Fluorescence lifetime imaging microscopy (FLIM) is a microscopic imaging technique to present an image of fluorophore lifetimes. It circumvents the problems of typical imaging methods such as intensity attenuation from depth since a lifetime is independent of the excitation intensity or fluorophore concentration. The lifetime is estimated from the time sequence of photon counts observed with signal-dependent noise, which has a Poisson distribution. Conventional methods usually estimate single or biexponential decay parameters. However, a lifetime component has a distribution or width, because the lifetime depends on macromolecular conformation or inhomogeneity. We present a novel algorithm based on a sparse representation which can estimate the distribution of lifetime. We verify the enhanced performance through simulations and experiments.
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http://dx.doi.org/10.1117/1.JBO.20.9.096003 | DOI Listing |
Sci Rep
December 2024
School of Physics Science and Engineering, Tongji University, Shanghai, 200092, People's Republic of China.
In this study, we investigate the application of support vector machines utilizing a radial basis function kernel for predicting nuclear α-decay half-lives. Our approach integrates a comprehensive set of physics-derived features, including characteristics derived from nuclear structure, to systematically evaluate their impact on predictive accuracy. In addition to traditional parameters such as proton and neutron numbers, as well as terms based on the liquid drop model (e.
View Article and Find Full Text PDFSci Total Environ
December 2024
Leibniz Universität Hannover, 30459 Hannover, Germany. Electronic address:
With the beginning of the COVID-19 pandemic, wastewater-based epidemiology (WBE), which according to Larsen et al. (2021), describes the science of linking pathogens and chemicals found in wastewater to population-level health, received an enormous boost worldwide. The basic procedure in WBE is to analyse pathogen concentrations and to relate these measurements to cases from clinical data.
View Article and Find Full Text PDFFront Med (Lausanne)
December 2024
Section of Neurobiology of the Eye, Ophthalmic Research Institute, University of Tübingen, Tübingen, Germany.
Purpose: Changes in choroidal thickness (ChT) are proposed to predict myopia development but evidence is mixed. We investigated time courses of choroidal responses, following different types of dynamic artificial stimulation in chicks with and without spectacle lenses, as well as changes in retinal dopamine metabolism and expression of candidate genes.
Methods: Chicks were kept in an arena surrounded by computer monitors presenting dynamic checkerboard fields of small, medium and large size.
Nanoscale Adv
December 2024
Institute of Science and Technology, TNU-University of Sciences Thai Nguyen Vietnam
This article studies the synthesis, as well as the structural, vibrational, and optical properties of Eu-doped ZnO quantum dots (QDs) and investigates the energy transfer mechanism from the ZnO host to Eu ions using Reisfeld's approximation. Eu-doped ZnO QDs at varying concentrations (0-7%) were successfully prepared using a wet chemical method. The successful doping of Eu ions into the ZnO host lattice, as well as the composition and valence states of the elements present in the sample, were confirmed through X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses.
View Article and Find Full Text PDFJ Chem Phys
December 2024
Graduate School of Science and Technology, Niigata University, 2-8050 Ikarashi, Nishi-ku, Niigata 950-2181, Japan.
For the clarification of dynamics of photogenerated carriers in practical organic solar cell devices, we have developed a methodology to simultaneously acquire reflection-mode transient optical absorption (ΔA) and transient electric current (Δi) signals. For a typical polythiophene:fullerene bulk heterojunction solar cell device, both the ΔA and Δi signals due to the photogenerated carriers are characterized by the power-law decays of ∝t-α, which are interpreted by detrapping-limited recombination at earlier times than ∼1 μs and trap-free diffusion/drift at later times. Furthermore, we have succeeded in observing switching of the power index α for ΔA signals as well as for Δi signals; the time at which switching occurs indicates the extraction of carriers by electrodes (transit times).
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