Ameloblast-lineage cells of rat tooth germs proliferate and scatter in response to hepatocyte growth factor in culture

Hepatocyte growth factor (HGF) is considered to be one of the mediators of epithelial-mesenchymal interactions during early organogenesis and to be involved in the development of murine molars. In this study, the immunohistochemical localization of HGF and of its receptor, c-Met, revealed that HGF was distributed in the proliferating mesenchymal cells in the dental papillae and that c-Met was continuously expressed in the epithelial cells during the development of rat incisors. These observations confirmed the involvement of HGF in the development of rat incisors, as demonstrated previously in molars. We then used a primary culture of ameloblast-lineage cells, prepared from mandibular incisors of young rats, to examine the direct effects of HGF on the growth and differentiation of ameloblasts. We found that HGF at 2-20 ng/ml induced a marked increase in the number of ameloblast-lineage cells and in the scattering of such cells. Our results suggest that HGF promotes the proliferation and scattering of ameloblast-lineage cells simultaneously.     

Effects of intensity of incident light and concentrations of Synechococcus sp. and 2-hydroxy-1,4-naphthoquinone on the current output of photosynthetic electrochemical cell

We examined the effects of the intensity of incident light and the concentrations of cyanobacterium, Synechococcus sp. UTEX2380, and an electron transfer mediator, 2-hydroxy-1,4-naphthoquinone (HNQ), on the current output of a photosynthetic electrochemical cell operated under illumination. Though the current density was higher with increasing concentration of Synechococcus sp., increase in the current density was suppressed at more than 24 μg chlorophyll/ml. The current density reached a maximum value at 1 mM HNQ. The current density was saturated at 50 W/m² probably due to reoxidation of HNQ by oxygen photosynthetically evolved. The conversion efficiency of light energy to electrical energy was 3.3%. For the analysis of energy loss for four steps in the electrochemical cell reaction, the energy loss remarkably arose from the reaction of the electron transfer chain and the high internal resistance of the electrochemical cell.     

Study on presence/absence of central nervous tissues as BSE specified risk material in processed and raw meat products in Japan

Various countries including Japan issued the complete removal of brain and spinal cord (SC) tissues from meat products due to BSE risk factor. In this study using commercially available Ridascreen^® risk material test kit, we tried to evaluate the efficiency of removing specific risk material (SRM) from meat products. Brain and SC tissues were added to grind meats in different concentrations and respective absorption values were obtained using Ridascreen^® test kit. The kit detected both brain and SC at 0.1%, below its claimed sensitivity level, for brain and SC combined. Thus, using this commercial test kit, we tested cross-section of samples sold in Obihiro area, Japan. In the test standard controls 0, 0.2%, 1% and 2% were practiced. All most all the tested samples absorption values near to standard 0, and it is concluded that all the samples that we tested were absence or at a very minimal levels of SRM.     

Carbon recycle nuclear hydrogen carrier system for transportation field

Possibility of a carbon recycle hydrogen carrier system driven by nuclear power for transportation field was discussed. The hydrogen carrier system, which was zero carbon dioxide emission and small hydrogen compression work and explosion risk, was examined for fuel cell vehicles. The combination of the hydrogen carrier system with a high-temperature gas reactor was proposed. It was expected that the carrier system realized lower pressure and safe storage of hydrogen consisting with the similar energy efficiency of conventional water electrolysis hydrogen system. Carbon neutral bio-mass energy system and the carrier system were compared for the next generation vehicle energy system. Bio-mass energy had the limitation of quantity and would take small part of vehicle market in Japan. Nuclear assisted bio-mass hydrogen system could enhance yield of bio-fuels under carbon neutral. The carbon recycle nuclear hydrogen carrier system was expected to be applicable to the demand of much more larger number of vehicles because it was free from the limitation of bio-mass carbon quantity.     

Prediction of coiling conditions of plate in coilbox by controlled FEM simulation

A method using the finite element simulation for predicting coiling conditions of intermediate plates in a coilbox installed between roughing and finishing stands of hot strip rolling is proposed. In the coilbox, the intermediate plate is coiled to prevent the drop in temperature due to the radiation from the surface of the plate in the waiting period. In the present method, non-steady-state deformation of the plate in the coilbox is simulated by the finite element method, and the rolls are appropriately moved in accordance with the simulated results to form the plate in a coil. Since the formation of the coil is influenced by the bending shape near the front end of the plate, the deformation behaviour near the front end is monitored in the finite element simulation, and the positions of the rolls for coiling the plate are determined from instantaneous movement of the rolls once without trial and error. In addition, the coiling is stabilised by controlling the rotation of the roll. The predicted coiling conditions are applicable to actual coilbox machines.     

Solubilities of NiO and LaNiO3 in Li/Na eutectic carbonate with rare-earth oxide

For the commercial application of molten carbonate fuel cells (MCFCs) under high-pressure operation, the problem of Ni shorting should be solved that is closely related to the solubility of cathode material. In order to improve the MCFC cathode stability, effects of the addition of rare-earth metal oxides to the molten carbonates have been quantitatively investigated. Especially, La₂O₃ addition to the molten carbonate significantly decreased the solubility of NiO. Such low solubility of NiO was caused by effects of both the acid-base equilibrium of molten carbonate and the activity of Ni in solid by the formation of complex oxide. Solubilities of LaNiO₃ and Nd₂NiO₄ were also smaller than that of NiO in molten carbonate as the same reason as that of NiO in the molten carbonates with saturated La₂O₃. Based on the data of solubility, a new parameter was proposed to evaluate the solubility of metal ion in molten carbonates. This parameter concerned with the acid-base equilibrium of melts and the activity of solid for the metal oxide. A linear relationship with the measured solubility of metal oxide in molten carbonates was obtained by this parameter. It would be indicated that the parameter is useful for the prediction of metal oxide solubilities in molten carbonates.     

Luminescent Properties of Sintered Spherical Silica With Alkali Metal Oxide Additives

The correlation of luminescent properties to the polymorphism in sintered amorphous spherical silica with alkali metal additives has been investigated. The luminescent properties and the crystalline phases changed with the different kinds of alkali metal additives, and the firing temperature. The blue luminescence at 470 nm was observed for all amorphous sintered silica containing Na₂O, K₂O, Rb₂O or Cs₂O, while the yellowish green luminscence at 545 nm was for some crystalline sintered silica. The blue luminescence was assumed to be related to defects produced by dehydration of silanol groups and the yellowish green ones in crystalline and liquid phases.     

An investigation of band profile around the grain boundary of Cu(InGa)Se2 solar cell material by scanning probe microscopy

We performed scanning tunneling spectroscopy on an as‐grown Cu(InGa)Se₂ (CIGS) thin film and photo‐assisted Kelvin probe force microscopy on a CIGS solar cell. From these measurements, we estimated the band profile around the grain boundaries (GBs). The results indicate both downward bending of the conduction band edge and broadening of the band gap near GBs. We can therefore conclude that photo‐generated electrons and holes are easily separated by the built‐in field near GBs, and consequently their recombination at the GBs should be suppressed. Copyright © 2011 John Wiley & Sons, Ltd.     

Copper as a Collaborative Partner of Zinc-Induced Neurotoxicity in the Pathogenesis of Vascular Dementia

Copper is an essential trace element and possesses critical roles in various brain functions. A considerable amount of copper accumulates in the synapse and is secreted in neuronal firings in a manner similar to zinc. Synaptic copper and zinc modulate neuronal transmission and contribute to information processing. It has been established that excess zinc secreted during transient global ischemia plays central roles in ischemia-induced neuronal death and the pathogenesis of vascular dementia. We found that a low concentration of copper exacerbates zinc-induced neurotoxicity, and we have demonstrated the involvement of the endoplasmic reticulum (ER) stress pathway, the stress-activated protein kinases/c-Jun amino-terminal kinases (SAPK/JNK) signaling pathway, and copper-induced reactive oxygen species (ROS) production. On the basis of our results and other studies, we discuss the collaborative roles of copper in zinc-induced neurotoxicity in the synapse and the contribution of copper to the pathogenesis of vascular dementia.     

Partially oxidized niobium carbonitride as a non-platinum catalyst for the reduction of oxygen in acidic medium

Partially oxidized NbC_0.5N_0.5 has been evaluated as a non-platinum catalyst for the reduction of oxygen in acidic medium. NbC_0.5N_0.5 powder was partially oxidized in N₂ gas containing O₂ of 10⁻⁴ atm at the temperature range of 700-1000 °C. Partially oxidized NbC_0.5N_0.5 had a definite oxygen reduction reaction (ORR) activity, while as-prepared NbC_0.5N_0.5 and completely oxidized Nb₂O₅ had a poor catalytic activity for ORR. The onset potential of the partially oxidized NbC_0.5N_0.5 for the ORR achieved 0.92 V vs. RHE in 0.1 M H₂SO₄ at 30 °C. The results of X-ray absorption spectroscopy and ionization potential measurements suggested that oxygen-vacancy defects might be responsible for the oxygen reduction capability by creating electronically favorable oxygen adsorption sites.