L’étape de dissolution des combustibles nucléaires usés, réalisée en milieu nitrique concentré, est complexe notamment du fait de leur complexité chimique et microstructurale à l’issue de leur passage en réacteur. Ainsi, la présence de produits de fission (PF) localisés au sein des différentes phases cristallines constitutives du combustible usé peut en impacter la vitesse de dissolution. Dans ce cadre, trois systèmes représentatifs du matériau combustible initial UO2, de UO2 contenant des PF dissous au sein de la phase fluorine ou formant de précipités métalliques ont été obtenus par conversion de précurseurs préparés par voie humide (oxalate, hydroxyde). Pour chaque système, des pastilles denses et de microstructures proches de celle retrouvée au sein du combustible usé ont été préparées à l’issue d’une étape de mise en forme suivie d’un traitement thermique à haute température.L’étude multiparamétrique de la dissolution (approche macroscopique) conduite dans plusieurs solutions d’acide nitrique et à diverses températures a souligné l’impact important joué par la composition chimique sur la durabilité chimique des échantillons. Ainsi, l’incorporation d’éléments lanthanide a conduit à une augmentation de la vitesse de dissolution par rapport à l’échantillon UO2 de référence, laquelle est demeurée largement inférieure à celle relevée en présence d’éléments platinoïde. Par ailleurs, les effets de l’acidité et de la température du milieu sur la vitesse de dissolution ont été examinés et des modifications significatives dans le mécanisme de dissolution prépondérant ont été suggérées pour des concentrations d’acide nitrique supérieures à 0,5 mol.L-1.Pour les trois systèmes sélectionnés, l’évolution de l’interface solide/solution a également été suivie en cours de dissolution à travers une étude operando, réalisée par Microscopie Electronique à Balayage en mode Environnemental (approche microscopique). En présence d’éléments lanthanide ou à proximité des éléments platinoïde métalliques, ce suivi a démontré l’existence de zones de dissolution préférentielles dont les joints de grains et les jonctions triples. Le couplage des résultats obtenus à travers ces deux approches a permis de fournir des données complémentaires en vue d’une meilleure compréhension des mécanismes de dissolution mis en jeu en présence des différents PF considérés. / The dissolution of spent nuclear fuels, performed in concentrated nitric acid solution, is a complex process due to some chemical and microstructural heterogeneities. As instance, the presence of Fission Products (FP) in various phases constitutive of spent nuclear fuels can affect the chemical durability of the materials. In this context, three systems of interest representing fresh UO2 used as reference material, and UO2 doped with FP products dissolved in the fluorite structure (lanthanide elements) or incorporated as metallic precipitates (platinoids) were prepared by oxalic or hydroxide precipitation. Dense pellets with microstructure representative for spent nuclear fuel were prepared through sintering step at high temperature.The multiparametric study of the dissolution (macroscopic approach) was developed by varying independently several parameters. While incorporation of lanthanide elements induced a significant increase of the normalized dissolution rates, it remained lower compared to that observed for platinoids. Moreover, increase of nitric acid concentration or temperature led to the decrease of the chemical durability of the prepared materials. Additionally, significant modification of the preponderant mechanism of dissolution occurred for nitric acid concentration higher than 0.5 mol.L-1.For the three selected systems, the monitoring of the evolving solid/solution interface (microscopic approach) was performed operando by Environmental Scanning Electron Microscopy. Compared to pure UO2, the presence of FP (lanthanide elements or metallic platinoids) induced preferential dissolution of grain boundaries and triple junctions. Coupling the results obtained from micro- and macroscopic approaches led to complementary data of strong interest in order to improve the understanding of the role of FP during the dissolution of UO2.

This thesis first briefly mentions the characteristics of the skin and contains a review of current knowledge on the in vitro permeation testing of drugs through the skin. It describes the basic data about nerve agents and the possibilities of prophylaxis poisoning warfare agents focusing on preventive transdermal administration. The experimental work is focused on in vitro testing abilities oxime HI-6 and posibly other reactivators enzyme acetylcholinesterase penetrate through pig skin. Experiments were conducted in static diffusion cells Franz type. The amount of test substance leaked through the skin is determined in the sample of receptor fluid by HPLC. Keywords permeation in vitro; transdermal; pig skin; Franz cell; substance HI-6; antidota; nerve agents; acetylcholinesterase

Background: Maternal stress during utero has been shown to have negative health consequences on the offspring, including low birth weight and increased risk of adult disease. Variation in breastmilk may act as an environmental cue of maternal stress and continue to program the infant during early life. This research aimed to explore the role of breastmilk on developmental programming of the infant. Specifically, to examine how breastmilk may act as a medium for the exposure of stress between the mother and the offspring, and see if variation in insulin like growth factor-1 (IGF-1) a potential mechanism for the relationship. Methods: Survey-interviews, anthropometrics of the mother and offspring (height and weight), and breastmilk samples were collected for 31 breastfeeding mother-offspring pairs in the Tampa Bay area. Breastmilk was analyzed for IGF-1 and fat content. Maternal stress was measured through the PSS-10 and two self-reported ten-point stress scales. Offspring length for age and weight for age Z-scores were calculated using LMS equation. Results: PPS-10 score was negatively correlated with child length for age and weight for age Z-scores. Child length for age and weight for age Z-scores were also negatively correlated with the breastmilk fat variables (creamatocrit percent, fat g/dL, and kcal/dL). No relationships were found between breastmilk IGF-1 and offspring length for age, weight for age, or maternal stress. Conclusions: Results indicate that maternal stress may negatively impact offspring growth. However, more research is necessary to better understand if or how breastmilk fat may act as a mechanism to mediate offspring growth due to maternal stress. This sample had low levels and prevalence of detectable IGF-1, which likely contributed to the lack of statistical relationships. Further research using lower dilutions and larger samples sizes is necessary to better explore the potential role of breastmilk IGF-1 on offspring growth and/or its relationship to maternal stress.

Goal of master thesis Specifics of Quantitave Easing of ECB and exit strategy is to analyse monetary policy called Quantitative easing and its exit strategy. Largest part of thesis addresses this monetary policy on example of European central bank but there is also summary transmission mechanisms and opinions of effectivness of this monetary policy on examples of other central banks. On example of ECB this work describes process of quantitative easing. Also there is empicital analysis of impacts of purchases under Securities market programme on yields of goverment bonds. Result of this anylsis is finding that SMP was effective only partly, mainly at time of its announcement. Further the work analysis current balance sheet of ECB from the perspective of exit from quantitative easing concluding that ECB would be able to execute exit strategy to these days.