RATE OF ELIMINATION OF WATER MOLECULES FROM THE FIRST COÖRDINATION SPHERE OF PARAMAGNETIC CATIONS AS DETECTED BY NUCLEAR MAGNETIC RESONANCE MEASUREMENTS OF O17 1

1961 ◽  
Vol 65 (11) ◽  
pp. 2075-2077 ◽  
Author(s):  
Robert E. Connick ◽  
E. Diane Stover
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Coordination Sphere ◽  
Water Molecules ◽  
Nuclear Magnetic

scholarly journals A nuclear magnetic resonance study of water in aggrecan solutions

2016 ◽  
Vol 3 (3) ◽  
pp. 150705 ◽  
Author(s):  
Richard J. Foster ◽  
Robin A. Damion ◽  
Thomas G. Baboolal ◽  
Stephen W. Smye ◽  
Michael E. Ries
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Relaxation Rate ◽  
Activation Energies ◽  
Proton Nuclear Magnetic Resonance ◽  
Water Molecules ◽  
Transverse Relaxation Rate ◽  
Relaxation Rates ◽  
Transverse Relaxation ◽  
Nuclear Magnetic

Aggrecan, a highly charged macromolecule found in articular cartilage, was investigated in aqueous salt solutions with proton nuclear magnetic resonance. The longitudinal and transverse relaxation rates were determined at two different field strengths, 9.4 T and 0.5 T, for a range of temperatures and aggrecan concentrations. The diffusion coefficients of the water molecules were also measured as a function of temperature and aggrecan concentration, using a pulsed field gradient technique at 9.4 T. Assuming an Arrhenius relationship, the activation energies for the various relaxation processes and the translational motion of the water molecules were determined from temperature dependencies as a function of aggrecan concentration in the range 0–5.3% w/w. The longitudinal relaxation rate and inverse diffusion coefficient were approximately equally dependent on concentration and only increased by upto 20% from that of the salt solution. The transverse relaxation rate at high field demonstrated greatest concentration dependence, changing by an order of magnitude across the concentration range examined. We attribute this primarily to chemical exchange. Activation energies appeared to be approximately independent of aggrecan concentration, except for that of the low-field transverse relaxation rate, which decreased with concentration.

Sign in / Sign up

Export Citation Format

Share Document