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Brzezicki A, Garbacz P. Differentiation and identification of enantiomers by nuclear magnetic resonance spectroscopy with support of quantum mechanical computations. Chirality 2024; 36:e23623. [PMID: 37827569 DOI: 10.1002/chir.23623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 08/28/2023] [Accepted: 09/19/2023] [Indexed: 10/14/2023]
Abstract
We report nuclear magnetic resonance studies of two chiral building blocks of solifenacin, phenyltetrahydroisoquinoline and quinuclidinol, in which chiral solvating agents, Mosher's acid, and Pirkle's alcohol were used for spectral discrimination between enantiomers of solifenacin constituents. Based on the constraints following from measurements of the nuclear Overhauser effect, structures of phenyltetrahydroisoquinoline and Pirkle's alcohol solvates were found. Next, shifts of nuclear magnetic resonance signals of phenyltetrahydroisoquinoline due to the application of Pirkle's alcohol were computed using density functional theory methods. The computed carbon-13 shifts reproduce those determined experimentally, allowing us to attribute the absolute configuration to phenyltetrahydroisoquinoline enantiomers without the need for the use of empirical rules.
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Affiliation(s)
- Artur Brzezicki
- Faculty of Chemistry, University of Warsaw, Warsaw, Poland
- Adamed Pharma S.A., Pieńków, Poland
| | - Piotr Garbacz
- Faculty of Chemistry, University of Warsaw, Warsaw, Poland
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2
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Polishchuk D, Gardeniers H. A compact permanent magnet for microflow NMR relaxometry. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2023; 347:107364. [PMID: 36599254 DOI: 10.1016/j.jmr.2022.107364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 12/21/2022] [Accepted: 12/22/2022] [Indexed: 06/17/2023]
Abstract
We design and demonstrate a compact, robust, and simple to assemble and tune permanent magnet suitable for NMR relaxometry measurements of microfluidic flows. Soft-magnetic stainless-steel plates, incorporated inside the magnet airgap, are key for obtaining substantially improved and tunable field homogeneity. The design is scalable for different NMR probe sizes with the region of suitable field homogeneity, less than 200 ppm, achievable in a capillary length of about 50 % of the total magnet length. The built physical prototype, having 3.5x3.5x8.0 cm3 in size and 5 mm high airgap, provides a field strength of 0.5 T and sufficient field homogeneity for NMR relaxometry measurements in capillaries up to 1.6 mm i.d. and 20 mm long. The magnet was used for test flow rate measurements in a wide range, from 0.001 ml/min to 20 ml/min.
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Affiliation(s)
- Dmytro Polishchuk
- Mesoscale Chemical Systems Group, University of Twente, 7500 AE Enschede, the Netherlands
| | - Han Gardeniers
- Mesoscale Chemical Systems Group, University of Twente, 7500 AE Enschede, the Netherlands.
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Silva P, Jouda M, Korvink J. Magnetostatic reciprocity for MR magnet design. MAGNETIC RESONANCE (GOTTINGEN, GERMANY) 2021; 2:607-617. [PMID: 37905211 PMCID: PMC10539805 DOI: 10.5194/mr-2-607-2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/20/2021] [Accepted: 06/29/2021] [Indexed: 11/02/2023]
Abstract
Electromagnetic reciprocity has long been a staple in magnetic resonance (MR) radio-frequency development, offering geometrical insights and a figure of merit for various resonator designs. In a similar manner, we use magnetostatic reciprocity to compute manufacturable solutions of complex magnet geometries, by establishing a quantitative metric for the placement and subsequent orientation of discrete pieces of permanent magnetic material. Based on magnetostatic theory and non-linear finite element modelling (FEM) simulations, it is shown how assembled permanent magnet setups perform in the embodiment of a variety of designs and how magnetostatic reciprocity is leveraged in the presence of difficulties associated with self-interactions, to fulfil various design objectives, including self-assembled micro-magnets, adjustable magnetic arrays, and an unbounded magnetic field intensity in a small volume, despite realistic saturation field strengths.
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Affiliation(s)
- Pedro Freire Silva
- Karlsruhe Institute of Technology (KIT), Institute of Microstructure Technology, 76131 Karlsruhe, Germany
| | - Mazin Jouda
- Karlsruhe Institute of Technology (KIT), Institute of Microstructure Technology, 76131 Karlsruhe, Germany
| | - Jan G. Korvink
- Karlsruhe Institute of Technology (KIT), Institute of Microstructure Technology, 76131 Karlsruhe, Germany
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Cooley CZ, Stockmann JP, Witzel T, LaPierre C, Mareyam A, Jia F, Zaitsev M, Wenhui Y, Zheng W, Stang P, Scott G, Adalsteinsson E, White JK, Wald LL. Design and implementation of a low-cost, tabletop MRI scanner for education and research prototyping. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2020; 310:106625. [PMID: 31765969 DOI: 10.1016/j.jmr.2019.106625] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 10/19/2019] [Accepted: 10/20/2019] [Indexed: 06/10/2023]
Abstract
While access to a laboratory MRI system is ideal for teaching MR physics as well as many aspects of signal processing, providing multiple MRI scanners can be prohibitively expensive for educational settings. To address this need, we developed a small, low-cost, open-interface tabletop MRI scanner for academic use. We constructed and tested 20 of these scanners for parallel use by teams of 2-3 students in a teaching laboratory. With simplification and down-scaling to a 1 cm FOV, fully-functional scanners were achieved within a budget of $10,000 USD each. The design was successful for teaching MR principles and basic signal processing skills and serves as an accessible testbed for more advanced MR research projects. Customizable GUIs, pulse sequences, and reconstruction code accessible to the students facilitated tailoring the scanner to the needs of laboratory exercise. The scanners have been used by >800 students in 6 different courses and all designs, schematics, sequences, GUIs, and reconstruction code is open-source.
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Affiliation(s)
- Clarissa Zimmerman Cooley
- A. A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, USA; Harvard Medical School, Boston, MA, USA.
| | - Jason P Stockmann
- A. A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, USA; Harvard Medical School, Boston, MA, USA
| | - Thomas Witzel
- A. A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, USA; Harvard Medical School, Boston, MA, USA
| | - Cris LaPierre
- A. A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, USA
| | - Azma Mareyam
- A. A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, USA
| | - Feng Jia
- Dept. of Radiology, Medical Physics, Medical Center University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Maxim Zaitsev
- Dept. of Radiology, Medical Physics, Medical Center University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Yang Wenhui
- Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing, China
| | - Wang Zheng
- Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing, China
| | - Pascal Stang
- Procyon Engineering, San Jose, CA, USA; Department of Electrical Engineering, Stanford University, Stanford, CA, USA
| | - Greig Scott
- Department of Electrical Engineering, Stanford University, Stanford, CA, USA
| | - Elfar Adalsteinsson
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA; Harvard-MIT Division of Health Sciences Technology, Cambridge, MA, USA
| | - Jacob K White
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Lawrence L Wald
- A. A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, USA; Harvard Medical School, Boston, MA, USA; Harvard-MIT Division of Health Sciences Technology, Cambridge, MA, USA
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Überrück T, Blümich B. Variable magnet arrays to passively shim compact permanent-yoke magnets. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2019; 298:77-84. [PMID: 30529894 DOI: 10.1016/j.jmr.2018.11.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Revised: 11/14/2018] [Accepted: 11/27/2018] [Indexed: 05/03/2023]
Abstract
C-shaped permanent magnets offer a compromise between sample accessability and field strength as well as homogeneity compared to single-sided devices or Halbach arrays. A new approach to passively shim C-shaped dipole magnets is presented. It relies on the magnet poles being constructed from a set of adjustable magnet elements. Two pole concepts are introduced, which allow the correction of the field profile and passively shim the magnet without the need of additional pole shoes or shim pieces.
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Affiliation(s)
- Till Überrück
- RWTH Aachen University, Institut für Technische und Makromolekulare Chemie, Worringerweg 2, 52074 Aachen, Germany
| | - Bernhard Blümich
- RWTH Aachen University, Institut für Technische und Makromolekulare Chemie, Worringerweg 2, 52074 Aachen, Germany.
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Hibino Y, Sugahara K, Muro Y, Tanaka H, Sato T, Kondo Y. Simple and low-cost tabletop NMR system for chemical-shift-resolution spectra measurements. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2018; 294:128-132. [PMID: 30036813 DOI: 10.1016/j.jmr.2018.07.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 06/08/2018] [Accepted: 07/06/2018] [Indexed: 05/03/2023]
Abstract
We have been working on developing a low-cost tabletop NMR system. We reported that a field homogeneity as high as 50 ppm was achieved with a simple NMR magnet by employing two facing ferrite magnets with iron disks in between (Chonlathep et al., 2017). In this paper, we report two improvements added to our previous system: (1) an FPGA based signal processing unit to improve the S/N ratio and (2) a simple shimming mechanism to improve the field homogeneity. We obtained as high as 1 ppm field homogeneity in the best case. The signals from hydrogen nuclear spins in a methyl and carboxy group in acetic acid were resolved in NMR spectra.
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Affiliation(s)
- Y Hibino
- Graduate School of Science and Engineering Research, Kindai University, 577-8502 Higashi-Osaka, Japan.
| | - K Sugahara
- Graduate School of Science and Engineering Research, Kindai University, 577-8502 Higashi-Osaka, Japan; Department of Electronics and Engineering, Kindai University, 577-8502 Higashi-Osaka, Japan.
| | - Y Muro
- THAMWAY Co., Ltd, 417-0001 Fuji, Japan
| | - H Tanaka
- THAMWAY Co., Ltd, 417-0001 Fuji, Japan
| | - T Sato
- THAMWAY Co., Ltd, 417-0001 Fuji, Japan
| | - Y Kondo
- Graduate School of Science and Engineering Research, Kindai University, 577-8502 Higashi-Osaka, Japan; Department of Physics, Kindai University, 577-8502 Higashi-Osaka, Japan.
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