Significance: Optical coherence tomography (OCT) is an interferometric imaging modality, which provides tomographic information on the microscopic scale. Furthermore, OCT signal analysis facilitates quantification of tissue optical properties (e.g., the attenuation coefficient), which provides information regarding the structure and organization of tissue. However, a rigorous and standardized measure of the precision of the OCT-derived optical properties, to date, is missing.
Aim: We present a robust theoretical framework, which provides the Cramér -Rao lower bound σμOCT for the precision of OCT-derived optical attenuation coefficients.
Approach: Using a maximum likelihood approach and Fisher information, we derive an analytical solution for σμOCT when the position and depth of focus are known. We validate this solution, using simulated OCT signals, for which attenuation coefficients are extracted using a least-squares fitting procedure.
Results: Our analytical solution is in perfect agreement with simulated data without shot noise. When shot noise is present, we show that the analytical solution still holds for signal-to-noise ratios (SNRs) in the fitting window being above 20 dB. For other cases (SNR<20 dB, focus position not precisely known), we show that the numerical calculation of the precision agrees with the σμOCT derived from simulated signals.
Conclusions: Our analytical solution provides a fast, rigorous, and easy-to-use measure for OCT-derived attenuation coefficients for signals above 20 dB. The effect of uncertainties in the focal point position on the precision in the attenuation coefficient, the second assumption underlying our analytical solution, is also investigated by numerical calculation of the lower bounds. This method can be straightforwardly extended to uncertainty in other system parameters.
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http://dx.doi.org/10.1117/1.JBO.27.8.085001 | DOI Listing |
Sci Rep
January 2025
LCEA Laboratory, Faculty of Sciences, Mohammed Premier University, Oujda, Morocco.
In the current investigation, the efficiency inhibition of two newly synthesized bi-pyrazole derivatives, namely 2,3-bis[(bis((1 H-pyrazol-1-yl) methyl) amino)] pyridine (Tetra-Pz-Ortho) and 1,4-bis[(bis((1 H-pyrazol-1-yl) methyl) amino)] benzene (Tetra-Pz-Para) for corrosion of carbon steel (C&S) in 1 M HCl medium was evaluated. A Comparative study of inhibitor effect of Tetra-Pz-Ortho and Tetra-Pz-Para was conducted first using weight loss method and EIS (Electrochemical Impedance Spectroscopy) and PDP (Potentiodynamic Polarisation) techniques. Tetra-Pz-Ortho and Tetra-Pz-Para had a maximum inhibition efficacy of 97.
View Article and Find Full Text PDFAnal Chim Acta
March 2025
Department of Materials Science and Engineering, University of Utah, Salt Lake City, UT, 84112, USA. Electronic address:
Background: Perfluorooctane sulfonate (PFOS), one of the most harmful members of the large group of per- and poly-fluoroalkyl substances (PFAS), is notorious for its environmental persistence, bioaccumulation, and toxic effects, raising serious environmental and health concerns. Developing rapid and sensitive methods to detect PFOS in water is critical for effective monitoring and protection against this hazardous chemical.
Results: In this study, we developed rapid and highly sensitive fluorometric sensors (PDI-2+ , PDI-6+ ) for detecting PFOS.
J Pharm Sci
January 2025
Ionis Pharmaceuticals, Inc., 2855 Gazelle Ct., Carlsbad, CA 92010. Electronic address:
Complexes formed between aluminum cluster molecules that adopt a Ɛ-Al-Keggin structure and antisense oligonucleotides were observed as new impurity peaks during drug product stability testing. The Ɛ-Al-Keggin molecules were determined to be artifacts of the analysis, originating from contact between antisense oligonucleotide drug product solution and aluminum weigh boats used to prepare the analytical sample solutions The presence of the Ɛ-Al-Keggin molecules was confirmed through synthesis of the Keggin molecule through an established route and subsequent spiking studies. Binding affinity studies revealed that the Ɛ-Al-Keggin bound to oligonucleotide sequences of various lengths (10 to 20 bases) and base compositions, though there is some evidence for preferential binding to 5-methylcytosine-containing sequences.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
State Key Laboratory of Medicinal Chemical Biology, Frontiers Science Centre for New Organic Matter, Tianjin Key Laboratory of Biosensing and Molecular Recognition, Research Centre for Analytical Sciences, College of Chemistry, School of Medicine and Frontiers Science Center for Cell Responses, Nankai University, Tianjin 300071, P. R. China.
Carbon monoxide (CO) gas therapy, as an emerging therapeutic strategy, is promising in tumor treatment. However, the development of a red or near-infrared light-driven efficient CO release strategy is still challenging due to the limited physicochemical characteristics of the photoactivated carbon monoxide-releasing molecules (photoCORMs). Here, we discovered a novel photorelease CO mechanism that involved dual pathways of CO release via photosensitization.
View Article and Find Full Text PDFJ Phys Chem B
January 2025
Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), Kaiserstraße 12, 76131 Karlsruhe, Germany.
Implicit solvation models permit the approximate description of solute-solvent interactions, where water is the most often considered solvent due to its relevance in biological systems. The use of other solvents is less common but is relevant for applications such as in nuclear magnetic resonance (NMR) or chromatography. As an example, chloroform is commonly used in anisotropic NMR to measure residual dipolar couplings (RDCs) of chiral analytes weakly aligned by an alignment medium.
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