Sporogenesis and septum schizolysis in Dipodascus aggregates

1989 ◽  
Vol 67 (7) ◽  
pp. 2150-2153 ◽  
Author(s):  
A. Tsuneda ◽  
S. Murakami
Keyword(s):  
Electron Microscopy ◽  
Freeze Drying ◽  
The Other ◽  
Cross Wall

Asci, ascospores, and arthroconidia of Dipodascus aggregatus were examined by electron microscopy. Freeze-drying of mature asci caused rupture of the ascal walls and made it possible to observe capsulated ascospores in situ. Two types of septa occurred: (i) one having a remarkably thickened cross wall which protruded to form a circumferential ridge on the hyphae, and (ii) the other without such a bulging ridge. Schizolysis of these septa resulted in the formation of morphologically distinct arthroconidia. The scizolytic process of the ridged septa was demonstrated in detail. There was no evidence to support that the plasmadesmal canals in the septa function as disjunctive pegs in the process of arthroconidial separation.

A Differential Scanning Calorimetric Study of Carbide Transition in 10Cr Tempered Martensitic Steels

2015 ◽  
Vol 1754 ◽  
pp. 37-42
Author(s):  
H.C. Wang
Keyword(s):  
Electron Microscopy ◽  
Carbide Precipitation ◽  
The Other ◽  
Differential Scanning Calorimetric ◽  
Calorimetric Study ◽  
Martensitic Steels ◽  
Scanning Calorimetry ◽  
Precise Understanding ◽  
Kinetics Of

ABSTRACTThe process and kinetics of carbide precipitation upon tempering of an Fe-10Cr-0.15C (wt.%) alloy fabricated from high-purity components has been studied. Differential scanning calorimetry reveals three exotherms in a temperature range of 100-700°C. Using advanced electron microscopy and Kissinger analysis, the exothermic processes have been interpreted. Cementite precipitated first upon tempering at temperatures as low as 200°C; M7C3 and M23C6 appear at higher temperatures, precipitating at approximately the same time but on different sites (M7C3 within grains and laths and M23C6 on grain and lath boundaries). Subsequently, the more stable M23C6 coarsens at the expense of M7C3, which dissolves. The first exotherm was interpreted as being related to the precipitation of cementite whilst the other two overlapping exotherms were interpreted as relating to the concurrent precipitation and coarsening of M7C3 and M23C6, respectively. In-situ SEM and TEM observation is being conducted in order to obtain a more precise understanding and further validate the interpretation of the DSC results.

scholarly journals Carboxylic acids: effective inhibitors for calcium sulfate precipitation?

2014 ◽  
Vol 78 (6) ◽  
pp. 1465-1472 ◽  
Author(s):  
Taher Rabizadeh ◽  
Caroline L. Peacock ◽  
Liane G. Benning
Keyword(s):  
Electron Microscopy ◽  
Carboxylic Acids ◽  
Calcium Sulfate ◽  
Mineralogical Composition ◽  
The Other ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron ◽  
Better Than

Results are reported here of an investigation into the effects of three carboxylic acid additives (tartaric, maleic and citric acids) on the precipitation of calcium sulfate phases. Precipitation reactions were followed at pH 7 in the pure CaSO4 system and in experiments with 0–20 ppm carboxylic acids added using in situ UV-VIS spectrophotometry (turbidity). The solid products were characterized in terms of their mineralogical composition, using X-ray diffraction, during and at the end of each reaction, and in terms of their morphological features, by scanning electron microscopy. All additives increased the time needed for turbidity to develop (induction time, start of precipitation) and the comparison between additive and additive-free experiments showed that, at equivalent concentrations, citric acid performed far better than the other two carboxylic acids. In all cases bassanite precipitated first and with time it transformed to gypsum. The addition of citrate stabilized bassanite and changed the final gypsum habit from typical needle-like crystals in the pure CaSO4 system to plates in the citrate-additive experiments.

scholarly journals In Situ Heating Transmission Electron Microscopy Observation of Nanoeutectic Lamellar Structure in Sn–Ag–Cu Alloy on Au Under-Bump Metallization

2013 ◽  
Vol 19 (S5) ◽  
pp. 49-53 ◽  
Author(s):  
Jong-Hyun Seo ◽  
Sang-Won Yoon ◽  
Kyou-Hyun Kim ◽  
Hye-Jung Chang ◽  
Kon-Bae Lee ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Interface Energy ◽  
The Other ◽  
Lamella Spacing ◽  
Cu Alloy ◽  
Transmission Electron ◽  
Two Phases ◽  
Bond Pads

AbstractWe investigated the microstructural evolution of Sn96.4Ag2.8Cu0.8 solder through in situ heating transmission electron microscopy observations. As-soldered bump consisted of seven layers, containing the nanoeutectic lamella structure of AuSn and Au5Sn phases, and the polygonal grains of AuSn2 and AuSn4, on Au-plated Cu bond pads. Here, we found that there are two nanoeutectic lamellar layers with lamella spacing of 40 and 250 nm. By in situ heating above 140°C, the nanoeutectic lamella of AuSn and Au5Sn was decomposed with structural degradation by sphering and coarsening processes of the lamellar interface. At the third layer neighboring to the lamella layer, on the other hand, Au5Sn particles with a zig-zag shape in AuSn matrix became spherical and were finally dissipated in order to minimize the interface energy between two phases. In the other layers except both lamella layers, polycrystal grains of AuSn2 and AuSn4 grew by normal grain growth during in situ heating. The high interface energy of nanoeutectic lamella and polygonal nanograins, which are formed by rapid solidification, acted as a principal driving force on the microstructural change during the in situ heating.

Archaeological Fingerprinting and Fremont Figurines

2013 ◽  
Vol 1 (1) ◽  
pp. 3-12 ◽  
Author(s):  
Bonnie L. Pitblado ◽  
Molly Boeka Cannon ◽  
Megan Bloxham ◽  
Joel Janetski ◽  
J.M. Adovasio ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Research Team ◽  
The Other ◽  
X Ray ◽  
Cultural Ideology ◽  
Destructive Methods ◽  
Scanning Electron ◽  
Portable Art

AbstractAfter the anonymous 2011 return of a long-missing Pilling Fremont figurine, a multi-disciplinary research team conducted “fingerprint” analyses in an effort to match it to 10 mates with intact provenance. The Pilling figurines, crafted 1,000 years ago and cached in a remote sandstone niche in eastern Utah, are the most significant find of Fremont portable art ever documented because they occurred in situ and are unparalleled in detail and completeness. Most of the other 400-plus known Fremont figurines derive from secondary contexts, limiting inferences archaeologists might otherwise draw in domains ranging from Fremont exchange to inter- and intra-cultural ideology. Basketry-imprint analysis, scanning electron microscopy, and portable X-ray fluorescence suggest that the returned specimen is the original Pilling. After a 40-year absence, it is now permanently curated with the rest of the collection at the Prehistoric Museum, USU Eastern, in Price, Utah, and can contribute to research of a rare artifact class. The techniques reported can also be applied to finds of fragmentary Fremont figurines in secondary contexts to assess relationships among specimens and sites. Most broadly, the successful application of nondestructive pXRF may inspire confidence in scientists studying rare and delicate specimens traditionally profiled using destructive methods such as INAA.

The Critical Point Drying Method Applied to Scanning Electron Microscopy of L-929 Cells

1970 ◽  
Vol 28 ◽  
pp. 278-279
Author(s):  
Charles TurnbiLL ◽  
Delbert E. Philpott
Keyword(s):  
Electron Microscopy ◽  
Carbon Dioxide ◽  
Surface Tension ◽  
Critical Point ◽  
Freeze Drying ◽  
Attractive Alternative ◽  
Crystal Formation ◽  
Critical Point Drying ◽  
Time Required ◽  
Scanning Electron

The advent of the scanning electron microscope (SCEM) has renewed interest in preparing specimens by avoiding the forces of surface tension. The present method of freeze drying by Boyde and Barger (1969) and Small and Marszalek (1969) does prevent surface tension but ice crystal formation and time required for pumping out the specimen to dryness has discouraged us. We believe an attractive alternative to freeze drying is the critical point method originated by Anderson (1951; for electron microscopy. He avoided surface tension effects during drying by first exchanging the specimen water with alcohol, amy L acetate and then with carbon dioxide. He then selected a specific temperature (36.5°C) and pressure (72 Atm.) at which carbon dioxide would pass from the liquid to the gaseous phase without the effect of surface tension This combination of temperature and, pressure is known as the "critical point" of the Liquid.

Immunocytochemistry. A Review of Methodology for Electron Microscopic Applicaiton

1974 ◽  
Vol 32 ◽  
pp. 328-329
Author(s):  
Joseph E. Mazurkiewicz
Keyword(s):  
Electron Microscopy ◽  
Light Microscopy ◽  
Ultrastructural Level ◽  
Electron Microscopic ◽  
Biological Interest ◽  
Investigative Approach ◽  
Immunologic Activity ◽  
Dense Label

Immunocytochemistry is a powerful investigative approach in which one of the most exacting examples of specificity, that of the reaction of an antibody with its antigen, isused to localize tissue and cell specific molecules in situ. Following the introduction of fluorescent labeled antibodies in T950, a large number of molecules of biological interest had been studied with light microscopy, especially antigens involved in the pathogenesis of some diseases. However, with advances in electron microscopy, newer methods were needed which could reveal these reactions at the ultrastructural level. An electron dense label that could be coupled to an antibody without the loss of immunologic activity was desired.

Electron Microscopy of Mycoplasma Pneumoniae

1971 ◽  
Vol 29 ◽  
pp. 258-259 ◽  
Author(s):  
E. S. Boatman ◽  
G. E. Kenny
Keyword(s):  
Electron Microscopy ◽  
Light Microscopy ◽  
Growth Phase ◽  
Hela Cells ◽  
Sulfonic Acid ◽  
Gamma Globulin ◽  
Horse Serum ◽  
Morphological Aspects ◽  
The Family

Information concerning the morphology and replication of organism of the family Mycoplasmataceae remains, despite over 70 years of study, highly controversial. Due to their small size observations by light microscopy have not been rewarding. Furthermore, not only are these organisms extremely pleomorphic but their morphology also changes according to growth phase. This study deals with the morphological aspects of M. pneumoniae strain 3546 in relation to growth, interaction with HeLa cells and possible mechanisms of replication.The organisms were grown aerobically at 37°C in a soy peptone yeast dialysate medium supplemented with 12% gamma-globulin free horse serum. The medium was buffered at pH 7.3 with TES [N-tris (hyroxymethyl) methyl-2-aminoethane sulfonic acid] at 10mM concentration. The inoculum, an actively growing culture, was filtered through a 0.5 μm polycarbonate “nuclepore” filter to prevent transfer of all but the smallest aggregates. Growth was assessed at specific periods by colony counts and 800 ml samples of organisms were fixed in situ with 2.5% glutaraldehyde for 3 hrs. at 4°C. Washed cells for sectioning were post-fixed in 0.8% OSO4 in veronal-acetate buffer pH 6.1 for 1 hr. at 21°C. HeLa cells were infected with a filtered inoculum of M. pneumoniae and incubated for 9 days in Leighton tubes with coverslips. The cells were then removed and processed for electron microscopy.

Preservation of Plant Cell Surfaces For Scanning Electron Microscopy

1973 ◽  
Vol 31 ◽  
pp. 472-473
Author(s):  
Linda M. Sicko ◽  
Thomas E. Jensen
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Critical Point ◽  
Filter Paper ◽  
Freeze Drying ◽  
Cell Surfaces ◽  
Air Drying ◽  
Popular Method ◽  
Critical Point Drying ◽  
Scanning Electron

The use of critical point drying is rapidly becoming a popular method of preparing biological samples for scanning electron microscopy. The procedure is rapid, and produces consistent results with a variety of samples. The preservation of surface details is much greater than that of air drying, and the procedure is less complicated than that of freeze drying. This paper will present results comparing conventional air-drying of plant specimens to critical point drying, both of fixed and unfixed material. The preservation of delicate structures which are easily damaged in processing and the use of filter paper as a vehicle for drying will be discussed.

Development of 200 kV Scanning-Transmission Electron Microscope

1974 ◽  
Vol 32 ◽  
pp. 410-411
Author(s):  
H. Koike ◽  
S. Sakurai ◽  
K. Ueno ◽  
M. Watanabe
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Scanning Transmission Electron Microscope ◽  
The Other ◽  
Morphological Observation ◽  
Magnetic Domains ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Backscattered Electron ◽  
Increasing Demand

In recent years, there has been increasing demand for higher voltage SEMs, in the field of surface observation, especially that of magnetic domains, dislocations, and electron channeling patterns by backscattered electron microscopy. On the other hand, the resolution of the CTEM has now reached 1 ∼ 2Å, and several reports have recently been made on the observation of atom images, indicating that the ultimate goal of morphological observation has beem nearly achieved.

Sign in / Sign up

Export Citation Format

Share Document