36 research outputs found

    Equation of state and phonon frequency calculations of diamond at high pressures

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    The pressure-volume relationship and the zone-center optical phonon frequency of cubic diamond at pressures up to 600 GPa have been calculated based on Density Functional Theory within the Local Density Approximation and the Generalized Gradient Approximation. Three different approaches, viz. a pseudopotential method applied in the basis of plane waves, an all-electron method relying on Augmented Plane Waves plus Local Orbitals, and an intermediate approach implemented in the basis of Projector Augmented Waves have been used. All these methods and approximations yield consistent results for the pressure derivative of the bulk modulus and the volume dependence of the mode Grueneisen parameter of diamond. The results are at variance with recent precise measurements up to 140 GPa. Possible implications for the experimental pressure determination based on the ruby luminescence method are discussed.Comment: 10 pages, 6 figure

    Gaussian Tunneling Model of c-Axis Twist Josephson Junctions

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    We calculate the critical current density JcJJ^J_c for c-axis Josephson tunneling between identical high temperature superconductors twisted an angle ϕ0\phi_0 about the c-axis. We model the tunneling matrix element squared as a Gaussian in the change of wavevector q parallel to the junction, <t(q)2>exp(q2a2/2π2σ2)<|t({\bf q})|^2>\propto\exp(-{\bf q}^2a^2/2\pi^2\sigma^2). The JcJ(ϕ0)/JcJ(0)J^J_c(\phi_0)/J^J_c(0) obtained for the s- and extended-s-wave order parameters (OP's) are consistent with the Bi2_2Sr2_2CaCu2_2O8+δ_{8+\delta} data of Li {\it et al.}, but only for strongly incoherent tunneling, σ20.25\sigma^2\ge0.25. A dx2y2d_{x^2-y^2}-wave OP is always inconsistent with the data. In addition, we show that the apparent conventional sum rule violation observed by Basov et al. might be understandable in terms of incoherent c-axis tunneling, provided that the OP is not dx2y2d_{x^2-y^2}-wave.Comment: 6 pages, 6 figure

    The Danish High Risk and Resilience Study-VIA 11: Study Protocol for the First Follow-Up of the VIA 7 Cohort -522 Children Born to Parents With Schizophrenia Spectrum Disorders or Bipolar Disorder and Controls Being Re-examined for the First Time at Age 11.

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    Introduction: Offspring of parents with severe mental illness have an increased risk of developing mental illnesses themselves. Familial high risk cohorts give a unique opportunity for studying the development over time, both the illness that the individual is predisposed for and any other diagnoses. These studies can also increase our knowledge of etiology of severe mental illness and provide knowledge about the underlying mechanisms before illness develops. Interventions targeting this group are often proposed due to the potential possibility of prevention, but evidence about timing and content is lacking. Method: A large, representative cohort of 522 7-year old children born to parents with schizophrenia, bipolar disorder or controls was established based on Danish registers. A comprehensive baseline assessment including neurocognition, motor functioning, psychopathology, home environment, sociodemographic data, and genetic information was conducted from January 1, 2013 to January 31, 2016. This study is the first follow-up of the cohort, carried out when the children turn 11 years of age. By assessing the cohort at this age, we will evaluate the children twice before puberty. All instruments have been selected with a longitudinal perspective and most of them are identical to those used at inclusion into the study at age 7. A diagnostic interview, motor tests, and a large cognitive battery are conducted along with home visits and information from teachers. This time we examine the children's brains by magnetic resonance scans and electroencephalograms. Measures of physical activity and sleep are captured by a chip placed on the body, while we obtain biological assays by collecting blood samples from the children. Discussion: Findings from the VIA 7 study revealed large variations across domains between children born to parents with schizophrenia, bipolar and controls, respectively. This study will further determine whether the children at familial risk reveal delayed developmental courses, but catch up at age 11, or whether the discrepancies between the groups have grown even larger. We will compare subgroups within each of the familial high risk groups in order to investigate aspects of resilience. Data on brain structure and physical parameters will add a neurobiological dimension to the study

    Dynamic protein methylation in chromatin biology

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    Post-translational modification of chromatin is emerging as an increasingly important regulator of chromosomal processes. In particular, histone lysine and arginine methylation play important roles in regulating transcription, maintaining genomic integrity, and contributing to epigenetic memory. Recently, the use of new approaches to analyse histone methylation, the generation of genetic model systems, and the ability to interrogate genome wide histone modification profiles has aided in defining how histone methylation contributes to these processes. Here we focus on the recent advances in our understanding of the histone methylation system and examine how dynamic histone methylation contributes to normal cellular function in mammals

    Periodontitis and cardiovascular diseases. Consensus report

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    Background: In Europe cardiovascular disease (CVD) is responsible for 3.9 million deaths (45% of deaths), being ischaemic heart disease, stroke, hypertension (leading to heart failure) the major cause of these CVD related deaths. Periodontitis is also a chronic non‐communicable disease (NCD) with a high prevalence, being severe periodontitis, affecting 11.2% of the world&apos;s population, the sixth most common human disease. Material and Methods: There is now a significant body of evidence to support independent associations between severe periodontitis and several NCDs, in particular CVD. In 2012 a joint workshop was held between the European Federation of Periodontology (EFP) and the American Academy of Periodontology to review the literature relating periodontitis and systemic diseases, including CVD. In the last five years important new scientific information has emerged providing important emerging evidence to support these associations. Results and Conclusions: The present review reports the proceedings of the workshop jointly organised by the EFP and the World Heart Federation (WHF), which has updated the existing epidemiological evidence for significant associations between periodontitis and CVD, the mechanistic links and the impact of periodontal therapy on cardiovascular and surrogate outcomes. This review has also focused on the potential risk and complications of periodontal therapy in patients on anti thrombotic therapy and has made recommendations for dentists, physicians and for patients visiting both the dental and medical practices. Copyright: © 2020 The Author(s). This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International License (CC-BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. See http://creativecommons.org/licenses/by/4.0/

    Hair cortisol concentrations and daily life stress in 7-year-old children at familial high-risk of schizophrenia or bipolar disorder. The Danish High Risk and Resilience Study - VIA 7.

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    Dysregulation of the HPA-axis, perceived stress and interpersonal trauma are associated with an elevated risk for schizophrenia and bipolar disorder. Being at familial high-risk of these two mental disorders also constitutes an increased risk. In this study, we aimed to investigate hair cortisol concentrations and perceived stress among 7-year-old children at familial high-risk of schizophrenia (FHR-SZ), bipolar disorder (FHR-BP), and population-based controls (controls). A total of 515 children (mean age 7.8, SD 0.2) from baseline assessment of the Danish High Risk and Resilience Study - VIA 7 participated in this study. Hair cortisol concentrations were analyzed among 322 children (FHR-SZ; N = 111, FHR-BP; N = 82, controls; N = 129). Perceived stress was assessed with the Daily Life Stressor Scale including 512 children (FHR-SZ; N = 195, FHR-BP; N = 118, controls; N = 199). Interpersonal trauma was measured with face-to-face interviews. Seven-year-old children at FHR-SZ or FHR-BP did not have a higher level of hair cortisol concentrations compared with controls (FHR-SZ: mean: 5.10, 95%CI 3.69-6.52; FHR-BP: mean: 5.01, 95%CI 3.27-6.72; controls: mean: 4.51, 95%CI 3.61-5.40; p = 0.77). Self-reported perceived stress was higher among children at FHR-SZ and FHR-BP compared with controls (FHR-SZ: mean: 12.09, 95%CI 10.99-13.19; FHR-BP: mean: 10.69, 95%CI 9.38-11.99; controls: mean: 8.90, 95%CI 8.13-9.68; p &lt; 0.001). There was no significant association between hair cortisol concentrations and perceived stress (p = 0.84). Exploratory analyses revealed that interpersonal trauma exposure was neither associated with elevated hair cortisol nor perceived stress. Children at FHR-SZ and FHR-BP did not exhibit higher levels of hair cortisol concentrations at age 7, while both FHR-groups had higher level of self-reported perceived stress compared with controls. Early attention to stress in children at FHR is crucial and these vulnerabilities should be targeted in future interventions studies

    Sustained Attention and Interference Control Among 7-Year-Old Children With a Familial High Risk of Schizophrenia or Bipolar Disorder-A Nationwide Observational Cohort Study.

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    Given the partially shared genetic liability between schizophrenia and bipolar disorder, we aimed to assess whether 7-year-old children with a familial high risk of schizophrenia or bipolar disorder display specific deficits of sustained attention and interference control compared with each other and with control children. An observational cohort was identified through Danish registries and consisted of 522 children 7 years of age with no, one, or two parents with a diagnosis of schizophrenia or bipolar disorder. Control subjects were matched based on age, sex, and municipality. Sustained attention and interference control were assessed using Conners' Continuous Performance Test II and a modified Eriksen flanker task. Assessors were blinded to group membership of participants. The effect of higher genetic loading was not considered in the statistical models owing to low numbers. At 7 years of age, children with a familial high risk of schizophrenia displayed deficits of sustained attention and subtle deficits in interference control compared with control children and children with a familial high risk of bipolar disorder. Children with a familial high risk of bipolar disorder displayed similar abilities of sustained attention and interference control as control children except in terms of a lower accuracy. Our findings suggest distinct neurodevelopmental characteristics in middle childhood of sustained attention and interference control for children of parents with schizophrenia or bipolar disorder

    Odor identification in 7-year-old children at familial high risk of schizophrenia or bipolar disorder - the Danish high risk and resilience study VIA 7.

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    Odor identification deficits occur in individuals with schizophrenia and their unaffected first-degree relatives, while deficits are less pronounced in individuals with bipolar disorder. We hypothesized that children at familial high-risk for schizophrenia (FHR-SZ) show odor identification deficits compared to population-based controls and that children at familial high-risk for bipolar disorder (FHR-BP) perform intermediate. Odor identification was assessed at age 7 in 184 children with FHR-SZ, 106 children with FHR-BP, and 186 population-based controls with the Brief Smell Identification Test. Dimensional and predefined categorical outcomes were used in the analyses. Potential relationships with psychopathological, cognitive, and home environmental variables were conducted using hierarchical and logistic multiple regression analyses. ANOVA revealed no between-group differences in odor identification. Using the recommended cut-off (below 5), we found a significantly greater proportion of boys at FHR-SZ than population-based boys with an abnormal odor identification (p = .013). However, a supplementary analysis using a Danish-based cut-off (below 4) did not support this. All children showed significant, positive associations of odor identification with female gender, social responsiveness, and verbal working memory. Lower social responsiveness predicted abnormal odor identification in boys at FHR-SZ, only using the recommended cut-off. Odor identification efficacy and risk status appear independent in this early developmental phase. Using the recommended threshold, abnormal odor identification is more frequent in young boys at FHR-SZ than in population-based boys and is linked to lower social responsiveness. The validity of these results is questioned by non-significant differences in the rates when using an exploratory Danish-based threshold
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