299 research outputs found

    Radiation Safety

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    On the Friction Coefficient for Turbulent Flow ThroughSectionally Roughened Square Ducts

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    The friction coefficient of sectionally rough pipes has not been studied yet. The friction coefficient for turbulent flow through sectionally roughened square ducts is experimentally studied. Four arrangements of rough surfaces are used to obtain the sectionally roughened square ducts. It is attempted to predict the friction coefficient for sectionally roughened square ducts from the friction coefficients for alloverly roughened and smooth square ducts

    Spin-dependent observables in surrogate reactions

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    Observables emitted from various spin states in compound U nuclei are investigated to validate usefulness of the surrogate reaction method. It was found that energy spectrum of cascading γ\gamma-rays and their multiplicities, spectrum of evaporated neutrons, and mass-distribution of fission fragments show clear dependence on the spin of decaying nuclei. The present results indicate that they can be used to infer populated spin distributions which significantly affect the decay branching ratio of the compound system produced by the surrogate reactions

    An Optimal Design Method for CMOS Even-Stage Ring Oscillators Containing Latches

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    This paper describes a design method for complementary metal oxide semiconductor (CMOS) ring oscillators composed of even-stage inverters. First, we propose a quantitative method to evaluate oscillation stability for an even-stage ring oscillator with a CMOS latch. The method uses static noise margin analysis to evaluate the static random access memory (SRAM) cell\u27s data storage stability, by observing the similarity between the oscillator and SRAM cell circuitry. Next, the method is extended to oscillators with multiple latches. Finally, by analyzing oscillation stability using this method, we find that the range of stable oscillation conditions can be drastically widened by adding multiple single-channel latch circuits, and also by an appropriate design of their polarities and insertion positions. We also clarify through Monte Carlo simulations, that the optimized oscillator circuit is robust under process, voltage and temperature fluctuations and device characteristic variations

    Matrix metalloproteinase-1 up-regulation by hepatocyte growth factor in human dermal fibroblasts via ERK signaling pathway involves Ets1 and Fli1

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    In this study, we clarified the molecular mechanism(s) underlying the regulation of matrix metalloproteinase (MMP)-1 gene by hepatocyte growth factor (HGF) in cultured human dermal fibroblasts. HGF induced MMP-1 protein as well as mRNA at a transcriptional level via extracellular signal-regulated kinase (ERK) signaling pathway. The region in the MMP-1 promoter mediating the inducible responsiveness to HGF, defined by the transient transfection analysis of the serial 5′ deletion constructs, contained an Ets binding site. Mutation of this Ets binding site abrogated the HGF-inducible promoter activity. Ets1 up-regulated the expression of MMP-1 promoter activity, whereas Fli1 had antagonistic effects on them. After HGF treatment, the protein level and the binding activity of Ets1 was increased and those of Fli1 was decreased, which were canceled by PD98059. These results suggest that HGF up-regulates MMP-1 expression via ERK signaling pathway through the balance of Ets1 and Fli1, which may be a novel mechanism of regulating MMP-1 gene expression
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