SUMMARY: A lectin‐binding assay was applied to the rainbow trout, Oncorhynchus mykiss, sacculus in order to identify specific sugars in the otolith organ. The binding of biotinylated lectins to the sagitta, otolith membrane and saccular epithelial cells was detected by histochemistry, and their binding to the EDTA‐soluble fraction of the otolith matrix and saccular endolymph was detected by dot‐blot analysis. N‐Acetylglucosamine (GlcNAc) and mannose (Man) were identified in the otolith matrix with both techniques. These data indicate that glycoproteins in the otolith matrix have N‐glycosidically linked sugar chains. In the otolith membrane, GlcNAc and Man were identified in the subcupular meshwork, whereas only Man was identified in the gelatinous layer. This is in line with the hypothesis that a part of the subcupular meshwork is incorporated into the otolith as an organic matrix. The saccular epithelial cells reacted with at least one of the lectins which bound to the otolith matrix. The endolymph had the same reactivity with lectins as the otolith matrix. Thus, we suggest that otolith‐matrix carbohydrates are produced in the saccular epithelial cells, secreted into the endolymph, and deposited onto the otolith.

Eight thin iron wires were embedded in a cement test block to evaluate corrosion behavior during cement carbonization by CO 2 absorption. The gases supplied sequentially to the chamber containing the cement test block were air, CO 2 , and then air. Electrical resistance measurement of the thin wires revealed that the iron wires remained passivated during the supply of air and uncorroded during the supply of CO 2 to promote carbonization. The iron wires started corroding from the surface when the air was resupplied after carbonization due to the presence of O 2 in the air as an oxidizing agent. A set of two-electrode impedances between two selected iron wires was measured as a function of depth from the surface. The impedance of all electrodes dropped considerably several hours after the CO 2 supply due to the difference in the immersion potential of the iron wires as a function of depth, that is, the pH transition from alkaline to neutral. Consequently, the iron wires were polarized when electrically connected to each other during carbonization. After carbonization, each iron wire showed an impedance response corresponding to its corrosion condition, which depended on its depth.

Eight thin iron wires were embedded in a cement test block to evaluate the corrosion behavior during the carbonization of cement by the CO 2 gas absorption. The gas supplied to the chamber containing the cement test block was subsequently changed as air, CO 2 , and air. Electric resistance measurement of thin wires revealed that the iron kept passivated during supplying of air and uncorroded during the CO 2 supply to promote carbonization and began to be corroded from the surface side when the air was resupplied after carbonization due to the existence of oxygen in the air as an oxidizing agent. A series of two-electrode impedance between the selected two iron wires were measured as a function of depth from the surface. The impedance of all electrodes dropped considerably several hours after the CO 2 supply. That was caused by the difference in the immersion potential of iron wires as a function of depth, i.e., pH transition from alkaline to neutral range. As a result, iron wires were polarized when electrically connected to each other during the progress of carbonization. When the carbonization was completed, each iron wire showed the impedance response corresponding to the corrosion condition depending on the depth.