Fourier transform NMR: total automation of longitudinal relaxation time and nuclear Overhauser effect measurements

1976 ◽  
Vol 9 (11) ◽  
pp. 939-942 ◽  
Author(s):  
D Canet ◽  
B Diter ◽  
J P Marchal
Keyword(s):  
Fourier Transform ◽  
Relaxation Time ◽  
Nuclear Overhauser Effect ◽  
Longitudinal Relaxation Time ◽  
Overhauser Effect ◽  
Longitudinal Relaxation ◽  
Nuclear Overhauser

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.

123Te and 125Te Fourier Transform NMR Investigations

1977 ◽  
Vol 32 (11) ◽  
pp. 1263-1265 ◽  
Author(s):  
K. U. Buckler ◽  
J. Kronenbitter ◽  
. Lutz ◽  
A. Nollle
Keyword(s):  
Fourier Transform ◽  
Nuclear Overhauser Effect ◽  
Chemical Shifts ◽  
Magnetic Moments ◽  
Relaxation Times ◽  
Dipole Interaction ◽  
High Accuracy ◽  
Overhauser Effect ◽  
Nuclear Overhauser ◽  
Nmr Signals

Abstract The NMR signals of 123Te and 125Te have been observed in solutions of K2TeO3 and Na2TeO3 in D2O. In these solutions the ratios of Larmor frequencies ν(125Te)/ν(123Te), ν(125Te)/v(2H) and ν(125Te)/ν(23Na) have been determined with high accuracy. With the measured chemical shifts of 2H, 23Na, 125Te relative to infinitely diluted solutions the ratios of the Larmor frequencies are extrapolated and values of the magnetic moments are given. The relaxation times T1 and T2 are very different for 125Te in TeO32-: a ratio T1/T2 of 8.2 ± 0.4 has been found. No nuclear Overhauser effect due to dipole-dipole interaction of 125Te with the water protons has been detected.

scholarly journals Conformations of 3-Deazaadenosine, 3-Deaza-8-azaadenosine, and Benzimidazole-1-β-ᴅ-riboside in Solution: HRNMR-, Proton-Relaxation-Time-, and Nuclear-Overhauser- Effect Studies

1978 ◽  
Vol 33 (5-6) ◽  
pp. 305-316 ◽  
Author(s):  
H.-D. Lüdemann ◽  
H. Pladi ◽  
E. Westhof ◽  
L. B. Townsend
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Relaxation Time ◽  
Magnetic Resonance ◽  
Nuclear Overhauser Effect ◽  
Proton Relaxation ◽  
Proton Relaxation Time ◽  
Nuclear Overhauser Enhancement ◽  
Overhauser Effect ◽  
Nuclear Overhauser ◽  
Ribose Moiety

The solution conformations of 3-deazaadenosine, 3-deaza-8-azaadenosine, and benzimidazole-1-β- ᴅ-riboside have been determined by nuclear magnetic resonance methods in aqueous and ammonia solutions. The two-state S ⇄ N model of Altona and Sundaralingam is used to analyse the ribose moiety. In order to characterize the orientation of the base relative to the ribose, longitudinal proton relaxation time and nuclear Overhauser enhancement measurements have been carried out. It is shown that 3-deazaadenosine and benzimidazole-1-β-ᴅ-riboside exist preferentially in the S- syn-g+/t (70%) and the N-anti-g+/t (30%) conformation families. In the case of 3-deaza-8-aza- adenosine, some destabilization of the g+rotamer occurs. In this case, the pulsed methods seem to indicate a preference of the base for the anti range.

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.

1H NMR studies of [N-MeAib1, Tyr(Me)4]ANGII and [N-MeAib1, Tyr(Me)4, Ile8]ANGII in dimethylsulfoxide by nuclear Overhauser effect (NOE) enhancement spectroscopy: cis-trans Isomerism of the His-Pro bond

1990 ◽  
Vol 55 (4) ◽  
pp. 1106-1111 ◽  
Author(s):  
John Matsoukas ◽  
Paul Cordopatis ◽  
Raghav Yamdagni ◽  
Graham J. Moore
Keyword(s):  
1H Nmr ◽  
Nuclear Overhauser Effect ◽  
Nmr Studies ◽  
Restricted Rotation ◽  
Overhauser Effect ◽  
Major Isomer ◽  
Conformational Properties ◽  
Nuclear Overhauser

The conformational properties of the Sarmesin analogues [N-MeAib1, Tyr(Me)4]ANGII and [N-MeAib1, Tyr(Me)4, Ile8]ANGII in hexadeutero-dimethysulfoxide were investigated by Nuclear Overhauser Effect (NOE) Enhancement Studies. Cis-trans isomers (ratio 1 : 6) due to restricted rotation of the His-Pro bond were observed. Interresidue interactions between the His Cα proton and the two Pro Cδ protons revealed that the major isomer was the trans.

scholarly journals Cylindromicin from Arctic-Derived Fungus Tolypocladium sp. SCSIO 40433

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 1080
Author(s):  
Imran Khan ◽  
Jing Peng ◽  
Zhuangjie Fang ◽  
Wei Liu ◽  
Wenjun Zhang ◽  
...  
Keyword(s):  
Secondary Metabolites ◽  
Nuclear Overhauser Effect ◽  
Inhibition Activity ◽  
Tyrosinase Inhibition ◽  
Bioactive Natural Products ◽  
Chemical Structures ◽  
Overhauser Effect ◽  
Spectroscopic Analyses ◽  
Potential Resource ◽  
Nuclear Overhauser

The fungus strain SCSIO 40433 was isolated from an Arctic-derived glacier sediment sample and characterized as Tolypocladium cylindrosporum. A new compound, cylindromicin (1), and seven known secondary metabolites (2–8) were isolated from this strain. The chemical structures of these compounds were elucidated by comprehensive spectroscopic analyses. Cylindromicin (1) featured a 3,4-dihydro-2H-pyran skeleton. The absolute configuration of compound 1 was assigned via interpretation of key Nuclear Overhauser Effect Spectroscopy (NOESY) correlations and Electronic Circular Dichroism (ECD) calculation. Cylindromicin (1) exhibited significant tyrosinase inhibition activity. This study highlights Polar fungi as a potential resource for new bioactive natural products.

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