106 research outputs found

    Spin Reversal of a Quantum Hall Ferromagnet at a Landau Level Crossing

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    When Landau levels (LLs) become degenerate near the Fermi energy in the quantum Hall regime, interaction effects can drastically modify the electronic ground state. We study the quantum Hall ferromagnet formed in a two-dimensional hole gas around the LL filling factor Μ=1\nu=1 in the vicinity of a LL crossing in the heave-hole valence band. Cavity spectroscopy in the strong-coupling regime allows us to optically extract the two-dimensional hole gas' spin polarization. By analyzing this polarization as a function of hole density and magnetic field, we observe a spin flip of the ferromagnet. Furthermore, the depolarization away from Μ=1\nu=1 accelerates close to the LL crossing. This is indicative of an increase in the size of Skyrmion excitations as the effective Zeeman energy vanishes at the LL crossing

    Alcohol Consumption, Genetic Variants in Alcohol Deydrogenases, and Risk of Cardiovascular Diseases: A Prospective Study and Meta-Analysis

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    OBJECTIVE: First, to investigate and compare associations between alcohol consumption and variants in alcohol dehydrogenase (ADH) genes with incidence of cardiovascular diseases (CVD) in a large German cohort. Second, to quantitatively summarize available evidence of prospective studies on polymorphisms in ADH1B and ADH1C and CVD-risk. METHODS: We conducted a case-cohort study nested within the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam cohort including a randomly drawn subcohort (n = 2175) and incident cases of myocardial infarction (MI; n = 230) or stroke (n = 208). Mean follow-up time was 8.2±2.2 years. The association between alcohol consumption, ADH1B or ADH1C genotypes, and CVD-risk was assessed using Cox proportional hazards regression. Additionally, we report results on associations of variants in ADH1B and ADH1C with ischemic heart disease and stroke in the context of a meta-analysis of previously published prospective studies published up to November 2011. RESULTS: Compared to individuals who drank >0 to 6 g alcohol/d, we observed a reduced risk of MI among females consuming >12 g alcohol/d (HR = 0.31; 95% CI: 0.10-0.97) and among males consuming >24 to 60 g/d (HR = 0.57; 95% CI: 0.33-0.98) or >60 g alcohol/d (HR = 0.30; 95% CI: 0.12-0.78). Stroke risk was not significantly related to alcohol consumption >6 g/d, but we observed an increased risk of stroke in men reporting no alcohol consumption. Individuals with the slow-coding ADH1B*1/1 genotype reported higher median alcohol consumption. Yet, polymorphisms in ADH1B or ADH1C were not significantly associated with risk of CVD in our data and after pooling results of eligible prospective studies [ADH1B*1/1: RR = 1.35 (95% CI: 0.98-1.88; p for heterogeneity: 0.364); ADH1C*2/2: RR = 1.07 (95% CI: 0.90-1.27; p for heterogeneity: 0.098)]. CONCLUSION: The well described association between alcohol consumption and CVD-risk is not reflected by ADH polymorphisms, which modify the rate of ethanol oxidation

    An international clinical study of ability and disability in ADHD using the WHO-ICF framework

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    This is the fourth and final study designed to develop International Classification of Functioning, Disability and Health (ICF, and children and youth version, ICF-CY) core sets for attention-deficit hyperactivity disorder (ADHD). To investigate aspects of functioning and environment of individuals with ADHD as documented by the ICF-CY in clinical practice settings. An international cross-sectional multi-centre study was applied, involving nine units from eight countries: Denmark, Germany, India, Italy, Portugal, Saudi Arabia, Sweden and Taiwan. Clinicians and clinical researchers rated the functioning level of 112 children, adolescents and adults with ADHD using the extended ICF-CY checklist version 2.1a. The ratings were based on a variety of information sources, such as medical records, medical history, clinical observations, clinical questionnaires, psychometric tests and structured interviews with participants and family members. In total, 113 ICF-CY categories were identified, of which 50 were related to the activities and participation, 33 to environmental factors and 30 to body functions. The clinical study also yielded strengths related to ADHD, which included temperament and personality functions and recreation and leisure. The study findings endorse the complex nature of ADHD, as evidenced by the many functional and contextual domains impacted in ADHD. ICF-CY based tools can serve as foundation for capturing various functional profiles and environmental facilitators and barriers. The international nature of the ICF-CY makes it possible to develop user-friendly tools that can be applied globally and in multiple settings, ranging from clinical services and policy-making to education and research

    Combined impact of healthy lifestyle factors on colorectal cancer: a large European cohort study

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    Background: Excess body weight, physical activity, smoking, alcohol consumption and certain dietary factors are individually related to colorectal cancer (CRC) risk; however, little is known about their joint effects. The aim of this study was to develop a healthy lifestyle index (HLI) composed of five potentially modifiable lifestyle factors – healthy weight, physical activity, non-smoking, limited alcohol consumption and a healthy diet, and to explore the association of this index with CRC incidence using data collected within the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort. Methods: In the EPIC cohort, a total of 347,237 men and women, 25- to 70-years old, provided dietary and lifestyle information at study baseline (1992 to 2000). Over a median follow-up time of 12 years, 3,759 incident CRC cases were identified. The association between a HLI and CRC risk was evaluated using Cox proportional hazards regression models and population attributable risks (PARs) have been calculated. Results: After accounting for study centre, age, sex and education, compared with 0 or 1 healthy lifestyle factors, the hazard ratio (HR) for CRC was 0.87 (95% confidence interval (CI): 0.44 to 0.77) for two factors, 0.79 (95% CI: 0.70 to 0.89) for three factors, 0.66 (95% CI: 0.58 to 0.75) for four factors and 0.63 (95% CI: 0.54 to 0.74) for five factors; P-trend <0.0001. The associations were present for both colon and rectal cancers, HRs, 0.61 (95% CI: 0.50 to 0.74; P for trend <0.0001) for colon cancer and 0.68 (95% CI: 0.53 to 0.88; P-trend <0.0001) for rectal cancer, respectively (P-difference by cancer sub-site = 0.10). Overall, 16% of the new CRC cases (22% in men and 11% in women) were attributable to not adhering to a combination of all five healthy lifestyle behaviours included in the index. Conclusions: Combined lifestyle factors are associated with a lower incidence of CRC in European populations characterized by western lifestyles. Prevention strategies considering complex targeting of multiple lifestyle factors may provide practical means for improved CRC prevention. Electronic supplementary material The online version of this article (doi:10.1186/s12916-014-0168-4) contains supplementary material, which is available to authorized users

    Insertional mutagenesis identifies multiple networks of cooperating genes driving intestinal tumorigenesis

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    The evolution of colorectal cancer suggests the involvement of many genes. We performed insertional mutagenesis with the Sleeping Beauty (SB) transposon system in mice carrying germline or somatic Apc mutation. Analysis of common insertion sites (CISs) isolated from 446 tumors revealed many hundreds of candidate cancer drivers. Comparison to human datasets suggested that 234 CIS genes are also deregulated in human colorectal cancers. 183 CIS genes are candidate Wnt targets, and 20 are shown to be novel modifiers of canonical Wnt signaling. We also identified gene mutations associated with a subset of tumors containing an expanded number of Paneth cells, a hallmark of deregulated Wnt signaling, and genes associated with more severe dysplasia included members of the FGF signaling cascade. Some 70 genes showed pairwise co-occurrence clustering into 38 sub-networks that may regulate tumor development

    TRANSFAC: a database on transcription factors and their DNA binding sites.

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    TRANSFAC is a database about eukaryotic transcription regulating DNA sequence elements and the transcription factors binding to and acting through them. This report summarizes the present status of this database and accompanying retrieval tools
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