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Background: Recent advances in highly sensitive miniaturized optically pumped magnetometers (OPMs) have enabled the development of wearable magnetoencephalography (MEG) offering great flexibility in experimental setting. The OPM array for wearable MEG is typically attached to a flexible cap and exhibits a variable spatial layout across different subjects, which imposes challenges concerning the efficient positioning and labelling of OPMs.
New Method: A pair of reflective markers are affixed to each triaxial OPM sensor above its cable to determine its location and sensitive axes. A non-rigid registration of optically digitized marker locations with a pre-labelled template of marker locations is performed to map newly digitized markers to OPMs.
Results: The positioning and labelling of 66 OPM sensors could be completed within 35 s. Across ten experiments, all OPMs were accurately labelled, and the mean test-retest errors were 0.48 mm for sensor locations and 0.20 degree for sensitive axes. By combining six OPMs' positions with their respective recordings, magnetic dipoles inside a phantom were located with a mean error of 5.5 mm, and the best fitted dipole for MEG with auditory stimuli presented was located on a subject's primary auditory cortex.
Comparison With Existing Methods: The proposed method reduces the reliance on error-prone and laborious manual operations inherent in existing methods, therefore significantly improving the efficiency of OPM positioning and labelling on a flexible cap.
Conclusion: We developed a method for the precise and rapid positioning and labelling triaxial OPMs on a flexible cap, thereby facilitating the practical implementation of wearable OPM-MEG.
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http://dx.doi.org/10.1016/j.jneumeth.2023.110010 | DOI Listing |
J R Soc Interface
September 2025
Institute of Intelligent Systems and Robotics, Sorbonne Université, Paris, Île-de-France, France.
A number of techniques have been developed to measure the three-dimensional trajectories of protists, which require special experimental set-ups, such as a pair of orthogonal cameras. On the other hand, machine learning techniques have been used to estimate the vertical position of spherical particles from the defocus pattern, but they require the acquisition of a labelled dataset with finely spaced vertical positions. Here, we describe a simple way to make a dataset of images labelled with vertical position from a single 5 min movie, based on a tilted slide set-up.
View Article and Find Full Text PDFMethods
September 2025
Charles University, Faculty of Pharmacy in Hradec Kralove, Ak. Heyrovskeho 1203, Hradec Kralove 500 03, Czech Republic. Electronic address:
Chemically modified oligonucleotides (ONs) are essential tools in molecular biology, diagnostics, and therapeutics. Strain-promoted azide-alkyne cycloaddition (SPAAC) offers an efficient and bioorthogonal method for ON functionalization. While SPAAC reactions on solid-phase support provide distinct advantages, particularly for the incorporation of lipophilic labels, factors influencing their efficiency remain poorly characterized.
View Article and Find Full Text PDFSpectrochim Acta A Mol Biomol Spectrosc
September 2025
Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun 130122, China. Electronic address:
To achieve ultrasensitive and real-time detection of the H1N1 influenza virus, this study designed a nucleic acid-free fluorescent biosensor based on 3D spherical DNA nanostructure and CRISPR/Cas12a (3D-SDNC). The biosensor constructs a rigid 3D nano-framework via self-assembly of six oligonucleotide chains, with H1N1-specific nucleic acid aptamers and Cas12a activator strands strategically positioned at multi-spined vertices for precise spatial coupling between viral recognition and signal transduction. Upon aptamer-virus binding, the induced conformational change liberates the activator strand, thereby activating the trans-cleavage activity of the Cas12a/crRNA complex to efficiently cleave the HEX/BHQ1 double-labeled fluorescent probe and initiate cascade signal amplification.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
September 2025
Molecular Imaging Program at Stanford, Department of Radiology, School of Medicine, Stanford University, Palo Alto, CA 94304.
The biophysical properties of single cells are crucial for understanding cellular function and behavior in biology and medicine. However, precise manipulation of cells in 3-D microfluidic environments remains challenging, particularly for heterogeneous populations. Here, we present "Electro-LEV," a unique platform integrating electromagnetic and magnetic levitation principles for dynamic 3-D control of cell position during separation.
View Article and Find Full Text PDFJ Vis Exp
August 2025
Department of Nutritional Sciences, University of Wisconsin-Madison;
The retinol isotope dilution (RID) test is the most sensitive method to assess vitamin A status by estimating total liver reserves, considered the reference standard. For gas chromatography-combustion-isotope ratio mass spectrometry detection, C is added to the retinol moiety. The synthetic procedure for C-retinyl acetate begins with the naturally occurring β-ionone.
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