A novel method for the terpene synthesis by the ring-opening reaction of β-methyl-β-propiolactone

A new route for the terpene synthesis is investigated, which undergoes via terpene carboxylic acids as key intermediates obtained by the regiospecific ring opening of β-methyl-β-propiolactone with a cuprate or with a Grignard reagent in the presence of a copper catalyst.     

High oxygen-reduction activity of silk-derived activated carbon

Activated carbon prepared from silk fibroin, which is free of metal elements, showed a high catalytic activity for the oxygen-reduction reaction (ORR). The activated carbon had a very high onset potential of E_onset = 0.83 V (vs. RHE) in oxygen-saturated 0.5 M H₂SO₄ at 60 °C. The ORR on the activated carbon proceeded by a four-electron process in the high-electrode-potential region; this gradually decreased to a 3.5-electron reaction below about 0.6 V (vs. RHE). Only about 1% of nitrogen atoms (mostly quaternary) remained in the activated carbon by heat-treatment at up to 1200 °C are responsible for the high catalytic activity. The open circuit voltage of a polymer electrolyte fuel cell using the activated carbon as the cathode and a platinum/carbon black anode under pure oxygen and hydrogen gases, respectively, both at one atmosphere, was 0.96 V at 27 °C.     

Growth of zincblende MgS/ZnSe superlattices and their heterointerface properties

MgS naturally forms the rocksalt structure, but zincblende MgS/ZnSe superlattices were grown with atmospheric-pressure MOVPE. The lattice constant of zincblende MgS was determined to be 5.59 Å from a series of X-ray measurements. The purging effect during the growth of MgS/ZnSe heterointerfaces was studied. While purging with a Se precursor resulted in the formation of an extra MgSe-related interface layer, purging with a Zn precursor improved the abruptness of the heterointerfaces.     

Simulation of dynamic response to an electric field of surface stabilized antiferroelectric liquid crystals

Responses of surface stabilized antiferroelectric liquid crystals (SSAFLCs) to an electric field are simulated based on a model of the AFLC phase. The apparent tilt angle, the polarization reversal current and the optical transmission under applied triangular wave voltages are calculated. The results obtained systematically explain the experimental observations fairly well. The effects of parameters such as amplitude and frequency of applied voltages, an antiferroelectric coupling parameter and surface anchoring strength on these phenomena are discussed.     

Analysis of the expression of two phosphoglycerate kinase genes in a mouse cultured cell line during activation and inactivation of the c-myc gene

The effect of a change in the concentration of c-myc protein on the expression of genes for two phosphoglycerate kinase isozymes was investigated. The steady state levels of messenger ribonucleic acids (mRNAs) for sperm-type and non-sperm-type proteins were determined by blot hybridization using the RNA of the mouse cell line 38-2 containing the inducible rat c-myc gene cultured under various conditions. Without induction the c-myc gene. mRNA for non-sperm-type protein was detected at a level that remained essentially constant during both activation and inactivation of the c-myc gene. mRNA for sperm-type protein was not detected in 38-2 cells cultured under any conditions used. Change in the amount of c-myc protein alone does not appear to bring about a switch of the expression of the two phosphoglycerate kinase genes during spermatogenesis in mouse testis.     

Magnetism and Superconductivity inCeCu2(Si1−xGex)2 Probed by Cu NQR

We report Cu-NQR results on Ge-doped heavy-fermion superconductor CeCu₂(Si_1–x Ge _x )₂ (0<x0.2) and undoped Ce_0.99Cu_2.02Si₂. The main effect of the Ge doping is considered to be a negative pressure, since the strength of hybridization decreases by the Ge doping. With increasing x, the dynamical characteristics of the magnetic order at x=0 change to more static ones which suggests a localized regime above x0.25. From the derived T–x phase diagram, it is suggested that the magnetic and the superconducting phases are almost degenerate in undoped CeCu₂Si₂. An exotic interplay between the magnetism characterized by the slow fluctuations and the superconductivity is implied in the region of small x.