Transmission Electron Microscopy, diffraction and electron probe X-Ray microanalysis of senile scleral plaques of the eye

1986 ◽  
Vol 44 ◽  
pp. 320-321
Author(s):  
A. J. Tousimis
Keyword(s):  
Electron Microscopy ◽  
Electron Probe ◽  
Calcium Sulfate ◽  
Wave Length ◽  
Light And Electron Microscopy ◽  
Rectus Muscle ◽  
X Ray ◽  
Lateral Rectus Muscle ◽  
Transmission Electron ◽  
Tissue Calcium

Scleral plaques of the human eye are small, oval, grayish lesions located 1 to 2 mm in front of the insertion of the lateral rectus muscle. They are common in individuals over 50. Roper's review attributes them to "dehydration, sclerosis, and hyalinization of the connective tissue." Calcium carbonate was reported by Klein-Moncrieff and calcium sulfate and apatite mixed with gypsum by Cogan et al. In the present study light and electron microscopy along with electron diffraction and electron probe x-ray microanalysis (both wave length and energy dispersive) were used to examine the morphology and elemental composition of 12 eyes with the majority of them with unilateral and some bilateral plaques.

scholarly journals The Influence of A Mo Addition on the Interfacial Morphologies and Corrosion Resistances of Novel Fe-Cr-B Alloys Immersed in Molten Aluminum

Materials ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 256 ◽  
Author(s):  
Zicheng Ling ◽  
Weiping Chen ◽  
Weiye Xu ◽  
Xianman Zhang ◽  
Tiwen Lu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Electron Probe ◽  
Molten Aluminum ◽  
Dendritic Structure ◽  
H13 Steel ◽  
X Ray ◽  
Transmission Electron ◽  
The Matrix ◽  
Scanning Electron

The influence of a Mo addition on the interfacial morphologies and corrosion resistances of novel Fe-Cr-B alloys in molten aluminum at 750 °C was systematically investigated using scanning electron microscopy, X-ray diffractometer, electron probe microanalysis, and transmission electron microscopy. The results indicated that Mo could not only strengthen the matrix but also facilitate the formation of borides. Furthermore, the microstructures of Mo-rich M2B boride changed from a local eutectic net-like structure to a typical coarse dendritic structure and a blocky hypereutectic structure with increasing Mo addition. This was true of the blocky Mo-rich M2B boride, rod-like Cr-rich M2B boride and the corrosion products, which had a synergistic effect on retarding of the diffusion of molten aluminum. Notably, the corrosion resistance of the Fe-Cr-B-Mo alloy, with an 8.3 wt.% Mo addition, was 3.8 times higher than that of H13 steel.

scholarly journals The osmium tetroxide-p-phenylenediamine procedure reveals the chromatid cores and kinetochores of meiotic chromosomes by light and electron microscopy.

1996 ◽  
Vol 44 (11) ◽  
pp. 1279-1288 ◽  
Author(s):  
C Antonio ◽  
J M González-García ◽  
J Page ◽  
J A Suja ◽  
J C Stockert ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Reaction Mechanism ◽  
Osmium Tetroxide ◽  
Light And Electron Microscopy ◽  
X Ray ◽  
Meiotic Chromosomes ◽  
Transmission Electron ◽  
Ethanol Acetic Acid ◽  
Electron Imaging ◽  
Z Contrast

We analyzed first-metaphase meiotic chromosomes of the grasshopper Chorthippus jucundus by two different methods, i.e., a silver impregnation technique and the osmium tetroxide-p-phenylenediamine (Os-PPD) procedure. The former was applied on squashed testes previously fixed in ethanol-acetic acid, whereas for Os-PPD the material was not subjected to any previous extraction treatment but was fixed in OsO4, treated with PPD, and embedded in Epon 812. Both techniques revealed chromatid cores and kinetochores regardless of the processing of the material (squashed or sectioned). Unstained Os-PPD sections were analyzed by light microscopy and transmission electron microscopy (TEM). The Os-PPD technique provided a high contrast of chromatid cores and kinetochores in relation to the chromatin, which revealed a low electron density. To determine the Os-PPD reaction mechanism, the PAS procedure, as well as scanning electron microscopy (SEM) backscattering and SEM X-ray microanalysis, was performed on sections. By use of the Os-PPD-PAS procedure, glycol groups formed by oxidation of osmium bound to aromatic substrates were detected in chromatid cores and kinetochores by brightfield and fluorescence microscopy. A high Z contrast was detected in these structures by backscattered electron imaging. SEM X-ray microanalysis showed osmium and phosphorus to be the main elements present on the chromatid cores. Taking into account the known reactivity of OsO4 and the present results, the possible participation of nucleic acids as well as proteins in the Os-PPD reaction mechanism and in the composition of chromatid cores and kinetochores is discussed.

Estimation of Interdiffusivities of the Pseudo NiAl Binary Phase Formed in a Nickel-based Superalloy by Pack Cementation

2005 ◽  
Vol 20 (9) ◽  
pp. 2340-2347 ◽  
Author(s):  
H. Wei ◽  
X.F. Sun ◽  
Q. Zheng ◽  
H.R. Guan ◽  
Z.Q. Hu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Electron Probe ◽  
Pack Cementation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Binary Phase ◽  
Nickel Based Superalloy ◽  
Transmission Electron ◽  
Scanning Electron

The pseudo NiAl binary phase was formed in a nickel-based superalloy by pack cementation. Scanning electron microscopy, transmission electron microscopy, x-ray diffraction, electron probe microanalysis, and positron annihilation technique were used to characterize the pseudo NiAl binary phase. Based on reasonable assumptions, the chemical interdiffusivities of the pseudo NiAl binary phase were then assessed by means of the modified Wagner’s method. The results showed that the chemical interdiffusivities of the pseudo NiAl binary phase were about two orders of magnitude lower than those reported by others. The analysis indicated that the change in thermodynamic properties due to the additions of the microalloying atoms originally present in a superalloy could be responsible mainly for a decrease in chemical interdiffusivities.

Combined Plasma-Microincineration, Electron Microscopy And Electron Probe Microanalysis For Fine Localization of Biological Mineral Substances

1973 ◽  
Vol 31 ◽  
pp. 334-335 ◽  
Author(s):  
Richard S. Thomas ◽  
Mabel I. Corlett
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Electron Probe ◽  
Oxygen Plasma ◽  
Chemical Nature ◽  
The Other ◽  
X Ray ◽  
Transmission Electron ◽  
Mineral Substances ◽  
Fine Localization

Ash patterns produced by oxygen plasma microincineration(OPM) of thin-sectioned biological materials and examined with the transmission electron microscope (TEM) can show unambiguously the distribution of mineral substances in the specimen with resolutions down to 100 Å. The chemical nature of the mineral is not demonstrated, however. Electron-probe X-ray microanalysis (EXM), on the other hand, can determine precisely the nature of the mineral in ashgd or unashed sections but its spatial resolution is limited to 1000-10,000 A at best. Also its sensitivity of analysis on unashed specimens is limited by intolerance of the specimen to high beam intensities. Using both TEM and EXM together on ash patterns of suitable specimens can overcome their independent spatial and chemical limitations. Furthermore, use of OPM produces a highly stable mineral specimen for EXM, thereby improving sensitivity.

Distribution de quelques oligo-éléments dans des cristaux de graines de Raphanus

1985 ◽  
Vol 63 (12) ◽  
pp. 2399-2407 ◽  
Author(s):  
Louis Genevès ◽  
Jacques Rutin ◽  
Sylvain Halpern
Keyword(s):  
Electron Probe Microanalysis ◽  
Raphanus Sativus ◽  
Electron Probe ◽  
Wave Length ◽  
X Ray ◽  
Transmission Electron ◽  
Small Crystals ◽  
Raphanus Sativus L ◽  
Ultrathin Sections ◽  
Micro Elements

Globoid crystals were studied in the cotyledonary parenchyma of anhydrous seeds of radish (Raphanus sativus L., Brassicaceae) in ultrathin sections after aldehydic fixation. Crystals derived from the same seeds were also isolated, by print techniques without fixation or aqueous phase. Eleven elements (Mg, Al, Si, P, S, K, Ca, Mn, Fe, Cu, Zn) were looked for using transmission electron probe microanalysis and a wave length dispersive X-ray spectrometry (Camebax microprobe). Crystals of various sizes, rich in P, Mg, and Ca, could contain some micro-elements (Mn, Fe, Zn … ) which could be included in the phytine. Other small crystals, stable under radiation and rich in Fe, were low in P. These two sorts were characterized in globoids, in sections and in prints. Other crystals, isolated from dry seeds, rich in Ca, K, and Mg, were poor in P. Finally, long or angular very stable crystals, rich in Al, lacking P, and hence without phytine, could contain other metals (Fe, Cu, Zn … ) which could be included in nonphytinic molecules. A given metal (Fe or Mn … ) can be found in several types of crystals. Several groups of crystals with similar characters (morphology, composition) were defined, either in protein bodies, in ultrathin sections, or in prints.

Laboratory-Based Cryogenic Soft X-Ray Tomography with Correlative Cryo-Light and Electron Microscopy

2013 ◽  
Vol 19 (1) ◽  
pp. 22-29 ◽  
Author(s):  
David B. Carlson ◽  
Jeff Gelb ◽  
Vadim Palshin ◽  
James E. Evans
Keyword(s):  
Electron Microscopy ◽  
Light And Electron Microscopy ◽  
Three Dimensional ◽  
Test Sample ◽  
X Ray ◽  
Whole Cells ◽  
Correlative Imaging ◽  
Transmission Electron ◽  
Cumulative Radiation Dose ◽  
Fluorescence Light

AbstractHere we present a novel laboratory-based cryogenic soft X-ray microscope for whole cell tomography of frozen hydrated samples. We demonstrate the capabilities of this compact cryogenic microscope by visualizing internal subcellular structures of Saccharomyces cerevisiae cells. The microscope is shown to achieve better than 50 nm half-pitch spatial resolution with a Siemens star test sample. For whole biological cells, the microscope can image specimens up to 5 μm thick. Structures as small as 90 nm can be detected in tomographic reconstructions following a low cumulative radiation dose of only 7.2 MGy. Furthermore, the design of the specimen chamber utilizes a standard sample support that permits multimodal correlative imaging of the exact same unstained yeast cell via cryo-fluorescence light microscopy, cryo-soft X-ray microscopy, and cryo-transmission electron microscopy. This completely laboratory-based cryogenic soft X-ray microscope will enable greater access to three-dimensional ultrastructure determination of biological whole cells without chemical fixation or physical sectioning.

Structure, Composition and Superconductivity of High Tc Tl–Ba–Ca–Cu–O System

1989 ◽  
Vol 156 ◽  
Author(s):  
Yasuhiko Syono ◽  
Masae Kikuchi ◽  
Satoru Nakajima ◽  
Teruo Suzuki ◽  
Takeo Oku ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Electron Probe ◽  
Magnetic Measurements ◽  
Chemical Compositions ◽  
Superconducting Properties ◽  
High Tc Superconductors ◽  
Critical Temperatures ◽  
High Tc ◽  
X Ray ◽  
Transmission Electron

ABSTRACTBulk high Tc superconductors of Tl2Ba2Can−1CunO2n+4 (n=1−4) and TlBa2Can−1CunO2n+3 (n=2−5) were synthesized, and their structures, chemical compositions and superconducting properties were studied by means of X-ray powder diffraction, electron probe microanalysis, transmission electron microscopy, and electrical and magnetic measurements. Superconducting critical temperatures are discussed in terms of average Cu valence and Cu-O bond length within the plane which vary with the number of Cu layers.

Nano-scale Interfacial Reactions of SrRuO3 Thin Film on Si (100) Substrate

2001 ◽  
Vol 666 ◽  
Author(s):  
Sang Ho Oh ◽  
Chan-Gyung Park
Keyword(s):  
Thin Film ◽  
Electron Microscopy ◽  
Electron Probe ◽  
Interfacial Reactions ◽  
Si Substrate ◽  
Structural Variations ◽  
X Ray ◽  
Binary Oxides ◽  
Transmission Electron ◽  
Srruo3 Thin Film

ABSTRACTInterfacial reactions between SrRuO3 films and Si substrate were investigated by using field emission-transmission electron microscopy (FE-TEM). The compositional and structural variations across the interface were analyzed by using energy dispersive X-ray spectroscopy (EDS) and diffraction with an electron probe in 0.5 nm in diameter. Two constituent binary oxides of SrRuO3, i.e. SrO and RuO2, were found to react differently on Si surface: 1) SrO in stable contact with Si, and 2) RuO2 in unstable contact. The reduction of SrRuO3 to elemental Ru by Si is believed to be most favorable candidate for the reaction leading to the unstable contact of SrRuO3 on Si.

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