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Dynamic Information (dynamic + information)

Distribution by Scientific Domains

Chemistry	50%
Engineering	33%

Selected Abstracts

Effect of variable message signs on driver speed behavior on a section of expressway under adverse fog conditions,A driving simulator approach

JOURNAL OF ADVANCED TRANSPORTATION, Issue 1 2006
V. Ganesh Babu Kolisetty
Abstract Variable message signs (VMS) are used to provide dynamic information and one current application is to show different speed limits under different conditions. As speed is an important contributor to road accidents and also affects driver speed behavior, the present study focuses on how effective traffic advisory information is when helping drivers to divert from potentially dangerous conditions. Graphical representation of an Expressway section made it easy to isolate the effects of speed etc. by drivers with information provided through VMS under adverse fog conditions. Understanding and reacting to the VMS system by drivers is essential for its success. If drivers do not react by changing speed behavior then the VMS system will fail and further implementation may cease. In this paper an Analysis of Variance model, which is appropriate to the proposed experimental conditions, is used to study how subjects (drivers) will perceive provided information and also to find the effect of VMS on driver speed behavior on the simulated Expressway section. [source]

Simultaneous light and small-angle neutron scattering on aggregating concentrated colloidal suspensions

JOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 1 2003
Sara Romer
A new sample environment has been developed in order to perform light and small-angle neutron scattering (SANS) simultaneously on colloidal systems. The combination of SANS and diffusing wave spectroscopy (DWS) is of particular use in the high-concentration regime. DWS provides information on the local dynamic properties of the individual particles, whereas SANS gives access to the structural properties on similar length scales. The combination of both methods thus allows one to obtain structural and dynamic information over a very large range of length and time scales. Using this new setup, the onset of aggregation and the sol,gel transition in concentrated destabilized polystyrene sphere suspensions have been investigated. At the gel point, a dramatic change of the particle dynamics from diffusion to a subdiffusive arrested motion is observed. However, while the DWS measurements indicate that dramatic changes in the local dynamics occur over a long period, the SANS pattern quickly reaches its final appearance. The SANS experiments thus indicate that a fluid-like structure is arrested in the course of the gel formation. The data are found to be in good qualitative agreement with computer simulations. [source]

Time-resolved contrast-enhanced imaging with isotropic resolution and broad coverage using an undersampled 3D projection trajectory

MAGNETIC RESONANCE IN MEDICINE, Issue 2 2002
Andrew V. Barger
Abstract Time-resolved contrast-enhanced 3D MR angiography (MRA) methods have gained in popularity but are still limited by the tradeoff between spatial and temporal resolution. A method is presented that greatly reduces this tradeoff by employing undersampled 3D projection reconstruction trajectories. The variable density k -space sampling intrinsic to this sequence is combined with temporal k -space interpolation to provide time frames as short as 4 s. This time resolution reduces the need for exact contrast timing while also providing dynamic information. Spatial resolution is determined primarily by the projection readout resolution and is thus isotropic across the FOV, which is also isotropic. Although undersampling the outer regions of k -space introduces aliased energy into the image, which may compromise resolution, this is not a limiting factor in high-contrast applications such as MRA. Results from phantom and volunteer studies are presented demonstrating isotropic resolution, broad coverage with an isotropic field of view (FOV), minimal projection reconstruction artifacts, and temporal information. In one application, a single breath-hold exam covering the entire pulmonary vasculature generates high-resolution, isotropic imaging volumes depicting the bolus passage. Magn Reson Med 48:297,305, 2002. © 2002 Wiley-Liss, Inc. [source]

Resolution of ligand positions by site-directed tryptophan fluorescence in tear lipocalin

PROTEIN SCIENCE, Issue 2 2000
Oktay K. Gasymov
Abstract The lipocalin superfamily of proteins functions in the binding and transport of a variety of important hydrophobic molecules. Tear lipocalin is a promiscuous lipid binding member of the family and serves as a paradigm to study the molecular determinants of ligand binding. Conserved regions in the lipocalins, such as the G strand and the F-G loop, may play an important role in ligand binding and delivery. We studied structural changes in the G strand of holo- and apo-tear lipocalin using spectroscopic methods including circular dichroism analysis and site-directed tryptophan fluorescence. Apo-tear lipocalin shows the same general structural characteristics as holo-tear lipocalin including alternating periodicity of a ,-strand, orientation of amino acid residues 105, 103, 101, and 99 facing the cavity, and progressive depth in the cavity from residues 105 to 99. For amino acid residues facing the internal aspect of cavity, the presence of a ligand is associated with blue shifted spectra. The collisional rate constants indicate that these residues are not less exposed to solvent in holo-tear lipocalin than in apo-tear lipocalin. Rather the spectral blue shifts may be accounted for by a ligand induced rigidity in holo-TL. Amino acid residues 94 and 95 are consistent with positions in the F-G loop and show greater exposure to solvent in the holo- than the apo-proteins. These findings are consistent with the general hypothesis that the F-G loop in the holo-proteins of the lipocalin family is available for receptor interactions and delivery of ligands to specific targets. Site-directed tryptophan fluorescence was used in combination with a nitroxide spin labeled fatty acid analog to elucidate dynamic ligand interactions with specific amino acid residues. Collisional quenching constants of the nitroxide spin label provide evidence that at least three amino acids of the G strand residues interact with the ligand. Stern-Volmer plots are inconsistent with a ligand that is held in a static position in the calyx, but rather suggest that the ligand is in motion. The combination of site-directed tryptophan fluorescence with quenching by nitroxide labeled species has broad applicability in probing specific interactions in the solution structure of proteins and provides dynamic information that is not attainable by X-ray crystallography. [source]

Experiments in Associative Urbanism

ARCHITECTURAL DESIGN, Issue 4 2009
Tom Verebes
Abstract ,There has never been a more crucial time to challenge, reassess and propose alternatives to conventional urban masterplanning and its associated conventions, types and standards.' Tom Verebes describes how the Design Research Laboratory (DRL) at the Architectural Association in London has employed a parametric approach to urbanism that investigates how associative design systems can control local dynamic information flows through interactive systems, spaces and interfaces. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Electrochemical Characterization of (ZnO/dsDNA)n Layer-by-layer Films and Detection of Natural DNA Oxidative Damage

CHINESE JOURNAL OF CHEMISTRY, Issue 10 2009
Meng Du
Abstract The positively charged nano-ZnO and negatively charged natural DNA were alternately adsorbed on the surface of a gold electrode, forming (ZnO/dsDNA)nlayer-by-layer films. Valuable dynamic information for controlling the formation and growth of the films was obtained by cyclic voltammetry and electrochemical impedance spectroscopy. Differential pulse voltammetric (DPV) measurements showed that the electroactive probe methylene blue (MB) could be loaded in the (ZnO/dsDNA)nfilms from its solution, and then released from the films into Britton-Robinson (B-R) buffer. The complete reloading of MB in the films could be realized by immersing the films in MB solution again. However, after incubation in the solution of carcinogenic metal nickel, the damaged (ZnO/dsDNA)n films could not return to their original and fully-loaded state, and showed smaller DPV peak currents. The results demonstrated that the DNA damage induced by the hydroxyl radical could be achieved by electrochemistry. [source]