Interfacial region of poly(n-butyl acrylate)/silicon oxide

Poly(n-butyl acrylate) (PnBA) and silica nanoparticle composites were cast from toluene solutions and investigated via differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FT-IR), and X-ray diffraction (XRD) analysis. The results suggested that the composites contained amorphous bulk and interfacial regions. The mobility of side chains at the interfaces between PnBA and the silica nanoparticles differed from the mobility of side chains in bulk PnBA. FT-IR analysis showed that the difference in mobility was due to interactions between the carbonyl groups in PnBA and the silica surfaces. These results indicated that PnBA main chains near interfaces with silicon oxide were separated by a smaller distance than main chains in the bulk polymer.     

Stereoisomeric identification of norephedrine derived from methamphetamine or amphetamine: urinalysis results of 33 methamphetamine abusers and 1 amphetamine abuser in Japan

Stereoisomeric identification of norephedrine (NE) derived from methamphetamine (MA) or amphetamine (AM) was investigated by SIM-GC/MS assay using the urine of 33 MA abusers and 1 AM abuser. The assay simultaneously identified TFA-derivatized MA and AM metabolites, including AM, p-hydroxyl-MA (p-HMA), and p-hydroxyl-AM (p-HAM). The analysis lasted approximately 43 min, with a signal-to-noise ratio of >or=3 and a detection limit of 50 ng/mL. Among 12 urine samples from different subjects, only the S (+) form of MA and its metabolites (AM, p-HMA, p-HAM) was detected, however, a (1R,2S)-(-)-NE stereoisomer was also identified. Among the urine samples of two subjects, only the R (-) form of MA and its metabolites (AM, p-HMA, p-HAM) was detected, while NE was not detected. Following urinalysis of urine obtained from 19 MA abusers and 1 AM abuser, only the (1R,2S)-(-)-NE stereoisomer was identified, while unmetabolized MA, AM, and their metabolites (p-HMA, p-HAM), showed stereoselective metabolism. Although (1R,2S)-(-)-ephedrine (EP) alone was found in the urine of 1 (S)-(+)-MA user and 1 (S)-(+)- and (R)-(-)-MA user among 33 MA users, it was not present in the urine of the remaining 31 subjects. Therefore, (1R,2S)-(-)-NE was likely not of (1R,2S)-(-)-EP origin and was most likely from (S)-(+)-AM of the MA metabolite. The production ratio of (1R,2S)-(-)-NE to (S)-(+)-AM ranged from 0.01 to 0.25 in MA abusers and was 0.12 in AM abusers.     

High-yields heterologous production of the novel Aspergillus fumigatus elastase inhibitor AFUEI in Aspergillus oryzae

AFUEI, an elastase inhibitor produced by Aspergillus fumigatus strongly inhibits the elastolytic activity of A. fumigatus etc. To purify AFUEI, we constructed a strain that overproduces AFUEI by introducing the gene encoding AFUEI (Genbank accession no. AB546725) under control of the amyB promoter into the heterologous host Aspergillus oryzae. A. oryzae TF-4 displayed strong elastase inhibitory activity and produced considerably more AFUEI than that of A. fumigatus. Furthermore, AFUEI could be purified using culture broth and single ultrafiltration (UF) treatment, allowing for the effective production of AFUEI for use in clinical trials.     

Edible mushroom (Flammulina velutipes) extract inhibits melanosis in Kuruma shrimp (Marsupenaeus japonicus)

This study compared the potential of an aqueous extract of an edible mushroom (Flammulina velutipes) to prevent melanosis in cultured Kuruma shrimp (Marsupenaeus japonicus) with other antimelanosic compounds in vivo. The mushroom extract contained 9.1 mg/mL ergothioneine (ESH). Immersion of live full-grown shrimp in a 0.5% w/v solution of mushroom extract significantly reduced PPO activity in shrimp hemolymph. In addition, expression of the prophenoloxidase (proPO) gene decreased in hemocytes, suggesting that the extract blocked the activation of the proPO cascade. Consequently, the development of melanosis in the treated shrimp was significantly suppressed during ice storage. Treatment with a 0.05% w/v solution of sodium ascorbate and 4-hexyl-1,3-benzenediol had the same effect. In vitro experiments showed that ESH effectively inhibited PPO activity and activation of the proPO cascade in hemocyte lysate supernatant. This study suggests that in vivo application of F. velutipes mushroom extract is an effective natural alternative to synthetic antimelanosic agents to inhibit postmortem melanosis in shrimp. Practical Application: The extract of an edible mushroom (F. velutipes) containing ergothioneine can be a promising natural alternative to synthetic antimelanosic agents used to prevent postharvest melanosis in shrimp and other crustaceans. Furthermore, utilization of the mushroom trimmings could also help address the growing concerns on the disposal of such agricultural wastes and instead use it into a novel purpose as a source of antimelanosic and antioxidants for food and industrial application.     

Image field distribution model of wavefront aberration and models of distortion and field curvature

The distribution model of wavefront aberrations, which takes on a significant role in the designs and alignments of imaging optical systems without vignetting, is newly presented. This model decomposes the complicated distributions into the characteristic components, which clarifies the alignment criteria. For the actual alignments, only small displacements (decentering, tilt, and surface distance) of rotationally symmetric surfaces in the system are assumed. Then, the model, which regards the aberration distributions of the system as the sum of the contributions of each surface, is extended for the system with surface displacements. As a result of the derivation, it is concluded that the aberration distributions in the rotationally nonsymmetric systems can be expressed as the sum of several folds of rotationally symmetric components. In addition, it is presented that, based on this model, suitable distribution models, even of the arbitrary higher order, can be constructed for any aberration coefficients in various optical systems.     

Numerical Study for Hysteresis Phenomena of Shock Wave Reflection in Overexpanded Axisymmetric Supersonic Jet

When the high-pressure gas is exhausted to the vacuum chamber from the supersonic nozzle,the overexpandedsupersonic jet is formed at specific condition.In two-dimensional supersonic jet,furthermore,it is known that thehysteresis phenomena for the reflection type of shock wave in the flow field is occurred under the quasi-steadyflow and for instance,the transitional pressure ratio between the regular reflection(RR)and Mach reflection(MR) is affected by this phenomenon.Many papers have described the hysteresis phenomena for underexpandedsupersonic jet,but this phenomenon under the overexpanded axisymmetric jet has not been detailed in the pastpapers.The purpose of this study is to clear the hysteresis phenomena for the reflection type of shock wave at theoverexpanded axisymmetric jet using the TVD method and to discuss the characteristic of hysteresis phenomena.     

Direct water balance analysis on a polymer electrolyte fuel cell (PEFC): Effects of hydrophobic treatment and micro-porous layer addition to the gas diffusion layer of a PEFC on its performance during a simulated start-up operation

Effects of hydrophobic treatment and micro-porous layer (MPL) addition to a gas diffusion layer (GDL) in a polymer electrolyte fuel cell (PEFC) have been investigated from water balance analysis at the electrode (catalyst layer), GDL and flow channel in the cathode after a simulated start-up operation. The water balance is directly analyzed by measuring the weight of the adherent water wiped away from each the component. As a result, we find that hydrophobic treatment without MPL leads to the increase in liquid water accumulation at the electrode which limits the oxygen transport to the catalyst and then lowers the cell voltage rapidly during start-up, whereas the treatment decreases the water at the GDL. The water accumulation at the electrode also decreases the cumulative current that represents the power generation and calorific power indispensable for warming up at a temperature below freezing point. On the other hand, we directly find that the hydrophobic treatment with MPL addition suppresses the water accumulation at the electrode, which increases the cumulative current. In addition, it is found that increase in air permeability of a GDL substrate by its coarser structure increases the cumulative current, which is explained by enhancing the exhaust of the product water vapor and liquid as well as by enhancing the oxygen transport directly. Thus, the hydrophobic treatment with MPL addition and larger air permeability of a GDL substrate improve the start-up performance of a PEFC.     

Enhancement of pool boiling heat transfer in water and ethanol/water mixtures (effect of surface‐active agent)

The surface tension of alcohol/water mixtures has been measured over the whole fraction range and then it has been measured when a surface‐active agent was added into the mixtures. The effect of the concentration of alcohol and the surface‐ active agent on surface tension was experimentally clarified, in order to gain base data related to enhancement of the heat transfer coefficient in the mixtures and water. The experiment was also carried out to enhance the boiling heat transfer coefficients of water and alcohol/water mixtures on a horizontal heated fine wire at a pressure of 0.1 MPa by adding a surface‐active agent into the tested liquid. The results show, the coefficients were enhanced in lower alcohol concentration (C ≦ 0.5) and low heat flux range which occur just after the onset of boiling. It was also found that the enhancement effect by the surfactant disappears in concentrations over 1000 ppm. Finally, we demonstrated that the surface tension remarkably affects the heat transfer coefficients in nucleate pool boiling. © 2004 Wiley Periodicals, Inc. Heat Trans Asian Res, 33(4): 229–244, 2004; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20010     

Pool boiling heat transfer in binary mixtures of ammonia/water

Nucleate boiling heat transfer coefficients were measured during pool boiling of the mixtures of ammonia/water on a horizontal heated wire. The experiment was carried out at pressures of 0.4 and 0.7 MPa, at heat fluxes below 2000 kW/m² and over all ranges of fraction. The heat transfer coefficients in the mixtures are markedly less than those in single component substances and, in particular, are dramatically deteriorated in the vicinity of both single component substances. An applicability of existing correlations to the present experimental data is discussed. As a result, it is difficult for any existing correlation to predict the coefficients over all ranges of fraction.In the mixtures of ammonia/water, heat of dilution and of dissolution are generated near a vapor-liquid interface, while vapor with a richer concentration of ammonia is condensed and then diffused into a bulk liquid; while in most other mixtures, little heat is generated during any dilution and dissolution. The effect of the heat of dilution and of dissolution on pressure and temperature in a system (pressure vessel) is shown.