2,718 research outputs found

    Strategies for estimating human exposure to mycotoxins via food

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    In this review, five strategies to estimate mycotoxin exposure of a (sub-) population via food, including data collection, are discussed with the aim to identify the added values and limitations of each strategy for risk assessment of these chemicals. The well-established point estimate, observed individual mean, probabilistic and duplicate diet strategies are addressed, as well as the emerging human biomonitoring strategy. All five exposure assessment strategies allow the estimation of chronic (long-term) exposure to mycotoxins, and, with the exception of the observed individual mean strategy, also acute (short-term) exposure. Methods for data collection, i.e. food consumption surveys, food monitoring studies and total diet studies are discussed. In food monitoring studies, the driving force is often enforcement of legal limits, and, consequently, data are often generated with relatively high limits of quantification and targeted at products suspected to contain mycotoxin levels above these legal limits. Total diet studies provide a solid base for chronic exposure assessments since they provide mycotoxin levels in food based on well-defined samples and including the effect of food preparation. Duplicate diet studies and human biomonitoring studies reveal the actual exposure but often involve a restricted group of human volunteers and a limited time period. Human biomonitoring studies may also include exposure to mycotoxins from other sources than food, and exposure to modified mycotoxins that may not be detected with current analytical methods. Low limits of quantification are required for analytical methods applied for data collection to avoid large uncertainties in the exposure due to high numbers of left censored data, i.e. with levels below the limit of quantification

    Organizational Best Practices for Transportation Projects Delivered Using Alternative Contracting Methods

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    The use of Alternative Contracting Methods (ACM) to deliver US transportation projects has reached a point where a definitive set of best practices can be identified to leverage the lessons learned by early ACM adopters. The most pressing need is for guidance on how public agencies organize to implement ACMs in a budget-constrained environment where the possibility of increasing the number of public agency engineers is nil. This paper is based on mining the survey response data from 6 National Cooperative Highway Research Program (NCHRP) synthesis reports on ACM topics and proposes a framework for analyzing ACM practices deemed effective by peer-reviewed research to determine if each practice can be classified as a best practice. Importance index theory provides the analytical foundation for the framework and provides a ranking of candidate best practices in order of each practice’s importance and effectiveness. Nine effective ACM practices were identified and evaluated with only one, “appointing an agency ACM champion,” meeting the objective criteria for a best practice. The paper’s major contribution is to provide the suite of 1 best and 8 effective practices that can be employed when developing the organization for an agency that has decided to implement ACM project delivery.Keywords: Alternative contracting methods, best practices, organizational structure, index number theory

    Culture-negative bivalvular endocarditis with myocardial destruction in a patient with systemic lupus erythematosus: a case report

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    Culture-negative endocarditis has long been associated with systemic lupus erythematosus, but is usually asymptomatic or involves a single valve. We present a patient with destructive culture-negative endocarditis that remains without a microbial etiology despite an exhaustive workup using advanced diagnostic techniques in a patient with systemic lupus erythematosus

    Diagnostic procedures for non-small-cell lung cancer (NSCLC): recommendations of the European Expert Group

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    Background There is currently no Europe-wide consensus on the appropriate preanalytical measures and workflow to optimise procedures for tissue-based molecular testing of non-small-cell lung cancer (NSCLC). To address this, a group of lung cancer experts (see list of authors) convened to discuss and propose standard operating procedures (SOPs) for NSCLC. Methods Based on earlier meetings and scientific expertise on lung cancer, a multidisciplinary group meeting was aligned. The aim was to include all relevant aspects concerning NSCLC diagnosis. After careful consideration, the following topics were selected and each was reviewed by the experts: surgical resection and sampling; biopsy procedures for analysis; preanalytical and other variables affecting quality of tissue; tissue conservation; testing procedures for epidermal growth factor receptor, anaplastic lymphoma kinase and ROS proto-oncogene 1, receptor tyrosine kinase (ROS1) in lung tissue and cytological specimens; as well as standardised reporting and quality control (QC). Finally, an optimal workflow was described. Results Suggested optimal procedures and workflows are discussed in detail. The broad consensus was that the complex workflow presented can only be executed effectively by an interdisciplinary approach using a well-trained team. Conclusions To optimise diagnosis and treatment of patients with NSCLC, it is essential to establish SOPs that are adaptable to the local situation. In addition, a continuous QC system and a local multidisciplinary tumour-type-oriented board are essential

    Socio-Economic Burden of Myocardial Infarction Among Cancer Patients

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    Cancer patients face a higher risk of future myocardial infarction (MI), even after completion of anticancer therapies. MI is a critical source of physical and financial stress in non-cancer patients, but its impacts associated with cancer patients also saddled with the worry (stress) of potential reoccurrence is unknown. Therefore, we aimed to quantify MI's stress and financial burden after surviving cancer and compare to those never diagnosed with cancer. Utilizing cross-sectional national survey data from 2013-2018 derived from publicly available U.S. datasets, the National Health Interview Survey (NHIS), and economic data from the National Inpatient Sample (NIS), we compared the socio-economic outcomes among those with MI by cancer-status. We adjusted for social, demographic, and clinical factors. Overall, 19,504 (10.2%) of the 189,836 NHIS survey responders reported having cancer for more than 1 year. There was an increased prevalence of MI among cancer survivors compared to non-cancer patients (8.8% vs. 3.2%, P0.05). There was no difference in annual residual family income by cancer status; however, 3 lowest deciles of residual income representing 21.1% cancer-survivor with MI had a residual income of <$9,000. Myocardial infarction continues to represent an immense source of financial and perceived stress. In conclusion, although cancer patients face a higher risk of subsequent MI, this does not appear to advance their reported stress significantly

    Electric Field-Tuned Topological Phase Transition in Ultra-Thin Na3Bi - Towards a Topological Transistor

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    The electric field induced quantum phase transition from topological to conventional insulator has been proposed as the basis of a topological field effect transistor [1-4]. In this scheme an electric field can switch 'on' the ballistic flow of charge and spin along dissipationless edges of the two-dimensional (2D) quantum spin Hall insulator [5-9], and when 'off' is a conventional insulator with no conductive channels. Such as topological transistor is promising for low-energy logic circuits [4], which would necessitate electric field-switched materials with conventional and topological bandgaps much greater than room temperature, significantly greater than proposed to date [6-8]. Topological Dirac semimetals(TDS) are promising systems in which to look for topological field-effect switching, as they lie at the boundary between conventional and topological phases [3,10-16]. Here we use scanning probe microscopy/spectroscopy (STM/STS) and angle-resolved photoelectron spectroscopy (ARPES) to show that mono- and bilayer films of TDS Na3Bi [3,17] are 2D topological insulators with bulk bandgaps >400 meV in the absence of electric field. Upon application of electric field by doping with potassium or by close approach of the STM tip, the bandgap can be completely closed then re-opened with conventional gap greater than 100 meV. The large bandgaps in both the conventional and quantum spin Hall phases, much greater than the thermal energy kT = 25 meV at room temperature, suggest that ultrathin Na3Bi is suitable for room temperature topological transistor operation
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