National Institute of Advanced Industrial Science and Technology

About: National Institute of Advanced Industrial Science and Technology is a government organization based out in Tsukuba, Ibaraki, Japan. It is known for research contribution in the topics: Catalysis & Thin film. The organization has 22114 authors who have published 65856 publications receiving 1669827 citations. The organization is also known as: Sangyō Gijutsu Sōgō Kenkyū-sho.

Chondrulelike Objects in Short-Period Comet 81P/Wild 2

Abstract: The Stardust spacecraft returned cometary samples that contain crystalline material, but the origin of the material is not yet well understood. We found four crystalline particles from comet 81P/Wild 2 that were apparently formed by flash-melting at a high temperature and are texturally, mineralogically, and compositionally similar to chondrules. Chondrules are submillimeter particles that dominate chondrites and are believed to have formed in the inner solar nebula. The comet particles show oxygen isotope compositions similar to chondrules in carbonaceous chondrites that compose the middle-to-outer asteroid belt. The presence of the chondrulelike objects in the comet suggests that chondrules have been transported out to the cold outer solar nebula and spread widely over the early solar system.

Rickettsia Symbiont in the Pea Aphid Acyrthosiphon pisum: Novel Cellular Tropism, Effect on Host Fitness, and Interaction with the Essential Symbiont Buchnera

Abstract: In natural populations of the pea aphid Acyrthosiphon pisum, a facultative bacterial symbiont of the genus Rickettsia has been detected at considerable infection frequencies worldwide. We investigated the effects of the Rickettsia symbiont on the host aphid and also on the coexisting essential symbiont Buchnera. In situ hybridization revealed that the Rickettsia symbiont was specifically localized in two types of host cells specialized for endosymbiosis: secondary mycetocytes and sheath cells. Electron microscopy identified bacterial rods, about 2 μm long and 0.5 μm thick, in sheath cells of Rickettsia-infected aphids. Virus-like particles were sometimes observed in association with the bacterial cells. By an antibiotic treatment, we generated Rickettsia-infected and Rickettsia-eliminated aphid strains with an identical genetic background. Comparison of these strains revealed that Rickettsia infection negatively affected some components of the host fitness. Quantitative PCR analysis of the bacterial population dynamics identified a remarkable interaction between the coexisting symbionts: Buchnera population was significantly suppressed in the presence of Rickettsia, particularly at the young adult stage, when the aphid most actively reproduces. On the basis of these results, we discussed the possible mechanisms that enable the prevalence of Rickettsia infection in natural host populations in spite of the negative fitness effects observed in the laboratory.

Oxidation resistance of Cr1-XAlXN and Ti1-XAlXN films

Abstract: Cr1−XAlXN films were synthesized on mirror-polished stainless steel substrates by the arc ion plating method using Cr1−XAlX alloy targets with diffent Al contents. Oxidation resistance of films was estimated by heating substrates in air at 800, 900 and 1000 °C and subsequent analysis by the X-ray diffraction method (XRD). The XRD peaks from Ti0.7Al0.3N films, annealed at 800 °C for 14 h, disappeared and the peaks from iron oxides consequently appeared. The oxidation resistance of Ti1−XAlXN films improved with increasing Al content X. On the other hand, the peaks from Cr1−XAlXN films which were annealed at 800 °C did not change at all, but Cr1−XAlXN films were slightly oxidized over 900 °C. It is considered that the oxidation resistance of Cr1−XAlXN films was superior to that of Ti1−XAlXN films.