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Internal Mobility (internal + mobility)

Distribution by Scientific Domains

Chemistry	50%

Selected Abstracts

Tris(8-hydroxyquinoline-5-sulfonate)aluminum Intercalated Mg,Al Layered Double Hydroxide with Blue Luminescence by Hydrothermal Synthesis

ADVANCED FUNCTIONAL MATERIALS, Issue 17 2010
Shuangde Li
Abstract Blue luminescent hybrid materials (DDS,AQS(x%)/LDH) are successfully prepared by co-intercalating tris(8-hydroxyquinoline-5-sulfonate)aluminum anions (AQS3,) and dodecyl sulfonate (DDS,) with different molar ratios into Mg,Al layered double hydroxides (LDHs) by the hydrothermal and solution co-precipitation methods. A film of the material on a quartz substrate is obtained by the solvent evaporation method. The results show the blue luminescence is remarkably different from the pristine Na3AQS, which has cyan luminescence (ca. 450,470 nm vs. 495 nm). Furthermore, the hydrothermal product of DDS,AQS(66.67%)/LDH exhibits optimal luminous intensity and a significantly enhanced fluorescence lifetime. Nuclear magnetic resonance and Fourier-transform infrared spectroscopy indicate that the cyan,blue luminescence transition is due to the isomerization of meridianal to facial AQS via ligand flip caused by a host,guest electrostatic interaction, in combination with the dispersion and pre-intercalation effect of DDS. The hydrothermal conditions can promote a more ordered alignment of the intercalated fac -AQS compared with alignment in the solution state, and the rigid LDHs environment can confine the internal mobility of AQS to keep the facial configuration stable. This stability allows a facile preparation of large amounts of blue luminous powder/film, which is a new type of inorganic,organic hybrid photofunctional material. [source]

The response of internal dynamics to hydrophobic core mutations in the SH3 domain from the Fyn tyrosine kinase

PROTEIN SCIENCE, Issue 4 2004
Anthony Mittermaier
Abstract We have used 15N- and 2H-NMR spin relaxation experiments to study the response of backbone and side-chain dynamics when a leucine or valine is substituted for a completely buried phenylalanine residue in the SH3 domain from the Fyn tyrosine kinase. Several residues show differences in the time scales and temperature dependences of internal motions when data for the three proteins are compared. Changes were also observed in the magnitude of dynamics, with the valine, and to a lesser extent leucine mutant, showing enhanced flexibility compared to the wild-type (WT) protein. The motions of many of the same amide and methyl groups are affected by both mutations, identifying a set of loci where dynamics are sensitive to interactions involving the targeted side chain. These results show that contacts within the hydrophobic core affect many aspects of internal mobility throughout the Fyn SH3 domain. [source]

Modelling recruitment training in mathematical human resource planning

APPLIED STOCHASTIC MODELS IN BUSINESS AND INDUSTRY, Issue 1 2002
A. C. Georgiou
Abstract This paper deals with mathematical human resource planning; more specifically, it suggests a new model for a manpower-planning system. In general, we study a k -classed hierarchical system where the workforce demand at each time period is satisfied through internal mobility and recruitment. The motivation for this work is based on various European Union incentives, which promote regional or local government assistance programs that could be exploited by firms not only for hiring and training newcomers, but also to improve the skills and knowledge of their existing personnel. In this respect, in our augmented mobility model we establish a new ,training/standby' class, which serves as a manpower inventory position for potential recruits. This class, which may very well be internal or external to the system, is incorporated into the framework of a non-homogeneous Markov chain model. Furthermore, cost objectives are employed using the goal-programming approach, under different operating assumptions, in order to minimize the operational cost in the presence of system's constraints and regulations. Copyright © 2002 John Wiley & Sons, Ltd. [source]

Molecular dynamics simulations of HPr under hydrostatic pressure

BIOPOLYMERS, Issue 5 2004
Muriel Canalia
Abstract The histidine-containing protein (HPr) plays an important role in the phosphotransferase system (PTS). The deformations induced on the protein structure at high hydrostatic pressure values (4, 50, 100, 150, and 200 MPa) were previously (H. Kalbitzer, A. Görler, H. Li, P. Dubovskii, A. Hengstenberg, C. Kowolik, H. Yamada, and K. Akasaka, Protein Science 2000, Vol. 9, pp. 693,703) analyzed by NMR experiments: the nonlinear variations of the amide chemical shifts at high pressure values were supposed to arise from induced shifts in the protein conformational equilibrium. Molecular dynamics (MD) simulations are here performed, to analyze the protein internal mobility at 0.1 MPa, and to relate the nonlinear variations of chemical shifts observed at high pressure, to variations in conformational equilibrium. The global features of the protein structure are only slightly modified along the pressure. Nevertheless, the values of the Voronoi residues volumes show that the residues of ,-helices are more compressed that those belonging to the ,-sheet. The ,-helices are also displaying the largest internal mobility and deformation in the simulations. The nonlinearity of the 1H chemical shifts, computed from the MD simulation snapshots, is in qualitative agreement with the nonlinearity of the experimentally observed chemical shifts. © 2004 Wiley Periodicals, Inc. Biopolymers 2004 [source]