Microstructures and Nitrides of Fe-Cr-N Ternary System

The microstructures and the characters of nitrides in various alloys of the Fe-Cr-N system in the range of 0.5 to 40% chromium with up to about 1% nitrogen were studied by optical- and electron-microscope and by X-ray diffraction and chemical analysis of the extracted residue. The results are summarized as follows : (1) The nitrides detected were Fe_4N, CrN and Cr_2N. (2) In the content of about 0.1% N, the changes in microstructure with the lowering of temperature were as follows : 0.5% Cr : γ→α+γ→α+γ+CrN→α+CrN+Fe_4N ; about 0.5～6% Cr : γ→α+γ→α+γ+CrN→α+CrN ; abaut 6～7% Cr : γ→α+γ→α+γ+Cr_2N→α+Cr_2N+CrN ; about 7～13% Cr : γ→α+γ→α+γ+Cr_2N→α+Cr_2N ; about 13～26% Cr : α+γ→α+γ+Cr_2N→α+Cr_2N ; above about 26% Cr : α→α+Cr_2N. (3) In the case of alloys containing chromium above about 13%, the minimum content of nitrogen to obtain a completely austenitic structure increased with the chromium content ; for example, the minimum nitrogen contents in 13, 18 and 16% Cr alloys were about 0.1, 0.4 and 0.8%, respectively. The microstructures of these alloys revealed such a change as γ→γ+Cr_2N→α+γ+Cr_2N→α→Cr_2N. (4) The very fine acicular phase was observed within ferrite in the Fe-Cr-N alloys, which contained chromium above about 15% and were quenched in water from above about 1100℃. It was confirmed that this phase was Cr_2N precipitated during cooling clue to a remarkable decrease of the solubility of nitrogen in ferrite, and that the suppression of this precipitation was very difficult

ドウセイアイ ト ホウリロン ショウニン ガイネン ヲ テガカリ ニ

論

Bilateral Cataract in a Cynomolgus Monkey

Severe bilateral cataract was found in a 7 year-old naïve female cynomolgus monkey (Macaca fascicularis) 3 months before necropsy. During macroscopic examination, severe opacity and thinning of the lens were observed in both eyes. Histopathology revealed that the lens nuclei and majority of cortex lens fibers had disappeared and become excavated, while the lens fibers in the subcapsular area were swollen and distorted. Other observations included atrophy and vacuolation in the lens epithelial cells and proliferation of spindle cells and collagen fiber beneath the anterior capsule of the right eye. Immunohistochemical staining of these spindle cells revealed the presence of vimentin, cytokeratin and α-smooth muscle actin (α-SMA), which were considered to be derived from lens epithelial cells. This is a rare case of spontaneous, bilateral, hypermature cataract in a cynomolgus monkey

Reactions of 6-metheoxy-3-azabicyclo[4.2.0]octan-2-one and its 7-substituted derivatives

金沢大学大学院自然科学研究科生理活性物質科学金沢大学薬学

Novel assay system for acidic Peptide:N-glycanase (aPNGase) activity in crude plant extract

Acidic peptide:N-glycanase (aPNGase) plays a pivotal role in plant glycoprotein turnover. For the construction of aPNGase-knockout or -overexpressing plants, a new method to detect the activity in crude plant extracts is required because endogenous peptidases present in the extract hamper enzyme assays using fluorescence-labeled N-glycopeptides as a substrate. In this study, we developed a new method for measuring aPNGase activity in crude extracts from plant material

Porencephaly in a Cynomolgus Monkey (Macaca Fascicularis)

Porencephaly was observed in a female cynomolgus monkey (Macaca fascicularis) aged 5 years and 7 months. The cerebral hemisphere exhibited diffuse brownish excavation with partial defects of the full thickness of the hemispheric wall, and it constituted open channels between the lateral ventricular system and arachnoid space. In addition, the bilateral occipital lobe was slightly atrophied. Histopathologically, fibrous gliosis was spread out around the excavation area and its periphery. In the roof tissue over the cavity, small round cells were arranged in the laminae. They seemed to be neural or glial precursor cells because they were positive for Musashi 1 and negative for NeuN and GFAP. In the area of fibrous gliosis, hemosiderin or lipofuscin were deposited in the macrophages, and activated astroglias were observed extensively around the excavation area