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Patrick M. TomHon Dr. Suyong Han Dr. Sören Lehmkuhl Prof. Stephan Appelt Prof. Eduard Y. Chekmenev Prof. Milad Abolhasani Prof. Thomas Theis 《Chemphyschem》2021,22(24):2526-2534
We introduce a Spin Transfer Automated Reactor (STAR) that produces continuous parahydrogen induced polarization (PHIP), which is stable for hours to days. We use the PHIP variant called signal amplification by reversible exchange (SABRE), which is particularly well suited to produce continuous hyperpolarization. The STAR is operated in conjunction with benchtop (1.1 T) and high field (9.4 T) NMR magnets, highlighting the versatility of this system to operate with any NMR or MRI system. The STAR uses semipermeable membranes to efficiently deliver parahydrogen into solutions at nano to milli Tesla fields, which enables 1H, 13C, and 15N hyperpolarization on a large range of substrates including drugs and metabolites. The unique features of the STAR are leveraged for important applications, including continuous hyperpolarization of metabolites, desirable for examining steady-state metabolism in vivo, as well as for continuous RASER signals suitable for the investigation of new physics. 相似文献
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Baptiste Joalland Nuwandi M. Ariyasingha Sren Lehmkuhl Thomas Theis Stephan Appelt Eduard Y. Chekmenev 《Angewandte Chemie (International ed. in English)》2020,59(22):8654-8660
Radio amplification by stimulated emission of radiation (RASER) was recently discovered in a low‐field NMR spectrometer incorporating a highly specialized radio‐frequency resonator, where a high degree of proton‐spin polarization was achieved by reversible parahydrogen exchange. RASER activity, which results from the coherent coupling between the nuclear spins and the inductive detector, can overcome the limits of frequency resolution in NMR. Here we show that this phenomenon is not limited to low magnetic fields or the use of resonators with high‐quality factors. We use a commercial bench‐top 1.4 T NMR spectrometer in conjunction with pairwise parahydrogen addition producing proton‐hyperpolarized molecules in the Earth's magnetic field (ALTADENA condition) or in a high magnetic field (PASADENA condition) to induce RASER without any radio‐frequency excitation pulses. The results demonstrate that RASER activity can be observed on virtually any NMR spectrometer and measures most of the important NMR parameters with high precision. 相似文献
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Dr. Baptiste Joalland Nuwandi M. Ariyasingha Dr. Sören Lehmkuhl Prof. Thomas Theis Prof. Stephan Appelt Prof. Eduard Y. Chekmenev 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(22):8732-8738
Radio amplification by stimulated emission of radiation (RASER) was recently discovered in a low-field NMR spectrometer incorporating a highly specialized radio-frequency resonator, where a high degree of proton-spin polarization was achieved by reversible parahydrogen exchange. RASER activity, which results from the coherent coupling between the nuclear spins and the inductive detector, can overcome the limits of frequency resolution in NMR. Here we show that this phenomenon is not limited to low magnetic fields or the use of resonators with high-quality factors. We use a commercial bench-top 1.4 T NMR spectrometer in conjunction with pairwise parahydrogen addition producing proton-hyperpolarized molecules in the Earth's magnetic field (ALTADENA condition) or in a high magnetic field (PASADENA condition) to induce RASER without any radio-frequency excitation pulses. The results demonstrate that RASER activity can be observed on virtually any NMR spectrometer and measures most of the important NMR parameters with high precision. 相似文献
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Dr. Andrey N. Pravdivtsev Prof. Dr. Frank D. Sönnichsen Prof. Dr. Jan-Bernd Hövener 《Chemphyschem》2020,21(7):667-672
Nuclear Magnetic Resonance (NMR) is an intriguing quantum-mechanical effect that is used for routine medical diagnostics and chemical analysis alike. Numerous advancements have contributed to the success of the technique, including hyperpolarized contrast agents that enable real-time imaging of metabolism in vivo. Herein, we report the finding of an NMR radio amplification by stimulated emission of radiation (RASER), which continuously emits 1H NMR signal for more than 10 min. Using parahydrogen induced hyperpolarization (PHIP) with 50 % para-hydrogen, we demonstrated the effect at 600 MHz but expect that it is functional across a wide range of frequencies, e.g. 101–103 MHz. PHIP-RASER occurs spontaneously or can be triggered with a standard NMR excitation. Full chemical shift resolution was maintained, and a linewidth of 0.6 ppb was achieved. The effect was reproduced by simulations using a weakly coupled, two spin- system. All devices used were standard issue, such that the effect can be reproduced by any NMR lab worldwide with access to liquid nitrogen for producing parahydrogen. 相似文献
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Jing Yang Peng Wang Prof. Dr. Jan G. Korvink Prof. Dr. Jürgen J. Brandner Dr. Sören Lehmkuhl 《Chemphyschem》2023,24(14):e202300204
A RASER (Radio Amplification by Stimulated Emission of Radiation) facilitates the study of nonlinear phenomena, as well as the determination of NMR parameters with high precision. To achieve maximum sensitivity in the desired operating mode, it is crucial to control the RASER over long periods of time. So far, this was only possible at ultra-low magnetic fields. Here, we introduce a way to control the operating regime of a RASER at a magnetic field of 1.45 T. We employ a continuous-flow RASER, pumped by PHIP (ParaHydrogen Induced Polarization). The hydrogenation of vinyl acetate (VA) with parahydrogen provides the required negative polarization on the methyl group of the product ethyl acetate (EA). The protons within the methyl group, separated by a 7 Hz J-coupling, are RASER active. This system demonstrates five RASER phenomena: inequivalent and equivalent amplitudes in the “normal NMR mode”, period doublings, frequency combs, and chaos. The experiments match with simulations based on a theoretical model of two nonlinear-coupled RASER modes. We predict the RASER regime at set conditions and visualize the prediction in a bifurcation diagram. 相似文献
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Christopher Nelson Dr. Andreas B. Schmidt Isaiah Adelabu Shiraz Nantogma Prof. Dr. Valerij G. Kiselev Abubakar Abdurraheem Henri de Maissin Dr. Sören Lehmkuhl Prof. Dr. Stephan Appelt Prof. Thomas Theis Prof. Eduard Y. Chekmenev 《Angewandte Chemie (International ed. in English)》2023,62(5):e202218484
The feasibility of Carbon-13 Radiofrequency (RF) Amplification by Stimulated Emission of Radiation (C-13 RASER) is demonstrated on a bolus of liquid hyperpolarized ethyl [1-13C]acetate. Hyperpolarized ethyl [1-13C]acetate was prepared via pairwise addition of parahydrogen to vinyl [1-13C]acetate and polarization transfer from nascent parahydrogen-derived protons to the carbon-13 nucleus via magnetic field cycling yielding C-13 nuclear spin polarization of approximately 6 %. RASER signals were detected from samples with concentration ranging from 0.12 to 1 M concentration using a non-cryogenic 1.4T NMR spectrometer equipped with a radio-frequency detection coil with a quality factor (Q) of 32 without any modifications. C-13 RASER signals were observed for several minutes on a single bolus of hyperpolarized substrate to achieve 21 mHz NMR linewidths. The feasibility of creating long-lasting C-13 RASER on biomolecular carriers opens a wide range of new opportunities for the rapidly expanding field of C-13 magnetic resonance hyperpolarization. 相似文献
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