Introduction

Energy storage and release in dielectric materials can be described on the basis of the charge trapping mechanism. Most phenomenological aspects have been recently rationalized in terms of the space charge model [1,2]. Dynamical aspects are studied here by performing Molecular Dynamics simulations. We show that an excess electron introduced into the sapphire lattice (α-Al2O3) can be trapped only at a limited number of sites. The energy gained by allowing the electron to localize in these sites is of the order of 4-5 eV, in good agreement with the results of the space charge model. Displacements of the neighboring ions due to the implanted charge are shown to be localized in a small region of about 5Å. Detrapping is observed at 250 K. The ionic displacements turn out to play an important role in modifying the potential landscape by lowering, in a dynamical way, the barriers that cause localization at low temperature.

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“…[15]. The mean square displacement also compared reasonably with experimental measurements at 300 K and 2170 K [17], as shown in Figs. 1 and 2.…”

Section: Shell Model and Details Of The Simulationsupporting

confidence: 73%

Molecular dynamics simulation of electron trapping in sapphire

Rambaut

Jaffrézic

et al. 1997

Journal of Applied Physics

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“…The nitrogen and oxygen atoms are respectively displayed in grey and white. The ¢gure was prepared with BOBSCRIPT [24]. sium ions does not signi¢cantly a¡ect the thermal transition stage.…”

Section: Heat-induced Unfolding Of Slt35mentioning

confidence: 99%

Binding of calcium in the EF‐hand of Escherichia coli lytic transglycosylase Slt35 is important for stability

Asselt

Dijkstra

1999

FEBS Letters

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The Escherichia coli lytic transglycosylase Slt35 contains a single metal ion-binding site that resembles EF-hand calcium-binding sites. The Slt35 EF-hand is only the second observation of such a domain in a prokaryotic protein. Two crystal structures at 2.1 A î resolution show that both Ca 2+ ions and Na + ions can bind to the EF-hand domain, but in subtly different configurations. Heat-induced unfolding studies demonstrate that Ca 2+ ions are preferentially bound, and that only Ca 2+ ions significantly increase the melting temperature of Slt35. This shows that the EF-hand calcium-binding domain is important for the stability of Slt35.z 1999 Federation of European Biochemical Societies.

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“…The diagram includes the di¡erence electron density contoured at 2c and calculated using data between 20^2.0 A î with the pro£avin molecule omitted from model. (Generated using the program MOLSCRIPT [32] with modi¢cations by R. Esnouf [33].) Fig.…”

Section: Crystallographic Studiesmentioning

confidence: 99%

X‐ray and spectrophotometric studies of the binding of proflavin to the S1 specificity pocket of human α‐thrombin

Conti

Rivetti

Wonacott³

et al. 1998

FEBS Letters

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Proflavin can be used to study the interactions of inhibitors and substrates with thrombin by monitoring the changes in the visible absorption spectrum that occur on dye displacement. We have used microspectrophotometric methods to investigate the binding of proflavin to crystals of an K K-thrombinhirugen complex and have determined the structure by X-ray crystallography. The proflavin molecule binds in the S1 pocket of the enzyme with one of the amino groups hydrogen bonded to the carboxylate of Asp-189 while the protonated ring nitrogen is hydrogen bonded to the carbonyl of Gly-219. This result indicates that the proflavin displacement assay can be used to specifically monitor the binding of inhibitors to the S1 pocket.z 1998 Federation of European Biochemical Societies.

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Introduction

Cited by 4 publications

References 0 publications

Molecular dynamics simulation of electron trapping in sapphire

Molecular dynamics simulation of electron trapping in sapphire

Binding of calcium in the EF‐hand of Escherichia coli lytic transglycosylase Slt35 is important for stability

X‐ray and spectrophotometric studies of the binding of proflavin to the S1 specificity pocket of human α‐thrombin

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