Regulation of nerve growth mediated by inositol 1,4,5-trisphosphate receptors in growth cones

The inositol 1,4,5-trisphosphate (IP3) receptor (IP3R) acts as a Ca2+ release channel on internal Ca2+ stores. Type 1 IP3R (IP3R1) is enriched in growth cones of neurons in chick dorsal root ganglia. Depletion of internal Ca2+ stores and inhibition of IP3 signaling with drugs inhibited neurite extension. Microinjection of heparin, a competitive IP3R blocker, induced neurite retraction. Acute localized loss of function of IP3R1 in the growth cone induced by chromophore-assisted laser inactivation resulted in growth arrest and neurite retraction. IP3-induced Ca2+ release in growth cones appears to have a crucial role in control of nerve growth.     

Analysis of cationic and amphoteric surfactants: III. Structural analysis of imidazolinium cationic surfactants

Determination of the homologous distribution of imidazolinium cationic surfactants and their structural analysis have been inves-tigated. These surfactants were hydrolyzed under aqueous alkaline media, followed by acid hydrolysis to afford fatty acids and poly-amines. The resulting fatty acids were esterified with methanol, and then analyzed by gas chromatography (GC) in order to determine their homologous distribution. The obtained distribution agrees well with that of original fatty acid. Therefore, this method should be applicable to the determination of the homologous distribution of imidazolinium surfactants. The resulting polyamines were acetylated with acetic anhydride in the presence of pyridine. These acetates were analyzed by GC and isolated by preparative thin layer chroma-tography on silica gel. The structures of these isolates were identi-fied by means of 1 H-NMR and 1R spectrometry. These structural analyses demonstrated that quaternization of an imidazoline ring selectively occurred at the nitrogen at the 3-position of an imida-zoline ring, which was the kinetically favored position in terms of the steric hinderence and the stability of product.     

Synthesis of Heterocycle-Containing [60]Fullerene Derivatives

Fullerene functionalization with heterocycles is reviewed, focusing attention on cycloaddition methodology and oxidative heterocyclization.¹     

Technique of Controlling Dust Generation during Oxygen Top Blowing in BOF

Dust generation behavior during BOF operation with minimal slag was investigated by measuring the dust concentration of the dust collecting water, and a dust generation model was proposed. In this model, the dust generation rate was expressed as a function of the carbon content in metal and the dynamic pressure at a metal surface of the oxygen top blown jet. As a result of controlling the dynamic pressure with the model, the dust generation rate during BOF operation was restrained and the oxygen blowing rate was increased by 10% to raise the productivity while maintaining the same rate of dust generation. To obtain data on the dust generation rate and clarify the behavior of the top blown jet, a new online system for measuring the dust generation rate for BOF was developed. The system enabled online continuous measurement of the dust generation rate by diluting the dust collecting water and using a colorimetric method to measure the dust concentration of the diluted dust collecting water. Application of the numerical simulation method to supersonic jets was considered and the behavior of the top blown jet was grasped in order to control the dynamic pressure. These tools were used to optimize the operating conditions and quickly evaluate the top blowing lance design under the Zero‐Slag‐Process.     

Changes of infrared absorption by light soaking and thermal quenching in a-Si : H

The light- and thermal-induced changes of Si---H bonds in undoped a-Si : H have been studied on the infrared absorption of Si---H stretching mode, using the infrared photothermal deflection spectroscopy and the photothermal bending spectroscopy. The results show that the IR absorption of Si---H bonds increases by light soaking of the high power 500 mW/cm². The change of IR absorption of Si---H bonds reoccurs by thermal annealing at 200°C. This change is related to the increase of the dangling bonds under light soaking. Furthermore, we observe the change of the elasticity modulus by light soaking, using the photothermal bending spectroscopy. The structural change in a-Si : H is discussed based on these results.     

日本水权体制中的水资源配置及管理

在日本,用水单位可自由使用取水设施,干旱季节水资源的合理配置就成为一个突出的问题.目前,日本的干旱季节会有多种用水分配分式.对于KOKAI河流域的水资源分配,水的配给制度沿用了传统的方式,即地形条件占有决定性的地位,没有特殊的手段去控制水资源的公平配置.而对于YAHAGI河流域的水资源分配,各用水单位建立了一个非政府的水资源配置委员会.尽管灌溉部门掌握用水优先权,但是在严重干旱期农民会将水资源转让给供水部门.     

A damping of rotor natural vibration in three‐phase hybrid stepping motors

This paper proposes a damping method of rotor natural vibration in three‐phase hybrid stepping motors, in which optimal commutation signals are calculated from the period of the natural vibration measured by detecting the motor voltages. Moreover, an acceleration and deceleration pattern is derived from a simple model of the rotor vibration, to suppress undesirable transient oscillation in acceleration, deceleration, and positioning operations. An experimental drive system has been implemented and tested to confirm the effectiveness and versatility of the proposed method. Some experimental results show that the experimental system can damp the rotor natural vibration even if the rotor inertia varies. Compared with the conventional pattern, it is confirmed that the proposed pattern makes a great contribution to damping the undesirable transient oscillations. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 144(3): 69–77, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10153     

Measurements of 220 GHz atmospheric opacity on Mt. Fuji with a radiometer/radome system

We measured atmospheric opacity at 220 GHz at the summit of Mt. Fuji (alt. 3776 m) about one year in order to explore a feasibility of submillimeter-wave astronomical observations. For this purpose, a 220 GHz radiometer system enclosed in a radome (51×51×62 cm³) has been developed. The 220 GHz opacity was lower than 0.06 for a significant fraction (～ 45 %) of time from November 1994 to March 1995. Diurnal variation of the opacity at the summit of Mt. Fuji is so small that continuous observation at submillimeter-wave is possible through day and night. Yearly variation of the opacity is studied from water vapor pressure data measured at the weather station for the past 3 years. To prevent accumulation of ice and snow on the Gore-Tex membrane in the radome, the outer membrane was supplied with a thermal flux of 0.63 kW m^?2 and the adjacent metal radome surfaces were supplied with a flux of ～0.9 kW m^?2. We evaluate from the 220 GHz transmission data that this heat flux is sufficient to keep the membrane on the radome free of ice and snow during 83 % of the time in 5 winter months. The summit of Mt. Fuji appears to be a promising site for submillimeter-wave observations.     

Patterning of CVD diamond films by seeding and their field emission properties

Selective seeding for growing diamond on Si substrates was performed by conventional lithography using photoresist mixed with fine diamond particles. The selectivity was improved by filtering the diamond powder-photoresist mixture and carrying out reactive ion etching of patterned substrates. As a result, a selectivity up to 2.0 × 10² or higher was achieved. The resolution was of the order of 1 μm. Field emission from diamonds prepared using this selective growth method was observed without any postgrowth treatment. The measured current vs. voltage plot of a diode showed a rectifying characteristic. Under a forward bias, a current of about 15 μA was obtained at about 570 V, with a turn-on voltage of about 480 V. The emission current was comparable with that which had been observed for Si field emitter tips.     

Laterally coupled strained MQW ridge waveguide distributed-feedbacklaser diode fabricated by wet-dry hybrid etching process

The fabrication and the characteristics of the laterally coupled GaInAsP-InP quantum-well ridge waveguide distributed-feedback (DFB) lasers are presented. The electron beam (EB) lithography and the wet and dry hybrid etching technique have been used to fabricate the deep grating structures for the DFB lasers on and beside the sidewalls of the narrow ridge waveguide. The threshold current was 18.5 mA at 20°C, and the sidemode suppression ratios (SMSRs) were ensured to be more than 40 dB for as-cleaved devices with various cavity lengths. The continuous-wave output powers of over 15 mW/facet have been observed, while transverse and longitudinal modes have remained in single mode at this output level