2H NMR studies of dipalmitoylphosphatidylcholine and dipalmitoylphosphatidylcholine-cholesterol bilayers at high pressure

1998 ◽  
Vol 76 (11) ◽  
pp. 1512-1519 ◽  
Author(s):  
Boyan B Bonev ◽  
Michael R Morrow
Keyword(s):  
Nuclear Magnetic Resonance ◽  
High Pressure ◽  
Magnetic Resonance ◽  
Ambient Pressure ◽  
Phase Behaviour ◽  
Temperature Phase ◽  
Continuous Change ◽  
Nmr Studies ◽  
Resonance Model ◽  
Nuclear Magnetic

Wideline deuterium nuclear magnetic resonance was used to investigate the phase behaviour of bi layer dispersions of chain-perdeuterated dipalmitoylphosphatidylcholine (DPPC-d62) and DPPC-d62 containing 28.5 mol% cholesterol for temperatures between 0°C and 90°C and pressures from ambient to 270 MPa. Spectra were obtained over a range of temperature at ambient pressure, 100 MPa, and 210 MPa and over a range of pressure at fixed temperatures of 0°C and 45°C (40°C for the sample containing cholesterol). The combination of complementary isobaric and isothermal scans produced observations that suggest two possible refinements to previously reported DPPC-d62 pressure-temperature phase diagrams. In contrast to DPPC-d62, which displays at least three transitions as temperature is lowered from 90°C to 0°C at a fixed pressure of 210 MPa, the sample containing 28.5 mol% cholesterol displayed a continuous change from fluid to ordered over a wide temperature range for 210 MPa and below. These observations suggest that pressure does not induce any substantial repositioning of cholesterol in the bi layer over the range of conditions studied and that cholesterol reduces the sensitivity of bilayer properties to pressure.Key words: deuterium nuclear magnetic resonance, model membrane, high pressure, cholesterol, phase transition.

Nuclear magnetic resonance (NMR) studies of sintering effects on the lithium ion dynamics in Li1.5Al0.5Ti1.5(PO4)3

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Edda Winter ◽  
Philipp Seipel ◽  
Tatiana Zinkevich ◽  
Sylvio Indris ◽  
Bambar Davaasuren ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Lithium Ion ◽  
Magic Angle Spinning ◽  
Spin Lattice Relaxation ◽  
Magic Angle ◽  
Nmr Studies ◽  
Lithium Ions ◽  
Jump Dynamics ◽  
Nuclear Magnetic

Abstract Various nuclear magnetic resonance (NMR) methods are combined to study the structure and dynamics of Li1.5Al0.5Ti1.5(PO4)3 (LATP) samples, which were obtained from sintering at various temperatures between 650 and 900 °C. 6Li, 27Al, and 31P magic angle spinning (MAS) NMR spectra show that LATP crystallites are better defined for higher calcination temperatures. Analysis of 7Li spin-lattice relaxation and line-shape changes indicates the existence of two species of lithium ions with clearly distinguishable jump dynamics, which can be attributed to crystalline and amorphous sample regions, respectively. An increase of the sintering temperature leads to higher fractions of the fast lithium species with respect to the slow one, but hardly affects the jump dynamics in either of the phases. Specifically, the fast and slow lithium ions show jumps in the nanoseconds regime near 300 and 700 K, respectively. The activation energy of the hopping motion in the LATP crystallites amounts to ca. 0.26 eV. 7Li field-gradient diffusometry reveals that the long-range ion migration is limited by the sample regions featuring slow transport. The high spatial resolution available from the high static field gradients of our setup allows the observation of the lithium ion diffusion inside the small (<100 nm) LATP crystallites, yielding a high self-diffusion coefficient of D = 2 × 10−12 m2/s at room temperature.

scholarly journals A new high pressure sapphire nuclear magnetic resonance cell

1996 ◽  
Vol 67 (1) ◽  
pp. 240-243 ◽  
Author(s):  
Shi Bai ◽  
Craig M. Taylor ◽  
Charles L. Mayne ◽  
Ronald J. Pugmire ◽  
David M. Grant
Keyword(s):  
Nuclear Magnetic Resonance ◽  
High Pressure ◽  
Magnetic Resonance ◽  
Resonance Cell ◽  
Nuclear Magnetic

scholarly journals Magnetic flux tailoring through Lenz lenses for ultrasmall samples: A new pathway to high-pressure nuclear magnetic resonance

2017 ◽  
Vol 3 (12) ◽  
pp. eaao5242 ◽  
Author(s):  
Thomas Meier ◽  
Nan Wang ◽  
Dario Mager ◽  
Jan G. Korvink ◽  
Sylvain Petitgirard ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
High Pressure ◽  
Magnetic Resonance ◽  
Magnetic Flux ◽  
Nuclear Magnetic

Response of 31P-nuclear magnetic resonance spectra of frog skin to variations in PCO2 and hypoxia

1983 ◽  
Vol 245 (6) ◽  
pp. F792-F800
Author(s):  
R. L. Nunnally ◽  
J. S. Stoddard ◽  
S. I. Helman ◽  
J. P. Kokko
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Epithelial Transport ◽  
Transport Processes ◽  
Nmr Studies ◽  
Nernst Potential ◽  
31P Nuclear Magnetic Resonance ◽  
Order Of Magnitude ◽  
Epithelial Sheets ◽  
Nuclear Magnetic

31P-nuclear magnetic resonance (NMR) studies were conducted on split epithelial sheets of frog skins to examine the effects of hypoxia and respiratory pH variations on various phosphate-containing intracellular substrates. Frog skins were split into epithelial sheets from which the supporting tissue was removed. Epithelial sheets in either phosphate-free Cl--Ringer or phosphate-free SO2-4-Ringer were bubbled at room temperature with 100% N2, 100% O2, 2% CO2-98% O2, 5% CO2-95% O2, and 15% CO2-85% O2. The results show that the intracellular pH (pHi) with Cl- -Ringer was 7.19 and with SO2-4-Ringer was 7.42 with extracellular pH of 7.52 when bubbled with 100% O2. These pHiS indicate that H+ concentration is at least an order of magnitude less than predicted from the previously measured Nernst potential. With exposure to increasing extracellular PCO2, there is a polynomial decrease in pHi. The pHi tended to be more alkaline in SO2-4 -Ringer, suggesting the presence of a HCO-3/Cl- exchange mechanism. The ATP concentration is critically and reversibly dependent on PO2. ADP concentrations were consistently low in well-oxygenated conditions. Variable but small quantities of phosphocreatine were detected. These studies demonstrate further the potential importance in utilizing NMR spectroscopy to examine coupling of biochemical substrates to epithelial transport processes.

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