The NMR hyperpolarization of uniformly 15 N-labeled [ 15 N 3 ]metronidazole is demonstrated by using SABRE-SHEATH. In this antibiotic, the 15 NO 2 group is hyperpolarized throughs pin relays createdb y 15 Ns pins in [ 15 N 3 ]metronidazole, and the polarization is transferred from parahydrogen-derivedh ydrides over six chemical bonds. In less than am inute of parahydrogen bubbling at approximately 0.4 mT, ah igh level of nuclear spin polarization( P 15N ) of around 16 %i sa chieved on all three 15 Ns ites. This prod-uct of 15 Np olarization andc oncentration of 15 Ns pins is arounds ix-fold bettert han any previous value determined for 15 NS ABRE-derived hyperpolarization. At 1.4 T, the hyperpolarized state persists fort ens of minutes (relaxation time, T 1 %10 min). An ovel synthesis of uniformly 15 N-enriched metronidazole is reported with ay ield of 15 %. This approachc an potentially be used for synthesis of aw ide variety of in vivom etabolic probesw ith potentialu ses ranging from hypoxiasensing to theranostic imaging.[a] Prof.

Chekmenev). Co-authored >30 peer-reviewed articles covering advanced MR detection hardware and utilizing hyperpolarization techniques to enable MR contrast agents for in vivo molecular imaging for improved human health.

The presence of 14N nucleus in the scalar coupling network results in a 3-fold decrease of 15N T1 and polarization values for all 15N sites in 15N2-metronidazole versus15N3-metronidazole in SABRE hyperpolarization in microtesla fields.

We present spin-exchange optical pumping (SEOP) using a third-generation (GEN-3) automated batch-mode clinicalscale 129 Xe hyperpolarizer utilizing continuous high-power (∼170 W) pump laser irradiation and a novel aluminum jacket design for rapid temperature ramping of xenon-rich gas mixtures (up to 2 atm partial pressure). The aluminum jacket design is capable of heating SEOP cells from ambient temperature (typically 25°C) to 70°C (temperature of the SEOP process) in 4 min, and perform cooling of the cell to the temperature at which the hyperpolarized gas mixture can be released from the hyperpolarizer (with negligible amounts of Rb metal leaving the cell) in approximately 4 min, substantially faster (by a factor of 6) than previous hyperpolarizer designs relying on air heat exchange. These reductions in temperature cycling time will likely be highly advantageous for the overall increase of production rates of batch-mode (i.e., stopped-flow) 129 Xe hyperpolarizers, which is particularly beneficial for clinical applications. The additional advantage of the presented design is significantly improved thermal management of the SEOP cell. Accompanying the heating jacket design and performance, we also evaluate the repeatability of SEOP experiments conducted using this new architecture, and present typically achievable hyperpolarization levels exceeding 40% at exponential build-up rates on the order of 0.1 min −1 .

Prof. Eduard Y. Chekmenev received his PhD in Physical Chemistry (supervisor Prof. Richard J. Wittebort) in 2003 at the University of Louisville, KY (USA). He conducted postdoctoral research at the National High Magnetic Field Laboratory in Tallahassee, FL (with Prof. Timothy Cross), Caltech (Prof. Daniel P. Weitekamp) and HMRI in Pasadena, CA (USA) (with Dr.B rian D. Ross). In 2009, Dr.C hekmenev started his hyperpolarization program at Vanderbilt University (Nashville, TN) and he was tenured in 2015. In 2018, he moved to Wayne State University (Detroit, MI) to continue his research on MR hyperpolarization.Figure 1. Thermal equilibrium polarizationp roduces asmall excess of spins in one state. When the sample undergoes hyperpolarization, alarge excess of spins exists in one state producingaconsiderably stronger signal since more spins contribute.

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We present an automated parahydrogen generator (Para-Sun) for clinical-scale applications in parahydrogen-induced polarization (PHIP) and signal amplification by reversible exchange (SABRE) at high pressures. The device employs a vacuum-pumped, Sunpower cryo-cooler (typically employed for cooling cellular network antennas) to achieve up to ∼87% parahydrogen enrichment at a temperature as low as ∼40 K and a maximum outlet pressure of ∼490 PSI. The device reaches the target temperature set-point in under 1 h. It employs a FeO(OH) catalyst for the ortho-to para-state conversion. A mass-flow controller (MFC) facilitates the controlled flow of H 2 gas at a rate of 150 standard cubic centimeters per minute (sccm). This design bridges the gap between rudimentary 50% enrichment liquid-N 2 baths and far costlier, near-unity-enrichment configurations employing high-H 2 throughputs and <25 K temperatures. The design presented here should be of interest for those pursuing a wide variety of PHIP applications, including those involving the production of inhalable or injectable hyperpolarized contrast agents for biomedical imaging.