Etude de la cinétique de formation d'une émulsion très concentrée huile dans eau en écoulement continu

Nous avons étudié expérimentalement les différentes étapes conduisant à la formation d'une émulsion très concentrée huile dans eau (% huile > 85) en écoulement continu. Le contrôle du mécanisme de rupture des gouttes est assuré par deux barreaux cylindriques insérés dans la conduite. Un fort rapport de viscosité existe entre les phases huile et eau. La mesure du couple résistant in-situ lors de l'émulsification et l'étude des tailles moyennes des gouttes et de leur distribution le long de la conduite ont permis de caractériser les temps caractéristiques des différentes étapes du procédé

Procédés basse énergie pour la production d'émulsions très concentrées huile dans eau : caractérisation, intensification et applications

High Internal Phase Ratio (HIPR) emulsions are encountered in a wide variety of industrial applications: agrochemicals, petrochemical, cosmetics etc. The aim of this study is to characterize a new low energy mixer called two-rod mixer (TRM). This TRM allows the creation in one step of HIPR emulsion of viscous oil (91%) in water. The different phases of the HIPR emulsification in the batch TRM (B-TRM) have been highlighted, as well as their characteristics times. We show that it is possible to control the droplet size distribution and so the properties of the HIPR made. Furthermore, the energy input during the emulsification is relatively low. Lastly, this batch process has been transposed in a continuous one (C-TRM) that conserves the main characteristics of the batch process: controlled production of uni-modal HIPR emulsion with a low energetic cost and without heating of fluids.Les émulsions très concentrées sont présentes dans de nombreux domaines tels que l'agroalimentaire ; la cosmétique ; la pétrochimie etc. L'enjeu de cette étude de thèse est de caractériser un nouveau type de mélangeur basse énergie appelé mélangeur à deux barreaux (MDB) permettant d'obtenir en une seule étape une émulsion très concentrée d'huile (91%) visqueuse dans de l'eau. Ce travail a permis de définir les grandes étapes et la cinétique de formation de ce type d'émulsion au sein de ce mélangeur deux barreaux en cuve (MDB-Cuv.). Il a également été montré que ce mélangeur permet de contrôler la taille des gouttes et donc les propriétés de l'émulsion formée tout en étant très compétitif d'un point de vue énergétique. Enfin, ce procédé en cuve a pu être adapté en continu (MDB-Cont.) tout en conservant ses principales caractéristiques : production contrôlée d'émulsion uni-modale à faible coût énergétique et sans échauffement des fluides. Mots clefs : Emulsions concentrées, Emulsification basse énergie, Procédé, Rhéologie des émulsions concentrées, Contrôle et caractérisation de la taille des gouttes, Intensification

Procédés basse énergie pour la production d émulsions très concentrées huile dans eau (caractérisation, intensification et applications.)

Les émulsions très concentrées sont présentes dans de nombreux domaines tels que l agroalimentaire ; la cosmétique ; la pétrochimie etc. L enjeu de cette étude de thèse est de caractériser un nouveau type de mélangeur basse énergie appelé mélangeur à deux barreaux (MDB) permettant d obtenir en une seule étape une émulsion très concentrée d huile (91%) visqueuse dans de l eau. Ce travail a permis de définir les grandes étapes et la cinétique de formation de ce type d émulsion au sein de ce mélangeur deux barreaux en cuve (MDB-Cuv.). Il a également été montré que ce mélangeur permet de contrôler la taille des gouttes et donc les propriétés de l émulsion formée tout en étant très compétitif d un point de vue énergétique. Enfin, ce procédé en cuve a pu être adapté en continu (MDB-Cont.) tout en conservant ses principales caractéristiques : production contrôlée d émulsion uni-modale à faible coût énergétique et sans échauffement des fluides.High Internal Phase Ratio (HIPR) emulsions are encountered in a wide variety of industrial applications: agrochemicals, petrochemical, cosmetics etc. The aim of this study is to characterize a new low energy mixer called two-rod mixer (TRM). This TRM allows the creation in one step of HIPR emulsion of viscous oil (91%) in water. The different phases of the HIPR emulsification in the batch TRM (B-TRM) have been highlighted, as well as their characteristics times. We show that it is possible to control the droplet size distribution and so the properties of the HIPR made. Furthermore, the energy input during the emulsification is relatively low. Lastly, this batch process has been transposed in a continuous one (C-TRM) that conserves the main characteristics of the batch process: controlled production of uni-modal HIPR emulsion with a low energetic cost and without heating of fluids.PAU-BU Sciences (644452103) / SudocSudocFranceF

La distomatose à Fasciola hepatica et le paludisme dans l'Ouest Médical (1948-1997)

RENNES1-BU Santé (352382103) / SudocSudocFranceF

“Labile” heme critically regulates mitochondrial biogenesis through Hap4p in Saccharomyces cerevisiae

International audienceEdited by Ruma Banerjee Heme (iron protoporphyrin IX) is a well-known prosthetic group for enzymes involved in metabolic pathways such as oxygen transport and electron transfer through the mitochondrial respiratory chain. However, heme has also been shown to be an important regulatory molecule (as "labile" heme) for diverse processes such as translation, kinase activity, and transcription in mammals, yeast, and bacteria. Taking advantage of a yeast strain deficient for heme production that enabled controlled modulation and monitoring of labile heme levels, here we investigated the role of labile heme in the regulation of mitochondrial biogenesis. This process is regulated by the HAP complex in yeast. Using several biochemical assays along with EM and epifluorescence microscopy, to the best of our knowledge, we show for the first time that cellular labile heme is critical for the post-translational regulation of HAP complex activity, most likely through the stability of the transcriptional co-activator Hap4p. Consequently, we found that labile heme regulates mitochondrial biogenesis and cell growth. The findings of our work highlight a new mechanism in the regulation of mitochondrial biogenesis by cellular metabolites

TMEM70 forms oligomeric scaffolds within mitochondrial cristae promoting in situ assembly of mammalian ATP synthase proton channel

Mitochondrial ATP-synthesis is catalyzed by a F1Fo-ATP synthase, an enzyme of dual genetic origin enriched at the edge of cristae where it plays a key role in their structure/stability. The enzyme’s biogenesis remains poorly understood, both from a mechanistic and a compartmentalization point of view. The present study provides novel molecular insights into this process through investigations on a human protein called TMEM70 with an unclear role in the assembly of ATP synthase. A recent study has revealed the existence of physical interactions between TMEM70 and the subunit c (Su.c), a protein present in 8 identical copies forming a transmembrane oligomeric ring (c-ring) within the ATP synthase proton translocating domain (F O ). Herein we analyzed the ATP-synthase assembly in cells lacking TMEM70, mitochondrial DNA or F1 subunits and observe a reciprocal dependence of TMEM70 and Su.c levels, regardless of the status of other ATP synthase subunits or of mitochondrial bioenergetics. Immunoprecipitation and two-dimensional blue-native/SDS-PAGE reveal that TMEM70 forms large oligomers composed of 8 TMEM70 dimers and that TMEM70 oligomers interact with Su.c not yet incorporated into ATP synthase complexes. Moreover, discrete TMEM70-Su.c complexes with increasing Su.c contents can be detected, suggesting a role for TMEM70 oligomers in the gradual assembly of the c-ring. Furthermore, we demonstrate using expansion super-resolution microscopy the specific localization of TMEM70 at the inner cristae membrane, distinct from the MICOS component MIC60. Taken together, our results show that TMEM70 oligomers provide a scaffold for c-ring assembly and that mammalian ATP synthase is assembled within inner cristae membranes

Radical cystectomy or bladder preservation with radiochemotherapy in elderly patients with muscle-invasive bladder cancer: Retrospective International Study of Cancers of the Urothelial Tract (RISC) Investigators

IF 3.156International audienceBackground: Radical cystectomy (RC) and radiochemotherapy (RCT) are curative options for muscle-invasive bladder cancer (MIBC). Optimal treatment strategy remains unclear in elderly patients.Material and methods: Patients aged 80 years old and above with T2-T4aN0-2M0-Mx MIBC were identified in the Retrospective International Study of Cancers of the Urothelial Tract (RISC) database. Patients treated with RC were compared with those treated with RCT. The impact of surgery on overall survival (OS) was assessed using a Cox proportional hazard model. Progression included locoregional and metastatic relapse and was considered a time-dependent variable.Results: Between 1988 and 2015, 92 patients underwent RC and 72 patients had RCT. Median age was 82.5 years (range 80–100) and median follow-up was 2.90 years (range 0.04–11.10). Median OS was 1.99 years (95%CI 1.17–2.76) after RC and 1.97 years (95%CI 1.35–2.64) after RCT (p = .73). Median progression-free survival (PFS) after RC and RCT were 1.25 years (95%CI 0.80–1.75) and 1.52 years (95%CI 1.01–2.04), respectively (p = .54). In multivariate analyses, only disease progression was significantly associated with worse OS (HR = 10.27 (95%CI 6.63–15.91), p < .0001). Treatment modality was not a prognostic factor.Conclusions: RCT offers survival rates comparable to those observed with RC for patients aged ≥80 years

Radical cystectomy or bladder preservation with radiochemotherapy in elderly patients with muscle-invasive bladder cancer: retrospective international study of cancers of the urothelial tract (RISC) investigators

Background: radical cystectomy (RC) and radiochemotherapy (RCT) are curative options for muscle-invasive bladder cancer (MIBC). Optimal treatment strategy remains unclear in elderly patients.Material and methods: patients aged 80 years old and above with T2-T4aN0-2M0-Mx MIBC were identified in the Retrospective International Study of Cancers of the Urothelial Tract (RISC) database. Patients treated with RC were compared with those treated with RCT. The impact of surgery on overall survival (OS) was assessed using a Cox proportional hazard model. Progression included locoregional and metastatic relapse and was considered a time-dependent variable.Results: between 1988 and 2015, 92 patients underwent RC and 72 patients had RCT. Median age was 82.5 years (range 80-100) and median follow-up was 2.90 years (range 0.04-11.10). Median OS was 1.99 years (95%CI 1.17-2.76) after RC and 1.97 years (95%CI 1.35-2.64) after RCT (p = .73). Median progression-free survival (PFS) after RC and RCT were 1.25 years (95%CI 0.80-1.75) and 1.52 years (95%CI 1.01-2.04), respectively (p = .54). In multivariate analyses, only disease progression was significantly associated with worse OS (HR = 10.27 (95%CI 6.63-15.91), p &lt; .0001). Treatment modality was not a prognostic factor.Conclusions: RCT offers survival rates comparable to those observed with RC for patients aged ≥80 years.</p