221 research outputs found

    SYNTHESIS OF 2,3,9,10-TETRAOXYGENATED BENZO[c]PHENANTHRIDINE DERIVATIVES VIA PALLADIUM-MEDIATED ARYL-ARYL COUPLING REACTION

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    Two 2,3,9,10-tetraoxygenated benzo[c]phenanthridine alkaloids, 1 2, originally reported as zanthoxyline and broussonpapyrine, respectively, were synthesized using the Pd-mediated intramolecular aryl-aryl coupling reaction as the key step

    北部オマーンおよびリザード・オフィオライトのマントル部の岩石学的性質 : 露岩および砕屑性クロムスピネルからのアプローチ

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    取得学位:博士(理学),学位授与番号:博甲第491号,学位授与年月日:平成14年3月22日,学位授与年:200

    Duite-Wehrlite-Olivine Clinopyroxenite Series Rocks from the North Fiji Basin : Precious Deep-Seated Rocks from the Backarc Basin

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    金沢大学大学院自然科学研究科Deep Ocean Resources Development CO.,LTD.Promoting Environmental Pesearch in Pan-Japan Sea Area : Young Researchers\u27 Network, Schedule: March 8-10,2006,Kanazawa Excel Hotel Tokyu, Japan, Organized by: Kanazawa University 21st-Century COE Program, Environmental Monitoring and Prediction of Long- & Short- Term Dynamics of Pan-Japan Sea Area ; IICRC(Ishikawa International Cooperation Research Centre), Sponsors : Japan Sea Research ; UNU-IAS(United Nations University Institute of Advanced Studies)+Ishikawa Prefecture Government ; City of Kanazaw

    Chemical characteristics of chromian spinel in plutonic rocks: Implications for deep magma processes and discrimination of tectonic setting

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    金沢大学理工研究域自然システム学系We summarize chemical characteristics of chromian spinels from ultramafic to mafic plutonic rocks (lherzolites, harzburgites, dunites, wehrlites, troctolites, olivine gabbros) with regard to three tectonic settings (mid-ocean ridge, arc, oceanic hotspot). The chemical range of spinels is distinguishable between the three settings in terms of Cr# (=Cr/(Cr+Al) atomic ratio) and Ti content. The relationships are almost parallel with those of chromian spinels in volcanic rocks, but the Ti content is slightly lower in plutonics than in volcanics at a given tectonic environment. The Cr# of spinels in plutonic rocks is highly diverse; its ranges overlap between the three settings, but extend to higher values (up to 0.8) in arc and oceanic hotspot environments. The Ti content of spinels in plutonics increases, for a given lithology, from the arc to oceanic hotspot settings by mid-ocean ridge on average. This chemical diversity is consistent with that of erupted magmas from the three settings. If we systematically know the chemistry of chromian spinels from a series of plutonic rocks, we can estimate their tectonic environments of formation. The spinel chemistry is especially useful in dunitic rocks, in which chromian spinel is the only discriminating mineral. Applying this, discordant dunites cutting mantle peridotites were possibly precipitated from arc-related magmas in the Oman ophiolite, and from an intraplate tholeiite in the Lizard ophiolite, Cornwall. © 2010 Blackwell Publishing Asia Pty Ltd

    Petrology of the Yugu peridotites in the Gyeonggi Massif, South Korea: Implications for its origin and hydration process

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    金沢大学理工研究域自然システム学系Peridotites exposed in the Yugu area in the Gyeonggi Massif, South Korea, near the boundary with the Okcheon Belt, exhibit mylonitic to strongly porphyroclastic textures, and are mostly spinel lherzolites. Subordinate dunites, harzburgites, and websterites are associated with the lherzolites. Amphiboles, often zoned from hornblende in the core to tremolite in the rim, are found only as neoblasts. Porphyroclasts have recorded equilibrium temperatures of about 1000°C, whereas neoblasts denote lower temperatures, about 800°C. Olivines are Fo 90-91 in lherzolites and Fo 91 in a dunite and a harzburgite. The Cr# (=Cr/(Cr + Al) atomic ratio) of spinels varies together with the Fo of olivines, being from 0.1 to 0.3 in lherzolites and around 0.5 in the dunite and harzburgite. The Na2O content of clinopyroxene porphyroclasts is relatively low, around 0.3 to 0.5 wt% in the most fertile lherzolite. The Yugu peridotites are similar in porphyroclast mineral chemistry not to continental spinel peridotites but to sub-arc or abyssal peridotites. Textural and mineralogical characteristics indicate the successive cooling with hydration from the upper mantle to crustal conditions for the Yugu peridotites. Almost all clinopyroxenes and amphiboles show the same U-shaped rare earth element (REE) patterns although the level is up to ten times higher for the latter. The hydration was associated with enrichment in light REE, resulting from either a slab-derived fluid or a fluid circulating in the crust. The mantle-wedge or abyssal peridotites were emplaced into the continental crust as the Yugu peridotite body during collision of continents to form a high-pressure metamorphic belt in the Gyeonggi Massif. The peridotites from the Gyeonggi Massif exhibit lower-pressure equilibration than peridotites, with or without garnets, from the Dabie-Sulu Collision Belt, China, which is possibly a westward extension of the Gyeonggi Massif. © 2008 The Authors Journal compilation © 2008 Blackwell Publishing Asia Pty Ltd

    Functional anterior pituitary generated in self-organizing culture of human embryonic stem cells

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    Anterior pituitary is critical for endocrine systems. Its hormonal responses to positive and negative regulators are indispensable for homeostasis. For this reason, generating human anterior pituitary tissue that retains regulatory hormonal control in vitro is an important step for the development of cell transplantation therapy for pituitary diseases. Here we achieve this by recapitulating mouse pituitary development using human embryonic stem cells. We find that anterior pituitary self-forms in vitro following the co-induction of hypothalamic and oral ectoderm. The juxtaposition of these tissues facilitated the formation of pituitary placode, which subsequently differentiated into pituitary hormone-producing cells. They responded normally to both releasing and feedback signals. In addition, after transplantation into hypopituitary mice, the in vitro-generated corticotrophs rescued physical activity levels and survival of the hosts. Thus, we report a useful methodology for the production of regulator-responsive human pituitary tissue that may benefit future studies in regenerative medicine

    Human iPSC-Derived Cerebral Organoids Model Cellular Features of Lissencephaly and Reveal Prolonged Mitosis of Outer Radial Glia

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    Classical lissencephaly is a genetic neurological disorder associated with mental retardation and intractable epilepsy, and Miller-Dieker syndrome (MDS) is the most severe form of the disease. In this study, to investigate the effects of MDS on human progenitor subtypes that control neuronal output and influence brain topology, we analyzed cerebral organoids derived from control and MDS-induced pluripotent stem cells (iPSCs) using time-lapse imaging, immunostaining, and single-cell RNA sequencing. We saw a cell migration defect that was rescued when we corrected the MDS causative chromosomal deletion and severe apoptosis of the founder neuroepithelial stem cells, accompanied by increased horizontal cell divisions. We also identified a mitotic defect in outer radial glia, a progenitor subtype that is largely absent from lissencephalic rodents but critical for human neocortical expansion. Our study, therefore, deepens our understanding of MDS cellular pathogenesis and highlights the broad utility of cerebral organoids for modeling human neurodevelopmental disorders

    Organs to Cells and Cells to Organoids: The Evolution of in vitro Central Nervous System Modelling

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    With 100 billion neurons and 100 trillion synapses, the human brain is not just the most complex organ in the human body, but has also been described as “the most complex thing in the universe.” The limited availability of human living brain tissue for the study of neurogenesis, neural processes and neurological disorders has resulted in more than a century-long strive from researchers worldwide to model the central nervous system (CNS) and dissect both its striking physiology and enigmatic pathophysiology. The invaluable knowledge gained with the use of animal models and post mortem human tissue remains limited to cross-species similarities and structural features, respectively. The advent of human induced pluripotent stem cell (hiPSC) and 3-D organoid technologies has revolutionised the approach to the study of human brain and CNS in vitro, presenting great potential for disease modelling and translational adoption in drug screening and regenerative medicine, also contributing beneficially to clinical research. We have surveyed more than 100 years of research in CNS modelling and provide in this review an historical excursus of its evolution, from early neural tissue explants and organotypic cultures, to 2-D patient-derived cell monolayers, to the latest development of 3-D cerebral organoids. We have generated a comprehensive summary of CNS modelling techniques and approaches, protocol refinements throughout the course of decades and developments in the study of specific neuropathologies. Current limitations and caveats such as clonal variation, developmental stage, validation of pluripotency and chromosomal stability, functional assessment, reproducibility, accuracy and scalability of these models are also discussed
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