55 research outputs found

    Dimensionality dependent electronic structure of the exfoliated van der Waals antiferromagnet NiPS3_3

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    Resonant Inelastic X-ray Scattering (RIXS) was used to measure the local electronic structure in few-layer exfoliated flakes of the van der Waals antiferromagnet NiPS3_3. The resulting spectra show a systematic softening and broadening of NiS6NiS_6 multiplet excitations with decreasing layer count from the bulk to three atomic layers (3L). These trends are driven by a decrease in the transition metal-ligand and ligand-ligand hopping integrals, and in the charge-transfer energy: Δ\Delta = 0.60 eV in the bulk and 0.22 eV in 3L NiPS3_3. Relevant intralayer magnetic exchange integrals computed from the electronic parameters exhibit a systematic decrease in the average interaction strength with thickness and place 2D NiPS3_3 close to the phase boundary between stripy and spiral antiferromagnetic order, which may explain the apparent vanishing of long-range order in the 2D limit. This study explicitly demonstrates the influence of interinterlayer electronic interactions on intraintralayer ones in insulating magnets. As a consequence, the magnetic Hamiltonian in few-layer insulating magnets can be significantly different from that in the bulk.Comment: 5 pages, 4 figures; additional 9 pages and 13 figures of supplementary informatio

    Do inattention and hyperactivity symptoms equal scholastic impairment? evidence from three European cohorts

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    Background Attention Deficit/Hyperactivity Disorder (ADHD) affects many children, adolescents, and adults and is associated with a number of impairments. Poor academic performance is related to ADHD in clinical samples. However, it is unclear to what extent core ADHD symptoms and scholastic impairment are related in non-referred school-aged children. Methods Data come from three population-based cohorts from Sweden, Denmark, and Finland, which are part of the Nordic Network on ADHD. The combined sample size was 13,087 children who were studied at ages 7–8 or 10–12 years. Teachers rated children on inattention and hyperactivity symptoms and reported children's scholastic performance on basic skills. Results There was a significant association in all cohorts between core ADHD symptoms and scholastic impairment in reading, writing, and mathematics. Particularly, inattention was related to a two to tenfold increase in scholastic impairment. Prevalence of hyperactivity symptoms was similar across the three cohorts, but inattention was lowest among children from the Finnish cohort, after stratification on living conditions. Conclusion These results extend previous reports of scholastic impairment among children with clinically diagnosed ADHD to non-referred population samples from three European countries. Surveillance policies should be implemented in school systems to catch children in need of behavioral or scholastic support early

    DBcat: a catalog of biological databases.

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    The DBcat (http://www.infobiogen.fr/services/dbcat) is a comprehensive catalog of biological databases, maintained and curated on a daily basis at GIS Infobiogen. It contains more than 400 databases classified by application domains. The DBcat is a structured flat file library, that can be searched by means of an SRS server or a dedicated Web interface. The files are available for downloading from Infobiogen anonymous ftp server

    Loss of STAT6 leads to anchorage-independent growth and trastuzumab resistance in HER2+ breast cancer cells.

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    Approximately 20% of breast cancers are HER2-positive. Trastuzumab has improved patient outcomes significantly for these cancers. However, acquired resistance remains a major hurdle in the clinical management of these patients. Therefore, identifying molecular changes that cause trastuzumab resistance is worthwhile. STAT6 is a transcription factor that regulates a variety of genes involved in cell cycle regulation, growth inhibition, and apoptosis. STAT6 expression is lost in approximately 3% of breast cancers, but little work has been done in the context of trastuzumab resistance in breast cancer. In isogenic cell line pairs, we observed that trastuzumab-resistant cells expressed significantly lower levels of STAT6 compared to trastuzumab-sensitive cells. Therefore, in order to study the consequences of STAT6 loss in HER2+ breast cancer, we knocked out both alleles of the STAT6 gene using somatic cell gene targeting. Interestingly, loss of STAT6 resulted in anchorage-independent growth and changes in several genes involved in epithelial to mesenchymal transition. This study suggests that STAT6 may play a role in the pathophysiology of HER2+ human breast cancer

    Water safety: Age-specific changes in knowledge and attitudes following a school-based intervention

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    Objectives: To explore whether an intervention during mandatory schooling can lead to age-specific changes in water safety knowledge and attitudes. Methods: Age-specific questionnaires were distributed to 202 kindergarten and grade one pupils, 220 elementary school pupils and 337 pupils attending the first three high school grades in Greater Athens. The information was used to design an educational package that was subsequently presented to pupils of the same grades and similar socio-demographic profiles attending different schools in the same area. One month later, a post-exposure evaluation was conducted using the initial questionnaires, in which 115, 205 and 321 pupils from the respective grade categories provided their responses. In order to compare the performance of pupils exposed to the educational intervention with that of pupils who participated only in the initial assessment, mean differences in scores measuring overall knowledge and attitudes were estimated within each of the three grade groups adjusting for age, gender, sibship size, maternal education and swimming knowledge. Results: Among kindergarten and grade one pupils, those who received the intervention scored significantly higher for knowledge (17.40%, 95% Cl 6.41 % to 28.39%) and attitudes (23.64%, 95% Cl 4.48% to 42.79%). Among elementary school pupils the gains in knowledge were less evident (14.58%, 95% Cl -3.05% to 32.21%)) and almost null in attitudes (5.64%, 95% Cl -11.47% to 22.77%). Further advancement of age showed no improvement in knowledge (-0.15%, 95% Cl -5.30% to 4.99%) and a minimal, insignificant increase in attitudes (6.32%, 95% Cl -1.87% to 14.52%) among exposed high school pupils. Conclusion: The school-based intervention resulted in considerable positive changes in knowledge and attitudes among very young pupils. Elementary schooling seems to provide meagre opportunities to simply improve knowledge. Alternative/complementary approaches should be sought in any attempt to modify behavior
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