α-tocopherol affects the urinary and biliary excretion of 2,7,8-trimethyl-2(2′-carboxyethyl)-6-hydroxychroman, γ-tocopherol metabolite, in rats

In this study, we investigated a change in the excretory content of 2,7,8-trimethyl-2(2′-carboxyethyl)-6-hydroxychroman (γ-CEHC), a γ-tocopherol (γ-Toc) metabolite, in rat urine and bile by using a new high-performance liquid chromatography-elelectrochemical detection (HPLC-ECD) method. In this determination, CEHC [α- and γ-CEHC, where α-CEHC-2,5,7,8-tetramethyl-2(2′-carboxyethyl)-6-hydroxychioman] in the biological specimens were treated with 3 N methanolic HCl to hydrolyze conjugates and to promote esterification. The methylated samples were extracted by n-hexane/water (1∶2). The analyses of the methyl esters of α-CEHC and γ-CEHC were performed by an HPLC-ECD using an ODS-3 column at 35°C. The mobile phase was acetonitrile/water (45∶55, vol/vol) containing 50 mM sodium perchlorate. After rat urine and bile samples, respectively, were methylated as described above, methylated biliary metabolites were identified by liquid chromatography mass spectrometry as methyl esters of γ-CEHC. Furthermore, we examined the differences in the excretion of γ-CEHC between rat urine and bile after an oral administration of γ-Toc or α- +γ-Toc by the above HPLC method. In the γ-Toc group, each vitamin E-deficient rat was given 0.5 mL of a stripped corn oil preparation containing 10 mg of γ-Toc. In the α- +γ-Toc group, the rat was given 10 mg of α-Toc and 10 mg of γ-Toc. The content of γ-CEHC in rat urine from the α- +γ-Toc group was increased more in comparison to the γ-Toc group at 18–36 h after oral administration. Moreover, the content of γ-CEHC in rat bile in the α- +γ-Toc group was increased more in comparison to the γ-Toc group at 6–18 h after oral administration. Therefore, we have suggested that γ-CEHC was shifted mainly to urinary excretion after γ-CEHC had been excreted into the bile. Furthermore, we assume that α-Toc may affect the metabolism of γ-Toc to γ-CEHC in the body.     

Cyanation of N‐Acylhydrazones with Trimethylsilyl Cyanide Promoted by a Brønsted Base and a Lewis Acid

Cyanation of N‐acylhydrazones using trimethylsilyl cyanide (TMSCN) proceeded well in the presence of an amine to afford the corresponding α‐hydrazinonitriles in high yields. For less reactive substrates, the combined use of an amine and a catalytic amount of scandium triflate [Sc(OTf)₃] was effective to promote the reactions. The mechanistic study suggested that the amine worked as a Brønsted base.     

Effect of Heat Treatment in Air on the Surface of a Sintered Ba8Al16Si30-Based Clathrate

A polycrystalline silicon-based clathrate of nominal composition Ba₈Al₁₅Si₃₁ was prepared by a combination of arc melting and spark plasma sintering. Its thermal stability in air and the effect on the surface of heat treatment in air, which are of practical importance for use of the material at elevated temperatures, were examined for different temperatures (873 K, 973 K, and 1073 K) and heating times (0–480 h). Thermogravimetry and differential thermal analysis in air in the range 300–1523 K indicated that Ba₈Al₁₅Si₃₁ in the bulk form had relatively good thermal stability in air at high temperatures. X-ray diffraction measurements, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy revealed that a thin layer of oxide (probably a barium aluminate, BaAl₂O₄) was formed on the surface by heat treatment in air. The thickness of the oxide layer increased with increasing temperature and heating time. Growth of the oxide layer can be explained well in terms of a diffusion mechanism. The activation energy for oxidation was estimated to be approximately 201 kJ/mol, which is comparable with that for thermal oxidation of silicon. The chemical composition of the interior of the Ba₈Al₁₅Si₃₁ was found to be stable to heat treatment in air.     

Application of liquid chromatography-nuclear magnetic resonance spectroscopy for the identification of ethyldimethylpyrazine, a food flavouring agent

The application of liquid chromatography-nuclear magnetic resonance spectroscopy (LC-NMR) for the direct identification of ethyldimethylpyrazine, a food flavouring agent, has been studied. The commercial product is a mixture of two regio-isomers, 2-ethyl-3,5-dimethylpyrazine (1) and 2-ethyl-3,6-dimethylpyrazine (2); however, the exact composition of the mixture is unknown. Structural characterization by LC-MS and GC-MS was not possible because both regio-isomers yield the same molecular related ion and ion fragmentation. To rapidly identify the two regio-isomers, the product was analyzed by LC-NMR with on-flow and fraction loop modes. From the results, the structure elucidations of the two regio-isomers could be carried out without the need to isolate the isomers by the usual procedures.     

Recognition of speed limit signs in night scene images in Japan

A method to recognize speed limit signs in night scene images is proposed in this paper. The proposed method involves two main stages. First, sign candidates are detected by using the outline of white domain on the signs. This region has little influence on the change of color information or size. Next, the feature and common parts in speed limit signs are distinguished on the basis of their layout. We extract a suitable label from sign candidates and recognize it as a sign through a matching experiment. Experimental results for 596 images show that the proposed method is able to recognize speed limit signs with an accuracy of 94.3%. It is also shown that 423 images without speed limit signs are perfectly distinguished as images having no speed limit signs. © 2013 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

High-resolution inventory of Japanese anthropogenic mercury emissions

Heavy metals like mercury that are emitted into the environment remain there indefinitely, posing a long-term threat to both the environment and human health. Elemental mercury is volatile and is in gaseous form, and because of the long residence time, transported over long distances. Comprehensive control of mercury emissions therefore remains an important international issue. The crucial steps for designing effective approaches for such control include the quantification of mercury emissions by sources and the identification of geographical characteristics of the emissions. In this study a detailed, high-resolution inventory of Japanese mercury emissions in 2005 was developed to improve understanding of their geographical distribution. Proceeding from a national emissions inventory per source category, emissions were spatially allocated with increasing geographical resolution in a stepwise procedure using statistics from geographic information resources, yielding mercury emissions per prefecture, per municipality and per grid cell of approximately 1 × 1 km. The five prefectures with the highest emissions were Fukuoka, Yamaguchi, Hyogo, Oita, and Hokkaido, accounting for 35.2% of all emissions. In each prefecture a small number of municipalities account for a major share of emissions. Distribution by grid cell is characterized by a concentration of 50% of all emissions in a mere 32 of the 255?954 grid cells over which emissions are distributed in this study. It was also quantitatively confirmed that use of larger grid cells leads to greater uncertainty in emissions distribution. Problems with data collection are clarified and measures to improve the accuracy of future estimation are proposed.     

Enhanced piezoelectric properties of barium titanate–potassium niobate nano-structured ceramics by MPB engineering

Barium titanate (BaTiO₃, BT)–potassium niobate (KNbO₃, KN) (BT–KN) nanocomplex ceramics with various KN/BT molar ratios were prepared by the solvothermal method. From a transmittance electron microscopy (TEM) observation, it was confirmed that KN layer thickness of the BT–KN nanocomplex ceramics was controlled from 0 to 44 nm by controlling KN/BT molar ratios. Their dielectric constants were measured at room temperature and 1 MHz, and a maximum dielectric constant of around 400 was measured for the BT–KN nanocomplex ceramics with a KN thickness of 22 nm. TEM observation revealed that below KN thickness of 22 nm, BT/KN heteroepitaxial interface was assigned to the strained interface while over 22 nm, the interface was assigned to the relaxed one. These results suggested that the strained heteroepitaxial interface could be responsible for the enhanced dielectric constants.     

Caspase inhibitors increase the rate of recovery of neural stem/progenitor cells from post-mortem rat brains stored at room temperature

To match the demand of regenerative medicine for nerve system, collection of stem cells from the post-mortem body is one of the most practical ways. In this study, the storage condition of the post-mortem body was examined. We prepared neural stem/progenitor cells (NSPCs) from post-mortem rat brains stored at different temperatures. When brains were stored at 4 °C, for one week, we were able to obtain neurospheres (a spheroid body containing NSPCs) by stimulation of cells with epidermal growth factor (EGF). Incremental increases in storage temperature decreased the rate of appearance of neurospheres. Within 48 h at 15 °C, 24 h at 25 °C, in both condition, we were able to recover NSPCs from post-mortem rat brains. At 15 °C, 90% of neurosphere-forming activity was lost within 24 h. However, even after 24 h at 25 °C, 2% neurosphere-forming activity remained. After 6 h of death, there was very little difference between the rates of NSPC recovery at 4 °C and 25 °C. Addition of caspase inhibitors to both the rat brain storage solution and the NSPC culture medium increased the rate of neurosphere-forming activity. In particular, an inhibitor of caspase-8 activity increased the NSPC recovery rate approximately three-fold, with no accompanying detrimental effects on neural differentiation in vitro.     

Biodiscrimination of α-tocopherol stereoisomers during intestinal absorption

Synthetic α-tocopherol (α-Toc) contains equal amounts of eight different stereoisomers, and the four stereoisomers with the 2R configuration are generally more active than their correspoding 2S-isomers. We investigated the biodiscrimination of α-Toc stereoisomers during intestinal absorptionin situ andin vitro. Intestinal absorption of α-Toc stereoisomers was examinedin situ in vitamin E-deficient rats with cannulated thoracic ducts. We found that the ratios of α-Toc stereoisomers in lymph of the all-rac-α-Toc group were the same as the administered α-Toc stereoisomers, and 2R-isomers occupied approximately 50% of absorbed α-Toc. The uptake of α-Toc stereoisomers also was measured using Caco-2 cells cultured on filter membranes. The concentration ofRRR-α-Toc in Caco-2 cells was not significnatly different from that ofSRR-α-Toc. Therefore, the discrimination of α-Toc stereoisomers does not occur during absorption in small intestine, suggesting the liver as a source for the biodiscrimination.     

Study of the surface morphology of platinum thin films on powdery substrates prepared by the barrel sputtering system

The transition of Pt from a nanoparticle to a film on SiO₂ particles modified by the sputtering system with barrel-type powder sample holder (the barrel sputtering system). X-ray diffraction (XRD) and scanning electron microscopy (SEM) measurements reveal that the Pt nanoparticles grow in size with an increase in the duration of sputter deposition. The morphology of Pt changes from highly dispersed nanoparticles to a worm-like structure followed by a continuous Pt film, depending on the amount of Pt modified. Transmission electron microscopy (TEM) measurements reveal that the thin Pt film in the worm-like structure has a uniform thickness of approximately 2.6 nm, indicating film growth in a two-dimensional mode followed by an island mode.