Cytotoxic and apoptosis-inducing ent-kaurane-type diterpenoids from the Japanese liverwort Jungermannia truncata NEES

Five new ent-kaurane-type diterpenoids and a new gymnomitrane (=barbatane)-type sesquiterpenoid have been isolated from the Japanese liverwort Jungermannia truncata NEES, together with twelve previously known ent-kaurane-type diterpenoids. The structures of the new compounds were elucidated by two-dimensional (2D) NMR experiments and chemical reaction. Some of the isolated compounds showed cytotoxicity against human leukemia cell lines and induced apoptosis.     

An enzyme immunosensor for the electrochemical determination of the tumor antigen α-fetoprotein

A specific sensor for a tumor antigen, α-fetoprotein (AFP) can be prepared from a membrane with immobilized antibody and an oxygen probe with a permeable teflon membrane. Anti-AFP antibody is covalently immobilized on a membrane prepared from cellulose triacetate, 1,8-diamino-4-aminomethyloctane and glutaraldehyde. The sensor is applied to enzyme immunoassay based on competitive antigen-antibody reaction with catalase-labelled antigen. After competitive binding of free and catalase-labelled AFP, the sensor is examined for catalase activity by amperometric measurement after addition of hydrogen peroxide. AFP can be determined in the range 10^-11–10^-8 g ml^-1.     

Anomalous fluctuation and relaxation in unstable systems

The essential ideas of the scaling theory of transient phenomena proposed by the author for a single macrovariable near the instability point are extended to multi-macrovariables in nonequilibrium systems. The time region is divided into three regimes according to the scaling behavior of the fluctuating parts of the macrovariables. In the first regime, the fluctuation is Gaussian and it is described by the linearized stochastic equation (or linear Fokker-Planck equation). In the second regime, the fluctuation is non-Gaussian, but it is probabilistic or stochastic (not dynamical) in the sense that the stochastic nature comes from the probability distribution in the initial regime and that each representative motion is deterministic, namely a random force can be neglected asymptotically in the second regime. In the final regime, the fluctuation is again Gaussian. A fluctuation-enhancement theorem for multi-macrovariables is given, which states that the fluctuation becomes enhanced by the order of the system size in the second regime, which is of order log , if the initial system is located just at the unstable point. An anomalous fluctuation theorem for multi-macrovariables is also proven, which states that the fluctuation is anomalously enhanced in proportion to ^–2 at times of order log if the initial system deviates by from the unstable point.This work is partially financed by the Scientific Research Fund of the Ministry of Education.     

Nonlinear fluctuations,separation of procedures,and linearization of processes

A concept of separation of procedures is introduced to study cooperative phenomena theoretically. Some typical important examples of this concept are presented to clarify its usefulness; Kubo's stochastic Liouville equation, some generalized diffusionlike equations, van Kampen's expansion, Kubo's extensivity, Prigogine's entropy production, the scaling theory of transient phenomena based on the Lie algebra, and Suzuki's CAM theory of cooperative phenomena are discussed from the new viewpoint of separation of procedures.This paper is dedicated to Ilya Prigogine on the occasion of his 70th birthday.     

Intramolecular Ynamide–Benzyne (3+2) Cycloadditions

We report herein intramolecular (3+2) cycloaddition reactions between ynamides as three-atom components and benzyne. In these intramolecular reactions, the two-bond formation is realized by exploiting benzyne precursors that contain a chlorosilyl group as a linking functionality. This method thus highlights the ambivalent character of the intermediate indolium ylide, which exhibits both nucleophilic and electrophilic properties at its C2 atom.     

Solvent-controlled leaving-group selectivity in aromatic nucleophilic substitution

A solvent-controlled inversion of leaving group ability allows selective access to either of two internal substitution products in S(N)Ar reactions of substrates with competing leaving groups. Application of this principle in a selective synthesis of the highly functionalized xanthone core of the antibiotic FD-594 is presented.     

Convergence of mean-field approximations in site percolation and application of CAM tod=1 further-neighbors percolation problem

We study the mean-field approximation in the site-percolation problem. Using the analog of the Simon-Lieb inequality, we show that the mean-field critical probability is convergent to the exact value when the size of clusters tends to infinity. Applying this approximation to the one-dimensional further-neighbor percolation problem and calculating some critical coefficients, we prove that the asymptotic scaling relations predicted by the coherent-anomaly method are satisfied.     

(+)‐(14β)‐14‐Ethylmatridin‐15‐one,a New Quinolizidine Alkaloid from the Poisonous Plant Oxytropis ochrocephala Bunge

A new matrine alkaloid derivative (+)‐(14β)‐14‐ethylmatridin‐15‐one ( 1 ) was isolated from the poisonous plant Oxytropis ochrocephala Bunge . The structure was established by spectroscopic methods, including extensive 1D‐ and 2D‐NMR experiments.     

Crystal Structures of Two-Dimensional Coordination Polymer Fe(Methylpyridine)2Ni(CN)4

Abstract

Two-dimensional coordination polymer compounds FeL₂Ni(CN)₄ (L: 2, 3, or 4-methylpyridine) have been synthesized and characterized by single crystal X-ray diffraction method.     

Heat transfer and fluid dynamics of air–water two-phase flow in micro-channels

Heat transfer, pressure drop, and void fraction were simultaneously measured for upward heated air–water non-boiling two-phase flow in 0.51 mm ID tube to investigate thermo–hydro dynamic characteristics of two-phase flow in micro-channels. At low liquid superficial velocity j_l frictional pressure drop agreed with Mishima–Hibiki’s correlation, whereas agreed with Chisholm–Laird’s correlation at relatively high j_l. Void fraction was lower than the homogeneous model and conventional empirical correlations. To interpret the decrease of void fraction with decrease of tube diameter, a relation among the void fraction, pressure gradient and tube diameter was derived. Heat transfer coefficient fairly agreed with the data for 1.03 and 2.01 mm ID tubes when j_l was relatively high. But it became lower than that for larger diameter tubes when j_l was low. Analogy between heat transfer and frictional pressure drop was proved to hold roughly for the two-phase flow in micro-channel. But satisfactory relation was not obtained under the condition of low liquid superficial velocity.