437 research outputs found

    Isolation und Analyse präemptiver Biomarker beim Kolorektalkarzinom

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    Der generelle Nutzen des Einsatzes von Biomarkern beim CRC ist belegt. Die allgemeine Risikostratifizierung gelingt bereits anhand des Tumorgewebes. Nachteilig an dieser Methode ist allerdings, die Invasivität, um an entsprechendes Gewebe zu gelangen, und die fehlende Möglichkeit der longitudinalen Verlaufsbeobachtung. Das Konzept der „Liquid Biopsy“ ermöglicht, genau diese Schwierigkeit zu umgehen. Im Blut frei zirkulierende Biomarker können isoliert und analysiert werden

    Identification of high-permeability subsurface structures with multiple point geostatistics and normal score ensemble Kalman filter

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    Alluvial aquifers are often characterized by the presence of braided high-permeable paleo-riverbeds, which constitute an interconnected preferential flow network whose localization is of fundamental importance to predict flow and transport dynamics. Classic geostatistical approaches based on two-point correlation (i.e., the variogram) cannot describe such particular shapes. In contrast, multiple point geostatistics can describe almost any kind of shape using the empirical probability distribution derived from a training image. However, even with a correct training image the exact positions of the channels are uncertain. State information like groundwater levels can constrain the channel positions using inverse modeling or data assimilation, but the method should be able to handle non-Gaussianity of the parameter distribution. Here the normal score ensemble Kalman filter (NS-EnKF) was chosen as the inverse conditioning algorithm to tackle this issue. Multiple point geostatistics and NS-EnKF have already been tested in synthetic examples, but in this study they are used for the first time in a real-world casestudy. The test site is an alluvial unconfined aquifer in northeastern Italy with an extension of approximately 3 km2. A satellite training image showing the braid shapes of the nearby river and electrical resistivity tomography (ERT) images were used as conditioning data to provide information on channel shape, size, and position. Measured groundwater levels were assimilated with the NS-EnKF to update the spatially distributed groundwater parameters (hydraulic conductivity and storage coefficients). Results from the study show that the inversion based on multiple point geostatistics does not outperform the one with a multiGaussian model and that the information from the ERT images did not improve site characterization. These results were further evaluated with a synthetic study that mimics the experimental site. The synthetic results showed that only for a much larger number of conditioning piezometric heads, multiple point geostatistics and ERT could improve aquifer characterization. This shows that state of the art stochastic methods need to be supported by abundant and high-quality subsurface data

    Perkutaner Pulmonalklappenersatz und Tissue-Engineering: in vivo Evaluation von selbstexpandierenden, klappentragenden Nitinol-Stents mittels Angiographie im Schafmodell

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    Diese Arbeit handelt vom Verfahren des minimalinvasiven Pulmonalklappenersatzes durch zuvor tissue-engineerte Herzklappen. Ziel soll eine kritische Betrachtung von Lage und Funktion der klappentragenden Stentprothese, unter Nutzung kontrastmittelgestüzter Angiographie, nach einem definierten Versuchszeitraum sein

    The Cost of Routine Follow-Up in Total Joint Arthroplasty and the Influence of These Visits on Treatment Plans

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    Introduction. Many physicians recommend annual or biennial visitsafter total hip and knee arthroplasty (THA and TKA). This studysought to establish the cost of a post-operative visit to both the healthcare system and patient and identify if these visits altered patientmanagement. Methods. A prospective cohort study was conducted using patientspresenting for follow-up after THA or TKA from April throughDecember 2016. All surgeries were performed by a single orthopaedicsurgeon in Wichita, Kansas. All eligible subjects that met the inclusioncriteria received and completed a questionnaire about the personalcost of the visit and their assessment of their function and outcomeafter total joint arthroplasty. The physician also completed a questionnairethat examined the cost of the visit to the health care systemand whether the clinical or radiographic findings altered patient management. Results. Fifty-six patients participated with an average length of follow-up of 4.5 ± 4.1 years since surgery. The average patient cost was135.20±135.20 ± 190.53 (range, 1.651.65 - 995.88), and the average visit timefor the patient was 3.9 ± 2.9 hours. Eighty percent of patients reportedno pain during the clinic encounter, and 11% reported loss of function.Eighty-four percent thought the visit was necessary. Physician timefor each visit lasted 12.9 ± 3.7 minutes (range, 10 - 20 minutes). Only9% of patient encounters resulted in an alteration in patient management.This occurred at an average follow-up time of 3.6 ± 1.8 yearsafter the index procedure. The average cost of each visit to the healthcare system at large was 117.31±60.53(range,117.31 ± 60.53 (range, 93.90 - $428.28). Conclusions. The findings of this study advise total joint patients andorthopaedic surgeons regarding the cost of routine post-operativeappointments and whether these visits alter patient management.The majority of the routine follow-up visits after THA and TKA didnot result in an alteration in patient management, but added substantialcost to the health care system. Kans J Med 2018;11(3):59-66

    High-Risk Corneal Graft Rejection in the Setting of Previous Corneal Herpes Simplex Virus (HSV)-1 Infection

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    Acknowledgments The authors thank M. Robertson and R. Fordyce for technical support during the duration of the study. The work performed in Aberdeen was supported by grant from Action Medical Research UK (SP4328; London, England, UK), NHS Grampian Endowment grant (12/49; Aberdeen, Scotland, UK), and Saving Sight in Grampian (Charity No.SC002938; Aberdeen, Scotland, UK). The work performed in Pittsburgh was supported by a Fight for Sight Post-Doctoral Award (JEK; New York, NY, USA); unrestricted grants from the Western Pennsylvania Medical Eye Bank Foundation (Pittsburgh, PA, USA), Research to Prevent Blindness (New York, NY, USA), and the Eye and Ear Foundation of Pittsburgh (RLH; Pittsburgh, PA, USA); and National Institutes of Health Grants P30EY08098 (RLH; Bethesda, MD, USA) and EY10359 (RLH).Peer reviewedPublisher PD

    Competition among Sellers in Securities Auctions

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    We study simultaneous security-bid second-price auctions with competition among sellers for potential bidders. The sellers compete by designing ordered sets of securities that the bidders can offer as payment for the assets. Upon observing auction designs, potential bidders decide which auctions to enter. We characterize all symmetric equilibria and show that there always exist equilibria in which auctions are in standard securities or their combinations. In large markets the unique equilibrium is auctions in pure cash. We extend the model for competition in reserve prices and show that binding reserve prices never constitute equilibrium as long as equilibrium security designs are not call options. (JEL D44, D82, G10)

    ABET and development in the Northern Cape province: Assessing impacts of CACE courses, 1996-1999

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    This study presents the results of an investigation into the impact of CACE courses for adult educators, trainers and development practitioners. The report describes how the courses affected the training practices and lives of past students. Case studies document and analyse the problems and successes of implementing capacity-building ABET training in the Northern Cape.UK Department for International Development (DFID
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