Article
Chemistry, Multidisciplinary
Huseyin Ovalioglu
Summary: The Overhauser dynamic nuclear polarization (DNP) method, utilizing the magnetic spin-spin interactivity between the F-19 nucleus of the solvent and the delocalized electrons on the MC800 asphaltene, was used to study asphaltene suspensions in difluorobenzene isomers at room temperature in a small magnetic field. The influence of sample age on the DNP parameters was investigated and analyzed.
Article
Spectroscopy
Muhammad Haroon, Wissam Iali, Abdulaziz A. Al-Saadi
Summary: Linuron, a commonly used organic herbicide, was studied using NMR and Raman spectroscopic techniques to investigate its conformational behavior and electronic aspects. The SERS technique with gold nanoparticles was implemented for concentration monitoring, successfully enhancing the Raman responses of four vibrational modes. Simulations predicted that the most pronounced binding of linuron with gold nanoclusters occurs at the benzene ring.
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
(2021)
Article
Chemistry, Physical
David Guarin, Diego Carnevale, Mathieu Baudin, Philippe Pelupessy, Daniel Abergel, Geoffrey Bodenhausen
Summary: In this study, the buildup of proton polarization due to dynamic nuclear polarization (DNP) was monitored by observing echoes instead of FIDs. It was found that under DNP conditions, the proton coherence lifetime was extended, leading to transient surges in spin echo amplitudes.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Chemistry, Physical
Yifan Quan, Yifu Ouyang, Michael Mardini, Ravi Shankar Palani, Daniel Banks, James Kempf, W. Tom Wenckebach, Robert G. G. Griffin
Summary: We propose a new mechanism for dynamic nuclear polarization called Resonant Mixing (RM). It arises from the evolution of the density matrix for a simple electron-nucleus coupled spin pair subject to weak microwave irradiation, similar to the solid effect. However, unlike the solid effect, RM is optimal when the microwave field is on-resonance and involves the mixing of states by the microwave field together with the electron-nuclear coupling. We argue that this mechanism is responsible for the observed dispersive-shaped DNP field profile for trityl samples near the electron paramagnetic resonance center.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Physical
Michele Kelley, Nicholas Bryden, Sebastian William Atalla, Rosa Tamara Branca
Summary: Ultra-low field nuclear magnetic resonance spectroscopy (NMR) and imaging (MRI) suffer from low signal-to-noise ratio due to small thermal polarization of nuclear spins. A technique called Spin Polarization Induced Nuclear Overhauser Effect (SPINOE) can transfer polarization from a pre-polarized spin system to a thermally polarized spin system, potentially overcoming this limitation. In this study, we demonstrate the direct detection of polarization transfer from highly polarized Xe-129 gas spins to H-1 spins in solution using SPINOE. We show that by bubbling hyperpolarized Xe-129 into the solution, H-1 polarization levels can be enhanced by up to 151-fold.
Article
Biochemistry & Molecular Biology
Nargiz B. B. Asanbaeva, Sergey A. A. Dobrynin, Denis A. A. Morozov, Nadia Haro-Mares, Torsten Gutmann, Gerd Buntkowsky, Elena G. G. Bagryanskaya
Summary: This paper reports on the DNP efficiency at a high magnetic field for two water-soluble biradicals resistant to reducing media. The radicals were obtained in the form of quaternary ammonium salts to achieve water solubility. The influence of hyperfine interaction and exchange interaction on the DNP effect was determined through EPR spectroscopy.
Article
Chemistry, Applied
Huseyin, Ovalioglu
Summary: Nuclear Magnetic Resonance and Overhauser effect type dynamic nuclear polarization (DNP) experiments were conducted to investigate asphaltene suspensions in fluorocarbons at a low magnetic field. The research focused on the influence of sample age on DNP parameters, revealing a smaller nuclear-electron coupling parameter and dominant dipolar part in intermolecular spin-spin interactions.
INDIAN JOURNAL OF CHEMICAL TECHNOLOGY
(2022)
Article
Chemistry, Multidisciplinary
Saiya Fujiwara, Naoto Matsumoto, Koki Nishimura, Nobuo Kimizuka, Kenichiro Tateishi, Tomohiro Uesaka, Nobuhiro Yanai
Summary: Utilizing the induced-fit-type structural transformation of a metal-organic framework (MOF), we demonstrate DNP of guest molecules at around room temperature, resulting in enhanced NMR signal.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Physical
Hideka Ando, Katsuaki Suzuki, Hironori Kaji, Takashi Kambe, Yuta Nishina, Chiyu Nakano, Kazuma Gotoh
Summary: Dynamic nuclear polarizing (DNP) technique in nuclear magnetic resonance (NMR) is a powerful tool for microanalysis, but its application to carbon materials like graphene oxide (GO) and amorphous carbon has been limited by their electroconductivity and microwave absorption. In this study, DNP-NMR was successfully applied to analyze surface functional groups on GO and sucrose-derived carbon, revealing enhanced peaks of 13C and the presence of previously undetectable functional groups. The dominant enhancement mechanism was found to be the cross effect, except for the CH3 groups on GO, which were mainly enhanced through Overhauser effect or solid effect.
Article
Biochemical Research Methods
Chen Yang, Kong Ooi Tan, Robert G. Griffin
Summary: DNPSOUP is an open-source numerical software program that models spin dynamics for dynamic nuclear polarization, utilizing the inhomogeneous master equation to treat the time evolution of the spin density operator under coherent Hamiltonians and stochastic relaxation effects. The program demonstrates its efficacy by simulating DNP field profiles on small spin systems, including various effects such as Zeeman field profiles and microwave field profiles. The software has the potential to aid in the design of optimized DNP polarizing agents and explore new pulsed DNP methods under conditions that are not currently experimentally accessible.
JOURNAL OF MAGNETIC RESONANCE
(2022)
Article
Biochemical Research Methods
Daniel J. Cheney, Christopher J. Wedge
Summary: The optical dynamic nuclear polarization (DNP) method is proposed as an alternative hyperpolarization method for solution-state NMR studies. Reducing the sample volume while maintaining constant optical density can significantly enhance the NMR signal, improving sensitivity of the technique.
JOURNAL OF MAGNETIC RESONANCE
(2022)
Article
Chemistry, Analytical
Xiaorong Gong, Shudong Chen, Shuang Zhang
Summary: The study utilizes the Overhauser magnetometer with deuterated N-15 TEMPONE radical to enhance sensitivity and successfully achieves sensitivity estimation in field environments. The direct measurement method is sensitive to electromagnetic interference while the synchronous measurement method shows a better ability to remove natural and artificial EMIs, providing a cost-effective sensitivity estimation method for instrument developers and users.
Article
Biochemistry & Molecular Biology
Fuminori Hyodo, Hinako Eto, Tatsuya Naganuma, Norikazu Koyasu, Abdelazim Elsayed Elhelaly, Yoshifumi Noda, Hiroki Kato, Masaharu Murata, Tomohiko Akahoshi, Makoto Hashizume, Hideo Utsumi, Masayuki Matsuo
Summary: In vivo molecular and metabolic imaging is an emerging field in biomedical research that aims to perform noninvasive detection of tissue metabolism in disease states and responses to therapeutic agents. Dynamic nuclear polarization magnetic resonance imaging (DNP-MRI) is a technique that enables the imaging of free radicals in living animals, providing a novel diagnostic tool for redox-related diseases and drug discovery. The future direction of this technique includes broad applications in studying other redox-related diseases and evaluating treatment response.
ANTIOXIDANTS & REDOX SIGNALING
(2022)
Article
Engineering, Mechanical
Jingtian Kang, Yanjun Tang
Summary: The study reveals that the inertial effect introduced by dynamic loading is significant at large pressure rates, and considering the surface effect, the cavity surface will expand, shrink, and oscillate before infinite cavity expansion occurs.
INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
(2021)
Article
Radiology, Nuclear Medicine & Medical Imaging
Dushyant Kumar, Blake Benyard, Narayan Datt Soni, Anshuman Swain, Neil Wilson, Ravinder Reddy
Summary: This study demonstrates the feasibility of brain lipid mapping using an easily implementable transient NOE (tNOE) approach at 7T.
MAGNETIC RESONANCE IN MEDICINE
(2023)