Studies on Chloroplast Membranes. II. 13C Chemical Shifts and Longitudinal Relaxation Times of 1,2-Di[(9Z,12Z,15Z)-octadeca-9,12,15-trienoyl]-3-galactosyl-sn-glycerol and 1,2-Di[(9Z,12Z,15Z)-octadeca-9,12,15-trienoyl]-3-digalactosyl-sn-glycerol

1977 ◽  
Vol 30 (4) ◽  
pp. 823 ◽  
Author(s):  
S Johns ◽  
D Leslie ◽  
R Willing ◽  
D Bishop
Keyword(s):  
Relaxation Time ◽  
Chemical Shifts ◽  
Relaxation Times ◽  
Longitudinal Relaxation Time ◽  
Time Data ◽  
Longitudinal Relaxation ◽  
Monomeric Structure ◽  
13C Chemical Shift ◽  
Nuclear Overhauser ◽  
The Individual

The 13C chemical shift and longitudinal relaxation time (T1) of the individual carbon atoms in the two major lipids of chloroplast thylakoids, 1,2-di[(9Z,12Z,15Z)-octadeca-9,12,15-trienoyl]-3- galactosyl-sn-glycerol and 1,2-di[(9Z,12Z,15Z)-octadeca-9,12,15- trienoyl]-3-digalactosyl-sn-glycerol, have been measured in the three solvents: methanol[D4], chloroform[D] and water[D2]. The longitudinal relaxation time data are interpreted in terms of different secondary structures in the different solvents, a monomeric structure in methanol[D4], an inverted micellar structure in chloroform[D] and a bilayer structure in water[D2]. Two possible correlations times can be obtained from the longitudinal relaxation times of the galactosyl and glyceryl carbon atoms in chloroform[D] and water[D2] and nuclear Overhauser enhancement values have been used to assign the correlation times to these carbon atoms.

Studies on chloroplast membranes. III. 13C chemical shifts and longitudinal relaxation times of 1,2-Diacyl-3-(6-sulpho-α-quinovosyl)-sn-glycerol

1978 ◽  
Vol 31 (1) ◽  
pp. 65 ◽  
Author(s):  
SR Johns ◽  
DR Leslie ◽  
RI Willing ◽  
DG Bishop
Keyword(s):  
Chemical Shifts ◽  
Relaxation Times ◽  
Acid Group ◽  
Vesicular Structure ◽  
13C Chemical Shifts ◽  
Longitudinal Relaxation ◽  
Monomeric Structure ◽  
13C Chemical Shift ◽  
Nuclear Overhauser ◽  
The Individual

13C Chemical shifts, longitudinal relaxation times and some nuclear Overhauser enhancement factors of the individual carbon atoms in the chloroplast lipid, 1,2-diacyl-3-(6-sulpho-α-quinovosyl)-sn-glycerol (sl), have been measured in the three solvents: methanol[D4], chloroform[D] and water[D2]. Correlation times for the individual carbon atoms calculated from these results have been interpreted in terms of different secondary structures: a monomeric structure in methanol[D4], an inverted micellar structure in chloroform[D] and a bilayer vesicular structure in water[D2]. Substituent shift parameters have been determined for the sulphonic acid group from a series of alkanesulphonic acids and these have been used in the 13C chemical shift assignments in sl and a series of model compounds.

Studies on chloroplast membranes. IV. 13C chemical shifts and longitudinal relaxation times of 3-sn-phosphatidylglycerol

1981 ◽  
Vol 34 (2) ◽  
pp. 357 ◽  
Author(s):  
JM Coddington ◽  
SR Johns ◽  
DR Leslie ◽  
RI Willing ◽  
DG Bishop
Keyword(s):  
Chemical Shifts ◽  
Relaxation Times ◽  
Secondary Structures ◽  
Chloroplast Membranes ◽  
13C Chemical Shifts ◽  
Nuclear Overhauser Enhancement ◽  
Enhancement Factors ◽  
Longitudinal Relaxation ◽  
Monomeric Structure ◽  
Nuclear Overhauser

13C chemical shifts, longitudinal relaxation times and some nuclear Overhauser enhancement factors of individual carbon atoms in the chloroplast lipid, 3-sn-phosphatidylglycerol (pg), have been measured in (D4)methanol and (D)chloroform. Correlation times for individual carbon atoms calculated from these results have been interpreted in terms of different secondary structures: a monomeric structure in (D4)methanol and an inverted micelle in (D)chloroform. Differences in structures between the four major lipid components of the chloroplast membrane are briefly discussed.

Studies on Chloroplast Membranes. I. 13C Chemical Shifts and Longitudinal Relaxation Times of Carboxylic Acids

1977 ◽  
Vol 30 (4) ◽  
pp. 813 ◽  
Author(s):  
S Johns ◽  
D Leslie ◽  
R Willing ◽  
D Bishop
Keyword(s):  
Carboxylic Acid ◽  
Chemical Shift ◽  
Carboxylic Acids ◽  
Chemical Shifts ◽  
Relaxation Times ◽  
Segmental Motion ◽  
Unsaturated Carboxylic Acids ◽  
Longitudinal Relaxation ◽  
13C Chemical Shift ◽  
The Individual

The 13C chemical shift and longitudinal relaxation time (T1) of the individual carbon atoms in a series of carboxylic acids in CDCl3 solution have been determined. Substituent shift parameters have been derived from the chemical shift data. The relaxation times have been interpreted in terms of increasing segmental motion along the methylene chains of the carboxylic acid molecules which are associated at the carboxylic acid groups in the form of inverted micelles. Differences in the segmental motion between saturated and unsaturated carboxylic acids are rationalized on the grounds of intermolecular interactions between adjacent molecules in the inverted micelle structures.

Cross-linked polydimethylsiloxane colloid as novel contrast agent for gastrointestinal magnetic resonance imaging: Transient nuclear Overhauser effect within the interface

2020 ◽  
Vol 35 (2) ◽  
pp. 264-273
Author(s):  
Fu-Hu Su ◽  
Wang-Chuan Xiao ◽  
Sheann-Huei Lin ◽  
Qiyong Li
Keyword(s):  
Magnetic Resonance ◽  
Nuclear Overhauser Effect ◽  
Relaxation Times ◽  
Resonance Imaging ◽  
Transverse Relaxation ◽  
Overhauser Effect ◽  
Nuclear Magnetic Resonance Spectra ◽  
Relaxation Experiments ◽  
Longitudinal Relaxation ◽  
Nuclear Overhauser

With good contrast in T1 and T2 weighted imaging as well as low toxicity in 3- (4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay, this work proposes the cross-linked polydimethylsiloxane colloids as a novel non-ionic contrast agent for gastrointestinal magnetic resonance imaging. The experiments of nuclear magnetic resonance spectra and relaxation show that within the interface of the colloids, there are nuclear Overhauser effect and transient nuclear Overhauser effect (cross-relaxation). Regarding the longitudinal relaxation experiments of CH2CH2O segments of Tween 80, a two spins system is found and modeled well by the equation [Formula: see text] which is deduced based on the transient nuclear Overhauser effect proposed by Solomon. The arbitrary constant X is additionally added with the initial conditions ( Iz −  I0) t=0 = −2 XS0 and ( Sz −  S0) t=0 = −2 S0. For the two spins system, D1 and T1 are corresponding to longitudinal relaxation times of the bound water and the CH2CH2O respectively. Concerning the transverse relaxation experiments of the CH2CH2O, they agree with the equation with three exponential decays, defined by three relaxation times, likely corresponding to three mechanisms. These mechanisms possibly are intramolecular and intermolecular dipole–dipole (DD) interactions and scalar coupling. Within the interface, hydrogen bonding causes the positive nuclear Overhauser effect of the CH2CH2O’s nuclear magnetic resonance spectra, the transient nuclear Overhauser effect of the CH2CH2O’s longitudinal relaxation experiments and the intermolecular dipole–dipole interactions of the CH2CH2O’s transverse relaxation experiments.

scholarly journals FP243QUANTITATIVE LONGITUDINAL RELAXATION TIME (T1) AS PART OF MULTIPARAMETRIC MRI MAPPING REVEALS DISTINCT PATTERNS OF RENAL INJURY IN AKI AND CKD

2018 ◽  
Vol 33 (suppl_1) ◽  
pp. i112-i112
Author(s):  
Huda Mahmoud ◽  
Charlotte Buchanan ◽  
Eleanor Cox ◽  
Benjamin Prestwich ◽  
Maarten Taal ◽  
...  
Keyword(s):  
Relaxation Time ◽  
Renal Injury ◽  
Multiparametric Mri ◽  
Longitudinal Relaxation Time ◽  
Longitudinal Relaxation
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