1,325 research outputs found

    Self-diffusion and Cooperative Diffusion in Semidilute Polymer Solutions as measured by Fluorescence Correlation Spectroscopy

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    We present a comprehensive investigation of polymer diffusion in the semidilute regime by fluorescence correlation spectroscopy (FCS) and dynamic light scattering (DLS). Using single-labeled polystyrene chains, FCS leads to the self-diffusion coefficient while DLS gives the cooperative diffusion coefficient for exactly the same molecular weights and concentrations. Using FCS we observe a new fast mode in the semidilute entangled concentration regime beyond the slower mode which is due to self-diffusion. Comparison of FCS data with data obtained by DLS on the same polymers shows that the second mode observed in FCS is identical to the cooperative diffusion coefficient measured with DLS. An in-depth analysis and a comparison with current theoretical models demonstrates that the new cooperative mode observed in FCS is due to the effective long-range interaction of the chains through the transient entanglement network

    Glyphosate and AMPA levels in human urine samples and their correlation with food consumption: results of the cross-sectional KarMeN study in Germany

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    Glyphosate (N-[phosphonomethyl]-glycine) is the most widely used herbicide worldwide. Due to health concerns about glyphosate exposure, its continued use is controversially discussed. Biomonitoring is an important tool in safety evaluation and this study aimed to determine exposure to glyphosate and its metabolite AMPA, in association with food consumption data, in participants of the cross-sectional KarMeN study (Germany). Glyphosate and AMPA levels were measured in 24-h urine samples from study participants (n = 301). For safety evaluation, the intake of glyphosate and AMPA was calculated based on urinary concentrations and checked against the EU acceptable daily intake (ADI) value for glyphosate. Urinary excretion of glyphosate and/or AMPA was correlated with food consumption data. 8.3% of the participants (n = 25) exhibited quantifiable concentrations (> 0.2 μg/L) of glyphosate and/or AMPA in their urine. In 66.5% of the samples, neither glyphosate (< 0.05 μg/L) nor AMPA (< 0.09 μg/L) was detected. The remaining subjects (n = 76) showed traces of glyphosate and/or AMPA. The calculated glyphosate and/or AMPA intake was far below the ADI of glyphosate. Significant, positive associations between urinary glyphosate excretion and consumption of pulses, or urinary AMPA excretion and mushroom intake were observed. Despite the widespread use of glyphosate, the exposure of the KarMeN population to glyphosate and AMPA was found to be very low. Based on the current risk assessment of glyphosate by EFSA, such exposure levels are not expected to pose any risk to human health. The detected associations with consuming certain foods are in line with reports on glyphosate and AMPA residues in food

    Protection against ultraviolet radiation by commercial summer clothing: need for standardised testing and labelling

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    BACKGROUND: The use of clothing as a means of sun protection has been recommended in recent education campaigns. Contrary to popular opinion, however, some fabrics provide insufficient ultraviolet (UV) protection. MATERIAL AND METHODS: We investigated 236 apparel textiles of the spring/summer collections 2000 and 2001. In accordance with the forthcoming European standard the UV protection factor (UPF) of the fabrics was determined spectrophotometrically. RESULTS: Seventy-eight (33%) fabrics had UPF < 15, 45 (19%) had UPF = or > 15 and < 30, and 113 (48%) had UPF = or > 30 (30+). More than 70% of the wool, polyester, and fabric blends, and only less than 30% of the cotton, linen, and viscose fabrics had UPF values of 30+. Fabrics with black, navy-blue, white, green, or beige colours provided most frequently UPF values of 30+. CONCLUSIONS: It is difficult for the sun-aware consumer to choose the 'right' garment, with a third of summer clothing providing insufficient UV protection and only half of the fabrics having UPF 30+, the UPF recommended by the European standard. Therefore, apparel summer fabrics should be measured and labelled in accordance with a standard document

    Cosmopolitan conservation: the multi-scalar contributions of urban green infrastructure to biodiversity protection [Letter]

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    Urbanization is a leading cause of biodiversity loss globally. Expanding cities alter regional ecological processes by consuming habitat and modifying biogeochemical and energetic flows. Densifying cities often lose valuable intra-urban green spaces. Despite these negative impacts, novel urban ecosystems can harbor high biodiversity and provide vital ecosystem services for urban residents. Recognizing the benefits of urban ecosystems, cities across the globe are increasingly planning for urban green infrastructure (UGI). UGI as a planning concept can transform how cities integrate biodiversity into urbanized landscapes at multiple scales and contribute to conservation goals. Full operationalization of UGI concepts can also reduce urban energy and resource demands via substituting polluting technologies by UGI, further contributing to the global conservation agenda. Realizing the potential contributions of UGI to local, regional, and global conservation goals requires addressing four inter-dependent challenges: (1) expanding social-ecological-systems thinking to include connections between complex social, ecological, and technological systems (SETS), (2) explicitly addressing multi-level governance challenges, (3) adapting SETS approaches to understand the contextual and biocultural factors shaping relationships between UGI and other causal processes in cities that shape biodiversity, and (4) operationalizing UGI systems through robust modeling and design approaches. By transforming UGI policy and research through SETS approaches to explicitly integrate biodiversity we can support global conservation challenges while improving human wellbeing in cities and beyond

    Toward Good In Vitro Reporting Standards

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    A good experiment reported badly is worthless. Meaningful contributions to the body of science are made by sharing the full methodology and results so that they can be evaluated and reproduced by peers. Erroneous and incomplete reporting does not do justice to the resources spent on conducting the experiment and the time peers spend reading the article. In theory peer-review should ensure adequate reporting – in practice it does not. Many areas have developed reporting standards and checklists to support the adequate reporting of scientific efforts, but in vitro research still has no generally accepted criteria. It is characterized by a “Wild West” or “anything goes” attitude. Such a culture may undermine trust in the reproducibility of animal-free methods, and thus parallel the “reproducibility crisis” discussed for other life science fields. The increasing data retrieval needs of computational approaches (in extreme as “big data” and artificial intelligence) makes reporting quality even more important so that the scientific community can take full advantage of the results. The first priority of reporting standards is to ensure the completeness and transparency of information provided (data focus). The second tier is a quality of data display that makes information digestible and easy to grasp, compare and further analyze (information focus). This article summarizes a series of initiatives geared towards improving the quality of in vitro work and its reporting. This shall ultimately lead to Good In Vitro Reporting Standards (GIVReSt)

    CHIASM-Net: Artificial Intelligence-Based Direct Identification of Chiasmal Abnormalities in Albinism

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    Purpose: Albinism is a congenital disorder affecting pigmentation levels, structure, and function of the visual system. The identification of anatomical changes typical for people with albinism (PWA), such as optic chiasm malformations, could become an important component of diagnostics. Here, we tested an application of convolutional neural networks (CNNs) for this purpose.Methods: We established and evaluated a CNN, referred to as CHIASM-Net, for the detection of chiasmal malformations from anatomic magnetic resonance (MR) images of the brain. CHIASM-Net, composed of encoding and classification modules, was developed using MR images of controls (n = 1708) and PWA (n = 32). Evaluation involved 8-fold cross validation involving accuracy, precision, recall, and F1-score metrics and was performed on a subset of controls and PWA samples excluded from the training. In addition to quantitative metrics, we used Explainable AI (XAI) methods that granted insights into factors driving the predictions of CHIASM-Net.Results: The results for the scenario indicated an accuracy of 85 ± 14%, precision of 90 ± 14% and recall of 81 ± 18%. XAI methods revealed that the predictions of CHIASM-Net are driven by optic-chiasm white matter and by the optic tracts.Conclusions: CHIASM-Net was demonstrated to use relevant regions of the optic chiasm for albinism detection from magnetic resonance imaging (MRI) brain anatomies. This indicates the strong potential of CNN-based approaches for visual pathway analysis and ultimately diagnostics

    Guideline adherence and patient satisfaction in the treatment of inflammatory bowel disorders – an evaluation study

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    Background: Crohn's disease (CD) and ulcerative colitis (UC) are the most frequent inflammatory bowel disorders (IBD). IBD cause a significant burden to society due to extensive health care utilization from the first clinical symptoms until diagnosis and thereafter due to direct and indirect costs. Besides the socio-economic impact of CD and UC, gastrointestinal and extraintestinal symptoms affect quality of life, but there is remarkably little data about the quality of treatment as assessed by patient satisfaction, quality of life and adherence to guidelines. Thus the aim of this study was to identify variables that influence quality of treatment and quality of life as well as patient satisfaction. Methods: The Essener Zirkel Study was a cross sectional study of 86 IBD-patients with a confirmed diagnosis of CD or UC. They were recruited at primary, secondary and tertiary care settings. Quality of treatment, quality of life and patient satisfaction were evaluated. Consulting behaviour and number of examinations, duration of disease and variables regarding adherence to guidelines were evaluated, too. Results: 59 (69%) patients had CD and 27 had UC (31%). 19% spent more than four years until the suspected diagnosis of IBD was confirmed and visited more than five physicians. All patients showed a significantly reduced quality of life compared to the 1998 German normative population. In spite of being under medical treatment, nearly half of the patients suffered from strong quality of life restricting symptoms. Over all, 35% described their treatment as moderate or bad. Patients who consulted psychotherapists and non-medical practitioners suffered significantly less from depression. Conclusion: Besides structural deficiencies due to the health care policy, we revealed the adherence to guidelines to be a problem area. Our findings support the assumption, that providing better health care and especially maintaining constant patient-physician communication improves patient satisfaction.Claudia Pieper, Sebastian Haag, Stefan Gesenhues, Gerald Holtmann, Guido Gerken and Karl-Heinz Jöcke
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