The effect of experimental parameters on the signal decay in double-PGSE experiments: Negative diffractions and enhancement of structural information

Shemesh, Noam; Cohen, Yoram

doi:10.1016/j.jmr.2008.09.006

Cited by 29 publications

(38 citation statements)

References 44 publications

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“…It is clear that for such experiments, the sequence with t m = 0 ms is inherently more robust towards size distributions. Previously, we have shown both theoretically 58,63 and experimentally 59,63 that the first zerocrossing is very sensitive to mixing times ͑as opposed to the second diffusion-diffraction trough͒, due to loss of correlation between the information encoded in the first and second diffusion periods. When monodisperse pores are present, this manifests in a shift in the location of the zero-crossing towards higher q-values, which gradually progresses into a complete loss of the zero-crossing.…”

Section: Discussionmentioning

confidence: 99%

“…The zero-crossings were recently experimentally observed for the first time, 59 and the effect of the experimental parameters on these negative diffractions was studied. The d-PFG sequence was first theoretically studied by Mitra in 1995 in the low-q regime and in limiting cases of the gradient durations, the diffusion periods, and mixing times.…”

Section: Diffractions͒mentioning

confidence: 89%

“…Moreover, diffusion in these microcapillaries has been extensively studied, and the response of the diffusion-diffraction patterns to variations in many experimental parameters has been shown for these microcapillaries in a number of studies. 28,[31][32][33]59,62,63,65 The main advantages for such a phantom is that the ground-truth is known a priori, such that a controlled increase in width of the mixture is possible; moreover, in these microcapillaries, completely restricted diffusion can be achieved, without exchange or permeability of the restricting compartment. We found that the theoretical predictions that were first published in Refs.…”

Section: Discussionmentioning

confidence: 99%

“…The results in all of the d-PFG experimental plots are presented as a function of 2q to be comparable with the s-PFG results. 59,65 To test the effect of the mixing time, the phantom with the largest standard deviation was used, namely, SD003. The experiments were performed with the same experimental parameters as above, except that for t m of 6, 25, and 50 ms, the sequence shown in Fig.…”

Section: Single-and Double-pgse Experiments On the Size Distributimentioning

confidence: 99%

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Detecting diffusion-diffraction patterns in size distribution phantoms using double-pulsed field gradient NMR: Theory and experiments

Shemesh

Özarslan

Basser

et al. 2010

The Journal of Chemical Physics

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NMR observable nuclei undergoing restricted diffusion within confining pores are important reporters for microstructural features of porous media including, inter-alia, biological tissues, emulsions and rocks. Diffusion NMR, and especially the single-pulsed field gradient ͑s-PFG͒ methodology, is one of the most important noninvasive tools for studying such opaque samples, enabling extraction of important microstructural information from diffusion-diffraction phenomena. However, when the pores are not monodisperse and are characterized by a size distribution, the diffusion-diffraction patterns disappear from the signal decay, and the relevant microstructural information is mostly lost. A recent theoretical study predicted that the diffusion-diffraction patterns in double-PFG ͑d-PFG͒ experiments have unique characteristics, such as zero-crossings, that make them more robust with respect to size distributions. In this study, we theoretically compared the signal decay arising from diffusion in isolated cylindrical pores characterized by lognormal size distributions in both s-PFG and d-PFG methodologies using a recently presented general framework for treating diffusion in NMR experiments. We showed the gradual loss of diffusion-diffraction patterns in broadening size distributions in s-PFG and the robustness of the zero-crossings in d-PFG even for very large standard deviations of the size distribution. We then performed s-PFG and d-PFG experiments on well-controlled size distribution phantoms in which the ground-truth is well-known a priori. We showed that the microstructural information, as manifested in the diffusion-diffraction patterns, is lost in the s-PFG experiments, whereas in d-PFG experiments the zero-crossings of the signal persist from which relevant microstructural information can be extracted. This study provides a proof of concept that d-PFG may be useful in obtaining important microstructural features in samples characterized by size distributions.

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Section: Discussionmentioning

confidence: 99%

Section: Diffractions͒mentioning

confidence: 89%

Section: Discussionmentioning

confidence: 99%

Section: Single-and Double-pgse Experiments On the Size Distributimentioning

confidence: 99%

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Detecting diffusion-diffraction patterns in size distribution phantoms using double-pulsed field gradient NMR: Theory and experiments

Shemesh

Özarslan

Basser

et al. 2010

The Journal of Chemical Physics

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“…[50,51] Ideally, information about diffusion processes in different spatial directions is obtained allowing therefore a threedimensional geometrical analysis. [52] The double echo technique, also in its bipolar variant, [53] is mainly used for pore or capillary characterisation. In the studies conducted by Ozarslan and colleagues [54,55] , spherical geometries like droplets are discussed.…”

Section: Pfg-nmr Approachesmentioning

confidence: 99%

NMR on emulsions: characterisation of liquid dispersed systems

Bernewitz¹,

Guthausen²,

Schuchmann³

2011

Magnetic Reson in Chemistry

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Pulsed field gradient NMR (PFG-NMR) is an important method for the characterisation of emulsions. Apart from its application in quality control and process development, especially high-field NMR methods can be applied to investigate emulsions properties on the molecular level. Meanwhile, complex emulsion structures such as double emulsions have been developed and require analytical tools especially for the determination of droplet size distributions. This contribution provides an overview on the possibilities and methods of PFG-NMR referring to measurement, data processing and interpretation of droplet size distributions. Comparison of techniques and measurements on double emulsions are presented.

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Transcatheter aortic valve implantation for treatment of patients with degenerated aortic bioprostheses—valve‐in‐valve technique

Gotzmann

Mügge

Bojara

2010

Cathet Cardio Intervent

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The effect of experimental parameters on the signal decay in double-PGSE experiments: Negative diffractions and enhancement of structural information

Cited by 29 publications

References 44 publications

Detecting diffusion-diffraction patterns in size distribution phantoms using double-pulsed field gradient NMR: Theory and experiments

Detecting diffusion-diffraction patterns in size distribution phantoms using double-pulsed field gradient NMR: Theory and experiments

NMR on emulsions: characterisation of liquid dispersed systems

Transcatheter aortic valve implantation for treatment of patients with degenerated aortic bioprostheses—valve‐in‐valve technique

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