Production éco-circulaire de peptides antibactériens, antifongiques et antioxydants déminéralisés à partir d'hémoglobine bovine par électrodialyse avec membranes bipolaires : étude de faisabilité, mécanisme enzymatique, optimisation des paramètres, comparaison avec l'hydrolyse conventionnelle et prévention du colmatage

Le cruor bovin, la matière solide du sang, est un déchet des abattoirs produit en très grande quantité dans le monde. Ce coproduit est composé principalement d'hémoglobine, une protéine riche en peptides bioactifs après son hydrolyse enzymatique. Cependant, lors de l'hydrolyse conventionnelle par la pepsine, des agents chimiques sont nécessaires pour ajuster et réguler le pH de la solution et, les hydrolysats finaux produits contiennent des niveaux élevés en sels minéraux. Pour pallier ces inconvénients, il a été proposé d'appliquer dans cette étude, pour la première fois, une technologie verte, appelée électrodialyse avec membrane bipolaire (EDMB), comme méthode alternative à l'hydrolyse enzymatique conventionnelle de l'hémoglobine afin d'obtenir des peptides bioactifs purifiés. Les objectifs de cette thèse étaient de tester la faisabilité de ce nouveau procédé pour la production de peptides bioactifs à partir d'hémoglobine bovine, d'établir les conditions optimales, d'éviter le colmatage membranaire et d'appliquer un nouveau procédé original d'EDMB à « multiple-étapes » permettant la production de peptides bioactifs déminéralisés sans ajout de produits chimiques. Des configurations bipolaires/monopolaires (anioniques ou cationiques) utilisant les ions H⁺ et OH⁻ générés par les membranes bipolaires pour réguler le pH ont été étudiées et comparées à un procédé conventionnel utilisant des acides et des bases chimiques. La configuration d'EDMB formée avec les membranes cationiques a permis la production d'hydrolysats contenant une faible concentration en sels minéraux mais avec la présence d'un colmatage sur la membrane cationique, alors que la configuration d'EDMB utilisant des membranes anioniques a permis la production d'hydrolysats sans colmatage mais avec une concentration en sel similaire à celle de l'hydrolyse conventionnelle (contrôle). En se basant sur ces résultats, une nouvelle configuration d'EDMB à trois compartiments a été mise en place et étudiée pour dénaturer l'hémoglobine, inactiver la réaction enzymatique et déminéraliser l'hydrolysat peptidique en simultané. Une déminéralisation de 85% a été atteinte. Cependant, un colmatage a encore été observé sur la membrane anionique en raison de la précipitation de l'hème. Pour cette raison, une étape supplémentaire de décoloration a été réalisée avant la déminéralisation pour éviter le colmatage en utilisant l'acide électro-généré. Les peptides décolorés et déminéralisés récupérés ont montré une activité antioxydante, une activité antibactérienne contre plusieurs souches bactériennes (Gram+ et Gram-) et pour la première fois une activité antifongique contre de nombreuses souches de moisissures et de levures. Dans un contexte d'économie circulaire, cette technologie durable s'avèrerait efficace pour effectuer plusieurs opérations simultanément et présente un potentiel important au niveau industriel pour l'hydrolyse du sang, puisqu'elle produit des bio-peptides purifiés ayant une faible teneur en sels minéraux et pouvant être utilisés comme conservateurs naturels sur la viande.Bovine cruor, a slaughterhouse waste, is produced in large quantities all around the world. This co-product is mainly composed of hemoglobin, a protein rich in bioactive peptides after its enzymatic hydrolysis. However, during conventional hydrolysis, chemical agents are necessary to adjust or regulate the pH of the solution and the final hydrolysates produced contain high levels of mineral salts. Therefore, in this study we applied for the first time a green technology named electrodialysis with bipolar membrane (EDBM) as an alternative method to the conventional enzymatic hydrolysis of hemoglobin to obtain purified bioactive peptides. The main objectives of the present thesis were to test the feasibility of this new process to produce bioactive peptides from bovine hemoglobin, to establish the optimal conditions while avoiding membrane fouling and to apply a new original « multiple-step » EDBM process allowing the production of demineralized bioactive peptides without the addition of chemical salts. Bipolar and monopolar (anionic or cationic) configurations using the H⁺ and OH⁻ generated by the bipolar membranes to regulate the pH were investigated and compared to a conventional process using chemical acid and base. The EDBM configuration formed with cationic membranes allowed the production of hydrolysates containing a low concentration of mineral salts but with fouling formation on the cationic membrane, while EDBM configuration formed with anionic membranes allowed the production of hydrolysates without fouling but with a salt concentration similar to the control. Based on these results, a new three-compartment EDBM configuration was carried-out to denaturate the hemoglobin, inactivate the enzymatic reaction, and demineralize the hemoglobin hydrolysate simultaneously. A demineralization level of 85% has been achieved. However, fouling was still observed on the anionic membrane due to hem precipitation. For this reason, an additional step of discoloration was tested before the demineralization to avoid fouling using the electrogenerated acid. The discolored and demineralized peptides recovered showed antioxidant activity, antibacterial activity against multiple bacterial strains (Gram+ and Gram-), and for the first time, antifungal activity against several molds and yeasts strains. Moving towards a circular economy, this sustainable technology was found to be effective in performing multiple operations simultaneously and has a great potential for industrial hydrolysis of blood, since it produces purified biopeptides with a low mineral content that can be used as natural preservatives on meat

Phenomenology of strangeness production at high energies

The strange-quark occupation factor ($\gamma_s$) is determined from the statistical fit of the multiplicity ratio $\mathrm{K}^+/\pi^+$ in a wide range of nucleon-nucleon center-of-mass energies ($\sqrt{s_{NN}}$). From this single-strange-quark-subsystem, $\gamma_s(\sqrt{s_{NN}})$ was parametrized as a damped trigonometric functionality and successfully implemented to the hadron resonance gas model, at chemical semi-equilibrium. Various particle ratios including $\mathrm{K}^-/\pi^-$, $\mathrm{\Lambda}/\pi^-$, and $\mathrm{\bar{\Lambda}}/\pi^-$ are well reproduced. The phenomenology of $\gamma_s(\sqrt{s_{NN}})$ suggests that, the hadrons ($\gamma_s$ raises) at $\sqrt{s_{NN}} \simeq 7~$GeV seems to undergo a phase transition to a mixed phase ($\gamma_s$ declines), which is then derived into partons ($\gamma_s$ remains unchanged with increasing $\sqrt{s_{NN}}$), at $\sqrt{s_{NN}} \simeq 20~$GeV.Comment: 6 pages, 2 figures, accepted for publication in EP

MODELLING TECHNIQUES FOR SLAB TRACK SYSTEMS

The railway slab track has replaced the ballast material in the classical ballasted track with reinforced concrete slab or asphalt layer to cope up with the increasing axle loads, train high-speeds, and to reduce overall maintenance cost. This paper aims to investigate the linear and nonlinear behavior of the most common slab track systems (BÖGL, Shinkansen, and RHEDA 2000) using American (AREMA) loads for different soil types to recommend the most suitable analysis type for each component of the slab track systems. Slab track Finite Element models have been built using Midas GTS NX software. The geometric model for each slab track type has been performed according to their standard section. The results of the analysis have indicated that, for BÖGL slab track, the difference of the rail displacement between the linear and nonlinear analysis is 26% meanwhile the differences of replacement layer stresses for BÖGL between linear and nonlinear are about 40 %. Concerning Shinkansen slab track, the difference of the rail deflection between the linear and nonlinear are 31% while the difference of replacement layer stresses for Shinkansen between linear and nonlinear is significantly huge about 65%. Regarding RHEDA 2000, the rail displacement variation between the linear and nonlinear is 16%. Concerning the replacement layer stresses variance for RHEDA 2000 between linear and nonlinear is about 46%. Changing the subgrade soil types has concluded that the nonlinear modelling should be utilized for the slab track substructure for poor, medium, and good soils while the linear modelling can be sufficient for very good soil types (rocks, gravel, etc.). Linear modelling can be enough to represent the analysis of the slab track superstructure to save computational cost. The railway slab track has replaced the ballast material in the classical ballasted track with reinforced concrete slab or asphalt layer to cope up with the increasing axle loads, train high-speeds, and to reduce overall maintenance cost. This paper aims to investigate the linear and nonlinear behavior of the most common slab track systems (BÖGL, Shinkansen, and RHEDA 2000) using American (AREMA) loads for different soil types to recommend the most suitable analysis type for each component of the slab track systems. Slab track Finite Element models have been built using Midas GTS NX software. The geometric model for each slab track type has been performed according to their standard section. The results of the analysis have indicated that, for BÖGL slab track, the difference of the rail displacement between the linear and nonlinear analysis is 26% meanwhile the differences of replacement layer stresses for BÖGL between linear and nonlinear are about 40 %. Concerning Shinkansen slab track, the difference of the rail deflection between the linear and nonlinear are 31% while the difference of replacement layer stresses for Shinkansen between linear and nonlinear is significantly huge about 65%. Regarding RHEDA 2000, the rail displacement variation between the linear and nonlinear is 16%. Concerning the replacement layer stresses variance for RHEDA 2000 between linear and nonlinear is about 46%. Changing the subgrade soil types has concluded that the nonlinear modelling should be utilized for the slab track substructure for poor, medium, and good soils while the linear modelling can be sufficient for very good soil types (rocks, gravel, etc.). Linear modelling can be enough to represent the analysis of the slab track superstructure to save computational cost

A Sociolinguistic Profile of English in Lebanon

This article provides an overview of the historical presence of foreign languages in Lebanon, focusing on language contact from the eighteenth century to date. Through sociolinguistic profiling, the paper describes the users and uses of English, as well as Lebanese attitudes towards English. The article begins by offering a general overview of the country, its languages and cultures, and its ethnic and religious groups. It presents a description of users of English along with a characterization of how the interpersonal, instrumental, regulative, and innovative functions of the language are manifested, while the final section of the article discusses attitudes to English in Lebanese society