Chemical Stability of Binary Coulomb Compounds

Chemical stability of binary Coulomb compounds is studied through extensive calculation of their Madelung energies. A remarkable finding is that the compounds with disordered ionic arrangements in a certain range of the composition are stable against chemical separation beyond the charge ratio around 6; clearly the entropic effect due to finite temperature promotes the mixing of ions of different species. For the ordered AB₃‐type compounds, there exists a crystalline structure which is more chemically bounded than that of Dyson (1971). Relative stability o the ordered and disordered compounds is also discussed.     

Remarks on the energy decay for nonlinear wave equations with nonlinear localized dissipative terms

We derive an energy decay estimate for solutions to the initial-boundary value problem of a semilinear wave equation with a nonlinear localized dissipation. To overcome a difficulty related to derivative-loss mechanism we employ a ‘loan’ method.     

New Pseudostationary Phases for Electrokinetic Chromatography: A High-Molecular Surfactant and Proteins

To extend the applicability of electrokinetic chromatography (EKC), two new types of pseudostationary phases have been introduced. A high-molecular surfactant, butyl acrylate/butyl methacrylate/methacrylic acid copolymer (BBMA) is employed as a micellar forming surfactant for miccllar electrokinetic chromatography (MEKC). The critical micelle concentration of BBMA is essentially zero, which means the micellar concentration is constant irrespective of temperature and buffer. Some characteristic features of BBMA as the pseudostationary phase for MEKC is investigated in comparison with conventional ionic surfactants. Ovomucoid and avidin, which are proteins isolated from egg white, have been found to be useful chiral selectors in affinity EKC. A few examples of the separation of enantiomers with these proteins are shown.     

Wave operators to a quadratic nonlinear Klein-Gordon equation in two space dimensions

We study asymptotics around the final states of solutions to the nonlinear Klein-Gordon equations with quadratic nonlinearities in two space dimensions , where . We prove that if the final states

     

Partial molar volumes and partial molar adiabatic compressibilities of ethylenediamine complexes in water

Densities and ultrasonic propagating velocities of aqueous solutions of ethylenediamine complexes [Co(en)₃]Cl₃, [Cr(en)₃]Cl₃, [Ni(en)₃]Cl₂, and [Cu(en)₂]Cl₂ (en=ethylenediamine), as well as the ligand ethylenediamine were measured at 25°C. The infinite dilution values of the partial molar volume V ₂ ⁰ and partial molar adiabatic compressibility K _s ⁰ were evaluated. The value of K _s ⁰ of the ligand ethylenediamine is nearly zero. The values of V ₂ ⁰ and K _s ⁰ are combined with other interaction parameters, such as the Stokes radii and the viscosity B-coefficients, and their dependece upon the charge number and the stereochemistry of the complex ions is discussed.     

Radiative B meson decays into kpigamma and kpipigamma final states

We report observations of radiative B meson decays into the K+pi(-)gamma and K+pi(-)pi(+)gamma final states. In the B0-->K+pi(-)gamma channel, we present evidence for decays via an intermediate tensor meson state with a branching fraction of B(B0-->K(*)(2)(1430)(0)gamma)=[1.3+/-0.5(stat)+/-0.1(syst)]x10(-5). We measure the branching fraction B(B+-->K+pi(-)pi(+)gamma)=[2.4+/-0.5(stat) +0.4-0.2(syst)]x10(-5), in which the B+-->K(*0)pi(+)gamma and B+-->K+rho(0)gamma channels dominate. The analysis is based on a data set of 29.4 fb(-1) recorded by the Belle experiment at the KEKB collider.     

An Optochemical Oxygen Scavenger Enabling Spatiotemporal Control of Hypoxia

We present an optochemical O₂ scavenging system that enables precise spatiotemporal control of the level of hypoxia in living cells simply by adjusting the light intensity in the illuminated region. The system employs rhodamine containing a selenium or tellurium atom as an optochemical oxygen scavenger that rapidly consumes O₂ by photochemical reaction with glutathione as a coreductant upon visible light irradiation (560–590 nm) and has a rapid response time, within a few minutes. The glutathione-consuming quantum yields of the system were calculated as about 5 %. The spatiotemporal O₂ consuming in cultured cells was visualized with a hypoxia-responsive fluorescence probe, MAR. Phosphorescence lifetime imaging was applied to confirmed that different light intensities could generate different levels of hypoxia. To illustrate the potential utility of this system for hypoxia research, we show that it can spatiotemporally control calcium ion (Ca²⁺) influx into HEK293T cells expressing the hypoxia-responsive Ca²⁺ channel TRPA1.