198 research outputs found

    Electrical conductivity and gas-sensing properties of Mg-doped and undoped single-crystalline In2O3 thin films: Bulk vs. surface

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    This study aims to provide a better fundamental understanding of the gas-sensing mechanism of In2O3-based conductometric gas sensors. In contrast to typically used polycrystalline films, we study single crystalline In2O3 thin films grown by molecular beam epitaxy (MBE) as a model system with reduced complexity. Electrical conductance of these films essentially consists of two parallel contributions: the bulk of the film and the surface electron accumulation layer (SEAL). Both these contributions are varied to understand their effect on the sensor response. Conductance changes induced by UV illumination in air, which forces desorption of oxygen adatoms on the surface, give a measure of the sensor response and show that the sensor effect is only due to the SEAL contribution to overall conductance. Therefore, a strong sensitivity increase can be expected by reducing or eliminating the bulk conductivity in single crystalline films or the intra-grain conductivity in polycrystalline films. Gas-response measurements in ozone atmosphere test this approach for the real application

    Hodgkin's lymphoma in remission after first-line therapy: which patients need FDG-PET/CT for follow-up?

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    Background: The purpose of the study was to evaluate the impact of 2-[fluorine-18]fluoro-2-deoxy-D-glucose-positron emission tomography (FDG-PET)/computed tomography (CT) during follow-up of patients with Hodgkin's lymphoma. Patients and methods: Patients in complete remission or an unconfirmed complete remission after first-line therapy who received FDG-PET/CT during their follow-up were analyzed retrospectively. Confirmatory biopsy was mandatory in case of recurrence. Results: Overall, 134 patients were analyzed. Forty-two (31.3%) patients had a recurrence. The positive predictive value of FDG-PET/CT was 0.98. Single-factor analysis identified morphological residual mass [P = 0.0005, hazard ratio (HR) 3.4, 95% confidence interval (CI) 1.7-6.6] and symptoms (P 24 months). Conclusions: Asymptomatic patients without morphological residues and an early stage of disease do not need a routine FDG-PET/CT for follow-up. Asymptomatic patients with morphological residues should receive routine follow-up FDG-PET/CT for the first 24 months. Only patients with advanced initial stage do need a routine follow-up FDG-PET/CT beyond 24 month

    Strength of bacterial adhesion on nanostructured surfaces quantified by substrate morphometry

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    Microbial adhesion and the subsequent formation of resilient biofilms at surfaces are decisively influenced by substrate properties, such as the topography. To date, studies that quantitatively link surface topography and bacterial adhesion are scarce, as both are not straightforward to quantify. To fill this gap, surface morphometry combined with single-cell force spectroscopy was performed on surfaces with irregular topographies on the nano-scale. As surfaces, hydrophobized silicon wafers were used that were etched to exhibit surface structures in the same size range as the bacterial cell wall molecules. The surface structures were characterized by a detailed morphometric analysis based on Minkowski functionals revealing both qualitatively similar features and quantitatively different extensions. We find that as the size of the nanostructures increases, the adhesion forces decrease in a way that can be quantified by the area of the surface that is available for the tethering of cell wall molecules. In addition, we observe a bactericidal effect, which is more pronounced on substrates with taller structures but does not influence adhesion. Our results can be used for a targeted development of 3D-structured materials for/against bio-adhesion. Moreover, the morphometric analysis can serve as a future gold standard for characterizing a broad spectrum of material structures. © The Royal Society of Chemistry 2019

    Risk-adapted FDG-PET/CT-based follow-up in patients with diffuse large B-cell lymphoma after first-line therapy

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    Background: The purpose of this study was to evaluate the impact of 2-[fluorine-18]fluoro-2-deoxy-D-glucose-positron emission tomography/computed tomography (FDG-PET/CT) during follow-up of patients with diffuse large B-cell lymphoma (DLBCL) being in complete remission or unconfirmed complete remission after first-line therapy. Patients and methods: DLBCL patients receiving FDG-PET/CT during follow-up were analyzed retrospectively. Confirmatory biopsy was mandatory in cases of suspected disease recurrence. Results: Seventy-five patients were analyzed and 23 (30%) had disease recurrence. The positive predictive value (PPV) of FDG-PET/CT was 0.85. Patients >60 years [P = 0.036, hazard ratio (HR) = 3.82, 95% confidence interval (CI) 1.02-7.77] and patients with symptoms indicative of a relapse (P = 0.015; HR = 4.1; 95% CI 1.20-14.03) had a significantly higher risk for relapse. A risk score on the basis of signs of relapse, age >60 years, or a combination of these factors identified patients at high risk for recurrence (P = 0.041). Conclusions: FDG-PET/CT detects recurrent DLBCL after first-line therapy with high PPV. However, it should not be used routinely and if only in selected high-risk patients to reduce radiation burden and costs. On the basis of our retrospective data, FDG-PET/CT during follow-up is indicated for patients 60 years with and without clinical signs of relaps

    The conserved C-terminus of the PcrA/UvrD helicase interacts directly with RNA polymerase

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    Copyright: © 2013 Gwynn et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: This work was supported by a Wellcome Trust project grant to MD (Reference: 077368), an ERC starting grant to MD (Acronym: SM-DNA-REPAIR) and a BBSRC project grant to PM, NS and MD (Reference: BB/I003142/1). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD

    The ANKA-IR2 Nanoscope and Micro- and Nanospectroscopy Applications

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    We report on a newly developed and integrated microscopy and nanoscopy station at the ANKA-IR2 beamline. We further elucidate how vibrational near-field and microspectroscopy can give new insights in medical applications

    Nuclear fate of yeast snoRNA is determined by co-transcriptional Rnt1 cleavage

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    Small nucleolar RNA (snoRNA) are conserved and essential non-coding RNA that are transcribed by RNA Polymerase II (Pol II). Two snoRNA classes, formerly distinguished by their structure and ribonucleoprotein composition, act as guide RNA to target RNA such as ribosomal RNA, and thereby introduce specific modifications. We have studied the 5'end processing of individually transcribed snoRNA in S. cerevisiae to define their role in snoRNA biogenesis and functionality. Here we show that pre-snoRNA processing by the endonuclease Rnt1 occurs co-transcriptionally with removal of the m7G cap facilitating the formation of box C/D snoRNA. Failure of this process causes aberrant 3'end processing and mislocalization of snoRNA to the cytoplasm. Consequently, Rnt1-dependent 5'end processing of box C/D snoRNA is critical for snoRNA-dependent methylation of ribosomal RNA. Our results reveal that the 5'end processing of box C/D snoRNA defines their distinct pathway of maturation

    Researching shadow education: Methodological challenges and directions

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    Research on shadow education has considerably increased in volume and has helped to improve understanding of the scale, nature, and implications of the phenomenon. However, the field is still in its infancy. Literature on shadow education reflects confusion over terms and parameters, and data suffer from challenges in securing evidence from actors who may be unwilling or unable to respond to enquiries in a clear manner. Particular care is needed in cross-national and cross-cultural comparisons. Nevertheless, the trajectory of improvement in both conceptualisation and instrumentation gives ground for confidence that shadow education will be progressively better documented and better understood. © Education Research Institute, Seoul National University, Seoul, Korea 2010.published_or_final_versionSpringer Open Choice, 01 Dec 201
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