Pharmacological and Pharmacokinetic Studies of Anti-diabetic Tropolonato-Zn(II) Complexes with Zn(S(2)O(2)) Coordination Mode

Zn(II) complexes are expected to be useful in the treatment of diabetes mellitus because of the hypoglycemic effect produced by its insulin-mimetic activity. Previous reports indicated that Zn(II) complexes with coordinating sulfur exhibit higher insulin-mimetic activity. In this study, we investigated the pharmacological and pharmacokinetic differences between Zn(O(4)) and Zn(S(2)O(2)) coordination modes of tropolonato-Zn(II) complexes with insulin-mimetic activity. Among the tropolonato-Zn(II) complexes with various coordination modes, di(2-mercaptotropolonato)zinc(II) (ZT2) with the Zn(S(2)O(2)) coordination mode was found to exhibit the highest in vitro insulin-mimetic activity with respect to inhibition of free fatty acid (FFA) release and enhancement of glucose uptake in isolated rat adipocytes treated with adrenaline. On comparing investigations of the antidiabetic effect in vivo, ZT2 was found to exhibit potent hypoglycemic activity and improve insulin resistance in type 2 diabetic KKA(y) mice at a low orally administered daily dose. Di(tropolonato)zinc(II) (ZT1), which has the Zn(O(4)) coordination mode, had a lesser effect at the same dose. In a pharmacokinetic analysis based on the (65)Zn tracer method, ZT2 was found to be absorbed at a significantly slower rate with a longer half-life than was ZT1. These results suggest that the potent hypoglycemic activity of ZT2 might be attributed to its long half-life.     

Influence of dissolved-air concentration on spatial distribution of bubbles for sonochemistry

The pulsation of ultrasonic cavitation bubbles at various dissolved-air concentration in a sonochemical reaction field of standing-wave type is investigated experimentally by laser-light scattering. When a thin light sheet, finer than half the wavelength of sound, is introduced into the cavitation bubbles at an antinode of sound pressure, the scattered light intensity oscillates. The peak-to-trough light intensity is correlated with the number of bubbles that contribute to the sonochemical reaction. It is shown that as the dissolved air concentration becomes higher, the weighted center of the spatial distribution of the peak-to-trough intensity tends to shift towards the liquid surface. At higher concentration of the dissolved air, a great deal of bubbles with size distribution generated due to coalescence between bubbles disturbs sound propagation to change the sound phase easily. A standing wave to trap tiny oscillating bubbles is established only at the side which is nearer to the liquid surface. Also at higher concentration, liquid flow induced by drag motion of bubbles by the action of radiation force becomes apparent and position-unstable region of bubble is enlarged from the side of sound source towards the liquid surface. Therefore, the position of oscillating bubbles active for sonochemical reaction is limited at the side which is nearer to the liquid surface at higher concentration of the dissolved air.     

Enhancement of sonochemical reaction rate by addition of micrometer-sized air bubbles

The sonochemical reaction rate has been enhanced by the introduction of tiny air bubbles. The bubbles including micrometer-sized ones are produced by method of atomization and are introduced into aqueous luminol solution under 141-kHz sonication in order to investigate the enhancement of sonochemical reaction rate by introduction of tiny bubbles through the intensity measurement of sonochemiluminescence (SCL). It is shown that the introduction of tiny bubbles under sonication accomplishes the large SCL intensity compared to the cases of sonication only and liquid flow under sonication. It is also shown that it is important to adjust the configuration of tiny-bubble addition to the sound field. Through the investigations on the intensity and the spatial pattern of luminol-SCL, it has been clarified that tiny bubbles added into the sonicated liquid not only cause the liquid flow but also increase the number of collapsing bubbles active for sonochemical reaction. It is also shown that the tiny-bubble addition enhances the reaction rate of KI oxidation under sonication. Therefore, the present method of introduction of tiny bubbles is effective for enhancement of sonochemical reaction rate.     

Fabrication of zinc ferrite nanocrystals by sonochemical emulsification and evaporation: observation of magnetization and its relaxation at low temperature

A new ultrasound assisted emulsion (consisting of rapeseed oil and aqueous solution of Zn(2+) and Fe(2+) acetates) and evaporation protocol has been developed for the synthesis of zinc ferrite (ZnFe(2)O(4)) nanoparticles with narrow size distribution. The as-synthesized sample consisted of crystalline zinc ferrite particles with an average diameter of approximately 4 nm, whereas the average size of the heat-treated ferrite particles increases to approximately 12 nm. To remove the small amount of oil present on the surface of the as-synthesized ferrite sample, heat treatment was carried out at 350 degrees C for 3 h. The as-synthesized and heat-treated ferrites were characterized by X-ray diffraction (XRD), infrared spectroscopy (IR), TGA/DTA, transmission electron microscopy (TEM), and energy dispersion X-ray spectroscopy (EDS) techniques. Magnetic measurements show that the nanocrystalline ZnFe(2)O(4), prepared through this technique, is either at par with those obtained in other cases or even more improved. Both the as-synthesized and heat-treated samples reveal relaxation of magnetization. Our study also shows that one can tailor the magnetization and relaxation pattern by suitably controlling the particle size of the nanocrystalline ZnFe(2)O(4). The key features of this method are avoiding (a) the cumbersome conditions that exist in the conventional methods, (b) the usage of necessary additive components (stabilizers or surfactants, precipitants), and (c) calcination requirements. In addition, rapeseed oil has replaced organic nonpolar solvents used in earlier studies. As a whole, this simple straightforward sonochemical approach results in a better pure phase system of nanoferrite with improved magnetic properties.     

Determination of the acid value of instant noodles: interlaboratory study

An interlaboratory study was performed to evaluate the method for determining the acid value of instant noodles, based on the Japanese Agricultural Standard (JAS), with extraction of lipid using petroleum ether at a volume of 100 mL to the test portion of 25 g. Thirteen laboratories participated and analyzed 5 test samples as blind duplicates. Statistical treatment revealed that the repeatability (RSDr) of acid value was <6.5%, and the reproducibility (RSDR) of acid value was <9.6%. The HorRat values (RSDR/predicted RSDR) were 1.2-1.8, where the RSDR and the predicted RSDR were obtained in terms of free fatty acids in the noodles per unit weight, using the equation [acid value = percent free fatty acids (as oleic) x 1.99] and the extracted lipid contents. This method was shown to have acceptable precision by the present study.     

Dirac returns: Non-Abelian statistics of vortices with Dirac fermions

Topological superconductors classified as type D admit zero-energy Majorana fermions inside vortex cores, and consequently the exchange statistics of vortices becomes non-Abelian, giving a promising example of non-Abelian anyons. On the other hand, types C and DIII admit zero-energy Dirac fermions inside vortex cores. It has been long believed that an essential condition for the realization of non-Abelian statistics is non-locality of Dirac fermions made of two Majorana fermions trapped inside two well-separated vortices as in the case of type D. Contrary to this conventional wisdom, however, we show that vortices with local Dirac fermions also obey non-Abelian statistics.