Pharmacological properties of YM461, a new orally active platelet-activating factor antagonist

The antagonistic effect of YM461 [1-(3-phenylpropyl)-4-[2-(3-pyridyl)thiazolidin-4-ylcarbonyl]piperazine fumarate] against platelet-activating factor (PAF) was examined in severalin vitro andin vivo systems. We found that YM461 inhibited [³H]PAF binding to rabbit platelet membranes with a pK_i value of 8.90. YM461 inhibited PAF induced rabbit and human platelet aggregation with pA₂ values of 7.52 and 7.29, respectively; the slopes of the Schild plots were 1.07 and 1.01, respectively. However, YM461 at 10⁻⁴M did not affect rabbit and human platelet aggregation induced by ADP, collagen, arachidonic acid or epinephrine. YM461 inhibited PAF induced death in mice with an ED₅₀ (50% effective dose) value of 0.35 mg/kgp.o. YM461 at doses above 0.3 mg/kgi.v. inhibited PAF induced hypotension in rats. YM461 showed a dose-dependent inhibition of PAF induced hemoconcentration in rats with ED₅₀ values of 0.15 and 0.21 mg/kgp.o., respectively, at 0.5 and 1 hr after oral administration. The anti-PAF effect of YM461 persisted more than 6 hr after 3 mg/kgp.o. in rats. YM461 inhibited the bronchoconstriction induced by PAF with an ED₅₀ value of 1.2 mg/kgp.o. in anesthetized guinea pigs. Furthermore, the compound at doses above 3 mg/kgp.o. significantly inhibited antigen-induced anaphylactic asthma in conscious guinea pigs pretreated with mepyramine and propranolol. These results indicate that YM461 is a selective, potent and orally active PAF antagonist. Based on a paper presented at the Third International Conference on Platelet-Activating Factor and Structurally Related Alkyl Ether Lipids, Tokyo, Japan, May 1989.     

Asymptotic stabilization and synchronization of parametric LCR resonant circuit using the characteristics of its coefficients

In this paper, we analyze stability of a time‐varying system represented by second‐order vector differential equations based on the characteristics of their coefficient matrices. New sufficient conditions for asymptotic stability of the equilibrium points are derived. Then, an asymptotic stabilizing control method of parametric LCR resonant system is discussed by using the obtained sufficient conditions. A method synchronizing two parametric LCR resonant systems is also given. The effectiveness of the results is illustrated by numerical examples. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 154(3): 48–55, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20142     

Analysis on market deployment of photovoltaics in Japan by using energy system model MARKAL

The purpose of this paper is to make clear the conditions which can achieve the target for PV capacity attaining goal of PV system sales price assuming carbon tax and buyback in Japan. Based on the results of analysis, under expected carbon tax, PV needs subsidy for a while even if we consider both avoided cost and Green Credit. For attaining the target in 2010, PV needs more expensive buyback than that at present. After 2010 necessary subsidy decreases gradually and it becomes unnecessary in 2030. Annual income of the expected carbon tax can sufficiently cover the estimated annual subsidy.     

Electric Dipole Tracing in the Brain by Means of the Boundary Element Method and Its Accuracy

A method of localizing an electrical dipole in the brain from the scalp potential distribution has been developed with the aid of the boundary element method, in which a real geometry of the head is exactly taken into account and homogeneous electrical conductivity is assumed. Accuracy of the method was evaluated through animal experiments with a cat in which a current dipole was artificially generated in the brain. Deviation of the estimated dipole location from the true one was not random, but rather systematic (probably due to in-homogeneous conductivity distribution). It is numerically found that cavities in the skull disturb the inverse solution especially when the dipole is oriented toward the cavities. In vivo tests of the method were also done for primary somatosensory evoked potentials as a response to median nerve stimulation of a cat and myoclonic EEG. Although the homogeneous approximation was made, it does not change the significance of the results obtained by the present method.     

The catalytic steam gasification of one Australian and three Japanese coals using potassium and sodium carbonates

The catalytic steam gasification of four different coals using potassium and sodium carbonates as catalysts was carried out in a semi-flow type fixed-bed reactor. The coal was gasified with or without the catalyst under a steam—argon atmosphere at a heating rate of 50°C/s at 700–800°C. The catalytic activity of carbonates for gasification was remarkable for Japanese high-volatile coals (Miike and Takashima coals), and moderate for Australian medium-volatile coal (New Lithgow coal); however, the carbonates had little effect on gasification of Japanese lignite (Taiheiyo coal). It is assumed that Miike and Takashima coals soften and melt during the heating process to make the contact between char and catalyst better. New Lithgow and Taiheiyo coals do not have this property. Gasification was promoted significantly at lower temperatures when the catalyst was used. In both catalyzed and uncatalyzed runs the main products were hydrogen and carbon dioxide; the reaction temperature did not affect the composition of the gases much. A water—gas shift reaction occurred during gasification resulting in a large amount of carbon dioxide under a large excess of steam flow.     

Estimation of creep crack growth rate in IN-100 based on the Q* parameter concept

Since the high-strength Ni-based superalloy, cast IN-100, is considered to be brittle at high temperatures, the stable creep crack growth region is limited. Therefore, technically, it is very difficult to perform creep tests and there are few experimental results on the creep crack growth behaviour of this material. We performed creep crack growth tests using Ni-based superalloy, cast IN-100, and derived the Q* parameter for this material, which characterizes the creep crack growth rate. Using this Q* parameter, we derived a law for the creep rupture life of this material.     

Simulation of VDE under intervention of vertical stability control and vertical electromagnetic force on the ITER vacuum vessel

Vertical displacement events (VDEs) and disruptions usually take place under intervention of vertical stability (VS) control and the vertical electromagnetic force induced on vacuum vessels is potentially influenced. This paper presents assessment of the force that arises from the VS control in ITER VDEs using a numerical simulation code DINA. The focus is on a possible malfunctioning of the ex-vessel VS control circuit: radial magnetic field is unintentionally applied to the direction of enhancing the vertical displacement further. Since this type of failure usually causes the largest forces (or halo currents) observed in the present experiments, this situation must be properly accommodated in the design of the ITER vacuum vessel. DINA analysis shows that although the ex-vessel VS control modifies radial field, it does not affect plasma motion and current quench behavior including halo current generation because the vacuum vessel shields the field created by the ex-vessel coils. Nevertheless, the VS control modifies the force on the vessel by directly acting on the eddy current carried by the conducting structures of the vessel. Although the worst case was explored in a range of plasma inductance and pattern of VS control in combination with the in-vessel VS control circuit, the result confirmed that the force is still within the design margin.     

Electrical and thermal conductivities of porous SiC/SiO2/C composites with different morphology from carbonized wood

Porous SiC/SiO₂/C composites exhibiting a wide range of high thermal and electrical conductivities were developed from carbonized wood infiltrated with SiO₂. As a pre-treatment, the samples were either heated at 100 °C or kept at room temperature followed by sintering in the temperature range 1200–1800 °C. The microstructure, the morphology, and the electrical and thermal conductivities of the composites were investigated. Pre-treatment at room temperature followed by sintering up to 1800 °C produced composites exhibiting a greater size of carbon crystallites, a higher ordering of the microstructure of carbon and β-SiC and a smaller amount of SiO₂, resulting in electrical and thermal conductivities of 1.17 × 10⁴ Ω⁻¹ m⁻¹ and 25 W/mK, respectively. The thermal conductivity could be further improved to 101 W/mK by increasing the density of the composite to 1.82 g/cm³. In contrast, the pre-treatment at 100 °C produced composites possessing a lower thermal conductivity of 2 W/mK.     

Output power characteristic of WEC for a buoy

Floating devices, such as a cavity resonance device, take advantage of both the water motion and the wave induced motions of the floating body itself. In the design of a wave energy converter (WEC), the most significant factor is that an optimum length of the internal water column should exists, that is, a length in which maximum power is converted near the heaving resonance. A theoretical analysis of this power generated by a pneumatic-type WEC is performed, and the results obtained from the analysis are used for a real WEC for a buoy. The length of the internal water column corresponds to that of the water mass in the water column. If designed properly, a WEC can take advantage not only of the cavity resonance but also of the heaving motion of the buoy. This paper presents the test results of the generation characteristic of a WEC and the harmful effect of fouling in the internal water column. The results are then applied to the design of a WEC for a buoy. This paper was recommended for publication in revised form by Associate Editor Jae Young Lee Jin-Seok Oh was born in Kyung-Nam, Korea. He received the B. E. degree in Marine Engineering from Korea Maritime University in 1983. Since 1983, he has been with the Zodiac (England Company) including early 4 years of System Engineer. He received the M.E. and Ph. D. degrees from Korea Maritime University, Busan, Korea in 1989 and 1996, respectively. He had been with the Agency for Defense Development (ADD) as a researcher from 1989 to 1992. In 1996, he joined the Division of Mechatronics Engineering at Korea Maritime University. His research interests include electrical drive systems, robot control and PC-based Control applications.     

Construction of virtual patient model for maxillofacial palpation training system

Palpation has been considered as one of the important diagnostic skills for doctors, which is conducted on a patient to identify the size, the consistency, and the location of a subcutaneous tumor. Accurate palpation skill often detects the cause of disease early. Even in the field of dentistry, palpation has been considered as the important diagnostic skill for dentists. By the way, any practical training of palpation against a patient did not implemented in the dental education because the patient safety has a priority more than its educational effect. Then we propose a training system for maxillofacial palpation by using virtual reality and haptic interface. The details of modeling a virtual patient model for the training system are shown in this paper, and the experimental results are also described.