In situ X-ray diffraction experiments of Mg0.9Al0.2Si0.9O3 perovskite were carried out using a diamond anvil cell combined with synchrotron radiation and an imaging plate X-ray detector under hydrostatic pressures up to 9GPa at room temperature. The observed unit cell volumes were fitted to the third-order Birch-Murnaghan equation of state, yielding a bulk modulus KT0=225.5±1.2GPa when its pressure derivative KT0'=4 is assumed. This KT0 value is about 10-13% lower than that of MgSiO3 perovskite reported so far.
The incorporation rates of growth units into kink sites on growth surfaces of crystals by series processes via intermediate sites from solution are investigated by changing the energy states of the intermediate sites and the activation energies for the processes. A simple model where the activation energies are proportional to the differences of the energy states between sites is taken in the present study to illustrate the concept. The model shows that the incorporation rate of a series process via an intermediate site in a certain energy state becomes much larger than those via intermediate sites in different energy states, suggesting the existence of a rapid-incorporation path in surface kinetics of crystal growth.
An advanced robust optimization (RO) model to manage water quality in river systems is proposed which embraces every conceivable uncertainty present in water quality problems and is applicable to a network of streams, as an improvement over our earlier RO model. Biochemical oxygen demand (BOD) and dissolved oxygen (DO) concentrations of the incoming water from the upstream ends are added in a family of basic uncertainty parameters. In order to widen a spectrum of feasible solutions, the number of constraints associated with in-stream water quality standards is reduced. An optimization problem of BOD loading to a river system is solved with consideration to the solution robustness related to variability of the BOD load and to the model robustness related to violations of the in-stream water quality standards prescribed. Through an optimization example, it is demonstrated that the model proposed successfully provides a series of alternative strategies for water quality management in a multitudinously delimited network of streams.
Chara myosin is a plant myosin involved in cytoplasmic streaming of Characean cells and the fastest of all myosins observed so far with in vitro motility assay. Movement of F-actin on Chara myosin was completely inhibited by muscle tropomyosin. In concert with this, the actin activated Chara myosin ATPase was also completely inhibited by tropomyosin. The movement of the thin filament of F-actin with native tropomyosin, the complex of tropomyosin and troponin, was inhibited on Chara myosin and the actin activated ATPase of Chara myosin was also inhibited by native tropomyosin. With careful observations, Chara myosin occasionally moved actin filaments in the presence of native tropomyosin and Ca2+. This indicates that the effect of tropomyosin of the thin filament in the“ON”state is not exactly the same as that of tropomyosin alone on F-actin.
One important theme in organic synthesis is to accomplish highly selective transformations under mild conditions, which yield only desirable products. During the past two decades, we have developed several useful tools to achieve this, i.e., organochromium reagents. This review focuses on the following themes: 1) The historical background of organochromium reagents. 2) The development of the allylic chromium reagent (Nozaki-Hiyama reaction). 3) Nickel-catalyzed addition of alkenyl-, aryl-, and alkynyl halides to aldehydes (Nozaki-Hiyama-Kishi (NHK) reaction). 4) Wittig-type olefination with geminal dichromium reagents. 5) Representative applications of organochromium reagents to the total syntheses of biologically active compounds.