Polarisation characteristics of a side-tunnel fibre

Modal birefringence and polarisation mode dispersion in a single-mode fibre having vacuum pits beside the core are measured in the wavelength region from 0.633 ?m to 1.52?m. Both quantities monotonically increase as the operation wavelength becomes large. The magnitudes of birefringence and modal dispersion are evaluated to be 1.0 × 10?4 at 1.52?m and 148 ps/km at 1.41 ?m, respectively. These values are much less than those predicted theoretically for side-tunnel-type optical fibres.     

The leaching of chalcopyrite with ferric chloride

A comparative study of electrochemical leaching and chemical leaching of chalcopyrite was done to elucidate the leaching mechanism of chalcopyrite with FeCl₃. The leaching rate of chalcopyrite exhibits a half order dependency on the FeCl₃ concentration, whereas it is independent of the FeCl₂ concentration. The mixed potential of chalcopyrite exhibits a 72 mV · decade⁻¹ dependency upon FeCl₃ concentration; no influence on the mixed potential was observed by the addition of FeCl₂. In FeCl₃ solutions acidified with HC1, the predominant chemical species of Fe(III) was found to be FeCl ₂ ^u+ from equilibrium calculations. The concentration of this species is approximately proportional to the amount of FeCl₃ added to the solutions. Based on these observations, an electrochemical mechanism is proposed which involves the oxidation of chalcopyrite and the reduction of FeCl ₂ ⁺ , the predominant species of Fe(III). By converting the leaching rate to electric current density,i, 140 mV · decade⁻¹ dependency of mixed potential,E, against logi is obtained. This dependency of the chemical leaching of chalcopyrite with FeCl₃ as well as its activation energy agree with those for electrochemical leaching. These findings strongly support the electrochemical mechanism of FeCl₃ leaching of chalcopyrite. Formerly Graduate Student, Kyoto University     

Metal cation–acidic proton bifunctional catalyst for methane activation: conversion of CH4 in the presence of ethylene over metal cations-loaded H-ZSM-5

It has been investigated that ¹³CH₄ reacts with ethylene over metal cations such as indium cations-loaded H-ZSM-5 to form singly ¹³C-labeled propylene (¹³C¹²C₂H₆) and hydrogen at 673 K. The heterolytic dissociation of C---H bond in methane presumably proceeds by the reaction of methane with metal cations for the formation of CH₃^δ+ and metal hydride species, thus allowing the reaction of CH₃^δ+ with ethylene to form propylene and acidic protons. Metal cations are regenerated by the reaction of silver-hydride species with acidic protons, and hydrogen is simultaneously formed. Thus, bifunctionality of metal cations and acidic protons is essential for the activation of methane.     

R1128 substances, novel non-steroidal estrogen-receptor antagonists produced by a Streptomyces. III. Pharmacological properties and antitumor activities

R1128 B (1,3,6-trihydroxy-8-n-butylanthraquinone), a new antibiotic produced by Streptomyces sp. No. 1128, inhibited estrogen binding to its receptor. The IC50 value of R1128 B for partially purified rat uterine cytosol receptor was 1.2 x 10(-7) M. However, the IC50 value of R1128 B against androgen-receptor binding was about 50-fold greater than that against estrogen-receptor binding. R1128 B was a competitive inhibitor against estrogen-receptor binding. R1128 B inhibited the growth of estrogen-responsive human mammary adenocarcinoma MCF-7 cells in soft agar. This inhibition, however, was reversed when estradiol was added to the culture medium. R1128 B showed antitumor activities against MCF-7 both xenografted to nude mice and implanted in subrenal capsule of mice (SRC assay). The potency of R1128 B was about 8-fold lower than that of tamoxifen both in vitro and in vivo.     

Mechanical characteristics related to fault currents in bundle conductors

The flow of fault currents in bundled conductors induces an electromagnetic attraction between subconductors and thereby the bus conductor system to an extremely high level of tension. This tension, which is the most important factor in designing the mechanical strength of the system, is determined by a large number of parameters—the magnitude of the fault current, the size and number of the subconductors, spacer interval, the spring of the structure, and so on. Full-scale 63-kA class fault current tests were carried out on eight types of bus conductors used in 275-and 500-kV subconductors, and measurements of fluctuation in tension were used to clarify the relationship between the various parameters and maximum tension at fault time. A method also was devised for calculating maximum tension at fault time on the basis of the various parameters, and it has been applied in the mechanical strength design of the bus conductor system.     

High surface area solids obtained by intercalation of iron oxide pillars in montmorillonite

When montmorillonite is dispersed in aqueous solutions of trinuclear acetato-hydroxo iron(III) nitrate, [Fe₃(OCOCH₃)₇OH]NO₃, the interlayer cations of the montmorillonite are exchanged with the partially hydrolyzed trinuclear acetato complex ions. On heating the exchanged complex ions are converted into iron oxide pillars which keep the silicate layers apart and form micropores between the layers. The resulting product has a basal spacing of 16.7 Å and a specific surface area of about 300 m²/g at 500°C. Adsorption isotherms for various vapors on the product have been measured.     

A 20-ns 256 K×4 FIFO memory

A 256 K×4 FIFO (first-in-first-out) CMOS memory with 20-ns access time and 30-ns cycle time is described. To accomplish full static and asynchronous operation, signal synchronizer and arbiter circuits have been developed and implemented into the device. A pair of 120-word×4-bit static memories are furnished to provide 20-ns data access from the very first read cycle. The average current measured at 30-ns read/write operation and the standby current are typically 23 and 1.2 mA, respectively     

Bronchial asthma due to Stronger Neo-Minophagen C

A 24-year-old woman who visited our hospital because of urticaria had a bronchial asthma attack about 5 min. after receiving Stronger Neo-Minophagen C (SNMC) intravenously. A skin test for SNMC and its components (glycyrrhizin, L-cystein, aminoacetic acid, and sodium sulfite) was positive for SNMC and borderline for sodium sulfite after 15 min. A skin test for mixtures of L-cystein and sodium sulfite was also positive. Inhalation provocation tests for SNMC and mixtures of L-cystein and sodium sulfite were positive after 5 min. An inhalation provocation test for sulpyrin was also positive. The patient's bronchial asthma attack was ascribed to SNMC. Type I allergy to mixtures of L-cystein and sodium sulfite was the suspected cause.     

Exchange of aspartate and alanine. Mechanism for development of a proton-motive force in bacteria

We examined the idea that aspartate metabolism by Lactobacillus subsp. M3 is organized as a proton-motive metabolic cycle by using reconstitution to monitor the activity of the carrier, termed AspT, expected to carry out the electrogenic exchange of precursor (aspartate) and product (alanine). Membranes of Lactobacillus subsp. M3 were extracted with 1.25% octyl glucoside in the presence of 0. 4% Escherichia coli phospholipid and 20% glycerol. The extracts were then used to prepare proteoliposomes loaded with either aspartate or alanine. Aspartate-loaded proteoliposomes accumulated external [3H]aspartate by exchange with internal substrate; this homologous self-exchange (Kt = 0.4 mm) was insensitive to potassium or proton ionophores and was unaffected by the presence or absence of Na+, K+, or Mg2+. Alanine-loaded proteoliposomes also took up [3H]aspartate in a heterologous antiport reaction that was stimulated or inhibited by an inside-positive or inside-negative membrane potential, respectively. Several lines of evidence suggest that these homologous and heterologous exchange reactions were catalyzed by the same functional unit. Thus, [3H]aspartate taken up by AspT during self-exchange was released by a delayed addition of alanine. In addition, the spontaneous loss of AspT activity that occurs when a detergent extract is held at 37 degrees C prior to reconstitution was prevented by the presence of either aspartate (KD(aspartate) = 0.3 mm) or alanine (KD(alanine) > or = 10 mm), indicating that both substrates interact directly with AspT. These findings are consistent with operation of a proton-motive metabolic cycle during aspartate metabolism by Lactobacillus subsp. M3.