by Keyword: times

Kostas Mouloudakis, Sven Bodenstedt, Marc Azagra, Morgan W. Mitchell, Irene Marco-Rius, and Michael C. D. Tayler, (2023). Real-Time Polarimetry of Hyperpolarized 13C Nuclear Spins Using an Atomic Magnetometer Journal Of Physical Chemistry Letters 14, 1192-1197

We introduce a method for nondestructive quantification of nuclear spin polarization, of relevance to hyperpolarized spin tracers widely used in magnetic resonance from spectroscopy to in vivo imaging. In a bias field of around 30 nT we use a high-sensitivity miniaturized 87Rb-vapor magnetometer to measure the field generated by the sample, as it is driven by a windowed dynamical decoupling pulse sequence that both maximizes the nuclear spin lifetime and modulates the polarization for easy detection. We demonstrate the procedure applied to a 0.08 M hyperpolarized [1-13C]-pyruvate solution produced by dissolution dynamic nuclear polarization, measuring polarization repeatedly during natural decay at Earth's field. Application to real-time and continuous quality monitoring of hyperpolarized substances is discussed.

JTD Keywords: performance, polarization, Atomic magnetometers, Bias field, High sensitivity, Hyperpolarized, In-vivo imaging, Magnetic resonance, Magnetic-resonance, Magnetic-resonance,polarizatio, Magnetic-resonance,polarization,performanc, Magnetometers, Non destructive, Nuclear spins, Nuclear-spin polarization, Performance, Polarization, Rb vapors, Real- time, Spin dynamics, Spin polarization

Picazo-Frutos, R, Stern, Q, Blanchard, JW, Cala, O, Ceillier, M, Cousin, SF, Eills, J, Elliott, SJ, Jannin, S, Budker, D, (2023). Zero- to Ultralow-Field Nuclear Magnetic Resonance Enhanced with Dissolution Dynamic Nuclear Polarization Analytical Chemistry 95, 720-729

Zero- to ultralow-field nuclear magnetic resonance is a modality of magnetic resonance experiment which does not require strong superconducting magnets. Contrary to conventional high-field nuclear magnetic resonance, it has the advantage of allowing high-resolution detection of nuclear magnetism through metal as well as within heterogeneous media. To achieve high sensitivity, it is common to couple zero-field nuclear magnetic resonance with hyperpolarization techniques. To date, the most common technique is parahydrogen-induced polarization, which is only compatible with a small number of compounds. In this article, we establish dissolution dynamic nuclear polarization as a versatile method to enhance signals in zero-field nuclear magnetic resonance experiments on sample mixtures of [13C]sodium formate, [1-13C]glycine, and [2-13C]sodium acetate, and our technique is immediately extendable to a broad range of molecules with >1 s relaxation times. We find signal enhancements of up to 11,000 compared with thermal prepolarization in a 2 T permanent magnet. To increase the signal in future experiments, we investigate the relaxation effects of the TEMPOL radicals used for the hyperpolarization process at zero- and ultralow-fields.

JTD Keywords: injection, liquids, relaxation, times, Spectroscopy

Burgues, J., Valdez, L. F., Marco, S., (2019). High-bandwidth e-nose for rapid tracking of turbulent plumes ISOEN 2019 18th International Symposium on Olfaction and Electronic Nose , IEEE (Fukuoka, Japan) , 1-3

The low bandwidth of metal oxide semiconductor (MOX) sensors (<0.1 Hz) is a major hurdle to gas source localization (GSL) in turbulent environments where detection of intermittent odor patches is key. We present a fast-response miniaturized electronic nose (Fast-eNose) composed of four naked MOX sensors and a digital band-pass filter that can boost the bandwidth of the system close to 1 Hz. The device was attached to a fast photo-ionization detector (330 Hz) to quantify the response time during exposure to turbulent gas plumes. The results indicate that the digital filter can improve the response time by at least a factor of 4, bringing new possibilities to mobile robot olfaction.

JTD Keywords: CFD, Gas plume, Gas sensors, MOX, Response time, Signal processing