1.3 μm InAsyP1-y-InPstrained-layer quantum-well laser diodes grown by metalorganic chemicalvapor deposition

The authors have fabricated 1.3-μm InAsP-InP separate-confinement-heterostructure (SCH) strained-layer double-quantum-well (SL-DQW) laser diodes (LDs) by metalorganic chemical vapor deposition (MOCVD). A low threshold current density of 410 A/cm ² was obtained. The CW threshold current was as low as 1.8 mA at 20°C, and maximum CW operating temperature of 120°C was obtained. These characteristics are almost the same as those of well-designed GaInAsP-InP SL-QW LDs. Further improvement of the characteristics of InAsP-InP LDs is expected by optimizing the device structure     

Transmittance and cathodoluminescence of AlN ceramics sintered with Ca3Al2O6 as sintering additive

Aluminum nitride ceramics were prepared by sintering with 0–4.8 mass% of Ca₃Al₂O₆ (C₃A) as a sintering additive. The transmittance in the range of 260–550 nm increased with increasing amount of C₃A. The cathodoluminescence intensity attributed to oxygen-induced defects decreased with increasing amount of C₃A. From the results, the increase of the transmittance in the range of 260–550 nm was considered to be related to the decrease of the oxygen-induced defect density.     

Lectin-like characteristics of recombinant human interleukin-1beta recognizing glycans of the glycosylphosphatidylinositol anchor

We found that 35S-labeled recombinant human interleukin-1beta (rhIL-1beta) binds phosphatidylinositol-specific phospholipase C-treated human placental alkaline phosphatase, phosphatidylinositol-specific phospholipase C-treated trypanosome surface variant glycoproteins, and urinary uromodulin immobilized on plates or immobilized on CNBr-activated Sepharose 4B. The interaction between rhIL-1beta and these glycoproteins was lectin-like, since it was inhibited in the presence of specific saccharides, i.e. mannose 6-phosphate or synthetic Ac-NH.CH2.CH2. PO4--->6Manalpha1-->(+/-2Manalpha1-->+/-6Manalpha1-->) propyl at about 1 microM. On the other hand, a wide variety of compounds including biantennary sugar chains derived from these glycoproteins as well as ethanolamine phosphate, inositol phosphate, mannose 6-sulfate, mannose 1-phosphate, glucose 6-phosphate, and mannitol 6-phosphate did not show any inhibitory effect at concentrations up to 1 mM. These results indicate that rhIL-1beta interacts with these glycoproteins via the mannose 6-phosphate diester of glycans on the glycosylphosphatidylinositol (GPI) anchor. Furthermore, when monolayers of polarized Madin-Darby canine kidney cells on polycarbonate filter membranes were incubated with 35S-rhIL-1beta in either the apical or basolateral chamber, 35S-interleukin-1beta was found to bind specifically to the apical membranes with a Ka value of 4.6 x 10(7) M-1, and the specific interaction was inhibited by 1 microM mannose 6-phosphate. Since the mannose 6-phosphate diester moiety exists only in the GPI glycans on plasma membranes, it was evident that interleukin-1beta can directly interact with the mannose 6-phosphate diester component of the intact glycan of GPI anchors on plasma membranes.     

Prostaglandin E receptor subtypes in mouse osteoblastic cell line

PGE2 is one of the key molecules in the osteoblast. It is the major prostanoid in the bone, and its production is under the control of both systemic and local factors. PGE2 has been reported to have multiple actions in the osteoblast, such as growth promotion and cell differentiation. To better understand the action of PGE2 in the osteoblast, we determined the PGE receptor subtypes in MC3T3-E1, an osteoblastic cell line derived from the normal mouse calvaria. Northern blot analysis revealed that EP1 and EP4 subtypes are expressed in MC3T3-E1. In contrast, EP3 subtype was not detected by either Northern blot analysis or RT-PCR. The contribution of each subtype was evaluated by studying the effects of subtype-specific analogs on osteoblastic function at confluency and 5 days after confluency. An EP1 agonist, 17-phenyl-omega-trinor PGE2, increased DNA synthesis and decreased alkaline phosphatase activity. 11-Deoxy-PGE1, and EP2 and EP4 agonist, decreased DNA synthesis and increased alkaline phosphatase activity at both stages. Butaprost, an EP2-selective agonist, showed effects similar to those of 11-deoxy-PGE1 only at confluency. Another and more differentiated osteoblastic marker, osteocalcin production, was detectable and was stimulated by 11-deoxy-PGE1 only 5 days after confluency. The exposure of these cells to EP1 agonist changed the cell shape to a more fibroblastic appearance. These results indicate that EP1, EP4, and probably EP2 are present in MC3T3-E1 cells; EP1 promotes cell growth, and EP2 and EP4 mediate differentiation of the osteoblast. Furthermore, the decreased response to EP2-specific agonist 5 days after confluency suggests that the expression of PGE receptor subtype is dependent on the stage of osteoblastic differentiation. This is the first report to determine PGE receptor subtypes in the bone.     

Formation of toxic aldehydes in cod liver oil after ultraviolet irradiation

Formaldehyde, acrolein, malonaldehyde (MA), acetaldehyde and propanal produced from cod liver oil upon ultraviolet irradiation (λ_max=300 nm) were derivatized into nitrogenor sulfur-containing compounds and then analyzed by capillary gas chromatography with a nitrogen-phosphorus detector or a flame photometric detector. Acrolein and MA were formed at levels of 10.9±3.06 and 190.2±38.4 nmol/mg of fish oil, respectively. Maximum levels of formaldehyde, acetaldehyde and propanal formed were 7.0±0.90, 49.1±4.5 and 35.8±4.0 nmol/mg of oil, respectively. Formation of propanal in large quantities corresponded to the high content of ɛ-3 fatty acids in cod liver oil.     

Beam test of the CsI(Tl) calorimeter for the BELLE detector at the KEK-B factory

We studied the performance of a prototype electromagnetic calorimeter for the BELLE detector at the KEK proton synchrotron for an energy range of 0.25–3.5 GeV. The prototype consisted of an array of 6 × 5 CsI(Tl) crystals with 30 cm length (16.2 radiation lengths) and about 6 cm × 6 cm cross section. The scintillation light of each CsI(Tl) crystal was read out by two large-area PIN photodiodes and charge-sensitive preamplifiers attached at the rear face of the crystal. We measured the energy and position resolution for electrons and the e/π separation for two sets of matrix configurations: one corresponded to the center and the other to the edge of the barrel calorimeter. The overall performance measured by the test proves that the prototype calorimeter is satisfactory for the use in the BELLE detector.     

Generation of adaptive gait patterns for quadruped robot with CPG network including motor dynamic model

This paper describes the generation of adaptive gait patterns using new Central Pattern Generators (CPGs) including motor dynamic models for a quadruped robot under various environments. The CPGs act as the flexible oscillators of the joints and adjust joint angles to required values. The CPGs are interconnected with each other and sets of their coupling parameters are adjusted by a genetic algorithm so that the quadruped robot can realize stable and adequate gait patterns. Generation of gait patterns results in the formation of the CPG networks suitable for the formation of not only a straight walking pattern but also of rotating gait patterns. Experimental results demonstrate that the proposed CPG networks are effective for the automatic adjustment of the adaptive gait patterns for the tested quadruped robot under various environments. Furthermore, the target tracking control based on image processing is achieved by combining the general gait patterns. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 155(1): 35–43, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20225     

Carrying capacity and vulnerability of four Asian lakes: A comparative study

To present axes for evaluating the water resources, lake environment and water use in a lake and its watershed, a comparative study was done for four East Asian lakes; lake Kasumigaura (Japan), Lake Laguna (Philippines), Lake Songkhla (Thailand) and Lake Dianchi (China). Two axes were then determined from the relationship between: (1) water use and water supply rate, and (2) water use and water quality. To clarify the meanings ‘carrying capacity’ and ‘vulnerability’, the maximum population density in the lake basin and total nitrogen concentration in the lake water were calculated and discussed to decide the direction of environmentally sound management of the drainage basin.     

Antitumor activity of 1 M tegafur-0.4 M 5-chloro-2,4-dihydroxypyridine-1 M potassium oxonate (S-1) against human colon carcinoma orthotopically implanted into nude rats

The purpose of this study was to establish a nude rat orthotopic (organ-specific) human colorectal cancer model as an in vivo secondary screen for general evaluation of new anticancer agents against colorectal cancer and to evaluate practically the antitumor activity of 1 M tegafur-0.4 M 5-chloro-2,4-dihydroxypyridine-1 M potassium oxonate (S-1), a new p.o. fluoropyrimidine, in comparison to 1 M tegafur-4 M uracil [(UFT) effective on colorectal tumor in clinical]. After implantation of KM12C, a human colorectal cancer cell line, into the subserosal layer of the colon as a single-cell suspension, extensive local tumor growth and invasion to both the mucosal and the serosal sides were observed in all rats. Metastatic foci were also formed in both lymph nodes and lungs following local tumor growth in all of them. Using this method, an equitoxic dose of S-1 (15 mg/kg/day) and UFT (30 mg/kg/day) was administered p.o. for 14 consecutive days from 7 days after tumor cell implantation. S-1 showed a higher tumor growth inhibition than UFT did [S-1, 57% (significantly different from the tumor weight of the untreated group at P < 0.05) and UFT, 18% (P > 0.05)]. When both drugs were administered to nude rats bearing KM12C injected into the cecal wall for 28 consecutive days at equitoxic doses, the mean survival in the S-1 group was 16 days longer than that in the untreated group (P < 0.01) but that in the UFT group was only 8 days longer (P > 0.05). After the administration of an equitoxic dose of both drugs, S-1 gave the higher levels than UFT in various pharmacokinetic parameters as follows: area under the curve 0-24 h of 5-fluorouracil in plasma (3.5-fold), area under the curve 0-24 h of 5-fluorouracil incorporated into RNA in the tumor (1.3-fold), and thymidylate synthase inhibition rate (percentage) in the tumor (about 20%). Collectively, these findings suggested that this orthotopic human colorectal tumor model in nude rats is useful to evaluate the clinical therapeutic efficacy of drugs or therapies for colorectal cancer, and that S-1 had a higher therapeutic effect on human colorectal tumor than UFT did.     

Taxonomy for protective ability of rust layer using its composition formed on weathering steel bridge

For a quantitative evaluation of the protectiveness of a rust layer formed on a weathering steel bridge, the relationship between the corrosion rate of the bridge and the composition of the rust layers formed on the girders was first investigated. These corrosion rates were clearly classified by the protective ability index (PAI) of α/γ^∗ and (β + s)/γ^∗, where α, γ^∗, β and s are the mass ratio of crystalline α-FeOOH, the total of γ-FeOOH, β-FeOOH and the spinel-type iron oxide (mainly Fe₃O₄), β-FeOOH and spinel-type iron oxide, analyzed by XRD, respectively. The inequality of the former index α/γ^∗ > 1 expressed the protectiveness criterion of the rust layer, while that of the latter index, (β + s)/γ^∗< 0.5 or > 0.5, classified the corrosion rate of the non-protective rust layer. The PAI is useful for a quantitative evaluation of the protectiveness of a rust layer formed on a weathering steel bridge and is an important item for the corrosion assessment of the bridge.