High magnetic fields significantly improve the resolution and sensitivity of nuclear magnetic resonance (NMR) spectroscopy measurements, which presents exciting research opportunities in areas of chemistry, biology, and material science. Powered magnets can provide much higher magnetic fields than persistent mode superconducting magnets but suffer from temporal magnetic field fluctuations due to power supply ripple and variations in cooling water temperature and flow rate which make powered magnets non-viable for high resolution NMR experiments. Previous work has demonstrated that a multi-rate sampled data cascade control system may be used to improve the resolution of NMR experiments in powered magnets. Despite these advances in reducing temporal magnetic field fluctuations, the field regulation design does not accommodate the use of pulsed field gradients, which are necessary in many NMR experiments. This work presents a control topology which accommodates the use of pulsed field gradient signals with the field regulation system. This control approach is verified using NMR measurements.
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http://dx.doi.org/10.1109/cdc45484.2021.9683312 | DOI Listing |
Radiology
January 2025
From the Institute of Diagnostic and Interventional Neuroradiology, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Ismaninger Strasse 22, Munich 81675, Germany.
Background Studies have explored the application of multimodal large language models (LLMs) in radiologic differential diagnosis. Yet, how different multimodal input combinations affect diagnostic performance is not well understood. Purpose To evaluate the impact of varying multimodal input elements on the accuracy of OpenAI's GPT-4 with vision (GPT-4V)-based brain MRI differential diagnosis.
View Article and Find Full Text PDFExp Physiol
January 2025
Centre for Healthy Ageing, Health Futures Institute, Murdoch University, Perth, Australia.
Blood flow restriction (BFR) combined with low work rate exercise can enhance muscular and cardiovascular fitness. However, whether neural mechanisms mediate these enhancements remains unknown. This study examined changes in corticospinal excitability and motor cortical inhibition following arm cycle ergometry with and without BFR.
View Article and Find Full Text PDFJ Fluoresc
January 2025
Department of Physics, Jnanabharathi, Bangalore University, Bengaluru, 560056, Karnataka, India.
In this report the photophysical property of newly synthesized fluorescein based derivative 2-(5-((2,4-dichlorophenyl)diazenyl)-6-hydroxy-3-oxo-3H-xanthen-9-yl)benzoic acid has studied by spectroscopic and theoretical that is by Density Functional Theory technique. The structural and functional group of the synthesized molecule was confirmed by nuclear magnetic resonance and fourier transform infrared spectroscopy technique, and from the result so far obtained has been confirmed that molecule has a stable structure and confirmed the presence the functional groups present in the sample. The optical properties of the molecule are studied using the spectroscopic technique and it has revealed the solute-solvent interaction behaviour of the molecule and it has been observed that the bathochromic shift was of about 5 nm, from the fluorescence measurement it has revealed that the emission has been observed at green region and from the power spectra it has been confirmed the same.
View Article and Find Full Text PDFProc IEEE Int Symp Biomed Imaging
May 2024
Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN, United States.
Parallel transmission (pTx) is an important technique for reducing transmit field inhomogeneities at ultrahigh-field (UHF) MRI. pTx typically involves solving an optimization problem for radiofrequency pulse design, with hard constraints on specific-absorption rate (SAR) and/or power, which may be time-consuming. In this work, we propose a novel approach towards incorporating hard constraints to physics-driven neural networks.
View Article and Find Full Text PDFIEEE J Solid-State Circuits
November 2024
Department of Electrical and Computer Engineering, Rice University, Houston TX, 77005, USA.
Miniature bioelectronic implants promise revolutionary therapies for cardiovascular and neurological disorders. Wireless power transfer (WPT) is a significant method for miniaturization, eliminating the need for bulky batteries in today's devices. Despite successful demonstrations of millimetric battery-free implants in animal models, the robustness and efficiency of WPT are known to degrade significantly under misalignment incurred by body movements, respiration, heart beating, and limited control of implant orientation during surgery.
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