Thermoelectric Behavior of Sb- and Al-Doped <Emphasis Type="Italic">n</Emphasis>-Type Mg<Subscript>2</Subscript>Si Device Under Large Temperature Differences

The thermoelectric (TE) characteristics of Sb- and Al-doped n-type Mg₂Si elemental devices fabricated using material produced from molten commercial doped polycrystalline Mg₂Si were examined. The TE devices were prepared using a plasma-activated sintering (PAS) technique. To complete the devices, Ni electrodes were fabricated on each end of them during the sintering process. To realize durable devices for large temperature differences, thermodynamically stable Sb-doped Mg₂Si (Sb-Mg₂Si) was exposed to the higher temperature and Al-doped Mg₂Si (Al-Mg₂Si) was exposed to the cooler temperature. The devices consisted of segments of Sb-Mg₂Si and Al-Mg₂Si with sizes in the following ratios: Sb-Mg₂Si:Al-Mg₂Si = 4:1, 1:1, and 1:4. A device specimen composed solely of Sb-Mg₂Si showed no notable deterioration even after aging for 1000 h, while some segmented specimens, such as those with Sb-Mg₂Si:Al-Mg₂Si = 1:1 and 1:4, suffered from a considerable drop in output current over the large ΔT range. The observed power generated by specimens with Sb-Mg₂Si:Al-Mg₂Si = 1:1 and 1:4 and sizes of 2 mm × 2 mm × 10 mm were 50.7 mW and 49.5 mW, respectively, with higher and lower temperatures of 873 K and 373 K, respectively. For the sample composed solely of Sb-Mg₂Si, a power of 55 mW was demonstrated. An aging test for up to 1000 h for the same ΔT range indicated drops in output power of between ∼3% and 20%.     

Fabrication of textured B4C ceramics with oriented tubal pores by strong magnetic field-assisted colloidal processing

Highly structure-controlled B₄C ceramics were prepared via strong magnetic field-assisted slip casting of a slurry, containing B₄C base particles and pore-forming agents with a fiber shape. To achieve gas release at a lower porosity for maintaining its mechanical strength, these B₄C ceramics had a structure in which a large number of oriented tubal pores were dispersed in a crystallographically-aligned and dense B₄C matrix phase. The B₄C microstructure, such as structuration and orientation degree distributions of the B₄C grains and tubal pores, was characterized by SEM observation, EBSD analysis, and X-ray CT. Among the investigations, it was found that the oxidic impurities, as an inhibitor of sintering, which existed on the B₄C surface, can be removed by ethylation and azeotropy due to an ethanol treatment followed by vacuum drying. Thus, an ethanol treatment of a green compact before sintering was significantly effective for the fabrication of the B₄C ceramics, including the microstructure that coexisted with a dense matrix phase with tubal pores. The resultant ceramic specimens showed the remarkable three-point bending strength of 459?554 MPa, which is two times higher when compared to conventional B₄C pellets with a similar porosity.     

A Mannosylated,PEGylated Albumin as a Drug Delivery System for the Treatment of Cancer Stroma Cells

Mannose receptors that are expressed on macrophages and fibroblasts in cancer stroma are promising therapeutic targets for cancer treatment. Albumin can be used as a drug carrier in chemotherapeutics due to its accumulation in the tumor tissue by the enhanced permeability and retention effects. A mannosylated albumin was recently developed as a new drug carrier targeting cells that express mannose receptors such as macrophages and fibroblasts in cancer stroma. The mannosylated albumin is specifically distributed to hepatic macrophages in vivo, leading to an extremely short residence time in the blood. Here, a dual-modified albumin, i.e., mannosylated and polyethylene glycosylated (PEGylated) is reported, to improve its blood circulating time and stromal cell targeting. The product efficiently delivers paclitaxel to stromal cells in a mouse melanoma model, thus resulting in the disruption of stromal cells and suppressed tumor growth, which is seven times stronger than that for PEGylated albumin. The findings suggest that the dual-modified albumin has the potential to provide maximal therapeutic efficacies of chemotherapeutics for the treatment of intractable cancer.     

A ROCK Inhibitor Promotes Graft Survival during Transplantation of iPS-Cell-Derived Retinal Cells

Currently, retinal pigment epithelium (RPE) transplantation includes sheet and single-cell transplantation, the latter of which includes cell death and may be highly immunogenic, and there are some issues to be improved in single-cell transplantation. Y-27632 is an inhibitor of Rho-associated protein kinase (ROCK), the downstream kinase of Rho. We herein investigated the effect of Y-27632 in vitro on retinal pigment epithelium derived from induced pluripotent stem cells (iPS-RPE cells), and also its effects in vivo on the transplantation of iPS-RPE cell suspensions. As a result, the addition of Y-27632 in vitro showed suppression of apoptosis, promotion of cell adhesion, and higher proliferation and pigmentation of iPS-RPE cells. Y-27632 also increased the viability of the transplant without showing obvious retinal toxicity in human iPS-RPE transplantation into monkey subretinal space in vivo. Therefore, it is possible that ROCK inhibitors can improve the engraftment of iPS-RPE cell suspensions after transplantation.     

Dielectric microcalorimeter utilizing a quantum ferroelectric thermometer

A dielectric capacitance thermometer was fabricated using KTa_0.99Nb_0.01O₃ (KTN) quantum ferroelectrics. The electric capacitance of the KTN thermometer was measured as a function of temperature from 0.1 to 300?K using the four-terminal-pair method. The KTN thermometer exhibited a dependence of the electric capacitance on the temperature that showed promise for using the thermometer as a microcalorimeter. A prototype of the dielectric microcalorimeter (DMC) was assembled with the KTN thermometer and irradiated with alpha rays with an energy of 5.5 MeV at a temperature of 100 mK. When applying a DC bias voltage to the DMC, the detection signals could be observed at the output of the preamplifier. A response of the DMC to alpha rays was obtained despite the poor signal-to-noise ratio caused by long wirings for the detection signal readout inside the refrigerator.     

Experimental study on combustion characteristics of compost using New‐type combustor

The aim of the present study is to develop the biomass furnace combustor, which can effectively use the compost as a fuel. Here, the compost that is made from pig's waste and has the calorific value of 2000 kcal/kg is employed here. Emphasis is placed on the optimum conditions of fuel and air flow rates and moisture content of the compost and the corresponding combustion gas components and combustion gas temperature in the combustor. It is found from the study that (i) except 40% of the compost's moisture content, the self‐combustion of compost as the fuel takes place, (ii) the combustion gas concentrations are affected by gas temperature, and (iii) the optimum value of the air‐to‐fuel ratio is obtained based on the gas temperature and the concentration of combustion gases. Copyright © 2016 John Wiley & Sons, Ltd.     

Synthesis of Carbon Nanotubes on Fly Ashes by Chemical Vapor Deposition Processing

Fly ashes are the waste product following the combustion of coal. Disposal of fly ashes is a serious environmental problem; therefore, finding a new utilization of fly ashes is highly demanded. Carbon nano-structures have been widely studied as key materials in a wide range of applications, including sensing, saturable absorber, and so on, because of its optical and electromagnetic absorption property. Adding the property of carbon nanotubes (CNTs) to fly ashes expands applications of fly ashes. In this paper, we present the fabrication of multi-walled carbon nanotubes (MWCNTs) on fly ashes by thermal chemical vapor deposition (CVD) process, which result in simple, low-cost, large-amount production of MWCNTs. Copyright © 2009 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Equivalence in Harmonics Between Cycloconverters and Bridge Converters

The similarity between a six-pulse three-phase cycloconverter operating in the circulating current-free mode and a six-pulse three-phase bridge converter is discussed analytically with regard to the rms value and the harmonics of the respective output voltages. A method is presented for calculating the rms voltage of a family of sideband frequencies which are generated in the output voltage of the cycloconverter. The results obtained from the analysis help to predict the amplitudes of subharmonics and beat frequencies with the cycloconverter and are essential for the design of the output filters. Analytical results are verified by comparison with those of experiment and digital computer simulation.