Results 11 to 20 of about 196 (190)
Proceedings of the Royal Society B: Biological Sciences, 2009 Ratcheting surfaces are a common motif in nature and appear in plant awns and grasses. They are known to proffer selective advantages for seed dispersion and burial. In two simple model experiments, we show that these anisotropically toothed surfaces naturally serve as motion rectifiers and generically move in a unidirectional manner, when subjected to
KULIC, IM +4 more
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Physical Review Letters, 1997 Summary: We investigate quantum Brownian motion in adiabatically rocked ratchet systems. Above a crossover temperature \(T_c\) tunneling events are rare, yet they already substantially enhance the classical particle current. Below \(T_c\), quantum tunneling prevails and the classical predictions grossly underestimate the transport. Upon approaching \(T=
Reimann, Peter +2 more
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Nature Reviews Chemistry, 2023 Synthetic chemistry has traditionally relied on reactions between reactants of high chemical potential and transformations that proceed energetically downhill to either a global or local minimum (thermodynamic or kinetic control). Catalysts can be used to manipulate kinetic control, lowering activation energies to influence reaction outcomes.
Stefan Borsley +3 more
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EPL (Europhysics Letters), 2009 We present a generic formalism to describe Brownian motion of particles with intrinsic asymmetry and give predictions for the drift behavior in unbiased time-dependent force fields. Our findings are supported by molecular dynamics simulations.
Broek, M. van den +2 more
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Ratcheting up the ratchet: on the evolution of cumulative culture [PDF]
Philosophical Transactions of the Royal Society B: Biological Sciences, 2009 Some researchers have claimed that chimpanzee and human culture rest on homologous cognitive and learning mechanisms. While clearly there are some homologous mechanisms, we argue here that there are some different mechanisms at work as well. Chimpanzee cultural traditions represent behavioural biases of different populations, all within the species ...
Claudio, Tennie +2 more
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Cancer Cell, 2008 In this issue of Cancer Cell, Murphy et al. describe a mouse model designed to examine the biological effects of different levels of deregulated c-myc expression. They provide evidence that distinct threshold levels of Myc are required for increased proliferation and for apoptosis in different tissues.
Freie, Brian W., Eisenman, Robert N.
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Ferrofluids as Thermal Ratchets [PDF]
Physical Review Letters, 2003 Colloidal suspensions of ferromagnetic nano-particles, so-called ferrofluids, are shown to be suitable systems to demonstrate and investigate thermal ratchet behavior: By rectifying thermal fluctuations, angular momentum is transferred to a resting ferrofluid from an oscillating magnetic field without net rotating component.
Engel, A +3 more
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Confined Brownian ratchets [PDF]
The Journal of Chemical Physics, 2013 We analyze the dynamics of Brownian ratchets in a confined environment. The motion of the particles is described by a Fick-Jakobs kinetic equation in which the presence of boundaries is modeled by means of an entropic potential. The cases of a flashing ratchet, a two-state model, and a ratchet under the influence of a temperature gradient are analyzed ...
Malgaretti, Paolo +2 more
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