Enzymatic assay with detection by enhanced luminol chemiluminescence in a reversed micellar system: determination of l-amino acids and glucose

A detection system for hydrogen peroxide, i.e., luminol chemiluminescence (CL) in a hexadecyltrimethylammonium bromide (CTAB) reversed micellar system, was coupled to enzyme reactions. The use of CTAB reversed micellar medium allows one to conduct both the oxidase enzymatic and CL detection reactions simultaneously at mild pH (l-amino acid system, pH 8.7; glucose system, pH 8.5) in the absence of any co-oxidant or catalyst. Based on this result, simple and unique determinations of l-amino acids and glucose as substrates were developed. The calibration graph for a representative amino acid, l-phenylalanine, was linear in the concentration range 4.0×10^?6?200×10^?6M with a relative standard deviation of 5.78% (five determinations). The method established for l-phenylalanine was also applicable for the assay of fourteen other l-amino acids. The calibration graph for glucose was linear in the concentration range 5.4×10^??540×10^?6M with a relative standard deviation of 4.27% (eight determinations). This method was compared with a standard spectrophotometric method (hexokinase) and successfully applied to the determination of glucose in human serum.     

Direct conversion of a metal organic compound to epitaxial Sb-doped SnO2 film on a (0 0 1) TiO2 substrate using a KrF laser, and its resulting electrical properties

Epitaxial Sb-doped SnO₂ (0 0 1) thin film on a TiO₂ (0 0 1) substrate was successfully prepared by laser-assisted metal organic deposition at room temperature. The effects of the precursor thin film and laser fluence on the resistivity, carrier concentration, and mobility of the Sb-doped SnO₂ film were investigated. The resistivity of the Sb-doped SnO₂ film prepared by direct irradiation to metal organic film is one order of magnitude lower than that of film prepared by irradiation to amorphous Sb-doped SnO₂ film. From an analysis of Hall measurements, the difference between the resistivity of the Sb-doped SnO₂ film prepared using the metal organic precursor film and that of amorphous precursor film appears to be caused by the mobility. Direct conversion of the metal organic compound by excimer laser irradiation was found to be effective for preparing epitaxial Sb-doped SnO₂ film with low resistivity.     

All-Fiber Optical Add-Drop Multiplexer Using a Pair of Fiber Grating Couplers

A new all-fiber optical add-drop multiplexer (ADM) using a pair of fiber grating couplers (FGCs) was proposed and first demonstrated. It was theoretically and experimentally shown that both drop and add efficiencies could be maximized in the proposed ADM. It was also clarified that the crosstalk between dropped and added signals could be improved in the proposed ADM compared with that in the single FGC. Drop and add operations in the ADM for 3-channel WDM signals with 1.6 nm wavelength spacing were confirmed. The ADM with signal amplification ability, which consists of a pair of FGCs, an EDF, and a pump-LD, was proposed and demonstrated. It was confirmed that the dropped and transmitted optical signals could be amplified in the ADM, and would be able to expand fiber routing spans.     

An ASE Reduction Filter Using Cascaded Optical Fiber Grating Couplers in EDFA Repeater

A new configuration for an ASE reduction filter in EDFA repeaters for WDM optical transmission systems using optical fiber grating couplers (FGCs) was proposed and first demonstrated. The filtering characteristics of the proposed filter for amplified single wavelength signal and 2-channel WDM signals using EDFA were identified. It was found that the filter was effective to improve SNR in optical domain by reducing ASE noise. The required FGC characteristics for the filter were theoretically predicted under the condition that the total filter loss did not exceed 3 dB. More than 70% of drop efficiency was required in each FGC for the application of the proposed filter to an 8-channel WDM system using EDFA repeaters.     

Analysis of Spectral Reflectance Using Normalization Method from Endoscopic Spectroscopy System

Objective assessment of gastrointestinal mucosal color is extremely important in the endoscopic diagnosis of digestive tract disease. In this paper, we propose a method to clarify the spectral characteristics of gastric and colon cancer. A large number of spectral reflectance data of mucous membrane are measured by the endoscopic spectroscopy system (ESS) in the National Cancer Center Hospital East, Kashiwa, Japan and the Department of Internal Medicine, Self-Defense Force Center Hospital, Tokyo, Japan. We assume that early cancer appears primarily in the spectral data of short wavelength, because it is usually present in a superficial cell where short wavelength light is scattered more strongly than long wavelength light. To identify the features in the short wavelength components, the spectral reflectance was divided by the reflectance of a long wavelength. We investigated the possibility of distinguishing early cancer from normal spectral data through statistical analysis, employing the projection axis as the mean difference between them. Early cancer and normal spectral data were projected on the projection axis, and the Student’s T-test was applied to evaluate the mean of the distribution between these data.     

Velocity spectrum for non-Markovian Brownian motion in a periodic potential

Non-Markovian Brownian motion in a periodic potential is studied by means of an electronic analogue simulator. Velocity spectra, the Fourier transforms of velocity autocorrelation functions, are obtained for three types of random force, that is, a white noise, an Ornstein—Uhlenbeck process, and a quasimonochromatic noise. The analogue results are in good agreement both with theoretical ones calculated with the use of a matrix-continued-fraction method, and with the results of digital simulations. An unexpected extra peak in the velocity spectrum is observed for Ornstein-Uhlenbeck noise with large correlation time. The peak is attributed to a slow oscillatory motion of the Brownian particle as it moves back and forth over several lattice spaces. Its relationship to an approximate Langevin equation is discussed.