354 research outputs found

    Limit theorem of the max-plus walk (Mathematical structures of integrable systems, its deepening and expansion)

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    Mathematical structures of integrable systems, its deepening and expansion. September 9-11, 2019. edited by Takao Suzuki. The papers presented in this volume of RIMS Kôkyûroku Bessatsu are in final form and refereed.The max-plus algebra is a semiring on Rmax = R⋁{-∞} with addition ⊕ and multiplication ⊗ defined by ⊕ = max and ⊗ = +, respectively. It is known that eigenvalues of max-plus matrices are equivalent to the maximal average weight of the corresponding directed graph. In [9], authors introduced the max-plus walk which is a walk model on one dimensional lattice on Z over max-plus algebra, and discussed its properties such as the conserved quantities and the steady state. In this paper, we will discuss the limit measure of the max-plus walk

    Electronic state analysis of Li2RuO3 positive electrode for lithium ion secondary battery

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    An investigation was made on the electronic structure of 4d transition metal layered oxide material of Li2RuO3 using X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS). The intensity of O K pre-edge peak increased for Li ion extracted samples, suggesting increased ligand holes. The Ru 3d XPS spectrum suggested the variation of local structure around Ru ions by extraction of Li ions. We conclude that the delithiation from Li2RuO3 is charge-compensated by O anions, and that the creation of the ligand holes reorganizes electronic structures composed of highly hybridized Ru 4d and O 2p orbitals

    S-Nitrosated alpha-1-acid glycoprotein exhibits antibacterial activity against multidrug-resistant bacteria strains and synergistically enhances the effect of antibiotics

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    Alpha-1-acid glycoprotein (AGP) is a major acute-phase protein. Biosynthesis of AGP increases markedly during inflammation and infection, similar to nitric oxide (NO) biosynthesis. AGP variant A (AGP) contains a reduced cysteine (Cys149). Previously, we reported that S-nitrosated AGP (SNO-AGP) synthesized by reaction with a NO donor, possessed very strong broad-spectrum antimicrobial activity (IC50 = 10−9-10−6 M). In this study, using a cecal ligation and puncture animal model, we confirmed that AGP can be endogenously S-nitrosated during infection. Furthermore, we examined the antibacterial property of SNO-AGP against multidrug-resistant Klebsiella pneumoniae and Pseudomonas aeruginosa to investigate the involvement of SNO-AGP in the host defense system. Our results showed that SNO-AGP could inhibit multidrug efflux pump, AcrAB-TolC, a major contributor to bacterial multidrug resistance. In addition, SNO-AGP decreased biofilm formation and ATP level in bacteria, indicating that SNO-AGP can revert drug resistance. It was also noteworthy that SNO-AGP showed synergistic effects with the existing antibiotics (oxacillin, imipenem, norfloxacin, erythromycin, and tetracycline). In conclusion, SNO-AGP participated in the host defense system and has potential as a novel agent for single or combination antimicrobial therapy

    Evaluation of the Electronic and Local Structure of Mn in Proton-Conducting Oxide, Ca(Zr,Mn)O3-δ, To Elucidate a Direct Hydrogen-Dissolution Reaction

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    The protonation mechanism in Mn-doped CaZrO3 (CZM), which involves a direct hydrogen dissolution from the surrounding H2 gas, was investigated by thermogravimetry (TG) and X-ray absorption spectroscopy (XAS). The TG results implied the formation of oxygen vacancies in a H2 atmosphere. The Mn K-edge XAS spectra indicated a reduction of the Mn ions and local structure variations around the Mn ion, but the Zr K-edge spectra were independent of the surrounding atmosphere. The amount of oxygen vacancies was smaller with respect to the reduction of the Mn ions, suggesting direct dissolution of hydrogen. Unlike many typical perovskite-type proton conductors, protonation by direct dissolution of hydrogen and not hydration was the predominant reaction in Mn-doped CaZrO3. Our experimental results demonstrated that the hydration reaction was suppressed because the oxygen vacancy was stable in the distorted ZrO6 symmetry in the CaZrO3 crystal host, whereas protonation proceeded by the direct dissolution of hydrogen stabilizing near the Mn ions in the interstitial sites at the distorted MnO6 octahedron symmetry. The experimental results showed that the structural configurations around dopants play important roles in the stabilization of protons in perovskite-type CZM materials. We demonstrated a new group of proton conductors that can overcome issues with conventional proton conductors by utilizing the direct hydrogen dissolution reaction

    A SCINTIGRAPHIC STUDY OF MASS PERISTALSIS IN HUMAN COLON

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    Although many attempts have been made to study human colonic motility, the colonic transit is still poorly understood. Both spontaneous and neostigmine-induced peristalsis of the colon were studied with scintigraphy. A polythene tube was inserted into the cecum through a colonofiberscope. 37 MBq of ⁹⁹ᵐTc-DTPA and 75 ml of saline were instilled and dynamic scan was begun. Eight healthy volunteers were examined by the method above mentioned. The sampling time was set at fifteen seconds in six persons and three seconds in the rest. 0.5 mg of neostigmine was injected intravenously to stimulate the paristalsis when no peristalsis occurred within thirty minutes after the study was begun. Dynamic scanning was performed for sixty to ninety minutes. This scintigraphic study revealed that the spontaneous and induced peristalsis were almost identical on colonogram. ⁹⁹ᵐTc-DTPA solution was propelled from the cecum and ascending colon to the sigmoid colon or the rectum for about fifteen seconds during mass peristalsis. Colonogram (time-activity curve) enables us to analyze mass peristalsis easily and more objectively than colonoscintigram. The spontaneous and neostigmine-induced peristalsis seemed to be almost identical in all but one of eight subjects

    Direct observation of reversible oxygen anion redox reaction in Li-rich manganese oxide, Li2MnO3, studied by soft X-ray absorption spectroscopy

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    Li-rich layered oxides have attracted attention as promising positive electrode materials for next-generation lithium-ion secondary batteries because of their high energy storage capacity. The participation of the oxygen anion has been hypothesized to contribute to these oxides' high capacity. In the present study, we used O K-edge and Mn L-edge X-ray absorption spectroscopy (XAS) to study the reversible redox reactions that occur in single-phase Li-rich layered manganese oxide, Li2MnO3. We semiquantitatively analyzed the oxygen and manganese reactions by dividing the charge/discharge voltage region into two parts. The O K-edge XAS indicated that the electrons at the oxygen site reversibly contributed to the charge compensation throughout the charge/discharge processes at operating voltages between 2.0 and 4.8 V vs. Li+/Li0. The Mn L-edge XAS spectra indicated that the Mn redox reaction occurred only in the lower-voltage region. Thus, at higher potentials, the electrons, mainly at the oxygen site, contributed to the charge compensation. Peaks whose energies were similar to peroxide appeared in and then disappeared from the O K-edge spectra obtained during the reversible redox cycles. These results indicate that the reorganization of the oxygen network in the crystal structure affects the redox components. By using two kinds of detection modes with different probing depths in XAS measurements, it was found that these redox reactions are bulk phenomena in the electrode
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