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Effects of Aging on Feedforward Postural Synergies

100%
Asaka T., Wang Y.
Journal of Human Kinetics
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2008
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vol. 20
63-70
EN
We investigated the effects of aging on postural muscles covariate patterns prior to voluntary perturbations. Nine healthy young and nine older subjects were instructed to release a load in a self-paced manner. The results of cross-correlation analyses showed that the average time lag corresponding peak correlation coefficient between trunk flexor and extensor muscles in the older group was significantly shorter, compared to that in the young group. The results of principal component analysis showed that the co-contraction Muscle-modes in the older group were observed more frequently than those in the young group. These results indicate that the older group showed changes in the anticipatory postural muscle co-variation, suggesting the transition from reciprocal to co-activation pattern with aging.
2
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Extraction of trace acetylspiramycin in real aqueous environments using aqueous two-phase system of ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate and phosphate

81%
Wang Y., Han J., Xie X.-q., Li C.-x.
Open Chemistry
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2010
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vol. 8
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issue 6
1185-1191
EN
The partitioning of acetylspiramycin was carried out in an aqueous two-phase system (ATPS) formed by a hydrophilic ionic liquid (1-butyl-3-methylimidazolium tetrafluoraborate, [Bmim]BF4) and NaH2PO4. This ATPS is a simple, non-toxic and effective sample pretreatment technique, which was developed for the simultaneous separation, enrichment and rapid analysis of acetylspiramycin coupled with molecular fluorescence spectrophotometry. Analysis of the liquid-liquid equilibrium of [Bmim]BF4-salt ATPS demonstrated that the salting-out ability of different salts may be related to the Gibbs energy of hydration of the ions. The effects of types of salts, concentration of NaH2PO4, and temperature were analysed. Under optimum conditions, the average extraction efficiency and partition coefficient were 90.14% and 91.1, respectively. Thermodynamic functions provide some information about the molecular mechanism involved in acetylspiramycin transfer to the top phase, suggesting an important acetylspiramycin-[Bmim]BF4 interaction. The method yielded a linear range in the concentration from 1.0 to 10.0 µg mL−1 of acetylspiramycin, and the limit of detection was 0.02 µg mL−1. This method could be successfully applied for the analysis of acetylspiramycin in lake water, river water and groundwater. The proposed extraction technique appears to be suitable as a first step for the separation of macrolide antibiotics from real aqueous environments.
3
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Liquid-liquid equilibrium of novel aqueous two-phase systems and evaluation of salting-out abilities of salts

71%
Wang Y., Wang J., Han J., Hu S., Yan Y.
Open Chemistry
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2010
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vol. 8
|
issue 4
886-891
EN
Binodal data are beneficial to the design of aqueous two-phase extraction and the establishment of thermodynamic models. For the 2-propanol + Li2SO4/Na2SO4/ (NH4)2SO4/K3PO4 + water systems and 1-propanol + K3PO4/K3C6H5O7/(NH4)3C6H5O7 + water systems, binodal data were determined at 298.15 K. The binodal data were correlated by a theoretical equation on the basis of statistical geometry. The salting-out abilities of salts and the phase-separation abilities of alcohols were evaluated by the effective excluded volume of salt and the binodal curves plotted in molality. A simple Hofmeister series of cations and anions were obtained. The organic salt, K3C6H5O7, shows as high a salting-out ability as K3PO4. [...]
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