707 research outputs found

    Doping by adolescent soccer players

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    Introduction: There is evidence that between 3% to 5% of young athletes use performance enhancing drugs that are identified as doping and thereby banned under the World Anti-Doping Code. The incidence of doping varies by factors such as type of sport, age of respondents, type of drugs, and method of data collection. Soccer is one of a handful of sports not to be associated with doping. The longstanding position of authorities has been that there is no systematic doping in soccer as it is believed that doping in skill based sports offers few advantages to players. Methods: The present study examined doping attitudes, beliefs (including perceived effect on health) and behaviours in 78 soccer players (aged 12 to 17 years). The method of data collection was a self-completion survey. Results: It was found that 5% of the players were doping, many for image rather than performance enhancement. A quarter of players personally knew a player in their competitive grade who was using banned performance enhancing drugs. The participants estimated that about 16% of soccer players are doping. Conclusions: The study shows that some young soccer players are doping and others express attitudes and beliefs that suggest they too may dope in the future. Young soccer players do not differ from other adolescent athletes. Soccer faces the same doping threats as other modern sports and should ensure that its coaches and administrators do not falsely believe that their players are immune to allure of doping

    CO17 107. Experiencia inicial con la prótesis de válvula aórtica sin sutura 3f-enable de segunda generación

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    ObjetivosLa válvula aórtica ATS-3F-Enable™ representa una nueva generación con pericardio equino, stent de nitinol autoexpandible e implantación sin suturas. Evaluamos la técnica de implantación, la seguridad y efectividad de la válvula así como los resultados al año de implantación.Material y métodosAnálisis de resultados en una serie de 27 pacientes consecutivos con estenosis de válvula aórtica y reemplazamiento aislado de la válvula por una ATS-3F-Enable™ entre agosto de 2007 y febrero de 2009. La edad media fue 75,7±6,6 años. Diecisiete mujeres (63%). EuroSCORE mediano: 8, y medio: 7,1±1,7.ResultadosEl tamaño medio de válvula implantada fue de 23mm (franja: 19-27mm). La media de tiempo de clampaje aórtico fue de 39,8±15min (franja: 29-103min). La media de tiempo de circulación extracorpórea fue de 58,6±20min (franja: 41-127). La media de tiempo de hospitalización fue de 11 días (7-22). No hubo mortalidad durante la intervención. Al alta, los gradientes de presión transvalvular medio y alto con ecocardiografía fueron de 11,6 y 18,5mmHg, respectivamente. Dos pacientes presentaron una fuga paravalvular moderada y un paciente fue reoperado a causa de una fuga paravalvular grave. Se requirió la implantación de marcapasos en cinco pacientes (18,5%). El seguimiento al cabo de 1 año fue del 100% y la supervivencia fue del 86%.ConclusionesLa prótesis aórtica ATS-3F-Enable™ puede ser implantada con seguridad y presenta resultados hemodinámicos favorables. El stent autoexpandible y la técnica sin sutura permite una implantación rápida, sin embargo, no tan rápida como esperado. Acumulación de experiencia y algunas modificaciones en el diseño de la prótesis podrán ayudar a perfeccionar la técnica

    Cesium and Strontium Contamination of Nuclear Plant Stainless Steel : Implications for Decommissioning and Waste Minimization

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    Stainless steels can become contaminated with radionuclides at nuclear sites. Their disposal as radioactive waste would be costly. If the nature of steel contamination could be understood, effective decontamination strategies could be designed and implemented during nuclear site decommissioning in an effort to release the steels from regulatory control. Here, batch uptake experiments have been used to understand Sr and Cs (fission product radionuclides) uptake onto AISI Type 304 stainless steel under conditions representative of spent nuclear fuel storage (alkaline ponds) and PUREX nuclear fuel reprocessing (HNO3). Solution (ICP-MS) and surface measurements (GD-OES depth profiling, TOF-SIMS, and XPS) and kinetic modeling of Sr and Cs removal from solution were used to characterize their uptake onto the steel and define the chemical composition and structure of the passive layer formed on the steel surfaces. Under passivating conditions (when the steel was exposed to solutions representative of alkaline ponds and 3 and 6 M HNO3), Sr and Cs were maintained at the steel surface by sorption/selective incorporation into the Cr-rich passive film. In 12 M HNO3, corrosion and severe intergranular attack led to Sr diffusion into the passive layer and steel bulk. In HNO3, Sr and Cs accumulation was also commensurate with corrosion product (Fe and Cr) readsorption, and in the 12 M HNO3 system, XPS documented the presence of Sr and Cs chromates.Peer reviewe

    Comparing quality of dying and death perceived by family members and nurses for patients dying in US and Dutch ICUs

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    BACKGROUND: The Quality of Dying and Death (QODD) questionnaire is used as a selfreported measure to allow families and clinicians to assess patients' quality of dying and death. We evaluated end-of-life (EOL) experiences as measured by the QODD completed by families and nurses in the United States and the Netherlands to explore similarities and differences in these experiences and identify opportunities for improving EOL care. METHODS: Questionnaire data were gathered from family members of patients dying in the ICU and nurses caring for these patients. In The Netherlands, data were gathered in three teaching hospitals, and data was gathered from 12 sites participating in a randomized trial in the United States. The QODD consists of 25 items and has been validated in the United States. RESULTS: Data from 446 patients were analyzed (346 in the United States and 100 in the Netherlands). Dutch patients were older than those in the United States (72 + 10.2 years vs 65 + 16.0 years; P <.0025). The family-assessed overall QODD score was the same in both countries: the Netherlands = median, 9; interquartile range (IQR), 8-10 and the United States = median, 8; IQR, 5-10. US family members rated the quality of two items higher than did the Netherlands families: "time spent with loved ones" and "time spent alone." Nurseassessed QODD ratings varied: the single-item QODD summary score was significantly higher in the Netherlands (the Netherlands: median, 9; IQR, 8-10 vs the United States: median, 7; IQR, 5-8; P <.0025), whereas the QODD total score was higher in the United States (the Netherlands: median, 6.9; IQR, 5.5-7.6 vs the United States: median, 7.1; IQR, 5.88.4; P = .014), although it did not meet our criteria for statistical significance. Of the 22 nurse-assessed items, 10 were significantly different between the Netherlands and the United States, with eight having higher scores in the United States and 2 having higher scores in the Netherlands. CONCLUSIONS: The QODD was rated similarly by family members in the United States and the Netherlands but varied when assessed by nurses. These differences may be due to organizational or cultural differences between the two countries or to expectations of respondents

    The Effects of Twitter Sentiment on Stock Price Returns

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    Social media are increasingly reflecting and influencing behavior of other complex systems. In this paper we investigate the relations between a well-know micro-blogging platform Twitter and financial markets. In particular, we consider, in a period of 15 months, the Twitter volume and sentiment about the 30 stock companies that form the Dow Jones Industrial Average (DJIA) index. We find a relatively low Pearson correlation and Granger causality between the corresponding time series over the entire time period. However, we find a significant dependence between the Twitter sentiment and abnormal returns during the peaks of Twitter volume. This is valid not only for the expected Twitter volume peaks (e.g., quarterly announcements), but also for peaks corresponding to less obvious events. We formalize the procedure by adapting the well-known "event study" from economics and finance to the analysis of Twitter data. The procedure allows to automatically identify events as Twitter volume peaks, to compute the prevailing sentiment (positive or negative) expressed in tweets at these peaks, and finally to apply the "event study" methodology to relate them to stock returns. We show that sentiment polarity of Twitter peaks implies the direction of cumulative abnormal returns. The amount of cumulative abnormal returns is relatively low (about 1-2%), but the dependence is statistically significant for several days after the events

    Emergent Properties of Tumor Microenvironment in a Real-life Model of Multicell Tumor Spheroids

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    Multicellular tumor spheroids are an important {\it in vitro} model of the pre-vascular phase of solid tumors, for sizes well below the diagnostic limit: therefore a biophysical model of spheroids has the ability to shed light on the internal workings and organization of tumors at a critical phase of their development. To this end, we have developed a computer program that integrates the behavior of individual cells and their interactions with other cells and the surrounding environment. It is based on a quantitative description of metabolism, growth, proliferation and death of single tumor cells, and on equations that model biochemical and mechanical cell-cell and cell-environment interactions. The program reproduces existing experimental data on spheroids, and yields unique views of their microenvironment. Simulations show complex internal flows and motions of nutrients, metabolites and cells, that are otherwise unobservable with current experimental techniques, and give novel clues on tumor development and strong hints for future therapies.Comment: 20 pages, 10 figures. Accepted for publication in PLOS One. The published version contains links to a supplementary text and three video file

    Isotopic Composition of Light Nuclei in Cosmic Rays: Results from AMS-01

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    The variety of isotopes in cosmic rays allows us to study different aspects of the processes that cosmic rays undergo between the time they are produced and the time of their arrival in the heliosphere. In this paper we present measurements of the isotopic ratios 2H/4He, 3He/4He, 6Li/7Li, 7Be/(9Be+10Be) and 10B/11B in the range 0.2-1.4 GeV of kinetic energy per nucleon. The measurements are based on the data collected by the Alpha Magnetic Spectrometer, AMS-01, during the STS-91 flight in 1998 June.Comment: To appear in ApJ. 12 pages, 11 figures, 6 table

    Removal of Hepatitis C Virus-Infected Cells by a Zymogenized Bacterial Toxin

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    Hepatitis C virus (HCV) infection is a major cause of chronic liver disease and has become a global health threat. No HCV vaccine is currently available and treatment with antiviral therapy is associated with adverse side effects. Moreover, there is no preventive therapy for recurrent hepatitis C post liver transplantation. The NS3 serine protease is necessary for HCV replication and represents a prime target for developing anti HCV therapies. Recently we described a therapeutic approach for eradication of HCV infected cells that is based on protein delivery of two NS3 protease-activatable recombinant toxins we named “zymoxins”. These toxins were inactivated by fusion to rationally designed inhibitory peptides via NS3-cleavable linkers. Once delivered to cells where NS3 protease is present, the inhibitory peptide is removed resulting in re-activation of cytotoxic activity. The zymoxins we described suffered from two limitations: they required high levels of protease for activation and had basal activities in the un-activated form that resulted in a narrow potential therapeutic window. Here, we present a solution that overcame the major limitations of the “first generation zymoxins” by converting MazF ribonuclease, the toxic component of the E. coli chromosomal MazEF toxin-antitoxin system, into an NS3-activated zymoxin that is introduced to cells by means of gene delivery. We constructed an expression cassette that encodes for a single polypeptide that incorporates both the toxin and a fragment of its potent natural antidote, MazE, linked via an NS3-cleavable linker. While covalently paired to its inhibitor, the ribonuclease is well tolerated when expressed in naïve, healthy cells. In contrast, activating proteolysis that is induced by even low levels of NS3, results in an eradication of NS3 expressing model cells and HCV infected cells. Zymoxins may thus become a valuable tool in eradicating cells infected by intracellular pathogens that express intracellular proteases
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