80 GHz silicon diamond-heatsink Impatt diodes

80 GHz band silicon d.d.r. Impatt diodes with diamond heatsinks were fabricated. An output power of 1014 mW at 77.70 GHz was obtained by liquid-nitrogen-cooled operation, which gives the highest pf2 product, and 726 mW at 73.35 GHz by room temperature operation. Small-signal diode impedance was calculated considering operating temperature.     

ESCA study on the mechanism of adherence of metal to silica glass

Indium oxide films formed on the surface of silica glass samples by selective oxidation have been shown to greatly improve the adherence of gold-indium alloy to the silica glass. In order to clarify the role that the oxide films play in the reaction, thin indium films have been evaporated onto silica glass and heated at temperatures of between 973 and 1473 K, both in air and in hydrogen gas. Electron spectroscopy for chemical analysis (ESCA) measurements have then been made to investigate the chemical environments around oxygen and indium atoms at the reacting interface between the oxide and glass. Measured 01s and In3d _5/2 spectra reveal the formation of non-bridging oxygen atoms at the interface, in addition to the original bridging oxygen atoms in silica glass. Introduction of the non-bridging oxygen atoms and indium ions into the silica glass is concluded to be an essential factor in promoting good adherence between the gold alloy and silica glass.     

Effect of hypothermic anoxic cardioplegia on myocardial contractility

Dynamic brain scintigraphy was performed on seven patients with documented hydrocephalus of various aetiologies. The patients had a characteristic abnormality consisting of lateral displacement of the proximal middle cerebral activity associated with a paracentral lucent zone. No focal areas of increased activity were identified on the static brain images. A proposed mechanism for these findings is discussed.     

Optimal sulfur dioxide gas discharge control for Osaka city,Japan

This paper, using actual data, establishes a dynamical model of sulfur dioxide pollution and gives an optimal discharge control policy for Osaka city in Japan.From a mass balance of the gas, a linear scalar state equation is obtained. In spite of the simplicity of the model, it can represent the effect of wind speed, inversion layer, diffusion, boundary concentration and discharge intensity of the pollutant sources. Six unknown parameters in the model and system noise variance are identified by maximizing likelihood function by Flexible Polyhedron Search. This makes the model reasonably representative.A quadratic loss function for the control problem is the weighted sum of two terms; the loss caused by the discharge control and the loss due to the air pollution. The wind speed varies at random according to a Markov transition matrix, considering actual emergency control situations. The optimal control policy is obtained by Dynamic Programming, resulting in linear feedback control dependent on the wind speed, involving a Riccati equation. A practical method of the determination of the weighting coefficient in the loss function is proposed.Since the model is a scalar state system, the whole calculation can be performed with a relatively small computer. This ease of computation and the Markov property of the wind speed suggest that the proposed method is applicable to the actual emergency discharge control.     

Estimation of flooding in PEMFC gas diffusion layer by differential pressure measurement

The flooding, especially in gas diffusion layer (GDL), is one of the critical issues to put PEMFC to practical use. However, the experimental data of the flooding in GDL is so insufficient that the optimization design related to the water management for GDL has not established. In this study we developed a method to estimate the water saturation, namely the ratio of liquid water to pore volume in GDL. We fabricated a simple interdigitated cell where the supply gas is enforced to flow under rib. This structure enables to estimate the liquid water ratio in GDL by the measurement of differential pressure through the cell. We operated the cell and measured the differential pressure, and succeeded in estimating the water saturation, which changed largely with changing cell operation condition. In addition to this deferential pressure measurement, we measured the ionic resistance in polymer electrolyte membrane by ac impedance method. We evaluated and discussed the influence of the water saturation on cell voltage.     

Influence of morphology on photo‐degradation of low density polyethylene films

The effect of the morphology on photo‐degradation was investigated for low‐density polyethylene materials. For this purpose, films with different degrees of crystallinity and different degrees of orientation were prepared. For all the films, photodegradation was promoted at 336K for 12 days using a weather meter. The following results were obtained. There existed an induction period before degradation or chain scission. The induction period was longer for stretched films than for un‐stretched ones. Also, the rate of degradation became lower for stretched films. However, both the induction period and the rate of degradation hardly changed with heat‐treatment condition, that is, the degree of crystallinity. In the induction period, the density changed in a complicated manner. This complicated change must be due to the change in the molecular aggregation state of the amorphous phase. The rheological and GPC measurements indicated that photo‐degradation causes the lowering of molecular weight and the increase in higher molecular weight fraction, and consequently the broadening of molecular weight distribution. The lowering of molecular weight may be caused by chain scission and the increase in higher molecular weight fraction by the formation of crosslinks.     

Chemical stability enhancement and cytotoxicity reduction of papain loaded in PLGA nanospheres

Poly(lactic-co-glycolic acid) (PLGA) nanospheres loaded with papain were prepared by the emulsion solvent diffusion in water (ESD) and the w/o/w emulsion solvent evaporation (ESE) methods. The nanosphere loaded with papain from the ESE method gave smaller particle sizes (220–232?nm) and higher encapsulation efficiency of about two-folds than those from the ESD method. The morphology of the nanospheres loaded with papain prepared by the ESE method exhibited spherical shape and smooth surface investigated by SEM and TEM. The release profile of papain from the PLGA nanospheres of the ESD and ESE method indicated two phases with an initial rapid phase of 6?h and followed by the slow release phase of 48?h. The unloaded PLGA nanospheres from the two methods did not show any cytotoxicity in human skin fibroblasts, while the unloaded papain gave toxicity more than the loaded papain of 1.5 times. Papain loaded in PLGA nanospheres prepared by the ESE method was more chemical stable than the unloaded papain of eight and three times when kept at 4°C and 25°C for 6 weeks, respectively. The developed stable and low cytotoxic nanosphere loaded with papain can be further developed as topical products.     

Flavonoid Nobiletin Attenuates Cyclophosphamide-Induced Cystitis in Mice through Mechanisms That Involve Inhibition of IL-1β Induced Connexin 43 Upregulation and Gap Junction Communication in Urothelial Cells

Bladder inflammatory diseases cause various urinary symptoms, such as urinary frequency and painful urination, that impair quality of life. In this study, we used a mouse model of cyclophosphamide (CYP)-induced bladder inflammation and immortalized human urothelial (TRT-HU1) cells to explore the preventive potential of nobiletin (NOB), a polymethoxylated flavone enriched in citrus fruit peel, and investigate its mechanism of action in the bladder. Prophylaxis with PMF90 (60% NOB) attenuated the development of bladder inflammation and urinary symptoms in CYP-treated mice. PMF90 also reduced the upregulation of connexin 43 (Cx43), a major component of gap junction channels, in the bladder mucosa of CYP-treated mice. Stimulation of TRT-HU1 cells with the pro-inflammatory cytokine IL-1β increased Cx43 mRNA and protein expression and enhanced gap junction coupling—responses that were prevented by pre-treatment with NOB. In urothelium-specific Cx43 knockout (uCx43KO) mice, macroscopic signs of bladder inflammation and changes in voiding behavior induced by CYP treatment were significantly attenuated when compared to controls. These findings indicate the participation of urothelial Cx43 in the development of bladder inflammation and urinary symptoms in CYP-treated mice and provide pre-clinical evidence for the preventive potential of NOB through its anti-inflammatory effects on IL-1β signaling and urothelial Cx43 expression.     

Epitaxial growth of silver on an Si(111) 7×7 surface at room temperature

The growth of silver deposited onto an Si(111) 7 × 7 surface at room temperature was studied by reflection high energy electron diffraction. The reflections of thin silver layers appear at a deposition thickness of 1 monolayer with a high background, and they develop into successive streaks with increasing thickness. The reciprocal lattice of silver is composed of concentric coaxial cylinders. The silver layers have the [111] texture structure in which they have preferentially the epitaxial orientation $\text{[01}\text{1}\text{]}{}_{\mathrm{<mtext>Ag</mtext>}}\text{//[01}\text{1}\text{]}{}_{\mathrm{<mtext>Si</mtext>}}\text{on (111)}{}_{\mathrm{<mtext>Ag</mtext>}}\text{//(111)}{}_{\mathrm{<mtext>Si</mtext>}}$. The grain size of the layers is about ten atomic distances in diameter. Each layer grows continouusly in thickness to give the stacking order of the f.c.c. structure. The growth mode for room temperature condensation is considered to be a special case of the Frank-van der Merwe growth mode.