Search results for " scanning electron"
showing 10 items of 36 documents
Advanced microscopy analysis of the micro-nanoscale architecture of human menisci
2019
AbstractThe complex inhomogeneous architecture of the human meniscal tissue at the micro and nano scale in the absence of artefacts introduced by sample treatments has not yet been fully revealed. The knowledge of the internal structure organization is essential to understand the mechanical functionality of the meniscus and its relationship with the tissue’s complex structure. In this work, we investigated human meniscal tissue structure using up-to-date non-invasive imaging techniques, based on multiphoton fluorescence and quantitative second harmonic generation microscopy complemented with Environmental Scanning Electron Microscopy measurements. Observations on 50 meniscal samples extract…
Effects of Metal-Organic Chemical Vapour Deposition grown seed layer on the fabrication of well aligned ZnO nanorods by Chemical Bath Deposition
2011
Well aligned, long and uniform ZnO nanorods have been reproducibly fabricated adopting a two-steps Metal-Organic Chemical Vapour Deposition (MOCVD) and Chemical Bath Deposition (CBD) fabrication approaches. Thin (<100 nm) ZnO buffer layers have been seeded on silicon substrates by MOCVD and ZnO layers have been subsequently grown, in form of well textured nanorods, using CBD. It has been found that the structure and thickness of the seed layer strongly influence the final morphology and the crystal texturing of ZnO nanorods as well as the CBD growth rate. There is, in addition, a strong correlation between morphologies of CBD grown ZnO nanorods and those of the seed layer underneath. Thus, …
Effect of Hydrogen and Carbamide Peroxide in Bleaching, Enamel Morphology, and Mineral Composition: In vitro Study
2017
ABSTRACT Aim The aim of the study was to evaluate the bleaching effect, morphological changes, and variations in calcium (Ca) and phosphate (P) in the enamel with hydrogen peroxide (HP) and carbamide peroxide (CP) after the use of different application regimens. Materials and methods Four groups of five teeth were randomly assigned, according to the treatment protocol: HP 37.5% applied for 30 or 60 minutes (HP30, HP60), CP 16% applied for 14 or 28 hours (CP14, CP28). Changes in dental color were evaluated, according to the following formula: ΔE = [(La−Lb)2+(aa−ab)2 + (ba−bb)2]½. Enamel morphology and Ca and P compositions were evaluated by confocal laser scanning microscope and environmenta…
Effect of high power ultrasound on physical–chemical properties of polypropylene films aimed for food packaging: structure and surface features
2019
International audience; Biaxially oriented polypropylene (BOPP) coated with acrylic/polyvinylidene chloride (BOPPAcPVDC) and biaxially oriented coextruded polypropylene (BOPPcoex) films have been treated with high power ultrasound (HPUS) while submerged in water. Polymer structure and the surface morphology changes were noticed, and obtained results were correlated with the physical properties of tested materials. In anticipation of sonochemically enhanced reactions, physical–chemical profile of film samples was determined using thermogravimetric analysis, differential scanning calorimetry, Fourier-transform infrared spectroscopy, UV spectrophotometry and environmental scanning electron mic…
Optical characterization of Mg-doped GaN films grown by metalorganic chemical vapor phase deposition
2000
Scanning electron microscopy, micro-Raman, and photoluminescence (PL) measurements are reported for Mg-doped GaN films grown on (0001) sapphire substrates by low-pressure metalorganic chemical vapor phase deposition. The surface morphology, structural, and optical properties of GaN samples with Mg concentrations ranging from 1019 to 1021 cm−3 have been studied. In the scanning micrographs large triangular pyramids are observed, probably due to stacking fault formation and three-dimensional growth. The density and size of these structures increase with the amount of magnesium incorporated in the samples. In the photoluminescence spectra, intense lines were found at 3.36 and 3.31 eV on the tr…
Aroma behaviour during steam cooking within a potato starch-based model matrix.
2012
To help understand the organoleptic qualities of steam cooked foods, the kinetics of aroma release during cooking in a potato starch based model matrix was studied. Behaviour of components having a major impact in potato flavour were studied using solid phase micro extraction-gas chromatography (SPME-GC). Evolution of microstructure of potato starch model-matrix during steam cooking process was analyzed using environmental scanning electron microscopy (ESEM). Both aroma compounds that are naturally present in starch matrix and those that were added were analyzed. Both the aroma compounds naturally presented and those added had different behaviour depending on their physico-chemical properti…
Identification of Chinese fresh-water pearls using MN2+ activated cathodoluminescence
2000
Fresh-water tissue graft-cultured pearls from China were investigated using hot cathode and cold cathode cathodoluminescence microscopes. Supplementary investigations were done using X-radiography, a Scanning Electron Microscope, an optical microscope, and an Atomic Force Microscope (AFM). The results were compared with those of natural fresh-water pearls from the Mississippi river. Thin sections of fresh-water natural pearls from the Mississippi river could be distinguished from those of fresh-water tissue graft cultured pearls from China using a hot cathode cathodoluminescence microscope according to the distribution of Mn2+ as follows: (1) Fresh-water tissue graft cultured pearls from Ch…
Leaf epicuticular waxes effects egg parasitoid’s response to host adult footprint contact kairomone
2009
Chemical footprints left behind by true bugs are perceived as a contact kairomones by scelionid egg parasitoids. In the system Nezara viridula and its egg parasitoid Trissolcus basalis, previous studies have shown that the kairomone mediating such behavior is part of N. viridula’s cuticular hydrocarbons. In this study, the effect of epicuticular waxes of leaves of broad bean, Vicia faba, on wasp response to footprints of N. viridula females are investigated. Plants with intact waxes layer were used (1) without host chemical contamination, or (2) contaminated by host female footprints. Mechanically de-waxed plants were tested (3) without host chemical contamination, or (4) de-waxed a few min…
Microscopic findings and soil genetic “indicators” in support of pedoarchaeological studies
2015
Archaeologists use historical artefacts and archaeological records to reconstruct the communities that produced them and the environment in which they lived. Soil protects our buried or damaged heritage of archaeological and historic remains from depletion, damage, and any disturbance. Here are presented some preliminary results obtained in the framework of the FP7 Project "MEditerranean MOntainous LAndscapes: an historical approach to cultural Heritage based on traditional agrosystems (MEMOLA)" where ancient soils horizons are themselves archaeological records. In order to implement the MEMOLA archaeological study and to identify soil genetic "indicators", two integrated approaches were us…
Stigma morphology inAylosterasubg.Mediolobivia(Cactaceae) and its importance for systematic investigation
2013
The stigma of 31 taxa of Aylostera (Cactaceae) was studied using environmental scanning electron microscopy. Seven stigma types could be defined, based on the degree of fusion of the stigmatic lobes and, when these are completely separated (types I and II), their orientation. Four types (types IV, V, VI and VII) are present only in Aylostera subg. Mediolobivia, two of which (types IV and VII) are species-specific. Stigma morphology was found to be a good diagnostic character in Aylostera subg. Mediolobivia, allowing in some cases to distinguish species that had been confused previously. The stigmatic types here defined seem apt to characterize natural groups within the subgenus and are usef…