Controlling the polarization eigenstate of a quantum dot exciton with light

We demonstrate optical control of the polarization eigenstates of a neutral quantum dot exciton without any external fields. By varying the excitation power of a circularly polarized laser in micro-photoluminescence experiments on individual InGaAs quantum dots we control the magnitude and direction of an effective internal magnetic field created via optical pumping of nuclear spins. The adjustable nuclear magnetic field allows us to tune the linear and circular polarization degree of the neutral exciton emission. The quantum dot can thus act as a tunable light polarization converter.Comment: 5 pages, 3 figure

Genetic association study of QT interval highlights role for calcium signaling pathways in myocardial repolarization.

The QT interval, an electrocardiographic measure reflecting myocardial repolarization, is a heritable trait. QT prolongation is a risk factor for ventricular arrhythmias and sudden cardiac death (SCD) and could indicate the presence of the potentially lethal mendelian long-QT syndrome (LQTS). Using a genome-wide association and replication study in up to 100,000 individuals, we identified 35 common variant loci associated with QT interval that collectively explain ∼8-10% of QT-interval variation and highlight the importance of calcium regulation in myocardial repolarization. Rare variant analysis of 6 new QT interval-associated loci in 298 unrelated probands with LQTS identified coding variants not found in controls but of uncertain causality and therefore requiring validation. Several newly identified loci encode proteins that physically interact with other recognized repolarization proteins. Our integration of common variant association, expression and orthogonal protein-protein interaction screens provides new insights into cardiac electrophysiology and identifies new candidate genes for ventricular arrhythmias, LQTS and SCD

Using rare genetic mutations to revisit structural brain asymmetry

Asymmetry between the left and right hemisphere is a key feature of brain organization. Hemispheric functional specialization underlies some of the most advanced human-defining cognitive operations, such as articulated language, perspective taking, or rapid detection of facial cues. Yet, genetic investigations into brain asymmetry have mostly relied on common variants, which typically exert small effects on brain-related phenotypes. Here, we leverage rare genomic deletions and duplications to study how genetic alterations reverberate in human brain and behavior. We designed a pattern-learning approach to dissect the impact of eight high-effect-size copy number variations (CNVs) on brain asymmetry in a multi-site cohort of 552 CNV carriers and 290 non-carriers. Isolated multivariate brain asymmetry patterns spotlighted regions typically thought to subserve lateralized functions, including language, hearing, as well as visual, face and word recognition. Planum temporale asymmetry emerged as especially susceptible to deletions and duplications of specific gene sets. Targeted analysis of common variants through genome-wide association study (GWAS) consolidated partly diverging genetic influences on the right versus left planum temporale structure. In conclusion, our gene-brain-behavior data fusion highlights the consequences of genetically controlled brain lateralization on uniquely human cognitive capacities

Identification of novel RNA secondary structures within the hepatitis C virus genome reveals a cooperative involvement in genome packaging

The specific packaging of the hepatitis C virus (HCV) genome is hypothesised to be driven by Core- RNA interactions. To identify the regions of the viral genome involved in this process, we used SELEX (systematic evolution of ligands by exponential enrichment) to identify RNA aptamers which bind specifically to Core in vitro. Comparison of these aptamers to multiple HCV genomes revealed the presence of a conserved terminal loop motif within short RNA stem-loop structures. We postulated that interactions of these motifs, as well as sub-motifs which were present in HCV genomes at statistically significant levels, with the Core protein may drive virion assembly. We mutated 8 of these predicted motifs within the HCV infectious molecular clone JFH-1, thereby producing a range of mutant viruses predicted to possess altered RNA secondary structures. RNA replication and viral titre were unaltered in viruses possessing only one mutated structure. However, infectivity titres were decreased in viruses possessing a higher number of mutated regions. This work thus identified multiple novel RNA motifs which appear to contribute to genome packaging. We suggest that these structures act as cooperative packaging signals to drive specific RNA encapsidation during HCV assembly

Genome-wide association analyses identify new Brugada syndrome risk loci and highlight a new mechanism of sodium channel regulation in disease susceptibility.

Brugada syndrome (BrS) is a cardiac arrhythmia disorder associated with sudden death in young adults. With the exception of SCN5A, encoding the cardiac sodium channel Na1.5, susceptibility genes remain largely unknown. Here we performed a genome-wide association meta-analysis comprising 2,820 unrelated cases with BrS and 10,001 controls, and identified 21 association signals at 12 loci (10 new). Single nucleotide polymorphism (SNP)-heritability estimates indicate a strong polygenic influence. Polygenic risk score analyses based on the 21 susceptibility variants demonstrate varying cumulative contribution of common risk alleles among different patient subgroups, as well as genetic associations with cardiac electrical traits and disorders in the general population. The predominance of cardiac transcription factor loci indicates that transcriptional regulation is a key feature of BrS pathogenesis. Furthermore, functional studies conducted on MAPRE2, encoding the microtubule plus-end binding protein EB2, point to microtubule-related trafficking effects on Na1.5 expression as a new underlying molecular mechanism. Taken together, these findings broaden our understanding of the genetic architecture of BrS and provide new insights into its molecular underpinnings

"La chouette de Minerve". Du sacré au merveilleux chez le littérateur Michel Leiris

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Désordres hépatiques en cours de grossesse chez les femmes infectées par le VIH

PARIS7-Xavier Bichat (751182101) / SudocSudocFranceF

Les nouvelles cultures de l accompagnement : les soins palliatifs, une voie spirituelle dans une société de la performance

L accompagnement , qui se développe rapidement dans la plupart des champs de la société française (éducation, social, santé, travail ), semble aujourd hui constituer un phénomène social total. Dans ses formes générales, il est le reflet d une culture obnubilée par l objectif (avec l adhésion du sujet), le résultat (avec l obsession des projets et des projections), et le faire (avec la survalorisation de la compétence). Il ressort, de la sorte, que l accompagnement tend paradoxalement à produire de la solitude dans le contexte général d une société de la performance. L accompagnement des personnes en fin de vie, à l inverse, s en distingue radicalement. La culture spécifique qu il véhicule repose sur la place déterminante de la souffrance spirituelle , au cœur de la souffrance globale. Sur ce fondement spirituel , l accompagnement en fin de vie promeut une approche essentiellement subjective (par l adaptation au sujet), préconise un certain détachement du résultat (par l attention au présent), et invite plutôt à une profondeur d être (par l accent mis sur la présence dans la relation), dans un contexte où la notion de performance est peu signifiante. Pourtant, dans sa manière d associer science médicale et science humaine, la culture palliative se révèle porteuse d une ambition synthétique majeure : celle de tracer à grande échelle une voie qui conjugue la compétence professionnelle et la qualité de présence (le geste habité ), l objectif et le subjectif, le projet et le détachement, la performance et la simplicité... La culture palliative révèle ainsi une modernité saisissante en ce qu elle invite à penser autrement l action et le rapport à l autre.In France, many support operations, in fields like education, teaching, social support, health, work tend to be conducted through the global French concept of accompagnement . This word does not have a single equivalence in English, where it is met under various names (support, care, coaching, counsel ). These supportive actions refer to a global culture based upon achievement of objectives, priority granted to action, competence, results... and submission of the subject. Hence, these accompagnements surprisingly appear to produce more solitude in the general context of a society obsessed by performance. On the other hand, the same word of accompagnement is used to describe end of life care (although this word has a wider meaning than the word care has). By showing that the very central aspect of total pain is the spiritual pain itself, end of life accompagnement appears to promote a specifically spiritual culture. This culture relies upon on the adaptation to the subject, the ability to be (savoir-être) instead of the ability to do, the attention to the relationship, and a certain detachment from the result by focusing on present time, in a context where the idea of performance is rather inappropriate. However, in its requirements to combine medical science and relationship science , palliative culture seems to open an ambitious way where professional competence and quality of presence, objectivity and subjectivity, project and detachment from the result, performance and simplicity are expected to be combined. Hence, palliative culture appears to be of a striking modernity in its original way to consider action and relationship with others.PARIS-EPHE-Sciences religieuses (751052336) / SudocSudocFranceF