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TZID:Europe/Paris
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UID:1-160@lptms.universite-paris-saclay.fr
DTSTART:20130726T140000Z
DTEND:20130726T150000Z
DTSTAMP:20130723T101912Z
URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i
 nterface-seminar-matthieu-caruel/
SUMMARY:Physics-Biology interface seminar: Matthieu Caruel - Moyen Amphi\, 
 Building 510\, Université Paris-Saclay Orsay - 26 Juil 13 14:00
DESCRIPTION:Muscle power-stroke as a collective mechanical phenomenon\nMatt
 hieu Caruel (Inria and École Polytechnique)\nThe mechanism of muscle cont
 raction\, residing in nano-scale interaction between actin and myosin fila
 ments\, was intensely studied by using fast loading protocols. These exper
 iments revealed the important mechanical role of the internal conformation
 al change inside protruding myosin heads known as the power-stroke. It was
  realized that fast force recovery after abrupt loading\, taking place at 
 1 ms time scale\, is a purely mechanical phenomenon linked exclusively to 
 the power-stroke and not limited by metabolic fuel delivery.\nIn this pres
 entation\, we explore previously unnoticed difference in fast force recove
 ry taking place in hard and soft loading devices and propose a purely mech
 anical model that explains the origin of this unusual behavior. We link th
 e inequivalence of soft and hard loading ensembles to the presence of long
  range interactions between the individual actin-myosin cross-links known 
 as cross-bridges. Our fit of experimental data suggests that 'muscle mater
 ial' is finely tuned to perform close to a critical point which explains l
 arge fluctuations observed at stall forces. The proposed mean field model 
 clarifies the collective nature of the power-stroke and reveal new propert
 ies of the celebrated Huxley and Simmons 1971 model.
LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R
 ue Georges Clemenceau\, orsay\, France
GEO:48.698187;2.181768
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  orsay\, France;X-APPLE-RADIUS=100;X-TITLE=Moyen Amphi\, Building 510\, Un
 iversité Paris-Saclay Orsay:geo:48.698187,2.181768
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