Search results for "Microscope"
showing 10 items of 1412 documents
Light field propagation by metal micro- and nanostructures
2001
The ability to sustain plasmon oscillations gives rise to unique properties of metal nanostructures, which can be exploited for the controlled manipulation of light fields on the nanoscale. In this context we investigate electromagnetic coupling effects within lithographically produced ensembles of gold nanoparticles with a photon scanning tunnelling microscope. To provide an interface between these nano-optical devices and classical far-field optics, we investigate surface plasmon propagation on microstructured metal thin films.
In vivo detection of cytokeratin filament network breakdown in cells treated with the phosphatase inhibitor okadaic acid.
2001
We have previously described vulva carcinoma-derived A-431 subclone AK13-1, which stably expresses fluorescently labeled cytokeratin filaments (CKFs). Time-lapse fluorescence microscopy of these cells permits the continuous monitoring of the dynamics of the CKF cytoskeleton in vivo. To study mechanisms and principles of CKF disassembly as it occurs, e.g., during mitosis and liver disease, we have treated cells with the phosphatase inhibitor okadaic acid (OA), which induces complete CKF network breakdown within 3–5 h without significantly affecting the organization of the actin- and tubulin-based cytofilaments. In time-lapse movies, we find that the network breakdown starts at the cell perip…
Imaging connected porosity of crystalline rock by contrast agent-aided X-ray microtomography and scanning electron microscopy
2017
We set out to study connected porosity of crystalline rock using X-ray microtomography and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS) with caesium chloride as a contrast agent. Caesium is an important radionuclide regarding the final deposition of nuclear waste and also forms dense phases that can be readily distinguished by X-ray microtomography and SEM-EDS. Six samples from two sites, Olkiluoto (Finland) and Grimsel (Switzerland), where transport properties of crystalline rock are being studied in situ, were investigated using X-ray microtomography and SEM-EDS. The samples were imaged with X-ray microtomography, immersed in a saturated caesium chlorid…
Dual drug-loaded halloysite hybrid-based glycocluster for sustained release of hydrophobic molecules
2016
A dual drug-loaded HNT–CD glycocluster delivery system based on halloysite nanotubes and carbohydrate functionalized cyclodextrin was developed by a green protocol using solvent-free microwave irradiation. The nanohybrid was employed for concurrent load and release of silibinin and curcumin. The new delivery system was characterized by means of TGA, FT-IR spectroscopy, SEM and DLS. These techniques confirm the successful loading of the two drugs in the system. SEM and DLS measurements highlighted that the nanomaterial preserves a tubular structure with an average hydrodynamic radius of ca. 200 nm. The release of the drugs from the HNT glycocluster was investigated by means of UV-vis spectro…
Osteogenesis imperfecta and hyperplastic callus formation: light- and electron-microscopic findings.
1993
In rare cases of osteogenesis imperfecta, an "overshoot" growth of new bone may occur, which, clinically gives the impression of a tumour. This condition is known as hyperplastic callus formation. Morphology showed an excessive mixed desmal-chondral osteoneogenesis. Atypical collagen fibrils in non-callus tissue represent an indicator for this callus formation in individual patients.
Digital Image Processing in the Analysis of Astrometric Plates
1991
AbstractIn this paper, we display an improvement to our process of semi-automatic measuring of astrometric plates, in which the photometric sensor is substituted by a CCD system of image getting and digitalization. The advantages of this method are analyzed taking into account the possibilities of the image analysis in the space and frequency domain.
Numerical simulations of photon scanning tunneling microscopy: role of a probe tip geometry in image formation
2005
Abstract Numerical simulations of two-dimensional probe–object system emulating a photon scanning tunnelling microscope are presented. R -matrix propagation algorithm incorporated into the differential method was used to achieve an extended capability to rigorously model a realistic system consisting of both a probe and a sample. Influence of the probe tip parameters on image formation in scanning near-field microscopy has been investigated. Coupling of the near-field to a single-mode probe and formation of a guided fundamental mode in a probe were investigated for various probe widths and lengths. The influence of the probe taper shape and apex size on near-field images was studied for sin…
Analysis of image formation with a photon scanning tunneling microscope
1996
International audience; The photon scanning tunneling microscope (PSTM) is based on the frustration of a total internal reflected beam by the end of an optical fiber. Until now it has been used to obtain topographic information, generally for smooth samples. We report theoretical as well as experimental results on the observation of a step on a quartz substrate with the PSTM. These results demonstrate the effects on image formation of the distance between the fiber tip and the sample surface, the orientation of the incident beam with respect to the step, the polarization, and the coherence of the light. Good agreement exists between numerical simulations and experiments. We show that a pert…
Human macrophages simultaneously express membrane-C1q and Fc-receptors for IgG
2005
Membrane C1q (mC1q) of macrophages (MPhi) is a precursor of the IgG-binding serum protein C1q. Thus, mC1q potentially provides one of several Fcgamma binding sites of mature MPhi and we analyzed whether simultaneous expression occurs of established receptors for IgG, FcgammaRI, II, and III, and mC1q during in vitro differentiation of MPhi. Using flow cytometry, immunoprecipitation combined with Western blotting and Northern blot analysis mC1q was hardly detected in freshly isolated blood monocytes, but increasingly in developing monocyte-derived MPhi. Laser scanning fluorescence microscopy confirmed the membrane localization of mC1q. Two-color-staining flow cytometry experiments indicated t…
A Protein-Interaction Array Inside a Living Cell
2013
Cell phenotype is determined by protein network states that are maintained by the dynamics of multiple protein interactions.1 Fluorescence microscopy approaches that measure protein interactions in individual cells, such as by Forster resonant energy transfer (FRET), are limited by the spectral separation of fluorophores and thus are most suitable to analyze a single protein interaction in a given cell. However, analysis of correlations between multiple protein interactions is required to uncover the interdependence of protein reactions in dynamic signal networks. Available protein-array technologies enable the parallel analysis of interacting proteins from cell extracts, however, they can …