Dill seed extract improves abnormalities in lipid metabolism through peroxisome proliferator‐activated receptor‐α (PPAR‐α) activation in diabetic obese mice

Dill, a small annual herb, is widely used as a flavoring agent in dishes including salads. It has been demonstrated that dill extract and its essential oil show hypolipidemic effects in rats. However, the mechanism of these effects has not been elucidated yet. We found that dill seed extract (DSE) activated peroxisome proliferator‐activated receptor‐α (PPAR‐α), an indispensable regulator for hepatic lipid metabolism, by luciferase assay. Thus, we performed DSE feeding experiments using diabetic obese model KK‐Ay mice to examine the effects of DSE on PPAR‐α activation in vivo. A 4‐week feeding of DSE contained in a high‐fat diet decreased plasma triacylglyceride and glucose levels and increased the mRNA expression levels of fatty acid oxidation‐related genes in the liver. In addition, the DSE feeding as well as bezafibrate (a PPAR‐α potent agonist) feeding increased oxygen consumption rate and rectal temperature. These results indicate that DSE suppresses high‐fat diet‐induced hyperlipidemia through hepatic PPAR‐α activation.     

High-strength silicon nitride ceramics obtained by grain-boundary crystallization

A monolithic type of toughened silicon nitride ceramics has been developed from Si₃N₄-Y₂O₃ systems. However, because of the existence of a second phase, the fracture strength decreases at elevated temperatures. To improve the high-temperature strength of silicon nitride, some additional components were investigated. It was found that the addition of hafnia to the Si₃N₄-Y₂O₃-AIN system gave a greater high-temperature strength based on the promotion of grain-boundary phase crystallization: namely, 126 kg mm⁻² in 3-point bend strength at 1300 °C for the hot-pressed specimen, and 90 kg mm⁻² at 1300 °C for the pressureless sintered specimen. The role of the hafnia in crystallization is not yet clear, and is being characterized by electron microscopy and microanalysis.     

Applications of methacryloyl isocyanate for coatings

The heterofunctionality of methacryloyl isocyanate (MAI) monomer allows several routes for its use. A number of vinyl-functionalized monomers have been made by reaction of MAI with active hydrogen compounds. As an example, the vinyl-functionalized silicone monomer was applied to coating films and was found to be capable of controlling the wettability and oxygen permeability of the film. When MAI was homopolymerized or copolymerized with acrylic or styrenic monomers, the reactivity of the pendant acyl isocyanates remained fairly high. Thus urethane-type crosslinkings were provided by pendant acyl isocyanates in polymers under milder conditions than in the comparable isocyanate system. MAI reacts with hydroxy group-containing resins. These may then be further utilized as graft sites or for crosslinldng with polyamine, either by radical initiation or by irradiation. The MAI adduct of epoxy resins has been evaluated.     

Quantitative analysis of detailed lignin monomer composition by pyrolysis-gas chromatography combined with preliminary acetylation of the samples

Detailed quantitative analysis of lignin monomer composition comprising p-coumaryl, coniferyl, and sinapyl alcohol and p-coumaraldehyde, coniferaldehyde, and sinapaldehyde in plant has not been studied from every point mainly because of artifact formation during the lignin isolation procedure, partial loss of the lignin components inherent in the chemical degradative methods, and difficulty in the explanation of the complex spectra generally observed for the lignin components. Here we propose a new method to quantify lignin monomer composition in detail by pyrolysis-gas chromatography (Py-GC) using acetylated lignin samples. The lignin acetylation procedure would contribute to prevent secondary formation of cinnamaldehydes from the corresponding alcohol forms during pyrolysis, which are otherwise unavoidable in conventional Py-GC process to some extent. On the basis of the characteristic peaks on the pyrograms of the acetylated sample, lignin monomer compositions in various dehydrogenative polymers (DHP) as lignin model compounds were determined, taking even minor components such as cinnamaldehydes into consideration. The observed compositions by Py-GC were in good agreement with the supplied lignin monomer contents on DHP synthesis. The new Py-GC method combined with sample preacetylation allowed us an accurate quantitative analysis of detailed lignin monomer composition using a microgram order of extractive-free plant samples.     

Considerations on filtration mechanism in pretreatment process of sea water desalination by reverse osmosis

In order to make sufficiently clear the meaning of the MFT or FI, analytical investigation was made during extensive research and development of sea water desalination with a pilot plant. After measuring the MFT and FI, the matter on the filters was analysed by X-ray fluorescence and electron prove micro analyses (EPMA), and observed by scanning electron microscopy (SEM). On the basis of these results, this paper briefly discusses the filtration mechanism and evaluates the analytical methods for understanding the suspended matter which affects the quality of sea water.     

Preparation of nanocomposite for optical application using ZnTe nanoparticles and a zero-birefringence polymer

Surface-modified ZnTe nanoparticles were mixed in a zero-birefringence polymer matrix. Transmission electron microscopy images revealed that aggregates of ZnTe nanoparticles with a diameter of ∼20 nm were uniformly dispersed in the polymer. The transmittance of ZnTe nanocomposites rapidly decreased at wavelengths shorter than the critical wavelength corresponding to the band gap of ZnTe nanoparticles, an effect which became significant as the volume fraction of particles increased. In this way, the optical characteristic of ZnTe nanoparticles was added to the polymer. The intrinsic zero-birefringence was confirmed in the heat-drawn ZnTe nanocomposites. As the ZnTe nanocomposites were left in air, a lowering of transmittance was observed. This was due to the oxidation of Zn and the resultant deposition of Te in the ZnTe nanocomposite, as the light absorption of Te is significant. The formation of oxygen non-permeable SiO₂ films onto the ZnTe nanocomposite by the sol-gel method was useful in preventing oxidation so that the decrement of transmittance decreased from 47.2% to 14.9% at 530 nm near the ZnTe band gap.     

Determination of the degree of acetylation of chitin/chitosan by pyrolysis-gas chromatography in the presence of oxalic Acid

A new method to determine directly and rapidly the degree of acetylation of chitin/chitosan was developed based on reactive pyrolysis-gas chromatography in the presence of an oxalic acid aqueous solution. The degree of acetylation was precisely evaluated on the basis of peak intensities of the characteristic products such as acetonitrile, acetic acid, and acetamide originating from the N-acetyl group of N-acetyl-d-glucosamine units of chitin/chitosan. The observed values were in good agreement with those obtained by (1)H NMR and the other methods. Moreover, the proposed technique was applicable to any kinds of chitin/chitosan samples over the whole range of acetylation including insoluble chitin/chitosan and perfectly acetylated artificial chitin having higher crystallinity to which (1)H NMR had been inapplicable.     

Synthesis of Silicon Nitride Powder from Silica Reduction

Silicon nitride powder synthesis was investigated via the silica reduction method. Adding Si₃N₄ to the SiO₂-C mixture increased the reaction rate and promoted the formation of homogeneous Si₃N₄ grains. This effect could be explained on the basis that each Si₃N₄ particle acts as a 'seed' for the reaction.     

Pretreatment of seawater RO feed by means of coagulation – filtration

The effect of pH of the filtrate on the head loss in the inline coagulation-filtration for the pretreatment of reverse osmosis seawater desalination was investigated. The experiment was carried out using a double media filter with aluminum sulfate as a coagulant. It was found that the filtration characteristics were dependent on the pH of the filtrate. The rate of elevation in the head loss and the amount of suspended particles in the filtrate decreased with an increase in the pH, over the range of experimental conditions. The results were briefly considered in relation to the deposit morphology of suspended particles on the surface of the filter grain.     

Effect of the physical properties of gas on the volume of bubble formed from a submerged single orifice

The effects of the gas properties on the volume of a bubble formed from a submerged single orifice in the presence of pressure fluctuations in the gas chamber are investigated experimentally. The bubble volumes are affected by the specific heat ratio of gas and/or the gas density depending on the dimensionless capacitance number N_c. An extended two stage bubble formation model is proposed by considering the physical properties of gas. The bubble volumes calculated by the present model compare reasonably well with the experimental results.