Dynamic properties of the active site of azurin studied by the temperature dependence of the optical spectrum

1990 ◽  
Vol 3 (2) ◽  
pp. 77-79 ◽  
Author(s):  
Antonio Cupane ◽  
Maurizio Leone ◽  
Eugenio Vitrano ◽  
Lorenzo Cordone
Keyword(s):  
Temperature Dependence ◽  
Active Site ◽  
Optical Spectrum ◽  
Dynamic Properties

Temperature Dependence of Dynamic Properties of Elastomers. Relaxation Distributions

1952 ◽  
Vol 25 (4) ◽  
pp. 720-729 ◽  
Author(s):  
John D. Ferry ◽  
Edwin R. Fitzgerald ◽  
Lester D. Grandine ◽  
Malcolm L. Williams
Keyword(s):  
Distribution Function ◽  
Temperature Dependence ◽  
Dynamic Properties ◽  
Relaxation Times ◽  
Dynamic Mechanical Properties ◽  
Relaxation Processes ◽  
The Real ◽  
Reduced Frequency ◽  
Dynamic Rigidity ◽  
Composite Curve

Abstract By the use of reduced variables, the temperature dependence and frequency dependence of dynamic mechanical properties of rubberlike materials can be interrelated without any arbitrary assumptions about the functional form of either The definitions of the reduced variables are based on some simple assumptions regarding the nature of relaxation processes. The real part of the reduced dynamic rigidity, plotted against the reduced frequency, gives a single composite curve for data over wide ranges of frequency and temperature; this is true also for the imaginary part of the rigidity or the dynamic viscosity. The real and imaginary parts of the rigidity, although independent measurements, are interrelated through the distribution function of relaxation times, and this relation provides a check on experimental results. First and second approximation methods of calculating the distribution function from dynamic data are given. The use of the distribution function to predict various types of time-dependent mechanical behavior is illustrated.

scholarly journals The Dynamic Properties of 5Cb Filled with Aerosil Particles Investigated by Pcs

1999 ◽  
Vol 559 ◽  
Author(s):  
F.M. Aliev ◽  
M. Kreuzer ◽  
Yu.P. Panarin
Keyword(s):  
Liquid Crystal ◽  
Temperature Dependence ◽  
Relaxation Process ◽  
Nematic Liquid Crystal ◽  
Broad Spectrum ◽  
Dynamic Properties ◽  
Relaxation Times ◽  
Correlation Spectroscopy ◽  
Relaxation Processes ◽  
Optoelectronic Application

ABSTRACTNematic liquid crystal filled with Aerosil particles, a prospective composite material for optoelectronic application, has been investigated by static light scattering and Photon Correlation Spectroscopy (PCS). The Aerosil particles in filled nematic liquid crystals (FN) form a network structure with LC domains about 2500 Å in size with a random distribution of the director orientation of each domain.We found that the properties of 5CB are considerably affected by the network. The N-I phase transition in filled 5CB was found to be smeared out and depressed. PCS experiments show that two new relaxation processes appear in filled 5CB in addition to the director fluctuation process in bulk. The slow relaxation process, with a broad spectrum of relaxation times, is somewhat similar to the slow decay, which is observed in confined nematic liquid crystal.The middle frequency process was assigned to the director fluctuations in the surface layer formed at the particle-LC interface. The decay function describing this relaxation process is a stretched exponential (β ≍ 0.7). The temperature dependence of the relaxation times of the middle frequency obeys the Vogel-Rilcher law. Such a temperature dependence, accompanied by a broad spectrum of relaxation times suggests that the dynamics of the director fluctuations near the Aerosil particle-LC interface is glass-like.

On the Temperature Dependence of the Optical Spectrum of Cu2+Ions Doped in ND4Cl(Basic) and NH4Cl(Acidic) Crystals

1986 ◽  
Vol 55 (11) ◽  
pp. 4068-4073 ◽  
Author(s):  
J. Lakshmana Rao ◽  
Asako Kawamori ◽  
Katsumi Miyazaki ◽  
Keisuke Suzuki
Keyword(s):  
Temperature Dependence ◽  
Optical Spectrum

Single Shockley Stacking Faults in As-Grown 4H-SiC Epilayers

2010 ◽  
Vol 645-648 ◽  
pp. 327-330 ◽  
Author(s):  
Jawad ul Hassan ◽  
Peder Bergman
Keyword(s):  
Temperature Dependence ◽  
Optical Microscopy ◽  
Optical Spectrum ◽  
Carrier Lifetime ◽  
Geometrical Structure ◽  
Stacking Faults ◽  
Stacking Fault ◽  
Structural Defects ◽  
Forward Voltage ◽  
Substrate Interface

An extended structural defects which locally drastically reduces the carrier lifetime, has been observed in as-grown epilayers. A combination of back polishing, etching in molten KOH and optical microscopy revealed the geometrical structure of the stacking fault inside the epilayer. The fault started close to the epi-substrate interface, expanded initially rapidly but changed geometry after some time and reduced in size during further growth. The optical spectrum as well as the temperature dependence from this fault is identical to the emission from the single Shockley stacking faults previously only observed and formed in the bipolar diodes during forward voltage operation.

scholarly journals Chemical mapping exposes the importance of active site interactions in governing the temperature dependence of enzyme turnover

2021 ◽  
Author(s):  
Samuel D Winter ◽  
Hannah BL Jones ◽  
Dora Rasadean ◽  
Rory Crean ◽  
Michael J. Danson ◽  
...  
Keyword(s):  
Heat Capacity ◽  
Temperature Dependence ◽  
Protein Dynamics ◽  
Active Site ◽  
Glucose Dehydrogenase ◽  
Global Changes ◽  
Global Dynamics ◽  
Specific Substrate ◽  
Substrate Interactions ◽  
Enzyme Turnover

Uncovering the role of global protein dynamics in enzyme turnover is needed to fully understand enzyme catalysis. Recently, we have demonstrated that the heat capacity of catalysis can reveal links between the protein free energy landscape, global protein dynamics and enzyme turnover, suggesting that subtle changes molecular interactions at the active site can affect long range protein dynamics and link to enzyme temperature activity. Here we use a model promiscuous enzyme (Glucose dehydrogenase from Sulfolobus Solfataricus) to chemically map how individual substrate interactions affect the temperature dependence of enzyme activity and the network of motions throughout the protein. Utilizing a combination of kinetics, REES spectroscopy and computational simulation we explore the complex relationship between enzyme-substrate interactions and the global dynamics of the protein. We find that changes in the heat capacity of catalysis and protein dynamics can be mapped to specific substrate-enzyme interactions. Our study reveals how subtle changes in substrate binding affect global changes in motion and flexibility extending throughout the protein.

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