107 research outputs found

    BASIC MAGNETIC PROPERTIES OF AMORPHOUS ALLOYS

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    The present state of knowledge and understanding of the basic magnetic properties of amorphous alloys is reviewed. It covers magnetic moment, exchange interaction and temperature dependence of the magnetization for both categories; metal - metalloid and rare earth-transition metal amorphous alloys. It is pointed out that the effect of electron transfer on the magnetic moment of transition metal atoms and the effect of fluctuation of exchange interaction on the temperature dependence of the magnetization is characteristic in amorphous alloy systems

    FERRIMAGNETISM IN AMORPHOUS ALLOYS

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    The characteristic aspects of ferrimagnetism in amorphous alloys, the subnetwork magnetization, anisotropy from dipolar interactions and exchange stiffness are discussed

    Biosynthesis of unnatural glycolipids possessing diyne moiety in the acyl chain in the green sulfur photosynthetic bacterium Chlorobaculum tepidum grown by supplementation of 10,12-heptadecadiynic acid

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    AbstractUnnatural glycolipids possessing the diyne moiety in their acyl groups were successfully biosynthesized in the green sulfur photosynthetic bacterium Chlorobaculum (Cba.) tepidum by cultivation with supplementation of 10,12-heptadecadiynic acid. Monogalactosyldiacylglycerol (MGDG) and rhamnosylgalactosyldiacylglycerol (RGDG) esterified with one 10,12-heptadecadiynic acid were primarily formed in the cells, and small amounts of glycolipids esterified with the two unnatural fatty acids can also be detected. The relative ratio of these unnatural glycolipids occupied in the total glycolipids was estimated to be 49% based on HPLC analysis using a evaporative light scattering detector. These results indicate that the acyl groups in glycolipids, which play important roles in the formation of extramembranous antenna complexes called chlorosomes, can be modified in vivo by cultivation of green sulfur photosynthetic bacteria with exogenous synthetic fatty acids. Visible absorption and circular dichroism spectra of Cba. tepidum containing the unnatural glycolipids demonstrated the formation of chlorosomes, indicating that the unnatural glycolipids in this study did not interfere with the biogenesis of chlorosomes

    Plexiform neurofibroma in the hepatic hilum associated with neurofibromatosis type 1: a case report

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    We present an extremely rare case of plexiform neurofibroma involving the hepatic hilum. A 24-year old woman who had been diagnosed with neurofibromatosis type 1 was referred to our hospital for evaluation of an abdominal mass found on computed tomography and progressive aggravation of intermittent abdominal pain. Abdominal computed tomography revealed a multilobulated non-enhancing mass involving the celiac trunk and hepatic artery, that extended to the hepatic hilum through the hepatoduodenal ligament. Magnetic resonance imaging showed the lesion extending along the intrahepatic Glisson's sheath. Based on the imaging findings, the patient was diagnosed to have a neu-rofibroma, although sarcomatous differentiation could not be excluded. The tumor was resected, leaving behind the intrahepatic extension, with the aim of alleviating the abdominal pain and preventing obstructive jaundice. Histopathological examination revealed the diagnosis of plexiform neurofibroma. At present, three years after the surgery, the patient remains symptom-free, without any evidence of recurrence

    Malignant Triton tumor in the retroperitoneal space associated with neurofibromatosis type 1: a case study

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    We report an extremely rare case of malignant Triton tumor developing in the retroperitoneal space in a patient with neurofibromatosis type 1. A 21-year old man who had been diagnosed with neurofibromatosis type 1 was admitted to our hospital with the chief complaint of a palpable abdominal mass. Abdominal computed tomography revealed a huge heterogeneous tumor measuring approximately 17 cm in diameter occupying the left retroperitoneal space, and numerous metastatic lesions between the left psoas muscle and the left thigh with dissolution of the left hip joint. After the diagnosis of a retroperitoneal malignant neurogenic tumor, resection of the tumor with reconstruction of the abdominal aorta was conducted, followed by postoperative transarterial infusion chemotherapy. The histopathological diagnosis was malignant peripheral nerve sheath tumor with rhabdomyosarcomatous differentiation, namely malignant Triton tumor. Postoperative chemotherapy was in vain and the patient died 14 months after the surgery as a result of lung metastasis

    Comunidade de Colêmbolos em florestas decíduas e em plantações da conífera Cryptomeria japonica no Japão central

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    Collembolan communities in conifer plantations (Japanese cedar, Cryptomeria japonica) and secondary deciduous broad-leaved forests of varying ages were investigated to determine the extent to which forest conversion (broad-leaved to coniferous) affects the species richness and assemblage composition of Collembola in central Japan. Density and total species richness of Collembola not differed between the broad-leaved and cedar forests except immediately after clear-cutting. The amount of forest-floor organic matter was larger in cedar forests and positively correlated with the species richness of detritus feeders. Species richness of fungal feeders and sucking feeders positively correlated with the species richness of forest-floor plants. There was difference in collembolan species composition between the forest types. The age of the forests seemed to have only small importance for the collembolan community, except during the first four years after clear-cutting. The conversion to artificial cedar stands has not reduced the abundance or species richness of collembolan communities, but has affected community composition. Differences in species composition may be related to the ground floras.As comunidades de colÛmbolos nas plantaþ§es da conÝfera Cryptomeria japonica (cedro japonês) e florestas decíduas secundárias de várias idades foram investigadas para determinar até que ponto a conversão da floresta decídua em conífera afeta a riqueza das espécies e a composição das comunidades de colêmbolos no Japão central. A densidade e a riqueza total de espécies de Collembola não foram diferentes entre as florestas decíduas e de cedro, exceto imediatamente depois do corte raso. A quantidade de matéria orgânica acumulada no solo foi maior sob cedro e positivamente correlacionada com a riqueza de espécies de detritívoros. A riqueza de espécies de fungívoros e sugadores foi positivamente correlacionada à riqueza de espécies de plantas do estrato herbáceo da floresta. Houve diferença na composição das espécies de colêmbolos entre os tipos de floresta. A idade das florestas parece ter pouca importância para a comunidade de colêmbolos, exceto nos primeiros quatro anos após o corte raso. Concluiu-se que a conversão da floresta decídua em plantações de cedro japonês não causou diminuição na abundância e na riqueza das espécies das comunidades de colêmbolos, mas afetou a composição dessas comunidades. As diferenças na composição das espécies podem ser relacionadas ao desenvolvimento de plantas do estrato herbáceo da floresta

    Identification of cell cycle–arrested quiescent osteoclast precursors in vivo

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    Osteoclasts are multinucleated cells that resorb bone. Although osteoclasts originate from the monocyte/macrophage lineage, osteoclast precursors are not well characterized in vivo. The relationship between proliferation and differentiation of osteoclast precursors is examined in this study using murine macrophage cultures treated with macrophage colony-stimulating factor (M-CSF) and receptor activator of NF-κB (RANK) ligand (RANKL). Cell cycle–arrested quiescent osteoclast precursors (QuOPs) were identified as the committed osteoclast precursors in vitro. In vivo experiments show that QuOPs survive for several weeks and differentiate into osteoclasts in response to M-CSF and RANKL. Administration of 5-fluorouracil to mice induces myelosuppression, but QuOPs survive and differentiate into osteoclasts in response to an active vitamin D3 analogue given to those mice. Mononuclear cells expressing c-Fms and RANK but not Ki67 are detected along bone surfaces in the vicinity of osteoblasts in RANKL-deficient mice. These results suggest that QuOPs preexist at the site of osteoclastogenesis and that osteoblasts are important for maintenance of QuOPs
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