340 research outputs found
Observation of machined surface and subsurface structure of hinoki (Chamaecyparis obtusa) produced in slow-speed orthogonal cutting using X-ray computed tomography
First online: 01 January 2015X-ray computed tomography (CT) was applied to non-destructive observation of machined surface and subsurface structure of hinoki (Chamaecyparis obtusa) produced in slow-speed orthogonal cutting. The cutting experiments were conducted under several cutting conditions and the chip formations were observed with a high-speed camera to be classified into four chip types. The difference in the quality of the machined surfaces produced in four types of chip formation was investigated. During type 0 chip formation, the workpiece was cut almost exactly at the path of the cutting edge, so no deformation was found on and beneath the machined surface. During type I chip formation, the direction of the fore-split, which is dependent on the arrangement of cells, determined the machined surface. During type II chip formation, the cutting tool sometimes tore part of the workpiece below the path of the cutting edge and the tore part was then compressed by the tool, remaining on the machined surface. During type III chip formation, part of the workpiece above the path of the cutting edge was compressed by the tool, instead of being removed as a chip, so the compression occurred in wide area. The relationship between the formation of the machining defects such as torn grain or the compressed cells and the way chip is separated, deformed, or removed was clarified in this study
A New Assay Method of Retinal Reductase Activity in Rat Intestinal Mucosa and Its Enzymatic Properties
ラット小腸粘膜のレチナール還元酵素(RRase)のin vitroにおける活性測定法を確立すると共に,その系におけるレチナールの還元及び酸化反応について調べた.小腸のRRaseは摂取されたβ-カロテンなどプロビタミンAから生じるレチナールをレチノールに変える作用が主たる役割と考えられる酵素である.小腸粘膜ホモジェネートを用いてin vitroでRRase活性を測定すると,比活性の再現性が乏しく,またホモジェネート中でのRRaseの速やかな失活が起こる.これを防ぐためには,酵素調製用緩衝液にニコチンアミドやNADHなどのニコチンアミド誘導体を2mM以上加えるのが有効であることを見いだした.最適pHは4.3,cofactorとしてGSHを要求する点はすでにGoodmanらが報告している通りであるが,GSH以外のチオール試薬もGSHと同様に有効であった.EDTA添加によって活性を殆ど失うが,Ca2+,Mg2+の添加で活性が回復することから,これらが金属イオンとして要求されていると思われる.RRaseのkm値は83.3μMであり,200μM以上のレチナールを用いて活性測定を行うと120minで基質レチナールの40%以上が還元される.このことは,レチナール還元反応がレチノール生成に大きく傾いた反応であることを示すものである
Cholesteric liquid crystal laser in a dielectric mirror cavity upon band-edge excitation
Low threshold laser action of dye-doped cholesteric liquid crystals ( CLCs) is demonstrated using an input circularly polarized light whose handedness is the same as the cholesteric helix of the sample at the high-energy band edge of the reflection band. The mechanism originates from the dramatic increase of the photon density of state at the band edges. We also demonstrate an enhanced laser action of a CLC in a dielectric multilayer cavity. In such a device configuration, the band-edge excitation at high-energy band edge improves the lasing performance not only for the same handedness circularly polarized pump beam as the cholesteric helix but also for the opposite one. It stems from the polarization independence of the dielectric multilayers
Lactams. XX. Decarboxylation of Unsaturated Acids incorporated into Six-Membered Lactam Systems
The thermal decarboxylation of some unsaturated acids (1,5,6,8,and 9) incorporated into six-membered lactams was examined. Although 8 and 9 did not undergo decarboxylation when heated neat at 175-180℃ and 240-245℃, respectively, for 2 h, 1,5,and 6 were decarboxylated in 1,1,2,2-tetrachloroethane at 135℃. The relative ease of the reaction was in the order of 1≥6≫5. In the case of 1,the rate-decreasing effects observed on dilution and on the addition of trichloroacetic acid suggest the reaction to be a dimeric intermolecular process
Low-threshold and high efficiency lasing upon band-edge excitation in a cholesteric liquid crystal
A low threshold and high efficiency laser based on dye-doped cholesteric liquid crystals (CLCs) is demonstrated using an input excitation with the same handedness of circular polarization as the helical structure of the sample at the shorter wavelength band edge of the reflection band. The responsible mechanism originates from the dramatic increase of the optical density of state (DOS) at the band edges. The calculated DOS of the CLC system confirms the authors\u27 experimental results
Major Causes of Death among Older Adults after the Great East Japan Earthquake : A Retrospective Study
This retrospective study investigated the 3-year impact of the Great East Japan Earthquake (GEJE) of 2011 on deaths due to neoplasm, heart disease, stroke, pneumonia, and senility among older adults in the primarily affected prefectures compared with other prefectures, previous investigations having been more limited as regards mortality causes and geographic areas. Using death certificates issued between 2006 and 2015 (n = 7,383,253), mortality rates (MRs) and risk ratios (RRs) were calculated using a linear mixed model with the log-transformed MR as the response variable. The model included interactions between the area category and each year of death from 2010 to 2013. The RRs in the interaction significantly increased to 1.13, 1.17, and 1.28 for deaths due to stroke, pneumonia, and senility, respectively, in Miyagi Prefecture in 2011, but did not significantly increase for any of the other areas affected by the GEJE. Moreover, increased RRs were not reported for any of the other years. The risk of death increased in 2011; however, this was only significant for single-year impact. In 2013, decreased RRs of pneumonia in the Miyagi and Iwate prefectures and of senility in Fukushima Prefecture were observed. Overall, we did not find evidence of strong associations between the GEJE and mortality
<Abstract of published report>Two New β-Hydroxychalcones from the Root Bark of Pongamia pinnata.
Oseltamivir Prescription and Regulatory Actions Vis-à-Vis Abnormal Behavior Risk in Japan: Drug Utilization Study Using a Nationwide Pharmacy Database
BACKGROUND: In March 2007, a regulatory advisory was issued in Japan to restrict oseltamivir use in children aged 10-19 years because of safety concerns over abnormal behavior. The effectiveness and validity of regulatory risk minimization actions remain to be reviewed, despite their significant public health implications. To assess the impact of the regulatory actions on prescribing practices and safety reporting. METHODOLOY/PRINICPAL FINDINGS: In this retrospective review of a nationwide pharmacy database, we analyzed 100,344 dispensation records for oseltamivir and zanamivir for the period from November 2006 to March 2009. The time trend in dispensations for these antiviral agents was presented before and after the regulatory actions, contrasted with intensity of media coverage and the numbers of spontaneous adverse reaction reports with regard to antivirals. The 2007 regulatory actions, together with its intense media coverage, reduced oseltamivir dispensation in targeted patients in fiscal year 2008 to 20.4% of that in fiscal year 2006, although influenza activities were comparable between these fiscal years. In contrast, zanamivir dispensation increased approximately nine-fold across all age groups. The number of abnormal behavior reports associated with oseltamivir in children aged 10-19 years decreased from fiscal year 2006 to 2008 (24 to 9 cases); this decline was offset by the increased number of reports of abnormal behavior in children under age 10 (12 to 28 cases). The number of reports associated with zanamivir increased in proportion to increased dispensation of this drug (11 to 114 cases). CONCLUSIONS/SIGNIFICANCE: The 2007 actions effectively reduced oseltamivir prescriptions and the number of reports of abnormal behavior in the targeted group. The observed increase in abnormal behavior reports in oseltamivir patients under age 10 and in zanamivir patients suggests that these patient groups may also be at risk, calling into question the validity of the current discrimination by age and agent (Abstract translation is available in Japanese: Appendix S1)
Purines. LXV. Preparatory study for the syntheses of the marine sponge purines agelasimines-A and -B: Synthesis and acetylation of their N(7)-benzyl analogues
Four-step synthetic routes from 3-methyladenine (10) to 7-benzyl-N6,3-dimethyladenine (1b) and 7-benzyl-1,2-dihydro-1,3-dimethyladenine (2b), selected as models for the marine sponge alkaloids agelasimine-A (1a) and agelasimine-B (2a), respectively, have been established. The key steps involved are regioselective methylations of 7-benzyl-3-methyladenine (8) and 7-benzyl-1,2-dihydro-3-methyladenine (11). The reaction of 1b with acetic anhydride in pyridine was found to give the monocyclic imidazole derivative 29b. A similar acetylation of 2b yielded the N6-acetyl derivative 20b. When treated with boiling H2O, 20b afforded 7-benzyl-2,3-dimethylhypoxanthine (21b) and a compound inferred to be the dihydrohypoxanthine derivative 30. Probable pathways to 29b from 1b and to 21b and 30 from 20b are proposed
HIV-1 nef suppression by virally encoded microRNA
BACKGROUND: MicroRNAs (miRNAs) are 21~25-nucleotides (nt) long and interact with mRNAs to trigger either translational repression or RNA cleavage through RNA interference (RNAi), depending on the degree of complementarity with the target mRNAs. Our recent study has shown that HIV-1 nef dsRNA from AIDS patients who are long-term non-progressors (LTNPs) inhibited the transcription of HIV-1. RESULTS: Here, we show the possibility that nef-derived miRNAs are produced in HIV-1 persistently infected cells. Furthermore, nef short hairpin RNA (shRNA) that corresponded to a predicted nef miRNA (~25 nt, miR-N367) can block HIV-1 Nef expression in vitro and the suppression by shRNA/miR-N367 would be related with low viremia in an LTNP (15-2-2). In the 15-2-2 model mice, the weight loss, which may be rendered by nef was also inhibited by shRNA/miR-N367 corresponding to suppression of nef expression in vivo. CONCLUSIONS: These data suggest that nef/U3 miRNAs produced in HIV-1-infected cells may suppress both Nef function and HIV-1 virulence through the RNAi pathway
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