Metabolic responses of plant cell culture to hydrodynamic stress

The metabolic responses of eucalyptus and safflower cells to hydrodynamic stress in a 550-cm³ stirred tank reactor were investigated. At 0.5 — 2.3 m²/s³ of energy dissipation rate, the decreases in respiration rate and ATP content were larger than the decrease in the membrane integrity. Intracellular NAD(P)H was decreased and cytosolic calcium content was increased by agitation. EGTA, verapamil and W-7 suppressed the decrease in NAD(P)H. These results suggest that the cytosolic calcium, as a second messenger, mediate the signal of the hydrodynamic stress into the metabolism which induces the decrease in respiration rate. Furthermore, a decrease in the filamentous actin content due to agitation was observed.     

Heat transfer in the flow through a bundle of tubes and transitions of the flow

Heat transfer in the flow through a bundle of heated tubes are investigated numerically at Reynolds numbers around which the flow makes a transition from a steady state to an oscillatory one, as a model of micro heat exchanger. It is found that physical quantities such as the Nusselt number and the pressure loss exhibit discontinuous jumps with continuous change in the Reynolds number. The origin of the sudden changes in these physical quantities is identified to come from the existence of multiple stable solutions which leads to hystereses in these quantities.     

Novel deposition method of anti-reflective coating for spherical silicon solar cells

The liquid-phase deposition (LPD) as a novel deposition method of anti-reflective coating (ARC) for spherical silicon solar cells has been proposed. The LPD is a growth method in aqueous solution and can deposit thin films with uniform coverage over a spherical surface. The solar cell performance of the spherical silicon solar cell with an ARC shows more than 10% increase in short-circuit current density compared to that without an ARC. The result confirms that the LPD method is useful for ARC fabrications of spherical silicon solar cells.     

Stereolithographic Fabrication and Microwave Properties of 1D Tunable Photonic Crystals Composed of YIG and Alumina Plates in Resin

One-dimensional (1D) photonic crystals composed of a center polycrystalline yttrium iron garnet (YIG) plate sandwiched with alternate alumina and resin plates were fabricated using stereolithography. The formed crystals showed a transmission mode of microwave in band gap as a result of resonance at the YIG plate. The transmission frequency and intensity were controlled by applying an external magnetic field. These phenomena can be explained by Faraday and Voigt effects of YIG in magnetic field. The propagation characteristics of microwaves agreed well with the calculated results using the finite element method.     

Current–Voltage Characteristics of Cobalt-Doped Inversion Boundaries in Zinc Oxide Bicrystals

Undoped and cobalt-doped basal inversion boundaries were fabricated in ZnO bicrystals to investigate their current–voltage characteristics. High-resolution transmission electron microscopy observations and energy-dispersive X-ray spectroscopy analyses for a cobalt-doped bicrystal revealed that the boundary was highly coherent and free from intergranular phases and precipitates, but a certain amount of cobalt was present near the boundary. The cobalt-doped bicrystals exhibited nonlinear characteristics that depended on cooling rates from annealing temperature, in contrast to linear characteristics of the undoped bicrystals. It is suggested that the presence of cobalt impurities enhances the formation of acceptor-like native defects near the boundaries to generate electrostatic potential barriers.     

Proposal of Using Ozonated Water to Control Biofilm Formation on Mouth-Related Devices

The purpose of this study was to evaluate the antimicrobial effectiveness and dental applications of ozonated water generated by portable equipment (0.667 mg/L). Total elimination of C. albicans, E. coli and S. mutans planktonic cells was observed after 5 min. Reduction in the number of viable cells of biofilms formed on acrylic resin was observed for C. albicans, S. mutans and E. coli. The same effect was observed on biofilms of E. coli, S. aureus, S. mutans and C. albicans formed on stainless steel. Ozonated water was effective for the disinfection of experimentally contaminated toothbrushes.     

Added-mass estimation of flat membranes vibrating in still air

It is widely known that added mass has a significant influence on the natural frequency of membrane structures. Previously, the total added mass of a one-dimensional membrane has been investigated with theoretical analysis. However, no test result has been applied to verify results of the theoretical analysis. Furthermore, the distribution of the added mass is still unclear. In this study, first, thin-airfoil theory was applied to analyze the distribution of the added mass. The distribution of the added mass was found to be basically uniform for the first vibration mode of a one-dimensional membrane. Then, it was assumed that the added mass of one vibration region is independent of the added mass of another vibration region for higher vibration modes, where the vibration regions are the parts of the membrane separated by the nodal points (nodal lines for two-dimensional membranes) of the vibration mode. Based on the above analysis, a simplified added-mass model was proposed; i.e., for every vibration mode, the added mass of each vibration region is equivalent to the uniformly distributed air with a height of α_ml, where α_m is the added mass coefficient and l is the diameter of the inscribed circle of the corresponding vibration region. To ascertain the added-mass coefficient and verify the simplified added-mass model, a vacuum chamber was designed to test the vibration of a circular flat membrane in still air with varying air pressures. The results showed that the simplified added-mass model was accurate when the added-mass coefficient was taken as 0.65. The efficiency of the proposed simplified added-mass model was further verified by an existing test of a three-sided membrane.     

Thermal therapy and evaluation by a precise temperature control device

Moxibustion, one of the thermal therapies used in oriental medicine, has several problems, including the fact that temperature distribution over a treatment region is not uniform, the treatment temperature cannot be controlled, and smoke is emitted. To solve these problems, we developed a precise thermal heat transfer control device and applied it to clinical medicine as a substitute for conventional moxibustion. The abdominal heating controller developed in this study has an effect equal to that of moxibustion and can heat the treatment region of human skin uniformly. The treatment effect of the device was evaluated in a clinical experiment, in which we found that these devices can treat ileus, diarrhea, and related disorders. We sought the optimal temperature for thermal therapy with regard to gender, body mass index, and age. We carried out a numerical simulation of temperature distribution inside a human body when the abdominal region is heated. Temperature distribution of the heated abdominal region was calculated using a 2‐D axisymmetric model considering bioheat generation such as blood perfusion and metabolism. The calculation results confirmed that the thermal effect cannot reach the viscera. © 2011 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/htj.20334