Encapsulation of anilinonaphthalenesulfonates in carboxylate-terminated PAMAM dendrimer at the polarized water|1,2-dichloroethane interface

Molecular encapsulation of water-soluble anionic fluorescent dye molecules, 8-anilino-1-naphthalenesulfonic acid (ANS), and its bimolecular derivative (bis-ANS), in the generation 3.5 polyamidoamine (G3.5 PAMAM) dendrimer was investigated in the bulk aqueous phase and at the polarized water|1,2-dichloroethane interface. ANS(-) was electrostatically incorporated in the dendrimer, and the fluorescence enhancement with a blue shift of the emission maximum was observed at pH values <6, where the interior of the dendrimer was positively charged. The fluorescence enhancement of ANS was maximized around pH 3 and then decreased under more acidic conditions. The potential dependences of the molecular encapsulation and the interfacial mechanism were studied in detail by means of potential modulated fluorescence (PMF) spectroscopy. Under acidic conditions, the dendrimer incorporated ANS(-) at the positively polarized interface as well as in the aqueous phase. ANS(-) was released from the dendrimer at the intrinsic transfer potential and independently transferred across the interface. Bis-ANS exhibited relatively strong interaction with the dendrimer over a wide pH range (1 < pH < 8), and a negative shift of the transfer potential was observed under the corresponding pH condition. The PMF analysis clearly demonstrated that the interfacial mechanism of the dendrimer involves transfer and adsorption processes depending on the pH condition and the Galvani potential difference.     

On partial disjunction properties of theories containing Peano arithmetic

Let \(\varGamma \) be a class of formulas. We say that a theory T in classical logic has the \(\varGamma \)-disjunction property if for any \(\varGamma \) sentences \(\varphi \) and \(\psi \), either \(T \vdash \varphi \) or \(T \vdash \psi \) whenever \(T \vdash \varphi \vee \psi \). First, we characterize the \(\varGamma \)-disjunction property in terms of the notion of partial conservativity. Secondly, we prove a model theoretic characterization result for \(\varSigma _n\)-disjunction property. Thirdly, we investigate relationships between partial disjunction properties and several other properties of theories containing Peano arithmetic. Finally, we investigate unprovability of formalized partial disjunction properties.     

Unique incorporation behavior of amino acid-type surfactant into phospholipid vesicle membrane

The incorporation behavior of some anionic surfactants, including amino acid-type surfactants, on phospholipid vesicles was investigated. This was done by measuring the release of a vesicle-entrapped fluorescence probe and the scattered light intensities of vesicle particles in the surfactant solution as a function of surfactant concentration and time. Sodium dodecyl sulfate, sodium dodecanesulfonate, sodium dodecanoyl sarcosinate, and sodium dodecanoyl glutamate were employed in this study. All surfactants ruptured the phospholipid vesicle at around each critical micelle concentration by mixed micelle formation with phospholipid. While leakage of the fluorescence probe took place at a very low concentration in the sulfate- or sulfonate-type surfactant systems, it occurred at the concentration just below the CMC in the amino acid-type surfactant systems. Kinetic analysis of the release of the probe from the vesicles showed that the former surfactants adsorbed independently and homogeneously onto the phospholipid vesicles, while the latter surfactants were cooperatively incorporated.     

Synthesis of phthalides and 3,4-dihydroisocoumarins using the palladium-catalyzed intramolecular benzannulation strategy

A novel method for the synthesis of phthalides and 3,4-dihydroisocoumarins via the palladium-catalyzed intramolecular benzannulation of bis-enyne and enyne-diyne systems is described. Various kinds of substituted phthalides 9 and 17 and 3,4-dihydroisocoumarins 19 were synthesized from 8, 16, and 18, respectively, in moderate to excellent yields. The benzannulation reaction proceeded chemoselectively to give the corresponding fused ring compounds A without the formation of the regioisomeric products B (eq 6). Furthermore, this methodology was applied to the synthesis of biologically active 3-n-butylphthalide 23.     

A metastable de-excitation spectroscopy (MDS) study on oxygen adsorption on a polycrystalline zirconium surface

The adsorption of oxygen on a polycrystalline zirconium surface at room temperature has been studied by metastable de-excitation spectroscopy (MDS) in conjunction with UPS and AES. From the analysis of the measured spectra, we have shown the following. (1) At the initial stage of oxygen adsorption (exposure <1.2 L), the surface density of states (SDOS) of zirconium changes little at around the Fermi level (E_F), while it decreases appreciably at 1–2 eV below E_F (E_B=1–2 eV) by oxygen adsorption. (2) The SDOS at E_B=0–2 eV decreases with increasing oxygen exposure at >1.2 L and disappears at >8 L. (3) The oxygen 2p states (E_B=5–8 eV) are localized at the subsurface region at oxygen exposure 0–2 L. (4) The ZrO₂ phase appears at the outermost zirconium surface at around 2 L, then grows with increasing exposure, and finally dominates at >8 L. It is suggested that two different phases (ZrO₂ phase and that in which oxygen occupies subsurface sites) coexist at the outermost surface at 2–8 L.     

Wavelength division with three-dimensional couplers fabricated by filamentation of femtosecond laser pulses

Refractive-index changes can be induced by filamentation of 800-nm, 1-kHz femtosecond laser pulses in silica glass. Two-dimensional translation of a 40-microm-long filament leads to the formation of a curved waveguide because of bending by the previously induced refractive-index change. The fabrication of 2-mm directional couplers to split the coupled beam into 1:1 at a wavelength of 632.8 nm is demonstrated. The realization of three-dimensional directional couplers and wavelength division in the output from the couplers is also demonstrated.     

Metastable helium atom stimulated desorption of H+ Ion

H+ desorption induced by the impact of metastable helium atoms has been found for H(2)O/Na/Ni(110) coadsorption systems. The measurements were carried out using a time-of-flight technique and a pulsed-discharge type metastable helium atom ( He(*)) source. It is concluded that the H+ desorption by He(*) is induced by a hole created on the valence levels via the Auger deexcitation of He(*). The H+ desorption by He(*) may be understood within the framework of the Menzel-Gomer-Readhead model.     

Nickel(0)-catalyzed dimerization of ethyl cyclopropylideneacetates

The dimerization of ethyl cyclopropylideneacetates proceeded in the presence of Ni(0) catalysts, and cyclic compounds or linear compounds were formed in selective manners. The structures of products were highly dependent on the structure of the substrate and the ligands bound to the catalyst. The mechanism of the reactions was discussed in detail.     

Optical Characteristics of Hybrid Macrocycles with Dithienogermole and Tricoordinate Boron Units

The introduction of unconventional elements into π-conjugated systems has been studied to manipulate the electronic states and properties of compounds. Herein, boron- and germanium-containing hybrid macrocycles, as a new class of element-hybrid conjugated systems, have been synthesized. The palladium-catalyzed Stille cross coupling of bis(bromothienyl)borane and bis(trimethylstannylthienyl)- or bis(trimethylstannylphenyl)-substituted dithienogermoles as the boron- and germanium-containing building blocks, respectively, produced a mixture of several macrocyclic compounds. Single-crystal X-ray analysis of the 2:2 coupling product revealed a planar structure with a cavity inside the macrocycle. The optical properties of the macrocyclic products indicated rather small electronic interactions between the building units. However, intramolecular photoenergy transfer from the dithienogermole unit to the boron unit was clearly observed with respect to the fluorescence spectra.