We develop detachable "Cavitas sensors" to apply to the human oral cavity for non-invasive monitoring of saliva glucose. A salivary biosensor incorporating Pt and Ag/AgCl electrodes on a mouthguard support with an enzyme membrane is developed and tested. Electrodes are formed on the polyethylene terephthalate glycol (PETG) surface of the mouthguard. The Pt working electrode is coated with a glucose oxidase (GOD) membrane. The biosensor seamlessly is integrated with a glucose sensor and a wireless measurement system. When investigating in-vitro performance, the biosensor exhibits a robust relationship between output current and glucose concentration. In artificial saliva composed of salts and proteins, the glucose sensor is capable of highly sensitive detection over a range of 5-1000µmol/L of glucose, which encompasses the range of glucose concentrations found in human saliva. We demonstrate the ability of the sensor and wireless communication module to monitor saliva glucose in a phantom jaw imitating the structure of the human oral cavity. Stable and long-term real-time monitoring (exceeding 5h) with the telemetry system is achieved. The mouthguard biosensor will be useful as a novel method for real-time non-invasive saliva glucose monitoring for better management of dental patients.

In this paper, we discuss unique light localizations in photonic crystal line defect waveguides based on two different concepts. The first concept is an additional defect doping that breaks the symmetry of the line defect. Even though such a defect is open to the line defect, the optical field is well confined around the defect at cutoff frequencies of the line defect. This expands the design flexibility of microcavities and allows effective mode controls such as the single-mode operation. The lasing action of such cavities in a GaInAsP photonic crystal slab was experimentally observed by photopumping at room temperature. The second concept is a chirping of the waveguide structure. The photonic band of a waveguide mode has a band edge, at which the group velocity becomes zero. The band-edge condition shifts in a chirped line defect waveguide, so guided light reaches a zero group velocity point and is localized. A macroscopic behavior of this phenomenon was experimentally observed in a waveguide fabricated into a silicon-on-insulator substrate. In addition, a microscopic behavior was theoretically investigated, which suggested its applicability to a group delay device.

The spontaneous emission decay in a photonic crystal slab nanocavity with a GaInAsP quantum well active region was measured at room temperature. Even far below lasing threshold, the decay was much faster than that for the as-grown wafer. A consideration including the enhanced spontaneous emission rate by the Purcell effect, intraband relaxation of carriers, nonradiative surface recombination, spatial hole burning, and carrier diffusion enabled us to explain different decay lifetime between on-and off-resonant conditions and between different size cavities. As a result, Ͼ16-fold shorter spontaneous emission lifetime was estimated, which strongly suggests the existence of a large Purcell effect.

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A new method for analyzing polyhydroxyalkanoate (PHA) in activated sludge based on alkaline digestion followed by high-performance liquid chromatography (HPLC) was evaluated. The effects of the concentration of NaOH, reaction time, and reaction temperature were examined using activatedsludge samples containing PHA and commercially purchased PHA. To determine PHA concentrations, 0.5 mL 2 N NaOH was added to 1 mL activated-sludge mixed liquor, and the resulting mixture was heated at 105°C in a drying oven for 1 h to convert 3-hydroxybutyrate units into 2-butenoate and 3-hydroxyvalerate units into 2-pentenoate. The mixture was then acidified with 0.5 mL of 2 N H 2 SO 4 , and the solids were removed and subsequently analyzed by HPLC. The present method gave results consistent with those obtained by the conventional method of methanolysis followed by gas chromatography. The present method can facilitate investigations of PHA in activated sludge by reducing the time and labor required for analysis and by eliminating the use of organic solvents.

The effect of substrate-temperature during the deposition of lanthanum oxide on the chemical structure of lanthanum oxide/Si(100) interfacial transition layer formed between lanthanum oxide and Si-substrate was studied from the measurements of angle-resolved Si 1s, O 1s and La 3d 5/2 photoelectron spectra. In the case of the deposition at room temperature the amount of lanthanum silicate (La-silicate) was extremely small, and was not affected by the post deposition annealing (PDA) at 300°C, and increased by PDA at temperature above 500°C. On the other hand, in the case of the deposition at 300°C the amount of La-silicate increased appreciably by PDA even at 300°C. Therefore, the existence of La-silicate accelerates the formation of La-silicate by PDA.

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