13C NMR of study of entrapping proteins (α-chymotrypsin) into reversed micelles of surfactants (aerosol OT) in organic solvents (n-octane)

1989 ◽  
Vol 54 (4) ◽  
pp. 1126-1134 ◽  
Author(s):  
Yurii E. Shapiro ◽  
Nikolai A. Budanov ◽  
Andrei V. Levashov ◽  
Nataliya L. Klyachko ◽  
Yurii L. Khmelnitsky ◽  
...  
Keyword(s):  
Relaxation Times ◽  
Fold Increase ◽  
Lattice Relaxation ◽  
Protein Molecule ◽  
Reversed Micelles ◽  
Spin Lattice Relaxation ◽  
Experimental Conditions ◽  
Aerosol Ot ◽  
Spin Lattice ◽  
Recovery Technique

Hydrated reversed micelles of Aerosol OT (AOT) in octane have been studied by 13C NMR spectroscopy. The changes of spin-lattice relaxation times (T1) for individual segments of the AOT molecule, induced by entrapping a protein (α-chymotrypsin) into the micelle, have been determined by the inversion-recovery technique. The dramatic (three-fold) increase of T1 found for the α-CH2 groups in the AOT molecules indicates that (unlike in the unfilled micelle) in the protein-containing micelle the boundary of the water cavity is shifted outward (0.5-0.7 nm, under the given experimental conditions), the alkyl chains of the surfactant being “flooded” by water molecules. This observation explains why the outer size of the reversed micelle does not change on insertion of a bulky protein molecule.

Bonded Hydrogen and Trapped H2 in a-Si1−xGex:H Alloys

1989 ◽  
Vol 149 ◽  
Author(s):  
E. J. Vanderheiden ◽  
G. A. Williams ◽  
P. C. Taylor ◽  
F. Finger ◽  
W. Fuhs
Keyword(s):  
Temperature Dependence ◽  
Molecular Hydrogen ◽  
Relaxation Times ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Spin Lattice ◽  
H Nmr ◽  
Local Environments

ABSTRACT1H NMR has been employed to study the local environments of bonded hydrogen and trapped molecular hydrogen (H2) in a series of a-Si1−xGex:H alloys. There is a monotonic decrease of bonded hydrogen with increasing x from ≈ 10 at. % at x = 0 (a-Si:H) to ≈ 1 at. % at x = 1 (a-Ge:H). The amplitude of the broad 1H NMR line, which is attributed to clustered bonded hydrogen, decreases continuously across the system. The amplitude of the narrow 1H NMR line, which is attributed to bonded hydrogen essentially randomly distributed in the films, decreases as x increases from 0 to ≈ 0.2. From x = 0.2 to x ≈ 0.6 the amplitude of the narrow 1H NMR line is essentially constant, and for x ≥ 0.6 the amplitude decreases once again. The existence of trapped H2 molecules is inferred indirectly by their influence on the temperature dependence of the spin-lattice relaxation times, T1. Through T1, measurements it is determined that the trapped H2 concentration drops precipitously between x = 0.1 and x = 0.2, but is fairly constant for 0.2 ≤ x ≤ 0.6. For a-Si:H (x = 0) the H2 concentration is ≈ 0.1 at. %, while for x ≥ 0.2 the concentration of H2 is ≤ 0.02 at. %.

Water-Saturated Mesoporous MCM-41 Systems Characterized by 1H NMR Spin-Lattice Relaxation Times

1995 ◽  
Vol 99 (12) ◽  
pp. 4148-4154 ◽  
Author(s):  
Eddy Walther Hansen ◽  
Ralf Schmidt ◽  
Michael Stoecker ◽  
Duncan Akporiaye
Keyword(s):  
1H Nmr ◽  
Relaxation Times ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Spin Lattice ◽  
Water Saturated ◽  
Mcm 41

A longitudinally detected high-field ESR spectrometer for the measurement of spin–lattice relaxation times

2004 ◽  
Vol 167 (2) ◽  
pp. 221-227 ◽  
Author(s):  
Ferenc Murányi ◽  
Ferenc Simon ◽  
Ferenc Fülöp ◽  
András Jánossy
Keyword(s):  
High Field ◽  
Relaxation Times ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Spin Lattice ◽  
High Field Esr
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