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  • 1
    Publication Date: 2015-05-13
    Description: High-pressure polymorphs recovered in terrestrial craters are evidence of meteoroid impact events on the Earth’s surface. Despite countless impact craters on the Moon, high-pressure polymorphs have not been reported to date in returned Apollo samples. On the other hand, recent studies report that the high-pressure polymorphs of silica, coesite, and stishovite occur in shocked lunar meteorites. We investigated regolith breccia 15299, which was returned by the Apollo 15 mission, using the combined techniques of focused ion beam (FIB), synchrotron X-ray diffraction (XRD), and transmission electron microscopy (TEM). The regolith breccia 15299 studied here consists of a mafic impact melt breccia with millimeter-sized, coarse-grained, low-Ti basalt clasts. The mafic melt breccia consists of fragments of minerals (olivine, pyroxene, plagioclase, silica, and ilmenite) and glass. Several quartz, tridymite, and cristobalite grains of 10–100 μm across occur in the mafic impact melt breccia. Vesicular melt veins of less than ~200 μm wide cut across the mafic melt breccia matrix and mineral fragments. Some silica grains are entrained in the melt veins. One of the silica grains entrained in the melt veins consist of stishovite [ a = 4.190(1), c = 2.674(1) Å, V = 46.95 Å 3 , space group P 4 2 / mnm ] along with tridymite and silica glass. This is the first report of high-pressure polymorphs from returned lunar samples. TEM images show that the stishovite is needle-like in habit, and up to ~400 nm in size. Considering the lithologies and shock features of 15299, it is inferred that the stishovite possibly formed by the Imbrium impact or subsequent local impact event(s) in the Procellarum KREEP Terrane (PKT) of the nearside of the Moon.
    Print ISSN: 0003-004X
    Electronic ISSN: 1945-3027
    Topics: Geosciences
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  • 2
    Publication Date: 2011-04-13
    Description: We report evidence for the natural dissociation of olivine in a shergottite at high-pressure and high-temperature conditions induced by a dynamic event on Mars. Olivine (Fa34-41) adjacent to or entrained in the shock melt vein and melt pockets of Martian meteorite olivine-phyric shergottite Dar al Gani 735 dissociated into (Mg,Fe)SiO3 perovskite (Pv)+magnesiowüstite (Mw), whereby perovskite partially vitrified during decompression. Transmission electron microscopy observations reveal that microtexture of olivine dissociation products evolves from lamellar to equigranular with increasing temperature at the same pressure condition. This is in accord with the observations of synthetic samples recovered from high-pressure and high-temperature experiments. Equigranular (Mg,Fe)SiO3 Pv and Mw have 50–100 nm in diameter, and lamellar (Mg,Fe)SiO3 Pv and Mw have approximately 20 and approximately 10 nm in thickness, respectively. Partitioning coefficient, KPv/Mw = [FeO/MgO]/[FeO/MgO]Mw, between (Mg,Fe)SiO3 Pv and Mw in equigranular and lamellar textures are approximately 0.15 and approximately 0.78, respectively. The dissociation of olivine implies that the pressure and temperature conditions recorded in the shock melt vein and melt pockets during the dynamic event were approximately 25 GPa but 700 °C at least.
    Print ISSN: 0027-8424
    Electronic ISSN: 1091-6490
    Topics: Biology , Medicine , Natural Sciences in General
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  • 3
    Publication Date: 2014-03-22
    Description: The development of cells specialized for water conduction or support is a striking innovation of plants that has enabled them to colonize land. The NAC transcription factors regulate the differentiation of these cells in vascular plants. However, the path by which plants with these cells have evolved from their nonvascular ancestors is unclear. We investigated genes of the moss Physcomitrella patens that encode NAC proteins. Loss-of-function mutants formed abnormal water-conducting and supporting cells, as well as malformed sporophyte cells, and overexpression induced ectopic differentiation of water-conducting-like cells. Our results show conservation of transcriptional regulation and cellular function between moss and Arabidopsis thaliana water-conducting cells. The conserved genetic basis suggests roles for NAC proteins in the adaptation of plants to land.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Xu, Bo -- Ohtani, Misato -- Yamaguchi, Masatoshi -- Toyooka, Kiminori -- Wakazaki, Mayumi -- Sato, Mayuko -- Kubo, Minoru -- Nakano, Yoshimi -- Sano, Ryosuke -- Hiwatashi, Yuji -- Murata, Takashi -- Kurata, Tetsuya -- Yoneda, Arata -- Kato, Ko -- Hasebe, Mitsuyasu -- Demura, Taku -- New York, N.Y. -- Science. 2014 Mar 28;343(6178):1505-8. doi: 10.1126/science.1248417. Epub 2014 Mar 20.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/24652936" target="_blank"〉PubMed〈/a〉
    Keywords: Adaptation, Physiological/*genetics ; Amino Acid Sequence ; Arabidopsis/genetics/*physiology ; Bryopsida/genetics/*physiology ; *Gene Expression Regulation, Plant ; Genetic Loci ; Genome, Plant ; Molecular Sequence Data ; Plant Proteins/genetics/*physiology ; Plant Stems/growth & development ; Trans-Activators/genetics/*physiology ; Transcription, Genetic ; Water/*physiology
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 4
    Publication Date: 2009-12-22
    Description: Innate immune responses are important in combating various microbes during the early phases of infection. Natural killer (NK) cells are innate lymphocytes that, unlike T and B lymphocytes, do not express antigen receptors but rapidly exhibit cytotoxic activities against virus-infected cells and produce various cytokines. Here we report a new type of innate lymphocyte present in a novel lymphoid structure associated with adipose tissues in the peritoneal cavity. These cells do not express lineage (Lin) markers but do express c-Kit, Sca-1 (also known as Ly6a), IL7R and IL33R. Similar lymphoid clusters were found in both human and mouse mesentery and we term this tissue 'FALC' (fat-associated lymphoid cluster). FALC Lin(-)c-Kit(+)Sca-1(+) cells are distinct from lymphoid progenitors and lymphoid tissue inducer cells. These cells proliferate in response to IL2 and produce large amounts of T(H)2 cytokines such as IL5, IL6 and IL13. IL5 and IL6 regulate B-cell antibody production and self-renewal of B1 cells. Indeed, FALC Lin(-)c-Kit(+)Sca-1(+) cells support the self-renewal of B1 cells and enhance IgA production. IL5 and IL13 mediate allergic inflammation and protection against helminth infection. After helminth infection and in response to IL33, FALC Lin(-)c-Kit(+)Sca-1(+) cells produce large amounts of IL13, which leads to goblet cell hyperplasia-a critical step for helminth expulsion. In mice devoid of FALC Lin(-)c-Kit(+)Sca-1(+) cells, such goblet cell hyperplasia was not induced. Thus, FALC Lin(-)c-Kit(+)Sca-1(+) cells are T(H)2-type innate lymphocytes, and we propose that these cells be called 'natural helper cells'.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Moro, Kazuyo -- Yamada, Taketo -- Tanabe, Masanobu -- Takeuchi, Tsutomu -- Ikawa, Tomokatsu -- Kawamoto, Hiroshi -- Furusawa, Jun-Ichi -- Ohtani, Masashi -- Fujii, Hideki -- Koyasu, Shigeo -- England -- Nature. 2010 Jan 28;463(7280):540-4. doi: 10.1038/nature08636. Epub 2009 Dec 20.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Microbiology and Immunology, Keio University School of Medicine, Shinjuku-ku, Tokyo 160-8582, Japan.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20023630" target="_blank"〉PubMed〈/a〉
    Keywords: Adipose Tissue/*cytology/*immunology ; Animals ; Antigens, Ly/genetics/*immunology/metabolism ; B-Lymphocytes/cytology/immunology ; Cell Proliferation ; Cytokines/*immunology ; *Gene Expression Regulation ; Humans ; Lymphocytes/*immunology ; Membrane Proteins/genetics/*immunology ; Mesentery/immunology ; Mice ; Mice, Inbred C57BL ; Nematoda/physiology ; Nematode Infections/immunology ; Proto-Oncogene Proteins c-kit/genetics/*immunology ; Th2 Cells/immunology
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 5
    Publication Date: 2013-07-14
    Description: The melting and phase relations of carbonated MORB eclogite have been investigated using the multi-anvil technique at 9–21 GPa and 1100–1900°C. The starting compositions were two synthetic mixes, GA1 and Volga, with the CO 2 component added as CaCO 3 (cc): GA1 + 10%cc (GA1cc) models altered oceanic crust recycled into the convecting mantle via subduction, and Volga + 10%cc (Volga-cc) models subducted oceanic crust that has lost some of its siliceous component in the sub-arc regime (GA1 minus 6·5 wt % SiO 2 ). The subsolidus mineral assemblage at 9 and 13 GPa includes garnet, clinopyroxene, magnesite, aragonite, a high-pressure polymorph of TiO 2 (only at 9 GPa) and stishovite (only at 13 GPa). At 17–21 GPa clinopyroxene is no longer stable; the mineral assemblage consists predominantly of garnet with subordinate magnesite (only at 17 GPa), Na-rich aragonite, stishovite, Ca-perovskite (mostly at 21 GPa), and K-hollandite (mostly at 17 GPa). Na-carbonate with an inferred composition (Na,K) 2 (Ca,Mg,Fe)(CO 3 ) 2 was present in Volga-cc at 21 GPa and 1200°C. Diamond (or graphite) crystallized in most runs in the GA1cc composition, but it was absent in experiments with the Volga-cc composition. In Volga-cc, the solidus temperatures are nearly constant between 1200 and 1300°C over the entire pressure range investigated. In GA1cc, the solidus is located at similar temperatures at 9–13 GPa, but at higher temperatures of 1300–1500°C at 17–21 GPa. The difference in solidi between the GA1cc and Volga-cc compositions can be explained by a change in Na compatibility between 13 and 17 GPa as omphacitic clinopyroxene disappears, resulting in the formation of Na-carbonate or Na-rich melt in Volga-cc. The solidus temperature in GA1cc also increases with increasing pressure as a consequence of carbonate reduction and diamond precipitation, possibly brought on either via progressive Fe 2+ –Fe 3+ transition in garnet at higher pressures or by a decrease of the activity of the diopside component in clinopyroxene. The low-degree melts are highly alkalic (K-rich at 9–13 GPa and Na-rich at 17–21 GPa) carbonatites, changing towards SiO 2 -rich melts with increasing temperature at constant pressure. The solidi of both compositions remain higher than typical subduction pressure–temperature ( P–T ) profiles at 5–10 GPa; however, at higher pressures the flat solidus curve of carbonated eclogite may intersect the subduction P–T profile in the Transition Zone, where carbonated eclogite can produce alkali- and carbonate-rich melts. Such subduction-related alkali-rich melts can be potential analogues of kimberlite and carbonatite melt compositions and important agents of mantle metasomatism and diamond formation in the Transition Zone and in cratonic roots. Melting of carbonated eclogite produces a garnet-bearing refractory residue, which could be stored in the Transition Zone or lower mantle.
    Print ISSN: 0022-3530
    Electronic ISSN: 1460-2415
    Topics: Geosciences
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  • 6
    Publication Date: 1986-02-21
    Description: A 4-week assay for screening tumor promoters of bladder cancer has been developed in which increased agglutinability of isolated rat bladder cells with concanavalin A is used as an indicator. On the basis of this assay system, L-isoleucine and L-leucine were suspected of being possible tumor promoters. Results of 40- to 60-week carcinogenesis experiments in which N-butyl-N-(4-hydroxybutyl)nitrosamine was used as an initiator demonstrate that L-isoleucine and L-leucine promote bladder cancer in rats. This finding may be relevant to the high incidence of human bladder cancer in Western countries, where the diet is rich in protein.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Nishio, Y -- Kakizoe, T -- Ohtani, M -- Sato, S -- Sugimura, T -- Fukushima, S -- New York, N.Y. -- Science. 1986 Feb 21;231(4740):843-5.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3945812" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; *Carcinogens ; Carcinoma/*chemically induced ; *Isoleucine ; *Leucine ; Papilloma/*chemically induced ; Precancerous Conditions/*chemically induced ; Rats ; Rats, Inbred F344 ; Urinary Bladder Neoplasms/*chemically induced
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 7
    Publication Date: 2016-09-14
    Description: Vitamin C deficiency is found in patients with cancer and might complicate various therapy paradigms. Here we show how this deficiency may influence the use of DNA methyltransferase inhibitors (DNMTis) for treatment of hematological neoplasias. In vitro, when vitamin C is added at physiological levels to low doses of the...
    Keywords: Inaugural Articles
    Print ISSN: 0027-8424
    Electronic ISSN: 1091-6490
    Topics: Biology , Medicine , Natural Sciences in General
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  • 8
    Publication Date: 2014-07-30
    Description: Howardite–eucrite–diogenite meteorites (HEDs) probably originated from the asteroid 4 Vesta. We investigated one eucrite, Béréba, to clarify a dynamic event that occurred on 4 Vesta using a shock-induced high-pressure polymorph. We discovered high-pressure polymorphs of silica, coesite, and stishovite originating from quartz and/or cristobalite in and around the shock-melt veins...
    Print ISSN: 0027-8424
    Electronic ISSN: 1091-6490
    Topics: Biology , Medicine , Natural Sciences in General
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  • 9
    ISSN: 0378-4347
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Journal of Physics and Chemistry of Solids 35 (1974), S. 585-589 
    ISSN: 0022-3697
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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