<figure><img src="image_46.png" /></figure>

<figure><img src="image_47.png" /><figcaption>Figure 45: a) Pulse sequence for the detection of hyperpolarized species in liquids. The symbols $t_{wait}$ and $t_r$ stand for the waiting delay and repetition time, respectively. b) Typical decay of the hyperpolarized quadruplet of [1-¹³C] sodium acetate recorded at 1.88 T (¹³C nuclear Larmor frequency = 20.13 MHz) and 298.15 K acquired using rf-pulses with a 5° angle without ¹H decoupling with a repetition time of 5 s and a waiting delay of 8 s. c) Decay of the signal integral (blue circles) fitted with Equation 29.</figcaption></figure>

What we have described here corresponds to the most basic liquid-state NMR experiments that can be performed in combination with dDNP, and already permits a number of applications such as monitoring of chemical reactions in the context of organic chemistry [214]–[217], enzymology [218], drug screening [110], [219]–[221], and other biological assays [222].

There are a number of more advanced rf-pulse sequences used in dDNP experiments. We will list some of them without going into the details. In particular, it is possible to 2D experiments or even 3D experiments. A straightforward approach consists of acquiring a series of spectra sequentially, exciting only a fraction of the magnetization for each spectrum [223]. This allowed for the acquisition of hyperpolarized HMQC and HSQC spectra with dDNP. More versatile is the use of ultrafast (UF)-2D NMR which is based on spatial encoding with pulsed field gradients [224]–[226]. UF-2D NMR allows for the acquisition of 2D spectra in a single scan and is compatible with dDNP hyperpolarization [224], [227] UF-2D NMR has successfully been used for HSQC, HMQC [227]–[229] and HMBC [137] experiments as well as for obtaining 2D diffusion-T₂ correlation maps (Laplace NMR) [230], [231] diffusion ordered spectroscopy (DOSY) or diffusion-chemical shift correlation shift maps [232], and COSY.[233] The band-Selective Optimized Flip-Angle Short-Transient heteronuclear multiple quantum coherence (SO-FAST-HMQC) methodology [234] has also been used together with dDNP to study protein

dynamics. [235]–[237]. In some particular molecular systems, hyperpolarization lifetimes (or coherences) can be extended by the use of long-lived states (and coherences) and used for specific application such as drug screening. [238]–[242] These applications are presented in a number of reviews on hyperpolarized NMR spectroscopy [21], [220], [226].

Finally, probably the main driving force for the development of dDNP has been its application to in vivo imaging [243]. Hyperpolarized metabolites such as [1-¹³C]pyruvate are used for the monitoring of real-time metabolism in three spatial dimensions [244], which allows for the detection of early-stage prostate tumours [245] in humans [30], [246], [247]. Other in vivo applications include the imaging of pH using ¹³C-bicarbonate [248] and angiography using hyperpolarized water [249]–[251].

## 8.2. Polarization quantification

Quantifying the polarization in the liquid-state is of major importance to assess the success of dDNP procedures. However, it can often be difficult and lengthy. In this section, two methods for the quantification of the polarization will be presented and compared. The first is conceptually the most straightforward and consists in comparing the integral between the hyperpolarized and thermal equilibrium signals. The second is named Spin Polarimetry (SPY) and consists of inferring the polarization of a nucleus of interest from the asymmetry of the multiplet pattern of a J-coupled neighbouring spin (the spy). We will also show how to analyse the polarization decay in the liquid-state and extract relaxation information while accounting for the effects of the rf-pulses, in some simple cases.

Note that we prefer to express dDNP results in terms of polarization rather than in terms of enhancement factors. This choice was made purposefully since enhancements depend on the field at which the liquid-state detection is performed. For example, injecting a sample with a ¹³C polarization of 20% represents enhancements of 24'700 and 12'300 at 9.4 T and 18.8 T, respectively. We thus consider that polarization gives a more objective metric in the context of dDNP.

**Comparison with a thermal equilibrium reference.** The polarization can be measured by comparing the signal integral of the hyperpolarized signal with that of a thermal equilibrium reference. The most direct comparison is the following: after recording the liquid-state hyperpolarized signal, the sample is allowed to remain in the spectrometer until the hyperpolarization has completely vanished, i.e., until thermal equilibrium is established. Then, a thermal equilibrium signal is recorded on the very sample produced by the dDNP experiment, with the same rf-probe on the same nucleus (only changing the number of scans, nutation angle and receiver gain, if appropriate). We will see how to calculate the polarization based on such measurement. In general, the polarization is given by:

$$P = P^{TE} \epsilon^{DNP} (19)$$

where $P^{TE}$ is the spin polarization at thermal equilibrium, calculated using the Boltzmann distribution, see Section 1. As an example, the ¹³C thermal polarization at 9.4 T and 298 K is 8.097x10⁻⁶. In general, the signal enhancement is given by the ratio between the hyperpolarized and thermal equilibrium signals, both normalized by the receiver gain, the number of scans and the pulse angle, $S_n^{DNP}$ and $S_n^{TE}$, respectively:
$$ \epsilon^{DNP} = \frac{S_n^{DNP}}{S_n^{TE}} (20) $$

where the normalized signal integral corresponds to that obtained with a single $\pi/2$ pulse and a receiver gain of 1. For a number of scans NS, a pulse angle $\theta$ and a receiver gain RG (assuming a linear scale), the normalized signal $S_n$ is:

$$ S_n = \frac{S}{RG \cdot NS \cdot \sin \theta} (21) $$

In particular, a common case is to record the hyperpolarized signals with small angle rf-pulses without averaging several scans while the thermal equilibrium is obtained by summing NS$^{TE}$ scans recorded with $\pi/2$ pulses. In this case, the signal enhancement yields:

$$ \epsilon^{DNP} = \frac{S^{DNP}}{S^{TE}} \frac{RG^{TE}}{RG^{DNP}} \frac{NS^{TE}}{\sin \theta^{DNP}} (22) $$

where the symbols and indices have the same meaning as above. However, it might not always be possible to record the thermal equilibrium signal, either because the sensitivity is too low or because the hyperpolarized solute has been consumed during the experiment (among other reasons). This situation may be encountered, for example, with $^{13}$C hyperpolarization and liquid-state detection at low magnetic fields. For example, in the case of [1-$^{13}$C] pyruvate, the three $^{1}$H methyl spins may be easily detected at low field in a single scan while the $^{13}$C signal would require the averaging of an outrageous number of scans after sample dissolution.

In this case, after the dDNP experiment, once the hyperpolarized signal has decayed, the $^{1}$H (or other nuclear spin) signal is recorded with sufficient SNR. In a separate experiment, a reference sample with a known concentration is measured. This allows for the determination of the normalized molar signal integral per equivalent solute spin, that is, the normalized signal integral for a solute concentration of 1 molL$^{-1}$ where the number of equivalent spins contributing to the integrated signal $n_{eq}$ has been accounted for:

$$ S_{n,m} = \frac{S}{RG \cdot NS \cdot C \cdot n_{eq}} (23) $$

where C is the concentration of the solute in the reference sample. This quantity can be measured for both $^{1}$H and $^{13}$C on the reference sample. The concentration of the solute in the dDNP sample is then determined comparing its $^{1}$H thermal signal integral with that of the reference sample:

$$ C^{DNP} = \frac{S_n^{TE} (^{1}H)}{S_{n,m}^{REF} (^{1}H)} \frac{1}{n_{eq} (^{1}H)} (24) $$

where $S_n^{TE}$ and $S_{n,m}^{REF}$ are normalized $^{1}$H signal integral of the dDNP sample and the normalized molar $^{1}$H signal integral per equivalent spin of reference sample, respectively, while $n_{eq}(^{1}H)$ is the number of equivalent $^{1}$H nuclei integrated for the thermal equilibrium signal ($n_{eq}(^{1}H) = 3$ in the case of pyruvate). The $^{13}$C thermal equilibrium signal integral of the dDNP sample $S_n^{TE}(^{13}C)$ which could not be measured directly can be calculated using the previously calculated concentration of the solute $C^{DNP}$ and normalized molar $^{13}$C signal integral per equivalent spin of reference sample $S_{n,m}^{REF}(^{13}C)$:

$$ S_n^{TE}(^{13}C) = S_{n,m}^{REF}(^{13}C) \cdot C^{DNP} \cdot n_{eq}(^{13}C) (25) $$

where $n_{eq}(^{13}C)$ is the number of equivalent $^{13}$C spins of the hyperpolarized signal. In the case of [1-$^{13}$C] pyruvate, there is a single $^{13}$C spin, so this number is 1. Finally, the calculated thermal equilibrium signal is used to estimate the signal enhancement and the polarization of the hyperpolarized spins by using Equations 19 and 20.

We previously mentioned the case where the hyperpolarized solute would be consumed during the course of the liquid-state experiment. The use of the method discussed above supposes that the signal of some nuclei of the solute can be recorded after the hyperpolarization has decayed. If the solute was consumed during the experiment, its concentration at the moment of injection needs to be estimated by other means. For example, provided the dissolution and injection process is sufficiently reproducible, a blank experiment without chemical reaction can be performed to measure the concentration of the solute in the liquid-state. If such an experiment is possible, the method above may be used to measure the polarization.

**Absolute polarization quantification by SPY-MR.** An alternative strategy allows for the absolute polarization quantification without relying on a thermal equilibrium reference measurement [45]. This method is only applicable for J-coupled spins and its application is straightforward only in the case where the hyperpolarized spin has a weakly coupled neighbour. Let us assume that we want to measure the polarization of a spin-$1/2$ labelled A which is weakly coupled to spins $X_n$. The coupling of A to X splits the NMR line of $X_n$ into a doublet. In conventional NMR, i.e., when the nuclear spin polarization is weak, the two peaks of the doublet of $X_n$ have equal intensities. Indeed, their relative intensity corresponds to the probability of finding A in state $\alpha$ or $\beta$; the two probabilities are practically equal when the polarization is low and so the two lines have equal intensities. However, when the polarization is far from zero, the excess of one nuclear state of A over the other causes the doublet of $X_n$ to become asymmetric. The polarization of A may therefore be read straightforwardly from the asymmetry of $X_n$ (for the case where the signs of the gyromagnetic ratios of the two spins are the same):

$$ P_A = \operatorname{sgn}(J_{AX}) \frac{S_{LF}^X - S_{HF}^X}{S_{LF}^X + S_{HF}^X} (26) $$

where $J_{AX}$, $S_{LF}^X$ and $S_{HF}^X$ are the J-coupling between A and $X_n$ and the signal intensities of the low and high frequency lines of the doublet, respectively. An interesting aspect of this method is that it allows for the determination of the sign of the J-coupling, provided one knows the sign of the spin polarization that the dDNP experiment has produced. The method may also be applicable to larger spin systems but the equations are not detailed here [45].

Equation 26 applies if the coupling between A and $X_n$ is weak, which is always true for heteronuclei at high field. This condition may still hold true in many homonuclear cases. The reader is referred to the original paper for the exact limits [45]. Furthermore, the asymmetry of $X_n$ reflects the Zeeman population of A only if higher spin orders are not populated. Certain relaxation pathways may be favoured during the transfer of the molecule from the polarizer to the liquid-state spectrometer, causing an excess/lack of an $2\hat{I}_{xz}\hat{I}_{yz}$ term. The presence of such terms in the density operator results in an
asymmetry which need not be a true reflection of the polarization before the transfer[177]. Note that a deviation from the high temperature approximation, i.e., from the linear approximation of Boltzmann's law, automatically leads to the appearance of a $2\hat{I}_{iz}\hat{I}_{z}$ term.

As compared with the use of a thermal equilibrium reference sample, polarization quantification by SPY-MR has the advantage of being faster since it does not require the detection of further signals in addition to the hyperpolarized one. Moreover, it is not subject to changes in the NMR sample that may occur between the acquisition of the hyperpolarized and thermal equilibrium spectra, such as chemical degradation, precipitation or appearance/disappearance of bubbles, to name a few. On the other hand, the SPY approach requires a good understanding of the spin dynamics at play during the transfer as one could falsely attribute a high polarization in the liquid-state to what could in fact be the presence of multiple spin order. Finally, we note that the two methods combined together can be used as a means to assess the nature of polarization losses during the transfer.

**Polarization decay and the effect of pulses.** The decay of hyperpolarization in the liquid-state is usually monitored using a series of small angle rf-pulses which allows for the determination of the $T_1$ relaxation time constant of the hyperpolarized solute. However, if the effect of the rf-pulses is not negligible, the fitted $T_1$ time constant may be underestimated. When the effect of the rf-pulses is negligible, the normalized mono-exponentially decaying signal as a function of time is:

$$ \frac{S(t)}{S_0} = \exp\left(-\frac{t}{T_1}\right) \quad (27) $$

Assuming a constant delay $\tau$ between the pulses with angle $\theta$, the corrected formula yields:

$$ \frac{S(t)}{S_0} = \exp\left(-\frac{t}{T_1}\right) \left(\cos \theta\right)^{\frac{t}{\tau}} \quad (28) $$

This equation can be rewritten as:

$$ \frac{S(t)}{S_0} = \exp\left\{-t\left(\frac{1}{T_1} - \frac{\ln|\cos \theta|}{\tau}\right)\right\} \quad (29) $$

Inspection of this formula shows that the effect of the rf-pulses preserves the mono-exponential character of the decay curve. As a consequence, if one does not pay attention to the effect of the rf-pulses, the $T_1$ constant may be underestimated. In the worst case, the decay is solely the consequences of the rf-pulses and not of relaxation. Figure 46 shows simulated decays that would be obtained using different rf-pulse angles. The figure shows how the apparent $T_1$ is affected by the rf-pulse angle.

<figure><img src="image_48.png" /><figcaption>Figure 46: Simulated hyperpolarized decay detected with pulses separated by 5 s with different rf-pulse angles for a nucleus with $T_1 = 60$ s. Dots represent the intensity of each measurement. Lines correspond to the</figcaption></figure>

decays obtained by Equation 29. The value $T_1^{app}$ is the apparent $T_1$ that would be obtained if the approximate Equation 27 were used.
## 9. Conclusions

We have presented a detailed review of dDNP experimentation, with the aim of providing useful guidelines and tips for readers in order to easily perform dDNP experiments in their own laboratories. We have discussed the following key areas: sample preparation and health; systems diagnosis and maintenance; mechanics and spin dynamics of sample dissolution; and the reliable quantification of nuclear spin polarization levels. For each subject we have highlighted problematic issues and provided simple solutions. These insights have been gained from our own practical experience in our own laboratory. Although methods and instrumentation will continue to evolve in the field, e.g., by the extended introduction of cryogen-free DNP polarizers and the implementation of dDNP at higher and higher magnetic fields, the basic conditions required in order to perform a successful dDNP experiment will remain largely the same, and as a result; we hope that, as the dDNP field broadens, this review will continue to provide assistance for those new to the field as well as longstanding members of the community, well into the future.

## 10. Acknowledgements

This research was supported by ENS-Lyon, the French CNRS, Lyon 1 University, the European Research Council under the European Union's Horizon 2020 research and innovation program (ERC Grant Agreements No. 714519 / HP4all and Marie Skłodowska-Curie Grant Agreement No. 766402 / ZULF). The authors gratefully acknowledge Bruker Biospin, and particularly Dmitry Eshchenko, Roberto Melzi, Marc Rossire, Marco Sacher and James Kempf for their technical advice and experimental support. The authors are indebted to Patrick Giraudeau, Dennis Kurzbach and Arnab Dey for kindly proof-reading the manuscript prior to submission, and Geoffrey Bodenhausen and Dominique Massiot for editing the manuscript and for all their corrections and constructive feedback. The authors additionally acknowledge Catherine Jose and Christophe Pages of the ISA Prototype Service; and Stéphane Martinez of the UCBL mechanical workshop for assistance with maintaining apparatus software and hardware.

## 11. References

[1] D. I. Hoult and R. E. Richards, "The signal-to-noise ratio of the nuclear magnetic resonance experiment," *J. Magn. Reson.*, vol. 24, no. 1, pp. 71–85, 1976, doi: 10.1016/0022-2364(76)90233-X.

[2] J. H. Ardenkjaer-Larsen, "On the present and future of dissolution-DNP," *J. Magn. Reson.*, vol. 264, pp. 3–12, Mar. 2016, doi: 10.1016/j.jmr.2016.01.015.

[3] M. L. Hirsch, B. A. Smith, M. Mattingly, A. G. Goloshevsky, M. Rosay, and J. G. Kempf, "Transport and imaging of brute-force 13C hyperpolarization," *J. Magn. Reson.*, vol. 261, pp. 87–94, 2015, doi: 10.1016/j.jmr.2015.09.017.

[4] M. L. Hirsch, N. Kalechofsky, A. Belzer, M. Rosay, and J. G. Kempf, "Brute-Force Hyperpolarization for NMR and MRI," *J. Am. Chem. Soc.*, vol. 137, no. 26, pp. 8428–8434, Jul. 2015, doi: 10.1021/jacs.5b01252.

[5] D. G. Gadian, K. S. Panesar, A. J. Perez Linde, A. J. Horsewill, W. Köckenberger, and J. R. Owers-Bradley, "Preparation of highly polarized nuclear spin

systems using brute-force and low-field thermal mixing," *Phys. Chem. Chem. Phys.*, vol. 14, no. 16, pp. 5397–5402, Mar. 2012, doi: 10.1039/c2cp23536f.

[6] D. T. Peat, M. L. Hirsch, D. G. Gadian, A. J. Horsewill, J. R. Owers-Bradley, and J. G. Kempf, "Low-field thermal mixing in [1-13C] pyruvic acid for brute-force hyperpolarization," *Phys. Chem. Chem. Phys.*, vol. 18, no. 28, pp. 19173–19182, 2016, doi: 10.1039/c6cp02853e.

[7] A. Abragam and M. Goldman, "Principles of dynamic nuclear polarisation," *Reports Prog. Phys.*, vol. 41, no. 3, pp. 395–467, 1978, doi: 10.1088/0034-4885/41/3/002.

[8] A. S. Lilly Thankamony, J. J. Wittmann, M. Kaushik, and B. Corzilius, "Dynamic nuclear polarization for sensitivity enhancement in modern solid-state NMR," *Prog. Nucl. Magn. Reson. Spectrosc.*, vol. 102–103, pp. 120–195, Nov. 2017, doi: 10.1016/j.pnmrs.2017.06.002.

[9] J. H. Ardenkjaer-Larsen, B. Fridlund, A. Gram, G. Hansson, L. Hansson, M. H. Lerche, R. Servin, M. Thaning, and K. Golman, "Increase in signal-to-noise ratio of >10,000 times in liquid-state NMR," *Proc. Natl. Acad. Sci. U. S. A.*, vol. 100, no. 18, pp. 10158–10163, Sep. 2003, doi: 10.1073/pnas.1733835100.

[10] J. H. Ardenkjaer-Larsen, "Hyperpolarized MR – What's up Doc?," *J. Magn. Reson.*, vol. 306, pp. 124–127, 2019, doi: 10.1016/j.jmr.2019.07.017.

[11] J. H. Ardenkjaer-Larsen, "Introduction to dissolution DNP: Overview, instrumentation, and human applications," *eMagRes*, vol. 7, no. 4, pp. 63–78, 2018, doi: 10.1002/9780470034590.emrstm1549.

[12] W. T. Wenckebach, "Dynamic nuclear polarization via the cross effect and thermal mixing: A. The role of triple spin flips," *J. Magn. Reson.*, vol. 299, pp. 124–134, 2019, doi: 10.1016/j.jmr.2018.12.018.

[13] W. T. Wenckebach, "Dynamic nuclear polarization via the cross effect and thermal mixing: B. Energy transport," *J. Magn. Reson.*, vol. 299, pp. 151–167, Feb. 2019, doi: 10.1016/j.jmr.2018.12.020.

[14] S. Jannin, A. Comment, and J. J. van der Klink, "Dynamic Nuclear Polarization by Thermal Mixing Under Partial Saturation," *Appl. Magn. Reson.*, vol. 43, no. 1–2, pp. 59–68, 2012, doi: 10.1007/s00723-012-0363-4.

[15] D. Shimon, Y. Hovav, I. Kaminker, A. Feintuch, D. Goldfarb, and S. Vega, "Simultaneous DNP enhancements of 1H and 13C nuclei: Theory and experiments," *Phys. Chem. Chem. Phys.*, vol. 17, no. 17, pp. 11868–11883, 2015, doi: 10.1039/c5cp00406c.

[16] Y. Hovav, A. Feintuch, and S. Vega, "Theoretical aspects of dynamic nuclear polarization in the solid state - The cross effect," *J. Magn. Reson.*, vol. 214, pp. 29–41, 2012, doi: 10.1016/j.jmr.2011.09.047.

[17] W. T. Wenckebach, "Spectral diffusion and dynamic nuclear polarization: Beyond the high temperature approximation," *J. Magn. Reson.*, vol. 284, pp. 104–114, 2017, doi: 10.1016/j.jmr.2017.10.001.

[18] V. A. Atsarkin, "Dynamic nuclear polarization: Yesterday, today, and tomorrow," *J. Phys. Conf. Ser.*, vol. 324, p. 012003, 2011, doi: 10.1088/1742-6596/324/1/012003.

[19] K. V. Kovtunov, E. V. Pokochueva, O. G. Salnikov, S. F. Cousin, D. Kurzbach, B. Vuichoud, S. Jannin, E. Y.
Chekmenev, B. M. Goodson, D. A. Barskiy, and I. V. Koptyug, "Hyperpolarized NMR Spectroscopy: *d* - DNP, PHIP, and SABRE Techniques," *Chem. - An Asian J.*, vol. 13, no. 15, pp. 1857–1871, Aug. 2018, doi: 10.1002/asia.201800551.

[20] K. M. Brindle, S. E. Bohndiek, F. A. Gallagher, and M. I. Kettunen, "Tumor imaging using hyperpolarized 13C magnetic resonance spectroscopy," *Magn. Reson. Med.*, vol. 66, no. 2, pp. 505–519, 2011, doi: 10.1002/mrm.22999.

[21] B. Plainchont, P. Berruyer, J.-N. N. Dumez, S. Jannin, and P. Giraudeau, "Dynamic Nuclear Polarization Opens New Perspectives for NMR Spectroscopy in Analytical Chemistry," *Anal. Chem.*, vol. 90, no. 6, pp. 3639–3650, Mar. 2018, doi: 10.1021/acs.analchem.7b05236.

[22] S. Jannin, J.-N. N. Dumez, P. Giraudeau, and D. Kurzbach, "Perspectives in Magnetic Resonance Application and methodology of dissolution dynamic nuclear polarization in physical, chemical and biological contexts," *J. Magn. Reson.*, vol. 305, pp. 41–50, 2019, doi: 10.1016/j.jmr.2019.06.001.

[23] A. A. Bornet, A. Pinon, A. Jhajharia, M. Baudin, X. Ji, L. Emsley, G. Bodenhausen, J. H. Ardenkjaer-Larsen, and S. Jannin, "Microwave-gated dynamic nuclear polarization," *Phys. Chem. Chem. Phys.*, vol. 18, no. 44, pp. 30530–30535, 2016, doi: 10.1039/c6cp05587g.

[24] W. Kockenberger, "Dissolution dynamic nuclear polarization," in *eMagRes*, vol. 3, no. 2, Chichester, UK: John Wiley & Sons, Ltd, 2014, pp. 161–170.

[25] Ü. Akbey, W. Trent Franks, A. Linden, M. Orwick-Rydmark, S. Lange, and H. Oschkinat, *Dynamic nuclear polarization enhanced NMR in the solid-state*, vol. 338, 2013.

[26] F. Jähnig, G. Kwiatkowski, and M. Ernst, "Conceptual and instrumental progress in dissolution DNP," *J. Magn. Reson.*, vol. 264, no. Supplement C, pp. 22–29, 2016, doi: 10.1016/j.jmr.2015.12.024.

[27] J. Van Bentum, B. Van Meerten, M. Sharma, and A. Kentgens, "Perspectives on DNP-enhanced NMR spectroscopy in solutions," *J. Magn. Reson.*, vol. 264, pp. 59–67, 2016, doi: 10.1016/j.jmr.2016.01.010.

[28] K. R. Keshari and D. M. Wilson, "Chemistry and biochemistry of 13C hyperpolarized magnetic resonance using dynamic nuclear polarization," *Chem. Soc. Rev.*, vol. 43, no. 5, pp. 1627–1659, 2014, doi: 10.1039/c3cs60124b.

[29] P. Berthault, C. Boutin, C. Martineau-corcos, and G. Carret, "Progress in Nuclear Magnetic Resonance Spectroscopy Use of dissolved hyperpolarized species in NMR: Practical considerations," *Prog. Nucl. Magn. Reson. Spectrosc.*, vol. 118–119, pp. 74–90, 2020, doi: 10.1016/j.pnmrs.2020.03.002.

[30] S. E. Day, M. I. Kettunen, F. A. Gallagher, D. E. Hu, M. Lerche, J. Wolber, K. Golman, J. H. Ardenkjaer-Larsen, and K. M. Brindle, "Detecting tumor response to treatment using hyperpolarized 13C magnetic resonance imaging and spectroscopy," *Nat. Med.*, vol. 13, no. 11, pp. 1382–1387, 2007, doi: 10.1038/nm1650.

[31] P. Miéville, S. Jannin, L. Helm, and G. Bodenhausen, "Kinetics of yttrium-Ligand complexation monitored using hyperpolarized 89Y as a model for gadolinium in contrast agents," *J. Am. Chem. Soc.*, vol. 132, no.

14, pp. 5006–5007, 2010, doi: 10.1021/ja1013954.

[32] A. Bornet and S. Jannin, "Optimizing dissolution dynamic nuclear polarization," *J. Magn. Reson.*, vol. 264, pp. 13–21, 2016, doi: 10.1016/j.jmr.2015.12.007.

[33] J. Leggett, R. Hunter, J. Granwehr, R. Panek, A. J. Perez-Linde, A. J. Horsewill, J. McMaster, G. Smith, and W. Köckenberger, "A dedicated spectrometer for dissolution DNP NMR spectroscopy," *Phys. Chem. Chem. Phys.*, vol. 12, no. 22, p. 5883, 2010, doi: 10.1039/c002566f.

[34] K. Kouřil, H. Kouřilová, S. Bartram, M. H. Levitt, and B. Meier, "Scalable dissolution-dynamic nuclear polarization with rapid transfer of a polarized solid," *Dec. 2019*. doi: 10.1038/s41467-019-09726-5.

[35] A. Leavesley, C. B. Wilson, M. Sherwin, and S. Han, "Effect of water/glycerol polymorphism on dynamic nuclear polarization," *Phys. Chem. Chem. Phys.*, vol. 20, no. 15, pp. 9897–9903, 2018, doi: 10.1039/c8cp00358k.

[36] L. Lumata, Z. Kovacs, A. D. Sherry, C. Malloy, S. Hill, J. Van Tol, L. Yu, L. Song, and M. E. Merritt, "Electron spin resonance studies of trityl OX063 at a concentration optimal for DNP," *Phys. Chem. Chem. Phys.*, vol. 15, no. 24, pp. 9800–9807, 2013, doi: 10.1039/c3cp50186h.

[37] L. L. Lumata, R. Martin, A. K. Jindal, Z. Kovacs, M. S. Conradi, and M. E. Merritt, "Development and performance of a 129-GHz dynamic nuclear polarizer in an ultra-wide bore superconducting magnet," *Magn. Reson. Mater. Physics, Biol. Med.*, vol. 28, no. 2, pp. 195–205, 2015, doi: 10.1007/s10334-014-0455-2.

[38] Y. Crémillieux, F. Goutailler, B. Montcel, D. Grand, G. Vermeulen, and P. E. Wolf, "A Super-Wide Bore DNP System for Multiple Sample Polarization: Cryogenic Performance and Polarization at Low Temperature," *Appl. Magn. Reson.*, vol. 43, no. 1–2, pp. 167–180, 2012, doi: 10.1007/s00723-012-0354-5.

[39] M. Batel, M. Krajewski, K. Weiss, O. With, A. Däpp, A. Hunkeler, M. Gimersky, K. P. Pruessmann, P. Boesiger, B. H. Meier, S. Kozerke, and M. Ernst, "A multi-sample 94 GHz dissolution dynamic-nuclear-polarization system," *J. Magn. Reson.*, vol. 214, no. 1, pp. 166–174, 2012, doi: 10.1016/j.jmr.2011.11.002.

[40] A. Bornet, J. Milani, B. Vuichoud, A. J. Perez Linde, G. Bodenhausen, and S. Jannin, "Microwave frequency modulation to enhance Dissolution Dynamic Nuclear Polarization Dedicated to To Martial Rey, as a token of appreciation," *Chem. Phys. Lett.*, vol. 602, pp. 63–67, 2014, doi: 10.1016/j.cplett.2014.04.013.

[41] B. Vuichoud, A. Bornet, F. de Nanteuil, J. Milani, E. Canet, X. Ji, P. Miéville, E. Weber, D. Kurzbach, A. Flamm, R. Konrat, A. D. Gossert, S. Jannin, and G. Bodenhausen, "Filterable Agents for Hyperpolarization of Water, Metabolites, and Proteins," *Chem. - A Eur. J.*, vol. 22, no. 41, pp. 14696–14700, Oct. 2016, doi: 10.1002/chem.201602506.

[42] M. Cavaillès, A. A. Bornet, X. Jaurand, B. Vuichoud, D. Baudouin, M. Baudin, L. Veyre, G. Bodenhausen, J.-N. Dumez, S. Jannin, C. Copéret, and C. Thiculeux, "Tailored Microstructured Hyperpolarizing Matrices for Optimal Magnetic Resonance Imaging," *Angew. Chemie - Int. Ed.*, vol. 57, no. 25, pp. 7453–7457, Jun.
2018, doi: 10.1002/anie.201801009.

[43] B. C. Dollmann, M. J. N. Junk, M. Drechsler, H. W. Spiess, D. Hinderberger, and K. Münnemann, "Thermoresponsive, spin-labeled hydrogels as separable DNP polarizing agents," *Phys. Chem. Chem. Phys.*, vol. 12, no. 22, p. 5850, 2010, doi: 10.1039/c003349a.

[44] D. Gajan, A. Bornet, B. Vuichoud, J. Milani, R. Melzi, H. A. Van Kalkeren, L. Veyre, C. Thieuleux, M. P. Conley, W. R. Grüning, M. Schwarzwälder, A. Lesage, C. Copéret, G. Bodenhausen, L. Emsley, and S. Jannin, "Hybrid polarizing solids for pure hyperpolarized liquids through dissolution dynamic nuclear polarization," *Proc. Natl. Acad. Sci.*, vol. 111, no. 41, pp. 14693-14697, Oct. 2014, doi: 10.1073/pnas.1407730111.

[45] B. Vuichoud, J. Milani, Q. Chappuis, A. Bornet, G. Bodenhausen, and S. Jannin, "Measuring absolute spin polarization in dissolution-DNP by Spin Polarimetry Magnetic Resonance (SPY-MR) Dedicated to Stefan Schäublin, Alfred Höhener and Richard Ernst for their pioneering work," *J. Magn. Reson.*, vol. 260, pp. 127-135, 2015, doi: 10.1016/j.jmr.2015.09.006.

[46] Y. Li, A. Equbal, K. Tagami, S. Han, and H. Songi, "Electron spin density matching for cross-effect dynamic nuclear polarization ChemComm Chemical Communications," *Chem. Commun.*, vol. 55, no. 53, pp. 7571-7716, 2019, doi: 10.1039/c9cc03499d.

[47] J. Granwehr, J. Leggett, and W. Köckenberger, "A low-cost implementation of EPR detection in a dissolution DNP setup," *J. Magn. Reson.*, vol. 187, no. 2, pp. 266-276, 2007, doi: 10.1016/j.jmr.2007.05.011.

[48] M. M. Albannay, J. M. O. Vinther, A. Capozzi, V. Zhurbenko, and J. H. Ardenkjaer-Larsen, "Optimized microwave delivery in dDNP," *J. Magn. Reson.*, vol. 305, pp. 58-65, 2019, doi: 10.1016/j.jmr.2019.06.004.

[49] P. Miéville, S. Jannin, and G. Bodenhausen, "Relaxometry of insensitive nuclei: Optimizing dissolution dynamic nuclear polarization," *J. Magn. Reson.*, vol. 210, no. 1, pp. 137-140, 2011, doi: 10.1016/j.jmr.2011.02.006.

[50] J. Milani, B. Vuichoud, A. Bornet, P. Miéville, R. Mottier, S. Jannin, and G. Bodenhausen, "A magnetic tunnel to shelter hyperpolarized fluids," *Rev. Sci. Instrum.*, vol. 86, no. 2, 2015, doi: 10.1063/1.4908196.

[51] P. Miéville, P. Ahuja, R. Sarkar, S. Jannin, P. R. P. R. P. R. Vasos, S. Gerber-Lemaire, M. Mishkovsky, A. Comment, R. Gruetter, O. Ouari, P. Tordo, and G. Bodenhausen, "Scavenging free radicals to preserve enhancement and extend relaxation times in NMR using dynamic nuclear polarization," *Angew. Chemie - Int. Ed.*, vol. 49, no. 35, p. 7834, 2010, doi: 10.1002/anie.201000934.

[52] A. Bornet, R. Melzi, A. J. Perez Linde, P. Hautle, B. Van Den Brandt, S. Jannin, and G. Bodenhausen, "Boosting dissolution dynamic nuclear polarization by cross polarization," *J. Phys. Chem. Lett.*, vol. 4, no. 1, pp. 111-114, 2013, doi: 10.1021/jz301781t.

[53] S. R. Hartmann and E. L. Hahn, "Nuclear double resonance in the rotating frame," *Phys. Rev.*, vol. 128, no. 5, pp. 2042-2053, 1962, doi: 10.1103/PhysRev.128.2042.

[54] A. Pines, M. G. Gibby, and J. S. Waugh, "Proton-enhanced nuclear induction spectroscopy 13C

chemical shielding anisotropy in some organic solids," *Chem. Phys. Lett.*, vol. 15, no. 3, pp. 373-376, 1972, doi: 10.1016/0009-2614(72)80191-X.

[55] S. Jannin, A. A. Bornet, S. Colombo, and G. Bodenhausen, "Low-temperature cross polarization in view of enhancing dissolution Dynamic Nuclear Polarization in NMR," *Chem. Phys. Lett.*, vol. 517, no. 4-6, pp. 234-236, 2011, doi: 10.1016/j.cplett.2011.10.042.

[56] A. Bornet, R. Melzi, S. Jannin, and G. Bodenhausen, "Cross Polarization for Dissolution Dynamic Nuclear Polarization Experiments at Readily Accessible Temperatures 1.2 < T < 4.2 K," *Appl. Magn. Reson.*, vol. 43, no. 1-2, pp. 107-117, 2012, doi: 10.1007/s00723-012-0358-1.

[57] J. Milani, B. Vuichoud, A. Bornet, R. Melzi, S. Jannin, and G. Bodenhausen, "Hyperpolarization of nitrogen-15 nuclei by cross polarization and dissolution dynamic nuclear polarization," *Rev. Sci. Instrum.*, vol. 88, no. 1, 2017, doi: 10.1063/1.4973777.

[58] M. Otikovs, G. L. Olsen, Ē. Kupče, and L. Frydman, "Natural Abundance, Single-Scan 13C-13C-Based Structural Elucidations by Dissolution DNP NMR," *J. Am. Chem. Soc.*, vol. 141, no. 5, pp. 1857-1861, 2019, doi: 10.1021/jacs.8b12216.

[59] M. Baudin, B. Vuichoud, A. Bornet, G. Bodenhausen, and S. Jannin, "A cryogen-consumption-free system for dynamic nuclear polarization at 9.4 T," *J. Magn. Reson.*, vol. 294, pp. 115-121, Sep. 2018, doi: 10.1016/j.jmr.2018.07.001.

[60] B. Vuichoud, "Novel Sample Formulations for Pure and Persistent Hyperpolarized Solutions via Dissolution Dynamic Nuclear Polarization," 2017.

[61] K. Murata and H. Tanaka, "in aqueous organic solutions," *Nat. Commun.*, pp. 4-6, 2013, doi: 10.1038/ncomms3844.

[62] K. Murata, "Liquid-liquid transition without macroscopic phase separation in a water-glycerol mixture," *Nat. Mater.*, vol. 11, no. March, pp. 4-6, 2012, doi: 10.1038/nmat3271.

[63] I. Popov, A. G. Gutina, A. P. Sokolov, and Y. Feldman, "water-glycerol mixtures," pp. 18063-18071, 2015, doi: 10.1039/c5cp02851e.

[64] D. A. Jahn, J. Wong, J. Bachler, and N. Giovambattista, "Glass polymorphism in glycerol-water mixtures: I. A computer simulation study," no. Ldl, pp. 11042-11057, 2016, doi: 10.1039/c6cp00075d.

[65] P. Cerreia Vioglio, G. Mollica, M. Juramy, C. E. Hughes, P. A. Williams, F. Ziarelli, S. Viel, P. Thureau, and K. D. M. M. Harris, "Insights into the Crystallization and Structural Evolution of Glycine Dihydrate by In Situ Solid-State NMR Spectroscopy," *Angew. Chemie - Int. Ed.*, vol. 57, no. 22, pp. 6619-6623, May 2018, doi: 10.1002/anie.201801114.

[66] V. Berejnov, N. S. Husseini, A. Alsaied, and R. E. Thorne, "research papers Effects of cryoprotectant concentration and cooling rate on vitrification of aqueous solutions research papers," pp. 244-251, 2006, doi: 10.1107/S0021889806004717.

[67] N. Giovambattista and T. Loerting, "Glass polymorphism in glycerol&\#x2013;water mixtures: II. Experimental studies," pp. 11058-11068, 2016, doi: 10.1039/c5cp08069j.
[68] P. G. Debenedetti and H. E. Stanley, "[Debenedetti and Stanley, 2003] Supercooled and glassy water.pdf," *Physics Today*, vol. June. pp. 40–46, 2003.

[69] K. Yoshizawa, A. Toyotama, T. Okuzono, and J. Yamanaka, "Exclusion of impurity particles in charged colloidal crystals," *Soft Matter*, vol. 10, no. 19, pp. 3357–3361, 2014, doi: 10.1039/c5sm52912f.

[70] B. Wunderlich, "Theory of cold crystallization of high polymers," *J. Chem. Phys.*, vol. 29, no. 6, pp. 1395–1404, 1958, doi: 10.1063/1.1744729.

[71] E. M. M. Weber, G. Sicoli, H. Vezin, G. Frébourg, D. Abergel, G. Bodenhausen, and D. Kurzbach, "Sample Ripening through Nanophase Separation Influences the Performance of Dynamic Nuclear Polarization," *Angew. Chemie - Int. Ed.*, vol. 57, no. 18, pp. 5171–5175, 2018, doi: 10.1002/anie.201800493.

[72] D. Bruck, R. Dudley, C. A. Fyfe, and J. Van Delden, "Sample magnetization using immobilized free radicals for use in flow NMR systems," *J. Magn. Reson.*, vol. 42, no. 1, pp. 51–59, 1981, doi: 10.1016/0022-2364(81)90009-3.

[73] R. Gitti, C. Wild, C. Tsiao, K. Zimmer, T. E. Glass, and H. C. Dorn, "Solid-Liquid Intermolecular Transfer of Dynamic Nuclear Polarization. Enhanced Flowing Fluid JH NMR Signals via Immobilized Spin Labels," *J. Am. Chem. Soc.*, vol. 110, no. 7, pp. 2294–2296, 1988, doi: 10.1021/ja00215a047.

[74] D. L. Silverio, H. A. Van Kalkeren, T.-C. C. Ong, M. Baudin, M. Yulikov, L. Veyre, P. Berruyer, S. Chaudhari, D. Gajan, D. Baudouin, M. Cavaillès, B. Vuichoud, A. elien Bornet, G. Jeschke, G. Bodenhausen, A. Lesage, L. Emsley, S. Jannin, C. Thieuleux, C. Cop eret, M. Cavaillès, B. Vuichoud, A. Bornet, G. Jeschke, G. Bodenhausen, A. Lesage, L. Emsley, S. Jannin, C. Thieuleux, and C. Copéret, "Tailored Polarizing Hybrid Solids with Nitroxide Radicals Localized in Mesostructured Silica Walls," *Helv. Chim. Acta*, vol. 100, no. 6, 2017, doi: 10.1002/hlca.201700101.

[75] E. Besson, F. Ziarelli, E. Bloch, G. Gerbaud, S. Queyroy, S. Viel, and S. Gastaldi, "Silica materials with wall-embedded nitroxides provide efficient polarization matrices for dynamic nuclear polarization NMR," *Chem. Commun.*, vol. 52, no. 32, pp. 5531–5533, Apr. 2016, doi: 10.1039/c6cc01809b.

[76] T. Cheng, M. Mishkovsky, M. J. N. Junk, K. Münnemann, and A. Comment, "Producing Radical-Free Hyperpolarized Perfusion Agents for In Vivo Magnetic Resonance Using Spin-Labeled Thermoresponsive Hydrogel," *Macromol. Rapid Commun.*, vol. 37, no. 13, pp. 1074–1078, 2016, doi: 10.1002/marc.201600133.

[77] T. El Darai, S. F. Cousin, Q. Chappuis, M. Ceillier, J. G. Kempf, D. Eshchenko, R. Melzi, M. Schnell, L. Gremillard, A. Bornet, J. Milani, Basile Buichou, O. Cala, D. Montarnal, and S. Jannin, "Porous Functionalized Polymers enable Generating and Transporting Hyperpolarized Arbitrary Solutions," *Nat. Res.*, pp. 1–20, 2021, doi: 10.21203/rs.3.rs-123790/v1.

[78] A. Cavagna, "Supercooled liquids for pedestrians," *Phys. Rep.*, vol. 476, no. 4–6, pp. 51–124, 2009, doi: 10.1016/j.physrep.2009.03.003.

[79] B. Lama, J. H. P. Collins, D. Downes, A. N. Smith,

and J. R. Long, "Expeditious dissolution dynamic nuclear polarization without glassing agents," *NMR Biomed.*, vol. 29, no. 3, pp. 226–231, 2016, doi: 10.1002/nbm.3473.

[80] B. Y. J. L. Stephenson, "ICE CRYSTAL GROWTH DURING THE RAPID FREEZING OF TISSUES," vol. 2, no. 4, pp. 45–52, 1956.

[81] C. Kroll and H. H. Borchert, "Metabolism of the stable nitroxyl radical 4-oxo-2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPONE)," *Eur. J. Pharm. Sci.*, vol. 8, no. 1, pp. 5–9, 1999, doi: 10.1016/S0928-0987(98)00047-5.

[82] C. L. Hawkins and M. J. Davies, "Detection and characterisation of radicals in biological materials using EPR methodology," *Biochim. Biophys. Acta - Gen. Subj.*, vol. 1840, no. 2, pp. 708–721, 2014, doi: 10.1016/j.bbagen.2013.03.034.

[83] J. B. Gerken and S. S. Stahl, "High-potential electrocatalytic O2 reduction with nitroxyl/NOx mediators: Implications for fuel cells and aerobic oxidation catalysis," *ACS Cent. Sci.*, vol. 1, no. 5, pp. 234–243, 2015, doi: 10.1021/acscentsci.5b00163.

[84] G. R. Eaton, S. S. Eaton, D. P. Barr, and R. T. Weber, *Quantitative EPR*, SpringerWi. Springer New York, 2010.

[85] A. Comment, B. Van Den Brandt, K. Uffmann, F. Kurdzesau, S. Jannin, J. A. Konter, P. Hautle, W. T. Wenckebach, R. Gruetter, and J. J. Van Der Klink, "Design and Performance of DNP Polarizer Coupled to a rodent MRI Scanner," *Concepts Magn. Reson. Part B Magn. Reson. Eng. An Educ. J.*, vol. 31, no. 4, pp. 255–269, 2007.

[86] L. L. Lumata, M. E. Merritt, C. R. Malloy, A. D. Sherry, J. Van Tol, L. Song, and Z. Kovacs, "Dissolution DNP-NMR spectroscopy using galvinoxyl as a polarizing agent," *J. Magn. Reson.*, vol. 227, pp. 14–19, 2013, doi: 10.1016/j.jmr.2012.11.006.

[87] L. Lumata, A. K. Jindal, M. E. Merritt, C. R. Malloy, A. D. Sherry, and Z. Kovacs, "DNP by thermal mixing under optimized conditions yields >60 000-fold enhancement of 89Y NMR signal," *J. Am. Chem. Soc.*, vol. 133, no. 22, pp. 8673–8680, 2011, doi: 10.1021/ja201880y.

[88] Y. Matsuki, T. Maly, O. Ouari, H. Karoui, F. Le Moigne, E. Rizzato, S. Lyubenova, J. Herzfeld, T. Prisner, P. Tordo, and R. G. Griffin, "Dynamic Nuclear Polarization with a Rigid Biradical," *Angew. Chemie*, vol. 121, no. 27, pp. 5096–5100, Jun. 2009, doi: 10.1002/ange.200805940.

[89] K. Adamic, D. F. Bowman, T. Gillan, and K. U. Ingold, "Kinetic Applications of Electron Paramagnetic Resonance Spectroscopy. I. Self-Reactions of Diethyl Nitroxide Radicals," *J. Am. Chem. Soc.*, vol. 93, no. 4, pp. 902–908, 1971, doi: 10.1021/ja00733a018.

[90] R. G. Hicks, "What's new in stable radical chemistry?," *Org. Biomol. Chem.*, vol. 5, no. 9, pp. 1321–1338, 2007, doi: 10.1039/b617142g.

[91] J. E. Nutting, M. Rafiee, and S. S. Stahl, "Tetramethylpiperidine N-Oxyl (TEMPO), Phthalimide N-Oxyl (PINO), and Related N-Oxyl Species: Electrochemical Properties and Their Use in Electrocatalytic Reactions," *Chem. Rev.*, vol. 118, no.
9, pp. 4834–4885, 2018, doi:
10.1021/acs.chemrev.7b00763.

[92] J. H. Ardenkjaer-Larsen, A. M. Leach, N. Clarke, J. Urbahn, D. Anderson, and T. W. Skloss, “Dynamic nuclear polarization polarizer for sterile use intent,” *NMR Biomed.*, vol. 24, no. 8, pp. 927–932, 2011, doi: 10.1002/nbm.1682.

[93] A. B. Barnes, E. Markhasin, E. Daviso, V. K. Michaelis, E. A. Nanni, S. K. Jawla, E. L. Mena, R. DeRocher, A. Thakkar, P. P. Woskov, J. Herzfeld, R. J. Temkin, and R. G. Griffin, “Dynamic nuclear polarization at 700MHz/460GHz,” *J. Magn. Reson.*, vol. 224, pp. 1–7, 2012, doi: https://doi.org/10.1016/j.jmr.2012.08.002.

[94] P. R. Jensen, S. Meier, J. H. Ardenkjaer-Larsen, J. Ø. Duus, M. Karlsson, and M. H. Lerche, “Detection of low-populated reaction intermediates with hyperpolarized NMR,” *Chem. Commun.*, no. 34, pp. 5168–5170, 2009, doi: 10.1039/B910626J.

[95] B. L. Koelsch, R. Sriram, K. R. Keshari, C. Leon Swisher, M. Van Criekinge, S. Sukumar, D. B. Vigneron, Z. J. Wang, P. E. Z. Larson, and J. Kurhanewicz, “Separation of extra- and intracellular metabolites using hyperpolarized (13)C diffusion weighted MR,” *J. Magn. Reson.*, vol. 270, pp. 115–123, Sep. 2016, doi: 10.1016/j.jmr.2016.07.002.

[96] E. Miclet, D. Abergel, A. Bornet, J. Milani, S. Jannin, and G. Bodenhausen, “Toward quantitative measurements of enzyme kinetics by dissolution dynamic nuclear polarization,” *J. Phys. Chem. Lett.*, vol. 5, no. 19, pp. 3290–3295, 2014, doi: 10.1021/jz501411d.

[97] S. Meier, M. Karlsson, P. R. Jensen, M. H. Lerche, and J. Ø. Duus, “Metabolic pathway visualization in living yeast by DNP-NMR,” *Mol. BioSyst.*, vol. 7, no. 10, pp. 2834–2836, 2011, doi: 10.1039/C1MB05202K.

[98] J. M. O. O. Vinther, V. Zhurbenko, M. M. Albannay, and J. H. Ardenkjaer-Larsen, “Design of a local quasi-distributed tuning and matching circuit for dissolution DNP cross polarization,” *Solid State Nucl. Magn. Reson.*, vol. 102, pp. 12–20, 2019, doi: 10.1016/j.ssnmr.2019.04.006.

[99] B. Aghelnejad, G. Bodenhausen, and S. Marhabaie, “A Low-Temperature Broadband NMR Probe for Multinuclear Cross-Polarization,” *ChemPhysChem*, vol. 20, no. 21, pp. 2830–2835, 2019, doi: 10.1002/cphc.201900723.

[100] O. Rybalko, S. Bowen, V. Zhurbenko, and J. H. Ardenkjaer-Larsen, “Tunable 13C/1H dual channel matching circuit for dynamic nuclear polarization system with cross-polarization,” in *2016 46th European Microwave Conference (EuMC)*, Oct. 2016, pp. 1227–1230, doi: 10.1109/EuMC.2016.7824571.

[101] M. Batel, M. Krajewski, K. Weiss, O. With, A. Däpp, A. Hunkeler, M. Gimersky, K. P. Pruessmann, P. Boesiger, B. H. Meier, S. Kozerke, and M. Ernst, “A multi-sample 94GHz dissolution dynamic-nuclear-polarization system,” *J. Magn. Reson.*, vol. 214, pp. 166–174, 2012, doi: https://doi.org/10.1016/j.jmr.2011.11.002.

[102] S. Elliott, M. Ceillier, O. Cala, Q. Chappuis, S. Cousin, and S. Jannin, “No Title,” *Prep.*, 2021.

[103] S. J. Elliott, S. F. Cousin, Q. Chappuis, O. Cala, M. Ceillier, A. Bornet, and S. Jannin, “Dipolar order

mediated \chem{^{1}H} to \chem{^{13}C} cross-polarization for dissolution-dynamic nuclear polarization,” *Magn. Reson.*, vol. 1, no. 1, pp. 89–96, 2020, doi: 10.5194/mr-1-89-2020.

[104] X.-A. Mao and C.-H. Ye, “Radiation Damping in a Simple Way,” *Concepts Magn. Reson.*, vol. 9, no. 3, pp. 173–187, Jan. 1997, doi: https://doi.org/10.1002/(SICI)1099-0534(1997)9:3<173::AID-CMR4>3.0.CO;2-W.

[105] K. J. Harris, A. Lupulescu, B. E. G. Lucier, L. Frydman, and R. W. Schurko, “Broadband adiabatic inversion pulses for cross polarization in wideline solid-state NMR spectroscopy,” *J. Magn. Reson.*, vol. 224, pp. 38–47, 2012, doi: https://doi.org/10.1016/j.jmr.2012.08.015.

[106] Q. Chappuis, S. Cousin, F. Mentink-Viger, A. Pinon, S. Elliott, O. Cala, and J. S, “No Title,” *Submitted*, 2020.

[107] S. F. J. Cox, V. Bouffard, and M. Goldman, “The coupling of two nuclear Zeeman reservoirs by the electronic spin-spin reservoir,” *J. Phys. C Solid State Phys.*, vol. 6, no. 5, 1973, doi: 10.1088/0022-3719/6/5/006.

[108] A. Gennaro, A. Karabanov, A. Potapov, and W. Köckenberger, “Heteronuclear DNP of 1H and 19F nuclei using BDPA as a polarizing agent,” *Phys. Chem. Chem. Phys.*, vol. 22, no. 15, pp. 7803–7816, 2020, doi: 10.1039/d0cp00892c.

[109] D. Guarin, S. Marhabaie, A. Rosso, D. Abergel, G. Bodenhausen, K. L. Ivanov, and D. Kurzbach, “Characterizing Thermal Mixing Dynamic Nuclear Polarization via Cross-Talk between Spin Reservoirs,” *J. Phys. Chem. Lett.*, vol. 8, no. 22, pp. 5531–5536, Nov. 2017, doi: 10.1021/acs.jpclett.7b02233.

[110] Q. Chappuis, J. Milani, B. Vuichoud, A. Bornet, A. D. Gossert, G. Bodenhausen, and S. Jannin, “Hyperpolarized water to study protein-ligand interactions,” *J. Phys. Chem. Lett.*, vol. 6, no. 9, pp. 1674–1678, 2015, doi: 10.1021/acs.jpclett.5b00403.

[111] N. N. Kuzma, P. Håkansson, M. Pourfathi, R. K. Ghosh, H. Kara, S. J. Kadlecek, G. Pileio, M. H. Levitt, and R. R. Rizi, “Lineshape-based polarimetry of dynamically-polarized 15N 2O in solid-state mixtures,” *J. Magn. Reson.*, vol. 234, pp. 90–94, 2013, doi: 10.1016/j.jmr.2013.06.008.

[112] N. S. Sullivan and R. V. Pound, “Nuclear-Spin-Lattice Relaxation of Solid Hydrogen at Low Temperatures,” *Phys. Rev. A*, vol. 6, no. 3, pp. 1102–1107, 1972, doi: 10.1017/CBO9781107415324.004.

[113] M. M. Willmering, Z. L. Ma, M. A. Jenkins, J. F. Conley, and S. E. Hayes, “Enhanced NMR with Optical Pumping Yields 75As Signals Selectively from a Buried GaAs Interface,” *J. Am. Chem. Soc.*, vol. 139, no. 11, pp. 3930–3933, 2017, doi: 10.1021/jacs.6b08970.

[114] C. M. Edwards, D. Zhou, and N. S. Sullivan, “Unusual low-temperature effects on the NMR line shapes in solid hydrogen,” *Phys. Rev. B*, vol. 43, no. 9, pp. 6540–6542, 1986, doi: 10.1097/00042560-200105010-00007.

[115] N. N. Kuzma, P. Hakansson, M. Pourfathi, R. K. Hosh, H. Kara, S. J. Kadlecek, G. Pileio, M. H. Levitt, and R. R. Rizi, “Lineshape-based polarimetry of dynamically-polarized 15N2O in solid-state mixtures,”
*J. Magn. Reson.*, vol. 234, pp. 90–94, 2013, doi: 10.1038/jid.2014.371.

[116] P. Kuhns, O. Gonen, and J. S. Waugh, “Proton spin-spin and spin-lattice relaxation in CaSO₄·xH₂O below 1 K,” *J. Magn. Reson.*, vol. 82, no. 2, pp. 231–237, 1989, doi: 10.1016/0022-2364(89)90027-9.

[117] A. Abragam, M. Chapellier, J. F. Jacquinot, and M. Goldman, “Absorption lineshape of highly polarized nuclear spin systems,” *J. Magn. Reson.*, vol. 10, no. 3, pp. 322–346, 1973, doi: 10.1016/0022-2364(73)90253-9.

[118] J. S. Waugh, O. Gonen, and P. Kuhns, “Fourier transform NMR at low temperatures,” *J. Chem. Phys.*, vol. 86, no. 7, pp. 3816–3818, 1987, doi: 10.1063/1.451940.

[119] B. Aghelnejad, S. Marhabaie, M. Baudin, and G. Bodenhausen, “Spin Thermometry: A Straightforward Measure of Millikelvin Deuterium Spin Temperatures Achieved by Dynamic Nuclear Polarization Spin Thermometry: a Straightforward Measure of Millikelvin Deuterium Spin Temperatures Achieved by Dynamic Nuclear Polarizati,” no. April, pp. 0–20, 2020, doi: 10.1021/acs.jpclett.0c00713.

[120] D. Mammoli, N. Salvi, J. Milani, R. Buratto, A. Bornet, A. A. Sehgal, E. Canet, P. Pelupessy, D. Carnevale, S. Jannin, and G. Bodenhausen, “Challenges in preparing, preserving and detecting para-water in bulk: overcoming proton exchange and other hurdles,” *Phys. Chem. Chem. Phys.*, vol. 17, no. 40, pp. 26819–26827, 2015, doi: 10.1039/c5cp03350k.

[121] V. V. Krishnan and N. Murali, “Radiation damping in modern NMR experiments: Progress and challenges,” *Prog. Nucl. Magn. Reson. Spectrosc.*, vol. 68, pp. 41–57, 2013, doi: 10.1016/j.pnmrs.2012.06.001.

[122] E. M. M. Weber, D. Kurzbach, and D. Abergel, “A DNP-hyperpolarized solid-state water NMR MASER: observation and qualitative analysis,” *Phys. Chem. Chem. Phys.*, vol. 21, no. 38, pp. 21278–21286, 2019, doi: 10.1039/c9cp03334c.

[123] C. P. Grey, L. Emsley, and M. A. Hope, “A Magic Angle Spinning Activated 17O DNP Raser Michael,” pp. 0–4, 2021, doi: 10.1021/acs.jpclett.0c03457.

[124] M. T. Pçschko, B. Vuichoud, J. Milani, A. A. Bornet, M. T. Pöschko, B. Vuichoud, J. Milani, A. A. Bornet, M. Bechmann, G. Bodenhausen, S. Jannin, and N. Müller, “Spin Noise Detection of Nuclear Hyperpolarization at 1.2 K,” *ChemPhysChem*, vol. 16, no. 18, pp. 3859–3864, Dec. 2015, doi: https://doi.org/10.1002/cphc.201500805.

[125] A. Bornet, J. Milani, B. Vuichoud, A. J. Perez Linde, G. Bodenhausen, S. Jannin, A. J. P. Linde, G. Bodenhausen, and S. Jannin, “Microwave frequency modulation to enhance Dissolution Dynamic Nuclear Polarization,” *Chem. Phys. Lett.*, vol. 602, pp. 63–67, 2014, doi: 10.1016/j.cplett.2014.04.013.

[126] Y. Hovav, A. Feintuch, S. Vega, and D. Goldfarb, “Dynamic nuclear polarization using frequency modulation at 3.34T,” *J. Magn. Reson.*, vol. 238, pp. 94–105, Jan. 2014, doi: 10.1016/j.jmr.2013.10.025.

[127] S. Jannin, A. Comment, F. Kurdzesau, J. A. Konter, P. Hautle, B. Van Den Brandt, and J. J. Van Der Klink, “A 140 GHz prepolarizer for dissolution dynamic nuclear polarization,” *J. Chem. Phys.*, vol. 128, no. 24, p. 241102, 2008, doi: 10.1063/1.2951994.

[128] F. Jähnig, G. Kwiatkowski, A. Däpp, A. Hunkeler, B. H. Meier, S. Kozerke, and M. Ernst, “Dissolution DNP using trityl radicals at 7 T field,” *Phys. Chem. Chem. Phys.*, vol. 19, no. 29, pp. 19196–19204, 2017, doi: 10.1039/c7cp03633g.

[129] S. Jannin, A. Bornet, R. Melzi, and G. Bodenhausen, “High field dynamic nuclear polarization at 6.7 T: Carbon-13 polarization above 70% within 20 min,” *Chem. Phys. Lett.*, vol. 549, pp. 99–102, 2012, doi: 10.1016/j.cplett.2012.08.017.

[130] J. H. Ardenkjær-Larsen, S. Bowen, J. R. Petersen, O. Rybalko, M. S. Vinding, M. Ullisch, and N. C. Nielsen, “Cryogen-free dissolution dynamic nuclear polarization polarizer operating at 3.35 T, 6.70 T, and 10.1 T,” *Magn. Reson. Med.*, vol. 81, no. 3, pp. 2184–2194, Mar. 2019, doi: 10.1002/mrm.27537.

[131] F. Kurdzesau, B. Van Den Brandt, A. Comment, P. Hautle, S. Jannin, J. J. Van Der Klink, and J. A. Konter, “Dynamic nuclear polarization of small labelled molecules in frozen water-alcohol solutions,” *J. Phys. D. Appl. Phys.*, vol. 41, no. 15, pp. 155506–10, 2008, doi: 10.1088/0022-3727/41/15/155506.

[132] J. H. Ardenkjaer-Larsen, S. MacHoll, and H. Jóhannesson, “Dynamic nuclear polarization with trityls at 1.2 K,” *Appl. Magn. Reson.*, vol. 34, no. 3–4, pp. 509–522, 2008, doi: 10.1007/s00723-008-0134-4.

[133] L. L. Lumata, S. J. Ratnakar, A. K. Jindal, M. E. Merritt, A. Comment, C. R. Malloy, A. D. Sherry, Z. Kovacs, S. James Ratnakar, A. K. Jindal, M. E. Merritt, A. Comment, C. R. Malloy, A. D. Sherry, Z. Kovacs, S. J. Ratnakar, A. K. Jindal, M. E. Merritt, A. Comment, C. R. Malloy, A. D. Sherry, and Z. Kovacs, “BDPA: An Efficient Polarizing Agent for Fast Dissolution Dynamic Nuclear Polarization NMR,” *Natl. Inst. Heal.*, vol. 17, no. 39, pp. 10825–7, Sep. 2011, doi: 10.1002/chem.201102037.BDPA.

[134] A. J. Perez Linde, “Application of cross polarisation techniques to dynamic nuclear polarisation dissolution experiments,” no. November, 2010, [Online]. Available: http://etheses.nottingham.ac.uk/1417/.

[135] M. Batel, A. Däpp, A. Hunkeler, B. H. Meier, S. Kozerke, and M. Ernst, “Cross-polarization for dissolution dynamic nuclear polarization,” *Phys. Chem. Chem. Phys.*, vol. 16, no. 39, pp. 21407–21416, 2014, doi: 10.1039/c4cp02696a.

[136] A. Dey, B. Charrier, E. Martineau, C. Deborde, E. Gandriau, A. Moing, D. Jacob, D. Eshchenko, M. Schnell, R. Melzi, D. Kurzbach, M. Ceillier, Q. Chappuis, S. F. Cousin, J. G. Kempf, S. Jannin, J.-N. Dumez, and P. Giraudeau, “Hyperpolarized NMR Metabolomics at Natural 13 C Abundance,” *Anal. Chem.*, vol. 92, pp. 14867–14871, 2020, doi: 10.1021/acs.analchem.0c03510.

[137] J. N. Dumez, J. Milani, B. Vuichoud, A. Bornet, J. Lalande-Martin, I. Tea, M. Yon, M. Maucourt, C. Deborde, A. Moing, L. Frydman, G. Bodenhausen, S. Jannin, and P. Giraudeau, “Hyperpolarized NMR of plant and cancer cell extracts at natural abundance,” *Analyst*, vol. 140, no. 17, pp. 5860–5863, 2015, doi: 10.1039/c5an01203a.

[138] B. Vuichoud, J. Milani, A. Bornet, R. Melzi, S. Jannin, and G. Bodenhausen, “Hyperpolarization of deuterated metabolites via remote cross-polarization and dissolution dynamic nuclear polarization,” *J. Phys.*
*Chem. B*, vol. 118, no. 5, pp. 1411–1415, 2014, doi: 10.1021/jp4118776.

[139] S. J. Elliott, S. F. Cousin, Q. Chappuis, O. Cala, M. Ceillier, A. Bornet, and S. Jannin, "Dipolar order mediated 1H → 13C cross-polarization for dissolution-dynamic nuclear polarization," *Magn. Reson.*, vol. 1, no. 1, pp. 89–96, 2020, doi: 10.5194/mr-1-89-2020.

[140] A. Bornet, "De l'usage des protons hyperpolarisés pour augmenter la sensibilite de la RMN," vol. 6581, 2015.

[141] A. Kiswandhi, P. Niedbalski, C. Parish, P. Kaur, A. Martins, L. Fidelino, C. Khemtong, L. Song, A. D. Sherry, and L. Lumata, "Impact of Ho3⁺-doping on 13C dynamic nuclear polarization using trityl OX063 free radical," *Phys. Chem. Chem. Phys.*, vol. 18, no. 31, pp. 21351–21359, 2016, doi: 10.1039/c6cp03954e.

[142] R. Rogawski, I. V. Sergeyev, Y. Zhang, T. H. Tran, Y. Li, L. Tong, and A. E. McDermott, "NMR Signal Quenching from Bound Biradical Affinity Reagents in DNP Samples," *J. Phys. Chem. B*, vol. 121, no. 48, pp. 10770–10781, 2017, doi: 10.1021/acs.jpcb.7b08274.

[143] S. Hediger, D. Lee, F. Mentink-Vigier, and G. De Paëpe, *MAS-DNP enhancements: Hyperpolarization, depolarization, and absolute sensitivity*, vol. 7, no. 4. 2018.

[144] S. Elliott, I. Koptyug, and S. Jannin, "No Title," *Prep.*, 2021.

[145] R. M. Malinowski, K. W. Lipsø, M. H. Lerche, and J. H. Ardenkjaer-Larsen, "Dissolution Dynamic Nuclear Polarization capability study with fluid path," *J. Magn. Reson.*, vol. 272, pp. 141–146, 2016, doi: 10.1016/j.jmr.2016.09.015.

[146] A. Capozzi, M. Karlsson, J. R. Petersen, M. H. Lerche, and J. H. Ardenkjaer-Larsen, "Liquid-State 13C Polarization of 30% through Photoinduced Nonpersistent Radicals," *J. Phys. Chem. C*, vol. 122, no. 13, pp. 7432–7443, 2018, doi: 10.1021/acs.jpcc.8b01482.

[147] A. C. Pinon, A. Capozzi, and J. H. Ardenkjaer-Larsen, "Hyperpolarized water through dissolution dynamic nuclear polarization with UV-generated radicals," *Commun. Chem. 2020* 31, vol. 3, no. 1, pp. 1–9, 2020, doi: 10.1038/s42004-020-0301-6.

[148] M. Krajewski, P. Wespi, J. Busch, L. Wissmann, G. Kwiatkowski, J. Steinhauser, M. Batel, M. Ernst, and S. Kozerke, "A multisample dissolution dynamic nuclear polarization system for serial injections in small animals," *Magn. Reson. Med.*, vol. 77, no. 2, pp. 904–910, 2017, doi: 10.1002/mrm.26147.

[149] T. Cheng, A. P. Gaunt, I. Marco-Rius, M. Gehrung, A. P. Chen, J. J. Klink, A. Comment, I. Marco-Rius, M. Gehrung, A. P. Chen, J. J. van der Klink, and A. Comment, "A multisample 7 T dynamic nuclear polarization polarizer for preclinical hyperpolarized MR," *NMR Biomed.*, no. October 2019, pp. 1–10, Jan. 2020, doi: 10.1002/nbm.4264.

[150] S. Bowen and J. H. Ardenkjaer-Larsen, "Enhanced performance large volume dissolution-DNP," *J. Magn. Reson.*, vol. 240, pp. 90–94, 2014, doi: 10.1016/j.jmr.2014.01.009.

[151] J. Jain, S. Dey, L. Muralidharan, A. M. Leach, and J. H. Ardenkjaer-Larsen, "Jet Impingement Melting With Vaporization: A Numerical Study," in *Heat Transfer*:

*Volume 2*, Jan. 2008, vol. 2, pp. 559–567, doi: 10.1115/HT2008-56148.

[152] N. (US) Jan Henrik Ardenkjaer-larsen, Amersham (GB); David Dietrich, Niskayuna, NY (US); Karl Andreas Gram, Oslo (NO); Andrew M. Leach, Clifton Park, NY (US); Peter Miller, New London, CT (US); Eric J. Telfeyan, Guilderland, NY (US); Mikkel Thaning, Oslo (NO); Da, "Patent - NOZZLE FOR DNP POLARIZER," vol. 1, no. 5, pp. 739–740, 2011.

[153] D. M. Wilson, K. R. Keshari, P. E. Z. Larson, A. P. Chen, S. Hu, M. Van Criekinge, R. Bok, S. J. Nelson, J. M. MacDonald, D. B. Vigneron, and J. Kurhanewicz, "Multi-compound polarization by DNP allows simultaneous assessment of multiple enzymatic activities in vivo," *J. Magn. Reson.*, vol. 205, no. 1, pp. 141–147, 2010, doi: 10.1016/j.jmr.2010.04.012.

[154] A. Bornet, M. Maucourt, C. Deborde, D. Jacob, J. Milani, B. Vuichoud, X. Ji, J. N. Dumez, A. Moing, G. Bodenhausen, S. Jannin, and P. Giraudeau, "Highly Repeatable Dissolution Dynamic Nuclear Polarization for Heteronuclear NMR Metabolomics," *Anal. Chem.*, vol. 88, no. 12, pp. 6179–6183, 2016, doi: 10.1021/acs.analchem.6b01094.

[155] X. Ji, A. A. Bornet, B. Vuichoud, J. Milani, D. Gajan, A. J. A. J. Rossini, L. Emsley, G. Bodenhausen, and S. Jannin, "Transportable hyperpolarized metabolites," *Nat. Commun.*, vol. 8, no. 1, p. 13975, Apr. 2017, doi: 10.1038/ncomms13975.

[156] J. Granwehr, R. Panek, J. Leggett, and W. Köckenberger, "Quantifying the transfer and settling in NMR experiments with sample shuttling," *J. Chem. Phys.*, vol. 132, no. 24, p. 244507, Jun. 2010, doi: 10.1063/1.3446804.

[157] T. Harris, C. Bretschneider, and L. Frydman, "Dissolution DNP NMR with solvent mixtures: Substrate concentration and radical extraction," *J. Magn. Reson.*, vol. 211, no. 1, pp. 96–100, 2011, doi: 10.1016/j.jmr.2011.04.001.

[158] S. G. J. Van Meerten, G. E. Janssen, and A. P. M. Kentgens, "Experiments Rapid-melt DNP for Multidimensional and Heteronuclear High-field NMR Experiments," *J. Magn. Reson.*, p. 106656, 2019, doi: 10.1016/j.jmr.2019.106656.

[159] S. Bowen and C. Hilty, "Rapid sample injection for hyperpolarized NMR spectroscopy," *Phys. Chem. Chem. Phys.*, vol. 12, no. 22, pp. 5766–5770, May 2010, doi: 10.1039/c002316g.

[160] S. Katsikis, I. Marin-Montesinos, M. Pons, C. Ludwig, and U. L. Günther, "Improved Stability and Spectral Quality in Ex Situ Dissolution DNP Using an Improved Transfer Device," *Appl. Magn. Reson.*, vol. 46, no. 7, pp. 723–729, 2015, doi: 10.1007/s00723-015-0680-5.

[161] G. Olsen, E. Markhasin, O. Szekely, C. Bretschneider, and L. Frydman, "Optimizing water hyperpolarization and dissolution for sensitivity-enhanced 2D biomolecular NMR," *J. Magn. Reson.*, vol. 264, pp. 49–58, 2016, doi: 10.1016/j.jmr.2016.01.005.

[162] K. A. Triplett, S. M. Ghiaasiaan, S. I. Abdel-Khalik, and D. L. Sadowski, "Gas-liquid two-phase flow in microchannels Part I: two-phase flow patterns," *Int. J. Multiph. Flow*, vol. 25, no. 3, pp. 377–394, Apr. 1999, doi: 10.1016/S0301-9322(98)00054-8.

[163] J. Kim, J. D. O'Neill, N. V. Dorrello, M. Bacchetta,
and G. Vunjak-Novakovic, "Targeted delivery of liquid microvolumes into the lung," *Proc. Natl. Acad. Sci.*, vol. 112, no. 37, pp. 11530–11535, 2015, doi: 10.1073/pnas.1512613112.

[164] H. Fujioka and J. B. Grotberg, "The steady propagation of a surfactant-laden liquid plug in a two-dimensional channel," *Phys. Fluids*, vol. 17, no. 8, pp. 1–17, 2005, doi: 10.1063/1.1948907.

[165] K. J. Cassidy, N. Gavriely, and J. B. Grotberg, "Liquid Plug Flow in Straight and Bifurcating Tubes," *J. Biomech. Eng.*, vol. 123, no. 6, p. 580, 2002, doi: 10.1115/1.1406949.

[166] J. C. Magniez, M. Baudoin, C. Liu, and F. Zoueshtiagh, "Dynamics of liquid plugs in prewetted capillary tubes: From acceleration and rupture to deceleration and airway obstruction," *Soft Matter*, vol. 12, no. 42, pp. 8710–8717, 2016, doi: 10.1039/c6sm01463a.

[167] H. Y. Chen and C. Hilty, "Implementation and Characterization of Flow Injection in Dissolution Dynamic Nuclear Polarization NMR Spectroscopy," *ChemPhysChem*, vol. 16, no. 12, pp. 2646–2652, Aug. 2015, doi: 10.1002/cphc.201500292.

[168] H. Y. Chen and C. Hilty, "Hyperpolarized Hadamard spectroscopy using flow NMR," *Anal. Chem.*, vol. 85, no. 15, pp. 7385–7390, Aug. 2013, doi: 10.1021/ac401293n.

[169] J. E. Austin and J. R. Palfrey, "Mixing of Miscible but Dissimilar Liquids in Serial Flow in a Pipeline," *Proc. Inst. Mech. Eng.*, vol. 178, no. 1, pp. 377–389, Jun. 1963, doi: 10.1177/002034836317800160.

[170] L. Zhao, J. Derksen, and R. Gupta, "Simulations of axial mixing of liquids in a long horizontal pipe for industrial applications," *Energy and Fuels*, vol. 24, no. 11, pp. 5844–5850, 2010, doi: 10.1021/ef100846r.

[171] A. R. Patrachari and A. H. Johannes, "A conceptual framework to model interfacial contamination in multiproduct petroleum pipelines," *Int. J. Heat Mass Transf.*, vol. 55, no. 17–18, pp. 4613–4620, 2012, doi: 10.1016/j.ijheatmasstransfer.2012.04.017.

[172] G. He, M. Lin, B. Wang, Y. Liang, and Q. Huang, "Experimental and numerical research on the axial and radial concentration distribution feature of miscible fluid interfacial mixing process in products pipeline for industrial applications," *Int. J. Heat Mass Transf.*, vol. 127, pp. 728–745, 2018, doi: 10.1016/j.ijheatmasstransfer.2018.08.080.

[173] E. Chiavazza, E. Kubala, C. V. Gringeri, S. Düwel, M. Durst, R. F. Schulte, and M. I. Menzel, "Earth's magnetic field enabled scalar coupling relaxation of 13C nuclei bound to fast-relaxing quadrupolar 14N in amide groups," *J. Magn. Reson.*, vol. 227, pp. 35–38, 2013, doi: 10.1016/j.jmr.2012.11.016.

[174] G. D. Reed, C. Von Morze, R. Bok, B. L. Koelsch, M. Van Criekinge, K. J. Smith, H. Shang, P. E. Z. Larson, J. Kurhanewicz, and D. B. Vigneron, "High resolution 13C MRI with hyperpolarized urea: In vivo T 2 mapping and 15N labeling effects," *IEEE Trans. Med. Imaging*, vol. 33, no. 2, pp. 362–371, 2014, doi: 10.1109/TMI.2013.2285120.

[175] H. Shang, T. Skloss, C. von Morze, L. Carvajal, M. Van Criekinge, E. Milshteyn, P. E. Z. Larson, R. E. Hurd, and D. B. Vigneron, "Handheld electromagnet carrier for transfer of hyperpolarized carbon-13

samples," *Magn. Reson. Med.*, vol. 75, no. 2, pp. 917–922, Feb. 2016, doi: 10.1002/mrm.25657.

[176] P. Berthault, C. Boutin, C. Martineau-Corcos, and G. Carret, "Use of dissolved hyperpolarized species in NMR: practical considerations," *Prog. Nucl. Magn. Reson. Spectrosc.*, vol. 118–119, pp. 74–90, 2020, doi: 10.1016/j.pnmrs.2020.03.002.

[177] A. S. Kiryutin, B. A. Rodin, A. V. Yurkovskaya, K. L. Ivanov, D. Kurzbach, S. Jannin, D. Guarin, D. Abergel, and G. Bodenhausen, "Transport of hyperpolarized samples in dissolution-DNP experiments," *Phys. Chem. Chem. Phys.*, vol. 21, no. 25, pp. 13696–13705, 2019, doi: 10.1039/c9cp02600b.

[178] A. Abragam and A. Abragam, *The principles of nuclear magnetism*, no. 32. Oxford university press, 1961.

[179] J. Kowalewski and L. Mäler, *Nuclear Spin Relaxation in Liquids: Theory, Experiments and Applications*. 2006.

[180] J. Cavanagh, W. J. Fairbrother, A. G. Palmer III, M. Rance, and N. J. Skelton, *Protein NMR Spectroscopy: Principles and Practice*. 1995.

[181] M. H. Levitt, *Spin Dynamics: Basics of Nuclear Magnetic Resonance*. 2001.

[182] P. J. Hore, *Nuclear Magnetic Resonance*. 1995.

[183] P. J. Hore, J. A. Jones, and S. Wimperis, *The Toolkit: How Pulse Sequences Work*. 2015.

[184] N. Bloembergen, "On the interaction of nuclear spins in a crystalline lattice," *Physica*, vol. XV, no. 3–4, pp. 176–219, 1949, doi: 10.1142/9789812795809_0005.

[185] C. Ramanathan, "Dynamic Nuclear Polarization and Spin Diffusion in Nonconducting Solids," *Appl. Magn. Reson.*, vol. 34, pp. 409–421, 2008, doi: 10.1007/s00723-008-0123-7.

[186] A. J. Pell, G. Pintacuda, and C. P. Grey, "Paramagnetic NMR in solution and the solid state," *Prog. Nucl. Magn. Reson. Spectrosc.*, vol. 111, pp. 1–271, 2019, doi: 10.1016/j.pnmrs.2018.05.001.

[187] Y. Hovav, A. Feintuch, and S. Vega, "Theoretical aspects of dynamic nuclear polarization in the solid state - Spin temperature and thermal mixing," *Phys. Chem. Chem. Phys.*, vol. 15, no. 1, pp. 188–203, 2013, doi: 10.1039/c2cp42897k.

[188] A. Karabanov, G. Kwiatkowski, and W. Köckenberger, "Spin dynamic simulations of solid effect DNP: The role of the relaxation superoperator," *Mol. Phys.*, vol. 112, no. 14, pp. 1838–1854, 2014, doi: 10.1080/00268976.2014.884287.

[189] D. Wišniewski, A. Karabanov, I. Lesanovsky, and W. Köckenberger, "Solid effect DNP polarization dynamics in a system of many spins," *J. Magn. Reson.*, vol. 264, pp. 30–38, 2016, doi: 10.1016/j.jmr.2016.01.016.

[190] G. R. Khutsishvili, "Spin diffusion," *Sov. Phys. Uspekhi*, vol. 8, no. 6, pp. 743–769, 1966.

[191] R. L. R. R. L. R. L. Vold and R. L. R. R. L. R. R. L. Vold, "Nuclear magnetic relaxation in coupled spin systems," *Prog. Nucl. Magn. Reson. Spectrosc.*, vol. 12, no. 2, pp. 79–133, 1978, doi: https://doi.org/10.1016/0079-6565(78)80004-1.

[192] L. G. Werbelow and D. M. Grant, "Carbon-13 relaxation in multispin systems of the type AXn," *J. Chem. Phys.*, vol. 63, no. 1, pp. 544–556, 1975, doi: 10.1063/1.431085.
[193] G. E. Pake, “Nuclear Resonance Absorption in Hydrated Crystals: Fine Structure of the Proton Line,” *J. Chem. Phys.*, vol. 16, no. 4, pp. 327–336, 1948.

[194] Z. H. Endre, B. E. Chapman, and P. W. Kuchel, “Intraerythrocyte microviscosity and diffusion of specifically labelled [glycyl-alpha-13C]glutathione by using 13C n.m.r.,” *Biochem. J.*, vol. 216, no. 3, pp. 655–660, Dec. 1983, doi: 10.1042/bj2160655.

[195] B. Erriah and S. J. Elliott, “Experimental evidence for the role of paramagnetic oxygen concentration on the decay of long-lived nuclear spin order,” *RSC Adv.*, vol. 9, no. 40, pp. 23418–23424, 2019, doi: 10.1039/C9RA03748A.

[196] K. W. Lipsø, S. Bowen, O. Rybalko, and J. H. Ardenkjær-Larsen, “Large dose hyperpolarized water with dissolution-DNP at high magnetic field,” *J. Magn. Reson.*, vol. 274, pp. 65–72, 2017, doi: 10.1016/j.jmr.2016.11.008.

[197] D. Shishmarev, P. W. Kuchel, G. Pagès, A. J. Wright, R. L. Hesketh, F. Kreis, and K. M. Brindle, “Glyoxalase activity in human erythrocytes and mouse lymphoma, liver and brain probed with hyperpolarized 13C-methylglyoxal,” *Commun. Biol.*, vol. 1, no. 1, p. 232, 2018, doi: 10.1038/s42003-018-0241-1.

[198] D. Kruk, R. Meier, and E. A. Rössler, “Nuclear magnetic resonance relaxometry as a method of measuring translational diffusion coefficients in liquids,” *Phys. Rev. E - Stat. Nonlinear, Soft Matter Phys.*, vol. 85, no. 2, pp. 1–5, 2012, doi: 10.1103/PhysRevE.85.020201.

[199] B. Borah and R. G. Bryant, “NMR relaxation dispersion in an aqueous nitroxide system,” *J. Chem. Phys.*, vol. 75, no. 7, pp. 3297–3300, 1981, doi: 10.1063/1.442480.

[200] D. Baudouin, H. A. Van Kalkeren, A. Bornet, B. Vuichoud, L. Veyre, M. Cavaillès, M. Schwarzwälder, W.-C. C. Liao, D. Gajan, G. Bodenhausen, L. Emsley, A. Lesage, S. Jannin, C. Copéret, and C. Thieuleux, “Cubic three-dimensional hybrid silica solids for nuclear hyperpolarization,” *Chem. Sci.*, vol. 7, no. 11, pp. 6846–6850, Oct. 2016, doi: 10.1039/c6sc02055k.

[201] R. Nepravishta, B. Yu, and J. Iwahara, “Hydrogen-exchange kinetics studied through analysis of self-decoupling of nuclear magnetic resonance,” *J. Magn. Reson.*, vol. 312, p. 106687, 2020, doi: 10.1016/j.jmr.2020.106687.

[202] P. Bernatowicz, D. Kubica, M. Ociepa, A. Wodyński, and A. Gryff-Keller, “Scalar relaxation of the second kind. A potential source of information on the dynamics of molecular movements. 4. Molecules with collinear C-H and C-Br bonds,” *J. Phys. Chem. A*, vol. 118, no. 23, pp. 4063–4070, 2014, doi: 10.1021/jp5037298.

[203] J. N. Dumez, P. Håkansson, S. Mamone, B. Meier, G. Stevanato, J. T. Hill-Cousins, S. S. Roy, R. C. D. Brown, G. Pileio, and M. H. Levitt, “Theory of long-lived nuclear spin states in methyl groups and quantum-rotor induced polarisation,” *J. Chem. Phys.*, vol. 142, no. 4, 2015, doi: 10.1063/1.4906273.

[204] T. E. Burke and S. I. Chan, “Nuclear spin relaxation in the presence of internal rotation II. Nuclear-spin-internal rotational coupling in benzotrifluoride and hexafluorobutyne-2,” *J. Magn. Reson.*, vol. 2, no. 2, pp. 120–140, 1970, doi: 10.1016/0022-2364(70)90063-6.

[205] G. B. Matson, “Methyl NMR relaxation: The effects of spin rotation and chemical shift anisotropy mechanisms,” *J. Chem. Phys.*, vol. 67, no. 11, pp. 5152–5161, 1977, doi: 10.1063/1.434744.

[206] T. E. Bull, “Extended diffusion of a symmetric top molecule with internal rotation,” *J. Chem. Phys.*, vol. 65, no. 11, pp. 4802–4815, 1976, doi: 10.1063/1.432951.

[207] A. S. Dubin and S. I. Chan, “Nuclear-Spin—Internal-Rotation Coupling,” *J. Chem. Phys.*, vol. 46, no. 11, pp. 4533–4535, 1967, doi: 10.1063/1.1840583.

[208] B. F. Melton, V. L. Pollak, T. W. Mayes, and B. L. Willis, “Condition for Sudden Passage in the Earth’s-Field NMR Technique,” *J. Magn. Reson. Ser. A*, vol. 117, no. 2, pp. 164–170, 1995, doi: 10.1006/jmra.1995.0732.

[209] M. Carravetta, O. G. Johannessen, and M. H. Levitt, “Beyond the T1 Limit: Singlet Nuclear Spin States in Low Magnetic Fields,” *Phys. Rev. Lett.*, vol. 92, no. 15, p. 153003, Apr. 2004, doi: 10.1103/PhysRevLett.92.153003.

[210] J. W. Blanchard and D. Budker, “Zero-to ultralow-field NMR,” *eMagRes*, vol. 5, no. 3, pp. 1395–1410, 2016, doi: 10.1002/9780470034590.emrstm1369.

[211] C. R. Bowers and D. P. Weitekamp, “Parahydrogen and Synthesis Allow Dramatically Enhanced Nuclear Alignment,” *J. Am. Chem. Soc.*, vol. 109, no. 18, pp. 5541–5542, 1987, doi: 10.1021/ja00252a049.

[212] K. Miesel, K. L. Ivanov, A. V. Yurkovskaya, and H. M. Vieth, “Coherence transfer during field-cycling NMR experiments,” *Chem. Phys. Lett.*, vol. 425, no. 1–3, pp. 71–76, 2006, doi: 10.1016/j.cplett.2006.05.025.

[213] J. Eills, J. W. Blanchard, T. Wu, C. Bengs, J. Hollenbach, D. Budker, and M. H. Levitt, “Polarization transfer via field sweeping in parahydrogen-enhanced nuclear magnetic resonance,” *J. Chem. Phys.*, vol. 150, no. 17, p. 174202, 2019, doi: 10.1063/1.5089486.

[214] H. Zeng, Y. Lee, and C. Hilty, “Quantitative rate determination by dynamic nuclear polarization enhanced NMR of a diels-alder reaction,” *Anal. Chem.*, vol. 82, no. 21, pp. 8897–8902, 2010, doi: 10.1021/ac101670n.

[215] Y. Lee, G. S. Heo, H. F. Zeng, K. L. Wooley, and C. Hilty, “Detection of living anionic species in polymerization reactions using hyperpolarized NMR,” *J. Am. Chem. Soc.*, vol. 135, no. 12, pp. 4636–4639, 2013, doi: 10.1021/ja4001008.

[216] C. H. Chen, W. C. Shih, and C. Hilty, “In situ determination of tacticity, deactivation, and kinetics in [rac-(C2H4(1-Indenyl)2)ZrMe][B(C6F5)4] and [Cp2ZrMe][B(C6F5)4]-Catalyzed Polymerization of 1-Hexene Using 13C hyperpolarized nmr,” *J. Am. Chem. Soc.*, vol. 137, no. 21, pp. 6965–6971, 2015, doi: 10.1021/jacs.5b04479.

[217] M. J. Moure, Y. Zhuo, G. J. Boons, and J. H. Prestegard, “Perdeuterated and 13C-enriched myositol for DNP assisted monitoring of enzymatic phosphorylation by inositol-3-kinase,” *Chem. Commun.*, vol. 53, no. 92, pp. 12398–12401, 2017, doi: 10.1039/c7cc07023c.

[218] S. Bowen and C. Hilty, “Time-resolved dynamic
nuclear polarization enhanced NMR spectroscopy,”
Angew. Chemie - Int. Ed., vol. 47, no. 28, pp. 5235–
5237, 2008, doi: 10.1002/anie.200801492.

[219] Y. Lee, H. Zeng, S. Ruedisser, A. D. Gossert, and C. Hilty, “Nuclear magnetic resonance of hyperpolarized fluorine for characterization of protein-ligand interactions,” *J. Am. Chem. Soc.*, vol. 134, no. 42, pp. 17448–17451, 2012, doi: 10.1021/ja308437h.

[220] Y. Kim and C. Hilty, *Applications of Dissolution-DNP for NMR Screening*, 1st ed., vol. 615. Elsevier Inc., 2019.

[221] Y. Kim and C. Hilty, “Affinity screening using competitive binding with fluorine-19 hyperpolarized ligands,” *Angew. Chemie - Int. Ed.*, vol. 54, no. 16, pp. 4941–4944, 2015, doi: 10.1002/anie.201411424.

[222] P. R. Jensen, M. Karlsson, M. H. Lerche, and S. Meier, "Real-Time DNP** NMR Observations of Acetic Acid Uptake, Intracellular Acidification, and of Consequences for Glycolysis and Alcoholic Fermentation in Yeast," *Chem. - A Eur. J.*, vol. 19, no. 40, pp. 13288–13293, 2013, doi: 10.1002/chem.201302429.

[223] H. Zeng, S. Bowen, and C. Hilty, “Sequentially acquired two-dimensional NMR spectra from hyperpolarized sample,” *J. Magn. Reson.*, vol. 199, no. 2, pp. 159–165, Aug. 2009, doi: 10.1016/j.jmr.2009.04.011.

[224] P. Giraudeau and L. Frydman, “Ultrafast 2D NMR: An emerging tool in analytical spectroscopy,” *Annu. Rev. Anal. Chem.*, vol. 7, pp. 129–161, 2014, doi: 10.1146/annurev-anchem-071213-020208.

[225] L. Frydman, T. Scherf, and A. Lupulescu, “The acquisition of multidimensional NMR spectra within a single scan,” *Proc. Natl. Acad. Sci. U. S. A.*, vol. 99, no. 25, pp. 15858–15862, 2002, doi: 10.1073/pnas.252644399.

[226] J. Dumez, “Spatial encoding and spatial selection methods in high-resolution NMR spectroscopy,” *Prog. Nucl. Magn. Reson. Spectrosc.*, 2018, doi: 10.1016/j.pnmrs.2018.08.001.

[227] L. Frydman and D. Blazina, “Ultrafast two-dimensional nuclear magnetic resonance spectroscopy of hyperpolarized solutions,” *Nat. Phys.*, vol. 3, no. 6, pp. 415–419, Jun. 2007, doi: 10.1038/nphys597.

[228] M. Mishkovsky and L. Frydman, “Progress in hyperpolarized ultrafast 2D NMR spectroscopy,” *ChemPhysChem*, vol. 9, no. 16, pp. 2340–2348, 2008, doi: 10.1002/cphc.200800461.

[229] P. Giraudeau, Y. Shrot, and L. Frydman, “Multiple ultrafast, broadband 2D NMR spectra of hyperpolarized natural products,” *J. Am. Chem. Soc.*, vol. 131, no. 39, pp. 13902–13903, Oct. 2009, doi: 10.1021/ja905096f.

[230] G. Zhang, S. Ahola, M. H. Lerche, V. V. Telkki, and C. Hilty, “Identification of Intracellular and Extracellular Metabolites in Cancer Cells Using 13C Hyperpolarized Ultrafast Laplace NMR,” *Anal. Chem.*, vol. 90, no. 18, pp. 11131–11137, 2018, doi: 10.1021/acs.analchem.8b03096.

[231] S. Ahola, V. V. Zhivonitko, O. Mankinen, G. Zhang, A. M. Kantola, H. Y. Chen, C. Hilty, I. V. Koptyug, and V. V. Telkki, “Ultrafast multidimensional Laplace NMR for a rapid and sensitive chemical analysis,” *Nat. Commun.*, vol. 6, pp. 1–7, 2015, doi:

10.1038/ncomms9363.

[232] L. Guduff, D. Kurzbach, C. van Heijenoort, D. Abergel, and J. N. Dumez, “Single-Scan 13C Diffusion-Ordered NMR Spectroscopy of DNP-Hyperpolarised Substrates,” *Chem. - A Eur. J.*, vol. 23, no. 66, pp. 16722–16727, Nov. 2017, doi: 10.1002/chem.201703300.

[233] R. Panek, J. Granwehr, J. Leggett, and W. Köckenberger, “Slice-selective single scan proton COSY with dynamic nuclear polarisation,” *Phys. Chem. Chem. Phys.*, vol. 12, no. 22, p. 5771, May 2010, doi: 10.1039/c002710n.

[234] P. Schanda and B. Brutscher, “Very fast two-dimensional NMR spectroscopy for real-time investigation of dynamic events in proteins on the time scale of seconds,” *J. Am. Chem. Soc.*, vol. 127, no. 22, pp. 8014–8015, 2005, doi: 10.1021/ja051306e.

[235] D. Kurzbach, E. Canet, A. G. Flamm, A. Jhajharia, E. M. M. Weber, R. Konrat, and G. Bodenhausen, “Investigation of Intrinsically Disordered Proteins through Exchange with Hyperpolarized Water,” *Angew. Chemie - Int. Ed.*, vol. 56, no. 1, pp. 389–392, 2017, doi: 10.1002/anie.201608903.

[236] Y. Wang, J. Kim, and C. Hilty, “Determination of protein-ligand binding modes using fast multidimensional NMR with hyperpolarization,” *Chem. Sci.*, vol. 11, no. 23, pp. 5935–5943, 2020, doi: 10.1039/d0sc00266f.

[237] P. Kadeřávek, F. Ferrage, G. Bodenhausen, and D. Kurzbach, “High-Resolution NMR of Folded Proteins in Hyperpolarized Physiological Solvents,” *Chem. - A Eur. J.*, vol. 24, no. 51, pp. 13418–13423, 2018, doi: 10.1002/chem.201802885.

[238] S. J. Elliott, B. Meier, B. Vuichoud, G. Stevanato, L. J. Brown, J. Alonso-Valdesueiro, L. Emsley, S. Jannin, and M. H. Levitt, “Hyperpolarized long-lived nuclear spin states in monodeuterated methyl groups,” *Phys. Chem. Chem. Phys.*, vol. 20, no. 15, pp. 9755–9759, 2018, doi: 10.1039/C8CP00253C.

[239] A. Bornet, S. Jannin, J. A. Konter, P. Hautle, B. Van Den Brandt, and G. Bodenhausen, “Ultra high-resolution NMR: Sustained induction decays of long-lived coherences,” *J. Am. Chem. Soc.*, vol. 133, no. 39, pp. 15644–15649, 2011, doi: 10.1021/ja2052792.

[240] A. Bornet, S. Jannin, and G. Bodenhausen, “Three-field NMR to preserve hyperpolarized proton magnetization as long-lived states in moderate magnetic fields,” *Chem. Phys. Lett.*, vol. 512, no. 4–6, pp. 151–154, 2011, doi: 10.1016/j.cplett.2011.07.015.

[241] P. R. Vasos, A. Comment, R. Sarkar, P. Ahuja, S. Jannin, J.-P. Ansermet, J. A. Konter, P. Hautle, B. van den Brandt, and G. Bodenhausen, “Long-lived states to sustain hyperpolarized magnetization,” *Proc. Natl. Acad. Sci.*, vol. 106, no. 44, pp. 18469–18473, 2009, doi: 10.1073/pnas.0908123106.

[242] R. Buratto, A. Bornet, J. Milani, D. Mammoli, B. Vuichoud, N. Salvi, M. Singh, A. Laguerre, S. Passemard, S. Gerber-Lemaire, S. Jannin, and G. Bodenhausen, “Drug screening boosted by hyperpolarized long-lived states in NMR,” *ChemMedChem*, vol. 9, no. 11, pp. 2509–2515, 2014, doi: 10.1002/cmdc.201402214.

[243] K. Golman, J. H. Ardenkjaer-Larsen, J. S. Petersson, S. Mansson, and I. Leunbach, “Molecular imaging
with endogenous substances,” *Proc. Natl. Acad. Sci.*, vol. 100, no. 18, pp. 10435–10439, Sep. 2003, doi: 10.1073/pnas.1733836100.

[244] K. Golman, R. in 't Zandt, and M. Thaning, “Real-time metabolic imaging,” *Proc. Natl. Acad. Sci.*, vol. 103, no. 30, pp. 11270–11275, Jul. 2006, doi: 10.1073/pnas.0601319103.

[245] K. Golman, R. I. t. Zandt, M. Lerche, R. Pehrson, and J. H. Ardenkjaer-Larsen, “Metabolic imaging by hyperpolarized 13C magnetic resonance imaging for in vivo tumor diagnosis,” *Cancer Res.*, vol. 66, no. 22, pp. 10855–10860, 2006, doi: 10.1158/0008-5472.CAN-06-2564.

[246] S. J. Nelson, J. Kurhanewicz, D. B. Vigneron, P. E. Z. Z. Larson, A. L. Harzstark, M. Ferrone, M. van Criekinge, J. W. Chang, R. Bok, I. Park, G. Reed, L. Carvajal, E. J. Small, P. Munster, V. K. Weinberg, J. H. Ardenkjaer-Larsen, A. P. Chen, R. E. Hurd, L. I. Odegardstuen, F. J. Robb, J. Tropp, and J. A. Murray, “Metabolic imaging of patients with prostate cancer using hyperpolarized [1-13C]pyruvate,” *Sci. Transl. Med.*, vol. 5, no. 198, p. 198ra108, 2013, doi: 10.1126/scitranslmed.3006070.

[247] H. Gutte, A. E. Hansen, H. H. Johannesen, A. E. Clemmensen, J. H. Ardenkjær-Larsen, C. H. Nielsen, and A. Kjær, “The use of dynamic nuclear polarization (13C)-pyruvate MRS in cancer.,” *Am. J. Nucl. Med. Mol. Imaging*, vol. 5, no. 5, pp. 548–60, 2015, [Online]. Available: http://www.ncbi.nlm.nih.gov/pubmed/26550544%0Ah ttp://www.pubmedcentral.nih.gov/articlerender.fcgi?ar tid=PMC4620180.

[248] F. A. Gallagher, M. I. Kettunen, S. E. Day, D. E. Hu, J. H. Ardenkjær-Larsen, R. In 'T Zandt, P. R. Jensen, M. Karlsson, K. Golman, M. H. Lerche, and K. M. Brindle, “Magnetic resonance imaging of pH in vivo using hyperpolarized 13C-labelled bicarbonate,” *Nature*, vol. 453, no. 7197, pp. 940–943, 2008, doi: 10.1038/nature07017.

[249] J. H. Ardenkjaer-Larsen, C. Laustsen, S. Bowen, and R. Rizi, “Hyperpolarized H2O MR angiography,” *Magn. Reson. Med.*, vol. 71, no. 1, pp. 50–56, 2014, doi: 10.1002/mrm.25033.

[250] K. W. Lipsø, E. S. S. Hansen, R. S. Tougaard, C. Laustsen, and J. H. Ardenkjær-Larsen, “Dynamic coronary MR angiography in a pig model with hyperpolarized water,” *Magn. Reson. Med.*, vol. 80, no. 3, pp. 1165–1169, 2018, doi: 10.1002/mrm.27088.

[251] K. Wigh Lipsø, E. S. S. Hansen, R. S. Tougaard, C. Laustsen, and J. H. Ardenkjær-Larsen, “Renal MR angiography and perfusion in the pig using hyperpolarized water,” *Magn. Reson. Med.*, vol. 78, no. 3, pp. 1131–1135, 2017, doi: 10.1002/mrm.26478.