Utilization of the same DNA replication origin by human cells of different derivation

In the past, a highly sensitive and efficient method was developed to map DNA replication origins in human cells, based on quantitative PCR performed on nascent DNA samples. This method allowed the identification of a replication origin in the myeloid HL-60 cell line, located on chromosome 19 within an approximately 500 bp segment near the lamin B2 gene [Giacca et al. (1994) Proc. Natl. Acad. Sci. USA, 91, 7119]. The same procedure has now been further simplified and extended to a variety of other exponentially growing human cells of different histological derivation (three neural, one connectival and one epithelial), with a nearly diploid chromosomal content. In all the six cell lines tested, the origin activity within the lamin B2 gene domain was localized to the same region. Furthermore, the lamin B2 origin was also found to be active in stimulated, but not in quiescent, peripheral blood lymphocytes.     

Significance of attached cyanobacteria relevant to the occurrence of musty odor in Lake Kasumigaura

The microorganisms and compounds causing musty odor in the second largest lake in Japan, Lake Kasumigaura, where the water is used for drinking, fisheries and agricultural purposes, were examined during the severe occurrence of musty odor in 1989 and 1990. This study was undertaken to determine the microorganisms and their metabolites responsible for the musty odor. Phormidium tenue, which has been reported to be the main contributor of the odor in Lake Kasumigaura, was isolated. Furthermore, four monoxenic strains of the odor producing attached cyanobacteria, Phormidium viscosum, Lyngbya allorgei, Oscillatoria splendida and Phormidium uncinatum, were isolated from submerged rocks and sediments in the lake. All of the four attached strains produced only geosmin, which was confirmed by gas chromatograph/mass spectrometer analysis, in the monoxenic cultures. In particular, we confirmed for the first time that P. viscosum, L. allorgei and P. uncinatum produced geosmin. Both the planktonic Phormidium tenue, a well known 2-methylisoborneol (MIB) producer and geosmin-producing attached cyanobacteria were closely associated with the occurrence of musty odor in Lake Kasumigaura.     

Double exposure stabilization of positive photoresist

Positive photoresists appeared to be the most promising material in VLSI microfabrication for ten or more years from now. Thus, processing know-how needs to be accumulated continuously. This work deals with thermal characteristics of positive photoresist. The following facts were declared experimentally. The quinone diazide, photosensitizer, was thermally decomposed at around 140°C to release N₂. Simultaneously the surface layer of resist film was changed into innert state, called as ‘husk’, with low gas permeability and high chemical resistance. These thermal changes in resist film affect the photoresist to SiO₂ adhesion. In this work a noble process, named double exposure stabilization, is developed to get sufficient chemical resistance and good adhesion simultaneously.     

The effect of pre-oxidation atmosphere on the durability of EB-PVD thermal barrier coatings with CoNiCrAlY bond coats

The effects of pre-oxidation heat treatment on oxidation behavior and thermal cycle life of electron-beam physical deposited (EB-PVD) thermal barrier coatings (TBCs) with CoNiCrAlY bond coats were investigated as a function of the pO₂ of the pre-oxidation atmosphere. The pO₂ of the pre-oxidation atmosphere was controlled by using a solid-state electrochemical oxygen pump system. The purity and microstructure of the continuous Al₂O₃ layer formed on the bond coat during pre-oxidation at 1050 °C were highly influenced by the pO₂ of the atmosphere. High purity α-Al₂O₃ with large grain size was formed on the bond coats under a pO₂ of 10^− 12-10^− 9 Pa, which resulted in a lower growth rate of TGO and longer lifetime.     

Intelligent decision support systems for nuclear power plants in Japan

This paper describes the MITI (Ministry of International Trade and Industry) projects for decision support systems for NPPs in Japan. Main attention is paid to the new project of an advanced man-machine system for nuclear power plants, of which a conceptual design was initiated in 1984. Some of the aspects of the design and the outline of the prototype system are discussed.     

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.     

Preventing Fatal Fractures in Carbon-Fiber–Glass-Fiber-Reinforced Plastic Composites by Monitoring Change in Electrical Resistance

A method which monitors the changes in electrical resistance in CFGFRP (carbon-fiber–glass-fiber-reinforced plastics) composites was found to be a promising technique for foreseeing fractures and preventing fatal ones. CFGFRP composites containing two types of carbon fibers along with 31.6 vol% glass fibers were used. U-shaped copper electrodes were attached to both ends of the CFGFRP composites, using a conductive adhesive agent, and electrical resistance was measured via a two-thermal dc method. A strain gauge was attached onto a specimen to measure strain. On loading, the changes in electrical resistance increased linearly with increasing strain, and the value reached 38% for the CFGFRP composites containing 0.36 vol% PAN-based high-strength carbon fibers. A tremendous change in electrical resistance was seen for the CFGFRP composites containing 0.38 vol% pitch-based high-property carbon fibers, and the composites could maintain their shape owing to a hybrid effect after the carbon fibers fractured. The change in electrical resistance can be controlled through suitable selection of the type of carbon fibers according to their values of ultimate elongation. Permanent, residual electrical resistance was found to remain, and the changes in resistance were dependent on the maximum previous strain.     

Crosstalk characteristics of a 100 km-long splicedpolarisation-maintaining optical fibre

Crosstalk of -10.1 dB in a 100 km-long spliced polarisation-maintaining optical fibre has been achieved at 1.56 μm wavelength. The fibre has been constructed from 14 125 μm-diameter PANDA fibres, with an average modal birefringence of 4.8×10^-4 , by conventional arc-fusion splice techniques. An average transmission loss of 0.37 dB/km, including the splice loss, has been obtained at 1.56 μm wavelength     

Stress analysis of a strip with a step and a crack

Stress analysis for a strip of which widths are different at the right and left handsides is carried out for before and after occurrence of a crack at a corner of a step. The strip is analyzed as a thin plate bending problem subject to transverse bending and torsion, and as a plane eleastic problem subject to bending in the plane and uniaxial tension. The rational mapping function of a sum of fractional expressions and complex variable method are used. Stress distribution and stress intensity factors are obtained.