Ultrasonic diffraction tomography offers a way to achieve high-resolution imaging of the wave-speed map, and hence, has strong potential applications in medical diagnosis and nondestructive evaluation. Ideal images can be obtained with a complete array of sensors surrounding the scatterer, provided that the measurement data are fully sampled in space, obeying the Nyquist criterion. Spatial undersampling causes the image to be distorted and introduce unwanted circular artifacts. In this paper, we propose an iteration approach using virtual transducers to achieve high-resolution tomographic imaging with undersampled measurements. At each iteration stage, the extent constraint estimated from the shape of the object of interest is applied on the image space to obtain a regularized image, based on which the ultrasonic measurement data at virtual transducers are calculated using a forward model. The full data set composed of original and virtual measurements is then used for tomography in the next stage. A final image with sufficiently high resolution is obtained only after a few iterations. The new imaging method yields improvements in the robustness and accuracy of ultrasonic tomography with undersampled data. We present numerical results using complicated wave-speed maps from realistic corrosion profiles. In addition, an experiment using guided ultrasonic waves is performed to further evaluate the imaging method.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1109/TUFFC.2018.2828644 | DOI Listing |
Nat Commun
January 2025
Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark.
Tetrahydrocannabinol (THC) is the principal psychoactive compound derived from the cannabis plant Cannabis sativa and approved for emetic conditions, appetite stimulation and sleep apnea relief. THC's psychoactive actions are mediated primarily by the cannabinoid receptor CB. Here, we determine the cryo-EM structure of HU210, a THC analog and widely used tool compound, bound to CB and its primary transducer, G.
View Article and Find Full Text PDFSensors (Basel)
December 2024
Fundación Centro Tecnológico CTC-Scientific and Technological Park of Cantabria (PCTCAN), Street Isabel Torres Nº 1, 39011 Santander, Spain.
This study presents the design and validation of a numerical method based on an AI-driven ROM framework for implementing stress virtual sensing. By leveraging Reduced-Order Models (ROMs), the research aims to develop a virtual stress transducer capable of the real-time monitoring of mechanical stresses in mechanical components previously analyzed with high-resolution FEM simulations under a wide range of multiple load scenarios. The ROM is constructed through neural networks trained on Finite Element Method (FEM) outputs from multiple scenarios, resulting in a simplified yet highly accurate model that can be easily implemented digitally.
View Article and Find Full Text PDFMol Divers
December 2024
School of Basic Medical Sciences, Ningxia Medical University, 1160 Shengli Road, Yinchuan, 750004, Ningxia, China.
The development of phosphorylation-suppressing inhibitors targeting Signal Transducer and Activator of Transcription 3 (STAT3) represents a promising therapeutic strategy for non-small cell lung cancer (NSCLC). In this study, a generative model was developed using transfer learning and virtual screening, leveraging a comprehensive dataset of STAT3 inhibitors to explore the chemical space for novel candidates. This approach yielded a chemically diverse library of compounds, which were prioritized through molecular docking and molecular dynamics (MD) simulations.
View Article and Find Full Text PDFG protein-coupled receptors (GPCRs) remain a focal point of research due to their critical roles in cell signaling and their prominence as drug targets. However, directly linking drug efficacy to receptor-mediated activation of specific intracellular transducers and the resulting physiological outcomes remains challenging. It is unclear whether the enhanced therapeutic window of certain drugs - defined as the dose range that provides effective therapy with minimal side effects - stems from their low intrinsic efficacy across all signaling pathways or ligand bias, wherein specific transducer subtypes are preferentially activated in a given cellular system compared to a reference ligand.
View Article and Find Full Text PDFACS Sens
December 2024
Tor Vergata University of Rome, Department of Chemical Sciences and Technologies, Rome 00133, Italy.
A consistent part of gas sensor research activities aims to improve sensing performances by synthesizing new sensing materials, improving the selection of elements in arrays, and optimizing the feature extraction and classification algorithms. This paper combines most of these aspects to confer selectivity to a low-selectivity sensor by using feature extraction algorithms applied to the sensor response kinetics. Several algorithms were employed to represent the kinetic behavior of the sensor response during the adsorption and desorption phases.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!