Suchergebnisse

1 The mechanical construction of the microscope -- 2 Image formation in the microscope -- 3 Objectives and eyepieces -- 4 Illumination of the object -- 5 Polarized light microscopy -- 6 Opaque stop and phase contrast microscopy -- 7 Interference microscopy -- 8 Quantitative microscopy -- 9 Specimen preparation -- 10 Photomicrography -- References and further reading -- Appendix: The care of the microscope.

Lensless microscopy requires the simplest possible configuration, as it uses only a light source, the sample and an image sensor. The smallest practical microscope is demonstrated here. In contrast to standard lensless microscopy, the object is located near the lighting source. Raster optical microscopy is applied by using a single-pixel detector and a microdisplay. Maximum resolution relies on reduced LED size and the position of the sample respect the microdisplay. Contrarily to other sort of digital lensless holographic microscopes, light backpropagation is not required to reconstruct the images of the sample. In a mm-high microscope, resolutions down to 800 nm have been demonstrated even when measuring with detectors as large as 138 μm × 138 μm, with field of view given by the display size. Dedicated technology would shorten measuring time. ; This work has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 737089 and from the Ministry of Science and Innovation, the Spanish State Research Agency and the European Regional Development Fund through project PID2019-105714RB-I00.

[EN] We explore the use of a beamforming method intended for large-area scanning in optical-resolution photoacoustic microscopy. It has been evaluated in a experimental setup that comprises a low-cost laser diode and a phase array with a 128-elements linear probe. Three different beamforming strategies are discussed: no-beamforming, static beamforming and dynamic beamforming. The method has been tested in gelatine-based phantoms as well as ex-vivo organs. Results show that, compared with the other two, dynamic beamforming increases up to 15dB and homogenizes signal-to-noise ratio (SNR) along images of roughly 1 cm2. The method and system presented here could be the baseline for more advanced array-based systems that leverage the low-cost laser sources for clinical applications. ; This research has been supported by the Spanish Ministry of Science, Innovation and Universities through grant Juan de la Cierva - Incorporacion (IJC2018-037897-I), and program Proyectos I+D+i 2019 (PID2019-111436RB-C22). Action co-financed by the European Union through the Programa Operativo del Fondo Europeo de Desarrollo Regional (FEDER) of the Comunitat Valenciana 2014-2020 (IDIFEDER/2018/022). A.C. received financial support from Generalitat Valenciana and Universitat Politecnica de Val ` encia through the grants APOSTD/2018/229 and program PAID-10-19, respectively. ; Cebrecos, A.; García-Garrigós, JJ.; Descals, A.; Jimenez, N.; Benlloch Baviera, JM.; Camarena Femenia, F. (2020). Dynamic beamforming for large area scan in array-based photoacoustic microscopy. IEEE. 1-4. https://doi.org/10.1109/IUS46767.2020.9251519 ; S ; 1 ; 4

Recent research into miniaturized illumination sources has prompted the development of alternative microscopy techniques. Although they are still being explored, emerging nano-light-emitting-diode (nano-LED) technologies show promise in approaching the optical resolution limit in a more feasible manner. This work presents the exploration of their capabilities with two different prototypes. In the first version, a resolution of less than 1 µm was shown thanks to a prototype based on an optically downscaled LED using an LED scanning transmission optical microscopy (STOM) technique. This research demonstrates how this technique can be used to improve STOM images by oversampling the acquisition. The second STOM-based microscope was fabricated with a 200 nm GaN LED. This demonstrates the possibilities for the miniaturization of on-chip-based microscopes. ; This work was partially supported by the European Union's Horizon 2020 research and innovation program under grant agreement No. 737089—ChipScope.

1 Introduction to polymer morphology -- 1.1 Polymer materials -- 1.2 Polymer morphology -- 1.3 Polymer processes -- 1.4 Polymer characterization -- 2 Fundamentals of microscopy -- 2.1 Introduction -- 2.2 Optical microscopy -- 2.3 Scanning electron microscopy (SEM) -- 2.4 Transmission electron microscopy (TEM) -- 2.5 Microscopy of radiation sensitive materials -- 2.6 Analytical microscopy -- 2.7 Quantitative microscopy -- 2.8 Dynamic microscopy -- 3 Imaging theory -- 3.1 Imaging with lenses -- 3.2 Imaging by scanning -- 3.3 Polarizing microscopy -- 3.4 Radiation effects -- 4 Specimen preparation methods -- 4.1 Simple preparation methods -- 4.2 Polishing -- 4.3 Microtomy -- 4.4 Staining -- 4.5 Etching -- 4.6 Replication -- 4.7 Conductive coatings -- 4.8 Yielding and fracture -- 4.9 Freezing and drying methods -- 5 Polymer applications -- 5.1 Fibers -- 5.2 Films and membranes -- 5.3 Engineering resins and plastics -- 5.4 Composites -- 5.5 Emulsions and adhesives -- 5.6 Liquid crystalline polymers -- 6 Problem solving summary -- 6.1 Where to start -- 6.2 Instrumental techniques -- 6.3 Interpretation -- 6.4 Supporting characterizations -- Appendixes -- Appendix I Abbreviations of polymer names -- Appendix II List of acronyms — techniques -- Appendix III Manmade polymeric fibers -- Appendix IV Common commercial polymers and tradenames for plastics, films and engineering resins -- Appendix V General suppliers of EM accessories -- Appendix VI Suppliers of optical and electron microscopes -- Appendix VII Suppliers of x-ray microanalysis equipment.

Many reports state the potential hazards of microplastics (MPs) and their implications to wildlife and human health. The presence of MP in the aquatic environment is related to several origins but particularly associated to their occurrence in wastewater effluents. The determination of MP in these complex samples is a challenge. Current analytical procedures for MP monitoring are based on separation and counting by visual observation or mediated with some type of microscopy with further identification by techniques such as Raman or Fourier-transform infrared (FTIR) spectroscopy. In this work, a simple alternative for the separation, counting and identification of MP in wastewater samples is reported. The presented sample preparation technique with further polarized light optical microscopy (PLOM) observation positively identified the vast majority of MP particles occurring in wastewater samples of Montevideo, Uruguay, in the 70–600 μm range. MPs with different shapes and chemical composition were identified by PLOM and confirmed by confocal Raman microscopy. Rapid identification of polyethylene (PE), polypropylene (PP) and polyethylene terephthalate (PET) were evidenced. A major limitation was found in the identification of MP from non-birefringent polymers such as PVC (polyvinylchloride). The proposed procedure for MP analysis in wastewater is easy to be implemented at any analytical laboratory. A pilot monitoring of Montevideo WWTP effluents was carried out over 3-month period identifying MP from different chemical identities in the range 5.3–8.2 × 10 MP items/m. ; With funding from the Spanish government through the "María de Maeztu Unit of Excellence" accreditation (MDM-2017-0737)

In this research, linear and nonlinear optical properties of NiO nanoparticles (NPs) dissolved in ethanol were investigated. Linear optical characteristics of NiO NPs were studied using a UV-Vis spectrophotometer. The linear absorption coefficient (α0) was 0.88 and 0.57 cm-1 at 405 and 532 nm wavelengths, respectively. The band gap energy rose from 3.56 eV for a sample with a 10-7 g/ml concentration to 3.92 eV for the 10-3 g/ml concentration sample. Using the Z-scan technique, the nonlinear optical characteristics of the NPs were investigated. Two continuous wave laser diodes with 405 and 532 nm wavelengths and different powers were used. The Z-scan system with a closed aperture revealed that NiO NPs have a negative n2 (self-defocusing effect) at various laser powers. n2 increases as the power of the laser increases. The value of n2 was found to be 0.51×10-4 cm2/mW at a wavelength of 405 nm and a power of 0.33 mW. It improved as the laser power increased, reaching a maximum of 0.64×10-4 cm2/mW at a laser power of 1.51 mW. For the laser with a wavelength of 532 nm, the n2 value was 0.27×10-4 cm2/mW for a laser power of 1.01 mW. This value increased to 0.76×10-4 cm2/mW when the laser power increased to 6.2 mW. As measured by the Z-scan system with an open aperture, NiO NPs have a nonlinear absorption coefficient and display a two-photon absorption behavior.

Purpose: 3D imaging of the lung is not a trivial undertaking as during preparation the lung may collapse. Also serial sections and scans followed by 3D reconstruction may lead to artifacts. The present study aims to figure out the best way to perform 3D imaging in lung research. Materials and Methods: We applied an optical tissue clearing (OTC) method, which uses ethyl cinnamate (ECi) as a fast, non-toxic and cheap clearing solvent, for 3D imaging of retrograde perfused lungs by laser confocal fluorescence microscopy and light sheet fluorescence microscopy. We also introduced expansion microscopy (ExM), a cutting-edge technique, in 3D imaging of lungs. We examined and compared the usefulness of these techniques for 3D lung imaging. The ExM protocol was further extended to paraffin-embedded lung metastases blocks. Results: The MHI148-PEI labeled lung vasculature was visualized by retrograde perfusion combined with trachea ligation and ECi based OTC. As compared with trans-cardiac perfusion, the retrograde perfusion results in a better maintenance of lung morphology. 3D structure of alveoli, vascular branches and cilia in lung were revealed by immunofluorescence staining after ExM. 3D distribution of microvasculature and neutrophil cells in 10 years old paraffin-embedded lung metastases were analyzed by ExM. Conclusions: The retrograde perfusion combined with trachea ligation technique could be applied in the lung research in mice. 3D structure of lung vasculature can be visualized by MHI148-PEI perfusion and ECi based OTC in an efficient way. ExM and immunofluorescence staining protocol is highly recommended to perform 3D imaging of fresh fixed lung as well as paraffin-embedded lung blocks. ; This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie Actions, grant agreement No 813839, Innovative Training Network RenalToolBox.