527 research outputs found

    Skin autofluorescence, a non-invasive biomarker for advanced glycation end products, is not related to the number of pregnancies

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    Highlights Skin autofluorescence (SAF) assesses subcutaneous accumulation of advanced glycation end products and has been shown to predict future cardiovascular disease and diabetes. A higher number of pregnancies was significantly associated with higher SAF, even after correction for relevant confounders like waist circumference, creatinine clearance, and diabetes status, but not after correction for age. Women with the highest SAF Z-score had a more unfavorable risk factor profile, with higher body mass index and waist circumference, higher blood pressure, lower high-density lipoprotein cholesterol, and higher triglyceride levels

    Nonlinear sigma model of a spin ladder containing a static single hole

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    In this letter we extend the nonlinear sigma model describing pure spin ladders with an arbitrary number of legs to the case of ladders containing a single static hole. A simple immediate application of this approach to classical ladders is worked out.Comment: 17 pages, 2 figure

    The IMO Reference Data Model: One Solution Fits Most!

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    In 2019, the International Maritime Organization (IMO) made it mandatory to support the electronic clearance of ships entering foreign ports. In preparation, the IMO Facilitation Committee started to develop a reference data model to harmonise the most important standards for ship clearance. The first version was published in 2020. The model is already extending into other areas of ship-port data exchanges and it is now increasingly seen as a tool to coordinate development of new electronic data exchange standards for ship operations. The lack of such coordination has, up until now, been a significant problem—much better coordination is essential in the relatively small and highly international market that shipping represents.acceptedVersio

    Long-term methylphenidate exposure and 24-hours blood pressure and left ventricular mass in adolescents and young adults with attention deficit hyperactivity disorder

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    Blood pressure; Echocardiography; MethylphenidatePresión arterial; Ecocardiografía; MetilfenidatoPressió arterial; Ecocardiografia; MetilfenidatYoung people with attention deficit hyperactivity disorder (ADHD) are now being treated with psychostimulant medication for longer than was previously the case and are increasingly likely to remain on methylphenidate into adolescence and adulthood. This study was designed to determine whether the long-term use of methylphenidate (MPH, immediate release or extended release) increases blood pressure and left ventricular mass (LVM) identified by echocardiography in adolescents and young adults with ADHD aged 12-25 years. In a five-site cross-sectional design two groups were compared for 24- hour blood pressure and heart rate (HR) registrations and LVM: 1) adolescents and young adults with ADHD who had been treated with MPH for > 2 years (N=162, age mean (SD) 15.6 (3.0)), and 2) adolescents and young adults with ADHD who had never been treated with methylphenidate (N=71, age mean 17.4 (4.2)). The analyses were controlled for propensity scores derived from age, sex, height, weight, and 19 relevant background variables. A blood pressure indicative of hypertension (>95th percentile) was observed in 12.2% (95% confidence interval 7.3 – 18.9%) of the participants in the MPH treated group and in 9.6% (95%CI 3.2 – 21.0%) of the MPH naïve group, with overlapping intervals. The 24-hour recorded systolic blood pressure (SBP) and HR were significantly higher during daytime in medicated individuals with ADHD than in those with unmedicated ADHD, but were similar in both groups during the night. 24-hour diastolic blood pressure (DBP) did not differ between both groups during either daytime or at night. LVM, corrected for body-surface area (LVMBSA), also did not differ between the two groups (p=0.20, controlling for confounders). Further, MPH daily dose and duration of treatment were unrelated to LVMBSA, SBP, and DBP. Long-term MPH use in adolescents and young adults with ADHD is associated with small but significant increases of SBP and HR during daytime. Given the current sample size, the proportions of hypertension do not differ significantly between MPH treated and MPH-naïve individuals with ADHD. Future studies with larger samples, longer treatment duration, and/or with within-subject designs are necessary. The results do, however, further support recommendations that highlight the importance of monitoring blood pressure and HR during MPH treatment.This work was supported by the European Union 7th framework grant “Attention Deficit Hyperactivity Disorder Drugs Use Chronic Effects” (ADDUCE, grant no. 260576). The funder had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results. Any views expressed are those of the authors and not necessarily those of the funder

    Anomalous mirror symmetry breaking in a model insulating cuprate Sr₂CuO₂Cl₂

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    Understanding the complex phase diagram of cuprate superconductors is an outstanding challenge. The most actively studied questions surround the nature of the pseudogap and strange metal states and their relationship to superconductivity. In contrast, there is general agreement that the low energy physics of the Mott insulating parent state is well captured by a two-dimensional spin S = 1/2 antiferromagnetic (AFM) Heisenberg model. However, recent observations of a large thermal Hall conductivity in several parent cuprates appear to defy this simple model and suggest proximity to a magneto-chiral state that breaks all mirror planes perpendicular to the CuO₂ layers. Here we use optical second harmonic generation to directly resolve the point group symmetries of the model parent cuprate Sr₂CuO₂Cl₂. We report evidence of an order parameter Φ that breaks all perpendicular mirror planes and is consistent with a magneto-chiral state in zero magnetic field. Although Φ is clearly coupled to the AFM order parameter, we are unable to realize its time-reversed partner (−Φ) by thermal cycling through the AFM transition temperature (TN ≈ 260 K) or by sampling different spatial locations. This suggests that Φ onsets above TN and may be relevant to the mechanism of pseudogap formation

    Powerlaw optical conductivity with a constant phase angle in high Tc superconductors

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    In certain materials with strong electron correlations a quantum phase transition (QPT) at zero temperature can occur, in the proximity of which a quantum critical state of matter has been anticipated. This possibility has recently attracted much attention because the response of such a state of matter is expected to follow universal patterns defined by the quantum mechanical nature of the fluctuations. Forementioned universality manifests itself through power-law behaviours of the response functions. Candidates are found both in heavy fermion systems and in the cuprate high Tc superconductors. Although there are indications for quantum criticality in the cuprate superconductors, the reality and the physical nature of such a QPT are still under debate. Here we identify a universal behaviour of the phase angle of the frequency dependent conductivity that is characteristic of the quantum critical region. We demonstrate that the experimentally measured phase angle agrees precisely with the exponent of the optical conductivity. This points towards a QPT in the cuprates close to optimal doping, although of an unconventional kind.Comment: pdf format, 9 pages, 4 color figures include

    Understanding the impact of tuberous sclerosis complex:development and validation of the TSC-PROM

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    BACKGROUND: Tuberous sclerosis complex (TSC) is a rare and complex genetic disorder, associated with tumor growth in various organ systems, epilepsy, and a range of neuropsychiatric manifestations including intellectual disability. With improving patient-centered care and targeted therapies, patient-reported outcome measures (PROMs) are needed to measure the impact of TSC manifestations on daily functioning. The aim of this study was to develop a TSC-specific PROM for adults that captures the impact of TSC on physical functions, mental functions, activity and participation, and the social support individuals with TSC receive, called the TSC-PROM. METHODS: COSMIN methodology was used to develop a self-reported and proxy-reported version. Development and validation consisted of the following studies: PROM development, content validity, structural validity, internal consistency, and construct validity. The International Classification of Functioning and Disability was used as a framework. Content validity was examined by a multidisciplinary expert group and cognitive interview study. Structural and construct validity, and internal consistency were examined in a large cohort, using confirmatory factor analysis, hypotheses testing, and Cronbach's alpha. RESULTS: The study resulted in an 82-item self version and 75-item proxy version of the TSC-PROM with four subscales (physical functions 18 and 19 items, mental functions 37 and 28 items, activities and participation 13 and 14 items, social support 13 items, for self version and proxy version respectively). Sufficient results were found for structural validity with sufficient unidimensionality for each subscale. With regard to construct validity, 82% of the hypotheses were met for the self version and 59% for the proxy version. The PROM showed good internal consistency (Cronbach's alpha 0.78-0.97). CONCLUSIONS: We developed a PROM for adults with TSC, named TSC-PROM, showing sufficient evidence for reliability and validity that can be used in clinical and research settings to systematically gain insight into their experiences. It is the first PROM in TSC that addresses the impact of specific TSC manifestations on functioning, providing a valuable, patient-centered addition to the current clinical outcomes.</p

    Spin-1/2 frustrated antiferromagnet on a spatially anisotopic square lattice: contribution of exact diagonalizations

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    The phase diagram of a spin-1/2 JJJ2J-J'-J_2 model is investigated by means of exact diagonalizations on finite samples. This model is a generalization of the J1J2J_1-J_2 model on the square lattice with two different nearest-neighbor couplings J,JJ,J' and may be also viewed as an array of coupled Heisenberg chains. The results suggest that the resonnating valence bond state predicted by Nersesyan and Tsvelik [Phys. Rev. B {\bf 67}, 024422 (2003)] for J2=0.5JJJ_2=0.5J' \ll J is realized and extends beyond the limit of small interchain coupling along a curve nearly coincident with the line where the energy per spin is maximum. This line is likely bordered on both side by a columnar dimer long range order. This columnar order could extends for JJJ'\to J which correspond to the J1J2J_1-J_2 model.Comment: 14 pages, 21 figures, final versio
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