An HTS 21-pole microstrip filter for IMT-2000 base stations with steep attenuation

We developed a 21-pole high-temperature superconductor thin-film microstrip filter with steep attenuation. This filter is applicable in the International Mobile Telecommunications-2000 (IMT-2000) base station receiver system, where high selectivity is needed to avoid interference from signals in the personal handyphone system (PHS) band just below the IMT-2000 band. The out-of-band rejection of this filter 1 MHz below the passband edge is more than 40 dB. Owing to the improvements of the design and the fabrication processes, we also eliminated the need for a tuning process in the fabrication processes in order to reduce the production costs and the turnaround time.     

Influence of molecular structure on propagation of positive streamer discharge in dielectric liquids

In this paper, streamer discharges in dielectric liquids which have various molecular structures, such as a double bond or a triple bond in the molecular formula, are observed in detail for positive point polarity under the application of an impulse voltage to the point electrode. As test liquids, four straight‐chain hydrocarbon liquids—n‐hexane, n‐heptane, n‐octane, and n‐decane—are selected and in addition the influence of a double or triple bond included in their molecular formula on the propagation of positive streamers is investigated in detail by simultaneously using a high‐speed schlieren method and an LED current measurement system. Some differences in the mean propagation velocity and the propagation shape of positive streamers are evident. Their shape is mainly filamentary in test liquids including a double or triple bond. Also, positive streamer propagation is promoted in these liquids. It is thought that this is due to the effect of π bonds which have smaller bond energies than σ bonds. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 149(1): 15–21, 2004; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10366     

Distribution and metabolism of F6-1,25(OH)2 vitamin D3 and 1,25(OH)2 vitamin D3 in the bones of rats dosed with tritium-labeled compounds

26,26,26,27,27,27-Hexafluo-1,25(OH)2 vitamin D3, the hexafluorinated analog of 1,25(OH)2 vitamin D3, has been reported to be several times more potent than the parent compound regarding some vitamin D actions. The reason for enhanced biologic activity in the kidneys and small intestine appears to be related to F6-1,25(OH)2 vitamin D3 metabolism to ST-232, 26,26,26,27,27,27-hexafluoro-1 alpha, 23S,25-trihydroxyvitamin D3, a bioactive 23S-hydroxylated form that is resistant to further metabolism. Since F6-1,25(OH)2 vitamin D3 is considered to prevent osteoporotic decrease in bone mass by suppressing bone turnover, we here compared the distribution and metabolism of [1 beta-3H]F6-1,25(OH)2 vitamin D3 and [1 beta-3H]1,25(OH)2 vitamin D3 in bones of rats by autoradiography and radio-HPLC. In the dosed groups, radioactivity was detected locally in the metaphysis, the modeling site in bones. As compared with the [1 beta-3H]1,25(OH)2 vitamin D3 case, [1 beta-3H]F6-1,25(OH)2 vitamin D3 was significantly retained in this site, and moreover, it mainly persisted as unchanged compound and ST-232. These findings indicate that the reason for the higher potency of F6-1,25(OH)2 vitamin D3 than 1,25(OH)2 vitamin D3 in bones are linked with increased distribution and reduced metabolism.     

An approach for assaying benzodiazepine receptor binding with radioiodinated ligand: 125I-labeled diazepam derivative

[125I]2'-Iododiazepam (IDZ) was prepared and its application in a benzodiazepine receptor binding assay was studied. [125I]2'-IDZ binds to the rat cortical membrane with a high affinity (Kd, 0.66 nM). Various benzodiazepines showed competition with [125I]2'-IDZ for the binding sites in the rat cortical membrane, and the specificity of its binding correlated well with that of [3H]diazepam (r = 0.992, p < 0.001). These findings suggested that [125I]2'-IDZ binds to the same sites as [3H]diazepam and indicated that [125I]2'-IDZ can be used in a benzodiazepine receptor assay.     

Morphology control of ZnO crystalline particles in aqueous solution

We developed an aqueous solution process to synthesize crystalline ZnO particles and control their morphology. ZnO crystals were prepared in an aqueous solution containing zinc acetate and ammonia at 50 °C with no additional phase. ZnO particles having long hexagonal cylinder, short hexagonal cylinder, rounded hexagonal cylinder, rounded ellipse, pointed ellipse or multi-needle shapes were homogeneously nucleated and precipitated in solution. Crystal growth and preferential growth faces were controlled by solution conditions. Morphological control techniques in this system will contribute to the development of solution chemistry for inorganic materials and future oxide devices.     

Design of an osteoinductive biodegradable cell scaffold based on controlled release technology of bone morphogenetic protein

Biodegradable gelatin sponges with or without 50 wt% of ß-tricalcium phosphate (ß-TCP) incorporation were fabricated to design an osteoinductive scaffold that is capable of the controlled release of bone morphogenetic protein (BMP)-2. The sponges prepared had an interconnected pore structure with an average pore size of 200 μm, irrespective of the ß-TCP incorporation. When seeded into the sponge by an agitated method, mesenchymal stem cells (MSC) isolated from rat bone marrow were homogeneously distributed throughout the sponge. Osteogenic differentiation experiments demonstrated that the in vitro differentiation and proliferation of MSC was enhanced by ß-TCP incorporation. The in vivo osteoinduction activity of gelatin or ß-TCP-incorporated gelatin sponges containing BMP-2 was studied in terms of histological and biochemical examinations following the implantation into the back subcutis of rats. As a result, homogeneous bone formation was histologically observed inside the sponge implanted, although the gelatin sponge exhibited significantly higher osteoinduction activity than that of the gelatin sponge incorporating ß-TCP. The in vivo release test revealed that BMP-2 was released from the sponge in vivo, in a similar time period, whether or not ß-TCP was incorporated. BMP-2 was retained for a time period longer than 28 days. These results suggest that the gelatin sponge with an ability to release BMP-2 is a promising cell scaffold for osteoinduction in vivo, although the effect of ß-TCP incorporation on the osteoinductivity of sponges was different between the in vitro and in vivo systems.     

Low-temperature fabrication of porous and transparent ZnO films with hybrid structure by self-hydrolysis method

Porous, transparent and controllable ZnO nanoparticulate films were fabricated by self-hydrolysis of zinc salts in its crystalline water without any additions at 65 °C by an evaporating acetone solvent. The crystallite size of ZnO nanoparticles was about 30 nm, and the thickness of the nanoparticle film was controllable by simply changing the coating times. ZnO nanoparticulate films in thickness of 500 nm showed a high transmittance (>90%) in the visible range and widen bandgap (3.35 eV). The c-axis oriented ZnO nanoarray film was fabricated by a subsequent heterogeneous nucleation and growth in an aqueous solution. As-grown ZnO hybrid films showed a good transmittance (>85%) in the visible range.