Assay validity of point-of-care platelet function tests in thrombocytopenic blood samples

IntroductionPoint-of-care (POC) platelet function tests are faster and easier to perform than in-depth assessment by flow cytometry. At low platelet counts, however, POC tests are prone to assess platelet function incorrectly. Lower limits of platelet count required to obtain valid test results were defined and a testing method to facilitate comparability between different tests was established.Materials and methodsWe assessed platelet function in whole blood samples of healthy volunteers at decreasing platelet counts (> 100, 80-100, 50-80, 30-50 and < 30 x10⁹/L) using two POC tests: impedance aggregometry and in-vitro bleeding time. Flow cytometry served as the gold standard. The number of platelets needed to reach 50% of the maximum function (ED₅₀) and the lower reference limit (ED_ref) were calculated to define limits of test validity.ResultsThe minimal platelet count required for reliable test results was 100 x10⁹/L for impedance aggregometry and in-vitro bleeding time but only 30 x10⁹/L for flow cytometry. Comparison of ED₅₀ and ED_ref showed significantly lower values for flow cytometry than either POC test (P value < 0.05) but no difference between POC tests nor between the used platelet agonists within a test method.ConclusionCalculating the ED₅₀ and ED_ref provides an effective way to compare values from different platelet function assays. Flow cytometry enables correct platelet function testing as long as platelet count is > 30 x10⁹/L whereas impedance aggregometry and in-vitro bleeding time are inconsistent unless platelet count is > 100 x10⁹/L.     

Sleep of professional athletes: Underexploited potential to improve health and performance

Sleep disorders have become increasingly prevalent affecting health and working ability. Restorative sleep may be considered important for athletes’ successful recovery and performance. However, some athletes seem to experience major problems in sleeping. Thus far, there is limited scientific information about their sleep. This study aimed to evaluate the quality of sleep and the prevalence of sleep disorders as well as the impact of a structured sleep counselling protocol in professional athletes. A total of 107 professional ice hockey players participated in the study. The exploratory observational 1-year follow-up study consisted of questionnaire-based sleep assessment followed by general sleep counselling and, when needed, polysomnography and an individual treatment plan. One in every four players was found to have a significant problem in sleeping. All athletes considered sleep essential for their health and three in every four players considered that counselling would improve their performance. Counselling and individual treatment were found to improve significantly the quality of sleep with the mean alteration of 0.6 (95% CI 0.2–1.0, P = 0.004) in a scale from 0 to 10. Our results support that sleep problems are common in professional athletes. However, systematic examination, counselling and individual treatment planning can improve the quality of their sleep.     

During early to mid adolescence,moderate to vigorous physical activity is associated with restoring sleep,psychological functioning,mental toughness and male gender

Numerous studies showed that regular physical activity (PA) is associated with both favourable and restorative sleep and improved psychological functioning (PF). However, there is little research on the topic covering the early to mid-adolescence period. Moreover, curiosity and exploratory behaviour (CEB) and mental toughness (MT) as a result of PA remains thus far uninvestigated, as do possible gender differences. The aim of the present study was to explore the associations between PA, subjective sleep (sS), PF, CEB, and MT during early to mid-adolescence. A total of 1361 participants (mean age = 13.37 years; range: 11–16 years; 51.2% female) took part in the study. They completed questionnaires covering PA, sS, PF, CEB, and MT. Greater PA was related to improved PF, better sS, and increased CEB and MT. Compared to male participants, females reported less PA, poorer sS, and had lower PF and MT scores. The present pattern of results suggests that during early and mid-adolescence greater PA was associated with more favourable sS and better PF, including CEB and MT, and that female participants reported lower scores in PA, sS, and PF. Accordingly, if PA has a favourable impact on sleep and psychological functioning, then data suggest that sports participation should be more tailored to increase motivation among female adolescents.     

Zwischenbetriebliche elektronische Katalogsysteme: Netzwerkstrategische Gestaltungsoptionen und Erfolgsfaktoren

Zusammenfassung. Das Internet und darauf aufbauende Technologien er?ffnen neue Potentiale für zwischenbetriebliche Informationssysteme und f?rdern die elektronische Unterstützung von Gesch?ftsbeziehungen. Dabei bleibt jedoch das grunds?tzliche Problem bestehen, da? der Hauptinvestor jeweils eine gewisse Anzahl an Teilnehmern ben?tigt, um eine angemessene Verzinsung der für die Systementwicklung und -implementierung eingesetzten Ressourcen zu erreichen. Da es sich im zwischenbetrieblichen Kontext bei den Transaktionspartnern in der Regel um entscheidungsautonome Organisationseinheiten handelt, kann davon ausgegangen werden, da? die kritische Masse nur dann erreicht wird, wenn sich für die Teilnehmer selbst wiederum eine angemessene Verzinsung der für Anbindung und Systemanpassung notwendigen individuellen Aufwendungen ergibt. Dem Hauptinvestor stehen dabei eine Reihe von Gestaltungsoptionen zur Verfügung, denen jeweils unterschiedliche Erfolgsfaktoren zuzuordnen sind. In der Vergangenheit dominierten einerseits auf Zwang ausgerichtete, stark kompetitive Vorgehensweisen und andererseits kooperative Strategien, wie etwa die freiwillige Beschr?nkung der Anzahl an Zulieferbeziehungen im Rahmen vertrauensbildender Ma?nahmen. Mit dem Aufkommen offener Kommunikationsstandards und neuer Technologien lassen sich diese von relativ geringen zus?tzlichen finanziellen Belastungen gekennzeichneten Strategien m?glicherweise nicht mehr aufrechterhalten, und es wird notwendig, neue Optionen in Betracht zu ziehen, wie etwa die Subventionierung einzelner Systemteilnehmer oder die Verbesserung des Gesamtsystems, die jeweils sowohl kompetitive als auch kooperative Elemente aufweisen. Der vorliegende Beitrag diskutiert diese These am Beispiel zwischenbetrieblicher elektronischer Katalogsysteme, wie sie in jüngster Zeit im Kontext elektronischer Absatz- und Beschaffungssysteme sowie elektronischer M?rkte an Bedeutung gewinnen. Eingegangen am 16. Dezember 1999 / Angenommen am 15. April 2000     

Postural control and physiological responses to a simulated match in U-20 judo competitors

Abstract

The aim was to evaluate the effects of judo combat on the athletes’ postural control (PC) and physiological loading before, during and after a simulated match. Seventeen under-20 regional and national level athletes completed one modified 7-min match. At baseline, during the combat (3rd and 7th minutes) and 2-min post-match centre of pressure (CoP) parameters were assessed. Heart rate (HR), blood lactate (BLa) and rating of perceived exertion (RPE) and local RPE (LRPE) were collected. Significant increments were observed in CoP mean positioning and velocity at 3rd and 7th minutes, but the CoP deviation in both axes was unaffected. HR and BLa were elevated at 3rd and 7th minutes, and they remained elevated 2-min post-match. However, CoP returned to baseline 2-min post-match. RPE was elevated at 3rd and 7th minutes and the greatest effort was displayed in the Deltoid and Quadriceps. Thus, one simulated judo match stimulates a significant metabolic response and balance is degraded, with the greatest effects on the anterior–posterior axis and it recovers to baseline level after 2 min of passive rest. The physiological load cannot be regarded as a potential predictor variable of CoP. Overall, a judo match predominantly affects the upper body than the other body parts.     

Promoting Curiosity?

Science & Education - Curiosity is a wonder of the human mind. It goes to the heart of modernity, as a driving force for learning, novel insights, and innovation, both for individuals and...     

Sports activity patterns and cardio-metabolic health over time among adults in Germany: Results of a nationwide 12-year follow-up study

BackgroundPhysical activity is favorable for health, and vigorous sports activity is particularly beneficial. This study investigates the association between changes in sports participation patterns over time and cardio-metabolic and self-perceived health outcomes.MethodsData from 3752 adults (18–79 years of age) who participated in 2 national health interview and examination surveys in 1997–1999 and 2008–2011 were included, with a mean follow-up time of about 12 years. A change in self-reported sports activity was analyzed with respect to the incidence of type 2 diabetes, coronary heart disease (CHD), hypertension, obesity, dyslipidemia, metabolic syndrome, and poor self-perceived health. Participants with pre-existing disease or risk factor of interest at baseline were excluded from the analysis. Being sufficiently active in sports was specified as doing sports for at least 1–2 h per week, and 4 activity categories were defined: 1) inactive at both time points (inactive–inactive), 2) inactive at baseline and active at follow-up (inactive–active), 3) active at baseline and inactive at follow-up (active–inactive), and 4) active at both time points (active–active). Associations between sports activity engagement and health outcomes were estimated by logistic regression models with different stages of adjustments.ResultsNot engaging in any regular sports activity at both time points (inactive–inactive) was associated with higher rates of type 2 diabetes (odds ratio (OR) = 1.82, 95% confidence interval (95%CI): 1.08–3.08), CHD (OR = 1.82, 95%CI: 1.16–2.84), hypertension (OR = 1.36, 95%CI: 1.03–1.81), metabolic syndrome (OR = 1.58, 95%CI: 1.08–2.32), and poor self-perceived health (OR = 2.54, 95%CI: 1.83–3.53) compared to doing regular sports for a minimum of 1–2 h per week over time (active–active). In case of change from inactivity to any regular sports activity (inactive–active), the rate of risk factor occurrence was not statistically different from the active–active reference group except for poor self-perceived health, but it was higher for type 2 diabetes (OR = 2.15, 95%CI: 1.12–4.14) and CHD (OR = 1.77, 95%CI: 1.03–3.03). Being active at baseline but inactive at follow-up (active–inactive) was not associated with higher disease incidence of type 2 diabetes (OR = 0.70, 95%CI: 0.25–1.97) or CHD (OR = 1.20, 95%CI: 0.49–2.99), but was associated with higher rates of hypertension (OR = 1.61, 95%CI: 1.11–2.34), obesity (OR = 2.34, 95%CI: 1.53–3.57), metabolic syndrome (OR = 1.70, 95%CI: 1.11–2.63), and poor self-perceived health (OR = 2.16, 95%CI: 1.53–3.07) at follow-up.ConclusionEven a low weekly quantity (1–2 h) of regular sports activity is partly associated with health benefits. Being formerly but not currently active was not associated with an increased disease incidence, but was associated with a higher risk-factor development compared to the reference group (active–active). Becoming active was preventive for risk-factor development but was not preventive for disease incidence, which probably means that the health benefits from sports activity are not sustainable and disease incidence is only shifted to a later period in life. For this reason, the promotion of and commitment to regular sports activity should be addressed as early as possible over the lifespan to achieve the best health benefits.     

Core executive functions are selectively related to different facets of motor competence in preadolescent children

Background: Although accumulating evidence suggests that motor and cognitive development is interrelated, only a few studies have investigated links between executive function and motor control. Therefore, the present cross-sectional study examined the relationship between motor competences and core components of executive functioning, including inhibitory control, working memory and cognitive flexibility. Methods: In 89 preadolescent children, motor competences were assessed using the MOBAK-5 test battery. Additionally, all participants completed computer-based versions of the Flanker task, which included standard and switch blocks, and the 2-Back task. Results: Partial correlations (correcting for age, gender and body mass index) revealed that locomotor skills were associated with the adjusted hit-rate on the 2-Back task (r?=?0.34) whereas object control was linked with conflict score on the Flanker task (r?=??0.39). In contrast, there was no correlation between switch costs and motor competences. Conclusion: In preadolescent children, high competences in locomotor skills and object control skills are associated with high performance on specific executive function tasks. This finding supports the current view that motor competences and cognitive control share some common underlying processes.     

Parameter study using a finite element simulation of a carving Alpine ski to investigate the turn radius and its dependence on edging angle,load, and snow properties

For ski manufacturers, it is important to know how a given ski-binding system performs under different loading conditions. Important performance parameters are the ski deformation and the resulting turn radius. This study focuses on carving turns. The aims of this study were: (1) to investigate the dependence of the turn radius on edging angle, load on the binding, and snow hardness using a finite element (FE) simulation, and (2) to compare the results with predictions of a frequently used model introduced by Howe. The FE simulation used a quasi-static approach (similar to Howe’s model), but the ski–snow interaction model incorporated the groove that forms in the snow during a carved turn. Up to edging angles of 40°, the results of the FE simulation agreed well with Howe’s model. However, for large edging angles (>50°) the calculated turn radius leveled out, whereas Howe’s model tends to zero. This effect was more pronounced for soft snow than for hard snow conditions. Increasing forces on the binding caused a decrease in the calculated turn radii. In summary, the FE simulation showed that particularly at large edging angles the groove in the snow needs to be considered in models of the ski–snow interaction or in computations of the turn radius.     

Mentale Toughness im Sport

The present article reviews the previous literature on mental toughness in sport. The review demonstrates that qualitative researchers have been able to establish conceptual clarity and provide guidance for operationalizing the concept. As a consequence, several quantitative questionnaires have been developed beyond the Psychological Performance Inventory (PPI). Meanwhile, there is preliminary evidence for the validity and reliability of these instruments. Moreover, researchers showed that mental toughness is associated with higher achievement levels or performance outcomes in elite athletes. Regarding the underlying mechanisms, prior research indicated that mentally tough athletes use more positive coping strategies. Although researchers agree that mental toughness is a rather stable construct, experimental research showed that mental skill training influenced mental toughness in a positive fashion. To date, there is a great need for more quantitative, longitudinal and experimental research. Also, a biopsychological approach offers an interesting avenue for future studies.