542 research outputs found

    Quantum Unipotent Subgroup and dual canonical basis

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    Geiss-Leclerc-Schroer defined the cluster algebra structure on the coordinate ring C[N(w)]C[N(w)] of the unipotent subgroup, associated with a Weyl group element ww and they proved cluster monomials are contained in Lusztig's dual semicanonical basis SS^{*}. We give a set up for the quantization of their results and propose a conjecture which relates the quantum cluster algebras to the dual canonical basis Bup{B}^{up}. In particular, we prove that the quantum analogue Oq[N(w)]O_{q}[N(w)] of C[N(w)]{C}[N(w)] has the induced basis from Bup{B}^{up}, which contains quantum flag minors and satisfies a factorization property with respect to the `qq-center' of Oq[N(w)]O_{q}[N(w)]. This generalizes Caldero's results from ADE cases to an arbitary symmetrizable Kac-Moody Lie algebra.Comment: 41 page

    Polymorphonuclear leukocyte lysosomal proteases, cathepsins B and D affect the fibrinolytic system in human umbilical vein endothelial cells

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    AbstractTo clarify the physiological role played by neutrophil lysosomal protease in cultured human umbilical vein endothelial cells (HUVEC), we studied the effects of cathepsins B and D released from activated polymorphonuclear leukocytes on the fibrinolytic system in HUVEC. Cathepsins B and D reduced the antigens of tissue-type plasminogen activator, and they increased both the antigens and the activity of plasminogen activator inhibitor-1. These results suggest that cathepsins B and D are involved in the thrombotic tendency, since they inhibited the fibrinolytic system in cultured HUVEC

    Effects of Ginsenoside Rb1 on Skin Changes

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    Ginseng roots (Panax ginseng CA Meyer) have been used traditionally for the treatment, especially prevention, of various diseases in China, Korea, and Japan. Both experimental and clinical studies suggest ginseng roots to have pharmacological effects in patients with life-style-related diseases such as non-insulin-dependent diabetic mellitus, atherosclerosis, hyperlipidemia, and hypertension. The topical use of ginseng roots to treat skin complaints including atopic suppurative dermatitis, wounds, and inflammation is also described in ancient Chinese texts; however, there have been relatively few studies in this area. In the present paper, we describe introduce the biological and pharmacological effects of ginsenoside Rb1 isolated from Red ginseng roots on skin damage caused by burn-wounds using male Balb/c mice (in vivo) and by ultraviolet B irradiation using male C57BL/6J and albino hairless (HR-1) mice (in vivo). Furthermore, to clarify the mechanisms behind these pharmacological actions, human primary keratinocytes and the human keratinocyte cell line HaCaT were used in experiments in vitro

    REMARKS ON QUANTUM UNIPOTENT SUBGROUP AND DUAL CANONICAL BASIS

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    Abstract. We prove the tensor product decomposition of the half of quantized universal enveloping algebra associated with a Weyl group element which was conjectured by Berenstein and Greenstein [3, Conjecture 5.5] using the theory of the dual canonical basis

    Conservation paleobiology on Minami-Daito Island, Okinawa, Japan: anthropogenic extinction of cave-dwelling bats on a tropical oceanic island

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    Altres ajuts: CERCA Programme/Generalitat de CatalunyaWith strong environmental and geographic filtration, vertebrates incapable of flying and swimming are often extirpated from island ecosystems. Minami-Daito Island is an oceanic island in Okinawa, Japan that harbors the Daito flying fox (Pteropus dasymallus daitoensis), a subspecies of the fruit bat and the only extant mammal endemic to the island. However, the skeleton of a cave-dwelling bat Rhinolophus sp. and fossil guano were briefly reported in a previous study. Here, we present evidence for the anthropogenic extirpation of two species of cave-dwelling bats (Miniopterus sp. & Rhinolophus sp.) from Minami-Daito Island. Our goal is to reliably constrain the ages of the extirpated bat species by a multiproxy approach. Because skeletal materials did not preserve sufficient bone collagen for direct radiocarbon dating, we alternatively examined guano-like deposits based n SEM observation and Fourier-transform infrared spectroscopy (FTIR) along with stable carbon and nitrogen isotope analyses for possible indirect dating. We also examined stable carbon isotopes in bone apatite, assuming that an isotopic signal of C4 plants on the bat bones links to sugarcane plantation on the island based on the historical knowledge that early human settlers quickly replaced the island's native C3 forests with sugarcane (C4 perennial grass) plantation from 1900 onward. Our cave survey documents the remains of Miniopterus sp. from the island for the first time. Based on the unique taphonomic conditions (unpermineralized bones, disarticulated skeletons closely scattered without sediment cover, various degrees of calcite crystal growth around bones) and a radiocarbon age of a humic sample, we suggest that the maximum age constraint of Miniopterus sp. and Rhinolophus sp. is 4,640 calBP. Based on a series of analyses, we conclude that the guano-like deposits are composed not of bat guano but mainly of humic substances; however, a hydroxyapatite crust associated with bat-lying stalagmites may be derived from bat feces. Stable carbon isotope analysis of bone apatite revealed C4 signals in various degrees, confirming that small populations of cave-dwelling bats persisted on Minami-Daito Island after 1900. The results of this study indicate that these populations remained rather small and did not leave many generations and that the estimated ages can be bracketed from 4,640 calBP to the post-1900 (perhaps, until the 1950s). They likely faced a continuously high mortality risk due to severe anthropogenic stresses on the island, where most of the forests were turned into sugarcane plantations within a few decades in the early 20th century. A result of hearing surveys to local residents suggests the latest remnants most likely disappeared on the island concurrently with the introduction of chemical pesticides after World War II

    THE OPHTHALMIC ARTERY ARISING FROM THE MIDDLE MENINGEAL ARTERY

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    The present report describes a case of variation of the ophthalmic artery observed in a 91-year-old Japanese woman at dissection in 1992. It was found that on one side, the ophthalmic artery originate from the middle meningeal artery, and the ophthalmic artery from the internal carotid artery was absent
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