1,288 research outputs found

    Androgen receptor complexes probe DNA for recognition sequences by short random interactions

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    Owing to the tremendous progress in microscopic imaging of fluorescently labeled proteins in living cells, the insight into the highly dynamic behavior of transcription factors has rapidly increased over the past decade. However, a consistent quantitative scheme of their action is still lacking. Using the androgen receptor (AR) as a model system, we combined three different fluorescence microscopy assays: single-molecule microscopy, photobleaching and correlation spectroscopy, to provide a quantitative model of the action of this transcription factor. This approach enabled us to distinguish two types of AR-DNA binding: very brief interactions, in the order of a few hundred milliseconds, and hormone-induced longer-lasting interactions, with a characteristic binding time of several seconds. In addition, freely mobile ARs were slowed down in the presence of hormone, suggesting the formation of large AR-co-regulator complexes in the nucleoplasm upon hormone activation. Our data suggest a model in which mobile hormone-induced complexes of transcription factors and co-regulators probe DNA by briefly binding at random sites, only forming relatively stable transcription initiation complexes when bound to specific recognition sequences

    The HERMES Back Drift Chambers

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    The tracking system of the HERMES spectrometer behind the bending magnet consists of two pairs of large planar 6-plane drift chambers. The design and performance of these chambers is described. This description comprises details on the mechanical and electronical design, information about the gas mixture used and its properties, results on alignment, calibration, resolution, and efficiencies, and a discussion of the experience gained through the first three years of operation.Comment: 21 pages, LaTex, 16 figures include

    A universal anti-Xa assay for rivaroxaban, apixaban, and edoxaban measurements: method validation, diagnostic accuracy and external validation.

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    A universal anti-Xa assay for the determination of rivaroxaban, apixaban and edoxaban drug concentrations would simplify laboratory procedures and facilitate widespread implementation. Following two pilot studies analysing spiked samples and material from 698 patients, we conducted a prospective multicentre cross-sectional study, including 867 patients treated with rivaroxaban, apixaban or edoxaban in clinical practice to comprehensively evaluate a simple, readily available anti-Xa assay that would accurately measure drug concentrations and correctly predict relevant levels in clinical practice. Anti-Xa activity was measured by an assay calibrated with low-molecular-weight heparin (LMWH) in addition to ultra-high performance liquid chromatography-tandem mass spectrometry (LC-MS/MS). As an external validation, LMWH-calibrated anti-Xa activity was also determined in nine external laboratories. The LMWH-calibrated anti-Xa activity correlated strongly with rivaroxaban, apixaban or edoxaban drug levels [r <sub>s</sub> = 0·98, 95% confidence interval (CI) 0·98-0·98]. The sensitivity for the clinically relevant cut-off levels of 30, 50 and 100 µg/l was 96·2% (95% CI 94·4-97·4), 96·4% (95% CI 94·4-97·7) and 96·7% (95% CI 94·3-98·1) respectively. Concordant results were obtained in the external validation study. In conclusion, a universal, LMWH-calibrated anti-Xa assay accurately measured rivaroxaban, apixaban and edoxaban concentrations and correctly predicted relevant drug concentrations in clinical practice

    Body fat measurement among Singaporean Chinese, Malays and Indians: a comparative study using a four-compartment model and different two-compartment models

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    This cross-sectional study compared body fat percentage (BF€obtained from a four-compartment (4C) model with BF␏rom hydrometry (using 2H2O), dual-energy X-ray absorptiometry (DXA) and densitometry among the three main ethnic groups (Chinese, Malays and Indians) in Singapore, and determined the suitability of two-compartment (2C) models as surrogate methods for assessing BFmong different ethnic groups. A total of 291 subjects (108 Chinese, seventy-six Malays, 107 Indians) were selected to ensure an adequate representation of age range (18-75 years) and BMI range (16-40 kg/m2) of the general adult population, with almost equal numbers from each gender group. Body weight was measured, together with body height, total body water by 2H2O dilution, densitometry with Bodpod? and bone mineral content with Hologic? QDR-4500. BF␖easurements with a 4C model for the subgroups were: Chinese females 33?5 (SD 7?5), CHINESE MALES 24?4 (sd 6?1), Malay females 37?8 (sd 6?3), Malay males 26?0 (sd 7?6), Indian females 38?2 (sd 7?0), Indian males 28?1 (sd 5?5). Differences between BF␖easured by the 4C and 2C models (hydrometry, DXA and densitometry) were found, with underestimation of BF␒n all the ethnic-gender groups by DXA of 2?1-4?2 BFnd by densitometry of 0?5-3?2 BFŽ On a group level, the differences in BF␋etween the 4C model and 2H2O were the lowest (0?0-1?4 BF␒n the different groups), while differences between the 4C model and DXA were the highest. Differences between the 4C model and 2H2O and between the 4C model and DXA were positively correlated with the 4C model, water fraction (fwater) of fat-free mass (FFM) and the mineral fraction (fmineral) of FFM, and negatively correlated with density of the FFM (DFFM), while the difference between 4C model and densitometry correlated with these variables negatively and positively respectively (i.e. the correlations were opposite). The largest contributors to the observed differences were fwater and DFFM. When validated against the reference 4C model, 2C models were found to be unsuitable for accurate measurements of BFt the individual level, owing to the high errors and violation of assumptions of constant hydration of FFM and DFFM among the ethnic groups. On a group level, the best 2C model for measuring BFmong Singaporeans was found to be 2H2O

    Imaging in diagnosis, outcome prediction and monitoring of large vessel vasculitis : a systematic literature review and meta-analysis informing the EULAR recommendations

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    Objectives: To perform a systematic literature review on imaging techniques for diagnosis, outcome prediction and disease monitoring in large vessel vasculitis (LVV) informing the European League Against Rheumatism recommendations for imaging in LVV. Methods: Systematic literature review (until 10 March 2017) of diagnostic and prognostic studies enrolling >20 patients and investigating ultrasound, MRI, CT or positron emission tomography (PET) in patients with suspected and/or established primary LVV. Meta-analyses were conducted, whenever possible, obtaining pooled estimates for sensitivity and specificity by fitting random effects models. Results: Forty-three studies were included (39 on giant cell arteritis (GCA), 4 on Takayasu arteritis (TAK)). Ultrasound (‘halo’ sign) at temporal arteries (8 studies, 605 patients) and MRI of cranial arteries (6 studies, 509 patients) yielded pooled sensitivities of 77% (95% CI 62% to 87%) and 73% (95% CI 57% to 85%), respectively, compared with a clinical diagnosis of GCA. Corresponding specificities were 96% (95% CI 85% to 99%) and 88% (95% CI 81% to 92%). Two studies (93 patients) investigating PET for GCA diagnosis reported sensitivities of 67%–77% and specificities of 66%–100% as compared with clinical diagnosis or temporal artery biopsy. In TAK, one study each evaluated the role of magnetic resonance angiography and CT angiography for diagnostic purposes revealing both a sensitivity and specificity of 100%. Studies on outcome prediction and monitoring disease activity/damage were limited and mainly descriptive. Conclusions: Ultrasound and MRI provide a high diagnostic value for cranial GCA. More data on the role of imaging for diagnosis of extracranial large vessel GCA and TAK, as well as for outcome prediction and monitoring in LVV are warranted

    Coverage-controlled polymorphism of H-bonded networks on Au(111)

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    We report on the self-assembly of a conformational flexible organic compound on Au(111) using scanning tunneling microscopy and low-energy electron diffraction measurements. We observed different conformers of the compound upon adsorption on the reconstructed Au(111) surface. Increasing the molecular coverage enhanced the lateral pressure, that is, parallel to the surface, favoring a coverage-controlled transition from a supramolecular network displaying only one molecular organization, into a polymorphic array with two coexisting arrangements. Our results give insights into the role of substrate-induced conformational changes on the formation of polymorphic supramolecular networks

    Fokker-Planck equations and density of states in disordered quantum wires

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    We propose a general scheme to construct scaling equations for the density of states in disordered quantum wires for all ten pure Cartan symmetry classes. The anomalous behavior of the density of states near the Fermi level for the three chiral and four Bogoliubov-de Gennes universality classes is analysed in detail by means of a mapping to a scaling equation for the reflection from a quantum wire in the presence of an imaginary potential.Comment: 10 pages, 5 figures, revised versio

    Tumor immunosurveillance in human cancers

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    Until now, the anatomic extent of tumor (TNM classification) has been by far the most important factor to predict the prognosis of colorectal cancer patients. However, in recent years, data collected from large cohorts of human cancers demonstrated that the immune contexture of the primary tumors is an essential prognostic factor for patients’ disease-free and overall survival. Tumoral and immunological markers predicted by systems biology methods are involved in the shaping of an efficient immune reaction and can serve as targets for novel therapeutic approaches. Global analysis of tumor microenvironment showed that the nature, the functional orientation, the density, and the location of adaptive immune cells within distinct tumor regions influence the risk of relapse events. The density and the immune cell location within the tumor have a prognostic value that is superior to the TNM classification, and tumor invasion is statistically dependent on the host-immune reaction. Thus, the strength of the immune reaction could advance our understanding of cancer evolution and have important consequences in clinical practice

    Naked Singularity Formation In f(R) Gravity

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    We study the gravitational collapse of a star with barotropic equation of state p=wρp=w\rho in the context of f(R)f({\mathcal R}) theories of gravity. Utilizing the metric formalism, we rewrite the field equations as those of Brans-Dicke theory with vanishing coupling parameter. By choosing the functionality of Ricci scalar as f(R)=αRmf({\mathcal R})=\alpha{\mathcal R}^{m}, we show that for an appropriate initial value of the energy density, if α\alpha and mm satisfy certain conditions, the resulting singularity would be naked, violating the cosmic censorship conjecture. These conditions are the ratio of the mass function to the area radius of the collapsing ball, negativity of the effective pressure, and the time behavior of the Kretschmann scalar. Also, as long as parameter α\alpha obeys certain conditions, the satisfaction of the weak energy condition is guaranteed by the collapsing configuration.Comment: 15 pages, 4 figures, to appear in GR

    Imaging in diagnosis, monitoring and outcome prediction of large vessel vasculitis: a systematic literature review and meta-analysis informing the 2023 update of the EULAR recommendations

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    Objectives To update the evidence on imaging for diagnosis, monitoring and outcome prediction in large vessel vasculitis (LVV) to inform the 2023 update of the European Alliance of Associations for Rheumatology recommendations on imaging in LVV. Methods Systematic literature review (SLR) (2017–2022) including prospective cohort and cross-sectional studies (>20 participants) on diagnostic, monitoring, outcome prediction and technical aspects of LVV imaging. Diagnostic accuracy data were meta-analysed in combination with data from an earlier (2017) SLR. Results The update retrieved 38 studies, giving a total of 81 studies when combined with the 2017 SLR. For giant cell arteritis (GCA), and taking clinical diagnosis as a reference standard, low risk of bias (RoB) studies yielded pooled sensitivities and specificities (95% CI) of 88% (82% to 92%) and 96% (95% CI 86% to 99%) for ultrasound (n=8 studies), 81% (95% CI 71% to 89%) and 98% (95% CI 89% to 100%) for MRI (n=3) and 76% (95% CI 67% to 83%) and 95% (95% CI 71% to 99%) for fluorodeoxyglucose positron emission tomography (FDG-PET, n=4), respectively. Compared with studies assessing cranial arteries only, low RoB studies with ultrasound assessing both cranial and extracranial arteries revealed a higher sensitivity (93% (95% CI 88% to 96%) vs 80% (95% CI 71% to 87%)) with comparable specificity (94% (95% CI 83% to 98%) vs 97% (95% CI 71% to 100%)). No new studies on diagnostic imaging for Takayasu arteritis (TAK) were found. Some monitoring studies in GCA or TAK reported associations of imaging with clinical signs of inflammation. No evidence was found to determine whether imaging severity might predict worse clinical outcomes. Conclusion Ultrasound, MRI and FDG-PET revealed a good performance for the diagnosis of GCA. Cranial and extracranial vascular ultrasound had a higher pooled sensitivity with similar specificity compared with limited cranial ultrasound
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