Collège de France

About: Collège de France is a education organization based out in Paris, France. It is known for research contribution in the topics: Population & Receptor. The organization has 6541 authors who have published 11983 publications receiving 648742 citations. The organization is also known as: College de France.

Disc-Like Mesogens: A Classification

Abstract: Five mesomorphic phases are described in several disc-like liquid-crystals. They are hexalkanoyloxy benzenes, triphenylenes or truxenes, hexa-alkoxy triphenylenes, hexa-benzoates of triphenylene. Several of these compounds exhibit a complex polymorphism. Informations on the structures of these phases have been obtained by means of X-Ray diffraction; except a Nd namatic phase all the others one are columnar phases. At the same time a systematic study has been performed by the well known method of isomorphy. All these results allow us to propose a general classification of these phases.

Search for charged Higgs bosons : combined results using LEP data

Abstract: The four LEP collaborations, ALEPH, DELPHI, L3 and OPAL, have searched for pair-produced charged Higgs bosons in the framework of Two Higgs Doublet Models (2HDMs). The data of the four experiments are statistically combined. The results are interpreted within the 2HDM for Type I and Type II benchmark scenarios. No statistically significant excess has been observed when compared to the Standard Model background prediction, and the combined LEP data exclude large regions of the model parameter space. Charged Higgs bosons with mass below 80 GeV/c^2 (Type II scenario) or 72.5 GeV/c^2 (Type I scenario, for pseudo-scalar masses above 12 GeV/c^2) are excluded at the 95% confidence level.

Estrous cycle effects on behavior of C57BL/6J and BALB/cByJ female mice: implications for phenotyping strategies

Abstract: Systematic behavioral phenotyping of genetically modified mice is a powerful method with which to identify the molecular factors implicated in control of animal behavior, with potential relevance for research into neuropsychiatric disorders. A number of such disorders display sex differences, yet the use of female mice in phenotyping strategies has been a rare practice because of the potential variability related to the estrous cycle. We have now investigated the behavioral effects of the estrous cycle in a battery of behavioral tests in C57BL/6J and BALB/cByJ inbred strains of mice. Whereas the performance of BALB/cByJ female mice varied significantly depending on the phase of the estrous cycle in the open field, tail flick and tail suspension tests, the behavior of C57BL/6J females, with the exception of the tail suspension performance, remained stable across all four phases of the estrous cycle in all of the tests including open field, rotarod, startle reflex and pre-pulse inhibition, tail flick and hot plate. We also found that irrespective of the estrous cycle, the behavior of C57BL/6J females was different from that of BALB/cByJ groups in all of the behavioral paradigms. Such strain differences were previously reported in male comparisons, suggesting that the same inter-group differences can be revealed by studying female or male mice. In addition, strain differences were evident even for behaviors that were susceptible to estrous cycle modulations, although their detection might necessitate the constitution of large experimental groups.

Neurophysiological dynamics of phrase-structure building during sentence processing

Abstract: Although sentences unfold sequentially, one word at a time, most linguistic theories propose that their underlying syntactic structure involves a tree of nested phrases rather than a linear sequence of words. Whether and how the brain builds such structures, however, remains largely unknown. Here, we used human intracranial recordings and visual word-by-word presentation of sentences and word lists to investigate how left-hemispheric brain activity varies during the formation of phrase structures. In a broad set of language-related areas, comprising multiple superior temporal and inferior frontal sites, high-gamma power increased with each successive word in a sentence but decreased suddenly whenever words could be merged into a phrase. Regression analyses showed that each additional word or multiword phrase contributed a similar amount of additional brain activity, providing evidence for a merge operation that applies equally to linguistic objects of arbitrary complexity. More superficial models of language, based solely on sequential transition probability over lexical and syntactic categories, only captured activity in the posterior middle temporal gyrus. Formal model comparison indicated that the model of multiword phrase construction provided a better fit than probability-based models at most sites in superior temporal and inferior frontal cortices. Activity in those regions was consistent with a neural implementation of a bottom-up or left-corner parser of the incoming language stream. Our results provide initial intracranial evidence for the neurophysiological reality of the merge operation postulated by linguists and suggest that the brain compresses syntactically well-formed sequences of words into a hierarchy of nested phrases.

G–quadruplex RNA structure as a signal for neurite mRNA targeting

Abstract: Targeting of messenger RNAs (mRNAs) in neuron processes relies on cis-acting regulatory elements, the nature of which is poorly understood. Here, we report that approximately 30% of the best-known dendritic mRNAs contain a guanine (G)–quadruplex consensus in their 3′-untranslated region. Among these mRNAs, we show by using RNA structure probing that a G–quadruplex is present in the mRNAs of two key postsynaptic proteins: PSD-95 and CaMKIIa. The G–quadruplex structure is necessary and sufficient for the potent and fast localization of mRNAs in cortical neurites and this occurs in a metabotropic glutamate receptor-responsive manner. Thus, G–quadruplex seems to be a common neurite localization signal.