Measurement of heart rate variability and stress evaluation by using microwave reflectometric vital signal sensing

In this paper, we present two robust signal processing techniques for stress evaluation using a microwave reflectometric cardiopulmonary sensing instrument. These techniques enable the heart rate variability (HRV) to be recovered from measurements of body-surface dynamic motion, which is subsequently used for the stress evaluation. Specifically, two novel elements are introduced: one is a reconfiguration of the HRV from the cross-correlation function between a measurement signal and a template signal which is constructed by averaging periodic component over a measurement time. The other is a reconstruction of the HRV from the time variation of the heartbeat frequency; this is evaluated by a repetition of the maximum entropy method. These two signal processing techniques accomplish the reconstruction of the HRV, though they are completely different algorithms. For validations of our model, an experimental setup is presented and several sets of experimental data are analyzed using the two proposed signal processing techniques, which are subsequently used for the stress evaluation. The results presented herein are consistent with electrocardiogram data.     

Ultra-high-sensitive extraction-photometric determination of sodium ion using flow injection analysis with a chromogenic calix[4]arene derivative and a laser interferometric photothermal detector

A novel flow injection analysis (FIA) system for ultra-high-sensitive determination of Na(+), which involves laser interferometric photothermal equipment as the detector, was designed using a proton-dissociable chromogenic calix[4]arene derivative with a dinitrophenol moiety as the extraction-photometric reagent. The chromogenic calix[4]arene derivative showed an excellent extractability toward Na(+), which reflected the cation-complexing property of the tetraethyl ester derivative of calix[4]arene. As the calibration graph of the Na(+) concentration could be successfully obtained at the nanomolar level by this method, the proposed FIA system was found to be promising for highly sensitive determination of Na(+) in very dilute samples such as supply water and cooling water in power plants.     

Subwavelength resist patterning using interference exposure with a deep ultraviolet grating mask: Bragg angle incidence versus normal incidence

Interference lithography using a deep-ultraviolet (DUV) laser is instrumental in the manufacture of subwavelength patterns used at visible wavelengths. We investigated a grating mask strategy for exposure in terms of how to set and illuminate masks. To obtain high aspect ratio patterns, high fringe visibility, and high exposure uniformity are essential, and for that purpose the use of only two beams with liquid immersion is necessary but not sufficient. It needs to be addressed whether the grating should face air or liquid to achieve index matching without affecting its beam-splitting properties. Currently, the most feasible solution to produce sub-200 nm periods requires the use of a fused-silica grating under Bragg geometry (not normal incidence geometry) and filling the gap between the grating and resist with a high-index liquid.     

Graphene growth on a Pt(111) substrate by surface segregation and precipitation

We report on the fabrication of a sizable graphene sheet on a carbon-doped Pt(111) substrate through surface segregation and precipitation. Scanning Auger electron spectroscopy (AES) reveals that the graphene covered more than 98% of the substrate surface. Our graphene consists of single-layer graphene across the substrate with fractions of several micrometer wide bi- and tri-layer graphene islands. We also show that the number of graphene layers can be precisely determined by analyzing AES data. While Raman spectroscopy is usually used to study graphene on SiO?, we show that AES is a powerful tool to characterize graphene grown on metal substrates.     

Biodistribution of aqueous suspensions of carbon nanotubes in mice and their biocompatibility

In this study, we prepared two-types of water-dispersible carbon nanotubes (CNTs) and investigated their biodistribution in mice as well as bio-/cyto-compatibility. After administration, their organs were excised at various post-injection times, then observed using both optical and transmission electron microscopy (TEM). The color of the liver and lung markedly darkened, suggesting that administered CNTs reached these organs. By TEM observation, the CNTs were found in the liver and lung. They were observed even in the kidney and spleen, though their distributions in those organs were very low compared with that in liver and lung. Therefore, most of the administered CNTs would be accumulated in the liver or lung. However, the time profile of the body weight of CNT-administered mice was close to that of control mice. In addition, we estimated the cytocompatibility of the water-dispersible CNTs for hepatocytes. According to a TNF-alpha assay of the cells cultured with CNTs, the expression level was almost the same as that of the control. These results suggested that the water-dispersible CNTs have good bio-/cyto-compatibility under this condition.     

Inactivation of Lactobacillus fructivorans in physiological saline and unpasteurised sake using CO2 microbubbles at ambient temperature and low pressure

The ability of carbon dioxide microbubbles (MB‐CO₂) to inactivate Lactobacillus fructivorans suspended in physiological saline and unpasteurised sake at ambient temperature and a pressure lower than 2.0 MPa was investigated. The number of L. fructivorans cells in physiological saline solution containing 15% ethanol showed a 6‐log reduction following MB‐CO₂ treatment at 40 °C and 2.0 MPa for 50 min. The effectiveness of the treatment increased concomitantly with temperature, pressure and ethanol concentration of the sample solution but was unaffected by the glucose concentration in the sample solution. Furthermore, the number of L. fructivorans cells showed a 5‐log reduction in sake after MB‐CO₂ treatment at 40°C and 2.0 MPa for 60 min. Sensory evaluation revealed no significant difference between MB‐CO₂‐treated sake and unpasteurised sake. These results indicated that MB‐CO₂ treatment was highly effective for the inactivation of L. fructivorans and might become a practical method for pasteurising sake at ambient temperature.     

Analytical Methods for Virus Detection in Water and Food

Potential ways to address the issues that relate to the techniques for analyzing food and environmental samples for the presence of enteric viruses are discussed. It is not the authors?? remit to produce or recommend standard or reference methods but to address specific issues in the analytical procedures. Foods of primary importance are bivalve molluscs, particularly, oysters, clams, and mussels; salad crops such as lettuce, green onions and other greens; and soft fruits such as raspberries and strawberries. All types of water, not only drinking water but also recreational water (fresh, marine, and swimming pool), river water (irrigation water), raw and treated sewage are potential vehicles for virus transmission. Well over 100 different enteric viruses could be food or water contaminants; however, with few exceptions, most well-characterized foodborne or waterborne viral outbreaks are restricted to hepatitis A virus (HAV) and calicivirus, essentially norovirus (NoV). Target viruses for analytical methods include, in addition to NoV and HAV, hepatitis E virus (HEV), enteroviruses (e.g., poliovirus), adenovirus, rotavirus, astrovirus, and any other relevant virus likely to be transmitted by food or water. A survey of the currently available methods for detection of viruses in food and environmental matrices was conducted, gathering information on protocols for extraction of viruses from various matrices and on the various specific detection techniques for each virus type.     

A novel approach to deliverable power in low‐voltage DC distribution system on the basis of voltage stability

This paper proposes that a deliverable power through a low‐voltage DC distribution system has an upper limitation. The upper limitation of the deliverable power, P_lim, is explained on the basis of a voltage instability phenomenon occurring for the load with a voltage sensitivity below 1. From theoretical‐calculation results, it is pointed out that P_lim diminishes with augment in the distribution‐line length. This phenomenon becomes more distinct for the higher distribution‐line inductance per unit length. Connection of the capacitor to the receiving end of the distribution line is discussed as a method for rising P_lim. Measurements of the voltage waveform at the load terminals successfully support P_lim derived from the theoretical calculation. © 2011 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Efficient Outdiffusion of Hydrogen from Mg-Doped Nitrides by NF<Subscript>3</Subscript> Annealing

High concentration (more than 1 × 10¹⁸ cm⁻³) of hydrogen atoms remaining in Mg-doped GaN epitaxial layers grown by metalorganic chemical vapor deposition even after conventional annealing in N₂ ambient could induce degradation in GaN-based devices containing Mg-doped layers. In this study, by annealing Mg-doped nitrides in NF₃ ambient, we successfully reduced residual hydrogen below mid-10¹⁷ cm⁻³, which is much smaller than by N₂ annealing. NF₃ annealing enhances outdiffusion of hydrogen from the bulk, which is possibly because the nitrogen and fluorine radicals decomposed from NF₃ accelerate desorption of hydrogen adatoms from the surface. The proposed method for Mg activation would improve the reliability of GaN-based light-emitting diodes and laser diodes.     

Synthesis of Polyaniline/Pd Nanoparticles via Ligand Exchange

Polyaniline/Pd nanoparticles were synthesized via ligand exchange. Pre-prepared water soluble starch/Pd nanoparticles were treated with polyaniline, and washed with water, leading to the small and well-dispersed polyaniline/Pd nanoparticles. The redox state of polyaniline was preserved during the ligand exchange reaction.