Error grid analysis of noninvasive glucose monitoring via gingival cerevicular fluid

In order to realize a noninvasive blood glucose monitor, we monitored the gingival cerevicular fluid (GCF). In this paper, the clinical evaluations were performed on not only normal subjects but also diabetic subjects using a GCF-glucose monitor to determine blood glucose levels. Meal load tests were carried out and the time-course changes in blood glucose level and GCF glucose level were measured continuously. A positive correlation of more than 0.9 was found between blood glucose level and GCF glucose level, necessitating the calibration of individual correlations for every subject. Finally, the performance of the GCF-glucose monitor was evaluated using Error Grid Analysis. As the results, significant information for the glucose level decision was obtained not only for normal subjects, but also for diabetic subjects.     

250 kHz spectral linewidth operation of 1.5 μm multiple quantumwell DFB-LDs

The spectral linewidth observed in a 1.5 μm multiple-quantum-well distributed-feedback laser diode (MQW-DFB-LD) with 1500 μm cavity length is discussed. The spectral linewidth was drastically reduced in long-cavity MQW-DFB0-LDs through a reduction in threshold carrier density. A spectral linewidth of 250 kHz, the narrowest ever achieved, was obtained     

Si hetero-bipolar transistor with a fluorine-doped SiC emitter anda thin, highly doped epitaxial base

The effect of fluorine doping on SiC/Si heterojunction bipolar transistors (HBTs) is studied. The film properties of the fluorine-doped SiC and device characteristics of an HBT using the SiC emitter and a 50-nm-thick, highly doped epitaxial base (10¹⁹/cm³) are presented. The current gain is improved from 15 to 80 by doping with fluorine. The current gain is four times larger than that of a conventional poly-Si emitter homo-transistor with the same base structure. In spite of the very thin base, the Early voltage is over 100 V. Forward-bias tunneling current was hardly seen at the emitter-base junction. The fluorine appears to terminate the dangling bonds. The results show the possibility of fabricating transistors with a very thin, highly doped base     

An optical FSK heterodyne dual filter detection system for takingadvantage of DFB LD applications

An optimum system configuration for an optical frequency-shift keying (FSK) heterodyne dual-filter detection system with distributed feedback laser diodes (DFB LDs) is investigated, taking into consideration LD phase noise influence. Experimental and theoretical examination show that an IF filter bandwidth greater than 10 times the beat spectral linewidth is necessary to avoid LD phase noise influence. A 301-km long-span transmission experiment has been successfully carried out with an optimum configuration for 34 Mb/s. High receiver sensitivity, -61.8 dBm with more than 10 dB improvement over the direct detection system, has also been achieved. Experimental results at higher bit rates of 140, 200, and 280 Mb/s indicate that a modulation index greater than two is desirable to avoid cross talk between mark and space signals. With sufficient frequency deviations, high receiver sensitivities of -54.7 dBm (140 Mb/s) and -52.5 dBm (200 Mb/s) have been achieved. These represent 9.6- and 9-dB sensitivity improvement, respectively, over direct detection systems. A guide for FSK dual-filter detection system design is derived from the experimental and theoretical results. Potential application regions for a dual-filter detection system with DFB LDs are determined     

Development of a directly-driven thread whirling unit with advanced tool materials for mass-production of implantable medical parts

Medical screws are a common mass-produced implantable medical component made of Titanium. To machine the threads of these types of components, thread whirling with carbide tools is typically used. However, tool wear and low cutting speed limit the productivity and increase the manufacturing cost of such medical parts. In this study, a direct motor driven thread whirling unit for an advanced Swiss-type CNC lathe was developed and it was used with advanced tool materials such as low binder content Cubic boron nitride (CBN) and Polycrystalline diamond (PCD) to find a cost-effective and more productive alternative to carbide tools.     

Preparation of mesoporous silica replica using ordered mesoporous carbon by vapor phase transport of silica source

A new vapor phase transport (VPT) technique to prepare an inverse silica replica of an ordered mesoporous carbon was developed. Tetraethyl orthosilicate (TEOS) was infiltrated in mesoporous carbon CMK-3 as the hard template at 180 °C for 48 h under an autogenous pressure in an autoclave in the presence of water. The samples obtained by removal of CMK-3 retained structural regularity of CMK-3 with little shrinkage of framework, which were characterized by SAXRD, N₂ adsorption, TG-DTA, and SEM. Influence of preparation temperature on the loading amount of silica was investigated. The multi-step replication process was monitored by characterizing the replicated materials as well as intermediate composites.     

Micro-flowers of poly(p-phenylene pyromelliteimide) crystals

Morphology control of poly(p-phenylene pyromelliteimide) (PPPI) crystals was examined using reaction-induced crystallization of oligomers during solution polymerization of self-polymerizable N-(4′-aminophenyl)-3-carboxyl-4-alkoxycarbonylphthalimide. Micro-flowers of the PPPI needle-like crystals were formed in which the needle-like crystals grew radially from the center part as petals. The molecules aligned regularly along the long axis of the needle-like crystal. The structure of alkoxy group in the monomer and the monomer concentration influenced the size of the needle-like crystals, and their average length and width were changeable from 640 nm to 1.69 μm and from 110 nm to 210 nm, respectively. The average thickness was 20 nm. The obtained micro-flowers possessed high crystallinity and exhibited excellent thermal stability.