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Evaluation of the corneal epithelium in non-Sj?gren’s and Sj?gren’s dry eyes: an in vivo confocal microscopy study using HRT III RCM
摘要： Background: The corneal epithelium is directly affected in dry eye syndrome. Thus, we attempted to describe the morphological features and evaluate the cellular density within the corneal epithelial layers in patients with non-Sj?gren’s (NSDE) and Sj?gren’s syndrome dry eyes (SSDE) by in vivo confocal microscopy (IVCM). Methods: Central cornea was prospectively imaged by IVCM in 68 clinically diagnosed aqueous tear-deficient dry eyes and 10 healthy age-matched control eyes. Morphological characteristics of corneal epithelial layers and cellular densities were evaluated by four trained graders from the Doheny Eye Institute. Results: Corneal epithelium in dry eyes presents morphological changes such as areas of enlarged and irregular shaped cells. In comparison with controls, the density of superficial epithelial cells was decreased in both the NSDE (P < 0.05) and SSDE groups (P < 0.01); the density of the outer layer of wing cells was smaller but not significantly different in NSDE (P > 0.05), but was lower in the SSDE group (P < 0.01); the density of the inner layer of wing cells was decreased in both the NSDE (P < 0.05) and SSDE groups (P < 0.01) and the density of basal epithelial cells was lower in both the NSDE (P < 0.01) and SSDE groups (P = 0.01). For all cell counts, the interclass correlation coefficient showed good agreement between graders (ICC =0.75 to 0.93). Conclusions: IVCM represents a reliable technique for examining the corneal epithelial microstructural changes associated with dry eyes, as well as for objectively and reproducibly quantifying cell densities within all corneal epithelial layers.
关键词： Dry eye syndrome,corneal epithelium,Sj?gren’s syndrome,in vivo laser scanning confocal microscopy
更新于2025-09-04 15:30:14
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Origin of Waveguiding in Ultrashort Pulse Structured Silicon
摘要： The origin of waveguiding in the bulk of silicon after sub-ps laser inscription is investigated. Locally resolved Raman measurements of waveguide cross sections and along the propagation axis reveal highly localized crystal deformations. These modifications consist of highly confined regions of silicon with a disturbed crystal structure accompanied with strain. This transformation is responsible for a local increase of the refractive index allowing localized waveguiding. On the basis of near-field measurements at an excitation wavelength of 1550 nm, the absolute value of the refractive index change is estimated to be in the range of 10?3.
关键词： raman microscopy,silicon waveguide,laser inscription,ultrashort pulses
更新于2025-09-04 15:30:14
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Feature-based Classification of Protein Networks using Confocal Microscopy Imaging and Machine Learning
摘要： Fluorescence imaging has become a powerful tool to investigate complex subcellular structures such as cytoskeletal filaments. Advanced microscopes generate 3D imaging data at high resolution, yet tools for quantification of the complex geometrical patterns are largely missing. Here we present a computational framework to classify protein network structures. We developed a machine-learning method that combines state-of-the-art morphological quantification with protein network classification through morphologically distinct structural features enabling live imaging–based screening. We demonstrate applicability in a confocal laser scanning microscopy (CLSM) study differentiating protein networks of the FtsZ (filamentous temperature sensitive Z) family inside plant organelles (Physcomitrella patens).
关键词： FtsZ,machine learning,classification,protein networks,confocal microscopy
更新于2025-09-04 15:30:14
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Direct formation of gold nanorods on surfaces using polymer-immobilised gold seeds
摘要： Herein, we present the formation of gold nanorods (GNRs) on novel gold–poly(methyl methacrylate) (Au–PMMA) nanocomposite substrates with unprecedented growth control through the polymer molecular weight (Mw) and gold-salt-to-polymer weight ratio. For the first time, GNRs have been produced by seed-mediated direct growth on surfaces that were pre-coated with polymer-immobilised gold seeds. A Au–PMMA nanocomposite formed by UV photoreduction has been used as the gold seed. The influence of polymer Mw and gold concentration on the formation of GNRs has been investigated and discussed. The polymer nanocomposite formed with a lower Mw PMMA and 20 wt % gold salt provides a suitable medium for growing well-dispersed GNRs. In this sample, the average dimension of produced GNRs is 200 nm in length with aspect ratios up to 10 and a distribution of GNRs to nanoparticles of nearly 22%. Suitable characterization techniques such as AFM and SEM have been used to support concept of the proposed growth method.
关键词： direct surface growth,gold nanorods,nanocomposites,atomic force microscopy (AFM),poly(methyl methacrylate) (PMMA)
更新于2025-09-04 15:30:14
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Multimodal cantilevers with novel piezoelectric layer topology for sensitivity enhancement
摘要： Self-sensing techniques for atomic force microscope (AFM) cantilevers have several advantageous characteristics compared to the optical beam deflection method. The possibility of down scaling, parallelization of cantilever arrays and the absence of optical interference associated imaging artifacts have led to an increased research interest in these methods. However, for multifrequency AFM, the optimization of the transducer layout on the cantilever for higher order modes has not been addressed. To fully utilize an integrated piezoelectric transducer, this work alters the layout of the piezoelectric layer to maximize both the deflection of the cantilever and measured piezoelectric charge response for a given mode with respect to the spatial distribution of the strain. On a prototype cantilever design, significant increases in actuator and sensor sensitivities were achieved for the first four modes without any substantial increase in sensor noise. The transduction mechanism is specifically targeted at multifrequency AFM and has the potential to provide higher resolution imaging on higher order modes.
关键词： multimodal AFM,atomic force microscopy,multifrequency AFM,self-sensing,piezoelectric cantilever
更新于2025-09-04 15:30:14
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Nanoparticles at Biomimetic Interfaces: A Combined Experimental and Simulation Study on Charged Gold Nanoparticles/Lipid Bilayers Interfaces
摘要： The poor understanding of the interaction of nanomaterials with biologically relevant interfaces is recognized as one of the major issues currently limiting the development of nanomedicine. The central purpose of this study is to compare experimental (Confocal Microscopy, Fluorescence Correlation Spectroscopy, X-ray Reflectivity) and computational (Molecular Dynamics simulations) results to thoroughly describe the interaction of cationic gold nanoparticles (AuNP) with mixed zwitterionic/anionic lipid membranes. The adhesion of AuNPs to the lipid membrane is investigated on different length scales from a structural and dynamical point of view; with this approach, a series of complex phenomena, spanning from lipid extraction, localized membrane disruption, lateral phase separation and slaved diffusion, are characterized and interpreted from a molecular level to macroscopic observations.
关键词： Nanoparticles,Gold Nanoparticles,Molecular Dynamics,X-ray Reflectivity,Fluorescence Correlation Spectroscopy,Lipid Bilayers,Biomimetic Interfaces,Confocal Microscopy
更新于2025-09-04 15:30:14
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Ultra-Sensitive and Label-Free Probing of Binding Affinity Using Recognition Imaging
摘要： Reliable quantification of binding affinity is important in biotechnology and pharmacology and increasingly coupled with a demand for ultrasensitivity, nanoscale resolution, and minute sample amounts. Standard techniques are not able to meet these criteria. This study provides a new platform based on atomic force microscopy (AFM)-derived recognition imaging to determine affinity by visualizing single molecular bindings on nanosize dendrons. Using DNA hybridization as a demonstrator, an AFM sensor adorned with a cognate binding strand senses and localizes target DNAs at nanometer resolution. To overcome the limitations of speed and resolution, the AFM cantilever is sinusoidally oscillated close to resonance conditions at small amplitudes. The equilibrium dissociation constant of capturing DNA duplexes was obtained, yielding 2.4 × 10?10 M. Our label-free single-molecular biochemical analysis approach evidences the utility of recognition imaging and analysis in quantifying biomolecular interactions of just a few hundred molecules.
关键词： scanning probe microscopy,DNA hybridization,Affinity,molecular recognition,single-molecule
更新于2025-09-04 15:30:14
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Added Value of Microscale Raman Chemical Analysis in Mild Traumatic Brain Injury (TBI): A Comparison with Macroscale MRI
摘要： Di?use axonal injury and microhemorrhages, common complications after mild traumatic brain injury (mTBI), can lead to neurodegeneration and disability and have negative socioeconomic consequences. Magnetic resonance imaging (MRI) is conventionally used to study brain injuries in vivo, but microscale damage common in mTBI is challenging to detect. Raman microscopy is an e?ective diagnostic tool to investigate cells and tissue in a label-free manner, but the scanning mode of Raman microscopy is typically used only in vitro. Here, we show that Raman microscopy complements in vivo MRI, providing the vital information on the structural and molecular changes caused by mTBI in rats. We demonstrate that a method based on Raman microscopy allows us to detect structural damage invisible by conventional MRI and spot molecular changes in protein/lipid concentrations caused by mild TBI.
关键词： Raman microscopy,diffuse axonal injury,mild traumatic brain injury,microhemorrhages,MRI
更新于2025-09-04 15:30:14
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Atomic scale depletion region at one dimensional MoSe <sub/>2</sub> -WSe <sub/>2</sub> heterointerface
摘要： Lateral heterojunctions based on two dimensional (2D) transition metal dichalcogenides (TMDCs) potentially realize monolayer devices exploiting 2D electronic structures and the functions introduced by the presence of 1D heterointerfaces. Electronic structures of a lateral MoSe2-WSe2 junction have been unveiled using scanning tunneling microscopy and spectroscopy. A smooth and narrow depletion region exists despite a defect-rich heterointerface deviating from the preferred zigzag orientations of the TMDC lattice. From the characteristics of the depletion region, a high carrier concentration and high internal electric fields are inferred, offering to benefit designs of lateral TMDC devices.
关键词： depletion region,MoSe2-WSe2,heterointerface,scanning tunneling microscopy,scanning tunneling spectroscopy,TMDCs
更新于2025-09-04 15:30:14
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Optical coupling between resonant dielectric nanoparticles and dielectric nanowires probed by third harmonic generation microscopy
摘要： Localized electromagnetic modes and negligible Ohmic losses dictate the growing interest to subwavelength all-dielectric nanoparticles. Although an exhaustive volume of literature dealt with interaction of all-dielectric nanostructures with free-space electromagnetic fields, they received little attention as integrated photonic elements. We present an experimental and numerical study of optical coupling between a resonant subwavelength silicon nanodisk and a silicon nanowire, as probed by third harmonic generation microscopy and full-wave simulations. First, by placing the nanodisks at different distances from the nanowire, we observed third harmonic intensity modulation by a factor of up to 4.5. This modulation is assigned to changes in the local field enhancement within the nanodisks caused by their coupling to the nanowires and subsequent shifting and broadening of their magnetic-type resonances. Interestingly, although the nanowire presents an additional loss channel for the nanodisk, we observed an increase in the local field strength within the nanodisk, as verified by rigorous full-wave simulations. Inversely, for the gap sizes that are smaller than ≈ 200 nm, we observe the influence of the nanoparticles on the propagation properties of the fundamental waveguide modes of the nanowire. The better understanding of the mutual influence of the Mie-resonant nanoparticles and waveguiding structures heralds integration of the former on photonic chips.
关键词： dielectric nanowire,third harmonic generation microscopy,silicon nanoparticles,Optical coupling
更新于2025-09-04 15:30:14