Polysaccharide‐templated twisted assemble of 2‐anilinonaphthalene‐6‐sulfonic acid

Schizophyllan (SPG) is a natural β‐1,3‐glucan that forms a triple helix (t‐SPG) in neutral aqueous solutions and t‐SPG can be denatured to single chains (s‐SPGs) in DMSO or alkaline solutions. Exchanging the denatured solutions for neutral water leads the renaturation of the triple helix. We have reported that hydrophobic molecules can form a complex with s‐SPG when they are present in the renaturation process. Some of these, for example poly(dA) and polyaniline, were found to have aromatic amino moieties. This report demonstrates whether s‐SPG can interact with other aromatic amino compounds such as anilinonaphthalene sulfonic acid (ANS) derivatives. Enhanced fluorescence intensity and red‐shifted UV absorption spectra were observed in the mixture of s‐SPG and 2,6‐ANS or 2,6‐TNS. In the circular dichroism measurement, the positive Cotton effects appeared after mixing 2, 6‐ANS with s‐SPG. When the amino proton was replaced by the methyl group or used in intramolecular hydrogen bonds, any spectral changes were not observed. These results indicate that amino proton in the ANS derivatives plays a key role in the complexation. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1440–1448, 2008     

Ex-situ prepared films of 4-aminothiophenol on Au(1 1 1): photoemission, NEXAFS and STM measurements

Ex-situ prepared films of 4-aminothiophenol (4-ATP) on Au(1 1 1) have been studied by core-level photoemission using synchrotron radiation, ultra-high-vacuum scanning tunneling microscopy and spectroscopy (UHV-STM, STS), and X-ray absorption (NEXAFS). Photoemission measurements suggest that the film contains a relatively low percentage of 4-ATP bonded to the Au surface, with the presence of free 4-ATP, with oxidised and possibly dimerised molecules also present. We find a lower oxide content than has previously been observed, with well-resolved STM images. These images show a disruption of the long range order of the Au(1 1 1)-(22 × √3) reconstruction, with local nucleation of the reconstruction apparently induced by the 4-ATP, and bias-dependent contrast images. This latter effect, together with the asymmetry observed in STS, is ascribed to the presence of oriented molecular dipole layers between the metal and the organic material. NEXAFS data suggest a broadly upright geometry, with, however, considerable uncertainties.     

Computation of air flows and motion of environmental pollutants over complex geographical topographies

Importance and applicability of numerical flow analysis to environmental science are outlined. Fluid phenomena in the ocean, rivers, atmosphere and the ground are investigated by means of numerical methods and in turn proposals for the control, restoration and counterplans against the so-called environmental disrupters which disorder natural environment as well as ecological systems in nature. All such environmental disrupters diffuse in and are transported by environmental fluids. Those disrupters sometimes react on some other chemicals to generate offensive odor and even more poisonous materials. Environmental fluid dynamics is effective for the evaluation, prediction and restoration of the environmental damage. In this paper we focus our attention on the dynamical analysis of the diffusion and advection processes of environmental disrupters in environmental fluids. The first objective is to make an attempt to formulate a mathematical model for environmental fluids. The second objective is to exhibit some results of numerical simulations of the motion of offensive odor or pollutants in the atmosphere over a complex geographical topography.     

Magnetic-field-induced ferroelectric state in DyFeO3

Versatile and gigantic magnetoelectric (ME) phenomena have been found for a single crystal of DyFeO3. Below the antiferromagnetic ordering temperature of Dy moments, a linear-ME tensor component as large as alphazz approximately 2.4 x 10(-2) esu is observed. It is also revealed that application of magnetic field along the c axis induces a multiferroic (weakly ferromagnetic and ferroelectric) phase with magnetization [> or =0.5 microB/formula unit (f.u.)] and electric polarization (> or =0.2 microC/cm2) both along the c axis. Exchange striction working between adjacent Fe3+ and Dy3+ layers with the respective layered antiferromagnetic components is proposed as the origin of the ferroelectric polarization in the multiferroic phase.     

Total synthesis of 4-epi-atpenin A5 as a potent nematode complex II inhibitor

It is clear that atpenins and their analogs are useful chemical tools for elucidation of complex II functionality and that they could act as lead compounds for the development of novel helminth complex II-specific inhibitors. Recently, we discovered 4-epi-atpenin A5 as a potent nematode complex II inhibitor during our SAR studies of atpenin A5. This result led us to embark on a concise total synthesis of 4-epi-atpenin A5. In this study, we describe the total synthesis of 4-epi-atpenin A5. Importantly, this was more concise and practical synthesis than our previous total synthesis of atpenin A5.     

Commensurate-incommensurate crossover of charge stripe in La2-xSrxNiO4 (x approximately 1/3)

The temperature (T) dependence of the charge-stripe order in La2-xSrxNiO4 has been investigated in the vicinity of x approximately 1/3 by synchrotron radiation x-ray diffraction measurements. With decreasing T, a prominent commensurate-incommensurate (C-IC) crossover is observed in the x<1/3 region, while for the x>1/3 region the IC order is dominant over the whole T range. Such a C-IC crossover is interpreted as the entropy-driven self-doping of the charge stripes, and its x dependence indicates the clear electron-hole asymmetry with the x=1/3 compound as the Mott insulator.     

Effects of 2-Hydroxypropyl-b-cyclodextrin on Polymorphic Transition of Chlorpropamide in Various Conditions: Temperature, Humidity and Moulding Pressure

The amorphous complex of 2-hydroxypropyl--cyclodextrin (HP--CyD) with an oral hypoglycemic agent, chlorpropamide (CPM), in a molar ratio of 1:1 was prepared by the spray-drying method. The effects of storage (temperature and humidity) and moulding pressure on the polymorphic transition of CPM in HP--CyD matrix were investigated, in comparison with those of the CPM polymorphs, Form A (stable form) and Form C (metastable form). The formation of an amorphous complex of CPM with HP--CyD was confirmed by powder X-ray diffractometry and differential scanning calorimetry. During storage at various temperature and humidity conditions, the metastable Form C of CPM converted to the stable Form A, where the conversion proceeded according to the Jander equation with an activation energy of 51 kJ/mol (25–60–°C) and a reaction-order of 1.55 with respect to water content (relative humidity (RH) 20–75%). No polymorphic transition of Form A crystals was observed under the experimental conditions. In the case of the amorphous HP--CyD complex, Form C crystals were slowly produced, but the further conversion of the resulting Form C to Form A was markedly suppressed in HP--CyD matrix. Upon compression (2000kg/cm²), Forms A and C were converted to amorphous CPM in a major portion and Forms C and A, respectively, in a minor portion. The polymorphic transition behavior was clearly reflected in the dissolution rate of CPM, i.e., (1) the dissolution rate was in the order of HP--CyD complex (Form C) Form A, and (2) the dissolution rate of Forms A and C after the compression increased because of the conversion to amorphous state, while the complex maintained the fast dissolving property even after the compression. The results indicated that HP--CyD is useful not only for converting crystalline CPM to an amorphous substance, but also for maintaining the metastable form with fast dissolution rate, Form C, over a long period.     

Mechanism of substitution reaction on sp2-carbon center with lithium organocuprate

Theory and experiments suggest that the substitution reaction of a lithium dialkylcuprate(I) with an alkenyl bromide takes place through a pi-complex (cuprio(III)cyclopropane) that directly breaks down to the alkenylated product rather than via a conventional three-centered transition state. This mechanism is consistent with the broader mechanistic picture of the organocuprate reactions and accounts for the retentive stereochemistry and the kinetic isotope effect observed in the experiments.     

Nonlinear magneto-optical kerr rotation of an oxide superlattice with artificially broken symmetry

Simultaneously broken time-reversal and spatial-inversion symmetries can be realized in the epitaxially grown oxide "tricolor" superlattices composed of three sequential kinds of perovskite layers including a ferromagnetic one (manganese oxide). As a generic feature of such a system, the magnetic-field-induced second-harmonic generation and the resultant Kerr rotation of second-harmonic light were demonstrated. The signal intensity probes the interface magnetization of the superlattice, where temperature variation is shown to be distinct from the bulk feature.     

Coordinate-transformed and self-reproducible complex amplitudes inside laser cavities

We showed theoretically that coordinate transformation is effective in laser cavities because self-reproducible and coordinate-transformed complex amplitude pairs can exist in a laser cavity. Therefore, the intensity profiles in laser cavities can be designed within the limitations of the compatibility conditions.