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The ''Q''10 temperature coefficient is a measure of the rate of change of a biological or chemical system as a consequence of increasing the temperature by 10 °C. There are many examples where the ''Q''10 is used, one being the calculation of the nerve conduction velocity and another being calculating the contraction velocity of muscle fibres. It can also be applied to chemical reactions and many other systems. The ''Q''10 is calculated as: : where : ''R'' is the rate : ''T'' is the temperature in Celsius degrees or kelvins. ''Q''10 is a unitless quantity, as it is the factor by which a rate changes, and is a useful way to express the temperature dependence of a process. For most biological systems, the ''Q''10 value is ~ 2 to 3.〔''Reyes, A.B., Pendergast, J.S., and Yamazaki, S. 2008. Mammalian peripheral circadian oscillators are temperature compensated. J. Biol. Rhythms 23: 95-98.''〕 ==Q10 Coefficient and Muscle Performance== The temperature of a muscle has a significant effect on the velocity and power of the muscle contraction, with performance generally declining with decreasing temperatures and increasing with rising temperatures. The Q10 coefficient represents the degree of temperature dependence a muscle exhibits as measured by contraction rates. A Q10 of 1.0 indicates thermal independence of a muscle whereas an increasing Q10 value indicates increasing thermal dependence. Values less than 1.0 indicate a negative or inverse thermal dependence, i.e., a decrease in muscle performance as temperature increases.〔Bennett, A.F., 1984. Thermal dependence of muscle function. ''Am. J. Physiol. 247'', R217-R229.〕 Q10 values for biological processes vary with temperature. Decreasing muscle temperature results in a substantial decline of muscle performance such that a 10 degree Celsius temperature decrease results in at least a 50% decline in muscle performance.〔Deban, S.M. and Lappin, A.K. 2011. Thermal effects on the dynamics and motor control of ballistic prey capture in toads: maintaining high performance at low temperature. ''J. Exp. Biol''.214, 1333-1346.〕 At some minimum temperature biological systems do not function at all, but performance increases rapidly with rising temperature (Q10 of 2-4) to a maximum performance level and thermal independence (Q10 of 1.0-1.5). With continued increase in temperature, performance decreases rapidly (Q10 of 0.2-0.8) up to a maximum temperature at which all biological function again ceases.〔Bennett, A.F., 1990. Thermal dependence of locomotor capacity. ''Am. J. Physiol.'' 259,R253-R258〕 Within vertebrates, different skeletal muscle activity has correspondingly different thermal dependencies. The rate of muscle twitch contractions and relaxations are thermally dependent (Q10 of 2.0-2.5), whereas maximum contraction, e.g., tetanic contraction, is thermally independent.〔Bennett, A.F., 1985. Temperature and muscle. ''J. Exp. Biol''.115, 333-344.〕 Muscles of some ectothermic species. e.g., sharks, show less thermal dependence at lower temperatures than endothermic species 〔Donley, J.M., Shadwick, R.E., Sepulveda, C.A., and Syme, D.A. 2007. Thermal dependence of contractile properties of the aerobic locomotor muscle in the leopard shark and the short fin mako shark. ''J. Exp. Biol.''210, 1194-1203.〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Q10 (temperature coefficient)」の詳細全文を読む スポンサード リンク
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