The Bremen Cog of 1380 – An electron microscopic study of its degraded wood before and after stabilization with PEG

Holzforschung ◽  
2004 ◽  
Vol 58 (3) ◽  
pp. 211-218 ◽  
Author(s):  
P. Hoffmann ◽  
A. Singh ◽  
Y.S. Kim ◽  
S.G. Wi ◽  
I.-J. Kim ◽  
...  
Keyword(s):  
Microscopic Study ◽  
Electron Microscopic Study ◽  
Cell Walls ◽  
Cell Types ◽  
Electron Microscopic ◽  
Before And After ◽  
Peg Treatment ◽  
Extensive Degradation ◽  
Archaeological Objects ◽  
Impregnated Wood

Abstract The Bremen Cog is a big ship built AD 1380 from oak wood. After its recovery from the river Weser, the water-logged ship's timbers were successfully stabilized using a novel two-step polyethylene glycol (PEG) treatment. An electron microscopic study of the patterns of degradation and of the distribution of PEG within the Cog wood is described. Descriptions like these do not exist for many well known archaeological objects. SEM revealed that in areas with extensive degradation, wood cell walls are thinned and cells have a distorted appearance. TEM provided evidence that the wood has been degraded primarily by erosion bacteria. The stabilization treatment involved impregnation first with PEG 200 and then with PEG 3000. The SEM observations of PEG-impregnated wood revealed that in degraded tissues all cell types are well filled with PEG 3000. Non-degraded tissues are impermeable to PEG 3000 and are impregnated only with PEG 200. SEM confirmed earlier fluorescence microscopic evidence, that PEG 200 is absorbed by the cell walls.

Selective staining of secretory granules of adrenal medullary cells by silver methenamine: A light and electron microscopic study

1968 ◽  
Vol 46 (5) ◽  
pp. 745-747 ◽  
Author(s):  
William W. L. Chang ◽  
Sergio A. Bencosme
Keyword(s):  
Microscopic Study ◽  
Adrenal Medulla ◽  
Electron Microscopic Study ◽  
Secretory Granules ◽  
Cell Types ◽  
Cell Type ◽  
Glutaraldehyde Fixation ◽  
Electron Microscopic ◽  
Selective Staining ◽  
The Third

A reevaluation of the silver methenamine reaction as an electron stain has ensued from recent use of glutaraldehyde fixation alone. By this technique, three cell types of rat adrenal medulla were found: (i) the norepinephrine-containing cells showed selectively stained, irregular, black granules; (ii) the epinephrine-containing cells showed round, light-grey granules; and (iii) the third cell type showed round granules like those of epinephrine-containing cells, but black in color, similar to those of the norepinephrine-containing cells.

An electron microscopic study of the formation and structure of the periostracum in Astarte (Bivalvia)

1974 ◽  
Vol 52 (12) ◽  
pp. 1463-1471 ◽  
Author(s):  
A. S. M. Saleuddin
Keyword(s):  
Microscopic Study ◽  
Electron Microscopic Study ◽  
Cell Types ◽  
Homogeneous Layer ◽  
Fibrous Layer ◽  
Electron Microscopic ◽  
The Third ◽  
Thin Sectioning ◽  
Structural Details ◽  
Different Cell Types

An electron microscopic study of the outer and middle folds of the mantle edge of Astarte castanea reveals the fine-structural details of the cells which are involved in the formation of the periostracum. There are four types of cells in the outer fold whereas there is only one type in the middle fold. The role of different cell types in the formation of the periostracum has been discussed. The periostracum originates in the intercellular space between the basal cell of the outer fold and the first cell of the middle fold. Even at the point of origin it consists of two outer membranous layers and the inner dark homogeneous layer. The fibrous translucent layer, which is the third layer of the fully mature periostracum, does not appear until the young periostracum has moved down the periostracal groove at the level of the third cell. As the periostracum matures, the two membranous layers remain remarkably constant in width, whereas the two inner layers, dark homogeneous and fibrous translucent, increase in thickness. Scanning electron microscopy and thin sectioning reveal that the fully mature periostraca of A. castanea and A. elliptica appear uniformly pitted, but the nature of the pits between the two species is different. The fibrils of the fibrous layer show either uniform or random arrangements, depending on the region. It is the innermost part of the fibrous layer of the periostracum that provides the nuclei for calcification.

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