Search results for "electron microscopy"
showing 10 items of 706 documents
Dislocations in AIIIBVI single crystals
1988
High densities of planar defects are evidenced in various AIIIBVI layer compounds by systematic electron microscopy observations with the dark-field weak-beam image technique. Several samples are analyzed, as obtained from different crystal ingots of InSe grown by the Bridgman-Stockbarger method, and some GaS and GaSe single crystals grown both, from the melt and from the vapour. The observed defects are identified mainly as screw and edge dislocations, the orientation of which is obtained in some cases by the analysis of the Moire fringes. Dislocation densities ranging between 108 and 1010 cm−2 are measured, not uniformly distributed in the various regions of each sample. Finally, the obse…
Radiation damage in zircon
2003
A single, zoned, Sri Lankan zircon exhibits a range of microstructures from crystalline to nearly amorphous that are the result of radiation damage over a dose range of 2.1–10.1·1015 α-decay events/mg (0.16–0.47 dpa). The zones in the crystal were examined at a variety of length scales using optical microscopy, micro-Raman spectroscopy, electron microprobe analysis, and transmission electron microscopy. Birefringence varies linearly with dose: birefringence = −4.71·10−18 /g· D α + 4.86·10−2. Full width at half maximum (FWHM) measurements of the B1g(ν3) peak, as determined by micro-Raman spectroscopy, were used to estimate the extent of radiation damage in each zone. The radiation dose (calc…
Microstructural evolution of mullites produced from single-phase gels
2007
The crystalline microstructure of mullites obtained by heating monophasic gels has been investigated. Gels with alumina to silica molar ratio of 3:2 (as in secondary mullite) and 2:1 (as in primary mullite) were prepared by gelling mixtures of aluminium nitrate and tetraethylorthosilicate. Phase transformations were induced by heating the gel precursors, with different final treatment temperatures between 1173 and 1873 K. The mullites formed as a result of thermal treatment were studied by means of X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The crystalline structure (unit-cell parameters) and microstructure were determined from X-ray diffraction pa…
3D cryo-electron microscopy, molecular modelling and structural fitting with recombinant expressed virus like particles as part of drug design
2007
Extended abstract of a paper presented at MC 2007, 33rd DGE Conference in Saarbrücken, Germany, September 2 – September 7, 2007
Growth and defect studies of CdTe particles
2013
The paper reports the epitaxial growth of cadmium telluride (CdTe) particles by thermal deposition on cleaved planes of (001)NaCl and (001)KBr. Using high resolution transmission electron microscopy and electron diffraction it was shown that CdTe particles could have different orientation and phase (cubic or hexagonal) depending on the substrate temperature. Their most common defects are twins and stacking faults.
Quaternary structure and molecular model of a 4x6mer arthropod hemocyanin in oxygenated and deoxygenated states by 3D cryo-electron microscopy
2007
Extended abstract of a paper presented at MC 2007, 33rd DGE Conference in Saarbrücken, Germany, September 2 – September 7, 2007
Synchrotron Radiation-Based Micro-XANES and Micro-XRF Study of Unsuccessfully Produced Egyptian Blue from the Late Hellenistic Production Site of Kos…
2021
International audience; This paper examines the production technology of Egyptian blue, an ancient artificial pigment, through the investigation of an unsuccessfully produced pellet derived from the Hellenistic production site of Kos (Dodecanese, Greece). This heterogeneous material was investigated by a combination of laboratory and synchrotron radiation-based (SR) techniques: scanning electron microscopy coupled with energy-dispersive Xray spectrometry, micro-Raman spectroscopy, high-resolution SR micro-X-ray fluorescence spectroscopy, and SR micro-X-ray absorption near-edge structure spectroscopy (XANES), at the ID21 beamline of the European Synchrotron Radiation Facility. Principal comp…
Ultrastructural and histochemical analysis reveals ethylene-induced responses underlying reduced peel collapse in detached citrus fruit
2010
Fruits from many citrus cultivars develop depressed areas in the flavedo (outer part of the peel) and albedo (inner part) following detachment. Although ultrastructural analysis may provide important information about multiple plant responses to stresses and external stimuli at the cell and tissue levels, and despite the proved efficacy of ethylene in reducing peel damage in citrus fruit, cytological responses of this horticultural crop to protective ethylene concentrations have not yet been reported. We show that applying high ethylene levels (2 mu L L(-1) for 14 days) causes sublethal stress as it favored the alteration of cuticle, vacuole, middle lamella and primary wall, especially in t…
Loss of surface fibronectin after infection of cultured cells by HSV-1 and 2
1985
Fibronectin is lost from the surface of HSV infected cells during cell rounding. In order to investigate also the fate of fibronectin during the process of HSV-induced cell-fusion, BHK, Vero as well as primary or secondary rabbit kidney cells were infected with HSV-1 strains producing cell-fusion. By immunofluorescence and immunoelectron microscopy a considerable loss of fibronectin after HSV infection could be demonstrated leaving only irregular clumps of fibronectin containing virus particles on the cell surface. Decrease and disarrangement of fibronectin was similar during cell rounding and cell fusion. Loss of Fibronectin was closely connected with the two types of the cytopathic effect…