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In the present study, the effect of fine water mist on extinguishment of a methane–air counterflow diffusion flame was investigated to understand the underlying physics of fire extinguishment of highly stretched diffusion flame by water mist. Twin-fluid atomizers were used to generate polydisperse water mist of which Sauter mean diameters were 10, 20, 40, and 60 μm. When water mist is not added, the critical stretch rate at extinguishment is 439 s −1 as compared to the theoretical value of 460 s −1 . For the case with water mist addition, when the stretch rate is small enough, almost all the water mist evaporates within the flame zone. On the other hand, for high stretch rate case, large mist droplets pass through the flame zone and can reach the stagnation plane. However, no oscillatory motion was found around the stagnation plane. Critical stretch rate at extinguishment decreases monotonously with the mass fraction of water mist independently of the mist diameter within the range of D 32 from 10 μm to 60 μm. On the other hand, with increase in the surface area parameter, the critical stretch rate at extinguishment decreases rapidly and becomes less sensitive at large surface area parameter, of which tendency is qualitatively in good agreement with theoretical predictions. For a constant surface area parameter, the critical stretch rate decreases with mist diameter because the mass fraction of water mist should increase in proportion to the mist diameter to keep the surface area parameter constant. When the water mist evaporates completely in the flame zone as in the present study, the mass fraction of the water mist is the dominant factor for fire extinguishment, rather than the surface area parameter. Therefore, an appropriate combination of stretch rate and water mist mass fraction should be provided to suppress effectively a given fire with a small amount of water mist. [ABSTRACT FROM AUTHOR]

Abstract: A microelectrode sensor mounted on a chip was investigated regarding its properties for detecting optical intensity. Comb-like shaped microelectrodes were constructed by a photolithographic method and consisted of a Cu film of 10μm thickness on a resin chip. Three comb-like electrodes with varying comb numbers were fabricated; lengths were: a =10mm (8 combs), a =5mm (4 combs), and a =2.5mm (2 combs). NaCl solutions of 1.0×10–4 to 1.0moll–1 (2–10μL) were applied on the microelectrode under white light irradiation of 0–1.5×103 lx emitted from an LED. Optical sensitivity was then evaluated by measuring the electrical resistance. The effects of electrode size and sensor material on the detection limits for optical sensitivity were investigated. The sensor responded to changes in light intensity when an electrolyte solution contacted the surface of a pair of comb-like electrodes. When a strong light was irradiated onto the microelectrode in contact with an NaCl solution, the electrical resistance markedly reduced. By contrast, when a weak light was irradiated on the microelectrode in contact with an NaCl solution, the electrical resistance increased. When the sensor size or the number of combs was increased, electrical resistance showed a marked decrease with increased light intensity. In particular, an eight-comb microsensor exhibited high responsiveness under weak light intensity within the range of 0–1.0×103 lx. When the electrolyte concentration is constant, electrical resistance also converges to a constant value. In all the various upper boards tested (polyimide, silicon rubber, glass, and PET film), the resistance value depended on the thickness regardless of the intensity of light irradiation. The various materials showed no effect on light intensity. However, the electrical resistance of the sensor increased for upper boards made of Teflon, polypropylene, and polychlorovinylidene for which electrical resistance was reduced when light intensity was high. It is suggested that polarization occurs when light is irradiated onto a metal sensor surface and the boundary surface of an electrolyte droplet. In the presence of a constant electrolyte concentration, the charge distribution on the surface of the sensor was found to change in accordance with the intensity of light irradiation. These results clearly demonstrate that photosensitivity and ion sensitivity, as well as the formation of the ion layer, are influenced by the choice of the cover material. We applied a microelectrode as an optical detector for a microarray to measure the concentration of a dye such as methylene blue. We measured the electrical resistance values, as well as those of light intensity, of four microelectrodes located on the reverse side of a microarray. Methylene blue solution was prepared at concentrations of 0, 1.0×10–3, 1.0×10–2, and 1.0×10–1 wt% and 50μL of each solution was applied to each of the microarrays. The upper board material was translucent and irradiated light could pass through the microarrays including the dye solution. The light that penetrated was received by each microelectrode, as well as a photosensor located under microarray. In each of the microarrays, the detection voltage of the microelectrode depended on the depth of the sample color. [Copyright &y& Elsevier]

ObjectiveWe previously found that ingested cocoa decreased visceral adipose tissue weight in rat. To elucidate the molecular mechanisms of that effect, we carried out experiments aimed at analyzing biochemical parameters and gene expression profiles.MethodsRats were fed either of two high-fat diets, differing only in supplementation with real or mimetic cocoa. On day 21, body weights, mesenteric white adipose tissue weights, and concentrations of serum triacylglycerol were measured. To investigate the molecular mechanisms underlying the effects of cocoa on lipid metabolism and triacylglycerol accumulation, we examined gene expression profiles in liver and mesenteric white adipose tissues using the GeneChip microarray system.ResultsFinal body weights and mesenteric white adipose tissue weights were significantly lower in rats fed the real cocoa diet than in those fed the mimetic cocoa diet (P < 0.05), and serum triacylglycerol concentrations tended to be lower in rats fed the real cocoa diet (P = 0.072). DNA microarray analysis showed that cocoa ingestion suppressed the expression of genes for enzymes involved in fatty acid synthesis in liver and white adipose tissues. In white adipose tissue, cocoa ingestion also decreased the expression of genes for fatty acid transport-relating molecules, whereas it upregulated the expression of genes for uncoupling protein-2 as a thermogenesis factor.ConclusionsIngested cocoa can prevent high-fat diet-induced obesity by modulating lipid metabolism, especially by decreasing fatty acid synthesis and transport systems, and enhancement of part of the thermogenesis mechanism in liver and white adipose tissue. [ABSTRACT FROM AUTHOR]

Capsiate is a capsaicin-like ingredient of a non-pungent cultivar of red pepper, CH-19 sweet. To elucidate the mechanisms underlying the non-pungency of capsiate, we investigated whether capsiate activates the cloned capsaicin receptor, TRPV1 (VR1). In patch-clamp experiments, capsiate was found to activate TRPV1 expressed transiently in HEK293 cells with a similar potency as capsaicin. Capsiate induced nociceptive responses in mice when injected subcutaneously into their hindpaws with a similar dose dependency as capsaicin. These data indicate that the non-pungent capsiate is an agonist for TRPV1 and could excite peripheral nociceptors. In contrast to this, capsiate did not induce any significant responses when applied to the skin surface, eye or oral cavity of mice, suggesting that capsiate requires direct access to nerve endings to exhibit its effects. Capsiate was proved to have high lipophilicity and to be easily broken down in normal aqueous conditions, leading to less accessibility to nociceptors. Another highly lipophilic capsaicin analogue, olvanil, was similar to capsiate in that it did not produce irritant responses when applied to the skin surface, although it could activate TRPV1. Taken together, high lipophilicity and instability might be critical determinants for pungency and so help in understanding the effects of capsaicin-related compounds. [Copyright &y& Elsevier]