Evaluation of SU8 and ruthenium oxide materials for microfluidic devices

This thesis investigates two materials, SU8 photoresist and RuO₂, for possible incorporation into a self-calibrating microfluidic biosensor. The negative, epoxy based photoresist SU8 has been widely used in the fabrication of micro-electro-mechanical systems (MEMS) devices. This is due to its many desirable features that make it a suitable material for a wide variety of MEMS applications. The effects cross-linking (exposure dose) and bonding time have on bond strength and plasma modification of the SU8 surface were investigated as well as the bond strength of etched SU8. It was shown that adhesive bonding was an effective method of bonding, with bond strengths of 1500 psi possible. Plasma etching of SU8 was shown to significantly modify the surface while having a detrimental effect on bond strength. High oxygen plasma etching produced a hydrophilic SU8 surface, while CF₄ etching produced a hydrophobic surface. In both cases, the surface modification was shown to be temporary. Another important aspect of the biosensor is the electrode material. Ruthenium oxide (RuO₂) was examined because it has been shown to have much potential for use as an electrode. The resistivity, crystallinity and adhesion of reactively sputter deposited RuO₂ thin films to SU8 as a function of oxygen in the sputtering gas was investigated. It was found that both a change from Ru to RuO₂ films and a transition in preferred crystal orientation of RuO₂ in the films occurred as oxygen content in the film increased. It was shown that resistivity of RuO₂ is related to the amount of oxygen in the film. Film stress was shown to have a large impact on adhesion to SU8 and for this reason films produced in a moderate oxygen environment are suggested for use as an electrode material --Abstract, page iv

The Impact of Poor Health on Education: New Evidence Using Genetic Markers

This paper examines the influence of health conditions on academic performance during adolescence. To account for the endogeneity of health outcomes and their interactions with risky behaviors we exploit natural variation within a set of genetic markers across individuals. We present strong evidence that these genetic markers serve as valid instruments with good statistical properties for ADHD, depression and obesity. They help to reveal a new dynamism from poor health to lower academic achievement with substantial heterogeneity in their impacts across genders. Our investigation further exposes the considerable challenges in identifying health impacts due to the prevalence of comorbid health conditions and endogenous health behaviors.health, education, genetic predisposition, obesity, ADHD, depression, instrumental variables, risky health behaviors

The Impact of Poor Health on Education: New Evidence Using Genetic Markers

This paper examines the influence of health conditions on academic performance during adolescence. To account for the endogeneity of health outcomes and their interactions with risky behaviors we exploit natural variation within a set of genetic markers across individuals. We present strong evidence that these genetic markers serve as valid instruments with good statistical properties for ADHD, depression and obesity. They help to reveal a new dynamism from poor health to lower academic achievement with substantial heterogeneity in their impacts across genders. Our investigation further exposes the considerable challenges in identifying health impacts due to the prevalence of comorbid health conditions and endogenous health behaviors.

Bone Quality Changes In 3 Cases Of Hypophosphatasia: A Ftiri Study

International audienc

La Chambre des comptes de Bretagne au temps de la Fronde

Pendant la période de la Fronde, la Chambre des comptes de Bretagne est un exemple de fidélité au roi de France. Une étude du personnel de cette cour nous renseigne sur l’origine des officiers, leur renouvellement et la place de l’argent dans leur carrière. Ces magistrats, largement recrutés dans le monde des officiers bretons, continuent d’assurer avec régularité, pendant des années troublées, un triple rôle : ils enregistrent les décisions royales, ils rendent la justice dans tous les litiges financiers et, enfin, ils contrôlent les finances publiques.During the period of the Fronde, the Chambre des comptes of Brittany is an example of fidelity to the king of France. A study of the personnel of this court informs us about the origin of the officers, their renewal and the place of money in their career. These magistrates, largely borned of the world of the Breton officers, played with regularity, during these disturbed years, a triple role: they book the royal decisions, they do justice in all the financial litigations and, finally, they control the public finance

Centrifuge rolling test for ore liquefaction analysis

To study the development of liquefaction in ore cargo, a new Rolling Test has been designed to support similar stresses than those observed in a vessel. It can be used in an 80×g macrogravity field in the 5.5m radius Ifsttar geo-centrifuge. Its main characteristics are presented

Characterization of a Mycobacterium smegmatis uvrA mutant impaired in dormancy induced by hypoxia and low carbon concentration

<p>Abstract</p> <p>Background</p> <p>The aerobic fast-growing <it>Mycobacterium smegmatis</it>, like its slow-growing pathogenic counterpart Mycobacterium tuberculosis, has the ability to adapt to microaerobiosis by shifting from growth to a non-proliferating or dormant state. The molecular mechanism of dormancy is not fully understood and various hypotheses have been formulated to explain it. In this work, we open new insight in the knowledge of <it>M. smegmatis </it>dormancy, by identifying and characterizing genes involved in this behavior.</p> <p>Results</p> <p>In a library generated by transposon mutagenesis, we searched for <it>M. smegmatis </it>mutants unable to survive a coincident condition of hypoxia and low carbon content, two stress factors supposedly encountered in the host and inducing dormancy in tubercle bacilli. Two mutants were identified that mapped in the <it>uvrA </it>gene, coding for an essential component of the Nucleotide Excision Repair system (NER). The two mutants showed identical phenotypes, although the respective transposon insertions hit different regions of the <it>uvrA </it>gene. The restoration of the <it>uvrA </it>activity in <it>M. smegmatis </it>by complementation with the <it>uvrA </it>gene of <it>M. tuberculosis</it>, confirmed that i) <it>uvrA </it>inactivation was indeed responsible for the inability of <it>M. smegmatis </it>cells to enter or exit dormancy and, therefore, survive hypoxia and presence of low carbon and ii) showed that the respective <it>uvrA </it>genes of <it>M. tuberculosis </it>and <it>M. smegmatis </it>are true orthologs. The rate of survival of wild type, <it>uvrA </it>mutant and complemented strains under conditions of oxidative stress and UV irradiation was determined qualitatively and quantitatively.</p> <p>Conclusions</p> <p>Taken together our results confirm that the mycobacterial NER system is involved in adaptation to various stress conditions and suggest that cells with a compromised DNA repair system have an impaired dormancy behavior.</p

Management of Esophageal Carcinoma Associated with Cirrhosis: A Retrospective Case-Control Analysis

Objectives. Esophageal carcinoma and cirrhosis have the overlapping etiologic factors. Methods. In a retrospective analysis conducted in 2 Breton institutions we wanted to asses the frequency of this association and the outcome of these patients in a case-control study where each case (cirrhosis and esophageal cancer) was paired with two controls (esophageal cancer). Results. In a 10-year period, we have treated 958 esophageal cancer patients; 26 (2.7%) had a cirrhosis. The same treatments were proposed to the 2 groups; cases received nonsignificantly different radiation and chemotherapy dose than controls. Severe toxicities and deaths were more frequent among the cases. At the end of the treatment 58% of the cases and 67% of the controls were in complete remission; median and 2-year survival were not different between the 2 groups. All 4 Child-Pugh B class patients experienced severe side effects and 2 died during the treatment. Conclusions. This association is surprisingly infrequent in our population! Child-Pugh B patients had a dismal prognosis and a bad tolerance to radiochemotherapy; Child-Pugh A patients have the same tolerance and the same prognosis as controls and the evidence of a well-compensated cirrhosis has not modified our medical options