Multiresolutional image analysis of wood and other materials

The gloss of wood is a unique texture compared to that of other materials. To express it quantitatively, two digital-image analyses were performed. One method was multiresolutional contrast analysis, which was the new method developed in this study. The other method was fractal image analysis. Twenty-four specimens, including solid woods, wood-plastic composites (WPCs), printed grains, and granites, were prepared. Digital images of specimens were obtained in five sizes and in two illuminant directions (perpendicular and parallel to the grain). The multiresolutional contrast values of perpendicular illuminated images were calculated and compared among specimens. The result of this quantitative analysis was that the gloss of wood was characterized by bright spots in a relatively small area. Using fractal analysis, the fractal dimension of a digital image was used as an index of brightness changes, not for expressing the self-similarity. These indices showed results similar to those of the multiresolutional contrast analysis.Part of this paper was presented at the 47th annual meeting of the Japan Wood Research Society in Kochi, April 1997     

Effect of temperature and relative humidity on the tolerance of the Japanese clam, Ruditapes philippinarum (Adams & Reeve), to air exposure

Laboratory studies showed that higher relative humidity (RH) and lower air temperature increase the tolerance of the Japanese clam, Ruditapes philippinarum (Adams & Reeve), to exposure. Aerial respiration of the clam was also measured. At high RH, the exposure time which gave 50% survival (LT₅₀) was 1.97 and 1.75 times longer than in low RH at air temperatures of 15 and 25 °C, respectively. At 15 °C, all clams previously acclimatized at 15 °C survived for 58 h at low RH and 102 h at high RH. These differences can potentially be exploited to improve the shipment of clams. The aerial respiration experiment showed that the increase of the oxygen consumption rate at 25 °C was greater than that at 15 °C, following an increase in exposure time. The aerial respiration rates of the clams were ≈ 41.6% and 50.0% of those in water at 25 and 15 °C, respectively. The survival of the clams in air was dependent on aerobic rather than anaerobic respiration.     

The roles of structural imperfections in InGaN-based blue light-emitting diodes and laser diodes

REVIEW High-efficiency light-emitting diodes emitting amber, green, blue, and ultraviolet light have been obtained through the use of an InGaN active layer instead of a GaN active layer. The localized energy states caused by In composition fluctuation in the InGaN active layer are related to the high efficiency of the InGaN-based emitting devices. The blue and green InGaN quantum-well structure light-emitting diodes with luminous efficiencies of 5 and 30 lumens per watt, respectively, can be made despite the large number of threading dislocations (1 x 10(8) to 1 x 10(12) cm-2). Epitaxially laterally overgrown GaN on sapphire reduces the number of threading dislocations originating from the interface of the GaN epilayer with the sapphire substrate. InGaN multi-quantum-well structure laser diodes formed on the GaN layer above the SiO2 mask area can have a lifetime of more than 10,000 hours. Dislocations increase the threshold current density of the laser diodes.     

Signal Mediators for Phytoalexin Production in Defense Response of Oats Elicited by Victorin as a Specific Elicitor

Signals mediating phytoalexin (PA) production were analyzed in primary leaves of oats cv. Iowa X469 treated with an elicitor victorin. Production of the PA avenanthramide A was inhibited by DPI, an inhibitor of NADPH oxidase/nitric oxide synthase (NOS) and the NOS inhibitors l-NMMA and 1,3-PBIT. However, catalase and superoxide dismutase (SOD) hardly suppressed it. From the data, NO functions as a major reactive oxygen species in signal transduction leading to PA production in the defense response of oats. EGTA, verapamil and ruthenium red inhibited PA production, suggesting that Ca²⁺ influx into the cytoplasm and intracellular Ca²⁺ movement are involved in the defense response. Trifluoperazine, a calmodulin function inhibitor, and K-252a, a serine/threonine kinase inhibitor, also suppressed the accumulation, whereas okadaic acid, a serine/threonine phosphatase inhibitor, did not suppress it, suggesting the involvement of calmodulin and protein kinase, but not of phosphatase in PA production. Received 24 December 1999/ Accepted in revised form 4 February 2000     

Tbx5 and the retinotectum projection

Dorsal and ventral aspects of the eye are distinct from the early stages of development. The developing eye cup grows dorsally, and the choroidal fissure is formed on its ventral side. Retinal axons from the dorsal and ventral retina project to the ventral and dorsal tectum, respectively. Misexpression of the Tbx5 gene induced dorsalization of the ventral side of the eye and altered projections of retinal ganglion cell axons. Thus, Tbx5 is involved in eye morphogenesis and is a topographic determinant of the visual projections between retina and tectum.     

Ecological studies of Yersinia enterocolitica I. Dissemination of Y. enterocolitica in pigs

Pigs were examined on five farms for carrier status of Yersinia enterocolitica. Yersinia enterocolitica biovar 4, serovar 3, phagovar VIII was isolated consistently from the feces of fattening pigs on one farm and sporadically from those of similar pigs on the other farms and of sows on all five farms, during a one-year period of weekly surveys. Seasonal variation was not a feature of fattening pigs on a highly contaminated farm. In other pigs, however, the organisms were not isolated during the summer months. On a highly contaminated farm, the organisms were excreted in the feces of 8 to 15-week-old pigs within 1–3 weeks of entering pens which were thought to be contaminated with the organisms. On a detailed observation of natural infection of Y. enterocolitica in eight pigs, the organism appeared in the pigs' feces within 2–7 weeks of them being moved to a pen which had been washed thoroughly after becoming contaminated, by a previous group of pigs, with feces containing 10⁵ viable organisms per g. Thus, Y. enterocolitica is apparently transmitted from infected feces or picked up from the floor of a contaminated pen, and the regular schedule of pig movement among the pens is an important factor in the spread of Y. enterocolitica within a piggery. Intestinal colonization continues for a long time and does not occur by re-infection. The organisms were not isolated from eight pigs at the time of slaughter, and their serum O-agglutinin titers were $\text{1}\text{40}$ or less. Thus, circulating antibody may not inhibit intestinal colonization by Y. enterocolitica.     

Detection of chicken anaemia virus DNA from formalin-fixed tissues by polymerase chain reaction

Chicken anaemia virus was detectable from various samples such as cell-free virus, infected cells, unfixed liver homogenates, formalin-fixed liver homogenate or formalin-fixed paraffin-embedded ( ) tissues from experimental or field infected chicks using assay. The detection limit of the first PCR assay was 1 infected cell or 10^−1·5, ₅₀ of cell-free virus (strain A2). The nested assay increased the sensitivity 10- or 100-fold. was detectable in the other 14 Japanese strains isolated from 1976 to 1994 by the assay. All the amplified products were digested with BglII, HindIII, PstI and SacI. These results suggest that the region amplified was highly conserved among the strains. The nested assay was very sensitive. However, was detectable in most field samples using the first assay. Therefore, the nested assay may not always be necessary. In contrast, the nested PCR assay was necessary to detect in tissues or formalin-fixed material. Use of the assay in detection from tissues may be most valuable in diagnosis of diseases caused by or associated with , because it allows detection of both microscopic lesions and .