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Numerous studies showed that postural balance improves through light touch on a stable surface highlighting the importance of haptic information, seemingly downplaying the mechanical contributions of the support. The present study examined the mechanical effects of canes for assisting balance in healthy individuals challenged by standing on a beam. Sixteen participants supported themselves with two canes, one in each hand, and applied minimal, preferred, or maximum force onto the canes. They positioned the canes in the frontal plane or in a tripod configuration. Statistical analysis used a linear mixed model to evaluate the effects on the center of pressure and the center of mass. The canes significantly reduced the variability of the center of pressure and the center of mass to the same level as when standing on the ground. Increasing the exerted force beyond the preferred level yielded no further benefits, although in the preferred force condition, participants exploited the altered mechanics by resting their arms on the canes. The tripod configuration allowed for larger variability of the center of pressure in the task-irrelevant anterior–posterior dimension. High forces had a destabilizing effect on the canes: the displacement of the hand on the cane handle increased with the force. Given this static instability, these results show that using canes can provide not only mechanical benefits but also challenges. From a control perspective, effort can be reduced by resting the arms on the canes and by channeling noise in the task-irrelevant dimensions. However, larger forces exerted onto the canes can also have destabilizing effects and the instability of the canes needs to be counteracted, possibly by arm and shoulder stiffness. Insights into the variety of mechanical effects is important for the design of canes and the instructions of how to use them.  相似文献   
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Thomas Behrens  Calvin Ge  Roel Vermeulen  Benjamin Kendzia  Ann Olsson  Joachim Schüz  Hans Kromhout  Beate Pesch  Susan Peters  Lützen Portengen  Per Gustavsson  Dario Mirabelli  Pascal Guénel  Danièle Luce  Dario Consonni  Neil E. Caporaso  Maria Teresa Landi  John K. Field  Stefan Karrasch  Heinz-Erich Wichmann  Jack Siemiatycki  Marie-Elise Parent  Lorenzo Richiardi  Lorenzo Simonato  Karl-Heinz Jöckel  Wolfgang Ahrens  Hermann Pohlabeln  Guillermo Fernández-Tardón  David Zaridze  John R. McLaughlin  Paul A. Demers  Beata Świątkowska  Jolanta Lissowska  Tamás Pándics  Eleonora Fabianova  Dana Mates  Vladimir Bencko  Lenka Foretova  Vladimír Janout  Paolo Boffetta  Bas Bueno-de-Mesquita  Francesco Forastiere  Kurt Straif  Thomas Brüning 《International journal of cancer. Journal international du cancer》2023,152(4):645-660
There is limited evidence regarding the exposure-effect relationship between lung-cancer risk and hexavalent chromium (Cr(VI)) or nickel. We estimated lung-cancer risks in relation to quantitative indices of occupational exposure to Cr(VI) and nickel and their interaction with smoking habits. We pooled 14 case-control studies from Europe and Canada, including 16 901 lung-cancer cases and 20 965 control subjects. A measurement-based job-exposure-matrix estimated job-year-region specific exposure levels to Cr(VI) and nickel, which were linked to the subjects' occupational histories. Odds ratios (OR) and associated 95% confidence intervals (CI) were calculated by unconditional logistic regression, adjusting for study, age group, smoking habits and exposure to other occupational lung carcinogens. Due to their high correlation, we refrained from mutually adjusting for Cr(VI) and nickel independently. In men, ORs for the highest quartile of cumulative exposure to CR(VI) were 1.32 (95% CI 1.19-1.47) and 1.29 (95% CI 1.15-1.45) in relation to nickel. Analogous results among women were: 1.04 (95% CI 0.48-2.24) and 1.29 (95% CI 0.60-2.86), respectively. In men, excess lung-cancer risks due to occupational Cr(VI) and nickel exposure were also observed in each stratum of never, former and current smokers. Joint effects of Cr(VI) and nickel with smoking were in general greater than additive, but not different from multiplicative. In summary, relatively low cumulative levels of occupational exposure to Cr(VI) and nickel were associated with increased ORs for lung cancer, particularly in men. However, we cannot rule out a combined classical measurement and Berkson-type of error structure, which may cause differential bias of risk estimates.  相似文献   
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Journal of Pharmacokinetics and Pharmacodynamics - Clinical trials in patients with ulcerative colitis (UC) face the challenge of high and variable placebo response rates. The Mayo Clinical Score...  相似文献   
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Hunck  S.  Engelhard  K.  Mildenberger  P.  Kurz  S. 《Der Anaesthesist》2022,71(9):689-696
Die Anaesthesiologie - Die COVID-19-Pandemie hat die medizinische Lehre weltweit verändert. Seit dem Sommersemester 2020 stehen digitale Lehrformate im Fokus, deren Einsatz zuvor in...  相似文献   
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Proceedings of the National Academy of Sciences, India Section B: Biological Sciences - Adoption of intercropping offers an opportunity to get additional income and to protect the crops from insect...  相似文献   
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Clinical Oral Investigations - Mechanisms of wound healing are often impaired in patients with osteonecrosis of the jaw (ONJ). According to the guidelines for the treatment of this disease, early...  相似文献   
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Journal of Interventional Cardiac Electrophysiology - Delineate retrospectively and prospectively the incidence and characteristics of transient ST-segment elevation during transseptal puncture....  相似文献   
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