Composite cathode based on yttria stabilized bismuth oxide for low-temperature solid oxide fuel cells

The investigation of composite cathodes consisting of silver and yttria stabilized bismuth oxide (YSB) for low-temperature honeycomb solid oxide fuel cells with stabilized zirconia as electrolyte was presented. The interfacial polarization resistances of a porous YSN-Ag cathode was about 0.3 ?? cm 2 at 600?? C. It was found by impedance analysis that the performance of an YSB-Ag composite cathode fired at 850?? C for 2 H was severely limited by gas transport due to insufficient porosity.open464

Electrodeposition on Nanofibrous Polymer Scaffolds: Rapid Mineralization, Tunable Calcium Phosphate Composition and Topography

A straightforward, fast and versatile technique to fabricate mineralized nanofibrous polymer scaffolds for bone regeneration is developed. Nanofibrous poly( L -lactic acid) scaffolds are fabricated using both electrospinning and phase separation techniques. An electrodeposition process is designed to deposit calcium phosphate on the nanofibrous scaffolds. Such scaffolds contain a high quality mineral coating on the fiber surface and have surface topography and chemical composition that are tunable by varying the processing parameters. These scaffolds can mimic the composition and structure of the natural bone extracellular matrix and provide a more biocompatible interface for bone regeneration.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/78221/1/adfm_201000993_sm_supplfigs.pd

Genome-wide mapping reveals conserved and diverged R-loop activities in the unusual genetic landscape of the African trypanosome genome

R-loops are stable RNA–DNA hybrids that have been implicated in transcription initiation and termination, as well as in telomere maintenance, chromatin formation, and genome replication and instability. RNA Polymerase (Pol) II transcription in the protozoan parasite Trypanosoma brucei is highly unusual: virtually all genes are co-transcribed from multigene transcription units, with mRNAs generated by linked trans-splicing and polyadenylation, and transcription initiation sites display no conserved promoter motifs. Here, we describe the genome-wide distribution of R-loops in wild type mammal-infective T. brucei and in mutants lacking RNase H1, revealing both conserved and diverged functions. Conserved localization was found at centromeres, rRNA genes and retrotransposon-associated genes. RNA Pol II transcription initiation sites also displayed R-loops, suggesting a broadly conserved role despite the lack of promoter conservation or transcription initiation regulation. However, the most abundant sites of R-loop enrichment were within the regions between coding sequences of the multigene transcription units, where the hybrids coincide with sites of polyadenylation and nucleosome-depletion. Thus, instead of functioning in transcription termination the most widespread localization of R-loops in T. brucei suggests a novel correlation with pre-mRNA processing. Finally, we find little evidence for correlation between R-loop localization and mapped sites of DNA replication initiation

Genome-Wide Analysis of Translation in the Early Drosophila Embryo

Regulation of translation plays an essential role in Drosophila embryogenesis, as loss or misexpression of regulatory proteins can cause lethal development defects. As a result of its importance in these early developmental events, there has been considerable study of translation in the early embryo. Here, I complement those studies with an investigation into translation on a genome-wide scale. In chapter 2, I describe my development and optimization of polysome-gradient protocols to study translation in the mature oocyte and early embryo on a genome-wide scale. In chapter 3, I combine the protocols developed in chapter 2 with microarray analysis to study the role of Smaug, a sequence specific RNA-binding protein, in regulating translation on a genome-wide scale. Comparisons of the list of mRNAs that co-immunoprecipitate with Smaug with those that are translationally repressed by Smaug and those that are degraded by Smaug, suggests that Smaug directly regulates the translation and stability of a large number of mRNAs in the early embryo. I also developed a new algorithm to search for Smaug binding sites, which are called Smaug Recognition Elements (SREs), in mRNAs. The presence of SREs was shown to predict Smaug binding and translational regulation. Taken together these data indicate that Smaug plays a direct and global role in regulating the translation and stability of a large fraction of the mRNAs in the early Drosophila embryo.Ph

Contribution à la microanalyse X des revêtements superficiels. Application aux biomatériaux

L objet de l étude concerne la caractérisation physico-chimique des revêtements superficiels par microanalyse x et son application a l étude des revêtements prothétiques phosphocalciques. Nous avons étudies les mécanismes de formation des phosphates de calcium par electrodeposition. Nous avons vérifie les hypothèses avancées par une étude portant sur l influence de la densité de courant sur les phosphates de calcium électrodéposés. Pour caractériser ces revêtements, nous avons développé une méthodologie en microanalyse x basée sur la complémentarité de la microscopie électronique a balayage et de la microscopie électronique a balayage transmission. Par la suite, nous nous sommes intéressés aux cartographies quantitatives des films minces sur substrats. Nous avons illustre l impact de l hétérogénéité du substrat sur la quantification des films minces ; puis, nous avons présente TF_Quantif, l algorithme de quantification (concentrations et épaisseurs) que nous préconisons pour s affranchir de ces problèmes. Nous avons aussi mené une étude théorique pour déterminer les limites d application de TF_Quantif. Enfin, nous avons présenté les développements logiciels et instrumentaux nécessaires a l utilisation de TF_Quantif et nous avons effectue des profils et cartographies quantitatifs sur des films minces (de composition et d épaisseur connue) sur substrats hétérogènes ainsi que sur un revêtement de phosphate de calcium. Les résultats ont été compares avec ceux obtenus par un logiciel de quantification que nous avons développé a partir du logiciel commercial STRATAGem (SAMx, France).This work deals with electron probe microanalysis of thin films and its application to thickness and concentration determination in the case of prosthetic calcium phosphate coatings. In a first part, we have studied the formation mechanisms of calcium phosphate elaborated by electrodeposition. We carried out a methodology based on the complementarities of scanning electron microscopy and scanning transmission microscopy both associated to x-ray microanalysis. This method allowed us to verify our hypothesis about calcium phosphate formation and showed that the current density is directly connected to the kind of electrodeposited calcium phosphate. In a second part, we have carried out quantitative elemental mapping of thin film on heterogeneous substrate. Through different examples, we showed that substrate heterogeneity has a direct influence on the thin film quantification. We developed a new quantification algorithm called tf_quantif which allows us removing substrate effects during the analysis associated to a theoretical approach which determine the thickness limit of this method. Moreover, we presented the quantification software and experimental setup developed in order to use tf_quantif . Finally, we applied tf_quantif on quantitive profiles and maps on several kinds of thin films on heterogeneous substrate (including electrodeposited calcium phosphate coatings). The results were compared to those obtained from commercial software (stratagem, samx, france). We showed that our quantification algorithm gave better results in the case of thickness determination and could be successfully applied in the case of quantitative maps of thin film on heterogeneous substrate.REIMS-BU Sciences (514542101) / SudocSudocFranceF

The Effect of Russian Colonialism on Ukrainian cultural identity

Since 2014, Russian aggression in Ukraine has exponentially increased, culminating in a war between the two nations. As Russian influences and colonial practices continue to dominate Ukraine, Ukrainian identity has come into question. As a nation, Ukraine, now more than ever, has been fighting to show its own cultural identity separate from Russia. However, one cannot downplay the impact Russian colonialist practices have had on Ukrainian identity and how influences it. We can better understand how this has affected Ukrainian identity by examining Russian-rooted corruption, food perception, and propaganda directed at Ukraine. This research aims to answer how Russian colonialist practices such as corruption, food control/perception, and propaganda have shaped Ukrainian cultural identity.        Faculty Mentor: Dr. Michael Gulayets&nbsp