Studies on heterogeneous degradation of polypropylene/talc composite: Effect of iron impurity on the degradation behavior

In this study, an effect of iron oxide (Fe₂O₃) impurity in talc on degradation behavior of polypropylene (PP)/talc composite was studied using a PP/Fe₂O₃ model composite sample. The thermal oxidative degradation was performed at 100°C. Although the degradation of a pure PP sample hardly occurred at such temperature, the existence of Fe₂O₃ induced the PP degradation. The degraded PP part was formed around the Fe₂O₃ grain in the PP/Fe₂O₃ sample. It was found from the optical microscope observation that the degraded PP was able to diffuse only within the PP amorphous part. The analysis of the oxidation distribution on the degraded PP surface was performed employing a scanning electron microscope/electron dispersive spectrometer. The result showed that the PP spots in the vicinity of the Fe₂O₃ grain were unoxidized during the initial degradation process, and the oxidized PP spots were located at around 6 μm distance from the Fe₂O₃ grain. It was concluded that the degradation was initiated microscopically away from the Fe₂O₃ grain so that the Fe₂O₃ had both the abilities to accelerate the decomposition of PP hydroperoxide compounds and to reduce the produced radical species into nonradical products. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Intrahepatic cholangiocarcinoma with marked hypervascularity

Anomalous continuation of the inferior vena cava with an azygous vein is a rare vacular anomaly. The enlarged venous system may simulate adenopathies or mediastinal and retroperitoneal masses on the radiographs. We describe the case of a patient with lung cancer - a pathological condition which may cause adenopathies at these sites - and a dilated azygous-hemiazygous system resulting from failure of formation of the hepatic segment of the inferior vena cava.     

Preparation and characterization of Ni–PTFE plate as an electrode for alkaline fuel cell: Effects of conducting materials on the performance of electrode

Polytetrafluoroethylene (PTFE) fine particles (25 μm) were coated with 29–43 wt% Ni using electroless Ni plating. The Ni-plated PTFE (Ni–PTFE) particle conductivity increased concomitantly with increasing Ni contents. For 43 wt% Ni particles, the conductivity was about 300 S m⁻¹. After pressing the particles into plates with 300 kg cm⁻² pressure and subsequent heat treatment at 350 °C, acetylene black (AB) and graphite particles were introduced into the plates as conducting materials to elucidate effects on electrical conductivity and gas permeability. Plates containing AB (1.3 wt%) and graphite (5 wt%) respectively showed 1.25 and 1.5 times higher conductivity than the original Ni–PTFE plate did. The AB particles particularly caused pore volume expansion at the 0.1–1.0 μm size range in Ni–PTFE plates. The expanded total pore volume (0.159 cm³ g⁻¹) of Ni–PTFE plate with AB particles improved gas permeability, which increased the electrode life performance (25% up for 24 h) in alkaline fuel cells (AFCs). The current density of Ni–PTFE electrode containing AB particles was about 4.5 times than that of original Ni–PTFE electrode.     

A precision digital instantaneous heart rate meter with a wide range

A precision digital instantaneous heart rate meter with a wide range of 0-1023 beats/min was developed for converting the time interval between two successive heart beats to frequency. The resolution of this device is 1 beat/min, and the maximum nonlinearity error is less than 0.06 percent relative to full scale. Therefore, this device has two advantages, i.e., it is more precise and it has a wider range than other conventional tachometers.     

Metal island films for write-once multiwavelength three-dimensionaloptical disks

Metal island films are proposed and investigated as optical data storage media for write-once multiwavelength three-dimensional disks. The basic operation has been experimentally confirmed using aluminium-silver compound metal island films for 490 nm and silver-gold compound metal island films for 810 nm. Compact write-once multiwavelength three-dimensional disks for durable long-term data storage could be realised by using metal island films with high reflectance near the resonance wavelength, and large reflectance change by heating     

An electromagnetic transient simulation model of grid‐connected inverters for dynamic voltage analysis of distribution systems

Transient analysis is an indispensable tool for analyzing the voltage fluctuation of distribution systems according to the penetration of distributed generations with grid‐connected inverters. Electromagnetic transient (EMT) analysis is suitable for the purpose because it enables detailed modeling of the inverters and accurate simulation of their dynamic behavior. However, the EMT analysis requires a smaller calculation time step by a factor of 500 if the simulated power system includes the inverters. Simulation of the inverters is a bottleneck in speeding up the EMT analysis. This paper proposes a novel average‐value modeling method for the grid‐connected inverters. The proposed inverter model operates in a larger calculation time step, and speeds up the EMT analysis of distribution systems containing the inverters. The maximum error in the output power was 8% compared to the result by the conventional model. Dynamic voltage simulations are demonstrated with a test case, which includes tap changing transformers with a voltage controller and a photovoltaic generation facility. The proposed model reduces the required calculation time by a factor of 754 compared to the conventional model whereas there is no significant difference in the simulated result.     

Modulation of apolipoprotein E-mediated plasma clearance and cell uptake of emulsion particles by cholesteryl ester

Cholesteryl ester, along with triglyceride (TG), is the major core component of plasma lipoproteins. We investigated the effect of core composition on the physical state and metabolic behavior of lipid emulsions, as model particles of lipoproteins. Fluorescence studies using 1,6-diphenylhexatriene analogs showed that although cholesteryl oleate (CO) significantly decreased core mobility, the surface rigidity of phosphatidylcholine (PC) monolayers was independent of core composition. When intravenously injected into rats, the increased amount of core CO tended to retard TG emulsion removal from plasma, and the initial clearance rate was correlated with the amount of apolipoprotein E (apoE) bound from plasma. In addition, PC liposomes with a similar emulsion particle size showed negligible binding of apoE and were cleared at a slower rate compared to all emulsions. Furthermore, the effect of CO on the binding behavior of apoE to the emulsion surface and the emulsion uptake by hepatocytes was assessed in vitro. Replacing core TG with CO was found to decrease the apoE binding capacity to emulsions markedly without changing the binding affinity and thereby to reduce the cell uptake of emulsion particles by HepG2 cells. These results indicate that the physical state of core lipids, which can be modulated by cO content, plays a role in emulsion metabolism through the alteration in apoE binding.     

Vitellogenesis-related ovary cathepsin D from Xenopus laevis: purification and properties in comparison with liver cathepsin D

Cathepsin D was purified from ovaries of Xenopus laevis by both QAE-cellulose and pepstatin-Sepharose chromatography and then characterized and compared with Xenopus liver cathepsin D. Ovary cathepsin D appeared predominantly as a 43-kilodalton (kDa) molecular mass, as revealed by SDS-polyacrylamide gel electrophoresis, whereas the liver enzyme was obtained exclusively as a 36-kDa protein. The purified 43-kDa ovary enzyme cleaved vitellogenin limitedly to produce yolk proteins at pH 5.6. The specific activity of ovary cathepsin D was five to six times lower than that of the liver enzyme, as measured by hemoglobin-hydrolysis at pH 3, but the ovary enzyme was shown to be superior to the liver enzyme in terms of vitellogenin-cleaving activity, as examined at pH 5.6. Ovarian enzyme preparations contained variable amounts of 36-kDa species; this form was considered to be an autolytic product of the 43-kDa form arising during purification, because it was not detected in oocyte extracts but was generated by incubation of the purified 43-kDa enzyme alone in an acid solution. The conversion of the 43-kDa form by hepatic factors was accompanied by a marked increase in hemoglobin-hydrolytic activity.     

Spout eyes formed by an emerging gas plume at the surface of a slag-covered metal melt

This article deals with the spout eyes developing, at the surface of a metal melt, in the ladle during argon stirring. Cold model experiments involving a mercury bath with an oil layer as slag and industrial experiments on a 350 t steel ladle have been carried out. The eye geometry as measured with a video technique is highly dynamic. The time average of the free surface area and the time fraction of complete coverage have been determined and are represented with dimensionless correlations.