Isolation and Partial Chemical Analysis of Exopolysaccharides from the Marine Fouling Diatom Navicula subinflata

Cells of a freshwater sediment bacterium produced firmly bound extracellular polymers in laboratory cultures which, at the ultrastructural level, resembled those produced by natural sediment bacterial populations. Production of the exopolymers during subculture was maintained by using as a source of inoculum the population of cells which adhered to each other and to the wall of the glass culture vessel. The exopolymers were selectively released from the cells by blending and centrifugation in the presence of EDTA. Evaluation of glucose-6-phosphate dehydrogenase activity and 2-keto-3-deoxyoctonate concentration indicated that only small amounts of intracellular and cell wall components were released from the cells during exopolymer removal. Chemical analysis of the isolated crude exopolymer material indicated that it contained protein, polysaccharide, and DNA. The treatment promoted the selective isolation of firmly bound polymers from the surface of adherent cells.

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Some Observations on the Formation of Wollastonite from Calcite and Quartz

Canadian Journal of Earth Sciences ◽

10.1139/e71-078 ◽

1971 ◽

Vol 8 (7) ◽

pp. 844-851 ◽

Cited By ~ 7

Author(s):

T. M. Gordon

Keyword(s):

Electron Microscope ◽

Reaction Mechanism ◽

Chemical Analysis ◽

Scanning Electron Microscope ◽

Thin Layer ◽

Total Pressure ◽

Initial Period ◽

Experimental Scatter ◽

Partial Chemical ◽

Scanning Electron

Mixtures of powdered calcite and quartz were reacted for various lengths of time at a total pressure of 2000 bars, 650 °C, in an H2O–CO2 fluid. Extent of formation of wollastonite was determined by partial chemical analysis of run products. Experimental scatter precludes detailed analysis of the reaction mechanism.The data show that approximately 40% reaction takes place in the first 24 h, and that after this initial period the rate decreases. Examination of run products shows the calcite to be surrounded by radiating wollastonite crystals. This suggests that the wollastonite cover forms during the initial stages of reaction and, by shielding the calcite, suppresses the reaction.Single cleavage flakes of calcite were packed in −325 mesh quartz and allowed to react under the same conditions as the powders. A scanning electron microscope was used to examine and photograph the fragment surfaces at the conclusion of the experiments.Examination of the photographs shows the calcite to be completely covered with a thin layer of wollastonite crystals. Details of the morphology suggest that the wollastonite grew outward from nucleation centers and that the solution of calcite and quartz may have been accelerated near growing wollastonite. Although no details of the reaction mechanism can be deduced, the model favored here is that growth was most rapid near the calcite–wollastonite interface and the mantling effect slowed the reaction by preventing the transport of silica to the calcite surface.

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Purification and partial chemical analysis of Sindbis virus

Virology ◽

10.1016/0042-6822(63)90092-8 ◽

1963 ◽

Vol 20 (3) ◽

pp. 433-445 ◽

Cited By ~ 79

Author(s):

E.R. Pfefferkorn ◽

Hilda Salmon Hunter

Keyword(s):

Chemical Analysis ◽

Sindbis Virus ◽

Partial Chemical

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ON THE ROTIFERA AND LIMNOLOGY OF AN HUNGARIAN BOG POND

Canadian Journal of Zoology ◽

10.1139/z62-063 ◽

1962 ◽

Vol 40 (5) ◽

pp. 677-684 ◽

Cited By ~ 1

Author(s):

Thomas F. Nogrady

Keyword(s):

New Species ◽

Chemical Analysis ◽

Two New Species ◽

Partial Chemical

The results of a brief survey of the limnology of an Hungarian bog pond and a partial chemical analysis of the water are given. The Rotifera, Gastrotricha, Cladocera, and Copepoda, found between June and October, are given, and some of the Rotifera and two new species (Cephalodella conica and Lecane urna) are described.

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Aspects of microanalysis in a transmission electron microscope

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100109690 ◽

1978 ◽

Vol 36 (1) ◽

pp. 510-511

Author(s):

R. Sinclair ◽

B.E. Jacobson

Keyword(s):

Grain Size ◽

Electron Beam ◽

Electron Microscope ◽

Chemical Analysis ◽

Transmission Electron Microscope ◽

Vapor Deposition ◽

Critical Currents ◽

X Ray ◽

Fine Grain ◽

Transmission Electron

INTRODUCTIONThe prospect of performing chemical analysis of thin specimens at any desired level of resolution is particularly appealing to the materials scientist. Commercial TEM-based systems are now available which virtually provide this capability. The purpose of this contribution is to illustrate its application to problems which would have been intractable until recently, pointing out some current limitations.X-RAY ANALYSISIn an attempt to fabricate superconducting materials with high critical currents and temperature, thin Nb3Sn films have been prepared by electron beam vapor deposition [1]. Fine-grain size material is desirable which may be achieved by codeposition with small amounts of Al2O3 . Figure 1 shows the STEM microstructure, with large (∽ 200 Å dia) voids present at the grain boundaries. Higher quality TEM micrographs (e.g. fig. 2) reveal the presence of small voids within the grains which are absent in pure Nb3Sn prepared under identical conditions. The X-ray spectrum from large (∽ lμ dia) or small (∽100 Ǻ dia) areas within the grains indicates only small amounts of A1 (fig.3).

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Integrated morphometrical and electron energy loss image analysis in cytochemistry

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100153981 ◽

1989 ◽

Vol 47 ◽

pp. 402-403

Author(s):

W.C. de Bruijn ◽

A.A.W. de Jong ◽

C.W.J. Sorber

Keyword(s):

Image Analysis ◽

Acid Phosphatase ◽

Chemical Analysis ◽

Active Form ◽

List Type ◽

Type Number ◽

Enzyme Cytochemistry ◽

Related Data ◽

Endogenous Peroxidase ◽

Electron Energy Loss

One aspect of enzyme cytochemistry is, whether all macrophage lysosomal hydrolytical enzymes are present in an active form, or are activated upon stimulation. Integrated morphometrical and chemical analysis has been chosen as a tool to illucidate that cytochemical problem. Mouse peritoneal resident macrophages have been used as a model for this complicated integration of morphometrical and element-related data. Only aldehyde-fixed cells were treated with three cytochemical reactions to detect different enzyme activities within one cell (for details see [1,2]). The enzyme-related precipitates anticipated to be differentiated, were:(1).lysosomal barium and sulphur from aryl sulphatase activity,(2).lysosomal cerium and phosphate from acid phosphatase activity and(3).platinum/di-amino-benzidine( D A B) complex from endogenous peroxidase activity.

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Microdomains in BaFeO3-y (0.35 < y < 0.50)

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100177039 ◽

1990 ◽

Vol 48 (4) ◽

pp. 780-781

Author(s):

M. Vallet-Regí ◽

M. Parras ◽

J.M. González-Calbet ◽

J.C. Grenier

Keyword(s):

Electron Diffraction ◽

Chemical Analysis ◽

Monoclinic Phase ◽

Orthorhombic Phase ◽

Total Iron ◽

Zone Axis ◽

Electron Micrograph ◽

X Ray Diffraction ◽

X Ray ◽

Compositional Variations

BaFeO3-y compositions (0.35<y<0.50) have been investigated by means of electron diffraction and microscopy to resolve contradictory results from powder X-ray diffraction data.The samples were obtained by annealing BaFeO2.56 for 48 h. in the temperature range from 980°C to 1050°C . Total iron and barium in the samples were determined using chemical analysis and gravimetric methods, respectively.In the BaFeO3-y system, according to the electron diffraction and microscopy results, the nonstoichiometry is accommodated in different ways as a function of the composition (y):In the domain between BaFeO2.5+δBaFeO2.54, compositional variations are accommodated through the formation of microdomains. Fig. la shows the ED pattern of the BaFeO2.52 material along thezone axis. The corresponding electron micrograph is seen in Fig. 1b. Several domains corresponding to the monoclinic BaFeO2.50 phase, intergrow with domains of the orthorhombic phase. According to that, the ED pattern of Fig. 1a, can be interpreted as formed by the superposition of three types of diffraction maxima : Very strong spots corresponding to a cubic perovskite, a set of maxima due to the superposition of three domains of the monoclinic phase along [100]m and a series of maxima corresponding to three domains corresponding to the orthorhombic phase along the [100]o.

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