Bidimensional lamellar assembly by coordination of peptidic homopolymers to platinum nanoparticles

A key challenge for designing hybrid materials is the development of chemical tools to control the organization of inorganic nanoobjects at low scales, from mesoscopic (~µm) to nanometric (~nm). So far, the most efficient strategy to align assemblies of nanoparticles consists in a bottom-up approach by decorating block copolymer lamellae with nanoobjects. This well accomplished procedure is nonetheless limited by the thermodynamic constraints that govern copolymer assembly, the entropy of mixing as described by the Flory–Huggins solution theory supplemented by the critical influence of the volume fraction of the block components. Here we show that a completely different approach can lead to tunable 2D lamellar organization of nanoparticles with homopolymers only, on condition that few elementary rules are respected: 1) the polymer spontaneously allows a structural preorganization, 2) the polymer owns functional groups that interact with the nanoparticle surface, 3) the nanoparticles show a surface accessible for coordination

Comparison of two analysis methods for nuclear reaction measurements of 12C +12C interactions at 95 MeV/u for hadrontherapy

During therapeutic treatment with heavier ions like carbon, the beam undergoes nuclear fragmentation and secondary light charged particles, in particular protons and alpha particles, are produced. To estimate the dose deposited into the tumors and the surrounding healthy tissues, the accuracy must be higher than ($\pm$3% and$\pm$1 mm). Therefore, measurements are performed to determine the double differential cross section for different reactions. In this paper, the analysis of data from 12C +12C reactions at 95 MeV/u are presented. The emitted particles are detected with \DeltaEthin-\DeltaEthick-E telescopes made of a stack of two silicon detectors and a CsI crystal. Two different methods are used to identify the particles. One is based on graphical cuts onto the \DeltaE-E maps, the second is based on the so-called KaliVeda method using a functional description of \DeltaE versus E. The results of the two methods will be presented in this paper as well as the comparison between both

Effect of the intermediate velocity emissions on the quasi-projectile properties for the Ar+Ni system at 95 A.MeV

The quasi-projectile (QP) properties are investigated in the Ar+Ni collisions at 95 A.MeV taking into account the intermediate velocity emission. Indeed, in this reaction, between 52 and 95 A.MeV bombarding energies, the number of particles emitted in the intermediate velocity region is related to the overlap volume between projectile and target. Mean transverse energies of these particles are found particularly high. In this context, the mass of the QP decreases linearly with the impact parameter from peripheral to central collisions whereas its excitation energy increases up to 8 A.MeV. These results are compared to previous analyses assuming a pure binary scenario

Study of intermediate velocity products in the Ar+Ni collisions between 52 and 95 A.MeV

Intermediate velocity products in Ar+Ni collisions from 52 to 95 A.MeV are studied in an experiment performed at the GANIL facility with the 4$\pi$ multidetector INDRA. It is shown that these emissions cannot be explained by statistical decays of the quasi-projectile and the quasi-target in complete equilibrium. Three methods are used to isolate and characterize intermediate velocity products. The total mass of these products increases with the violence of the collision and reaches a large fraction of the system mass in mid-central collisions. This mass is found independent of the incident energy, but strongly dependent on the geometry of the collision. Finally it is shown that the kinematical characteristics of intermediate velocity products are weakly dependent on the experimental impact parameter, but strongly dependent on the incident energy. The observed trends are consistent with a participant-spectator like scenario or with neck emissions and/or break-up.Comment: 37 pages, 13 figure

Measurements of sideward flow around the balance energy

Sideward flow values have been determined with the INDRA multidetector for Ar+Ni, Ni+Ni and Xe+Sn systems studied at GANIL in the 30 to 100 A.MeV incident energy range. The balance energies found for Ar+Ni and Ni+Ni systems are in agreement with previous experimental results and theoretical calculations. Negative sideward flow values have been measured. The possible origins of such negative values are discussed. They could result from a more important contribution of evaporated particles with respect to the contribution of promptly emitted particles at mid-rapidity. But effects induced by the methods used to reconstruct the reaction plane cannot be totally excluded. Complete tests of these methods are presented and the origins of the ``auto-correlation'' effect have been traced back. For heavy fragments, the observed negative flow values seem to be mainly due to the reaction plane reconstruction methods. For light charged particles, these negative values could result from the dynamics of the collisions and from the reaction plane reconstruction methods as well. These effects have to be taken into account when comparisons with theoretical calculations are done.Comment: 27 pages, 15 figure

The effects of siblings on the migration of women in two rural areas of Belgium and the Netherlands, 1829-1940

This study explores the extent to which the presence and activities of siblings shaped the chances of women migrating to rural and urban areas in two rural areas of Belgium and the Netherlands during the second half of the nineteenth and first decades of the twentieth century. Shared-frailty Cox proportional hazard analyses of longitudinal data from historical population registers show that siblings exerted an additive impact on women's migration, independently of temporal and household characteristics. Just how siblings influenced women's migration depended on regional modes of production and on employment opportunities. In the Zeeland region, sisters channelled each other into service positions. In the Pays de Herve, where men and women found industrial work in the Walloon cities, women were as much influenced by their brothers' activities. Evidence is found for two mechanisms explaining the effects of siblings: micro-economic notions of joint-household decision-making and social capital theory

Développement d'un vecteur lentiviral ciblant les astrocytes et mise en application dans l'étude des transporteurs au glutamate GLAST et GLT-1

Astrocytes are involved in key cerebral function such as synaptic transmission and neurometabolic coupling. Astrocytic glutamate transporters (GLAST and GLT-1) are decisive for these functions. Thus, their study is essential but few tools are specific and efficient to target astrocytes in vivo. We decide to develop a new lentiviral vector enable efficient transgene expression specifically in astrocytes. We develop three lines of research: Change the envelope of the vector, change the promoter and a new method of post-transcriptionnal regulation using microRNA. Our result shows that combining the Mokola envelope and target of a neuron-specific microRNA is a powerful tool to target astrocytes in vivo. The overexpression of GLAST, with this tool, induces a important neuroprotection in excitotoxic condition while inhibition of GLT-1 induces a diminution of cerebral metabolism. This new method to target astrocytes will permit a better understanding of astrocytes functions in vivo.Les astrocytes sont des cellules gliales jouant un rôle primordial dans le fonctionnement cérébral. Ils remplissent de nombreuses fonctions allant de la régulation de l'homéostasie ionique, à la modulation de la transmission synaptique en passant par la régulation du métabolisme énergétique. Les transporteurs astrocytaires au glutamate GLAST et GLT-1 tiennent un rôle particulièrement important dans ces fonctions astrocytaires. La recapture du glutamate libéré dans la synapse module la neurotransmission et évite la stimulation excessive des récepteurs glutamatergiques qui peut induire des phénomènes d'excitotoxicité provoquant la mort des neurones. Le couplage neurométabolique entre astrocytes et neurones repose également sur l'activité de ces transporteurs. De nombreuses données indiquent que des déficits des transporteurs au glutamate sont impliqués dans la plupart des maladies neurodégénératives. Les astrocytes et les transporteurs au glutamate représentent ainsi de potentielles cibles thérapeutiques dans le cadre des maladies neurodégénératives. L'étude de ces interactions neurones-astrocytes, en particulier sur des modèles in vivo, nécessite des outils particuliers permettant de disséquer le rôle de chaque type cellulaire. Cependant, il existe peu d'outils spécifiques et efficaces pour cibler les astrocytes in vivo. Notre objectif a été de développer un nouveau vecteur viral permettant une transduction spécifique des astrocytes in vivo, avec une efficacité importante et pouvant être utilisé dans l'ensemble du cerveau avec de nombreux transgènes. Au cours de ce travail nous avons développé trois voies de recherche. Ainsi, nous avons modifié l'enveloppe du vecteur et tester trois glycoprotéines d'enveloppe, VSV, Mokola et Rabies. Nous avons également utilisé trois promoteurs différents, PGK, CMV et EAAT1 afin de moduler l'expression du transgène dans les astrocytes. Et enfin, nous avons développé une nouvelle méthode de régulation post-transcriptionnelle utilisant les microARN. Nos résultats permettent de conclure qu'un vecteur lentiviral avec l'enveloppe Mokola, contenant le promoteur PGK et des cibles de microARN spécifiques des neurones est un outil efficace pour cibler les astrocytes in vivo. Nous avons utilisé ce nouvel outil pour surexprimer les transporteurs astrocytaires au glutamate (GLAST et GLT-1) et pour inhiber leur expression grâce aux techniques de « RNA silencing ». La surexpression du transporteur GLAST permet une neuroprotection significative en condition excitotoxique tandis que l'inhibition de GLT-1 induit une diminution du métabolisme cérébral. Ces résultats préliminaires apportent la preuve de principe de l'efficacité de notre outil in vivo et confirment le rôle central des transporteurs astrocytaires. Il est ainsi possible d'anticiper que ce nouvel outil permettra à la fois une meilleure compréhension du fonctionnement des astrocytes in vivo et qu'il peut représenter un vecteur de choix dans la perspective d'une thérapie génique ciblant ces cellules

Développement d un vecteur lentiviral ciblant les astrocytes in vivo et mise en application dans l étude des transporteurs au glutamate GLAST et GLT-1

Les astrocytes remplissent de nombreuses fonctions primordiales dans le cerveau notamment la modulation de la transmission synaptique et le couplage neurométabolique qui impliquent les transporteurs astrocytaires au glutamate GLAST et GLT-1. Leur étude est essentielle, cependant, il existe peu d outils permettant l étude de leur fonction in vivo. Notre objectif a été de développer un nouveau vecteur lentiviral permettant un transfert de gène uniquement dans les astrocytes in vivo. Nous avons développé trois voies de recherche : le changement de l enveloppe du vecteur, du promoteur et une nouvelle méthode de régulation post-transcriptionnelle utilisant les microARN. Nos résultats montrent que la combinaison de l enveloppe Mokola avec des cibles d un microRNA spécifiquement neuronal permet un ciblage astrocytaire spécifique et efficace. La surexpression du transporteur GLAST permet une neuroprotection significative en condition excitotoxique tandis que l inhibition de GLT-1 induit une diminution du métabolisme énergétique cérébral. La mise au point de ce nouvel outil permettra une meilleure compréhension du fonctionnement des astrocytes in vivo.PARIS-BIUSJ-Thèses (751052125) / SudocPARIS-BIUSJ-Physique recherche (751052113) / SudocSudocFranceF

Sjögren syndrome hidden by previous parotidectomy and cervicofacial radiotherapy

Introduction: Sjögren’s syndrome (SS) is a chronic inflammatory auto-immune disease of the exocrine glands which incidence increases with age. Sex ratio is 9.9 female for 1 male. Observation: A 67-year-old female patient presented for xerostomia leading to major functional impairment. The medical history of the patient was pulmonary sarcoidosis, with join and adenoid involvement, considered as cured; left partial parotidectomy, with a diagnosis of acinous carcinoma, followed 7 years later by a total parotidectomy due to tumor recurrence, and followed by external radiotherapy (70 Gy). Arterial hypertension, hypothyroïditis and diabetes mellitus were also noticed. She reported xerostomia and xerophtalmia. Seric anti-SSA antibodies were positive and histologic findings were compatible with SS. Commentaries: Despite other co-morbidities, the diagnosis was hidden by previous parotidectomy and cervical radiotherapy. Thus, SS should not be underdiagnosed in patients with complex medical history

Metabolic markers of protein maldigestion after a 15 N test meal in minipigs with pancreatic exocrine insufficiency

International audienceThe effect of pancreatic exocrine insufficiency (PEI) on protein malabsorption is little documented, partly due to methodological barriers. We aimed to validate biomarkers of protein malabsorption using a 15N test meal in a minipig model of PEI. Six pancreatic duct-ligated minipigs were used as a model of PEI and four nonoperated animals as a control. All animals were equipped with an ileocecal reentrant cannula. Minipigs were given a test meal containing [15N]casein. The PEI animals repeated the test three times, in the absence of any pancreatic enzymes, or after pancreatic substitution at two levels [A or B: 7,500 or 75,000 (lipase) and 388 or 3881 (protease) FIP U]. Ileal chyme, urine, and blood were collected postprandially. Nitrogen and 15N were measured in digestive and metabolic pools. We obtained a gradient of ileal protein digestibility from 29 ± 11% in PEI to 89 ± 6% in the controls and a dose- dependent response of enzymes. Insulin and gastric inhibitory polypeptide secretions were decreased by PEI, an effect that was counteracted with the enzymes at level B. The total recovery of 15N in urinary urea and plasma proteins was 14 ± 5.1% in the control group and decreased to 5.5 ± 2.1% by PEI. It was dose dependently restored by the treatment. Both 15N recovery in plasma and urine were correlated to protein digestibility. We confirm that the 15N transfer in those pools is a sensitive marker of protein malabsorption. Nevertheless, an optimization of the test meal conditions would be necessary in the view of implementing a clinical test.NEW & NOTEWORTHY We designed an intervention study to create a gradient of ileal protein digestibility in minipigs with pancreatic exocrine insufficiency and to validate reliable metabolic markers using a 15N oral meal test. 15N recovery in plasma proteins and to a higher extent in urine was sensitive to protein malabsorption. This test is minimally invasive and could be used to reveal protein malabsorption in patients