142 research outputs found

    Color Removal of Reactive Procion Dyes by Clay Adsorbents

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    AbstractThe adsorptions of reactive procion brilliant red H-EGXL and procion yellow H-EXL by various clay adsorbents were investigated in this research. The research showed that synthetic talc has the highest adsorption capacity for decolorization of both procion type of reactive dyes compared with other clay adsorbents. The removal efficiencies of synthetic talc relatively stable above 80% until the initial dye concentration reached at 160mg.L-1 of both reactive procion dyes when the liquid/solid ratio of 50mL.g-1. Synthetic talc and kaolin showed higher adsorption capacity under acidic condition than neutral and alkaline condition because of higher zeta potential. The adsorption isotherm of synthetic talc and kaolin were fitted by Langmuir adsorption isotherm that assumes that dyes molecule only formed monolayer over the homogenous surface of adsorbent

    APC/C–Cdc20-mediated degradation of cyclin B participates in CSF arrest in unfertilized Xenopus eggs

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    AbstractIn vertebrates, unfertilized eggs are arrested at meiotic metaphase II (meta-II) by cytostatic factor (CSF), with Cdc2 activity maintained at a constant, high level. CSF is thought to suppress cyclin B degradation through the inhibition of the anaphase-promoting complex/cyclosome (APC/C)-Cdc20 while cyclin B synthesis continues in unfertilized eggs. Thus, it is a mystery how Cdc2 activity is kept constant during CSF arrest. Here, we show that the APC/C–Cdc20 can mediate cyclin B degradation in CSF-arrested Xenopus eggs and extracts, in such a way that when Cdc2 activity is elevated beyond a critical level, APC/C–Cdc20-dependent cyclin B degradation is activated and Cdc2 activity consequently declines to the critical level. This feedback control of Cdc2 activity is shown to be required for keeping Cdc2 activity constant during meta-II arrest. We have also shown that Mos/MAPK pathway is essential for preventing the cyclin B degradation from inactivating Cdc2 below the critical level required to sustain meta-II arrest. Our results indicate that under CSF arrest, Mos/MAPK activity suppresses cyclin B degradation, preventing Cdc2 activity from falling below normal meta-II levels, whereas activation of APC/C–Cdc20-mediated cyclin B degradation at elevated levels of Cdc2 activity prevents Cdc2 activity from reaching excessively high levels

    First Detection of Near-Infrared Intraday Variations in the Seyfert 1 Nucleus NGC4395

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    We carried out a one-night optical V and near-infrared JHK monitoring observation of the least luminous Seyfert 1 galaxy, NGC4395, on 2004 May 1, and detected for the first time the intraday flux variations in the J and H bands, while such variation was not clearly seen for the K band. The detected J and H variations are synchronized with the flux variation in the V band, which indicates that the intraday-variable component of near-infrared continuum emission of the NGC4395 nucleus is an extension of power-law continuum emission to the near-infrared and originates in an outer region of the central accretion disk. On the other hand, from our regular program of long-term optical BVI and near-infrared JHK monitoring observation of NGC4395 from 2004 February 12 until 2005 January 22, we found large flux variations in all the bands on time scales of days to months. The optical BVI variations are almost synchronized with each other, but not completely with the near-infrared JHK variations. The color temperature of the near-infrared variable component is estimated to be T=1320-1710 K, in agreement with thermal emission from hot dust tori in active galactic nuclei (AGNs). We therefore conclude that the near-infrared variation consists of two components having different time scales, so that a small K-flux variation on a time scale of a few hours would possibly be veiled by large variation of thermal dust emission on a time scale of days.Comment: 4 pages including figures, accepted for publication in ApJ

    Multiple Regression Analysis of the Variable Component in the Near-Infrared Region for Type 1 AGN MCG+08-11-011

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    We propose a new method of analysing a variable component for type 1 active galactic nuclei (AGNs) in the near-infrared wavelength region. This analysis uses a multiple regression technique and divides the variable component into two components originating in the accretion disk at the center of AGNs and from the dust torus that far surrounds the disk. Applying this analysis to the long-term VHKVHK monitoring data of MCG+08-11-011 that were obtained by the MAGNUM project, we found that the (H−K)(H-K)-color temperature of the dust component is T=1635T = 1635K ±20\pm20K, which agrees with the sublimation temperature of dust grains, and that the time delay of KK to HH variations is Δt≈6\Delta t\approx 6 days, which indicates the existence of a radial temperature gradient in the dust torus. As for the disk component, we found that the power-law spectrum of fΜ∝Μαf_\nu \propto \nu^\alpha in the VV to near-infrared HKHK bands varies with a fixed index of α≈−0.1\alpha\approx -0.1 -- +0.4, which is broadly consistent with the irradiated standard disk model. The outer part of the disk therefore extends out to a radial distance where the temperature decreases to radiate the light in the near-infrared.Comment: 10pages + 5figures, accepted by ApJ

    Non-drug and surgical treatment algorithm and recommendations for the 2020 update of the Japan College of Rheumatology clinical practice guidelines for the management of rheumatoid arthritis—secondary publication

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    [Objectives] The aim of this study was to update the Japan College of Rheumatology (JCR) clinical practice guidelines (CPGs) for the management of rheumatoid arthritis (RA) and prepare an algorithm for non-drug and surgical treatments. This article is a digest version of the guidelines. [Methods] The Japanese Ministry of Health, Labour and Welfare’s research group, in collaboration with the JCR, used the Grading of Recommendations, Assessment, Development, and Evaluation method to update the 2014 JCR CPG for RA. The consensus was formed by CPG panel members. [Results] We raised 19 clinical questions regarding non-drug and surgical treatments for RA and developed recommendations. The treatments included exercise therapy; occupational therapy; joint injection of corticosteroids; and orthopaedic surgeries including cervical spine surgery, wrist and foot arthroplasty, ankle arthrodesis, and replacement arthroplasty of the shoulder, elbow, finger, hip, knee, and ankle. Recommendations regarding the risks of surgery and perioperative discontinuation of medications have also been developed. Based on these recommendations, we created an original algorithm for the non-drug and surgical treatment of RA. [Conclusions] These recommendations are expected to serve rheumatologists, health care professionals, and patients with RA as tools for shared decision-making to treat residual limb joint symptoms and functional impairment

    Control of PNG kinase, a key regulator of mRNA translation, is coupled to meiosis completion at egg activation

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    The oocyte-to-embryo transition involves extensive changes in mRNA translation, regulated in Drosophila by the PNG kinase complex whose activity we show here to be under precise developmental control. Despite presence of the catalytic PNG subunit and the PLU and GNU activating subunits in the mature oocyte, GNU is phosphorylated at Cyclin B/CDK1sites and unable to bind PNG and PLU. In vitro phosphorylation of GNU by CyclinB/CDK1 blocks activation of PNG. Meiotic completion promotes GNU dephosphorylation and PNG kinase activation to regulate translation. The critical regulatory effect of phosphorylation is shown by replacement in the oocyte with a phosphorylation-resistant form of GNU, which promotes PNG-GNU complex formation, elevation of Cyclin B, and meiotic defects consistent with premature PNG activation. After PNG activation GNU is destabilized, thus inactivating PNG. This short-lived burst in kinase activity links development with maternal mRNA translation and ensures irreversibility of the oocyteto- embryo transition.National Institutes of Health (U.S.) (GM39341)National Institutes of Health (U.S.) (GM118098

    Astronomical Distance Determination in the Space Age: Secondary Distance Indicators

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    The formal division of the distance indicators into primary and secondary leads to difficulties in description of methods which can actually be used in two ways: with, and without the support of the other methods for scaling. Thus instead of concentrating on the scaling requirement we concentrate on all methods of distance determination to extragalactic sources which are designated, at least formally, to use for individual sources. Among those, the Supernovae Ia is clearly the leader due to its enormous success in determination of the expansion rate of the Universe. However, new methods are rapidly developing, and there is also a progress in more traditional methods. We give a general overview of the methods but we mostly concentrate on the most recent developments in each field, and future expectations. © 2018, The Author(s)

    MPF, starfish oocyte and cell-free extract in the background - an interview with Takeo Kishimoto

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    International audienceProfessor Takeo Kishimoto's research has an enormous impact on the cell cycle field. Although his favorite model has always been a starfish oocyte, he has used many other model organisms in his research. Cell-free extracts have been wildly used in his laboratory as a very useful tool to answer cell cycle research questions. Recently, professor Kishimoto discovered the identity of the M-phase promoting factor (MPF) that was thought for years to be cyclin-dependent kinase 1 (CDK1). However, Takeo Kishimoto found that MPF consists in fact of two kinases: CDK1 and Greatwall kinase. While CDK1 phosphorylates mitotic substrates, Greatwall kinase allows these substrates to persist in their phosphorylated state because it regulates phosphatase PP2A, which dephosphorylates the majority of CDK1 substrates. When I started to interview Prof. Kishimoto, I was mostly interested in his experiences with cell-free extracts. However, as you will see below we almost immediately turned to the problem of the identity of MPF. This is fully understandable because the identity of MPF seems to be a major interest in Takeo's scientific career. I hope readers will enjoy this interview and will be able to learn about many aspects of scientific research, which do not usually appear in regular research papers
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