Influence of γ-irradiated biopharmaceutical films

Preventing cross-contamination, saving costs and increasing configuration flexibility make the adoption of single-use technologies very attractive for the biopharmaceutical industry. The integrity and the security of bags are due to appropriate flexible and barrier polymeric materials, such as polyethylene (PE) or ethylene vinyl acetate (EVA) and polyethylene-co-vinyl alcohol (EVOH), which are barrier to water vapor and oxygen, respectively. Conventional stainless steel tanks are sterilized by steam sterilization by the end-users, whereas plastic containers are sterilized by gamma-irradiation before delivery. The major advantage of radio-sterilization is the penetration power of the γ-radiation. It is known that γ -sterilization of polyolefin based polymer leads to alterations of the material: changes in the additives or potential damage to the polymer, as reported in the literature. Irradiation of polymeric materials has been proven to initiate radiation chemical reactions inside the polymeric material, leading to either an increase or a decrease in the polymer molecular weight. The effects of γ-irradiation on polymers are well known whereas the effects of γ-irradiation on multilayer films have been little investigated. In the case of multilayer films, the acidity of the stored solution increased after gamma irradiation for instance. In another case oxidation of the solution occurred. Such observations denote the presence of acidic and oxidant compounds, which are issued either from modification of surface of the film or from the migration of by-products from core to surface. A global investigation on γ-irradiation on multilayer films is performed to investigate the γ-irradiation based modifications on PE(Polyethylene)/EVOH(Ethylene Vinyl Alcohol)/PE film and EVA(Ethylene Vinyl Acetate)/EVOH/EVA film to assess the multilayer film robustness. Several approaches could be used to study the impact of γ-irradiation on multilayer films, as ESR (Electron Spin Resonance) to observe the radicals formation, ATR-FTIR (Attenuated Total Reflection-Fourier Transform Infrared) and Raman spectroscopies to observe the structural modifications, the measurement of yellowing, the measurement of O2 transmission rate (O2TR) and water vapor transmission rate (WVTR), the measurement of pH to follow the acidity change of solution contained in the bag and the mechanical test to evaluate the toughness of film. Due to the number of data recorded, chemometric methods, such as Principal Component Analysis (PCA), are applied to enhance the weak variations brought to the γ-irradiation of the multilayer films in the different data sets. Results show that films undergo modifications at microscopic level and that they are not altered from macroscopic and application viewpoints. Results are equivalent from batch to batch assuring then a reproducibility of the films behavior for their integration in single-use systems

pH evolution in solution after contact with multilayer films after different g- irradiation doses and thus reconciliation of pH and TOC with carboxylic acids detected by ion chromatography

For a number of various uses (storage, mixing, freezing, transportation, formulation, and filling) biopharmaceutical solutions are stored in sterile single-use plastic bags. Material transfers can then occur between containers and contents. These migrations, of different types, depend on the physicochemical characteristics of the material (composition, pH, solubility, viscosity, molecular weight, etc.), the nature of the product (solid, semi-solid and liquid) and the conditions of the material utilization. In the case of single-use polymers, γ-irradiation sterilization of the polymer is often carried out. The interactions could be therefore influenced by the dose and the contact time between the container and the contents. γ-sterilization of single-use systems initiates chemical reactions and complex modifications inside the plastic material, In this study, γ-irradiation doses investigated are up to 270 kGy in order to emphazise the γ-irradiation effect and to better investigate the modifications of commercial PE(Polyethylene)/EVOH(Ethylene Vinyl Alcohol)/PE-film and commercial EVA(Ethylene Vinyl Acetate)/EVOH/EVA film. This study is a part of a global investigation on γ-irradiation on multilayer films Non-specific (TOC, pH, conductivity) or specific (e.g. chromatographic, spectroscopic, gravimetric) analytical methods can be used. several approaches were used to study the impact of γ-irradiation on multilayer films, as ion chromatography to detect and quantify the ionic species, and as pH and conductivity measurements to observe the consequences of the chemical modifications.. There are few references available on the leaching of carboxylic acid species impacting aqueous solutions used in biopharmaceutical applications in contact with plastic single-use systems [[i]]. Stability studies under accelerated or real-time degradation conditions make it possible to define the shelf life and storage conditions in order to guarantee the quality of the product. The aim of the study is to identify and quantify the acid compounds that can be released from the container under normal conditions of use of the materials: the extractables. [[1]] D. Jenke, D and V.J. Barge. Factors affecting the release of extractable acetic acid from multi-layered plastic films containing ethylene vinyl acetate (EVA) and polyethylene (PE) layers. Pharm Outsourcing. 15 (2014) 56-59

Effects of dynamic cell culture conditions on 3D spatial reogarnization of MSCS/HUVECS spheroids in the context of bone tissue

We aim to observe the development and reorganization of MSCs and HUVECs in Pullulan/Dextran hydrogels supplied with nHAp under dynamic culture conditions in a perfusion bioreactor.Hydrogel poreux sous perfusion : modélisation et optimisation d'un modèle in vitro de reconstruction de défaut osseu

Human granzyme B regulatory B cells prevent effector CD4+CD25- T cell proliferation through a mechanism dependent from lymphotoxin alpha

IntroductionHuman Granzyme B (GZMB) regulatory B cells (Bregs) have suppressive properties on CD4+ effector T cells by a mechanism partially dependent on GZMB. Moreover, these cells may be easily induced in vitro making them interesting for cell therapy.MethodsWe characterized this population of in vitro induced GZMB+Bregs using single cell transcriptomics. To investigate their regulatory properties, Bregs or total B cells were also co-cultured with T cells and scRNAseq was used to identify receptor ligand interactions and to reveal gene expression changes in the T cells.ResultsWe find that Bregs exhibit a unique set of 149 genes differentially expressed and which are implicated in proliferation, apoptosis, metabolism, and altered antigen presentation capacity consistent with their differentiated B cells profile. Notably, Bregs induced a strong inhibition of T cell genes associated to proliferation, activation, inflammation and apoptosis compared to total B cells. We identified and validated 5 receptor/ligand interactions between Bregs and T cells. Functional analysis using specific inhibitors was used to test their suppressive properties and we identified Lymphotoxin alpha (LTA) as a new and potent Breg ligand implicated in Breg suppressive properties.DiscussionWe report for the first time for a role of LTA in GZMB+Bregs as an enhancer of GZMB expression, and involved in the suppressive properties of GZMB+Bregs in human. The exact mechanism of LTA/GZMB function in this specific subset of Bregs remains to be determined

Etude par simulations numériques instationnaires de l'écoulement dans les moteurs à propergol solide

This study focuses on the analysis of the laminar-turbulent transition of the flowfield in a channel with fluid injection through a porous wall. Such a configuration is representative of the flowfield inside solid rocket motors. The flowfield is obtained thanks to unsteady three-dimensional LES numerical computations. In order to trigger the transition from a laminar state to a turbulent one using LES approach, it turns out to be necessary to introduce some perturbation in the flowfield. This study concentrates on searching a method to generate such perturbations. A first attempt has been made using the properties of the numerical scheme of the CEDRE CFD code of ONERA. A second approach that enables to take into account some experimental data has been developed. The experimental data is provided from the VECLA cold-gas setup of ONERA. This second method is based on the stochastic model from the Langevin equation. This equation has been implemented in the CEDRE code. A numerical study of the behaviour of such a model for the simulation of the transitional state of the flowfield obtained in channel with fluid injection through a porous wall has been done. The three-dimensional unsteady LES simulations of the flowfield in the VECLA setup have then been carried out using the CEDRE code. The results have been compared with the experimental data and with the results from a RANS computation. The benefit of using the stochastic equation of Langevin for the simulation of the turbulent quantities of such a flowfield has been pointed out.Cette étude est consacrée à l'analyse par simulations numériques instationnaires tridimensionnelles LES de la transition laminaire-turbulent dans un canal à injection pariétale représentatif de l'écoulement dans les chambres de moteurs à propergol solide. Pour déclencher le phénomène de transition vers la turbulence avec la méthode LES, il a été nécessaire d'introduire des fluctuations dans l'écoulement. Cette étude se focalise sur la recherche d'une méthodologie de calcul permettant de générer des perturbations dans l'écoulement. Une première méthode, basée sur le comportement du schéma numérique du code de calcul CEDRE de l'ONERA, a été utilisée pour générer des fluctuations dans l'écoulement. Une deuxième méthode prenant en compte les données expérimentales relevées sur le montage en gaz froid VECLA de l'ONERA a ensuite 't' développée. Cette dernière utilise une modélisation stochastique dans le cadre de l'equation de Langevin. Après implantation de cette méthode de calcul stochastique dans le code CEDRE, une étude spécifique a été menée pour analyser le comportement du modèle en relation avec la problématique de l'écoulement transitionnel dans le canal avec injection pariétale. Les simulations numériques instationnaires LES de l'écoulement en transition dans le montage VECLA ont ensuite été réalisées avec le code de calcul CEDRE. Les résultats ont été confrontés aux données expérimentales ainsi qu'a une simulation stationnaire RANS de l'écoulement. Les résultats mettent en évidence l'intérêt de la modélisation stochastique de Langevin sur la description du champ fluctuant dans le canal avec injection pari'etale

Soins palliatifs des douleurs liées aux métastases osseuses pulmonaires des cancers broncho-pulmonaires par Samarium 153-EDTMP (Quadramet®) (à propos de huit cas)

PARIS6-Bibl.Pitié-Salpêtrie (751132101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Etude par simulations numériques instationnaires de l'écoulement dans les moteurs à propergol solide

Cette étude est consacrée à l'analyse par simulations numériques instationnaires tridimensionnelles LES de la transition laminaire-turbulent dans un canal à injection pariétale représentatif de l'écoulement dans les chambres de moteurs à propergol solide. Pour déclencher le phénomène de transition vers la turbulence avec la méthode LES, il a été nécessaire d'introduire des fluctuations dans l'écoulement. Cette étude se focalise sur la recherche d'une méthodologie de calcul permettant de générer des perturbations dans l'écoulement. Une première méthode, basée sur le comportement du schéma numérique du code de calcul CEDRE de l'ONERA, a été utilisée pour générer des fluctuations dans l'écoulement. Une deuxième méthode prenant en compte les données expérimentales relevées sur le montage en gaz froid VECLA de l'ONERA a ensuite 't' développée. Cette dernière utilise une modélisation stochastique dans le cadre de l'equation de Langevin. Après implantation de cette méthode de calcul stochastique dans le code CEDRE, une étude spécifique a été menée pour analyser le comportement du modèle en relation avec la problématique de l'écoulement transitionnel dans le canal avec injection pariétale. Les simulations numériques instationnaires LES de l'écoulement en transition dans le montage VECLA ont ensuite été réalisées avec le code de calcul CEDRE. Les résultats ont été confrontés aux données expérimentales ainsi qu'a une simulation stationnaire RANS de l'écoulement. Les résultats mettent en évidence l'intérêt de la modélisation stochastique de Langevin sur la description du champ fluctuant dans le canal avec injection pariétale.This study focuses on the analysis of the laminar-turbulent transition of the flowfield in a channel with fluid injection through a porous wall. Such a configuration is representative of the flowfield inside solid rocket motors. The flowfield is obtained thanks to unsteady three-dimensional LES numerical computations. In order to trigger the transition from a laminar state to a turbulent one using LES approach, it turns out to be necessary to introduce some perturbation in the flowfield. This study concentrates on searching a method to generate such perturbations. A first attempt has been made using the properties of the numerical scheme of the CEDRE CFD code of ONERA. A second approach that enables to take into account some experimental data has been developed. The experimental data is provided from the VECLA cold-gas setup of ONERA. This second method is based on the stochastic model from the Langevin equation. This equation has been implemented in the CEDRE code. A numerical study of the behaviour of such a model for the simulation of the transitional state of the flowfield obtained in channel with fluid injection through a porous wall has been done. The three-dimensional unsteady LES simulations of the flowfield in the VECLA setup have then been carried out using the CEDRE code. The results have been compared with the experimental data and with the results from a RANS computation. The benefit of using the stochastic equation of Langevin for the simulation of the turbulent quantities of such a flowfield has been pointed out.POITIERS-ENS Mécanique Aérot (860622301) / SudocPOITIERS-BU Sciences (861942102) / SudocSudocFranceF

Direct numerical simulation of oxide inclusion turbulent deposition at liquid steel/slag interface

International audienceThe present study focuses on the inclusion behaviour near the liquid metal/slag interface. Inclusion turbulent deposition is investigated using direct numerical simulation of the liquid flow combined with Lagrangian particle tracking under conditions of one-way coupling. The interface is modelled as a non-deformable free-slip surface. Unsheared turbulence is generated by random forcing in a finite-height region parallel to the free-slip surface. In between, the turbulence diffuses toward the free surface. The inclusions are randomly introduced in the forcing region and tracked through the diffusion region up to the interface. In the particle dynamic equation, the buoyancy force, the Stokes drag, the pressure drag and the added mass are considered. Close to the interface, the hydrodynamic interactions (i.e. lubrication effects) between the inclusion and the free surface may be taken into account as well as the Van der Waals forces. Numerical simulations were performed with surface Reynolds numbers ranging from 68 to 235. The inclusion diameter varied between 10-5 m and 5.10-5 m and the particle to liquid density ratio between 0.5 and 1. For these sets of parameters, it appears that the inertia effects are very weak. The deposition of buoyant inclusions is controlled by sedimentation whereas for nonbuoyant inclusions, direct interception is the only deposition mechanism. In the latter case, the deposition velocity strongly depends on. It is shown that the deposition velocity made dimensionless by the free surface characteristic velocity scales as the inclusion diameter made dimensionless by the Kolmogorov length scale calculated at the free surface. Lastly, the effect of lubrication is examined: it can significantly reduce the direct interception contribution of the deposition velocity