correlated with the hydraulic roughness. Generalised linear models defined the best combinations of traits and density-weighted traits: (1) leaf density and leaf area, (2) density-weighted leaf area and density-weighted projected stem area, and (3) density-weighted leaf area and density-weighted stem diameter. Moreover, the effects of leaf density, leaf area and density-weighted specific leaf area, varied depending on the discharge. This study is one of the first characterisation of aboveground trait effects on hydraulic roughness and highlights that vegetation with large stem density, diameter and leaf area plays a significant role in minimising soil erosion. The selection of plant species can derive from these plant trait effects to design reconstructed herbaceous hedges to minimise soil erosion.
    Mots-clés : Aboveground functional traits, Ecohydrological processes, Hydraulic roughness, Plant-runoff interaction, Sediment retention, Soil erosion control.

  • Kfoury M, Landy D, Fourmentin S. Contribution of headspace to the analysis of cyclodextrin inclusion complexes. 2018. (consulté 7 sept.2018).
    Résumé : Headspace technology is a sampling method of a gas, which has been previously in contact with a liquid or a solid matrix from which volatiles were released into the gaseous phase. It is generally coupled to a subsequent gas chromatography analysis. The headspace analysis can be carried out either as a one-step extraction (static or equilibrium headspace) or as a continuous extraction (dynamic headspace). The static headspace gas chromatography (SH-GC) is gaining an increasing interest for the study of cyclodextrin (CD) inclusion complexes with volatile compounds. CDs are natural supermolecular hosts able to encapsulate volatile compounds and improve their functionalities (e.g. solubility, stability, retention, controlled release). Herein, the application of the SH-GC in the CD field will be reviewed. This paper will focus on the characterization of the inclusion complexes via the SH-GC, mainly aiming at the determination of formation constant (Kf) and encapsulation efficiency (EE%) values. Moreover, it will review the application of the SH-GC to monitor the properties of volatile compounds upon encapsulation (e.g. retention, controlled release).

  • Kfoury M, Landy D, Fourmentin S, Kfoury M, Landy D, Fourmentin S. Characterization of Cyclodextrin/Volatile Inclusion Complexes: A Review. Molecules 2018; 23: 1204.
    Résumé : Cyclodextrins (CDs) are a family of cyclic oligosaccharides that constitute one of the most widely used molecular hosts in supramolecular chemistry. Encapsulation in the hydrophobic cavity of CDs positively affects the physical and chemical characteristics of the guests upon the formation of inclusion complexes. Such a property is interestingly employed to retain volatile guests and reduce their volatility. Within this scope, the starting crucial point for a suitable and careful characterization of an inclusion complex is to assess the value of the formation constant (Kf), also called stability or binding constant. This task requires the application of the appropriate analytical method and technique. Thus, the aim of the present paper is to give a general overview of the main analytical tools used for the determination of Kf values for CD/volatile inclusion complexes. This review emphasizes on the advantages, inconvenients and limits of each applied method. A special attention is also dedicated to the improvement of the current methods and to the development of new techniques. Further, the applicability of each technique is illustrated by a summary of data obtained from the literature.
    Mots-clés : cyclodextrin, fluorescence, formation constant, HPLC, ITC, NMR, phase solubility, SH-GC, TOC, UV-Visible, volatiles.

  • Kfoury M, Auezova L, Greige-Gerges H, Fourmentin S. Encapsulation in cyclodextrins to widen the applications of essential oils. 2018. (consulté 7 sept.2018).
    Résumé : There is a growing interest for aromatic and biological properties of essential oils as alternatives to synthetic chemicals and drugs. However, essential oils and their components are poorly soluble in aqueous systems and are highly sensitive to degradation and evaporation. These drawbacks can be overcome by encapsulation into cyclodextrins, which are non-toxic cyclic oligosaccharides obtained from the enzymatic degradation of starch. Cyclodextrins inclusion complexes offer solutions to many limitations of the use of essential oils in the food, pharmaceutical and cosmetic industries. This article reviews essential oils encapsulation in cyclodextrins. The strength of binding between cyclodextrins and essential oils components covers a wide range of formation constants with values ranging from 13 to 166,338 M−1. The encapsulation in cyclodextrins can increase the aqueous solubility of essential oils up to 16-fold and reduce their photodegradation rates up to 44-fold, while ensuring a gradual release. We also discuss the effect of encapsulation on biological activities, such as antimicrobial and antioxidant properties of essential oils. Finally, we present novel cyclodextrin-based approaches in the sectors of textiles and nanofibres.

  • Landy D. Measuring Binding Constants of Cyclodextrin Inclusion Compounds. Cyclodextrin Fundamentals, Reactivity and Analysis 2018; : 223-255.
    Résumé : The affinity of cyclodextrins for organic and even inorganic pollutants has led to the development of numerous remediation methods at the laboratory scale. Indeed, the hydrophobic cavity of cyclodextrins constitute a versatile vehicle for the efficient transfer of various pollutants from their initial environmental compartment to the cyclodextrin cavity. This transfer can be applied to any environmental media such as soil, water or atmosphere, because cyclodextrins can be dissolved in water solutions or immobilized on solid supports. Both recovery or destructive processes have thus been designed on the basis of cyclodextrin affinity for the target pollutants. As a consequence, the stability of host-guest edifices is of crucial importance for the efficiency of cyclodextrin applications. Therefore, formation constants of such inclusion compounds have been thoroughly investigated, aiming at the custom design of host-guest couples for a given application. Indeed, the molecular shape of the cavity, and consequently the inclusion compound stability, can be tuned by using cyclodextrins of different size or by taking advantage of chemical modifications on the macrocycle.Nevertheless, the rational design of the perfect cyclodextrin may be hindered by a large uncertainty on the complex stability. Indeed, large discrepancies are observed for a given complex in the cyclodextrin literature. There is a lack of a generalized scheme for the measurement of affinity. Therefore, this chapter reviews the common experimental approaches and proposes a unified framework for measuring binding constants of cyclodextrins inclusion compounds. This unified approach relies on the use of minimization algorithms and is decomposed into major associated concepts, with the description of experimental protocols, equilibriums, analytical methods and data treatments. The chapter discusses the concept of global analysis and the issues of stability accuracy, optimization of experimental conditions and evaluation of thermodynamic parameters. Future research will probably focus on the generalization of algorithmic treatments, global analysis and statistical evaluation.
    Mots-clés : Algorithmic treatment, Analytical techniques, Binding study, Cyclodextrins, Formation constant, Inclusion compounds, Remediation processes.

  • Lange B, Delhaye G, Boisson S, Verbruggen N, Meerts P, Faucon M-P. Variation in copper and cobalt tolerance and accumulation among six populations of the facultative metallophyte Anisopappus chinensis (Asteraceae). Environmental and Experimental Botany 2018; 153: 1-9.
    Résumé : Advances on the ecology and evolution of adaptation to metal toxicity are based on studying metallophytes that are not restricted to soils strongly enriched in trace elements. The evolution of Cu and Co tolerance and accumulation, which principally occurs among the Copperbelt of Central Africa, is poorly known. In this paper, we studied Cu and Co tolerance and accumulation in a facultative metallophyte occupying a very broad ecological niche in southeastern Democratic Republic of Congo: Anisopappus chinensis (Asteraceae). The population variation in Cu and Co tolerance and accumulation was experimentally investigated using four metallicolous and two non-metallicolous populations from contrasted habitats. Surprisingly, Cu tolerance was poorly expressed in metallicolous populations grown in hydroponics, suggesting that specific rhizosphere processes may account for the ability to grow without toxicity symptoms under high Cu concentration on metalliferous soils. Population variation in Co tolerance and accumulation was demonstrated, which positively correlated to the concentration of Co in the native soil. Increased tolerance seems to have evolved in populations originating from Co-enriched soils. Foliar Co accumulation above 300 mg kg−1 dry weight with increased translocation was observed in the most tolerant populations, possibly making such populations promising materials to test for Co-phytomining applications.
    Mots-clés : Hyperaccumulation, Intraspecific variation, Metallicolous, Non-metallicolous, Plant evolution.

  • Ledoux F, Roche C, Cazier F, Beaugard C, Courcot D. Influence of ship emissions on NOx, SO2, O3 and PM concentrations in a North-Sea harbor in France. Journal of Environmental Sciences 2018; 71: 56-66.

  • Luzuriaga W patricio, Schellenberger R, De Gaetano Y, et al. Synthetic Rhamnolipid Bolaforms trigger an innate immune response in Arabidopsis thaliana | Scientific Reports. 2018. (consulté 6 sept.2018).
    Résumé : Stimulation of plant innate immunity by natural and synthetic elicitors is a promising alternative to conventional pesticides for a more sustainable agriculture. Sugar-based bolaamphiphiles are known for their biocompatibility, biodegradability and low toxicity. In this work, we show that Synthetic Rhamnolipid Bolaforms (SRBs) that have been synthesized by green chemistry trigger Arabidopsis innate immunity. Using structure-function analysis, we demonstrate that SRBs, depending on the acyl chain length, differentially activate early and late immunity-related plant defense responses and provide local increase in resistance to plant pathogenic bacteria. Our biophysical data suggest that SRBs can interact with plant biomimetic plasma membrane and open the possibility of a lipid driven process for plant-triggered immunity by SRBs.

  • Mallard I, Bourgeois D, Fourmentin S. A friendly environmental approach for the controlled release of Eucalyptus essential oil. Colloids and Surfaces A: Physicochemical and Engineering Aspects 2018; 549: 130-137.
    Résumé : The latest health scandals lead to improve treatment of patients using alternative ways more concerned with the environment and human health. The use of ecological systems represents a safe approach for their uses in medical application. Delivery system encapsulating Eucalyptus essential oil (EEO) could be an alternative approach to fight against bacterial, inflammatory, pyretic and respiratory infections. In this study, we report the synthesis of three zeolites Y covalently grafted with β-cyclodextrins using succinic, adipic and citric acid as croslinker. The morphology, thermal property, porosity, chemical composition and yield of grafting were determined to fully characterize these new materials. The values obtained in BET show a marked decrease of specific surface area, characteristic of a change in the zeolite structure. The ability of the obtained zeolite to progressively release EEO was investigated by multiple headspace extraction (MHE). The results demonstrated that obtained zeolites were able to encapsulate EEO more efficiently than free β-cyclodextrin and to decrease their release kinetics. Thus, these new friendly materials can find applications to improve the use of essential oils in aromatherapy, cosmetic or medicine.
    Mots-clés : Eucalyptus essential oil, Release studies, Zeolite, β-Cyclodextrin.

  • Marie T, Willig G, Teixeira ARS, et al. Enzymatic synthesis of resveratrol α-glycosides from β-cyclodextrin-resveratrol complex in water. ACS Sustainable Chem. Eng. 2018. doi:10.1021/acssuschemeng.8b00176.
    Résumé : Although resveratrol (3,5,4′-trihydroxy-stilbene) is one of the most studied natural product because of its biological properties such as antioxidant or anticancer, its low water solubility and stability (influenced by pH, light and increased temperature), as well as its propensity to oligomerize, limit its bioavailability and applications in nutraceutic, cosmetics or pharmaceutical industries. Besides, resveratrol production at the multigram scale through vine cell culture is limited by the tedious extraction of pure resveratrol from the bioconversion medium due to its complexation by cyclodextrins, the latter being used as elicitors in the bioproduction process. In this work, we have been able to overcome all these drawbacks by performing a single organic solvent-free enzymatic α-glycosylation directly from the β-cyclodextrin-resveratrol complex in water using β-cyclodextrin as glycoside-donor. The combined effects of five parameters (CGTase amount, cyclodextrin amount, cyclodextrin/resveratrol ratio, pH, and temperature) were studied by design of experiments (DoE) to maximize the glycosylation yield. The optimal setting point of parameters was obtained by response surface methodology (RSM). After optimization, an efficient α-glycosylation was performed being obtained 35% of molar yield. The major glycosides—two monoglycosides: 3-O-α-d-glucosyl-resveratrol and 4′-O-α-d-glucosyl-resveratrol and two diglycosides: 3-O-α-d-maltosyl-resveratrol and 4′-O-α-d-maltosyl-resveratrol—were characterized using a hyphenated liquid chromatography-solid phase extraction-nuclear magnetic resonance system, then separated and purified using centrifugal partition chromatography (CPC). Their antiradical properties, as well as that of their crude mixture, were evaluated through DPPH analysis. Results confirmed that the position 4′–OH is the best position for the glycosylation to maintain the highest antiradical properties.

  • Meglouli H, Lounès-Hadj Sahraoui A, Magnin-Robert M, Tisserant B, Hijri M, Fontaine J. Arbuscular mycorrhizal inoculum sources influence bacterial, archaeal, and fungal communities' structures of historically dioxin/furan-contaminated soil but not the pollutant dissipation rate. Mycorrhiza 2018. doi:10.1007/s00572-018-0852-x.
    Résumé : Abstract: Little is known about the influence of arbuscular mycorrhizal fungi (AMF) inoculum sources on phytoremediation efficiency. Therefore, the aim of...
    Mots-clés : Dioxins/furans, Inoculum sources, Microbial community, Mycorrhizae, Phytoremediation.

  • Monnier N, Furlan A, Botcazon C, et al. Rhamnolipids From Pseudomonas aeruginosa Are Elicitors Triggering Brassica napus Protection Against Botrytis cinerea Without Physiological Disorders. Frontiers in Plant Science 2018; 9. doi:10.3389/fpls.2018.01170.
    Résumé : Rhamnolipids (RLs) are amphiphilic molecules naturally produced by some bacteria with a large range of biological activities. Although some studies report their potential interest in plant protection, evaluation of their effects and efficiency on annual crops of worldwide agronomic interest is lacking. The main objective of this work was to investigate their elicitor and protective activities on rapeseed crop species while evaluating their physiological effects. Here we report that RLs from Pseudomonas aeruginosa secretome trigger an effective protection of Brassica napus foliar tissues toward the fungus Botrytis cinerea involving the combination of plant defense activation and direct antimicrobial properties. We demonstrated their ability to activate canonical B. napus defense responses including reactive oxygen species production, expression of defense genes, along with callose deposits and stomatal closure as efficient physical protections. In addition, microscopic cell death observations and electrolyte leakage measurements indicated that RLs trigger a hypersensitive response-like defense in this plant. We also showed that foliar spray applications of RLs do not induce deleterious physiological consequences on plant growth or chlorophyll content and that RL protective properties are efficient on several grown cultivars of rapeseed. To our knowledge, this is the first report of RLs as an elicitor that suppresses fungal disease on tissues of an annual crop species under greenhouse conditions. Our results highlight the dual mode of action of these molecules exhibiting plant protection activation and antifungal activities and demonstrate their potential for crop cultures as environmental-friendly biocontrol solution.
    Mots-clés : Bassica napus, biocontrol, defense responses, elicitor, Plant Immunity, rhamnolipids.

  • Morin-Crini N, Winterton P, Fourmentin S, Wilson LD, Fenyvesi É, Crini G. Water-insoluble β-cyclodextrin–epichlorohydrin polymers for removal of pollutants from aqueous solutions by sorption processes using batch studies: A review of inclusion mechanisms. Progress in Polymer Science 2018; 78: 1-23.
    Résumé : Although water-insoluble cyclodextrin-epichlorohydrin polymers have been known for half a century, these materials are of continued interest to the scientific community, in particular for their interesting environmental applications as sorbents in liquid-solid sorption processes. However, in spite of the abundance of literature and conclusive results obtained at the laboratory scale, interpreting the mechanisms of pollutant elimination remains an interesting source of debate and sometimes of contradiction. This review summarizes and discusses the various mechanisms proposed in the literature. A distinction was made in the description of these interactions depending on whether the polymer structures were modified or not.
    Mots-clés : Cross-linking, Cyclodextrin, Epichlorohydrin, Mechanisms, Pollutants, Polymer.

  • Morvan X, Verbeke L, Laratte S, Schneider A. Impact of recent conversion to organic farming on physical properties and their consequences on runoff, erosion and crusting in a silty soil. CATENA 2018; 165: 398-407.
    Résumé : The aim of this study was to assess the influence of a recent conversion to organic farming on the physical properties, particularly the aggregate stability, of soils that are prone to soil crusting, as well as their impact on runoff, soil erosion and soil crusting dynamics. Experiments were conducted in the area of Brie, France, in two agricultural fields separated by 400 m with similar slopes and soil types. They consisted of physical measurements of the soils as well as simulated rainfalls with different intensities. No significant differences were detected among the bulk density, soil water retention or saturated hydraulic conductivity. The aggregate stability, measured both under simulated rainfall and in a laboratory, was significantly higher in the organic management field (OF) than in the conventional management field (CM), indicating that CM soils are more prone to soil crusting than OF soils. The influence of this difference was quantified using rainfall simulations in the field. Within the CM field, runoff occurred with a runoff coefficient (RC) of 4.8% and 6.9% when the rainfall intensities were 25 and 40 mm h−1, respectively, while in the OF field, no runoff was observed at these intensities. However, slight runoff was observed when the intensity was 50 mm h−1. Soil losses followed the same trend. Depositional soil crusts were observed in the plots wherein runoff transpired. These results evidence the benefits of recent conversion to organic farming in silty soil to the aggregate stability and consequently soil crust dynamics, runoff genesis and soil erosion.
    Mots-clés : Aggregate stability, Agricultural practices, Simulated rainfall, Soil loss, Soil physical properties.

  • Niang I, Maalouf C, Moussa T, et al. Hygrothermal performance of various Typha–clay composite. Journal of Building Physics 2018; : 1744259118759677.
    Résumé : This article deals with the influence of both morphology and amount of Typha on hygrothermal behavior of a Typha–clay composite for building application. An agromaterial containing the fiber mix of Typha Australis and clay was made in three samples: three fiber mixtures were prepared with different amounts Typha and cut type (transversal or longitudinal). The physical properties of these materials were studied in terms of porosity, apparent and absolute density, thermal conductivity, and hygric properties. Results show a real impact of the Typha fraction type and its volume content on hygrothermal properties of the studied material due to the porosity. The transversal fraction of Typha (80% in volume weight) seems to be the optimal composition for a better hygrothermal behavior.

  • Oliva E, Mathiron D, Bertaut E, et al. Physico-chemical studies of resveratrol, methyl-jasmonate and cyclodextrin interactions: an approach to resveratrol bioproduction optimization. RSC Advances 2018; 8: 1528-1538.
    Mots-clés : APR 2014, Axe 1, Axe 2, culture cellulaire, cyclodextrine, methyl jasmonate, process, production, Projet CYCLORESVE, resvératrol, Suite projet SFR.

  • Pozzobon V, Colin J, Perré P. Hydrodynamics of a packed bed of non-spherical polydisperse particles: A fully virtual approach validated by experiments. Chemical Engineering Journal 2018; 354: 126-136.
    Résumé : This work presents a numerical workflow to generate a virtual packed bed made of non-spherical polydisperse particles, and subsequently predict its permeability. Wood chips were taken as an illustration. First, chips are sized before being recreated numerically. Then, using LMGC90, a DEM code, a packed bed made of those chips was generated. Once bed internal had been sampled, CFD tools belonging to the OpenFOAM library were used to mesh the geometry (snappyHexMesh) and compute fluid motion (simpleFoam). Finally, using numerical results, the bed permeability was computed in both Stokes and inertial regimes - turbulence being described by Launder-Reece-Rodi model. In parallel, experimental measurements of the permeability of a packed bed, made of the exact same wood chips, was carried out. These experiments were used as a reference to challenge numerical results. The permeability value delivered by the workflow is 16.0% higher than the experimental value. This value has to be compared with Kozeny-Carman equation estimation which overestimates bed permeability by 115%. Going one step further, this framework was successfully used to compute inertial effects constant of the Forshheimer equation for our packed bed. Throughout this article, a special care has been taken in explaining and evaluating the impact of all the key parameters, namely, number of particles that have to be sized, mesh refinement level, numerical domain dimensions. This workflow opens the door to numerical estimation of bed tortuosity, dispersion coefficients, volumetric heat exchange coefficients, and much more, using the particle size distribution as unique input data.
    Mots-clés : CFD, DEM, Granular media, OpenFOAM, Permeability, Porous media.

  • Pozzobon V, Perre P. Han’s model parameters for microalgae grown under intermittent illumination: Determined using particle swarm optimization. Journal of Theoretical Biology 2018; 437: 29-35.
    Résumé : This work provides a model and the associated set of parameters allowing for microalgae population growth computation under intermittent lightning. Han’s model is coupled with a simple microalgae growth model to yield a relationship between illumination and population growth. The model parameters were obtained by fitting a dataset available in literature using Particle Swarm Optimization method. In their work, authors grew microalgae in excess of nutrients under flashing conditions. Light/dark cycles used for these experimentations are quite close to those found in photobioreactor, i.e. ranging from several seconds to one minute. In this work, in addition to producing the set of parameters, Particle Swarm Optimization robustness was assessed. To do so, two different swarm initialization techniques were used, i.e. uniform and random distribution throughout the search-space. Both yielded the same results. In addition, swarm distribution analysis reveals that the swarm converges to a unique minimum. Thus, the produced set of parameters can be trustfully used to link light intensity to population growth rate. Furthermore, the set is capable to describe photodamages effects on population growth. Hence, accounting for light overexposure effect on algal growth.
    Mots-clés : Han’s model, Light, Microalgae, Modeling, Population growth rate.

  • Rabhi NEH, Silini A, Cherif‐Silini H, et al. Pseudomonas knackmussii MLR6, a rhizospheric strain isolated from halophyte, enhances salt tolerance in Arabidopsis thaliana. Journal of Applied Microbiology 2018. doi:10.1111/jam.14082.
    Résumé : Aims The study aimed for evaluate the efficacy of Pseudomonas knackmussii MLR6 on growth promotion, photosynthetic responses, pigment contents and gene expression of the plant model Arabidopsis thaliana under NaCl stress. Methods and Results The strain MLR6 was isolated from the rhizopshere of the halophyte Salsola tetrandra collected from a natural saline Algerian soil. Results showed the ability of MLR6 to induce plant growth promoting traits even under NaCl stress. The inoculation with MLR6 improved the stomatal conductance, the transpiration rate, the total chlorophyll and carotenoids contents under salt stress. It conferred also an increase of fresh/dry weight as well as plant height. MLR6 inoculation further provided a positive effect on cell membrane stability by reducing the electrolyte leakage and priming the ROS accumulation after the salt exposition. Additionally, the expression of NHX1, HKT1, SOS2, and SOS3 as well as SAG13 and PR1 was maintained in MLR6-bacterized plant at a similar level of controls. Conclusions The inoculation of Arabidopsis thaliana with MLR6 improves plant growth and reduces damages caused by salt stress. Significance and Impact of Study The use of Pseudomonas knackmussii MLR6 appears as a promising strategy to improve the sustainable agriculture under saline conditions. This article is protected by copyright. All rights reserved.
    Mots-clés : Arabidopsis thaliana, defense, halophyte, PGPR, photosynthesis, salt stress.

  • Samaï H-C, Rioult D, Bado-Nilles A, et al. Procedures for leukocytes isolation from lymphoid tissues and consequences on immune endpoints used to evaluate fish immune status: A case study on roach (Rutilus rutilus). Fish & Shellfish Immunology 2018; 74: 190-204.
    Résumé : The effects of two protocols (density gradient versus hypotonic lysis) used for leukocyte isolation from three major lymphoid tissue of fish (head-kidney, spleen and blood) were examined on some cell functional activities (tissue leucocytes distributions, phagocytosis, basal and burst oxidative activities) classically used to estimate the fish immune status. Experiments were conducted on roach (Rutilus rutilus), a cyprinid fish model often studied in different eco-physiological contexts (aquaculture, ecotoxicology …). All of immune endpoints were assessed either immediately after cell isolation or after a 12 h of incubation in order to observe if a post-isolation incubation may influence the leukocytes activities. Compared to the density gradient, hypotonic lysis is associated with granulocytes enrichments of cell suspensions. This is particularly true for leukocyte suspensions isolated from head kidney where granulocytes are naturally abundant. However, important variabilities in leukocyte distributions were observed in head kidney and spleen cells samples obtained by the use of hypotonic lysis for two incubation conditions used (no incubation or 12 h of incubation at 4 °C). The density gradient protocol leads to a transitory increase in basal ROS production in spleen lymphocytes and macrophages The blood leukocytes isolated by this same method exhibit high basal oxidative activities after 12 h of incubation at 4 °C and for the three leukocyte types (lymphocytes, monocytes and granulocytes). The hypotonic lysis is associated with an increase in PMA-induced ROS production especially in head kidney leukocytes. The increases in cell oxidative activities are consistent with increases in granulocyte proportions observed in leukocyte suspensions obtained by hypotonic lysis. Finally, the two protocols have no effect on leukocyte mortality and phagocytic activity. Within limits of our experimental conditions, the spleen is the organ whose leukocyte oxidative activities (stimulated or not) are only slightly influenced by the methods used for leukocyte isolation. This is also the case for the anterior kidney, but for this tissue, it is necessary to incubate the isolated cells for 12 h at 4 °C before functional analyses. Each of the two methodologies used has advantages and disadvantages. The hypotonic lysis allows to isolate a greater variety of leukocytes types whereas the density gradient used ensures a better stability of cells distributions over time. However, for the same fish species and for the same tissue, the method used to isolate leukocytes influences results and must be taken into consideration during acquired data analysis for evaluation of fish immune status.
    Mots-clés : Cell isolation, Density gradient, Erythrocytes lysis, Fish, Immunity, Leukocytes.

  • Siah A, Bomble M, Tisserant B, et al. Genetic Structure of Zymoseptoria tritici in Northern France at Region, Field, Plant, and Leaf Layer Scales. Phytopathology 2018; 108: 1114-1123.
    Résumé : Population genetic structure of the worldwide-distributed wheat pathogen Zymoseptoria tritici has been extensively studied at large geographical scales, but to a much less extent at small or local spatial scales. A total of 627 single-conidial fungal isolates were sampled from several locations in northern France (Hauts-de-France Region) to assess fungal genetic structure at region, field, plant, and leaf layer scales, using highly polymorphic microsatellite markers and mating type idiomorphs. Important and overall similar levels of both gene and genotype diversities (gene diversity values of ≥0.44 and haplotype frequencies of ≥94%) were found at all the examined scales. Such rates of diversity are likely due to an active sexual recombination in the investigated areas, as revealed by equal proportions of the two mating types scored in all sampled populations. Interestingly, a rare occurrence of clones among lesions from a same leaf, as well as among leaves from different plant leaf layers (e.g., upper versus lower leaves), was highlighted, indicating that ascospores contribute much more than expected to Z. tritici epidemics, compared with pycnidiospores. Population structure and analyses of molecular variance revealed significant genetic differentiation at the regional scale (GST = 0.23) and, as expected, not at the other more local scales (GST ≤ 0.01). Further analyses using Bayesian and unweighted neighbor-joining statistical methods detected six genetic clusters within the regional population, overall distributed according to the locations from which the isolates were sampled. Neither clear directional relative migration linked to the geographical distribution of the locations, nor isolation by distance, were observed. Separate evolutionary trajectories caused by selection and adaptations to habitat heterogeneity could be the main forces shaping such structuration. This study provides new insights into the epidemiology and the genetic structure of Z. tritici at small local and, for the first time, at single plant and leaf layer scales. Such findings would be helpful in implementing effective control strategies.

  • Smaoui H, Zouhri L, Kaidi S, Carlier E. Combination of FEM and CMA-ES algorithm for transmissivity identification in aquifer systems. Hydrological Processes 2018; 32: 264-277.
    Résumé : In this paper, we propose a coupling of a finite element model with a metaheuristic optimization algorithm for solving the inverse problem in groundwater flow (Darcy's equations). This coupling performed in 2 phases is based on the combination of 2 codes: This is the HySubF-FEM code (hydrodynamic of subsurface flow by finite element method) used for the first phase allowing the calculation of the flow and the CMA-ES code (covariance matrix adaptation evolution strategy) adopted in the second phase for the optimization process. The combination of these 2 codes was implemented to identify the transmissivity field of groundwater by knowing the hydraulic head in some point of the studied domain. The integrated optimization algorithm HySubF-FEM/CMA-ES has been validated successfully on a schematic case offering an analytical solution. As realistic application, the integrated optimization algorithm HySubF-FEM/CMA-ES was applied to a complex groundwater in the north of France to identify the transmissivity field. This application does not use zonation techniques but solves an optimization problem at each internal node of the mesh. The obtained results are considered excellent with high accuracy and fully consistent with the hydrogeological characteristics of the studied aquifer.However, the various numerical simulations performed in this paper have shown that the CMA-ES algorithm is time-consuming. Finally, the paper concludes that the proposed algorithm can be considered as an efficient tool for solving inverse problems in groundwater flow.
    Mots-clés : CMA-ES, finite element, Galerkin, hydraulic head, HySubF-FEM code, inverse problem, optimization, transmissivity.

  • Spiesser C, Pozzobon V, Farges O, Bézian J-J. Probabilistic modeling of coupled heat transfer: A step towards optimization based on multiphysics Monte Carlo simulations. International Journal of Thermal Sciences 2018; 132: 387-397.
    Résumé : This article presents a modular framework allowing to construct probabilistic models of coupled heat transfer problems in complex systems. First, a substructuring approach has been applied to formalize the problem. This process allowed for the coupling of physical field submodels, in our case temperature and radiative intensity. Each physical model was established according to the conservation law inside of its domain (solid and fluid) and the continuity laws at interfaces. Then, these models have been rewritten from the deterministic point of view to a probabilistic one. This enables a recursive Monte Carlo algorithm to estimate the desired values. After a validation stage, against academic cases, this framework is applied to examples emulating heat transfer in buildings. This approach presents a major beneficial behavior for complex systems optimization: only the influential parts of the problem have an effect on the computational time. These regions are automatically identified in a self-adaptive way, even in intricate or extensive geometries.
    Mots-clés : Coupling, Heat transfer, Monte Carlo method, Multiphysics, Self-adaptive.
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