Local analysis of strontium using fish scale by micro-PIXE with a CdTe X-ray detector

Sr is an indicator used in studies on fish migration. In this study, the Sr profiles of ridges, which are growth lines in fish scales, in Sakhalin taimen (Hucho perryi) were examined by micro-PIXE analysis. Sakhalin taimen were reared under freshwater conditions for six months. The ridges that formed during the rearing experiment were subjected to PIXE spot analysis. This analysis was performed in a 5 X 5 μm2 area in the center region of each ridge of the scale section, and the Sr levels were calculated using the thin-section standard. The mean Sr concentration in the ridges was 428± 48 μg/g. The quantitative PIXE spot analysis successfully provided Sr profiles for the scale corresponding to ridge formation.Read More: http://www.worldscientific.com/doi/abs/10.1142/S012908351240025

Mandibles of Japanese subterranean termites, Coptotermes formosanus Shiraki and Reticulitermes speratus (Kolbe)

Worker mandibles of two economically important subterranean pest termites, Coptotermes formosanus Shiraki and Reticulitermes speratus (Kolbe), were investigated for their chemical properties and arrangement with special reference to the pigmentation and the particle-removing capacity. Both species deposited Mn in cutting edges of mandibles, and the deposition seemed to be closely related to the pigmentation and the hardening of the mandibles.The maximum openings of mandibles and maxillaes of C.formosanus workers were 0.45mm and 0.88mm, respectively, and the minimum gap between mandibles and maxillaes was 0.07mm.This theoretically results in that C.formosanus workers can remove particles with less than 1.9mm diameters if the particle is spherical in shape, coinciding well with the laboratory test results that 1.7-2.4mm sized particles were effective to prevent the invasion of workers of C.formosanus. In addition, workers of C.formosanus showed the maximum head width of approximately 1.2mm, indicating the particles with less than 2.9mm diameters are small enough to prevent the invasion of workers of C.formosanus. This also has no contradiction with the laboratory test results. These results strongly suggest that basic researches on termite mandibles can be the breakthrough to develop not only new termite control measures but also new biomimetic composite materials