3D-printed system optimizing dissolution of hyperpolarized gaseous species for micro-sized NMR

International audienceDissolution of hyperpolarized species in liquids of interest for NMR is often hampered by the presence of bubbles that degrade the field homogeneity. Here a device constituted by a bubble pump and a miniaturized NMR cell fitting both inside the narrow bore of an NMR magnet is built by 3D printing. 129Xe NMR experiments performed with hyperpolarized xenon reveal high and homogeneous dissolution of the gas in water

Measurement and determinants of health poverty and richness: evidence from Portugal

The analysis of health inequalities is a critical topic for health policy. With data for Portugal, we propose a procedure to convert information provided by the official National Health Survey to EuroQol. Based on these data, we make two contributions. First, we extend measures and methods commonly applied in other fields of economic research in order to quantify the phenomena of health poverty, richness, and inequality. Second, using an ordered probit model, we evaluate the determinants of health inequalities in Portugal. The results show that there is a remarkable level of health inequality, with significant rates of poverty (11.64%) and richness (22.64%). The econometric study reveals that gender, age, education, region of residence, and eating habits are among the most critical determinant factors of health

Comparison of distribution and activity of nanoparticles with short interfering DNA (Dbait) in various living systems

Introducing small DNA molecules (Dbait) impairs the repair of damaged chromosomes and provides a new method for enhancing the efficiency of radiotherapy in radio-resistant tumors. The radiosensitizing activity is dependent upon the efficient delivery of Dbait molecules into the tumor cells. Different strategies have been compared, to improve this key step. We developed a pipeline of assays to select the most efficient nanoparticles and administration protocols before preclinical assays: (i) molecular analyses of complexes formed with Dbait molecules, (ii) cellular tests for Dbait uptake and activity, (iii) live zebrafish embryo confocal microscopy monitoring for in vivo distribution and biological activity of the nanoparticles and (iv) tumor growth and survival measurement on mice with xenografted tumors. Two classes of nanoparticles were compared, polycationic polymers with linear or branched polyethylenimine (PEI) and covalently attached cholesterol (coDbait). The most efficient Dbait transfection was observed with linear PEI complexes, in vitro and in vivo. Doses of coDbait ten-fold higher than PEI/Dbait nanoparticles, and pretreatment with chloroquine, were required to obtain the same antitumoral effect on xenografted melanoma. However, with a 22-fold lower ‘efficacy dose/toxicity dose' ratio as compared with Dbait/PEI, coDbait was selected for clinical trials

Atrophy of primary lymphoid organs induced by Marek's disease virus during early infection is associated with increased apoptosis, inhibition of cell proliferation and a severe B-lymphopenia

Marek's disease is a multi-faceted highly contagious disease affecting chickens caused by the Marek's disease alphaherpesvirus (MDV). MDV early infection induces a transient immunosuppression, which is associated with thymus and bursa of Fabricius atrophy. Little is known about the cellular processes involved in primary lymphoid organ atrophy. Here, by in situ TUNEL assay, we demonstrate that MDV infection results in a high level of apoptosis in the thymus and bursa of Fabricius, which is concomitant to the MDV lytic cycle. Interestingly, we observed that in the thymus most of the MDV infected cells at 6 days post-infection (dpi) were apoptotic, whereas in the bursa of Fabricius most of the apoptotic cells were uninfected suggesting that MDV triggers apoptosis by two different modes in these two primary lymphoid organs. In addition, a high decrease of cell proliferation was observed from 6 to 14 dpi in the bursa of Fabricius follicles, and not in the thymus. Finally, with an adapted absolute blood lymphocyte count, we demonstrate a major B-lymphopenia during the two 1st weeks of infection, and propose this method as a potent non-invasive tool to diagnose MDV bursa of Fabricius infection and atrophy. Our results demonstrate that the thymus and bursa of Fabricius atrophies are related to different cell mechanisms, with different temporalities, that affect infected and uninfected cells

E. P. R. STUDIES OF LITTLE PARTICLES OF LITHIUM CREATED BY γ IRRADIATION IN HLi

Nous avons déterminé expérimentalement que les petites particules de lithium créées par irradiation γ dans le HLi produisent une raie de résonance paramagnétique électronique inhomogène. Pour expliquer ce phénomène nous avons élaboré un modèle dans lequel la largeur de raie de R.P.E. est déterminée par la dispersion du moment magnétique nucléaire total du précipité. En supposant que les tailles des précipités obéissent à une loi de distribution gaussologarithmique, nous déterminons par une méthode de moindres carrés les différents paramètres de la distribution, l'un d'entre eux pouvant être assimilé à une taille moyenne de précipités. Nous donnons l'évolution de la distribution des tailles de colloïdes créés dans le HLi irradié à différentes doses de rayonnement γ et à différentes températures. L'évolution de la distribution des tailles des particules présentes dans des échantillons recuits à des températures différentes durant des temps déterminés a été étudiée. Nous constatons que de nombreuses petites particules sont créées tandis que les grosses disparaissent. Pour les hautes températures de recuit la distribution des tailles ne reste pas gaussologarithmique.We show that little particles of lithium created by γ irradiation in HLi give an inhomogeneous E.P.R. line. A model is made to explain this result : we point out that E. P. R. line width is induced by the dispersion of the total magnetic moment inside the small particle. Assuming that the size distribution of precipitates is a logarithmiconormal distribution, with the help of a method of least squares we determine the various parameters of the distribution, one of them can be compared with the mean size of the precipitates. The evolution of the sizes distribution of lithium colloids created in HLi irradiated with different γ doses and at different temperatures are given. We have studied the evolution of the size distribution of particles in samples annealed with different temperatures and times. We can see that many little particles are created while large colloids vanish. When the temperature of annealing is very high the sizes distribution does not remain a logarithmiconormal distribution

A TECHNIQUE FOR EQUATION STATE DETERMINATION OF LIQUID METALS AT HIGH TEMPERATURES AND PRESSURES

L'appareillage qui est décrit permet des mesures thermophysiques sur des métaux soumis à des pressions allant jusqu'à 0,6 GPa et des températures comprises entre 1500 et 8000°K. L'échantillon métallique est contenu dans une enceinte remplie d'argon gazeux sous haute pression et est chauffé par effet joule à l'aide de la décharge d'un banc de condensateurs. Durant l'expérience, des mesures du courant, de la tension entre deux points du fil, de la température et de la variation de diamètre du fil, sont effectuées.An apparatus for making thermophysical measurements on metal at pressures up to 0.6 GPa and in the temperature range from 1500 to 8000°K is described. A metallic sample standing in an argon-filled-vesse1 is resistively heated by decharging a capacitor bank through it. During an experimental shot, current, voltage drop across two parts of the wire, diameter and temperature are measured

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Notions sur le service d'expériences sur l'entretien des routes, et particulièrement sur son origine, sur les principaux faits et principes qui en légitiment l'existence ou ont avec lui des rapports intimes, sur son état présent et su les résultats auxquels il est déja parvenu

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Perméabilité intrinsèque et extrinsèque de couches minces ferromagnétiques et de multicouches ferromagnétique-isolant en fonction de la fréquence : comparaison expérience - modèle

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