Etude de la zone de transport des solides dans une extrudeuse monovis

Description générale de l'extrudeuse -- Les zones d'extrusion et leurs rôles -- Problèmes associés à la zone de transport des solides -- Modèles décrivant la zone de transport des solides -- Révision des travaux portant sur le coefficient de friction -- Propriétés physiques -- Matériaux -- La conductivité thermique -- Densité du polymère -- Rhéologie -- Module d'Young -- Essais de compaction -- Coefficients de friction -- Modélisation -- Zone de transport des solides -- Zone de retard de la fusion -- Méthode de résolution

Structure-Function Model for Kissing Loop Interactions That Initiate Dimerization of Ty1 RNA

The genomic RNA of the retrotransposon Ty1 is packaged as a dimer into virus-like particles. The 5′ terminus of Ty1 RNA harbors cis-acting sequences required for translation initiation, packaging and initiation of reverse transcription (TIPIRT). To identify RNA motifs involved in dimerization and packaging, a structural model of the TIPIRT domain in vitro was developed from single-nucleotide resolution RNA structural data. In general agreement with previous models, the first 326 nucleotides of Ty1 RNA form a pseudoknot with a 7-bp stem (S1), a 1-nucleotide interhelical loop and an 8-bp stem (S2) that delineate two long, structured loops. Nucleotide substitutions that disrupt either pseudoknot stem greatly reduced helper-Ty1-mediated retrotransposition of a mini-Ty1, but only mutations in S2 destabilized mini-Ty1 RNA in cis and helper-Ty1 RNA in trans. Nested in different loops of the pseudoknot are two hairpins with complementary 7-nucleotide motifs at their apices. Nucleotide substitutions in either motif also reduced retrotransposition and destabilized mini- and helper-Ty1 RNA. Compensatory mutations that restore base-pairing in the S2 stem or between the hairpins rescued retrotransposition and RNA stability in cis and trans. These data inform a model whereby a Ty1 RNA kissing complex with two intermolecular kissing-loop interactions initiates dimerization and packaging

Genetic dissection of the glutamatergic neuron system in cerebral cortex.

Diverse types of glutamatergic pyramidal neurons mediate the myriad processing streams and output channels of the cerebral cortex1,2, yet all derive from neural progenitors of the embryonic dorsal telencephalon3,4. Here we establish genetic strategies and tools for dissecting and fate-mapping subpopulations of pyramidal neurons on the basis of their developmental and molecular programs. We leverage key transcription factors and effector genes to systematically target temporal patterning programs in progenitors and differentiation programs in postmitotic neurons. We generated over a dozen temporally inducible mouse Cre and Flp knock-in driver lines to enable the combinatorial targeting of major progenitor types and projection classes. Combinatorial strategies confer viral access to subsets of pyramidal neurons defined by developmental origin, marker expression, anatomical location and projection targets. These strategies establish an experimental framework for understanding the hierarchical organization and developmental trajectory of subpopulations of pyramidal neurons that assemble cortical processing networks and output channels

The Public Repository of Xenografts enables discovery and randomized phase II-like trials in mice

More than 90% of drugs with preclinical activity fail in human trials, largely due to insufficient efficacy. We hypothesized that adequately powered trials of patient-derived xenografts (PDX) in mice could efficiently define therapeutic activity across heterogeneous tumors. To address this hypothesis, we established a large, publicly available repository of well-characterized leukemia and lymphoma PDXs that undergo orthotopic engraftment, called the Public Repository of Xenografts (PRoXe). PRoXe includes all de-identified information relevant to the primary specimens and the PDXs derived from them. Using this repository, we demonstrate that large studies of acute leukemia PDXs that mimic human randomized clinical trials can characterize drug efficacy and generate transcriptional, functional, and proteomic biomarkers in both treatment-naive and relapsed/refractory disease

CEO succession and the CEO’s commitment to the status quo

Chief executive officer (CEO) commitment to the status quo (CSQ) is expected to play an important role in any firm’s strategic adaptation. CSQ is used often as an explanation for strategic change occurring after CEO succession: new CEOs are expected to reveal a lower CSQ than established CEOs. Although widely accepted in the literature, this relationship remains imputed but unobserved. We address this research gap and analyze whether new CEOs reveal lower CSQ than established CEOs. By analyzing the letters to the shareholders of German HDAX firms, we find empirical support for our hypothesis of a lower CSQ of newly appointed CEOs compared to established CEOs. However, our detailed analyses provide a differentiated picture. We find support for a lower CSQ of successors after a forced CEO turnover compared to successors after a voluntary turnover, which indicates an influence of the mandate for change on the CEO’s CSQ. However, against the widespread assumption, we do not find support for a lower CSQ of outside successors compared to inside successors, which calls for deeper analyses of the insiderness of new CEOs. Further, our supplementary analyses propose a revised tenure effect: the widely assumed relationship of an increase in CSQ when CEO tenure increases might be driven mainly by the event of CEO succession and may not universally and continuously increase over time, pointing to a “window of opportunity” to initiate strategic change shortly after the succession event. By analyzing the relationship between CEO succession and CEO CSQ, our results contribute to the CSQ literature and provide fruitful impulses for the CEO succession literature

Évaluation de la biréfringence en ligne et modélisation du procédé de soufflage de gaine multicouche

Our objective is to develop tools that will allow us to improve our knowledge of the multilayer film blowing process. In order to gain general knowledge of the process an experimental campaign was realized to identify the effect of the main processing conditions on the radius, birefringence and temperature profile of monolayer and multilayer bubbles. We were able to observe that the layer position had almost no effect on radius and stress profiles. A Newtonian thermo mechanical model that describes the multilayer film blowing process was developed. A sensibility analysis was undertaken. The calculation allowed us to identify the conditions which could lead to a faster blowing of multilayer bubble in comparison to the blowing of their one layer counterpart. Generally the calculated variables (radius, temperature and stress) are in good agreement with the experimental data obtained from both monolayer and multilayer film blowing.Notre objectif est de développer des outils permettant une meilleure compréhension du procédé de soufflage de gaines multicouches. Afin de mieux comprendre le procédé, une campagne expérimentale a été réalisée afin d¤identifier l¤effet des conditions opératoires sur l¤évolution du rayon, de la biréfringence et de la température de gaines monocouches et multicouches. Il a été possible de constater que l¤agencement des différentes couches affectait peu le gonflement et les contraintes à l¤intérieur du film. Un modèle thermomécanique permettant de décrire le soufflage de gaine multicouche a été développé. Par la suite une étude de sensibilité a été réalisée. Nous avons constaté que, dans certaines conditions, il était possible que les films multicouches gonflent plus rapidement que les films monocouches. Les résultats de calcul permettent de reproduire adéquatement l¤évolution du rayon, de la température et des contraintes survenant lors de la production de gaines monocouches et multicouches

Évaluation de la biréfringence en ligne et modélisation du procédé de soufflage de gaine multicouche

PARIS-MINES ParisTech (751062310) / SudocSOPHIA ANTIPOLIS-Mines ParisTech (061522302) / SudocSudocFranceF

Property protection factor -- Australasian Fire Authorities Council

The objective of this project was to form recommendations on whether or not to explicitly include property protection into the Building Code of Australia (BCA). Numerous discussions were held with key professionals in Australia's fire industry, along with examination of statistics and relevant case studies to provide the recommendations. The project team came to the conclusion that there is currently not enough data to support an objective change to the BCA, and more research must be conducted

Train Fire Modeling with FDS

This project was undertaken to model a full scale train fire using Fire Dynamics Simulator (FDS). Previous modeling efforts predicted earlier flashover and higher heat release rates than in the actual experiment. An analysis to quantify newspapers as an ignition source was performed and the ignition area was remodeled based on newspaper ignition tests. Improvements were made to material sub-models. Full simulations were conducted, resulting in a more accurate full scale model

5′ to 3′ mRNA Decay Factors Colocalize with Ty1 Gag and Human APOBEC3G and Promote Ty1 Retrotransposition▿ ‡

The genomic RNA of retroviruses and retrovirus-like transposons must be sequestered from the cellular translational machinery so that it can be packaged into viral particles. Eukaryotic mRNA processing bodies (P bodies) play a central role in segregating cellular mRNAs from the translational machinery for storage or decay. In this work, we provide evidence that the RNA of the Saccharomyces cerevisiae Ty1 retrotransposon is packaged into virus-like particles (VLPs) in P bodies. Ty1 RNA is translationally repressed, and Ty1 Gag, the capsid and RNA binding protein, accumulates in discrete cytoplasmic foci, a subset of which localize to P bodies. Human APOBEC3G, a potent Ty1 restriction factor that is packaged into Ty1 VLPs via an interaction with Gag, also localizes to P bodies. The association of APOBEC3G with P bodies does not require Ty1 element expression, suggesting that P-body localization of APOBEC3G and Ty1 Gag precedes VLP assembly. Additionally, we report that two P-body-associated 5′ to 3′ mRNA decay pathways, deadenylation-dependent mRNA decay (DDD) and nonsense-mediated decay (NMD), stimulate Ty1 retrotransposition. The additive contributions of DDD and NMD explain the strong requirement for general 5′ to 3′ mRNA degradation factors Dcp1, Dcp2, and Xrn1 in Ty1 retromobility. 5′ to 3′ decay factors act at a posttranslational step in retrotransposition, and Ty1 RNA packaging into VLPs is abolished in the absence of the 5′ to 3′ exonuclease Xrn1. Together, the results suggest that VLPs assemble in P bodies and that 5′ to 3′ mRNA decay is essential for the packaging of Ty1 RNA in VLPs