Postural reflex activity during unperceived perturbation of standing was investigated in 38 elderly subjects (70-96 years old) and 10 younger adults (19-48 years old), and it was related in the elderly group to a history of unexplained falling in the 12 months prior to testing. Ankle torque (T) and ankle angle (A) were recorded during unperceived forward pulls to obtain the ankle stiffness (DeltaT/DeltaA), providing a measure of postural reflex activity at the ankle. Elderly nonfallers and younger adults had similar ranges of normalized ankle reflex stiffness. High ankle stiffness was significantly more common in elderly multiple fallers than in elderly nonfallers (p =.018). Furthermore, a majority of unstable elderly subjects who had reported a single unexplained fall also had unusually high ankle stiffness (p =.004). Multiple fallers and unstable subjects tended to overshoot backward on pull release in comparison with nonfallers (p =.003), which is suggestive of an overactive reflex response that might contribute to postural instability.
Two replica exchange molecular dynamics (REMD) simulations were carried out to study the thermodynamics of a 20-residue Trp-cage folding based on a newly developed polarized protein-specific charge (PPC). Starting from a fully extended conformation, Trp-cage native conformation was successfully sampled using REMD based on a 3-step PPC update. Next, the obtained Trp-cage folded conformation was then used to calculate the PPC in which another REMD was performed to explore the thermodynamic stability of Trp-cage. The theoretical melting temperature T m of &325 K was found to be in close agreement with experimental melting temperature, T m of 315 K. This indicates that the PPC was correctly predicting the temperature dependence. The current study provides a direct proof of how electrostatic polarization affects protein folding.
Densely installed advertising signs have become a common source of light pollution in Asian countries. Due to mixed land use, there is a question as to whether or not the sign luminance limits set by the CIE are effective in preventing light trespass from these signs. Light trespass from advertising signs was comprehensively analysed by field measurements and software simulations. The results show that, in Taiwan, although the luminances of almost all of the signs are much lower than the limit set by the CIE, they still cause serious light trespass due to their large coverage area, high density distribution and improper installation. From an urban planning point of view, control policies are recommended as models for other countries with similar environmental problems.
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