A Hybrid Technique Combining FDTD and Series Solution for Near-to-Far-Field Transformation

A new near-to-far-field transformation that combines the FDTD and the series solution is presented. In this method, near-field data is calculated by FDTD and far-field data is also expressed by series solution. The boundary condition is applied to a virtual surface, which encloses arbitrarily shaped scatterers. In order to verify this method, scattering patterns from this transformation are compared with scattering patterns from exact solution. Numerical results show that errors in the far-field data from this method is less than surface equivalence theorem. Thus, this method is valid for obtaining the far-field data.     

Dielectric relaxations and electrical conductivities of poly(alkyl methacrylates) under high pressure

Dielectric properties of four methacrylate polymers (methyl, ethyl, n-butyl and n-octyl) were studied in the frequency range 0.0001 cps–300 kcps at temperatures above and below the glass transition temperature and at various pressures up to 2500 atm. At temperatures well above T_g a single relaxation peak (α′ peak) was observed in the case of the higher n-alkyl methacrylates. However, this peak was split into two peaks, α and β, with decrease in temperature or increase in pressure. The molecular motions corresponding to the α and the β relaxation processes are the micro-Brownian motions of amorphous main chains and of flexible side chains, respectively. From the temperature and the pressure dependence of the average dielectric relaxation time of these polymers the single relaxation process (the α′ process) was attributed to the micro-Brownian motion of the main chain coupled with that of the side chain. The effects of temperature and pressure on the d.c. conductivity of these polymers were also studied.     

Recent topics in total syntheses of natural dimeric naphthoquinone derivatives

This digest overviews successful synthetic approaches to natural dimeric 1,4-naphthoquinones. Several natural dimeric 1,4-naphthoquinone derivatives have been isolated from natural sources including plants, bacteria, and fungi. They have diverse structures and attractive biological activities. However, it is difficult to construct the dimeric scaffolds efficiently and selectively, because 1,4-naphthoquinones and their derivatives are highly reactive. Efficient and attractive synthetic methodologies to construct unique dimeric 1,4-naphthoquinone skeletons are reviewed.     

RGB‐Color Intensiometric Indicators to Visualize Spatiotemporal Dynamics of ATP in Single Cells

Adenosine triphosphate (ATP) provides energy for the regulation of multiple cellular processes in living organisms. Capturing the spatiotemporal dynamics of ATP in single cells is fundamental to our understanding of the mechanisms underlying cellular energy metabolism. However, it has remained challenging to visualize the dynamics of ATP in and between distinct intracellular organelles and its interplay with other signaling molecules. Using single fluorescent proteins, multicolor ATP indicators were developed, enabling the simultaneous visualization of subcellular ATP dynamics in the cytoplasm and mitochondria of cells derived from mammals, plants, and worms. Furthermore, in combination with additional fluorescent indicators, the dynamic interplay of ATP, cAMP, and Ca²⁺ could be visualized in activated brown adipocyte. This set of indicator tools will facilitate future research into energy metabolism.     

由从头算Hartree-Fock MO法对叔丁基过氧化氢与N,N-二甲苯胺反应机理的探讨

本文由从头算Hartree-Fock(STO-3G)MO法来探讨叔丁基过氧化氢(BHP)与N,N-二甲苯胺(DMA)的反应机理。该反应是由如下三种反应组成的。(1)DMA的N攻击BHP的O~1而形成N-氧化物(方式1);(2)生成氢键复合物(方式2);(3)由DMA的N攻击BHP的O~2而生成自由基(方式3)。上列三种的微挠能量经计算结果分别为0.2276、0.1687、0.2056 eV。因此,我们可得此三种反应机理的结论。     

Ab initio integrated multi-center molecular orbitals method for large cluster systems: total energy and normal vibration

A new computational scheme integrating multi-center ab initio molecular orbitals for determining total energy and normal vibration of large cluster systems is presented. This method can be used to treat large cluster systems such as solvents by quantum mechanics. The geometry parameters, the total energies, the relative energies, and the normal vibrations for four models of water cluster, the hydrated hydronium ion complex, and the transition state of proton transfer are calculated by the present method and are compared with those obtained by the full ab initio MO method. The results agree very well. The scheme proposed in this article is also intended to be used in modeling computer cluster systems using parallel algorithms.     

Investigation of cation-induced degradation of dye-sensitized solar cells for a new strategy to long-term stability

Current-voltage characteristics, electron lifetimes (tau), and electron diffusion coefficients (D) of dye-sensitized TiO2 solar cells (DSCs) composed of liquid electrolytes were repeatedly measured over a period of time. It was found that the energy conversion efficiency of the DSCs using electrolytes composed of Li+ or tetrabutylammonium cation as the counter charges of I-/I3- redox couples decreased with the lapse of time. On the other hand, such a decrease was not observed for the DSC consisting of 1,2-dimethyl-3-propylimidazolium cation or of Li+ coupled with the addition of tert-butylpyridine. The decrease of the efficiency was in accordance with a decreased electron lifetime. The notable decrease in the presence of Li+ is probably caused by the excess amount of Li+ adsorption on the TiO2 surface.     

Development of a Water-Dispersible Supramolecular Complex of Polyphenol with Polypeptides for Attenuation of the Allergic Response using a Mechanochemical Strategy

The prevalence of allergic disorders has increased worldwide in recent decades. Polyphenols, including resveratrol and curcumin, are posited to have potential as therapeutic agents for allergy; however, their use has been limited by poor water solubility. Accordingly, a highly concentrated, water dispersible, supramolecular complexes of polyphenols with polypeptides (poly-L-lysine, poly-γ-glutamic acid) and gelatin using high-speed vibration milling are developed. The complex exhibits resistance to photobleaching and thermal radiation. Treatment of a rat basophilic leukemia cell line (RBL-2H3) with polypeptide complexes containing resveratrol is suppressed allergic responses in vitro. Moreover, aerosolized administration of polypeptide complexes demonstrates excellent bioavailability and inhibition of immediate hypersensitivity reactions in ear tissue in vivo. Furthermore, the method avoids the use of organic solvent and therefore reduces undesirable biological responses.     

Study on Enzymatic Hydrolysis of Polylactic Acid by Endogenous Depolymerization Model

Enzymatic degradation of polylactic acid is studied experimentally and analytically. Gel permeation chromatography profiles obtained before and after the enzymatic degradation of polylactic acid (PLA) were introduced into the analysis based on a mathematical model. Previously developed techniques were successfully adapted to the analysis of an initial value problem consisting of an endogenous depolymerization model and an initial condition, and an inverse problem to determine the degradation rate for which the solution of the initial value problem also satisfies a final condition. Those problems were solved numerically and numerical results are introduced. Degradabilities of PLA and polyvinyl alcohol are compared.