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Fully convolutional networks in multimodal nonlinear microscopy images for automated detection of head and neck carcinoma: A pilot study
摘要： Background: A fully convolutional neural networks (FCN)-based automated image analysis algorithm to discriminate between head and neck cancer and non-cancerous epithelium based on nonlinear microscopic images was developed. Methods: Head and neck cancer sections were used for standard histopathology and co-registered with multimodal images from the same sections using the combination of coherent anti-Stokes Raman scattering, two-photon excited fluorescence, and second harmonic generation microscopy. The images analyzed with semantic segmentation using a FCN for four classes: cancer, normal epithelium, background, and other tissue types. Results: A total of 114 images of 12 patients were analyzed. Using a patch score aggregation, the average recognition rate and an overall recognition rate or the four classes were 88.9% and 86.7%, respectively. A total of 113 seconds were needed to process a whole-slice image in the dataset. Conclusion: Multimodal nonlinear microscopy in combination with automated image analysis using FCN seems to be a promising technique for objective differentiation between head and neck cancer and noncancerous epithelium.
关键词： digital pathology,semantic segmentation,diagnostics,second-harmonic generation,convolutional neural networks,two-photon excited fluorescence,spectral histopathology,image analysis,head and neck cancer,coherent anti-stokes Raman scattering
更新于2025-09-04 15:30:14
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[IEEE 2018 20th International Conference on Transparent Optical Networks (ICTON) - Bucharest (2018.7.1-2018.7.5)] 2018 20th International Conference on Transparent Optical Networks (ICTON) - Three-Dimensional Photonic Structures Fabricated by Two-Photon Polymerization for Microfluidics and Microneedles
摘要： Polymer micro- and nanostructures with various geometries, such as lines, gratings, woodpiles or dots, can be written onto a transparent substrate by the technique of two-photon polymerization, i.e. focusing a femtosecond laser into a liquid acrylate based resin containing a photo-initiator. The microstructures can be also employed to mimic features found in nature for controlled wetting or liquid transport. Similar structures can be implemented into channels of microfluidic devices to control the transport of fluids herein. In preliminary experiments, we were able to produce microneedles ornamented with microstructures which would facilitate the transport of an aqueous liquid to the needle tip.
关键词： two-photon polymerization,directed fluid transport,microneedles,microfluidics,photonic structures
更新于2025-09-04 15:30:14
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A Comparison of Different Corneal Iontophoresis Protocols for Promoting Transepithelial Riboflavin Penetration
摘要： PURPOSE. To measure corneal riboflavin penetration using different transepithelial iontophoresis protocols. METHODS. Freshly enucleated rabbit eyes were divided into nine treatment groups of 4 eyes. One group, in which 0.1% wt/vol riboflavin was applied for 30 minutes without iontophoresis after corneal epithelial debridement, acted as a control. The remaining groups were treated with an intact epithelium using different riboflavin formulations and varying iontophoresis current, soak, and rinse times. After riboflavin application, eyes were snap frozen in liquid nitrogen. Corneal cross sections 35 lm thick were then imaged immediately by two-photon fluorescence microscopy, using image processing software to quantify stromal riboflavin concentration at different corneal depths. RESULTS. In the epithelium-on iontophoresis treatment groups, greater stromal riboflavin penetration was achieved with higher-concentration riboflavin solutions, greater iontophoresis dosage, and longer solution contact times. A protocol utilizing 0.25% wt/vol riboflavin with benzalkonium chloride (BAC) 0.01% and two cycles of applied current and subsequent soaking (1 mA 5 minutes, soak 5 minutes; 0.5 mA 5 minutes, soak 5 minutes) achieved similar stromal riboflavin penetration to epithelium-off controls. The best-performing non-BAC-containing protocol produced stromal riboflavin penetration approximately 60% that of epithelium-off controls. Riboflavin solutions containing saline resulted in minimal stromal penetration. Riboflavin loading within the epithelium was equivalent to or higher than that in the subjacent stroma, despite rinsing the ocular surface with balanced salt solution. CONCLUSIONS. Modified iontophoresis protocols can significantly improve transepithelial riboflavin penetration in experimental corneal collagen cross-linking.
关键词： iontophoresis,riboflavin,two-photon fluorescence microscopy,corneal cross-linking,transepithelial
更新于2025-09-04 15:30:14
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Fabrication and tribological characterization of deformation-resistant nano-textured surfaces produced by two-photon lithography and atomic layer deposition
摘要： In this study, we demonstrated a novel strategy for fabricating deformation-resistant nano-textured surfaces. Ordered arrays of IP-DIP photoresist nanodots of various diameters were first fabricated using two-photon lithography. IP-DIP/Al2O3 core-shell nanostructures (CSNs) were then formed by conformally coating the nanodots with Al2O3 of different thicknesses via atomic layer deposition (ALD). The CSNs showed 85% lower coefficients of friction than the bare IP-DIP nanodots and exhibited minimal nanostructure deformation at contact pressures greater than 20 GPa. The IP-DIP/Al2O3 CSNs also have lower adhesion forces than the bare IP-DIP nanodots. The excellent deformation resistance and superior tribological properties of these CSNs demonstrate that the combination of two-photon lithography and ALD is a very promising solution to tribological issues in miniaturized systems.
关键词： Surface Texturing,Atomic Layer Deposition.,Two-Photon Lithography,Core-Shell Nanostructures
更新于2025-09-04 15:30:14
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BODIPY with Tuned Amphiphilicity as Fluorogenic Plasma Membrane Probe
摘要： Staining of the plasma membrane (PM) is essential in bio-imaging as it delimits the cell surface and provides various information regarding the cell morphology and status. Herein, the lipophilicity of a green-emitting BODIPY fluorophore was tuned by gradual functionalization with anchors composed of zwitterionic and aliphatic groups, thus yielding three different amphiphilic dyes. We found that BODIPY bearing one or three anchors failed in efficiently staining the PM: derivative with one anchor showed low affinity to PM and exhibited strong fluorescence in water due to high solubility, whereas BODIPY with three anchors aggregated strongly in media and precipitated before binding to PM. In sharp contrast, the BODIPY bearing two anchors (B-2AZ, MemBright-488) formed virtually non-fluorescent soluble aggregates in aqueous medium that quickly de-aggregated in the presence of PM leading to bright soluble molecular form (quantum yield of 0.92). This fluorogenic response allowed for efficient probing of the PM at low concentration (20 nM) with high signal to background ratio images in mono- as well as two-photon excitation microscopy. B-2AZ proved to selectively stain the PM in a more homogeneous manner than the commercially available fluorescently labelled lectin WGA. Finally, it was successfully used in 3D-imaging to reveal fine intercellular tunneling nanotubes in KB cells and to stain the PM in glioblastoma cells in spheroids.
关键词： tunneling nanotubes,two-photon imaging,spheroids,Plasma membrane probe,fluorogenic probe
更新于2025-09-04 15:30:14
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All-Optical Poling and Two-Photon Absorption in Heterocyclic Azo Dyes with Different Side Groups
摘要： We investigated the optical properties of heterocyclic azo dyes with different side groups prepared: as powders, in PMMA matrix and side-chain polymers. We characterized the nonlinear optical effects of these compounds by Z-scan and all-optical poling techniques and supported these experiments with theoretical modeling. It was also found that these materials show strong two-photon absorption cross-sections exceeding 20 GM, which is one order of magnitude stronger than that of similar materials (azobenzene and p-aminoazobenzene). Our study reveals the dominant role of the side-chain system over the guest-host one and stress out the importance of the substituent in the efficiency of the poling process.
关键词： All-Optical Poling,Hybrid Materials,Heterocyclic Azo Dyes,Two-Photon Absorption,Plasmonics,Optical,Magnetic
更新于2025-09-04 15:30:14
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Fast response two-photon fluorogenic probe based on Schiff base derivatives for monitoring nitric oxide levels in living cells and zebrafish
摘要： Numerous excellent fluorogenic probes for NO detection based on NO-mediated reactions have been developed. However, some of them still suffer from limitations such as low selectivity, slow response, and a short excitation wavelength (o500 nm). Herein, a novel two-photon fluorogenic probe (XNO1) based on a Schiff base derivative has been reported for the first time. This new mechanism with a Schiff base structure as the specific response moiety towards NO endows the probe with fast responsibility, high selectivity and pH-independent properties. Furthermore, XNO1 has been demonstrated to be lysosome-targeted and to successfully monitor exogenous/endogenous NO in living cells and zebrafishes with one- and two-photon fluorescence imaging.
关键词： living cells,nitric oxide,two-photon fluorogenic probe,zebrafish,Schiff base derivatives
更新于2025-09-04 15:30:14
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Label-free detection of brain invasion in meningiomas by multiphoton microscopy
摘要： Brain invasion in meningiomas relates to the poor prognosis. Therefore, accurate detection and treatment of brain invasion are of particular importance. In this study, multiphoton microscopy (MPM) was introduced for label-free detection of brain invasion in meningiomas by the combination of the two-photon excited fluorescence imaging, second-harmonic generation imaging and spectral imaging. Results show that MPM has the ability to morphologically and spectrally identify brain invasion in meningiomas. What is more, the intensity ratios of the cerebral cortex over meningiomas at 475 nm, 511 nm and 540 nm were extracted as quantitative indicators for differentiating meningioma from surrounding normal cerebral cortex tissue. Together with custom-developed image processing algorithms, MPM could further identify the tumor boundary. With miniaturization and optimization of probes and optical fiber for in vivo imaging, combined with a laser ablation system, MPM would be used in an operating room for both the diagnosis and treatment of brain invasion in meningiomas.
关键词： brain invasion,two-photon excited fluorescence,multiphoton microscopy,second harmonic generation
更新于2025-09-04 15:30:14
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Synthesis, Photophysical Properties and Two Photon Absorption Study of Tetraazachrysene‐based N‐heteroacenes
摘要： Three novel N-heteroacene molecules (SDNU-1, SDNU-2 and SDNU-3) based on tetraazachrysene units as cores have been designed, synthesized and fully characterized. Their photophysical, electrochemical and fluorescence properties were investigated, and they exhibited blue to green emission in solid state. Interestingly, SDNU-2 exhibited high solid photoluminescence quantum efficiencies (75.3%), which is the highest value of N-heteroacenes derivatives to date. Two-photon absorption studies have been conducted by using open and close aperture Z-scan technique. SDNU-3 showed a significant enhancement in the two-photon absorption cross-section with magnitudes as high as ～700 GM (1 GM = 1 × 10–50 cm4 s/photon) when excited with 800 nm light, which is the largest value based on heteroacene system measured by Z-scan experiment so far. We attribute the outcome to sufficient electronic coupling between the strong charge transfer of quadrupolar substituents and the tetraazachrysene core. Our result would provide a new guideline to design novel efficient two-photon materials based on N-heteroacene cores.
关键词： Synthesis,Fluorescence quantum yields,Azaacenes,Two Photon Absorption
更新于2025-09-04 15:30:14