Search results for " Microscopy"

Microscopic investigations of homogeneous nucleation in charged sphere suspensions.

2005

We studied the homogeneous nucleation kinetics of an aqueous suspension of charged colloidal spheres under de-ionized conditions. Samples of equilibrium crystalline structure were shear molten and the metastable melt left to solidify after cessation of shear. At low particle number densities n, corresponding to low metastability of the melt, nucleation was monitored directly via video microscopy. We determined the nucleation rates gamma(t) by counting the number of newly appearing crystals in the observation volume per unit time. Using a suitable discrete adaptation of Avrami's [J. Chem. Phys. 7, 1003 (1939); ibid.8, 212 (1940); ibid.9, 177 (1941)] model for solidification via homogeneous n…

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…

Microchemical surface analysis of historic copper-based coins by the combined use of FIB-FESEM-EDX, OM, FTIR spectroscopy and solid-state electrochem…

2019

[EN] A multi-technique strategy, including microscopy, spectroscopic and electrochemical techniques, is proposed to study thin corrosion layers that form on the surface of historic copper-based coins. An accurate characterisation of this external corrosion layer is important for selecting a suitable conservation and/or restoration treatment. For this purpose, a series of copper-based coins from different historical periods and provenances, which mainly exhibited atmospheric corrosion, was analysed. The morphology of the corrosion layer and the upper core of coins was studied in trenches done on coin surfaces with a focused ion beam gun, coupled to a field emission scanning electron microsco…

Nanowire iron(III) coordination polymer based on 1,2,4-triazolo[1,5-a]pyrimidine and chloride ligands

2019

Abstract The neutral ligand 1,2,4-triazolo[1,5-a]pyrimidine (tp) has been employed to prepare a new coordination compound of Fe(III), [FeCl3(tp)2]n (1). Compound 1 was investigated by single crystal X-ray diffraction and found to be a coordination polymer forming a ladder structure based on metal–ligand interactions, while H-bonding and aromatic interactions contribute to the supramolecular self-assembly into a 3D nanostructured material. The polymeric assembly is retained also in solution, where a metallo-supramolecular polymer based on coordinative metal–ligand binding is present, as shown by dynamic light scattering (DLS) measurements. The redox properties of the Fe(III) coordination pol…

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…

Light and electron microscopy study of D2-40 expression on lymphatics

2008

Structure and Deformations of Pd−Ni Core−Shell Nanoparticles

2005

International audience; Homogeneous collections of Pd−Ni core−shell nanoparticles have been prepared by decomposition of metal−organic compounds and studied by several electron microscopy techniques: transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), high-resolution transmission electron microscopy (HRTEM), energy-filtered microscopy (EFTEM), and by X-ray photoelectron spectroscopy (XPS). The physical and chemical properties of the Pd shell are supposed to depend on its electronic properties, which are influenced by the presence of the Ni core and by the deformation in the Pd lattice. Here, the interfacial structure of Pd/Ni and the lattice deformations in t…

Single molecule localization microscopy of the distribution of chromatin using Hoechst and DAPI fluorescent probes.

2014

Several approaches have been described to fluorescently label and image DNA and chromatin in situ on the single-molecule level. These superresolution microscopy techniques are based on detecting optically isolated, fluorescently tagged anti-histone antibodies, fluorescently labeled DNA precursor analogs, or fluorescent dyes bound to DNA. Presently they suffer from various drawbacks such as low labeling efficiency or interference with DNA structure. In this report, we demonstrate that DNA minor groove binding dyes, such as Hoechst 33258, Hoechst 33342, and DAPI, can be effectively employed in single molecule localization microscopy (SMLM) with high optical and structural resolution. Upon ill…