Sterols,methylsterols, and triterpene alcohols in threeTheaceae and some other vegetable oils

The unsaponifiables from threeTheaceae (Camellia japonica L.,Camellia Sasanqua Thunb., andThea sinensis L.) oils and alfalfa, garden balsam, and spinach seed oils and shea fat were separated into four fractions: sterols, 4-methylsterols, triterpene alcohols, and less polar compounds by thin layer chromatography. While the sterol fraction was the major one for the unsaponifiables from alfalfa and spinach seed oils, the triterpene alcohol fraction was predominant for the unsaponifiables from all other oils. The sterol, 4-methylsterol, and triterpene alcohol fractions were analyzed by gas chromatography. All the sterol fractions were alike in their compositions, consisting exclusively of Δ⁷-sterols, such as α-spinasterol and Δ⁷-stigmastenol as predominant components together with Δ⁷-avenasterol and 24-methylcholest-7-enol. Obtusifoliol, gramisterol (occasionally accompanied with cycloeucalenol), and citrostadienol, together with several other unidentified components, were found in the 4-methylsterol fractions from all of the oils except shea fat. The 4-methylsterol fraction from shea fat showed a characteristic composition containing a large proportion of unidentified components which had relative retention time greater than that of citrostadienol, while no citrostadienol was detected. β-Amyrin, lupeol, and butyospermol were major components of the triterpene alcohol fractions from most of the oils, but the fraction from spinach seed oil contained cycloartenol and 24-methylene-cycloartanol as predominant components. There is a close similarity in the compositions of unsaponifiables (sterols, 4-methylsterols, and triterpene alcohols) of the threeTheaceae oils. Two sterols, α-spinasterol and Δ⁷-stigmastenol, and five triterpene alcohols were isolated from tea seed oil. Moreover, five unidentified components beside parkeol, butyrospermol, α-amyrin, and lupeol were isolated from the triterpene alcohol fraction of shea fat.     

Densification and Cell Performance of Gadolinium-Doped Ceria (GDC) Electrolyte/NiO–GDC Anode Laminates

A thin film (60 μm thick) of a gadolinium-doped ceria (GDC) electrolyte was prepared by the doctor blade method. This film was laminated with freeze-dried 42 vol% NiO–58 vol% GDC mixed powder and pressed uniaxially or isostatically under a pressure of 294 MPa. This laminate was cosintered at 1100 °–1500 °C in air for 4–12 h. The laminate warped because of the difference in the shrinkage of the electrolyte and electrode during the sintering. A higher shrinkage was measured for the electrode at 1100 °–1200 °C and for the electrolyte at 1300 °–1500 °C. The increase of the thickness of anode was effective in decreasing the warp and in increasing the density of the laminated composite. The maximum electric power density with a SrRuO₃ cathode using 3 vol% H₂O-containing H₂ fuel was 100 mW/cm² at 600 °C and 380 mW/cm² at 800 °C, respectively, for the anode-supported GDC electrolyte with 30 μm thickness.     

Nanogrinding of multi-layered thin film amorphous Si solar panels

Nanogrinding was performed on the cross-sections of amorphous Si thin film solar panels, which are nanoscale multi-layer structures consisting of hard and brittle materials. The deformed structures of the panel cross-sectional surfaces after grinding were investigated using electron and atomic force microscopy. The nanogrinding results were compared with those obtained from polishing and nanoscratching, demonstrating that the three processes had produced consistent surface characteristics. Though nanogrinding produced nanometric surface roughness with ductile material removal, but could cause cracking, edge chipping and delamination at thin film interfaces. The results of this work are of value for developing the efficient machining process for thin film solar panels and other brittle multi-layer materials.     

Nanostructure formation in the surface layer of metals under influence of high-power electric current pulse

The possibility to tailor the microstructure of metals is explored utilising a skin-effect for surface treatment. The theoretical simulation of the electric and magnetic fields in a metallic cylinder shows that melting followed by rapid quenching can occur in a skin layer of 5–10-μm thickness if the amplitude of a single electric pulse of several nanoseconds duration is of the order of hundreds kiloamperes. The experiments using the SUS304 stainless steel show that besides a thin amorphous layer, a specific nano-twin structure can form at the near-surface region. The appearance of nano-twins is explained considering the stress components arising at the surface layer and in the bulk of the specimen during shock wave propagation caused by temperature gradients and the Lorentz force. It is shown that the high stress amplitudes can arise locally, furnishing the required conditions for twin nucleation and resulting in intensive plastic deformation of the sub-surface layer.     

Development and evaluation of the interferometric monitor for greenhouse gases: a high-throughput fourier-transform infrared radiometer for nadir earth observation

The interferometric monitor for greenhouse gases (IMG) was the precursor of the high-resolution Fourier-transform infrared radiometer (FTIR) onboard a satellite for observation of the Earth. The IMG endured the stress of a rocket launch, demonstrating that the high-resolution, high-throughput spectrometer is indeed feasible for use onboard a satellite. The IMG adopted a newly developed lubricant-free magnetic suspension mechanism and a dynamic alignment system for the moving mirror with a maximum traveling distance of 10 cm. We present the instrumentation of the IMG, characteristics of the movable mirror drive system, and the evaluation results of sensor specifications during space operation.     

Expression, structure and chromosomal localization of the human cGMP-binding cGMP-specific phosphodiesterase PDE5A gene

1. Nicotinylalanine, an inhibitor of kynurenine metabolism, has been shown to elevate brain levels of endogenous kynurenic acid, an excitatory amino acid receptor antagonist. This study examined the potential of nicotinylalanine to influence excitotoxic damage to striatal NADPH diaphorase (NADPH-d) and gamma-aminobutyric acid (GABA)ergic neurones that are selectively lost in Huntington's disease. 2. A unilateral injection of the N-methyl-D-aspartate (NMDA) receptor agonist, quinolinic acid, into the rat striatum produced an 88% depletion of NADPH-d neurones. Intrastriatal infusion of quinolinic acid also produced a dose-dependent reduction in striatal GABA content. 3. Nicotinylalanine (2.3, 3.2, 4.6, 6.4 nmol 5 microl(-1), i.c.v.) administered with L-kynurenine (450 mg kg(-1)), a precursor of kynurenic acid, and probenecid (200 mg kg(-1)), an inhibitor of organic acid transport, 3 h before the injection of quinolinic acid (15 nmol) produced a dose-related attenuation of the quinolinic acid-induced loss of NADPH-d neurones. Nicotinylalanine (5.6 nmol 5 microl(-1)) in combination with L-kynurenine and probenecid also attenuated quinolinic acid-induced reductions in striatal GABA content. 4. Nicotinylalanine (4.6 nmol, i.c.v.), L-kynurenine alone or L-kynurenine administered with probenecid did not attenuate quinolinic acid-induced depletion of striatal NADPH-d neurones. However, combined administration of kynurenine and probenecid did prevent quinolinic acid-induced reductions in ipsilateral striatal GABA content. 5. Injection of nicotinylalanine, at doses (4.6 nmol and 5.6 nmol i.c.v.) which attenuated quinolinic acid-induced striatal neurotoxicity, when combined with L-kynurenine and probenecid produced increases in both whole brain and striatal kynurenic acid levels. Administration of L-kynurenine and probenecid without nicotinylalanine also elevated kynurenic acid, but to a lesser extent. 6. The results of this study demonstrate that nicotinylalanine has the potential to attenuate quinolinic acid-induced striatal neurotoxicity. It is suggested that nicotinylalanine exerts its effect by increasing levels of endogenous kynurenic acid in the brain. The results of this study suggest that agents which influence levels of endogenous excitatory amino acid antagonists such as kynurenic acid may be useful in preventing excitotoxic damage to neurones in the CNS.     

Giant room-temperature magnetoresistance in single-crystal Fe/MgO/Fe magnetic tunnel junctions

The tunnel magnetoresistance (TMR) effect in magnetic tunnel junctions (MTJs) is the key to developing magnetoresistive random-access-memory (MRAM), magnetic sensors and novel programmable logic devices. Conventional MTJs with an amorphous aluminium oxide tunnel barrier, which have been extensively studied for device applications, exhibit a magnetoresistance ratio up to 70% at room temperature. This low magnetoresistance seriously limits the feasibility of spintronics devices. Here, we report a giant MR ratio up to 180% at room temperature in single-crystal Fe/MgO/Fe MTJs. The origin of this enormous TMR effect is coherent spin-polarized tunnelling, where the symmetry of electron wave functions plays an important role. Moreover, we observed that their tunnel magnetoresistance oscillates as a function of tunnel barrier thickness, indicating that coherency of wave functions is conserved across the tunnel barrier. The coherent TMR effect is a key to making spintronic devices with novel quantum-mechanical functions, and to developing gigabit-scale MRAM.     

Deep-ultraviolet Raman microspectroscopy: characterization of wide-gap semiconductors

We have developed a high-throughput deep-ultraviolet (DUV) Raman microspectrometer with excitation from a continuous wave (cw) laser operated at 244 nm that enables us to characterize thin surface layers of wide-gap semiconductors. This spectrometer system consists of a filter spectrometer for the rejection of stray light and a high-dispersion spectrograph combined with a liquid nitrogen cooled charge-coupled device (CCD) detector and extends the low-frequency limit of the observable spectral range down to 170 cm(-1). In the microscope we use a Cassegrain reflective objective for the collection of the scattered light and an off-axis mirror for introduction of the excitation laser light. DUV Raman spectroscopy has been applied for studying wide-gap semiconductors including SiC and AlGaN epitaxial films and shallow implanted layers of these materials. Raman spectra of various crystals have also been measured for examining the performance of this system. Resonance enhancement of Raman bands has been observed for several semiconductors, and the results are discussed.     

Electron holographic 3-D nano-analysis of Au/TiO2 catalyst at interface

Three-dimensional (3-D) nanostructures of gold catalysts supported on TiO2 were analysed by electron holography and high-resolution electron microscopy. The contact angle of the gold particle on TiO2 tended to be >90 degrees in the case of gold particles with a size (height) of >4 nm and it tended to be <90 degrees for gold particles with a height of <2 nm. The change in morphology increases the perimeter at the Au/TiO2 interface as the particle size decreases. This change in 3-D structure should be attributed to a change in electronic structure at the interface. It was found that electron holography enabled 3-D analysis at the atomic level and was effective for analysing nanostructured particles.