Insight into the effect mechanism of urea-induced protein denaturation by dielectric spectroscopy

2017 ◽  
Vol 19 (47) ◽  
pp. 32007-32015 ◽  
Author(s):  
Cancan Zhang ◽  
Man Yang ◽  
Kongshuang Zhao

Dielectric relaxation spectroscopy was applied to study how urea affects the phase transition of a thermosensitive polymer, poly(N-isopropylacrylamide) (PNIPAM), which has been widely used as a protein model. The interaction mechanism of PNIPAM and urea in different concentration regions and the deduction of urea-induced protein denaturation mechanism was presented.

RSC Advances ◽  
2017 ◽  
Vol 7 (23) ◽  
pp. 13733-13741 ◽  
Author(s):  
Cancan Zhang ◽  
Zhen Zhen ◽  
Liyan Ma ◽  
Kongshuang Zhao

Two nonaqueous ionic liquid (IL) microemulsions (toluene/TX-100/[bmim][PF6] and [bmim][BF4]/TX-100/benzene) were studied by dielectric spectroscopy covering a wide frequency range (40 Hz to 110 MHz).


Soft Matter ◽  
2018 ◽  
Vol 14 (35) ◽  
pp. 7190-7203 ◽  
Author(s):  
Xinlu Zhou ◽  
Kongshuang Zhao

The effect of grafting density of poly(ethylene oxide) and dodecyl groups on the conformation of poly(acrylic acid) in solution was clarified by dielectric relaxation spectroscopy over a frequency range from 40 Hz to 110 MHz.


2015 ◽  
Vol 17 (34) ◽  
pp. 22115-22124 ◽  
Author(s):  
Sylwia Całus ◽  
Lech Borowik ◽  
Andriy V. Kityk ◽  
Manfred Eich ◽  
Mark Busch ◽  
...  

We report dielectric relaxation spectroscopy experiments on two rod-like liquid crystals of the cyanobiphenyl family (5CB and 6CB) confined in tubular nanochannels with 7 nm radius and 340 micrometer length in a monolithic, mesoporous silica membrane.


2014 ◽  
Vol 118 (13) ◽  
pp. 3750-3759 ◽  
Author(s):  
Marieke Füllbrandt ◽  
Elena Ermilova ◽  
Asad Asadujjaman ◽  
Ralph Hölzel ◽  
Frank F. Bier ◽  
...  

1990 ◽  
Vol 45 (2) ◽  
pp. 126-134
Author(s):  
E. Dachwitz

AbstractThe permittivity of the title solutions has been measured at frequencies between some MHz and 72 GHz at 20 °C. Polyvinyl pyrrolidone of relative molar mass ranging from 1200 to 360 000 has been used. Referring to the concentration of monomeric repeat units (x = 0.65 maximum) there is no significant chain length effect. The permittivity data are described in terms of discrete Debye type spectral components. Special attention is paid to the contributions ascribable to the solvents, which are discussed with respect to their solvation behaviour. This can be described by a three state solvent model as follows. Besides the "bulk" solvent a further contribution is found in any case which is due to loosely affected (slowed down) solvent. Moreover a part of the solvent appears to be tightly bound to the polymer at high concentrations. All the solvents considered show similar solvation properties, notwithstanding their different tendencies towards selfassociation.


2007 ◽  
Vol 60 (1) ◽  
pp. 6 ◽  
Author(s):  
Simon Schrödle ◽  
Gary Annat ◽  
Douglas R. MacFarlane ◽  
Maria Forsyth ◽  
Richard Buchner ◽  
...  

A study of the room-temperature ionic liquid N-methyl-N-ethylpyrrolidinium dicyanamide by dielectric relaxation spectroscopy over the frequency range 0.2 GHz ≤ ν ≤ 89 GHz has revealed that, in addition to the already known lower frequency processes, there is a broad featureless dielectric loss at higher frequencies. The latter is probably due to the translational (oscillatory) motions of the dipolar ions of the IL relative to each other, with additional contributions from their fast rotation.


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