About

Wendy Warren is an Associate Professor of History and the Associate Director of the Shelby Cullom Davis Center at Princeton University. She specializes in the history of colonial North America and the early modern Atlantic World, with particular interests in power struggles between would-be rulers and the unruly. Her research emphasizes the importance of slavery in early American history, including in New England during the seventeenth century, challenging traditional narratives that marginalize slavery's role in that region and period. Her first book, 'New England Bound: Slavery and Colonization in Early America' (2016), explores these themes and has received significant recognition, including the Organization of American Historians' 2017 Merle Curti Social History Prize, and was a finalist for the 2017 Pulitzer Prize, the Berkshire Conference Book Prize, and the Harriet Tubman Prize. Warren's scholarly work has been published in prominent venues such as the Journal of American History, the William and Mary Quarterly, and Slavery and Abolition. Currently, she is working on a project about prisons in the seventeenth and eighteenth centuries, focusing on incarceration's role in the process of European colonization in North America. Her teaching and research interests include colonial and revolutionary North America, the Atlantic world, comparative slavery, carceral studies, and gender and sexuality studies.

Research topics

• Optics
• Materials science
• Physics
• Chemistry
• Nuclear magnetic resonance

Selected publications

• Evaluating metastatic melanoma with optical pump-probe microscopy (Conference Presentation)

  2025-03-20

  articleSenior author
  PublisherDOI

• Investigation of 15N-SABRE hyperpolarization at high pressures and in supercritical fluids

  Journal of Magnetic Resonance · 2025-04-26

  articleOpen accessSenior authorCorresponding

  Signal Amplification By Reversible Exchange (SABRE) is a parahydrogen-based hyperpolarization technique that can generate orders-of-magnitude larger signals than thermal spin polarization within a minute. However, this method is limited by the availability of parahydrogen to the solution. Previous work demonstrated SABRE-derived 1 H hyperpolarization at pressures up to 200 bar and using liquid carbon dioxide as a solvent. Here, we extend this work to demonstrate heteronuclear ( 15 N) SABRE hyperpolarization using conventional solvents with hydrogen pressures up to 400 bar as well as the possibility of using supercritical CO 2 as the solvent. We demonstrate that in both modes, 15 N hyperpolarization comparable to SABRE-SHEATH may be achieved, providing a route for future optimization efforts as well as scale-up. We also present first steps towards exploring SABRE hyperpolarization of 129 Xe.

  PublisherDOI

• Exchange-selective excitation pulses for dynamic magnetic resonance

  Science Advances · 2025-02-19

  articleOpen accessSenior authorCorresponding

  Coherent evolution is punctuated by dynamical processes such as chemical exchange, conformational transformation, or site hopping in many important problems ranging from biomolecular function to ion trap quantum computation. One well-explored example is nuclear magnetic resonance (NMR) spectroscopy, where experimental development is grounded in decades-old theory, but structural dynamics are not easily integrated into this picture. Here, we introduce an approach that selectively excites NMR resonances that undergo chemical exchange while suppressing the signal arising from nondynamic components of the system. We show that for exchange rates spanning more than four orders of magnitude, one can still selectively excite spins undergoing exchange while suppressing static resonances. Generalizing this approach, to selectively excite (or selectively preserve) only members of an ensemble that have undergone exchange or rearrangement, has the potential to improve the analytical power of many spectroscopic techniques.

  PublisherDOI

• Angle-resolved Measurements Reveal the Origin of Signal Anisotropy in Pump-probe Microscopy

  bioRxiv (Cold Spring Harbor Laboratory) · 2025-12-27

  articleOpen accessSenior author

  Nonlinear optical microscopy modalities have become widely used in applications ranging from material characterization to tissue diagnosis. In complex systems, multiple mechanisms often contribute to the signal; for example, two-color pump-probe microscopy provides rich molecular signatures of the samples based on several nonlinear processes. Here we uncover a surprising complication, that in many cases the detection direction drastically alters the signal components and the overall amplitude. To understand the origin of this signal anisotropy, we first calculate and measure a simple case, the pump-probe signal of gold nanoshells at various detection angles, attributing the effect to scattering changes due to the sample refractive index change; we then extend this analysis, showing a striking directional dependence arising from distinct scattering profiles of two dominant nonlinear processes. These results demonstrate that comparing epi (backward) and transmission (forward) signals provides additional information, enabling cleaner separation of nonlinear contributions in pump-probe measurements.

  PublisherDOI

• Non-resonant SABRE provides a new and versatile hyperpolarization approach for magnetic resonance

  ArXiv.org · 2025-11-06

  preprintOpen accessSenior author

  Hyperpolarization approaches in magnetic resonance overcome the sensitivity limitations imposed by thermal magnetization and play an important role in a very wide range of modern applications. One of the newer strategies, variants of what is generically called SABRE, uses para-hydrogen to form hydrides on transition metal catalysts, followed by reversible exchange to polarize target molecules in solution, and has produced large signal enhancements (approx. 10^4) on hundreds of different molecules, cheaply and rapidly. Most commonly, the sample is kept in a constant field, matched to make the hydride scalar coupling comparable to the frequency difference between hydride protons and target protons (approx. 6.5 mT) or hydride protons and target heteronuclei (approx. 0.5 μT). Here we demonstrate a different strategy, applicable to a wide range of target molecules, that produces field-independent spin order in the target molecules that is efficiently converted to magnetization. The observed signal is even independent of field direction, hence significant polarization can be achieved in a sample on a lab bench with no field control at all. We show this signal arises from creation of two-spin order in the target molecules, and discuss multiple ways this strategy should expand SABRE generality and efficiency. We also show that, in many cases, the standard assumption in low-field SABRE of a starting state with only singlet polarization leads to incorrect results.

  PublisherOA PDFDOI

• Alexander Pines and the end of an era

  Science Advances · 2025-02-12

  reviewOpen access1st authorCorresponding
  PublisherDOI

• Efficient 15N hyperpolarization of [15N3]metronidazole antibiotic via spin-relayed pulsed SABRE-SHEATH

  Journal of Magnetic Resonance Open · 2025-07-24 · 3 citations

  articleOpen access

  • 15N-labeled metronidazole antibiotic was hyperpolarized via pulsed SABRE-SHEATH method; • 15N polarization of up to 18% was achieved for 20 mM drug in 80 seconds; • Feasibility of spin-relayed polarization transfer between three 15N sites was demonstrated in pulsed SABRE-SHEATH; • 15N relaxation dynamics is reported in a wide range of magnetic fields. Signal Amplification by Reversible Exchange in SHield Enables Alignment Transfer to Heteronuclei (SABRE-SHEATH) is an NMR hyperpolarization technique that relies of the simultaneous exchange of parahydrogen and a to-be-hyperpolarized molecule on the metal center of a polarization-transfer catalyst in a microtesla magnetic field. Until recently, this method has been understood to perform hyperpolarization by establishing level anti-crossings between the nuclear spins of the parahydrogen derived hydrides (acting as a source of hyperpolarization) and those of the substrate. Recently, the application of highly non-intuitive pulse sequences (comprising pulses of microtesla DC fields) was predicted to hyperpolarize nuclear spins more efficiently than the canonical (static-field) SABRE-SHEATH approach. Here we show that by employing a basic “on-off” pulse sequence of rectangular microtesla pulses, it is possible to improve the hyperpolarization efficiency for SABRE-SHEATH of [ 15 N 3 ]metronidazole, an FDA-approved antibiotic (in non-enriched and non-hyperpolarized form) and potential hypoxia sensing molecule. Specifically, we demonstrate that 15 N polarization of 18.5% can be obtained in 80 s of parahydrogen bubbling parahydrogen through a solution containing 20 mM [ 15 N 3 ]metronidazole. In practice, (1.32±0.14)-fold improvements in P 15N was obtained with the pulsed method described here compared to static field technique variant. These results show that pulsed SABRE-SHEATH was successfully applied to 15 N-labeled biologically relevant molecule. Moreover, we also demonstrate that although the pulsed SABRE-SHEATH sequence was designed for polarization transfer from parahydrogen derived hydrides to the metronidazole’s 15 N catalyst-binding site, all three 15 N sites of [ 15 N 3 ]metronidazole attained the hyperpolarized state. This spin-relayed polarization transfer becomes possible due to the 15 N relay network established by their spin-spin J -couplings. The feasibility of the spin-relayed polarization transfer is demonstrated here for the first time for pulsed SABRE-SHEATH (as opposed to the static-field SABRE-SHEATH reported previously) and it paves the way to broad applicability of the technique.

  PublisherDOI

• Noninvasive identification of carbon-based black pigments with pump-probe microscopy

  Science Advances · 2024-12-11 · 3 citations

  articleOpen access

  Carbon-based black pigments, a widely used class of pigments, are difficult to differentiate with the noninvasive techniques currently used in cultural heritage science. We use pump-probe microscopy, coupled with a support vector machine, to distinguish common carbon-based black pigments as pure pigments, as two-component black pigment mixtures, and as a mixture of a black and a colorful pigment. This work showcases the potential of pump-probe microscopy to spatially differentiate carbon-based black pigments, which would have interesting applications to works of art.

  PublisherDOI

• Noninvasive identification of carbon-based black pigments with pump-probe microscopy

  arXiv (Cornell University) · 2024-03-13 · 1 citations

  preprintOpen access

  Carbon-based black pigments, a widely used class of pigments, are difficult to differentiate with the noninvasive techniques currently used in cultural heritage science. We utilize pump-probe microscopy to distinguish four common carbon-based black pigments as pure pigments, as two-component black pigment mixtures, and as a mixture of a black and a colorful pigment. This work also demonstrates that even nominally homogeneous pigments present remarkable, and useful, heterogeneity in pump-probe microscopy.

  PublisherOA PDFDOI

• Molecular NMR shieldings, J-couplings, and magnetizabilities from numeric atom-centered orbital based density-functional calculations

  UNC Libraries · 2024-11-20

  articleOpen access

  This paper reports and benchmarks a new implementation of nuclear magnetic resonance shieldings, magnetizabilities, and J-couplings for molecules within semilocal density functional theory, based on numeric atom-centered orbital (NAO) basis sets. NAO basis sets are attractive for the calculation of these nuclear magnetic resonance (NMR) parameters because NAOs provide accurate atomic orbital representations especially near the nucleus, enabling high-quality results at modest computational cost. Moreover, NAOs are readily adaptable for linear scaling methods, enabling efficient calculations of large systems. The paper has five main parts: (1) It reviews the formalism of density functional calculations of NMR parameters in one comprehensive text to make the mathematical background available in a self-contained way. (2) The paper quantifies the attainable precision of NAO basis sets for shieldings in comparison to specialized Gaussian basis sets, showing similar performance for similar basis set size. (3) The paper quantifies the precision of calculated magnetizabilities, where the NAO basis sets appear to outperform several established Gaussian basis sets of similar size. (4) The paper quantifies the precision of computed J-couplings, for which a group of customized NAO basis sets achieves precision of ∼Hz for smaller basis set sizes than some established Gaussian basis sets. (5) The paper demonstrates that the implementation is applicable to systems beyond 1000 atoms in size.

  PublisherDOI

Recent grants

• NIH Grant R21RR019770

  NIH · $452k · 2006

• Improving Understanding, Utility and Generality of Hyperpolarized, Long-lived Spin States in Magnetic Resonance

  NSF · $650k · 2017–2021

• NIH Grant RC1CA145105

  NIH · $998k · 2012

• Making Clinical Scale Hyperpolarization Simple, Fast, and Cheap

  NIH · $408k · 2018–2021

• NIH Grant P41RR005959

  NIH · $4.6M · 2013

Frequent coauthors

• Martin C. Fischer

  100 shared

• Jesse W. Wilson

  74 shared

• Thomas Theis

  North Carolina State University

  69 shared

• Francisco E. Robles

  The Wallace H. Coulter Department of Biomedical Engineering

  67 shared

• Eduard Y. Chekmenev

  The Barbara Ann Karmanos Cancer Institute

  55 shared

• Simone Degan

  Duke University

  45 shared

• Thomas E. Matthews

  40 shared

• Sangdoo Ahn

  39 shared

Labs

• Wendy Warren's LabPI

Awards & honors

• Organization of American Historians' 2017 Merle Curti Social…
• Finalist for the 2017 Pulitzer Prize
• Finalist for the 2017 Berkshire Conference Book Prize
• Finalist for the 2017 Harriet Tubman Prize