Intervascular Pit Plugs in the Transition Zone Between Sapwood and Wetwood of Ulmus Americana L.

IAWA Journal ◽  
1983 ◽  
Vol 4 (1) ◽  
pp. 27-31 ◽  
Author(s):  
Tambra Thompson ◽  
Richard Jagels
Keyword(s):  
Transition Zone ◽  
Ulmus Americana ◽  
Bordered Pit ◽  
X Ray ◽  
American Elm ◽  
Vascular Elements ◽  
Freeze Dried ◽  
Hypo Thesis ◽  
Scanning Electron

Scanning electron microscoPlc analysis of freeze-dried American elm wood revealed the presence of unique plugs in bordered pit chambers of vascular elements. Non-dispersive X-ray analysis of these plugs demonstrated the presence of high levels of calcium and potassium. Some pits contained only fragmentary deposits or bacteria. An hypo thesis is proposed to account for the precipitation of CaCO3 in the bordered pit chambers of vascular elements at the sapwood-wetwood boundary, resulting in the formation of amorphous plugs that fil! the pit chamber.

Localization of Silver in the Spleen of Argyric Rats by Energy Dispersive X-Ray Analysis Coupled with Scanning and Transmission Electron Microscopy

1977 ◽  
Vol 35 ◽  
pp. 504-506
Author(s):  
G. Pereira
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Computer Assisted ◽  
White Pulp ◽  
Reticular Cell ◽  
X Ray ◽  
Transmission Electron ◽  
Freeze Dried ◽  
Scanning Electron

Previous electron microscopic observations of the spleen have revealed the white pulp to be completely separated from the extravasated blood in the surrounding marginal zone by a strategically-located, double layer of reticular cells ensheathing a coarse reticular fiber. Similarly, a single reticular cell layer has been observed to form a continuous investment for all white pulp capillaries. To test the significance of this apparent isolation of the splenic white pulp from the blood, the distribution and composition of silver deposits in the spleen of argyric rats were determined by transmission and scanning electron microscopy coupled with computer-assisted x-ray analysis.Young male albino rats were made argyric by supplying them for many months with drinking water to which 1.5gm per liter of silver nitrate had been added. Specimens from the spleens of control and argyric animals were prepared for conventional transmission electron microscopy by glutaraldehyde-osmium fixation. For scanning electron microscopy, other specimens were fixed in buffered glutaraldehyde, freeze-dried in vacuo, coated with a thin film of gold- palladium and examined in a Cambridge Stereoscan Mark II.

Diffusible ions in amebae studied by scanning electron microscopy and X-ray microanalysis

1978 ◽  
Vol 36 (2) ◽  
pp. 112-113
Author(s):  
D. Schäfer ◽  
K. Zierold
Keyword(s):  
Calcium Ions ◽  
Aluminum Foil ◽  
Amoeba Proteus ◽  
Rapid Freezing ◽  
Cultivation Medium ◽  
X Ray ◽  
Freeze Dried ◽  
Energy Dispersive Microanalysis ◽  
Scanning Electron ◽  
Investigation Procedure

Calcium ions are involved in the regulation of ameboid movement but, so far, little is known about the distribution of calcium and other electrolyte ions in the amebae. This problem seems solvable by X-ray microanalysis with the scanning electron microscope (SEM). For this purpose Amoeba proteus was placed in the cultivation medium (Chalkey's solution) on the specimen stub covered with aluminum foil. Rapid freezing was done in liquid Freon 12 or propane precooled by liquid nitrogen. The specimens were either freeze-dried at -45° C for 15 hours and then coated with carbon or kept in the deep-frozen state throughout the preparation and investigation procedure by using a special cooling chain method. After coating ice was sublimated in the SEM under visual control until the ameboid structures became visible. Energy-dispersive microanalysis was done at 12.5 keV and 0.1 - 0.5 nA.

scholarly journals Element concentration changes in mitotically active and postmitotic enterocytes. An x-ray microanalysis study.

1979 ◽  
Vol 80 (2) ◽  
pp. 444-450 ◽  
Author(s):  
I L Cameron ◽  
N K Smith ◽  
T B Pool
Keyword(s):  
Element Concentration ◽  
X Ray ◽  
Tissue Sections ◽  
Elemental Concentrations ◽  
Late Anaphase ◽  
Freeze Dried ◽  
Concentration Changes ◽  
Analytical Equipment ◽  
Scanning Electron ◽  
Mitotic Chromatin

Unfixed freeze-dried and uncoated tissue sections of the mouse duodenum were suspended across a hole in a carbon planchet and analyzed in a scanning electron microscope fitted with energy-dispersive x-ray analytical equipment. Computer analysis of the x-ray spectra allowed elemental microanalysis of the nucleus, cytoplasm, and late anaphase-early telophase chromatin regions in the cryptal and villus enterocytes. Elemental concentrations (mmol/kg dry wt) were measured for Na, Mg, P, S, Cl, K, and Ca. None of the elements were compartmentalized preferentially in either the nucleus or the cytoplasm of interphase enterocytes of crypts or in postmitotic enterocytes of villi. In contrast, Ca, S, and Cl are detectable in significantly higher concentrations in mitotic chromatin of dividing enterocytes of the crypt as compared to surrounding mitotic cytoplasm, but Na, Mg, and P are in lower concentrations in the mitotic chromatin as compared to mitotic cytoplasm. Interphase enterocytes of crypts have higher concentrations of Mg, P, and K, and lower concentrations of Na than do postmitotic enterocytes of villi.

scholarly journals Scanning electron probe x-ray microanalysis of elemental distributions in freeze-dried cryosections of Bacillus coagulans spores.

1981 ◽  
Vol 147 (2) ◽  
pp. 670-674 ◽  
Author(s):  
M Stewart ◽  
A P Somlyo ◽  
A V Somlyo ◽  
H Shuman ◽  
J A Lindsay ◽  
...  
Keyword(s):  
Electron Probe ◽  
Bacillus Coagulans ◽  
X Ray ◽  
Freeze Dried ◽  
Scanning Electron

scholarly journals Nickel hyperaccumulation in New Caledonian Hybanthus (Violaceae) and occurrence of nickel-rich phloem in Hybanthus austrocaledonicus

2020 ◽  
Vol 126 (5) ◽  
pp. 905-914 ◽  
Author(s):  
Adrian L D Paul ◽  
Vidiro Gei ◽  
Sandrine Isnard ◽  
Bruno Fogliani ◽  
Guillaume Echevarria ◽  
...  
Keyword(s):  
Leaf Blade ◽  
New Caledonia ◽  
Phloem Tissue ◽  
X Ray ◽  
Nickel Hyperaccumulation ◽  
Freeze Dried ◽  
Field Samples ◽  
Hyperaccumulator Plants ◽  
Ni Accumulation ◽  
Scanning Electron

Abstract Background and Aims Hybanthus austrocaledonicus (Violaceae) is a nickel (Ni) hyperaccumulator endemic to New Caledonia. One of the specimens stored at the local herbarium had a strip of bark with a remarkably green phloem tissue attached to the sheet containing over 4 wt% Ni. This study aimed to collect field samples from the original H. austrocaledonicus locality to confirm the nature of the green ‘nickel-rich phloem’ in this taxon and to systematically assess the occurrence of Ni hyperaccumulation in H. austrocaledonicus and Hybanthus caledonicus populations. Methods X-ray fluorescence spectroscopy scanning of all collections of the genus Hybanthus (236 specimens) was undertaken at the Herbarium of New Caledonia to reveal incidences of Ni accumulation in populations of H. austrocaledonicus and H. caledonicus. In parallel, micro-analytical investigations were performed via synchrotron X-ray fluorescence microscopy (XFM) and scanning electron microscopy with X-ray microanalysis (SEM-EDS). Key Results The extensive scanning demonstrated that Ni hyperaccumulation is not a characteristic common to all populations in the endemic Hybanthus species. Synchrotron XFM revealed that Ni was exclusively concentrated in the epidermal cells of the leaf blade and petiole, conforming with the majority of (tropical) Ni hyperaccumulator plants studied to date. SEM-EDS of freeze-dried and frozen-hydrated samples revealed the presence of dense solid deposits in the phloem bundles that contained >8 wt% nickel. Conclusions The occurrence of extremely Ni-rich green phloem tissues appears to be a characteristic feature of tropical Ni hyperaccumulator plants.

X-ray microanalysis of frozen-hydrated, freeze-dried, and critical point dried leaf specimens: determination of soluble and insoluble chemical elements at Erysiphe graminis epidermal cell papilla sites in barley isolines containing Ml-o and ml-o alleles

1993 ◽  
Vol 71 (2) ◽  
pp. 284-296 ◽  
Author(s):  
R. J. Zeyen ◽  
G. G. Ahlstrand ◽  
T. L. W. Carver
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Critical Point ◽  
Epidermal Cell ◽  
Erysiphe Graminis ◽  
Specimen Preparation ◽  
X Ray ◽  
Freeze Dried ◽  
Leaf Epidermal Cell ◽  
Scanning Electron

Three specimen preparation procedures were used in conjunction with scanning electron microscopy and energy dispersive X-ray microanalysis to determine, by comparison among preparation methods, both soluble and insoluble elements at Erysiphe graminis – barley leaf epidermal cell encounter site areas where attempted fungal penetration by appressoria failed. Near isogenic lines (RISO 5678-R and RISO 5678-S) of barley differing by mutation at the Ml-o locus were used. The recessive ml-o allele conditions barley epidermal cells to respond with papilla-associated resistance to E. graminis, while the dominant Ml-o allele allows for successful penetration of the majority of E. graminis germlings. Frozen-hydrated and freeze-dried specimens maintained soluble and insoluble elements, while specimens fixed by formalin – acetic acid – alcohol and critical point dried lost soluble elements. The effects of specimen preparation on electron-beam penetration and depth of X-ray excitation were calculated and are illustrated. Mean elemental intensity values were corrected for X-ray absorption by nickel coating of specimens (used for electrical conductivity) and for X-ray detector efficiency. The elements Cl, K, Mn, Ca, and Mg were highly soluble both at recently deposited (16 h) and at matured (24 h) papilla deposition sites. Elemental Si levels were elevated and in a partially soluble state in recently deposited papilla sites (16 h), but Si became bound or insoluble in matured (24 h) papilla sites. Elemental P and S are insoluble. The physiological role of each element is briefly discussed relative to its known function in healthy and diseased plants, with emphasis on E. graminis – barley epidermal cell encounter site penetration failure. Key words: Erysiphe graminis, Hordeum vulgare, X-ray microanalysis, scanning electron microscopy.

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

Sem Studies of Co-Cr-Mo Surgical Implant Alloy Corrosion Behavior

1982 ◽  
Vol 40 ◽  
pp. 520-521
Author(s):  
Ann Chidester Van Orden ◽  
John L. Chidester ◽  
Anna C. Fraker ◽  
Pei Sung
Keyword(s):  
Electron Microscopy ◽  
Corrosion Behavior ◽  
Anodic Polarization ◽  
Saline Solution ◽  
Saturated Calomel Electrode ◽  
Physiological Saline ◽  
X Ray ◽  
Physiological Saline Solution ◽  
Scanning Electron

The influence of small variations in the composition on the corrosion behavior of Co-Cr-Mo alloys has been studied using scanning electron microscopy (SEM), energy dispersive x-ray analysis (EDX), and electrochemical measurements. SEM and EDX data were correlated with data from in vitro corrosion measurements involving repassivation and also potentiostatic anodic polarization measurements. Specimens studied included the four alloys shown in Table 1. Corrosion tests were conducted in Hanks' physiological saline solution which has a pH of 7.4 and was held at a temperature of 37°C. Specimens were mechanically polished to a surface finish with 0.05 µm A1203, then exposed to the solution and anodically polarized at a rate of 0.006 v/min. All voltages were measured vs. the saturated calomel electrode (s.c.e.).. Specimens had breakdown potentials near 0.47V vs. s.c.e.

Scanning and Transmission Microscopy of Nematocyst Batteries in Epitheliomuscular Cells of Hydra

1971 ◽  
Vol 29 ◽  
pp. 410-411 ◽  
Author(s):  
Jane A. Westfall ◽  
S. Yamataka ◽  
Paul D. Enos
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Osmium Tetroxide ◽  
External Surface ◽  
Three Dimensional ◽  
Surface Structures ◽  
Transmission Microscopy ◽  
Transmission Electron ◽  
Freeze Dried ◽  
Scanning Electron

Scanning electron microscopy (SEM) provides three dimensional details of external surface structures and supplements ultrastructural information provided by transmission electron microscopy (TEM). Animals composed of watery jellylike tissues such as hydras and other coelenterates have not been considered suitable for SEM studies because of the difficulty in preserving such organisms in a normal state. This study demonstrates 1) the successful use of SEM on such tissue, and 2) the unique arrangement of batteries of nematocysts within large epitheliomuscular cells on tentacles of Hydra littoralis.Whole specimens of Hydra were prepared for SEM (Figs. 1 and 2) by the fix, freeze-dry, coat technique of Small and Màrszalek. The specimens were fixed in osmium tetroxide and mercuric chloride, freeze-dried in vacuo on a prechilled 1 Kg brass block, and coated with gold-palladium. Tissues for TEM (Figs. 3 and 4) were fixed in glutaraldehyde followed by osmium tetroxide. Scanning micrographs were taken on a Cambridge Stereoscan Mark II A microscope at 10 KV and transmission micrographs were taken on an RCA EMU 3G microscope (Fig. 3) or on a Hitachi HU 11B microscope (Fig. 4).

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