Hysteretic characteristics of a double stripline in the critical state

Analytical investigations of the critical state are carried out for a superconducting stripline consisting of two individual coplanar strips with an arbitrary distance between them. Two different cases are considered: a stripline with transport current and strips exposed to a perpendicular magnetic field. In the second case, the obtained solutions correspond to "fieldlike" (for unclosed strips) and "currentlike" (for a long rectangular superconducting loop) states in an isolated strip to which both a transport current and a magnetic field are applied with constant ratio.Comment: 8 pages, 6 figures. accepted by SS

Continuous flow micro-cell for electrochemical addressing of engineered bio-molecules

Abstract A micro-cell consisting of a planar array of Au working electrodes, covered by a glass reservoir (600 nl capacity), connected with perpendicular capillaries and provided with an Ag/AgCl wire reference electrode (RE) has been manufactured. Addressed on-chip immobilization and sensing of biomolecules was demonstrated by the immobilization of histidine (HIS) tagged alkaline phosphatase (AP) under continuous flow (10 l/min) conditions on the base of electrochemically deposited multilayer (EDM) of cysteamine modified by nitrilotriacetic acid (NTA). The presented method allows the immobilization of different biomolecules on the ready-to-use reservoir covered chip without needs of manual biomolecule deposition. Further on, the detection of analytes can be performed using the electrochemical measurements. Since the methods of biomolecule deposition and sensing are both electrochemical, this allows simplifying the production technology using cheaper detection instruments compared to prevailing present-day optical detection modes

Drosophila Histone Deacetylase-3 Controls Imaginal Disc Size through Suppression of Apoptosis

Histone deacetylases (HDACs) execute biological regulation through post-translational modification of chromatin and other cellular substrates. In humans, there are eleven HDACs, organized into three distinct subfamilies. This large number of HDACs raises questions about functional overlap and division of labor among paralogs. In vivo roles are simpler to address in Drosophila, where there are only five HDAC family members and only two are implicated in transcriptional control. Of these two, HDAC1 has been characterized genetically, but its most closely related paralog, HDAC3, has not. Here we describe the isolation and phenotypic characterization of hdac3 mutations. We find that both hdac3 and hdac1 mutations are dominant suppressors of position effect variegation, suggesting functional overlap in heterochromatin regulation. However, all five hdac3 loss-of-function alleles are recessive lethal during larval/pupal stages, indicating that HDAC3 is essential on its own for Drosophila development. The mutant larvae display small imaginal discs, which result from abnormally elevated levels of apoptosis. This cell death occurs as a cell-autonomous response to HDAC3 loss and is accompanied by increased expression of the pro-apoptotic gene, hid. In contrast, although HDAC1 mutants also display small imaginal discs, this appears to result from reduced proliferation rather than from elevated apoptosis. The connection between HDAC loss and apoptosis is important since HDAC inhibitors show anticancer activities in animal models through mechanisms involving apoptotic induction. However, the specific HDACs implicated in tumor cell killing have not been identified. Our results indicate that protein deacetylation by HDAC3 plays a key role in suppression of apoptosis in Drosophila imaginal tissue

Analyse de clusters et classification chimiométrique des eaux au sud de Paris

Le but de ce travail consiste à proposer des modèles de classification multivariés pour le contrôle analytique d’un nombre élevé de sources d’eau situé au sud-est de Paris. Ces modèles sont susceptibles d’effectuer une évaluation globale des échantillons par compulsion simultanée d’un grand nombre de paramètres analytiques et ils représentent ensuite un outil valide pour une télésurveillance continue des eaux. Pour la construction des modèles, deux méthodes chimiométriques très avancées ont été utilisées : Analyse de Clusters et Classification, par recours à des logiciels de dernière génération. L’ensemble des objets est composé de 69 points de prélèvement, chacun décrit par 9 paramètres analytiques sélectionnés, concernant des analyses effectuées durant l’année 2004. Dans une première phase on a effectué la distribution des sources en cluster en appliquant à la matrice de données, l’algorithme de type agglomérative hiérarchique Average Linkage, en utilisant comme discriminant le calcul de la Distance Euclidienne entre les objets. Pour l’examen de la similarité, 4 clusters ont été définis, chacun composé par un nombre variable de sources. En ce qui concerne la matrice de données dans laquelle les clusters représentent la variable dépendante, on a appliqué l’algorithme de régression PLS1 (Partial Least Squares) pour la construction d’un modèle multivarié. Le modèle obtenu a donc été soumis aux « procès » d’optimisation et de validation. Le modèle final a été ainsi appliqué à une nouvelle matrice de données, concernant les analyses effectuées en 2005 sur des échantillons analogues, pour apprécier les variations éventuelles dans la Classification des sources considérées. Il a été possible de souligner que la plus grande partie des points de prélèvement, dans le laps de temps d’une année, s’est placée à l’intérieur des clusters d’origine, à l’exception de 8 sources qui ont été classées dans un autre Cluster à la suite de variations statistiquement significatives de quelques paramètres analytiques

High plasticity reversible resistive switching in heteroepitaxial metal/CeO 2− x

We report on the characterization of resistive switching devices based on epitaxial CeO2 thin films as a functional material. CeO2 epitaxial thin films were grown by the pulsed laser deposition technique on conductive substrates. Platinum and titanium nitride top electrodes (TE) were successively deposited. Very good performances, in terms of resistivity switching and multilevel operation capability, were obtained using the Pt TE. The dependence of the low resistance and high resistance state on the TE material and on the CeO2 film thickness were explained. The electrical characteristics of these heterostructures make them promising as synapse for neuromorphic computation, but suggest also their use with multi-valued digital systems or multibit memory cells

Evolution of the magnetic structure with chemical composition in spinel iron oxide nanoparticles

Magnetic properties of iron oxide nanoparticles with spinel structure are strictly related to a complex interplay between cationic distribution and the presence of a non-collinear spin structure (spin canting). With the aim to gain better insight into the effect of the magnetic structure on magnetic properties, in this paper we investigated a family of small crystalline ferrite nanoparticles of the formula CoxNi1-xFe2O4 (0 64 x 64 1) having equal size ( 484.5 nm) and spherical-like shape. The field dependence of magnetization at low temperatures indicated a clear increase of magnetocrystalline anisotropy and saturation magnetization (higher than the bulk value for CoFe2O4: 3c130 A m2 kg-1) with the increase of cobalt content. The magnetic structure of nanoparticles has been investigated by M\uf6ssbauer spectroscopy under an intense magnetic field (8 T) at a low temperature (10 K). The magnetic properties have been explained in terms of an evolution of the magnetic structure with the increase of cobalt content. In addition a direct correlation between cationic distribution and spin canting has been proposed, explaining the presence of a noncollinear spin structure in terms of superexchange interaction energy produced by the average cationic distribution and vacancies in the spinel structure