Hydrophysiology NMR reveals mechanisms of steady-state water exchange in neural tissue DOI Creative Commons
Nathan H. Williamson,

Rea Ravin,

Teddy X. Cai

et al.

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2024, Volume and Issue: unknown

Published: Dec. 13, 2024

SUMMARY Water molecules exchange incessantly across cell membranes and among different environments within the cell, but it is not known what dominant transport pathways are whether they active or passive. We have developed realtime NMR hydrophysiology methods to study steady-state water diffusion in viable ex vivo neonatal mouse spinal cord samples. find that linked tonicity maintained by transport. Exchange slows following sodium–potassium pump inhibition recovers a normal rate after adding extracellular osmolytes. Additional information from apparent coefficients (ADC) differentiates inactive samples regardless of tonicity. Data modeling suggest multisite mechanism which modulates pathway between fast transmembrane slow intracellular exchange. The has high activation energy does require ions, suggesting this likely occurs through lipid bilayer rather than channels cotransporters. These may one day be translated clinical MRI scanners determine features cellular state . steady exchange, homeostasis, spectroscopy, DEXSY, tissue microstructure, porous media, membrane permeability, low-field single-sided NMR, coefficient, ADC, gray matter

Language: Английский

Diffusion power spectra as a window into dynamic materials architecture DOI Creative Commons
S Fricke,

Mia Salgado,

Shira Haber

et al.

Science Advances, Journal Year: 2025, Volume and Issue: 11(15)

Published: April 11, 2025

Chemical recycling of commodity and specialty polymers presents a multifaceted challenge for industrial societies. On one hand, macromolecular architectures must be engineered to yield durable products that, on the other rapidly deconstruct recyclable monomers under pre-determined conditions. Polymer deconstruction is chemical process that requires deep understanding molecular reactivity in heterogeneous media, where porous material evolve both space time. To build this understanding, we develop herein experimental analytical methods describing sets diffusive eigenmodes exist within time-varying, non-Euclidean boundary conditions, situation commonly encountered reactive chain fragments splay, alter their local dynamics, confinement reacting media. Diffusion power spectra, discerned experimentally by NMR, polymer solvent frequency-domain velocity autocorrelation functions are analyzed context physical models reactions parameterized with fractal mathematics. The results connect motion during acidolysis circular elastomers.

Language: Английский

Citations

0
Revisiting classical diffusion magnetic resonance methods as a means to measure time-dependent diffusion DOI Creative Commons
Teddy X. Cai, Nathan H. Williamson, Peter J. Basser

et al.

Magnetic Resonance Letters, Journal Year: 2025, Volume and Issue: unknown, P. 200197 - 200197

Published: April 1, 2025

Language: Английский

Citations

0
Measuring the velocity autocorrelation function using diffusion NMR DOI
Teddy X. Cai, Nathan H. Williamson,

Rea Ravin

et al.

The Journal of Chemical Physics, Journal Year: 2025, Volume and Issue: 162(17)

Published: May 2, 2025

Molecular self-diffusion in the presence of barriers results time-dependent displacements that are controlled by barrier characteristics, such as thickness, arrangement, and permeability, which manifests itself form ensemble-average velocity autocorrelation function (VAF). We describe a direct method to measure VAF based on combination diffusion-weighted nuclear magnetic resonance (NMR) measurements two time-shifted diffusion encodings separated longitudinal storage period. The estimated from simulated data is shown agree with known expression for impermeable parallel planes. Simulations periodically spaced, permeable planes connected, box-shaped pores also presented. find scaling faster than t−1/2 indicative permeation or exchange between domains this can be captured proposed method. As an experimental proof-of-concept, we present ex vivo neonatal mouse spinal cord studied using permanent magnet NMR MOUSE system. report transition t−3/2 at t ≈ 10 ms, consistent perhaps transmembrane water exchange. Compared other NMR-based approaches, potentially access several orders magnitude time (ms – s), revealing wealth behaviors one paradigm.

Language: Английский

Citations

0
Hydrophysiology NMR reveals mechanisms of steady-state water exchange in neural tissue DOI Creative Commons
Nathan H. Williamson,

Rea Ravin,

Teddy X. Cai

et al.

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2024, Volume and Issue: unknown

Published: Dec. 13, 2024

SUMMARY Water molecules exchange incessantly across cell membranes and among different environments within the cell, but it is not known what dominant transport pathways are whether they active or passive. We have developed realtime NMR hydrophysiology methods to study steady-state water diffusion in viable ex vivo neonatal mouse spinal cord samples. find that linked tonicity maintained by transport. Exchange slows following sodium–potassium pump inhibition recovers a normal rate after adding extracellular osmolytes. Additional information from apparent coefficients (ADC) differentiates inactive samples regardless of tonicity. Data modeling suggest multisite mechanism which modulates pathway between fast transmembrane slow intracellular exchange. The has high activation energy does require ions, suggesting this likely occurs through lipid bilayer rather than channels cotransporters. These may one day be translated clinical MRI scanners determine features cellular state . steady exchange, homeostasis, spectroscopy, DEXSY, tissue microstructure, porous media, membrane permeability, low-field single-sided NMR, coefficient, ADC, gray matter

Language: Английский

Citations

0