A novel photoreactive amphiphile of nitrophenylazide for immobilization of bioactive proteins

Monolayers of an amphiphilic nitrophenylazide (ANPA) derivative were prepared and their ability to immobilize a protein molecule by a photochemical binding reaction was demonstrated as a novel means to constitute a biofunctional membrane. Molecular orientations and photoreactions in the ANPA monolayers were investigated by Fourier transform IR spectroscopy. Rapid photolysis of ANPA was observed which reflects decomposition of the azide group to a reactive nitrene radical intermediate. As an enzyme, glucose oxidase (GOD) was immobilized on a monomolecular film of ANPA, coated on a substrate, by means of enzyme adsorption at the solid-solution interface and subsequent photolysis of ANPA. Radioisotope labelling experiments revealed that the enzyme was immobilized at a high surface concentration which corresponds to a closely packed monolayer of GOD. The specific activity of the immobilized enzyme was estimated to be high compared with those of other systems involving the adsorption of this enzyme. The usefulness of the present technique for fabricating biofunctional monolayer assemblies is discussed.     

Determination of bisphenol A in canned vegetables and fruit by high performance liquid chromatography

A high performance liquid chromatograph y (HPLC) method was developed for the determination of bisphenol A (BPA) that had migrated into canned fruit and vegetables. BPA was extracted with acetonitrile from the solid portion of canned food, and with an OASIS HLB cartridge from the aqueous portion, respectively. Both extracts were cleaned up on a Florisil cartridge. The HPLC separation was carried out on a Wakosil II 3C18 RS column (4.6 × 150mm) with acetonitrile-water (40:60, v/v) as a mobile phase with a flow rate of 0.8 ml/min. BPA was detectable by UV detector at 228 nm and determined with the similarity of chromatographic peak spectrum by multiwavelength detector (similarity index was 0.99 or above). The quantification limits were 10 ng/g for the solid portion and 5 ng/ml for the aqueous portion, respectively. BPA was mainly detected in the solid portion of canned food and found at the maximum level of 11 μg per can. To verify migration into the solid portion of canned food, a partitioning experiment was carried out.     

Effects of winding connections on characteristics of a five‐phase stepping motor

A method for calculating the single‐step response of five‐phase hybrid stepping motors is obtained. The effects of winding connecting methods—(1) star‐bipolar SB, (2) pentagon PD, and (3) new pentagon NP—on the single‐step response are investigated. By application of the above calculation method, the continuous rotating characteristics are studied. It is found that the maximum slewing pulse rate of NP is higher than that of SB and PD connections, and that the variation of the rotor speed at high speed with the SB and PD connections is larger than that with the NP connection. The effects of the current waveform on the oscillation characteristics and relations between the current waveform and the winding connections are investigated. © 2001 Scripta Technica, Electr Eng Jpn, 136(1): 47–56, 2001     

Study on environmental effect on fatigue and creep-fatigue strength of 316FR stainless steel in sodium at elevated temperature

Low-carbon 316 stainless steel with medium-nitrogen (316FR) is considered as the principal structural material for next generation fast breeder reactor (FBR) plants in Japan. The material strength standard and the creep-fatigue life evaluation method for 316FR have been developed. However, they are based on the results of material tests in air, while actual structural material will be used mainly in liquid sodium environment in the plants. In order to clarify the environmental effect, cyclic bending tests were carried out with and without hold time in sodium. Tested materials were 316FR and conventional 304 and 316 stainless steels. Weld metal of 316FR was also tested. As a result, it was found that fatigue and creep-fatigue lives of 316FR in sodium were larger than those in air and no explicit consideration of the environmental effect is necessary in design. It was also found that the life evaluation method based on the ductility exhaustion concept is applicable to creep-fatigue life assessment in sodium.     

40 Gbit/s return-to-zero transmission over 500 km of standard fibreusing chirped fibre Bragg gratings with small group delay ripples

A 40 Gbit/s return-to-zero transmission has been successfully achieved over 500 km using standard fibres (non-dispersion shifted fibre, singlemode fibre) and chirped fibre Bragg gratings (CFBG). CFBGs were fabricated with small group delay ripples, and error free transmission (BER <1×10^-12) was achieved using these CFBGs for dispersion compensation     

A 250-Mb/s/pin, 1-Gb double-data-rate SDRAM with a bidirectionaldelay and an interbank shared redundancy scheme

This paper describes three circuit technologies indispensable for high-bandwidth multibank DRAM's. (1) A clock generator based on a bidirectional delay (BDD) eliminates the output skew. The BDD measures the cycle time as the quantity charged or discharged of an analog quantity, and replicates it in the next cycle. This achieves a 0.18-mm ², two-cycle-lock clock generator operating from 25 to 167 MHz with a 30-ps resolution. (2) A quad-coupled receiver eliminates the internal skew caused by the difference between a rise input and a fall input by 40%. (3) An interbank shared redundancy scheme (ISR) with a variable unit redundancy (VUR) efficiently increases yield in multibank DRAM's. The ISR allows redundancy match circuits to be shared with two or more banks. The VUR allows the number of units replaced to be variable. These circuit technologies achieved a 250-Mb/s/pin, 8-bank, 1-Gb double-data-rate synchronous DRAM     

Optical Fiber Cable Measurements in the Field

The optical fiber cable measurement instruments developed by NTF for field use in the 1.3 μm wavelength are discussed. The properties of a stabilized optical light source for single-mode fiber attenuation measurement, optical time-domain reflectometer using a Q-switched Nd:YAG laser as a light source, and chromatic dispersion measurement instrument are described. From the measurement results, these instruments are revealed to be suitable in constructing and maintaining singlemode fiber optical transmission lines.