Search results for "electron microscopy"
showing 10 items of 706 documents
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…
Soil microbial biomass carbon and fatty acid composition of earthworm Lumbricus rubellus after exposure to engineered nanoparticles
2014
none 6 no First Online: 14 October 2014 The aim of this work was to investigate the effect of engineered nanoparticles (NPs) on soil microbial biomass C (MBC) and on earthworm Lumbricus rubellus. An artificial soil was incubated for 4 weeks with earthworms fed with vegetable residues contaminated by NPs, consisting of Ag, Co, Ni and TiO2. After the treatments, soils were analysed for MBC and total and water soluble metal-NPs, whereas earthworms were purged for 28 days and then analysed for fatty acids (FAs) and total metal-NPs. Longitudinal sections of earthworms were investigated by environmental scanning electron microscopy (ESEM), equipped with energy-dispersive X-ray spectroscopy (EDS),…
Assembly of the Major and the Minor Capsid Protein of Human Papillomavirus Type 33 into Virus-like Particles and Tubular Structures in Insect Cells
1994
Native virions of human papillomaviruses (HPV) can be isolated from genital lesions only in very limited amounts. Recent studies have shown that virus-like particles can be obtained by expression of the capsid proteins using vaccinia virus recombinants or the baculovirus system. We now present the first detailed characterization of virus-like particles of a human papillomavirus associated with malignant genital lesions, HPV-33, produced in high yield using the baculovirus expression system. Assembly of the major capsid protein L1 alone or together with the minor capsid protein L2 has been obtained. Both spherical virus-like particles of 50-60 nm diameter and tubular structures of either 25-…
Unconventional Fluorescence Quenching in Naphthalimide-Capped CdSe/ZnS Nanoparticles
2013
Core–shell (CS) CdSe/ZnS quantum dots (QD) capped with ligands that possess a mercapto or an amino group and a naphthalimide (NI) as chromophore unit, linked by a short ethylene chain (CS@S–NI and CS@H2N–NI, respectively), have been synthesized and fully characterized by infrared and nuclear magnetic resonance spectroscopies, high-resolution transmission electron microscopy, and voltammetry as well as by steady-state absorption and emission spectroscopies. The organic ligands HS–NI and H2N–NI act as bidentate ligands, thereby causing a drastic decrease in the QD emission. This was particularly evident in the case of CS@S–NI. This behavior has been compared with that of commercially availabl…
Klimt artwork: red-pigment material investigation by backscattering Fe-57 Mössbauer spectroscopy, SEM and p-XRF
2017
Material tests were performed on a rediscovered Klimt-artwork "Trompetender Putto". We performed studies on the red colored spots, mainly taken from non-restored parts. MIMOS II Fe-57 Mossbauer spectroscopy (novelty in art-pigment analysis) mainly reveals haematite and crystallized goethite in red colors. Electron microscopy can identify various layers of the original and overpainting of an artwork. The number of layers fluctuates between three and four chemically painted areas. The portable X-ray fluorescence analysis enables to reduce the pigment list to containing mercury (cinnabar), lead, zinc, iron and titanium. Infrared-light-irradiation visualizes the different age of the pigments.
Multifunctional two-photon active silica-coated Au@MnO Janus particles for selective dual functionalization and imaging.
2014
Monodisperse multifunctional and nontoxic Au@MnO Janus particles with different sizes and morphologies were prepared by a seed-mediated nucleation and growth technique with precise control over domain sizes, surface functionalization, and dye labeling. The metal oxide domain could be coated selectively with a thin silica layer, leaving the metal domain untouched. In particular, size and morphology of the individual (metal and metal oxide) domains could be controlled by adjustment of the synthetic parameters. The SiO2 coating of the oxide domain allows biomolecule conjugation (e.g., antibodies, proteins) in a single step for converting the photoluminescent and superparamagnetic Janus nanopar…
Extracerebral biopsies in neurodegenerative diseases of childhood
1999
Abstract Among the numerous neurodegenerative diseases in children few may allow morphological diagnosis by extracerebral biopsy. These encompass neurometabolic conditions, foremost lysosomal disorders, but also peroxisomal and mitochondrial diseases marked by disease- or group-specific organelles. Largely, these neurometabolic conditions can also be diagnosed by biochemical and increasingly by molecular genetic techniques. However, there are a few neurodegenerative diseases which do not allow either biochemical or molecular genetic diagnosis and, thus, rely on biopsy of extracerebral tissues, so-called ‘essential’ biopsies to achieve a diagnosis during the patient's life. Among these few d…
Characterization of a new natural fiber from Arundo donax L. as potential reinforcement of polymer composites.
2013
Abstract The aim of this paper is to study the possibility of using of Arundo donax L. fibers as reinforcement in polymer composites. The fibers are extracted from the outer part of the stem of the plant, which widely grows in Mediterranean area and is diffused all around the world. To use these lignocellulosic fibers as reinforcement in polymer composites, it is necessary to investigate their microstructure, chemical composition and mechanical properties. Therefore, the morphology of A. donax L. fibers was investigated through electron microscopy, the thermal behavior through thermogravimetric analysis and the real density through a helium pycnometer. The chemical composition of the natura…
Synthesis of MoO3 Nanostructures and Their Facile Conversion to MoS2 Fullerenes and Nanotubes.
2007
The fast thermolysis of ammonium molybdate leads to a mixture of MoO3 and Mo5.3O14.5(OH)2.8(H2O)1.36 with spherical and rod-like morphologies. The oxide mixture can be converted in quantitative yield to inorganic fullerene-type (IF) MoS2 and MoS2 nanotubes (NT) by H2S reduction using a facile and quick procedure. The products were studied by X-Ray Diffraction (XRD) and by Transmission Electron Microscopy (TEM). TEM analysis reveals that the spherical and rod-like morphology of the oxide precursor is preserved during the H2S treatment.
Structural properties of GaN quantum dots
2006
The strain state and the deformation profile of GaN quantum dots embedded in AlN have been measured by high resolution electron microscopy, medium energy ion scattering and grazing incidence X-ray diffraction. The results are compared with theoretical calculations, allowing one to conclude that GaN quantum dots experience a non biaxial strain which drastically decreases when going from the basal plane up to the apex of the dots. We also demonstrate that AlN is distorted in the surroundings of the dots, which provides the driving force for vertical correlation of GaN dots when the AlN spacer between successive planes is thin enough.