A29Si NMR study of natural and synthetic melanophlogites, the silica analogues of the clathrate hydrates of type I

1990 ◽  
Vol 8 (1-2) ◽  
pp. 235-239 ◽  
Author(s):  
C. A. Fyfe ◽  
H. Gies
Keyword(s):  
Clathrate Hydrates ◽  
Type I ◽  
Nmr Study ◽  
Natural And Synthetic

2H and13C NMR study of guest molecule orientation in clathrate hydrates

1984 ◽  
Vol 2 (1-2) ◽  
pp. 239-247 ◽  
Author(s):  
D. W. Davidson ◽  
C. I. Ratcliffe ◽  
J. A. Ripmeester
Keyword(s):  
Guest Molecule ◽  
Clathrate Hydrates ◽  
Nmr Study

A Simple Method for Calculation of the Composition of Type I Clathrate Hydrates

2012 ◽  
Vol 638 (3-4) ◽  
pp. 648-651
Author(s):  
László Kótai ◽  
Szabolcs Bálint ◽  
István Gács ◽  
Györgyi Lakatos ◽  
András Angyal ◽  
...  
Keyword(s):  
Clathrate Hydrates ◽  
Type I ◽  
Simple Method

Effect of a hydrophobic amino acid at position (i −1) on the stability of β-turns in hydrophilic pentapeptides as studied by NMR and molecular mechanics

1995 ◽  
Vol 73 (7) ◽  
pp. 972-980
Author(s):  
Xiaohong Liu ◽  
Serafin Fraga ◽  
Albin Otter ◽  
George Kotovych ◽  
Paul G. Scott
Keyword(s):  
Amino Acid ◽  
Molecular Mechanics ◽  
Ideal Type ◽  
Type I ◽  
Hydrophobic Amino Acid ◽  
Molecular Mechanics Calculations ◽  
Nmr Data ◽  
Nmr Study ◽  
Protected Tetrapeptide ◽  
The Stability

A detailed NMR study of the peptide NAc-FDEKA-NH2 in aqueous and in CD3OH/H2O solutions as well as the N-acetylpentapeptide amides YDEKA, VDEKA, GDEKA, and the protected tetrapeptide NAc-DEKA-NH2 in methanolic solutions indicates the importance of the first amino acid (at i −1) on stabilizing the type I β-turn. The data illustrate the hydrophobic stabilization of this turn, which is present in FDEKA, YDEKA, and VDEKA. For GDEKA and DEKA, the NMR data indicate that this turn is not present. Molecular mechanics calculations support this conclusion and indicate that for FDEKA and GDEKA the type I β-turn is distorted in both the vacuum and the solvated structures. For the solvated structures, the Cα(i) − Cα(i + 3) distance is 4.87 Å for FDEKA and 6.00 Å for GDEKA, which are to be compared with the value of 4.64 Å for an ideal type I β-turn, i.e., the distortion is far greater in GDEKA than in FDEKA. The calculations can be interpreted to indicate the presence of two major conformations in solution. Keywords: β-turns, FDEKA, pentapeptide.

A 13C solid-state NMR study of the structure and auto-oxidation process of natural and synthetic melanins

1994 ◽  
Vol 1204 (1) ◽  
pp. 19-27 ◽  
Author(s):  
Muriel Hervé ◽  
Jérôme Hirschinger ◽  
Pierre Granger ◽  
Patrick Gilard ◽  
André Deflandre ◽  
...  
Keyword(s):  
Solid State ◽  
Solid State Nmr ◽  
Oxidation Process ◽  
Nmr Study ◽  
Natural And Synthetic

Theoretical studies on microstructures, stabilities and formation conditions of some sour gas in the type I, II, and H clathrate hydrates

2018 ◽  
Vol 1153 ◽  
pp. 292-298
Author(s):  
Xuran Zhang ◽  
Nianxiang Qiu ◽  
Qing Huang ◽  
Xianhu Zha ◽  
Jian He ◽  
...  
Keyword(s):  
Clathrate Hydrates ◽  
Type I ◽  
Theoretical Studies ◽  
Formation Conditions ◽  
Sour Gas

Thermodynamic stability of type-I and type-II clathrate hydrates depending on the chemical species of the guest substances

2007 ◽  
Vol 126 (23) ◽  
pp. 234506 ◽  
Author(s):  
Tatsuya Miyoshi ◽  
Masatoshi Imai ◽  
Ryo Ohmura ◽  
Kenji Yasuoka
Keyword(s):  
Thermodynamic Stability ◽  
Chemical Species ◽  
Clathrate Hydrates ◽  
Type I ◽  
Type Ii
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