High-power, wide-temperature range operation of 1.3-/spl mu/m gain-coupled DFB lasers with automatically buried InAsP absorptive grating

DFB lasers operating at 1.3 /spl mu/m with gain-coupling structure show single-mode operation over a wide temperature range of -20/spl sim/85/spl deg/C and up to a high power of 130 mW. These lasers have InAsP absorptive grating, which can be formed by a substantially simplified fabrication process, involving annealing a corrugated InP substrate in an atmosphere of mixed arsine and phosphine.     

Mutagenicity of ozonation and chlorination products from p-hydroxybenzaldehyde

p-Hydroxybenzaldehyde, a component of soil humic substances, was ozonated and chlorinated. The ether extract and the residue were subjected to the Ames assay; mutagenic activities were identified. The non-ionic resin CSP800 and the anion exchange resin CHPA25 were used for separation of mutagenic compounds. The compounds in the water layer were not adsorbed on CSP800 or CHPA25 and exhibited strong mutagenic activity. Mutagenic activity was reduced as the added chlorine was increased. Ether extracts were analyzed by gas chromatography-mass spectrometry (GC-MS) and chloral, 1,3-dichloro-2-propanone, 1,2,3-trichloro-1-propene, tetrachloroethylene and 1,1,1,3,3-pentachloro-2-propanone were identified as mutagenic compounds.     

Protein degradation by ERp72 from rat and mouse liver endoplasmic reticulum

The endoplasmic reticulum (ER) resident protein, ER60, is a member of the protein disulfide-isomerase family and contains two copies of the internal thioredoxin motif, CGHC. Previously, ER60 was identified as a cysteine protease and named ER-60 protease (Urade, R., Nasu, M., Moriyama, T., Wada, K., and Kito, M. (1992) J. Biol. Chem. 267, 15152-15159; Urade, R., and Kito, M. (1992) FEBS Lett. 312, 83-86). Here, ERp72, the other member of the protein disulfide-isomerase family containing three CGHC motifs, was isolated from ER of rat and mouse livers through four sequential chromatographies on DEAE-Toyopearl 650, AF-heparin Toyopearl 650M, and TSK gel G3000SW twice. The purified rat protein was found to be homogeneous on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, not being contaminated by ER-60 protease, as judged on immunoblot analysis using an anti-ER-60 protease antibody. The partial amino acid sequence of rat ERp72 was 93% homologous to that of mouse ERp72. The purified rat ERp72 degraded other ER resident proteins such as protein disulfide-isomerase and calreticulin. The purified mouse ERp72 also degraded those proteins. Though rat ERp72 did not basically require Ca2+ for the reaction, the degradation of protein disulfide-isomerase was enhanced, but the degradation of calreticulin was inhibited in the presence of Ca2+. The proteolytic activity of rat ERp72 was inhibited by cysteine protease inhibitors. Its sensitivity to protease inhibitors was the same as that of ER-60 protease. In addition, the proteolytic activity of rat ERp72 was inhibited by acidic phospholipids, also similar to ER-60 protease. Therefore, we propose that ERp72 be named ER-72 protease.     

Differential expression of c-fos mRNA in rat prefrontal cortex, striatum, N. accumbens and lateral septum after typical and atypical antipsychotics: an in situ hybridization study

The regional difference in the expression of c-fos mRNA induced by typical and atypical antipsychotics was determined in prefrontal cortex, striatum, N. accumbens and lateral septum in rats by in situ hybridization. Two typical antipsychotics, haloperidol (2 mg/kg) and fluphenazine (2 mg/kg), and three atypical antipsychotics, (-)sulpiride (100 mg/kg), clozapine (20 mg/kg) and OPC-14597 (40 mg/kg), were used. Brains were fixed with 4% paraformaldehyde 45 min after drug administration (i.p.). Brain sections of 30 microns-thickness were made in a cryostat and hybridized with 35S-labelled for c-fos oligonucleotide probe. These sections were apposed to X-ray films and the autoradiograms were semi-quantitatively analysed by computer-assisted densitometry. All antipsychotics used increased c-fos mRNA expression in N. accumbens shell, a region of the forebrain associated with limbic systems. On the other hand, two typical antipsychotics (haloperidol and fluphenazine) that cause a high incidence of acute motor side effects increased the expression of c-fos mRNA in the dorsolateral striatum, an extrapyramidal region primarily involved in motor control. Only clozapine induced c-fos mRNA in the medial prefrontal cortex and lateral septum. These results strongly suggest that the shell region of N. accumbens may be a common site of therapeutic action of antipsychotics.     

Mean systemic pressure and mean pulmonary pressure: their effects on the total artificial heart

Mean systemic pressure (MSP) and mean pulmonary pressure (MPF), which are mean driving pressures for venous return in the natural heart, were studied in 11 calves in which the natural heart had been replaced with a total artificial heart (TAH). They were measured simply by stopping the artificial heart pumping. Although blood translocation from the arterial to the venous side was not performed, the eventual right and left atrial pressures reached six to eight seconds after stopping the TAH would represent MSP and MPP with reasonable accuracy. The MSP varied from nine to 3k mmHg (20+/-6 mmHg), whereas the MPP varied from nine to 39 mmHg (22+/-7 mmHg). The MSP varied in close relation to the right atrial pressure prior to cessation of the TAH (r=0.9124). Increases in RAP and MSP were mainly attributed to an increase in circulating blood volume. In the performance of the TAH, MSP (or MPP), proper diastolic duration and vacuum application during diastole was of prime importance in determining the end-diastolic ventricular volume.     

Infrared sensors using poly‐Si thin‐film transistors for proximity sensors integrated in smartphone displays

We have developed infrared sensors using poly‐Si thin‐film transistors (TFTs) for proximity sensors integrated in smartphone displays. Initially, we evaluate the infrared sensitivities of the poly‐Si TFTs, and it is found that a pin‐type TFT is suitable for the infrared sensors. Next, we propose three types of the infrared sensors. First, an analog current detection‐type sensor has a simple structure, and it is found that it can detect presence of a hand. Second, a lock‐in detection‐type sensor has tolerance against ambient light, and it is found that it can detect a target signal under noise signals. Third, a frequency detection‐type sensor has an advantage that only a digital circuit is necessary for detection, and it is found that it can detect the infrared intensity because the oscillation frequency increases monotonically with the intensity. We can utilize these infrared sensors on demand.     

Manufacture of organic transistors on large‐area flexible substrate using direct imaging exposure system by wet process suitable for roll‐to‐roll production

Organic thin‐film transistors (OTFTs) can be fabricated via a wet process and have exceptionally high flexibility. Therefore, production using the roll‐to‐roll (RtoR) method is expected. We succeeded in developing a new OTFT wet fabrication process adaptable to the RtoR process. Utilizing the electroless plating method for wiring formation, all materials can be formed in a wet process and can be patterned using the photolithography process. In addition, we succeeded in fabricating OTFT on an A4‐type flexible substrate using RtoR direct imaging exposure system.     

Short‐circuit phenomenon through hot gas ejected from molded case circuit breakers during high current interruption process and prevention of its occurrence

An experimental investigation on short‐circuit phenomenon through ejected hot gas between source‐side terminals in molded case circuit breakers (MCCBs) was performed. The rate of occurrence of the short‐circuit phenomenon was found to increase with the peak value of the breaking current and with the order of the breaking test. The conductance of the ejected hot gas was also found to rise with the peak value of the breaking current and with the order of the breaking test. These results indicate that the hot gas of high conductance is the cause of the short‐circuit phenomenon. Some effective means were taken in the MCCB to reduce the conductance of the hot gas. Decreasing the conductance of the hot gas successfully prevented the occurrence of short‐circuit phenomenon. © 2000 Scripta Technica, Electr Eng Jpn, 132(1): 22–29, 2000     

Detection of CpG Methylation in G-Quadruplex Forming Sequences Using G-Quadruplex Ligands

Genomic DNA methylation is involved in many diseases and is expected to be a specific biomarker for even the pre-symptomatic diagnosis of many diseases. Thus, a rapid and inexpensive detection method is required for disease diagnosis. We have previously reported that cytosine methylation in G-quadruplex (G4)-forming oligonucleotides develops different G4 topologies. In this study, we developed a method for detecting CpG methylation in G4-forming oligonucleotides based on the structural differences between methylated and unmethylated G4 DNAs. The differences in G4 topologies due to CpG methylation can be discriminated by G4 ligands. We performed a binding assay between methylated or unmethylated G4 DNAs and G4 ligands. The binding abilities of fluorescent G4 ligands to BCL-2, HRAS1, HRAS2, VEGF G4-forming sequences were examined by fluorescence-based microtiter plate assay. The differences in fluorescence intensities between methylated and unmethylated G4 DNAs were statistically significant. In addition to fluorescence detection, the binding of G4 ligand to DNA was detected by chemiluminescence. A significant difference was also detected in chemiluminescence intensity between methylated and unmethylated DNA. This is the first study on the detection of CpG methylation in G4 structures, focusing on structural changes using G4 ligands.