scholarly journals α and β relaxation dynamics of a fragile plastic crystal

2006 ◽  
Vol 124 (12) ◽  
pp. 124911 ◽  
Author(s):  
L. C. Pardo ◽  
P. Lunkenheimer ◽  
A. Loidl
Keyword(s):  
Plastic Crystal ◽  
Relaxation Dynamics ◽  
Β Relaxation

scholarly journals Effects of pressure on the dynamics of an oligomeric protein from deep-sea hyperthermophile

2015 ◽  
Vol 112 (45) ◽  
pp. 13886-13891 ◽  
Author(s):  
Utsab R. Shrestha ◽  
Debsindhu Bhowmik ◽  
John R. D. Copley ◽  
Madhusudan Tyagi ◽  
Juscelino B. Leão ◽  
...  
Keyword(s):  
Hydrothermal Vents ◽  
Ambient Pressure ◽  
Inorganic Pyrophosphatase ◽  
Relaxation Dynamics ◽  
Egg White Lysozyme ◽  
Protein Energy ◽  
Oligomeric Protein ◽  
Model Protein ◽  
Quasielastic Neutron ◽  
Β Relaxation

Inorganic pyrophosphatase (IPPase) from Thermococcus thioreducens is a large oligomeric protein derived from a hyperthermophilic microorganism that is found near hydrothermal vents deep under the sea, where the pressure is up to 100 MPa (1 kbar). It has attracted great interest in biophysical research because of its high activity under extreme conditions in the seabed. In this study, we use the quasielastic neutron scattering (QENS) technique to investigate the effects of pressure on the conformational flexibility and relaxation dynamics of IPPase over a wide temperature range. The β-relaxation dynamics of proteins was studied in the time ranges from 2 to 25 ps, and from 100 ps to 2 ns, using two spectrometers. Our results indicate that, under a pressure of 100 MPa, close to that of the native environment deep under the sea, IPPase displays much faster relaxation dynamics than a mesophilic model protein, hen egg white lysozyme (HEWL), at all measured temperatures, opposite to what we observed previously under ambient pressure. This contradictory observation provides evidence that the protein energy landscape is distorted by high pressure, which is significantly different for hyperthermophilic (IPPase) and mesophilic (HEWL) proteins. We further derive from our observations a schematic denaturation phase diagram together with energy landscapes for the two very different proteins, which can be used as a general picture to understand the dynamical properties of thermophilic proteins under pressure.

scholarly journals Relaxation dynamics and ionic conductivity in a fragile plastic crystal

2010 ◽  
Vol 133 (14) ◽  
pp. 144509 ◽  
Author(s):  
Th. Bauer ◽  
M. Köhler ◽  
P. Lunkenheimer ◽  
A. Loidl ◽  
C. A. Angell
Keyword(s):  
Ionic Conductivity ◽  
Plastic Crystal ◽  
Relaxation Dynamics

scholarly journals Interplay of α/β-Relaxation Dynamics and the Shape of Ionomer Building Blocks

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Bruno R. Matos ◽  
Rodolfo Politano ◽  
José Fernando Q. Rey ◽  
Daniel Hermida-Merino ◽  
Ulrich Schade ◽  
...  
Keyword(s):  
Building Blocks ◽  
Relaxation Dynamics ◽  
Β Relaxation

Relaxation dynamics in confined glasses

2000 ◽  
Vol 10 (PR7) ◽  
pp. Pr7-227-Pr7-232 ◽  
Author(s):  
B. Jérôme ◽  
E. Cecchetto ◽  
N. R. de Souza ◽  
A. L. Demirel
Keyword(s):  
Relaxation Dynamics

Features of radiothermoluminescence of polypropylene and ethylene propylenediene elastomer SKEPT-4044 compositions with nanoscale metal-containing fillers

2020 ◽  
pp. 66-73
Author(s):  
A.M. Magerramov ◽  
◽  
N.I. Kurbanova ◽  
M.N. Bayramov ◽  
N.A. Alimirzoyeva ◽  
...  
Keyword(s):  
Transition Temperature ◽  
Molecular Mobility ◽  
Fe3o4 Nanoparticles ◽  
Low Temperatures ◽  
Frost Resistance ◽  
Relaxation Processes ◽  
Ethylene Propylene ◽  
Temperature Range ◽  
Β Relaxation

Using radiothermoluminescence (RTL), the molecular mobility features in the temperature range of 77-300 K were studied for the polypropylene (PP)/ethylene propylene diene elastomer SKEPT-4044 with NiO, Cu2O and Fe3O4 nanoparticles (NPs) based on ABS-acrylonitrile butadiene or SCS-divinyl styrene matrices. It has been shown that the introduction of nanofillers in PP significantly affects the nature and temperature of γ- and β-relaxation processes, while the region of manifestation of the β-process noticeably shifts to the region of low temperatures. Composites with Cu2O NPs have a higher β-transition temperature Tβ than composites with other NPs. It was found that PP/SKEPT-4044 composites with Cu2O NPs with a dispersion of 11-15 nm and acrylonitrile butadiene thermoplastics have optimal frost resistance compared to other compositions.

Electron phonon relaxation dynamics of superconducting niobium as a function of temperature

1992 ◽  
Author(s):  
Margarita Mihailidi ◽  
Qirong Xing ◽  
Kwong M. Yoo ◽  
Robert R. Alfano
Keyword(s):  
Relaxation Dynamics
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