scholarly journals 2‘-Hydroxyl Proton Positions in Helical RNA from Simultaneously Measured Heteronuclear Scalar Couplings and NOEs

2006 ◽  
Vol 128 (26) ◽  
pp. 8372-8373 ◽  
Author(s):  
Jinfa Ying ◽  
Ad Bax
Keyword(s):  
Scalar Couplings ◽  
Hydroxyl Proton

scholarly journals THE CASE OF ASYMPTOTIC SUPERSYMMETRY

2013 ◽  
Vol 28 (14) ◽  
pp. 1350053 ◽  
Author(s):  
BRUCE L. SÁNCHEZ-VEGA ◽  
ILYA L. SHAPIRO
Keyword(s):  
Fixed Point ◽  
Renormalization Group ◽  
Gauge Coupling ◽  
High Energy ◽  
Systematic Investigation ◽  
Coupling Constants ◽  
Scalar Coupling ◽  
Asymptotic State ◽  
Stable Fixed Point ◽  
Scalar Couplings

We start systematic investigation for the possibility to have supersymmetry (SUSY) as an asymptotic state of the gauge theory in the high energy (UV) limit, due to the renormalization group running of coupling constants of the theory. The answer on whether this situation takes place or not, can be resolved by dealing with the running of the ratios between Yukawa and scalar couplings to the gauge coupling. The behavior of these ratios does not depend too much on whether gauge coupling is asymptotically free (AF) or not. It can be shown that the UV stable fixed point for the Yukawa coupling is not supersymmetric. Taking this into account, one can break down SUSY only in the scalar coupling sector. We consider two simplest examples of such breaking, namely N = 1 supersymmetric QED and QCD. In one of the cases one can construct an example of SUSY being restored in the UV regime.

The gauche Effect. A Theoretical Study of the Topomerization (Degenerate Racemization) and Tautomerization of Methoxide Ion Tautomer

1973 ◽  
Vol 51 (15) ◽  
pp. 2423-2432 ◽  
Author(s):  
Saul Wolfe ◽  
Luis M. Tel ◽  
I. G. Csizmadia
Keyword(s):  
Electronic State ◽  
Ground Electronic State ◽  
Conformational Transformation ◽  
Molecular Orbital Calculations ◽  
Rotational Angle ◽  
Electron Pairs ◽  
Hydroxyl Proton ◽  
Gauche Effect ◽  
Internuclear Distances ◽  
Relationship Of

Non-empirical double zeta quality molecular orbital calculations on −CH2OH as a function of the C—O bond length (r), the rotational angle about the C—O bond (θ), and the pyramidal angle at carbon [Formula: see text] are described. From the stretching potential curve, E(r), it is shown that dissociation of −CH2OH proceeds to give CH2 and OH−. The rotation–inversion surface, [Formula: see text], has two types of minima; in both cases the most favorable pyramidal angle at carbon is 105°. The lower minimum corresponds to a structure (the Y conformation) having the hydroxyl proton on the external bisector of the HCH angle. The higher minimum is 6.67 kcal/mol less stable and corresponds to a structure (the W conformation) having the hydroxyl proton on the internal bisector of the HCH angle. The relationship of these results to the gauche effect is discussed and it is noted that at certain internuclear distances the nuclear–nuclear repulsion term (Enucl) may overcome the tendency of adjacent electron pairs and polar bonds to exist preferentially in that conformation which has the maximum number of gauche interactions between these electron pairs or polar bonds.The topomerization of −CH2OH, i.e., the conformational transformation from one Y conformation into another, proceeds, via the W conformation as an intermediate, by two separate events, viz. rotation about the C—O bond, having a barrier of 10.58 kcal/mol, and pyramidal inversion at carbon, with a barrier of 20.52 kcal/mol. Some factors governing the relative importance of rotation and inversion in degenerate racemization are discussed.In its ground electronic state CH3O− is 22.18 kcal/mol more stable than −CH2OH. However, in the low-lying excited states all conformations of −CH2OH are stabilized relative to CH3O−. The most stable excited state structure of −CH2OH corresponds to the energy maximum for rotation–inversion of the ground electronic state.

Detection of Scalar Couplings Across NH···OP and OH···OP Hydrogen Bonds in a Flavoprotein

2000 ◽  
Vol 122 (38) ◽  
pp. 9289-9295 ◽  
Author(s):  
Frank Löhr ◽  
Stephen G. Mayhew ◽  
Heinz Rüterjans
Keyword(s):  
Hydrogen Bonds ◽  
Scalar Couplings

Multiple Refocusing in NMR Spectroscopy: Compensation of Pulse Imperfections by Scalar Couplings

ChemPhysChem ◽  
2004 ◽  
Vol 5 (11) ◽  
pp. 1750-1754 ◽  
Author(s):  
Jens Dittmer ◽  
Geoffrey Bodenhausen
Keyword(s):  
Nmr Spectroscopy ◽  
Scalar Couplings

Hydroxyl-proton resonance shifts for a range of aqueous sugar solutions

1980 ◽  
Vol 83 (1) ◽  
pp. 9-20 ◽  
Author(s):  
M.C.R. Symons ◽  
J.A. Benbow ◽  
J.M. Harvey
Keyword(s):  
Proton Resonance ◽  
Hydroxyl Proton

Transmission mechanisms of NMR long-range J(13C,19F) scalar couplings in 1-F,4-X-cubanes: a DFT and experimental study

2006 ◽  
Vol 104 (4) ◽  
pp. 485-492 ◽  
Author(s):  
RubéN H. Contreras ◽  
Ángel L. Esteban ◽  
Ernesto DÍez ◽  
Nicholas J. Head ◽  
Ernest W. Della
Keyword(s):  
Experimental Study ◽  
Long Range ◽  
Scalar Couplings ◽  
Transmission Mechanisms

Hydroxyl-Proton Hydrogen Bonding in the Heparin Oligosaccharide Arixtra in Aqueous Solution

2014 ◽  
Vol 118 (2) ◽  
pp. 482-491 ◽  
Author(s):  
Consuelo N. Beecher ◽  
Robert P. Young ◽  
Derek J. Langeslay ◽  
Leonard J. Mueller ◽  
Cynthia K. Larive
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Bonding ◽  
Hydroxyl Proton

Accelerated spin dynamics in NMR driven by homonuclear scalar couplings

2013 ◽  
Vol 563 ◽  
pp. 107-111 ◽  
Author(s):  
Christy George ◽  
N. Chandrakumar
Keyword(s):  
Spin Dynamics ◽  
Scalar Couplings
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