We introduce and demonstrate a simple and highly sensitive method for characterizing single-photon detectors. This method is based on analyzing multi-order correlations among time-tagged detection events from a device under calibrated continuous-wave illumination. First- and second-order properties such as detection efficiency, dark count rate, afterpulse probability, dead time, and reset behavior are measured with high accuracy from a single data set, as well as higher-order properties such as higher-order afterpulse effects. While the technique is applicable to any type of click/no-click detector, we apply it to two different single-photon avalanche diodes, and we find that it reveals a heretofore unreported afterpulse effect due to detection events that occur during the device reset.
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http://dx.doi.org/10.1364/OE.25.020352 | DOI Listing |
Radiol Clin North Am
March 2025
Department of Medicine, UT Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-8558, USA; Department of Pediatrics, UT Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-8558, USA. Electronic address:
Pulmonary vascular diseases, particularly when accompanied by pulmonary hypertension, are complex disorders often requiring multimodal imaging for diagnosis and monitoring. Echocardiography is the primary screening tool for pulmonary hypertension, while cardiac MR imaging (CMR) is used for more detailed characterization and risk stratification in right ventricular failure. Chest computed tomography (CT) is used to detect vascular anomalies and parenchymal lung diseases.
View Article and Find Full Text PDFBioengineering (Basel)
December 2024
Department of Electronic Computational Equipment Design, National Technical University of Ukraine "Igor Sikorsky Kyiv Polytechnic Institute", 03056 Kyiv, Ukraine.
Parkinson's disease (PD) is a neurodegenerative disorder characterized by motor and neuropsychiatric symptoms resulting from the loss of dopamine-producing neurons in the substantia nigra pars compacta (SNc). Dopamine transporter scan (DATSCAN), based on single-photon emission computed tomography (SPECT), is commonly used to evaluate the loss of dopaminergic neurons in the striatum. This study aims to identify a biomarker from DATSCAN images and develop a machine learning (ML) algorithm for PD diagnosis.
View Article and Find Full Text PDFSe Pu
February 2025
CAS Key Laboratory of Separation Sciences for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
Chemical modifications are widely used in research fields such as quantitative proteomics and interaction analyses. Chemical-modification targets can be roughly divided into four categories, including those that integrate isotope labels for quantification purposes, probe the structures of proteins through covalent labeling or cross-linking, incorporate labels to improve the ionization or dissociation of characteristic peptides in complex mixtures, and affinity-enrich various poorly abundant protein translational modifications (PTMs). A chemical modification reaction needs to be simple and efficient for use in proteomics analysis, and should be performed without any complicated process for preparing the labeling reagent.
View Article and Find Full Text PDFNanophotonics
January 2025
Institute of Physics, Swiss Federal Institute of Technology Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
Sum-frequency generation (SFG) enables the coherent upconversion of electromagnetic signals and plays a significant role in mid-infrared vibrational spectroscopy for molecular analysis. Recent research indicates that plasmonic nanocavities, which confine light to extremely small volumes, can facilitate the detection of vibrational SFG signals from individual molecules by leveraging surface-enhanced Raman scattering combined with mid-infrared laser excitation. In this article, we compute the degree of second order coherence ( (0)) of the upconverted mid-infrared field under realistic parameters and accounting for the anharmonic potential that characterizes vibrational modes of individual molecules.
View Article and Find Full Text PDFAm J Nucl Med Mol Imaging
December 2024
Department of Radiology, University of Pennsylvania Philadelphia, PA 19104, USA.
This review assesses the primary neuroimaging techniques used to evaluate Parkinson's disease (PD) - a neurological condition characterized by gradual dopamine-producing nerve cell degeneration. The neuroimaging techniques explored include positron emission tomography (PET), single-photon emission computed tomography (SPECT), and magnetic resonance imaging (MRI). These modalities offer varying degrees of insights into PD pathophysiology, diagnostic accuracy, specificity by way of exclusion of other Parkinsonian syndromes, and monitoring of disease progression.
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