scholarly journals Cathodoluminescence, Raman and scanning electron microscopy with energy dispersion system mapping to unravel the mineralogy and texture of an altered CaAl‐rich inclusion in Renazzo CR2 carbonaceous chondrite

Author(s):  
Mario Tribaudino ◽  
Danilo Bersani ◽  
Luciana Mantovani ◽  
Mattia Pizzati ◽  
Giancarlo Salviati
2019 ◽  
Vol 9 (14) ◽  
pp. 2837 ◽  
Author(s):  
Antonio Scarano ◽  
Sammy Noumbissi ◽  
Saurabh Gupta ◽  
Francesco Inchingolo ◽  
Pierbiagio Stilla ◽  
...  

Background: Drills are an indispensable tool for dental implant surgery. Today, there are ceramic zirconium dioxide and metal alloy drills available. Osteotomy drills are critical instruments since they come in contact with blood and saliva. Furthermore, they are reusable and should be cleaned and sterilized between uses. Depending on the material, sterilizing agents and protocols can alter the surface and sharpness of implant drills. The hypothesis is that cleaning and sterilization procedures can affect the surface structure of the drills and consequently reduce their cutting efficiency. Methods: Eighteen zirconia ceramic drills and eighteen metal alloy drills were evaluated. Within the scope of this study, the drills were not used to prepare implant sites. They were immersed for 10 min in human blood taken from volunteer subjects and then separately exposed to 50 cycles of cleansing with 6% hydrogen peroxide, cold sterilization with glutaraldehyde 2%, and autoclave heat sterilization. Scanning Electron Microscopy (SEM) and energy dispersion X-ray (EDX) microanalysis were conducted before and after each cycle and was used to evaluate the drill surfaces for alterations. Results: After exposure to the cleansing agents used in this study, alterations were seen in the steel drills compared to zirconia. Conclusions: The chemical sterilization products used in this study cause corrosion of the metal drills and reduce their sharpness. It was observed that the cycles of steam sterilization did not affect any of the drills. Zirconia drill surfaces remained stable.


Author(s):  
Sergey Leonov

Abstract. The article is devoted to the possibilities of innovative research methods in forensic medicine-scanning electron microscopy with energy-dispersion analysis. The described methods were used in conducting experimental studies in the case of a gunshot retrograde injury. Aim. The purpose of the work was to study the particles formed during the destruction of a semi-shell shell and an obstacle (triplex car glass) when fired from a hunting Saiga carbine with 5. 45x39 cartridges. Material and methods. Car triplex windshields from BMW and Mercedes-Benz cars were used as a barrier. The shots were fired from a hunting Saiga carbine with a 5.45x39 cartridge. The shots were fired from a distance of 10 m. As targets, white calico with dimensions of 100x150 cm was used, stretched on a wooden frame, or fixed on a chipboard. The distance between the target and the barrier was 100 cm, which roughly corresponded to the distance from the windshield of the car to the driver and the passenger in the front seat. The studies were carried out using the SEM "Hitachi FlexSem1000 II" and the energy-dispersive X-ray spectrometer "Bruker Quantax 80". Results. As a result of the conducted research with the help of microscopy, the presence of 7 types of foreign bodies on the surface of the target was established, which are the products of the destruction of the fire projectile and the barrier: glass fragments; glass fragments; crumbly deposition of glass particles; glass fragments caked with the metal of the projectile; fragments of the projectile; spherical metal particles; overlays of molten metal in the form of puddles. With the help of energy dispersion analysis, it was possible to determine the elemental composition of the particles of the barrier, the fire shell, and to identify the overlap of the target particles. Conclusion. As a result of the experimental study, it was found that the use of SEM and EDS analysis significantly increases the effectiveness and evidence-based expert research in solving the problems of causing damage through the barrier-the windscreen of modern cars. Key words: scanning electron microscopy, gunshot trauma, energy dispersion analysis, fragments of the barrier.


Author(s):  
P.S. Porter ◽  
T. Aoyagi ◽  
R. Matta

Using standard techniques of scanning electron microscopy (SEM), over 1000 human hair defects have been studied. In several of the defects, the pathogenesis of the abnormality has been clarified using these techniques. It is the purpose of this paper to present several distinct morphologic abnormalities of hair and to discuss their pathogenesis as elucidated through techniques of scanning electron microscopy.


Author(s):  
P.J. Dailey

The structure of insect salivary glands has been extensively investigated during the past decade; however, none have attempted scanning electron microscopy (SEM) in ultrastructural examinations of these secretory organs. This study correlates fine structure by means of SEM cryofractography with that of thin-sectioned epoxy embedded material observed by means of transmission electron microscopy (TEM).Salivary glands of Gromphadorhina portentosa were excised and immediately submerged in cold (4°C) paraformaldehyde-glutaraldehyde fixative1 for 2 hr, washed and post-fixed in 1 per cent 0s04 in phosphosphate buffer (4°C for 2 hr). After ethanolic dehydration half of the samples were embedded in Epon 812 for TEM and half cryofractured and subsequently critical point dried for SEM. Dried specimens were mounted on aluminum stubs and coated with approximately 150 Å of gold in a cold sputtering apparatus.Figure 1 shows a cryofractured plane through a salivary acinus revealing topographical relief of secretory vesicles.


Author(s):  
Nakazo Watari ◽  
Yasuaki Hotta ◽  
Yoshio Mabuchi

It is very useful if we can observe the identical cell elements within the same sections by light microscopy (LM), transmission electron microscopy (TEM) and/or scanning electron microscopy (SEM) sequentially, because, the cell fine structure can not be indicated by LM, while the color is; on the other hand, the cell fine structure can be very easily observed by EM, although its color properties may not. However, there is one problem in that LM requires thick sections of over 1 μm, while EM needs very thin sections of under 100 nm. Recently, we have developed a new method to observe the same cell elements within the same plastic sections using both light and transmission (conventional or high-voltage) electron microscopes.In this paper, we have developed two new observation methods for the identical cell elements within the same sections, both plastic-embedded and paraffin-embedded, using light microscopy, transmission electron microscopy and/or scanning electron microscopy (Fig. 1).


Author(s):  
Ronald H. Bradley ◽  
R. S. Berk ◽  
L. D. Hazlett

The nude mouse is a hairless mutant (homozygous for the mutation nude, nu/nu), which is born lacking a thymus and possesses a severe defect in cellular immunity. Spontaneous unilateral cataractous lesions were noted (during ocular examination using a stereomicroscope at 40X) in 14 of a series of 60 animals (20%). This transmission and scanning microscopic study characterizes the morphology of this cataract and contrasts these data with normal nude mouse lens.All animals were sacrificed by an ether overdose. Eyes were enucleated and immersed in a mixed fixative (1% osmium tetroxide and 6% glutaraldehyde in Sorenson's phosphate buffer pH 7.4 at 0-4°C) for 3 hours, dehydrated in graded ethanols and embedded in Epon-Araldite for transmission microscopy. Specimens for scanning electron microscopy were fixed similarly, dehydrated in graded ethanols, then to graded changes of Freon 113 and ethanol to 100% Freon 113 and critically point dried in a Bomar critical point dryer using Freon 13 as the transition fluid.


Sign in / Sign up

Export Citation Format

Share Document