- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
<i>In Vivo</i> Confocal Microscopy Analysis of Corneal Microstructural Changes in Neurosurgically-Induced Neurotrophic Keratitis
摘要： Purpose: To investigate the changes of the corneal microstructure of neurosurgically-induced neurotrophic keratitis patients compared to normal human corneas using in vivo confocal microscope (IVCM). Methods: Ten eyes in the normal control group and 11 eyes in the neurosurgically-induced neurotrophic keratitis patient group were included in the present study. After corneal sensitivity tests were performed, thickness of each layer and number of endothelial cells and stromal keratocytes in the cornea were assessed using IVCM. Morphological characteristics of the corneal nerves were measured by ImageJ software. Results: After analysis of corneal thickness layer by layer, the Bowman’s layer was significantly reduced in the neurosurgically-induced neurotrophic keratitis patient group compared with the normal control group (p = 0.016) and the portion of Bowman’s layer was significantly reduced in the neurosurgically-induced neurotrophic keratitis patient group compared with the control group (p = 0.024). The nerve fiber length per square-millimeter became significantly shorter compared to the normal control group (p = 0.042). The nerve fiber length per square millimeter showed significant correlations with the number of fibers, number of beading, branching patterns, and nerve tortuosity (p = 0.002, 0.002, 0.013 and 0.034, respectively). The number of endothelial cells and stromal keratocytes, the number of nerve fibers and beading, and the pattern of branching and nerve tortuosity showed no significant differences between the normal and neurosurgically-induced neurotrophic keratitis patient groups. Conclusions: Our results showed that decreased thickness of Bowman’s layer may be related to the decreased corneal nerve distribution, secondary to the dysfunction of trigeminal nerve branch innervating the cornea. The microstructural changes of Bowman’s layer can help diagnose the disease and evaluate the current status in neurosurgically-induced neurotrophic keratitis patients.
关键词： Neurosurgically-induced neurotrophic keratitis,Corneal thickness,Corneal nerve,Confocal microscopy,Neurosurgery
更新于2025-09-04 15:30:14
-
Deep Learning in Image Cytometry: A Review
摘要： Artificial intelligence, deep convolutional neural networks, and deep learning are all niche terms that are increasingly appearing in scientific presentations as well as in the general media. In this review, we focus on deep learning and how it is applied to microscopy image data of cells and tissue samples. Starting with an analogy to neuroscience, we aim to give the reader an overview of the key concepts of neural networks, and an understanding of how deep learning differs from more classical approaches for extracting information from image data. We aim to increase the understanding of these methods, while highlighting considerations regarding input data requirements, computational resources, challenges, and limitations. We do not provide a full manual for applying these methods to your own data, but rather review previously published articles on deep learning in image cytometry, and guide the readers toward further reading on specific networks and methods, including new methods not yet applied to cytometry data.
关键词： image cytometry,machine learning,biomedical image analysis,convolutional neural networks,deep learning,cell analysis,microscopy
更新于2025-09-04 15:30:14
-
The role of oxygen doping on elemental intermixing at the PVD-CdS/Cu (InGa)Se <sub/>2</sub> heterojunction
摘要： Elemental intermixing at the CdS/CuIn1?xGaxSe2 (CIGS) heterojunction in thin‐film photovoltaic devices plays a crucial role in carrier separation and thus device efficiency. Using scanning transmission electron microcopy in combination with energy dispersive X‐ray mapping, we find that by controlling the oxygen in the sputtering gas during physical vapor deposition (PVD) of the CdS, we can tailor the degree of elemental intermixing. More oxygen suppresses Cu migration from the CIGS into the CdS, while facilitating Zn doping in the CdS from the ZnO transparent contact. Very high oxygen levels induce nanocrystallinity in the CdS, while moderate or no oxygen content can promote complete CdS epitaxy on the CIGS grains. Regions of cubic Cu2S phase were observed in the Cu‐rich CdCuS when no oxygen is included in the CdS deposition process. In the process‐of‐record sample (moderate O2) that exhibits the highest solar conversion efficiency, we observe a ~26‐nm‐thick Cu‐deficient CIGS surface counter‐doped with the highest Cd concentration among all of the samples. Cd movement into the CIGS was found to be less than 10 nm deep for samples with either high or zero O2. The results are consistent with the expectation that Cd doping of the CIGS surface and lack of Zn diffusion into the buffer both enhance device performance.
关键词： scanning transmission electron microscopy,Cu diffusion,Cu (In,Ga)Se2 photovoltaics,CdS structure,STEM‐EDS mapping
更新于2025-09-04 15:30:14
-
Surfactant Free Hydrothermal Synthesis of Zn <sub/>2</sub> SnO <sub/>4</sub> Nanoparticles and Their Functional Properties
摘要： A simple, low temperature, cost effective, surfactant free and scalable synthesis of technologically important Zn2SnO4 (ZTO) nanoparticles with controllable size and shape has been developed. X-ray diffraction (XRD), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM) of the synthesized ZTO nanoparticles revealed the formation of highly pure crystalline ZTO phase with the spinel-like structure. The Raman spectrum of the sample was dominated by the A1g vibration mode of pure ZTO phase. From UV–Vis absorption measurements, a band gap (Eg) of 3.78 eV was determined. The photocatalytic activity of the ZTO nanoparticles was evaluated for the photodegradation of methylene blue (MB) under UV-Vis light irradiation. The ZTO-assisted photocatalytic degradation of MB is complete in 25 minutes indicating good photocatalytic activity of ZTO. Mass spectrometric (MS) analysis of degradation intermediates isolated at regular time intervals reveals the presence of azure A, azure B and thionin which are demethylated products of the MB, indicating that the degradation is initiated by demethylation of the molecule.
关键词： Nanoparticles,Photocatalysis,Zn2SnO4,Transmission electron microscopy,Hydrothermal Synthesis
更新于2025-09-04 15:30:14
-
The self-assembly of DyF3 nanoparticles synthesized by chloride-based route
摘要： The series of DyF3 nanoparticles was synthesized for the first time by a chloride-based route, using the water-soluble dysprosium chloride hexahydrate as a precursor. The synthesized nanoparticles have sizes of 3 to 7 nm, which is the smallest reported size for DyF3 nanoparticles. The influence of precursor concentration in an aqueous solution prior to the chemical reaction on the size of nanoparticles was studied. The influence of microwave-assisted hydrothermal treatment was also studied. The analysis of transmission electron microscopy (TEM) data revealed no correlation between the size of synthesized nanoparticles and the concentration of the aqueous solution. The AC/DC magnetic susceptibility of DyF3 nanoparticles was measured. The dipolar ferromagnetic transition for this sample was not observed down to 1.8 K that can be possibly explained by onset of superparamagnetism. The self-assembly of DyF3 nanoparticles was observed for the first time by analysis of XRD and TEM data and the evidence of superlattice formation along (020) and (210) lattice planes over the size of 20–30 nm (4–5 nanoparticles) was obtained.
关键词： X-ray techniques,Self-assembly,Nanocrystalline materials,Colloidal processing,Crystal structure,Electron microscopy
更新于2025-09-04 15:30:14
-
Label‐Free Metabolic Classification of Single Cells in Droplets Using the Phasor Approach to Fluorescence Lifetime Imaging Microscopy
摘要： Characterization of single cell metabolism is imperative for understanding subcellular functional and biochemical changes associated with healthy tissue development and the progression of numerous diseases. However, single-cell analysis often requires the use of ?uorescent tags and cell lysis followed by genomic pro?ling to identify the cellular heterogeneity. Identifying individual cells in a noninvasive and label-free manner is crucial for the detection of energy metabolism which will discriminate cell types and most importantly critical for maintaining cell viability for further analysis. Here, we have developed a robust assay using the droplet micro?uidic technology together with the phasor approach to ?uorescence lifetime imaging microscopy to study cell heterogeneity within and among the leukemia cell lines (K-562 and Jurkat). We have extended these techniques to characterize metabolic differences between proliferating and quiescent cells—a critical step toward label-free single cancer cell dormancy research. The result suggests a droplet-based noninvasive and label-free method to distinguish individual cells based on their metabolic states, which could be used as an upstream phenotypic platform to correlate with genomic statistics.
关键词： single cell analysis,metabolism,circulating tumor cells,droplet micro?uidics,?uorescence lifetime imaging microscopy,phasor analysis,quiescent stage
更新于2025-09-04 15:30:14
-
Microscopy of the Heart || Optogenetic Tools in the Microscopy of Cardiac Excitation-Contraction Coupling
摘要： Microscopy became a scienti?c investigation method in the seventeenth century with the application of the ?rst build microscopes on biological samples [1, 2]. Soon it became a popular method to stain samples in order to visualise particular (cellular and subcellular) structures [3]. These stains, either based on absorption or ?uorescence, have limitations in respect to their speci?city and are often toxic to cells, which limits investigations to short intervals or even dead samples. In 1987 the idea came up to use a ?uorescent protein that was discovered 25 years before [4], in particular a green ?uorescent protein (GFP) form the medusa Aequorea victoria to label cells and cellular structures [5]. With the sequencing and cloning of GFP, a so-called ‘green revolution’ started, which led to regular usage of ?uorescent proteins as markers or sensors (for details see below) in the majority of cellular research in physiology, microbiology, pharmacology, molecular biology, anatomy, cell biology, biophysics and many other biomedical ?elds. Although the expression of the ?uorescent proteins and their optical investigation can already be regarded as optogenetic tools, this term was only applied when the optical properties of proteins were used to manipulate cells. The best-known example of such a protein is the channelrhodopsin, a light-gated ion channel [6, 7]. When this ion channel is expressed in a membrane and illuminated with light of the appropriate wavelength, the channel will be activated and opened, which results in passive transportation of ions across the membrane and a change of the membrane potential. However, within this chapter we consider both aspects, the observation and the manipulation as optogenetic tools. To use the optogenetic tool, the genes of these proteins need to be transferred into the cells to allow the expression of the protein. For an overview of gene delivery into target cells, see [8].
关键词： channelrhodopsins,cardiac excitation-contraction coupling,F?rster Resonance Energy Transfer,genetically encoded biosensors,Optogenetic tools,microscopy
更新于2025-09-04 15:30:14
-
Synthesis of (BiSe) <sub/> 1+ <i>δ</i> </sub> (Bi <sub/>2</sub> Se <sub/>3</sub> ) <sub/> 1+ <i>γ</i> </sub> (BiSe) <sub/> 1+ <i>δ</i> </sub> TiSe <sub/>2</sub> by Directed Self-Assembly of a Designed Precursor
摘要： The synthesis, structure and properties of a new three constituent heterostructure containing BiSe, Bi2Se3, and TiSe2 layers, each with a different structural motif, is reported. (BiSe)1+δ(Bi2Se3)1+γ(BiSe)1+δTiSe2, where δ and γ are the misfit parameters representing the differences in the in-plane packing density of the constituents, forms via a self-assembly process during low-temperature annealing from precursors with a range of compositions and repeat period thicknesses. This indicates that the compound exists in a relatively broad and deep free-energy minima in the energy landscape. The formation was followed as a function of annealing temperature using X-ray diffraction to determine optimum annealing temperatures and stability range. High-resolution electron microscopy images revealed the layering sequence of the constituents and a supercell within the BiSe layers created by periodic anti-phase boundaries. Temperature dependent electrical transport measurements show unexpected changes in carrier mobility and concentration relative to (BiSe)1.15TiSe2. This study suggests that new ternary and multinary phases containing fragments of known binary phases can be synthesized via precursors that mimic the desired product and that the properties of these new phases with ultrathin constituent thicknesses will probably be different from that expected based on composite behavior.
关键词： X-ray diffraction,electron microscopy,heterostructure,BiSe,self-assembly,TiSe2,Bi2Se3,electrical transport
更新于2025-09-04 15:30:14
-
Combined Raman- and AFM-based detection of biochemical and nanomechanical features of endothelial dysfunction in aorta isolated from ApoE/LDLR?/? mice
摘要： Endothelial dysfunction is recognized as a critical condition in the development of cardiovascular disorders. This multifactorial process involves changes in the biochemical and mechanical properties of endothelial cells leading to disturbed release of vasoprotective mediators. Hypercholesterolemia and increased stiffness of the endothelial cortex are independently shown to result in reduced release of nitric oxide and thus endothelial dysfunction. However, direct evidence linking these parameters to each other is missing. Here, a novel method combining Raman spectroscopy for biochemical analysis and Atomic Force Microscopy (AFM) for analysing the endothelial nanomechanics was established. Using this dual approach, the same areas of native ex vivo aortas were investigated, either derived from mice with endothelial dysfunction (ApoE/LDLR-/-) or wild type mice. In particular an increased intracellular lipid content and elevated cortical stiffness/elasticity was shown in ApoE/LDLR-/- aortas, demonstrating a direct link between endothelial dysfunction, the biochemical composition and the nanomechanical properties of endothelial cells.
关键词： Atomic Force Microscopy,Endothelial dysfunction,hypercholesterolemia,endothelial nanomechanics,Raman spectroscopy
更新于2025-09-04 15:30:14
-
Electron Transport in Nanoporous Graphene: Probing the Talbot Effect
摘要： Electrons in graphene can show diffraction and interference phenomena fully analogous to light thanks to their Dirac-like energy dispersion. However, it is not clear how this optical analogy persists in nanostructured graphene, for example, with pores. Nanoporous graphene (NPG) consisting of linked graphene nanoribbons has recently been fabricated using molecular precursors and bottom-up assembly (Moreno et al. Science 2018, 360, 199). We predict that electrons propagating in NPG exhibit the interference Talbot effect, analogous to photons in coupled waveguides. Our results are obtained by parameter-free atomistic calculations of real-sized NPG samples based on seamlessly integrated density functional theory and tight-binding regions. We link the origins of this interference phenomenon to the band structure of the NPG. Most importantly, we demonstrate how the Talbot effect may be detected experimentally using dual-probe scanning tunneling microscopy. Talbot interference of electron waves in NPG or other related materials may open up new opportunities for future quantum electronics, computing, or sensing.
关键词： multiscale modeling,electron transport,Nanoporous graphene,scanning probe microscopy,Talbot interference
更新于2025-09-04 15:30:14