HIGH SPIN ISOMERIC STATES IN 197Pb

High spin isomeric states in 197Pb have been investigated by in-beam gamma ray technics. These states are produced in (heavy ion, xn) reactions. various experiments performed are summarized in table I

FACTEUR GYROMAGNÉTIQUE DE L'ÉTAT 12+ DES ISOTOPES DE PLOMB DE MASSE 198, 196 ET 194

Un état isomérique 12+, interprété comme un état à deux quasi-particules (νi 13/2)-2, a été mis en évidence dans les isotopes de plomb déficients en neutrons. Il possède une période de quelques centaines de ns, qui se prête à la mesure du moment magnétique par la méthode des distributions angulaires différentielles perturbées (TDPAD). Ces mesures ont été réalisées, afin de confirmer la configuration de l'état et d'étudier l'effet du nombre de nucléons sur les phénomènes de polarisation du coeur. Le tableau indique les valeurs expérimentales du facteur g et de la période du niveau 12+ des isotopes de masse A = 198, 196, 194. Une analyse multidimensionnelle des informations (Eγ, t) permet d'étudier simultanément ces trois noyaux, formés par la réaction naturelle W(16O, 4n)Pb. Les facteurs g sont reportés sur la figure, ainsi que les valeurs obtenues par ailleurs pour l'état 12+ du 206Pb [1], 200Pb [2] et l'état 13+/2 du 205Pb [3]. [MATH]. La constance de g en fonction de A suggère que les effets observés dans le 206Pb se retrouvent dans les isotopes plus légers, et notamment que la configuration (νi 13/2)-2 demeure largement dominante. L'écart notable à la valeur de Schmidt (g = - 0,294) peut s'expliquer par un important effet de polarisation du coeur. Un calcul, utilisant le formalisme de Arima et Horie, et une interaction résiduelle delta de surface (SDI) sont effectués pour rendre compte de ces résultats

Onecut-dependent Nkx6.2 transcription factor expression is required for proper formation and activity of spinal locomotor circuits.

In the developing spinal cord, Onecut transcription factors control the diversification of motor neurons into distinct neuronal subsets by ensuring the maintenance of Isl1 expression during differentiation. However, other genes downstream of the Onecut proteins and involved in motor neuron diversification have remained unidentified. In the present study, we generated conditional mutant embryos carrying specific inactivation of Onecut genes in the developing motor neurons, performed RNA-sequencing to identify factors downstream of Onecut proteins in this neuron population, and employed additional transgenic mouse models to assess the role of one specific Onecut-downstream target, the transcription factor Nkx6.2. Nkx6.2 expression was up-regulated in Onecut-deficient motor neurons, but strongly downregulated in Onecut-deficient V2a interneurons, indicating an opposite regulation of Nkx6.2 by Onecut factors in distinct spinal neuron populations. Nkx6.2-null embryos, neonates and adult mice exhibited alterations of locomotor pattern and spinal locomotor network activity, likely resulting from defective survival of a subset of limb-innervating motor neurons and abnormal migration of V2a interneurons. Taken together, our results indicate that Nkx6.2 regulates the development of spinal neuronal populations and the formation of the spinal locomotor circuits downstream of the Onecut transcription factors

A gene expression atlas of the domestic pig

<p>Abstract</p> <p>Background</p> <p>This work describes the first genome-wide analysis of the transcriptional landscape of the pig. A new porcine Affymetrix expression array was designed in order to provide comprehensive coverage of the known pig transcriptome. The new array was used to generate a genome-wide expression atlas of pig tissues derived from 62 tissue/cell types. These data were subjected to network correlation analysis and clustering.</p> <p>Results</p> <p>The analysis presented here provides a detailed functional clustering of the pig transcriptome where transcripts are grouped according to their expression pattern, so one can infer the function of an uncharacterized gene from the company it keeps and the locations in which it is expressed. We describe the overall transcriptional signatures present in the tissue atlas, where possible assigning those signatures to specific cell populations or pathways. In particular, we discuss the expression signatures associated with the gastrointestinal tract, an organ that was sampled at 15 sites along its length and whose biology in the pig is similar to human. We identify sets of genes that define specialized cellular compartments and region-specific digestive functions. Finally, we performed a network analysis of the transcription factors expressed in the gastrointestinal tract and demonstrate how they sub-divide into functional groups that may control cellular gastrointestinal development.</p> <p>Conclusions</p> <p>As an important livestock animal with a physiology that is more similar than mouse to man, we provide a major new resource for understanding gene expression with respect to the known physiology of mammalian tissues and cells. The data and analyses are available on the websites <url>http://biogps.org and http://www.macrophages.com/pig-atlas</url>.</p

NIVEAUX COLLECTIFS ET INTRINSÈQUES DE 170Lu

Le schéma de niveau du noyau impair-impair 170Lu a été étudié à partir de la désintégration par capture électronique de 170Hf. Ce dernier est formé par réaction (p, 6n) sur des cibles d'oxyde de lutécium. L'isotope 170Hf est alors séparé des autres isotopes à l'aide du séparateur isotopique du Laboratoire Joliot-Curie (Orsay). Des mesures de spectres γ, d'électrons de conversion, des coïncidences ßγ et γ ont permis de proposer un schéma de niveau pour 170Lu. Celui-ci présente comme caractéristiques une bande de rotation inversée, une transition isomérique d'interdiction K et de nombreux niveaux intrinsèques dont certains sont interprétables à l'aide du modèle de Nilsson et des règles de couplage de Gallagher-Moszkowski.The level scheme of the 170Lu odd-odd nucleus has been studied from the decay of 170Hf by electron capture. 170Hf is produced by means of a (p, 6n) reaction on a Lu2O3 target and selected by the mass separator of the Joliot-Curie laboratory (Orsay). Conversion electrons and γ spectra, ßγ and γ-γ coincidence measurements lead us to a level scheme for 170Lu. The characteristics of this level scheme are, besides an inverted rotational band, an isomeric K- forbidden transition and various single-particle levels some of which can be explained by Nilsson's model joined to Gallagher-Moszkowski coupling rules

Niveau isomérique de 122Sb

Pas de Résumé disponibl

Production of O-14, O-15, F-18, and Ne-19 radioactive nuclei from (p, n) reactions up to 30 MeV

Total cross sections for proton-induced reactions on N14,15, O18, and F19 targets were measured by the activation method, up to 30 MeV. Yields of nuclei of astrophysical interest, i.e. O14,15, F18, Ne19 were obtained. © 1990 The American Physical Society.SCOPUS: ar.jinfo:eu-repo/semantics/publishe