Abnormal metabolism of polyunsaturated fatty acids and phospholipids in diabetic glomeruli

Studies were done on changes in phospholipid content and fatty acid composition of phospholipids and on the role of the acylation pathway in synthesis of phospholipids in the development of abnormal fatty acid composition in the glomeruli of rats 2 and 10 mo after induction of diabetes with streptozotocin. The proportions of individual phospholipids in the glomeruli of rats were not changed 2 mo after induction of diabetes, but the proportion of phosphatidylethanolamine (PE) decreased and that of sphingomyelin increased 10 mo after induction of diabetes. In contrast, in liver the proportion of PE was increased and that of phosphatidylcholine was decreased. These results showed that changes of individual phospholipids in glomeruli were time-dependent and tissue-specific. Two mo after induction of diabetes, the main change in the phospholipid fatty acid composition of diabetic glomeruli was a decrease in arachidonic acid (AA); the main change in serum free fatty acids (FFA) was an increase in linoleic acid (LA) and a decrease in AA. Ten mo after induction of diabetes, the main changes in the phospholipid fatty acid composition of glomeruli were an increase in LA and a decrease in AA; the main change of the serum FFA composition was a decrease in AA. Thus, the fatty acid composition of glomerular phospholipids was not directly correlated to that of the serum in diabetic rats. Acyl-CoA synthetase and acyltransferase activities increased in diabetic glomeruli with either AA or LA as substrate, but activity toward LA increased more at 2 mo after induction of diabetes. Acyl-CoA synthetase activity increased in diabetic glomeruli with LA as substrate, but that did not change with AA as substrate at 10 mo after induction of diabetes. Furthermore, acyltransferase activity decreased in diabetic glomeruli with AA as substrate, although that did not change with LA as substrate at 10 mo after induction of diabetes.     

Retardation of volatile aldehyde formation in the exhaust of frying oil by heating under low oxygen atmospheres

Volatile aldehydes were generated in the exhaust of high-oleic safflower oil during heating at 180°C by spraying water into atmospheres with four levels of oxygen concentrations (2, 4, 10, and 20%). These aldehydes were quantitatively analyzed by HPLC after the conversion to 2,4-dinitrophenyl hydrazones. Ten alkanals (C₂ through C₁₀), eight 2-alkenals (C₃ through C₁₀) and three 2,4-alkadienals (C₇, C₉, and C₁₀) were found. These aldehyde levels were found to be positively correlated with both the heating time and the atmospheric oxygen concentration. The total amounts of aldehydes were the lowest in the oil heated in an atmosphere with 2% O₂, and corresponded to 1/10 of those in the atmosphere with 20% O₂. Acrolein was not found in oils heated in the atmosphere with 2% oxygen. These results suggest that frying in atmospheres with low oxygen levels can effectively decrease the generation of volatile aldehydes in the exhaust.     

Hydrothermal Formation of Hydroxyapatite Layers on the Surface of Type-A Zeolite

Type-A zeolite evenly covered with hydroxyapatite thin layers was prepared using hydrothermal treatment at 120°C for 8 h under autogenous pressure. The hydroxyapatite needlelike nanocrystals, 100–200 nm in diameter and 30 nm in thickness, were grown under the reaction between discharged Ca²⁺ ions from type-A zeolite and PO₄³⁻ ions in (NH₄)₃PO₄ solution. The preferential orientations of the c -axis of hydroxyapatite crystals perpendicular to a zeolite surface were observed using transmission electron microscopy. The crystal structure of type-A zeolite was not destroyed under the reaction, but the surface morphology was changed only with complete covering of scaly hydroxyapatite particles.     

Antioxidant effects of chlorophyll and pheophytin on the autoxidation of oils in the dark. II. The mechanism of antioxidative action of chlorophyll

To understand the mechanism of the antioxidant effect of chlorophyll on the autoxidation of oils in the dark, antioxidant activities of several derivatives of chlorophyll were compared. Antioxidant activities were observed in chlorophyll derivatives such as protopor-phyrin methyl ester and its magnesium chelated compound. Porphyrin seems to be an essential chemical structure for the antioxidant activity of chlorophyll. Chlorophyll did not decompose the hydroperoxides, but reduced free radicals such as 1,1-diphenyl-2-picrylhydrazyl. Electron spin resonance spectrum of the π-cation radical was recorded during the oxidation of chlorophyll in methyl linoleate solution. These observations suggest that chlorophyll may act as a hydrogen donor to break the chain reaction.     

Monte Carlo simulation of the sol-gel process for the hydrolysis and polycondensation of tin tetra-n-butoxide

The sol-gel process for the hydrolysis and polycondensation of tin tetra-n-butoxide in butanol was followed by viscosity measurements. The precipitation of tin-containing ultrafine particles was observed without any variation in the solution viscosity in the absence of diethylene glycols, while the viscosity increase was made without any precipitation by the addition of diethylene glycol. The induction period and the rate of the viscosity increase after the induction period was independent of the diethylene glycol content but depended upon the water content. The Monte Carlo simulation data were consistent with data for the viscosity experiment. The simulation was based on a kinetic model of the slow hydrolysis of tin tetra-n-butoxide, the reverse reaction of hydrolysis, and the polycondensation of the hydroxy derivatives.     

Relation between crystal structure and lattice oxygen content of sintered reaction-bonded silicon nitride

When reaction-bonded silicon nitride containing MgO/Y₂O₃ additives is sintered at three different temperatures to form sintered reaction-bonded silicon nitride (SRBSN), the thermal conductivity increases with sintering temperature. The β-Si₃N₄ (silicon nitride) crystals of SRBSN ceramics were synthesized and characterized to investigate the relation between the crystal structure and the lattice oxygen content. The hot-gas extraction measurement result and the crystal structure obtained using Rietveld analysis suggested that the unit cell size of the β-Si₃N₄ crystal increases with the decrease in the lattice oxygen content. This result is reasonable considering that the lattice oxygen with the smaller covalent radius substitutes nitrogen with the larger one in the β-Si₃N₄ crystals. The lattice oxygen content decreased with increasing sintering temperature which also correlated with increase in thermal conductivity. Moreover, it is noteworthy from the viewpoint that it may be possible to apply the lattice constant analysis for the nondestructive and simple measurement of the lattice oxygen content that deteriorates the thermal conductivity of the β-Si₃N₄ ceramics.     

Probability of precision micro-machining of insulating Si3N4 ceramics by EDM

Electrical discharge machining (EDM) is used as a precision machining method for the electrically conductive hard materials with a soft electrode material. But recently we succeeded to machine on insulating material by EDM. The technology is named as an assisting electrode method. The EDMed surface is covered with the electrical conductive layer during discharge. The layer holds the electrical conductivity during discharge. For micro-EDM, the wear of tool electrode becomes lager ratio than the normal machining. So the micro-machining is extremely difficult to get the precision sample.

In this paper to obtain a fine and precise ceramics sample, some trials were carried out considering the EDM conditions, tool electrodes material and assisting electrode materials. Insulating Si₃N₄ ceramics were used for workpiece. The machining properties were estimated by the removal rate and tool wear ratio. To confirm the change of micro-machining process, the discharge waveforms were observed. The micro-machining of the Ø0.05 mm hole could be machined with the commercial sinking electrical discharge machine.     

Carbon felt-based bioelectrocatalytic flow-through detectors: Highly sensitive amperometric determination of H2O2 based on a direct electrochemistry of covalently modified horseradish peroxidase using cyanuric chloride as a linking agent

Horseradish peroxidase (HRP) was chemically modified using cyanuric chloride (CC) as a linking agent onto a carbon felt (CF), which is a microelectrode ensemble of micro carbon fiber (>7 μm, diameter) with a random three-dimensional structure. The resulting HRP-modified CF (HRP-ccCF) exhibited well-defined redox waves based on the HRP heme Fe^III/Fe^II redox couple at −0.23 V vs. Ag/AgCl (at pH 7.0), while the HRP-adsorbed CF (HRP-CF) showed no apparent redox couple in the same potential range, indicating that the chemical modification of HRP via CC facilitated the direct electron transfer (DET) between HRP and CF. The apparent heterogeneous electron transfer rate constant k_s was estimated to be 35 s⁻¹. Cyclic voltammetry and electrochemical impedance spectroscopy revealed that the interfacial properties (i.e., structure, morphology of enzyme-layer) of covalently modified HRP (HRP-ccCF) and physically adsorbed HRP (HRP-CF) are different, resulting in the difference in the electron transfer properties. The HRP-ccCF was successfully used as a working electrode unit in bioelectrocatalytic flow-through detector for highly sensitive amperometric determination of H₂O₂. Under the optimized conditions (i.e., applied potential, 0 V vs. Ag/AgCl; carrier flow rate, 3.25 ml/min; and carrier pH 7.0), the cathodic peak current of H₂O₂ linearly increased up to 3 μM (sensitivity, 1.94 μA/μM; the detection limit, 0.08 μM [S/N = 3]) with sample through-put of ca. 90 samples/h.     

An empirical anisotropy correction model for estimating land surface albedo for radiation budget studies

Land surface albedo is one of the key parameters in the radiation budget, the hydrological cycle and climate modeling studies. It is now widely understood that large errors may occur in the estimation of surface albedo without taking into consideration the anisotropy reflectance effect, which is a general feature of the earth surface. Two major anisotropic correction methods exist for the retrieval of land surface albedo under clear sky conditions. One method involves linearly converting from top of the atmosphere (TOA) albedo to surface albedo, and another is based on the inversion of the Bidirectional Reflectance Distribution Function (BRDF) model of the surface. In the present study, a new approach that utilizes an empirical model for estimating surface albedo has been proposed for snow free land surfaces under clear sky conditions. We analyzed the bidirectional reflectance data set with numerous samples representing various land cover types, which derived from POLDER/ADEOS-1 multi-angle imagery data and distributed by MEDIAS-France. Through the analysis, an empirical relation between bidirectional reflectance and albedo was established and has been discussed in detail. The proposed model can be used for direct estimation of surface albedo from a single BRF observation when the sun-target-sensor geometry is known. No BRDF model inversion scheme is necessary. The present model has no or weak dependence on the existing land surface classifications, and is insensitive to wavelength. The theoretical absolute accuracy of the estimated albedo is approximately 0.010 for visible (0.4-0.7 μm), 0.023 for near infrared (0.7-3.0 μm) and 0.016 for shortwave (0.2-3.0 μm), respectively. Albedo consistency with viewing geometry has been verified, resulting in good agreement for albedo estimated from various viewing directions. Validation of the satellite estimated albedo derived by the proposed method, using field observations were also presented and results show it can give reasonably accurate estimation. The proposed method is expected to be a suitable candidate for practical applications of albedo estimation for sensors that do not perform multi-angle observations.     

The motion capturing of female divers under water and the trial production of motion viewers for developing a virtual diving experience learning system

The virtual diving experience learning system of “Ama”, Japanese traditional female divers, has been developed to simulate how divers move in a virtual space using the diving interface and utilizing an accelerometer and a gyroscope. This interface not only detects the diving motion but also outputs the movement. Diving motion is shown in the ways of hand motion while standing. Although this makes it possible for a learner to understand the divers’ actions more clearly, this system’s difficulty is in visualizing a divers’ actions including their hands or bodies. Therefore, our study focuses on developing the operation system to reproduce actual ways of Amas’ diving with a virtual human body in a virtual space. First, the motion capture was done in an underwater condition. In the next process, the virtual human body was created. Finally, with the motion viewer, the more vivid actions of the Ama were successfully reproduced much more than in previous attempts. Using this system, the effectiveness of the Amas’ movement learning was confirmed, because a learner practices Amas’ movement.