Effects of Pesticides, Temperature, Light, and Chemical Constituents of Soil on Nitrogen Fixation

The mammary gland ultrastructure in various functional states is the object of our investigations. The material prepared for electron microscopic examination by the conventional chemical methods has several limitations, the most important are the protein denaturation processes and the loss of large amounts of chemical constituents from the cells. In relevance to this,one can't be sure about a degree the observed images are adequate to the realy ultrastructure of a living cell. To avoid the disadvantages of the chemical preparation methods,some autors worked out alternative physical methods based on tissue freezing / freeze-drying, freeze-substitution, freeze-eatching techniqs/; actually the technique of cryoultraraicrotomy,i,e.cutting ultrathin sections from deep frozen specimens is assented as a complete alternative method. According to the limitations of the routine plastic embbeding methods we were interested to analize the mammary gland ultrastructure during lactation by the cryoultramicrotomy method.

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Sem and X-Ray Analysis of Renal and Biliary Calculi

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100091512 ◽

1976 ◽

Vol 34 ◽

pp. 306-307

Author(s):

R. J. Narconis ◽

G. L. Johnson

Keyword(s):

Chemical Constituents ◽

Natural State ◽

X Ray Diffraction ◽

Chemical Methods ◽

X Ray ◽

Additional Dimension ◽

Biliary Calculi ◽

Calculus Formation ◽

Scanning Electron

Analysis of the constituents of renal and biliary calculi may be of help in the management of patients with calculous disease. Several methods of analysis are available for identifying these constituents. Most common are chemical methods, optical crystallography, x-ray diffraction, and infrared spectroscopy. The application of a SEM with x-ray analysis capabilities should be considered as an additional alternative.A scanning electron microscope equipped with an x-ray “mapping” attachment offers an additional dimension in its ability to locate elemental constituents geographically, and thus, provide a clue in determination of possible metabolic etiology in calculus formation. The ability of this method to give an undisturbed view of adjacent layers of elements in their natural state is of advantage in determining the sequence of formation of subsequent layers of chemical constituents.

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