Search results for "TRANSMISSION ELECTRON"
showing 10 items of 426 documents
A highly selective, Hg2+ triggered hydrogelation: modulation of morphology by chemical stimuli
2014
We report the first Hg2+ selective hydrogelation by 4´-[4-(4- aminophenyl)phenyl]-2,2´:6´,2´´-terpyridine. The gel showed remarkable response towards specific chemical agents such as benzo-18-crown-6 ether and K+ which enabled extensive 10 modulation of the gel morphology. peerReviewed
Control of Morphology and Corona Composition in Aggregates of Mixtures of PS-b-PAA and PS-b-P4VP Diblock Copolymers: Effects of Solvent, Water Conten…
2014
The morphologies and corona compositions in aggregates of mixtures of PS-b-PAA and PS-b-P4VP diblock copolymers are influenced by controllable assembly parameters such as water content, block copolymer molar ratios, and solvent effects as well as the hydrophilic block lengths and block length ratios. All these factors can affect the morphology of the aggregates as well as their corona composition, the latter especially in vesicles, where two interfaces are involved. The morphologies and corona compositions of the aggregates were investigated by transmission electron microscopy and electrophoretic mobility, respectively. They depend, to a large extent, on the solubility of P4VP and PAA in th…
Control of Corona Composition and Morphology in Aggregates of Mixtures of PS-b-PAA and PS-b-P4VP Diblock Copolymers: Effects of pH and Block Length
2014
The corona compositions and morphologies in aggregates of mixtures of amphiphilic polystyrene-block-poly(acrylic acid) (PS-b-PAA) and polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP) diblock copolymers are influenced by controllable assembly parameters such as the hydrophilic block length and solution pH. The morphologies and corona compositions of the aggregates were investigated by transmission electron microscopy and electrophoretic mobility, respectively. When mineral acids or bases are present during aggregate formation, they can exert a strong influence on the corona composition. Morphology changes were also seen with changing pH, as well as changes in corona composition, specifica…
The Use of Electron Microscopy and Stereology in the Study of the Mammalian Pineal Gland
1983
Now that transmission electron microscopy (TEM) has been used for many years to study the pineal gland it is timely to evaluate what progress has been achieved by using this technique and to speculate which aspects of pineal research may benefit most by its application in the future.
Revealing lattice disorder, oxygen incorporation and pore formation in laser induced two-photon oxidized graphene
2019
Abstract Laser induced two-photon oxidation has proven to be a reliable method to pattern and control the level of oxidation of single layer graphene, which in turn allows the development of graphene-based electronic and optoelectronic devices with an all-optical method. Here we provide a full structural and chemical description of modifications of air-suspended graphene during the oxidation process. By using different laser irradiation doses, we were able to show via transmission electron microscopy, electron energy loss spectroscopy, electron diffraction and Raman spectroscopy how graphene develops from its pristine form up to a completely oxidized, porous and amorphous carbon layer. Furt…
Ni@Fe2O3 heterodimers: controlled synthesis and magnetically recyclable catalytic application for dehalogenation reactions
2012
Ni@Fe2O3 heterodimer nanoparticles (NPs) were synthesized by thermal decomposition of organometallic reactants. After functionalization, these Ni@Fe2O3 heterodimers became water soluble. The pristine heterodimeric NPs were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Mossbauer spectroscopy and magnetic susceptibility measurements. A special advantage of the heterodimers lies in the fact that nanodomains of different composition can be used as catalysts for the removal of environmentally hazardous halogenated pollutants.
Complexation of Uranium by Cells and S-Layer Sheets of Bacillus sphaericus JG-A12
2005
ABSTRACT Bacillus sphaericus JG-A12 is a natural isolate recovered from a uranium mining waste pile near the town of Johanngeorgenstadt in Saxony, Germany. The cells of this strain are enveloped by a highly ordered crystalline proteinaceous surface layer (S-layer) possessing an ability to bind uranium and other heavy metals. Purified and recrystallized S-layer proteins were shown to be phosphorylated by phosphoprotein-specific staining, inductive coupled plasma mass spectrometry analysis, and a colorimetric method. We used extended X-ray absorption fine-structure (EXAFS) spectroscopy to determine the structural parameters of the uranium complexes formed by purified and recrystallized S-laye…
Investigation of Activities for Pt-M Bimetallic Nanoparticles Catalysts on the Oxygen Reduction Reaction
2015
Bi-metallic Pt3Ni/C and Pt3Co/C electrocatalysts were successfully synthesized by a solvent free chemical vapour deposition method with a narrow particle size distribution. The results showed that the electrochemical surface area was increased by adding the additional Ni or Co to a pure Pt catalyst. Pt3Ni/C catalyst exhibited a significant enhancement of oxygen reduction reaction activity. The catalysts were characterized by EDS, XRD, HRTEM and electrochemical activity was determined using cyclic voltammetry.
Molybdenum blue: Binding to collagen fibres and microcrystal formation
2005
Collagen fibres have been shown by transmission electron microscopy to progressively bind the polyoxomolybdate ring-complex, termed molybdenum blue. Nucleation of cuboidal molybdenum blue microcrystals occurs on the surface of the collagen fibres, leading eventually to extensive coating of the fibres with microcrystals.
Silver-loaded nanoparticles affect ex-vivo mechanical behavior and mineralization of dentin
2019
Background: The aim was to evaluate the effect of silver loaded nanoparticles (NPs) application on the triboscopic, crystallographic and viscoelastic properties of demineralized dentin. Polymethylmetacrylate-based NPs and Ag loaded NPs were applied on demineralized dentin. Material and Methods: Treated and untreated surfaces were probed by a nanoindenter to test viscoelasticity, and by atomic force microscopy to test nanoroughness and collagen fibril diameter. X-ray diffraction and transmission electron microscopy through selected area diffraction and bright-field imaging were also used. Results: Dentin treated with Ag-NPs attained the lowest complex modulus, and the highest tan delta value…