Influence of metal ion concentration in the glycol mediated synthesis of Gd2O3:Eu nanophosphor

The solvothermal synthesis of highly luminescent and homogeneous Gd₂O₃:Eu³⁺ nanophosphor using diethylene glycol as medium, followed by controlled combustion with citric acid as fuel is reported. The influence of concentrations of carboxylic acid and metal cations on the structure, morphology and luminescence properties are investigated in detail. The microscopic investigations indicate the nanocrystalline nature and the strong influence of cation concentration on the size, shape and agglomeration of the particles. It is found that increase in concentration of metal cations lead to the reduction in agglomeration of nanophosphors. The large value of intensity parameter Ω_2, suggested that Eu³⁺ ions reside in a more asymmetric environment, resulted in intense emission due to ⁵D₀–⁷F₂ electric dipole transition. Emission decay analysis of the samples exhibited one exponential nature. The samples prepared under optimum conditions showed a quantum efficiency of 78.63% and a moderately high life time of 1.217 ms.     

Supramolecular Architectures of Nucleic Acid/Peptide Hybrids

Supramolecular architectures that are built artificially from biomolecules, such as nucleic acids or peptides, with structural hierarchical orders ranging from the molecular to nano-scales have attracted increased attention in molecular science research fields. The engineering of nanostructures with such biomolecule-based supramolecular architectures could offer an opportunity for the development of biocompatible supramolecular (nano)materials. In this review, we highlighted a variety of supramolecular architectures that were assembled from both nucleic acids and peptides through the non-covalent interactions between them or the covalently conjugated molecular hybrids between them.     

Specification of individual variation in luminous efficiency for brightness

Principal component analysis was applied to spectral luminous efficiencies determined by the heterochromatic brightness matching by 51 and 70 observers for the field size. 2° and 10°, respectively, which were used to derive the CIE V_b,2(Λ) and V_b,10(Λ). Four principal components were found to explain the individual variation. the two deviation indices were introduced by slightly modifying the first and second principal scores and they were effectively used to specify individual variations and to predict the spectral luminous efficiency curve. Equations were derived to predict these two deviation indices as functions of luminous efficiencies at two wavelengths, 460 and 640 nm in the case of 2° field and 470 and 630 mm in 10° field. the luminous efficiency curves thus predicted by the two deviation indices fitted very nicely to the experimentally determined luminous efficiency curves of all the observers. A way to utilize the deviation indices in practice where observers play an important role is proposed to avoid some confusion that may take place because of individual variation.     

Effects of EDTA saturated with Ca2+ (Ca-EDTA) on pig,bovine and mouse oocytes at the germinal vesicle stage during maturation culture and the involvement of chelation of Zn2+ in pronuclear formation induction by Ca-EDTA

EDTA saturated with Ca(2+), Fe(3+) or Cu(2+) can induce parthenogenetic activation of pig oocytes at the germinal vesicle stage, whereas EDTA saturated with Zn(2+), which is unable to chelate Zn(2+), does not, indicating that chelation of Zn(2+) with EDTA saturated with Ca(2+) (Ca-EDTA) in maturing pig oocytes plays a pivotal role in the induction of parthenogenetic activation of oocytes. In the present study, the involvement of Zn(2+) chelation in the induction of parthenogenetic activation of pig oocytes at the germinal vesicle stage was confirmed first by examining the effects of concomitant addition of Zn(2+), Cu(2+) or Ni(2+) at various concentrations together with 1 mmol Ca-EDTA l(-1) to the maturation medium. The titration experiments revealed that the pronuclear formation induced by 1 mmol Ca-EDTA l(-1) was completely inhibited by the addition of > 30 micromol Zn(2+) l(-1) to the medium, but not by the addition of Cu(2+) and Ni(2+) at any concentration examined. Second, bovine and mouse oocytes at the germinal vesicle stage were cultured in medium with or without 1 mmol Ca-EDTA l(-1) for 48 h to examine the effects of Ca-EDTA treatment on these oocytes during maturation culture. Most (70-86%) of the bovine oocytes that underwent germinal vesicle breakdown matured to the MII stage via the MI phase, regardless of whether Ca-EDTA was present for the first 24 h of culture. However, 61% of oocytes that had been cultured with Ca-EDTA for 48 h formed a pronucleus without a second polar body, whereas oocytes cultured in the absence of Ca-EDTA were not observed to form a pronucleus at any time during culture. However, even when mouse oocytes at the germinal vesicle stage were cultured for up to 48 h in maturation medium containing Ca-EDTA, pronuclear formation was not observed. Finally, when bovine oocytes that had been cultured with 1 mmol Ca-EDTA l(-1) for 48 h from the germinal vesicle stage were cultured further in medium without Ca-EDTA that was supplemented with 5% fetal calf serum, only 26% of the oocytes developed to the cleaved stage, and none could develop further.     

Package Design of Ready-to-Drink Coffee Beverages Based on Food <Emphasis Type="Italic">Kansei</Emphasis> Model—Effects of Straw and Cognition Terms on Consumer’s Pleasantness

To design a consumer-oriented package that complements the taste and aroma of ready-to-drink chilled-cup coffee beverages by using the food kansei model, the effects of the diameter and the color of drinking straws as well as the cognition terms of coffee on consumer sensory characteristics and preferences were investigated. Variance and factor analyses of the sensory scores for chilled-cup coffee with milk and sugar using straws of different diameters, as rated by consumer panelists, extracted two perceived factors (F1, contribution ratio 36.5%, and F2, 28.6%). A two-dimensional plot of the average F1 and F2 scores of 123 panelists showed that the perceived characteristics of the same taste and aroma varied according to the straw diameter. An image investigation of different straw colors and another sensory evaluation using “black,” “brown,” and “green” straws were also performed. A principal component analysis of the image data revealed that the sensory characteristics of coffee with milk and sugar were imaged from the straw color. The second evaluation suggested that the images of straw colors affected the sensory characteristics. In addition, cluster and multiple-comparison analyses of Internet research data from consumers regarding the cognition terms for coffee exhibited three clusters representing the cognitive characteristics of terms by consumers and by developers and the differences of attractiveness degree on the cognition terms due to the consumers’ personal attributes. These studies provide useful information for the development of packages of chilled-cup coffee beverages.     

Optical Spectra of Synthetic Spinels in the System MgAl2O4–MgCr2O4

Unpolarized optical spectra were measured in the wavelength range 322–1666 nm by the diffuse reflection technique from spinel powders synthesized in the system MgAl₂O₄–MgCr₂O₄. The spectra were interpreted by the crystal-field theory on the basis of trigonally distorted spinel octahedra with D_3d symmetry. For chromium-rich solid solutions, including the MgCr₂O₄ end-member, results after peak fittings showed octahedral D_3d local symmetry around Cr³⁺ ions, identical to the crystallographic site symmetry. For chromium-poor solid solutions, however, octahedral C_3v local symmetry was suggested around Cr³⁺ ions, different from the D_3d crystallographically expected.     

Performance of the nonisothermal fixed bed adsorption column with nonlinear isotherms

The cell model approach for the analysis of nonisothermal fixed bed adsorption column has been presented under the assumption that adsorption is controlled by intraparticle diffusion and adsorption equilibrium is nonlinear. The numerical analysis has been carried out by the Runge-Kutta-Gill scheme. With the aid of a HITAC-8800 computer, the influence of controlling variables of the breakthrough curves and temperature curves has been made clear for such parameters as solid phase mass transfer coefficient, overall heat transfer coefficient at the column wall, length of bed and the equilibrium isotherms. A nonisothermal adsorption column can be designed adequately by applying the numerical method developed here according to the cell model approach.     

Synthetic Molecular Gear Based on Double-Decker Porphyrin Complexes

New rotary molecular machines (1 and 2) were synthetically constructed from two distinct porphyrin-based rotors, a cerium(IV) bis(porphyrinate)s double-decker (CeDD) and a porphyrinatorhodium(III)-based rotor. These rotors are adjacently mounted on rotational axes aligned to near vertical as resembling the bevel-gear-shaped structure. Structural study using NMR analysis reveals that these distinct rotors are connected through a coordination bond between rhodium(III) and a pyridyl group. At temperature from 193 to 393 K, each rotor represents rotational motion driven by heat fluctuation without decomposition into the corresponding precursors in dichloromethane-d ₂ and tetrachloroethane-d ₄. Importantly, the mechanical interaction between the teeth of these rotors is strongly dependent on the central metal atom in a DD rotor and the teeth structure in a porphyrinatorhodium(III)-based rotor. Understanding such relationship between the chemical structures and mechanical interaction is of importance for generating cooperative motion in the hybrid machinery system.     

Preparation of regioisomers of structured TAG consisting of one mole of CLA and two moles of caprylic acid

TAG (MLM) with medium-chain FA (MCFA) at the 1,3-positions and long-chain FA (LCFA) at the 2-position, and TAG (LMM) with LCFA at the 1(3)-position and MCFA at 2,3(1)-positions are a pair of TAG regioisomers. Large-scale preparation of the two TAG regioisomers was attempted. A commercially available FFA mixture (FFA-CLA) containing 9-cis, 11-trans (9c, 11t)- and 10t,12c-CLA was selected as LCFA, and caprylic acid (C₈FA) was selected as MCFA. The MLM isomer was synthesized by acidolysis of acyglycerols (AG) containing two CLA isomers with C₈FA: A mixture of AG-CLA/C₈ FA (1∶10, mol/mol) and 4 wt% immobilized Rhizomucor miehei lipase was agitated at 30°C for 72 h. The ratio of MLM to total AG was 51.1 wt%. Meanwhile, LMM isomer was synthesized by acidolysis of tricaprylin with FFA-CLA: A mixture of tricaprylin/FFA-CLA (1∶2, mol/mol) and 4 wt% immobilized R. miehei lipase was agitated at 30°C for 24 h. The ratio of LMM to total AG was 51.8 wt%. MLM and LMM were purified from 1,968 and 813 g reaction mixtures by stepwise short-path distillation, respectively. Consequently, MLM was purified to 92.3% with 49.1% recovery, and LMM was purified to 93.2% with 52.3% recovery. Regiospecific analyses of MLM and LMM indicated that the 2-positions of MLM and LMM were 95.1 mol% LCFA and 98.3 mol% C₈ FA, respectively. The results showed that a process comprising lipase reaction and short-path distillation is effective for large-scale preparation of high-purity regiospecific TAG isomers.