Despite their modest spatial resolution, uncoated tapered fiber probes are now widely used by the nano-optics community for mapping, with scanning near-field optical microscopy (SNOM), the nonradiative fields at the surface of optical and plasmonic microstructures and nanostructures. Given the significant complexity of the vectorial optical phenomena associated with subwavelength structures, the correct interpretation of SNOM acquisitions requires a complete and accurate understanding of the intrinsic image-formation procedure. In this theoretical study, we show that the SNOM imaging process with uncoated tapered fiber probes is highly polarization dependent and that the dominant effect is, surprisingly, the choice of optical fiber from which the tapered probe was fabricated. We demonstrate that although a tapered monomode fiber is unable to collect the component of the vector electric field parallel to the tip axis, a tapered multimode fiber can successfully collect all the three field components. However, we show that the signal from the longitudinal field component is collected only 10% as efficiently as the signal from the two transverse field components.
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http://dx.doi.org/10.1364/OL.35.000357 | DOI Listing |
ACS Nano
January 2025
State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Chemistry and Chemical Engineering, Donghua University, Shanghai 201620, China.
Electron transfer is ubiquitous in many chemical reactions and biological phenomena; however, the spatial heterogeneities of electron transfer kinetics in electrocatalysis are so far insufficiently resolved. Measuring and understanding the localized electron transfer are crucial to deciphering the intrinsic activity of electrocatalysts and to achieving further improvements in performance. By using scanning electrochemical probe microscopy to spatially resolve redox electrochemistry across the single-crystalline surface of gold microplates, we discover an intriguing radially distributed electron transfer pattern, where the kinetics around the periphery region are significantly higher than those at the central region, regardless of the redox reaction types.
View Article and Find Full Text PDFMicrovasc Res
January 2025
Primary Health Care Center, Department of Health, Medicine and Caring Sciences, Faculty of Medicine and Health Sciences, Linköping University, Linköping, Sweden; Wallenberg Centre for Molecular Medicine, Linköping University, Linköping, Sweden. Electronic address:
Introduction: Little is known about the day-to-day variability of different skin microcirculation parameters, and how this variability is influenced by age and sex. The aim was to examine the day-to-day variability of microcirculatory parameters in relation to age and sex.
Methods: The cutaneous microcirculation was measured using a fiber optic probe integrating laser Doppler flowmetry (LDF) and diffuse reflectance spectroscopy (DRS) to measure oxygen saturation, red blood cell (RBC) tissue fraction, speed-resolved and conventional perfusion.
Biosens Bioelectron
January 2025
Innovation Center of Functional Genomics and Molecular Diagnostics Technology of Gansu Province, Lanzhou, China.
Improving the sensitivity of biosensor has always the major challenge to measure lower detection concentration of biological samples. In this paper, a novel optical fiber surface plasmon resonance (SPR) biosensor based on TiC MXene/GNRs synergistically highly enhanced sensitivity was proposed. The TiC MXene and GNRs were coated on the optical fiber sensing probe by the electrostatic layer-by-layer (ELBL) assembly method.
View Article and Find Full Text PDFBiophys Rev
December 2024
Amity Institute of Molecular Medicine and Stem Cell Research, Amity University Uttar Pradesh, 201313 Noida, India.
Amyloid fibrils, historically stigmatized due to their association with diseases like Alzheimer's and Parkinson's, are now recognized as a distinct class of functional proteins with extraordinary potential. These highly ordered, cross-β-sheet protein aggregates are found across all domains of life, playing crucial physiological roles. In bacteria, functional amyloids like curli fibers are essential for surface adhesion, biofilm formation, and viral DNA packaging.
View Article and Find Full Text PDFRNA-binding proteins (RBPs) are critical regulators of mRNAs controlling all processes such as RNA transcription, transport, localization, translation, mRNA:ncRNA interactions, and decay. Cellular differentiation is driven by tissue-specific and/or tissue-preferred expression of proteins needed for the optimal function of mature cells, tissues and organs. Lens fiber cell differentiation is marked by high levels of expression of crystallin genes encoding critical proteins for lens transparency and light refraction.
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