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A machine learning approach for online automated optimization of super-resolution optical microscopy
摘要： Traditional approaches for finding well-performing parameterizations of complex imaging systems, such as super-resolution microscopes rely on an extensive exploration phase over the illumination and acquisition settings, prior to the imaging task. This strategy suffers from several issues: it requires a large amount of parameter configurations to be evaluated, it leads to discrepancies between well-performing parameters in the exploration phase and imaging task, and it results in a waste of time and resources given that optimization and final imaging tasks are conducted separately. Here we show that a fully automated, machine learning-based system can conduct imaging parameter optimization toward a trade-off between several objectives, simultaneously to the imaging task. Its potential is highlighted on various imaging tasks, such as live-cell and multicolor imaging and multimodal optimization. This online optimization routine can be integrated to various imaging systems to increase accessibility, optimize performance and improve overall imaging quality.
关键词： machine learning,multicolor imaging,online automated optimization,live-cell imaging,super-resolution optical microscopy,multimodal optimization
更新于2025-09-04 15:30:14
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Development of a scanning probe microscopy integrated atomic layer deposition system for <i>in situ</i> successive monitoring of thin film growth
摘要： A dual chamber system integrated with atomic layer deposition (ALD) and atomic force microscopy (AFM) was developed for the successive monitoring of nanoparticles to thin film growth process. The samples were fabricated in the ALD chamber. A magnetic transmission rod enabled sample transferring between the ALD and the AFM test chambers without breaking the vacuum, avoiding possible surface morphology change when frequently varying the growth condition and oxidation under ambient condition. The sample transmission also avoids deposition and contamination on the AFM tip during the successive testing. The sample stage has machined a group of accurate location pinholes, ensuring the 10 μm2 measurement consistency. As a demonstration, the platinum thin films with different thickness were fabricated by varying ALD cycles. The surface morphology was monitored successively during the deposition. Under vacuum with controlled oxygen partial pressure, the aging and sintering phenomenon of particles has been studied in the AFM testing chamber after high temperature treatment. The integrated AFM/ALD instrument is potentially a powerful system for monitoring the thin film preparation and characterization.
关键词： platinum thin films,atomic force microscopy,in situ monitoring,atomic layer deposition,thin film growth
更新于2025-09-04 15:30:14
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Fabricated Pt–C-Mesoporous TiO <sub/>2</sub> for the Photoreduction of CO <sub/>2</sub> Into Renewable Hydrocarbon Fuels
摘要： Various Pt-supported mesoporous TiO2 catalysts (0.5–1.5 wt%) were prepared using a hydrothermal approach. The photocatalytic activity of the catalysts in CO2 photoreduction was tested in the gaseous phase while using H2O as an electron donor and a Hg lamp as the UV light source. The results showed that the Pt–C-meso-TiO2 has a large surface area, which can increase the CO2 absorption capacity. The CH4 production of Pt–C-meso-TiO2 increased while the charge separation increased. The amount of Pt loaded onto TiO2 was optimized, with 1.0 wt% showing the highest photocatalytic activity (the CH4 production rate of 1.0 wt% Pt–C-meso-TiO2 reached 20.23 μmol · h?1g?1 under the UV light source. Moreover, 1.0 wt% Pt–C-meso-TiO2 can be used repeatedly with a negligible loss of photocatalytic activity after 60 days. Furthermore, a mechanism of the photoreduction of CO2 was proposed. Therefore, Pt–C-meso-TiO2 is an efficient photocatalyst for the photoreduction of CO2 to CH4.
关键词： Semiconductors,Electron Microscopy,Chemical Synthesis,Electrochemical Properties
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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Application of In Vivo Confocal Microscopy in Dry Eye Disease
摘要： Confocal microscopy is a new, emerging, noninvasive technology that can aid in the in vivo assessment of structural changes in several ocular surface diseases at the cellular level. In the dry eye field, in vivo confocal microscopy has been applied to the examination of the cornea, bulbar and palpebral conjunctiva, Meibomian gland, and lacrimal gland. The device can assess the morphology, including superficial/wing/basal epithelial cell density, stromal keratocyte density, endothelial cell density, nerve fiber density, the number of beadings, nerve tortuosity, nerve reflectivity, and inflammatory cell density in the cornea. Furthermore, the device can not only assess epithelial cell density and area, goblet cell, microcyst, and inflammatory cell density but also the cellular architecture, including nucleocytoplasmic ratio in conjunctiva. The device also can disclose acinar unit density, acinar unit longest diameter, acinar unit shortest diameter, and inflammatory cell density in the Meibomian gland and lacrimal gland by other potential applications. Relevant research in Europe and the United States focused on the morphologic changes in the cornea in the dry eye field, while Japanese research focused on the conjunctival, Meibomian gland, and lacrimal gland alterations. The application of in vivo confocal microscopy in dry eye disease will be a powerful method to evaluate the morphologic change of the ocular surface around the world in the future.
关键词： dry eye,conjunctiva,Meibomian gland,confocal microscopy,lacrimal gland,cornea
更新于2025-09-04 15:30:14
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Carbon Nanomembranes
摘要： This chapter describes the formation and properties of one nanometer thick carbon nanomembranes (CNMs), made by electron induced cross-linking of aromatic self-assembled monolayers (SAMs). The cross-linked SAMs are robust enough to be released from the surface and placed on solid support or over holes as free-standing membranes. Annealing at ~1000K transforms CNMs into graphene accompanied by a change of mechanical stiffness and electrical resistance. The developed fabrication approach is scalable and provides molecular level control over thickness and homogeneity of the produced CNMs. The mechanisms of electron-induced cross-linking process are discussed in details. A variety of polyaromatic thiols: oligophenyls as well as small and extended condensed polycyclic hydrocarbons have been successfully employed, demonstrating that the structural and functional properties of the resulting nanomembranes are strongly determined by the structure of molecular monolayers. The mechanical properties of CNMs (Young’s modulus, tensile strength and prestress) are characterized by bulge testing. The interpretation of the bulge test data relates the Young’s modulus to the properties of single molecules and to the structure of the pristine SAMs. The gas transport through the CNM is measured onto polydimethylsiloxane (PDMS) - thin film composite membrane. The established relationship of permeance and molecular size determines the molecular sieving mechanism of permeation through this ultrathin sheet.
关键词： Helium Ion Microscopy,radiation induced cross-linking,Self-Assembled Monolayer,Carbon Nanomembrane (CNM),Graphene
更新于2025-09-04 15:30:14
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[IEEE 2018 40th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) - Honolulu, HI (2018.7.18-2018.7.21)] 2018 40th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) - Clumped Nuclei Segmentation with Adjacent Point Match and Local Shape-Based Intensity Analysis in Fluorescence Microscopy Images
摘要： Highly clumped nuclei captured in fluorescence microscopy images are commonly observed in a wide spectrum of tissue-related biomedical investigations. To ensure the quality of downstream biomedical analyses, it is essential to accurately segment clustered nuclei. However, this presents a technical challenge as fluorescence intensity alone is often insufficient for recovering the true nuclei boundaries. In this paper, we propose an segmentation algorithm that identifies point pair connection candidates and evaluates adjacent point connections with a formulated ellipse fitting quality indicator. After connection relationships are determined, we recover the resulting dividing paths by following points with specific eigenvalues from the image Hessian in a constrained searching space. We validate our algorithm with 560 image patches from two classes of tumor regions of seven brain tumor patients. Both qualitative and quantitative experimental results suggest that our algorithm is promising for dividing overlapped nuclei in fluorescence microscopy images widely used in various biomedical research.
关键词： clumped nuclei segmentation,fluorescence microscopy images,adjacent point match,local shape-based intensity analysis
更新于2025-09-04 15:30:14
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Effect of growth pressure on graphene direct growth on r-plane and c-plane sapphires by low-pressure CVD
摘要： Graphene was grown on both r-plane and c-plane sapphires by low-pressure chemical vapor deposition without using a metal catalyst. The growth pressure was systematically changed to investigate how the growth pressure effects the graphene growth. Consequently, it was found that the coverage of the graphene increased with increasing growth pressure on the r-plane sapphire while it decreased with increasing growth pressure on the c-plane sapphire. Raman spectroscopy and atomic force microscopy indicates that the growth layer is single-layer graphene on the r-plane sapphire while it is a bi-layer on the c-plane sapphire. Graphene is thought to grow on the r-plane sapphire simply in a two-dimensional nucleation mode. On the other hand, graphene tends to grow in the pits formed on the surface of the c-plane sapphire. The pits are thought to be produced by the oxygen desorption and have some catalytic effects.
关键词： sapphire,low-pressure CVD,atomic force microscopy,growth pressure,graphene,Raman spectroscopy
更新于2025-09-04 15:30:14
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Effect of surface treatment of printed Ag Schottky contacts on n-GaN epitaxial layers using Ag nanoink: Two dimensional characterization by scanning internal photoemission microscopy
摘要： We report the basic electrical characteristics of Ag Schottky contacts printed on n-GaN epitaxial wafers using Ag nanoink with surface treatment using HCl or an organic solvent. The Ag Schottky contacts treated with HCl showed better current–voltage characteristics and a larger Schottky barrier height than those treated with the organic solvent. Scanning internal photoemission microscopy revealed that the HCl-treated samples exhibited a higher uniformity owing to their higher wettability to the Ag nanoink and electrodes than the organic-solvent-treated samples. These results indicate that the removal of surface oxide layers using HCl is effective even though the GaN surface is printed and annealed in air.
关键词： Ag Schottky contacts,n-GaN,surface treatment,Ag nanoink,scanning internal photoemission microscopy
更新于2025-09-04 15:30:14
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Study of the Interface of the Early Stages of Growth under Quasi-Equilibrium Conditions of ZnO on Graphene/Cu and Graphite
摘要： The study of the early stages of growth of ZnO on graphene supported on Cu and on highly oriented pyrolytic graphite by means of reactive thermal evaporation of metallic Zn at room temperature is presented. This growth method allows to go in depth in the study of the fundamental interaction between ZnO and graphene at the interface in quasi-equilibrium conditions. Quantitative, chemical, and morphological analysis is performed using photoemission spectroscopy, atomic force, and scanning microscopies as experimental characterization techniques and factor analysis and inelastic peak shape analysis as modeling techniques. The growth of ZnO on a highly oriented pyrolytic graphite substrate is also studied using the same growth method for comparison. The results show that, in spite that the first atomic layer of both substrates is identical, the growth kinetics and morphology of the deposits are completely different. A model for the kinetics of the growth of ZnO on both substrates is proposed.
关键词： X-ray photoemission spectroscopy,early stages of growth,ZnO/graphene interfaces,atomic force microscopy,nanostructured ZnO thin films
更新于2025-09-04 15:30:14