Periodically Spaced CaF2_2 Semi-Insulating Thin Ribbons Growth Study on the Si(100) Surface

The use and the study of semi-insulating layers on metals and semiconductors surfaces have found continuous interest in the past decades. So far, the control of the sizes and growth location of the insulating islands on the substrate is either ill-defined or usually constrained to the use of evaporation masks which size can easily exceed tenth of nanometers. Here, we show that it is possible to grow self-organized periodically spaced thin ribbons of semi-insulating stripes on the bare Si(100) surface. The epitaxial growth of these structures is obtained by the evaporation of CaF$_2$ molecules on the silicon surface with a coverage of 1.2 monolayers. They are investigated via scanning tunneling techniques at low temperature (9K). The obtained ribbons exhibit a surface bandgap of ~3.2 eV as well as a resonant state at the central part of the ribbons at ~2.0 eV below the Fermi level energy. The use of the density functional theory allows suggesting a model structure of the observed ribbons and reproducing the experimental STM topographies. The formation of the thin ribbons is discussed and we point out the influence of the mechanical forces inside and between the structures that may influence their periodicity

Room temperature electronic template effect of pre-structured SmSi(111)-8x2 interface yielding self-aligned organic molecules

International audienceThis work describes an innovative concept for the development of organized molecular systems thanks to the template effect of the pre-structured semi-conductive SmSi(111) interface. This substrate was selected because Sm deposition in the submonolayer range leads to a 8x2-reconstruction, which is a well-defined one-dimensional semi-metallic structure. Adsorption of aromatic molecules (1,4-di-(9-ethynyltriptycenyl)-benzene) on SmSi(111)-8x2 and Si(111)-7x7 interfaces has been investigated by scanning tunneling microscopy (STM) at room temperature. Density functional theory (DFT) and semi-empirical (ASED+) calculations have been performed to define the nature of the molecular adsorption sites of the target molecule on SmSi as well as their self-alignment on this interface. Experimental data and theoretical results are in good agreement

Repressive LTR Nucleosome Positioning by the BAF Complex Is Required for HIV Latency

The SWI/SNF BAF chromatin remodeling complex generates a repressive nucleosome structure at the HIV LTR conducive to establishment and maintenance of HIV latency, while PBAF augments HIV transcription

Genome-wide association study of germline variants and breast cancer-specific mortality.

BackgroundWe examined the associations between germline variants and breast cancer mortality using a large meta-analysis of women of European ancestry.MethodsMeta-analyses included summary estimates based on Cox models of twelve datasets using ~10.4 million variants for 96,661 women with breast cancer and 7697 events (breast cancer-specific deaths). Oestrogen receptor (ER)-specific analyses were based on 64,171 ER-positive (4116) and 16,172 ER-negative (2125) patients. We evaluated the probability of a signal to be a true positive using the Bayesian false discovery probability (BFDP).ResultsWe did not find any variant associated with breast cancer-specific mortality at P < 5 × 10-8. For ER-positive disease, the most significantly associated variant was chr7:rs4717568 (BFDP = 7%, P = 1.28 × 10-7, hazard ratio [HR] = 0.88, 95% confidence interval [CI] = 0.84-0.92); the closest gene is AUTS2. For ER-negative disease, the most significant variant was chr7:rs67918676 (BFDP = 11%, P = 1.38 × 10-7, HR = 1.27, 95% CI = 1.16-1.39); located within a long intergenic non-coding RNA gene (AC004009.3), close to the HOXA gene cluster.ConclusionsWe uncovered germline variants on chromosome 7 at BFDP < 15% close to genes for which there is biological evidence related to breast cancer outcome. However, the paucity of variants associated with mortality at genome-wide significance underpins the challenge in providing genetic-based individualised prognostic information for breast cancer patients

Polygenic Risk Scores for Prediction of Breast Cancer and Breast Cancer Subtypes

Stratification of women according to their risk of breast cancer based on polygenic risk scores (PRSs) could improve screening and prevention strategies. Our aim was to develop PRSs, optimized for prediction of estrogen receptor (ER)-specific disease, from the largest available genome-wide association dataset and to empirically validate the PRSs in prospective studies. The development dataset comprised 94,075 case subjects and 75,017 control subjects of European ancestry from 69 studies, divided into training and validation sets. Samples were genotyped using genome-wide arrays, and single-nucleotide polymorphisms (SNPs) were selected by stepwise regression or lasso penalized regression. The best performing PRSs were validated in an independent test set comprising 11,428 case subjects and 18,323 control subjects from 10 prospective studies and 190,040 women from UK Biobank (3,215 incident breast cancers). For the best PRSs (313 SNPs), the odds ratio for overall disease per 1 standard deviation in ten prospective studies was 1.61 (95%CI: 1.57-1.65) with area under receiver-operator curve (AUC) = 0.630 (95%CI: 0.628-0.651). The lifetime risk of overall breast cancer in the top centile of the PRSs was 32.6%. Compared with women in the middle quintile, those in the highest 1% of risk had 4.37- and 2.78-fold risks, and those in the lowest 1% of risk had 0.16- and 0.27-fold risks, of developing ER-positive and ER-negative disease, respectively. Goodness-of-fit tests indicated that this PRS was well calibrated and predicts disease risk accurately in the tails of the distribution. This PRS is a powerful and reliable predictor of breast cancer risk that may improve breast cancer prevention programs.NovartisEli Lilly and CompanyAstraZenecaAbbViePfizer UKCelgeneEisaiGenentechMerck Sharp and DohmeRocheCancer Research UKGovernment of CanadaArray BioPharmaGenome CanadaNational Institutes of HealthEuropean CommissionMinistère de l'Économie, de l’Innovation et des Exportations du QuébecSeventh Framework ProgrammeCanadian Institutes of Health Researc

Genome-wide association study of germline variants and breast cancer-specific mortality

BACKGROUND: We examined the associations between germline variants and breast cancer mortality using a large meta-analysis of women of European ancestry. METHODS: Meta-analyses included summary estimates based on Cox models of twelve datasets using ~10

Etude sous pression partielle d'oxygene et a haute temperature de l'evolution de la conductivite dans les structures perovskites: application a l'etude du titanate de baryum pur ou dope en accepteur

SIGLEAvailable from INIST (FR), Document Supply Service, under shelf-number : T 84618 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Theoretical study of ciprofloxacin antibiotic trapping on grapheneor boron nitride oxide nanoflakes

International audience<span style="left: 85.0393px; top: 398.177px; font-size: 16.6043px; font-family: serif; transform: scaleX(0.99095);"&gtReactions between the antibacterial fluoroquinolone agent ciprofloxacin (CIP) and organic hydrophilic nanoflakes (graphene</span&gt<span style="left: 85.0393px; top: 418.869px; font-size: 16.6043px; font-family: serif; transform: scaleX(0.993399);"&gtoxide and boron nitride oxide) have been studied in aqueous medium using density functional theory (DFT), time-dependent</span&gt<span style="left: 85.0393px; top: 439.656px; font-size: 16.6043px; font-family: serif; transform: scaleX(0.977307);"&gtdensity functional theory (TD-DFT), and molecular dynamics (MD) simulations. We found that CIP molecules in</span&gt<span style="left: 826.013px; top: 434.575px; font-size: 16.6043px; font-family: sans-serif;"&gtπ</span&gt<span style="left: 835.934px; top: 439.656px; font-size: 16.6043px; font-family: serif;"&gt-</span&gt<span style="left: 841.131px; top: 434.575px; font-size: 16.6043px; font-family: sans-serif;"&gtπ</span&gt<span style="left: 855.399px; top: 439.656px; font-size: 16.6043px; font-family: serif; transform: scaleX(0.969708);"&gtelectron</span&gt<span style="left: 85.0393px; top: 460.443px; font-size: 16.6043px; font-family: serif; transform: scaleX(0.97967);"&gtdonor</span&gt<span style="left: 122.834px; top: 455.362px; font-size: 16.6043px; font-family: sans-serif;"&gt–</span&gt<span style="left: 131.055px; top: 460.443px; font-size: 16.6043px; font-family: serif; transform: scaleX(0.976085);"&gtacceptor (EDA) reaction preserve their optical properties in water when adsorbed on hydrophilic nanoflakes. Moreover,</span&gt<span style="left: 85.0393px; top: 481.136px; font-size: 16.6043px; font-family: serif; transform: scaleX(0.953144);"&gtMD calculations aimed at studying the diffusive translocation of CIP to lipid membrane showed that the choice of the hydrophilic</span&gt<span style="left: 85.0393px; top: 501.923px; font-size: 16.6043px; font-family: serif; transform: scaleX(0.97707);"&gtnanovectors is primordial to stabilize the molecule on the cellular membrane and improve cytotoxic effects.</span&g

Periodically Spaced CaF2 Semi-Insulating Thin Ribbons Growth Study on the Si(100) Surface

International audienceThe use and the study of semi-insulating layers on metals and semiconductors surfaces have found continuous interest in the past decades. So far, the control of the sizes and growth location of the insulating islands on the substrate is either ill-defined or usually constrained to the use of evaporation masks which size can easily exceed tenth of nanometers. Here, we show that it is possible to grow selforganized periodically spaced thin ribbons of semi-insulating stripes on the bare Si(100) surface. The epitaxial growth of these structures is obtained by the evaporation of CaF2 molecules on the silicon surface with a coverage of 1.2 monolayers. They are investigated via scanning tunneling techniques at low temperature (9K). The obtained ribbons exhibit a surface bandgap of ~3.2 eV as well as a resonant state at the central part of the ribbons at ~2.0 eV below the Fermi level energy. The use of the density functional theory allows suggesting a model structure of the observed ribbons and reproducing the experimental STM topographies. The formation of the thin ribbons is discussed and we point out the influence of the mechanical forces inside and between the structures that may influence their periodicity