A new approach toward light-harvesting reverse micelles from donor-acceptor miscible blends

In the present paper, we report a new approach toward light-harvesting reverse micellar systems from molecular blends of anthracene and perylene building blocks. The self-assembly initiated by protonation of the molecular blends gave rise to the mixed reverse micelles, in which intermolecular energy transfer from the anthracene to the perylene chromophores was observed. The atomic force microscope (AFM) studies on the reverse micelles prepared from the donor and acceptor blends at a range of the feed ratios showed a number of nanoscale-sized spherical objects homogeneously dispersed on the highly oriented pyrolytic graphite (HOPG) substrate. The critical micelle concentration (cmc) values of the reversed micelles at the donor:acceptor ratios of 100:0, 50:50, and 0:100 were estimated to be 7, 3, and 10 μM by fluorescence batch titrations, respectively, indicating that the cmc values should be almost equivalent regardless of the constitution of each chromophoric component. Attempt to generate the mixed reverse micelles through pairwise mixing of the donor- and acceptor-based reverse micelles resulted in spectral behaviors identical with those obtained by the self-assembly employing the donor-acceptor blends. This suggests that these two reverse micelles undergo thermodynamic exchange of the surfactant molecules to afford the mixed reverse micelles when mixing the two discrete reverse micellar systems.     

-symmetry for (r,s)-hypergeometric series

Contiguous operators for a two-parameter analogue of hypergeometric series are constructed. These represent a two-parameter quantum enveloping algebra introduced by Takeuchi.     

Recent Advance in Terahertz Wave and Material Basis

The unexplored terahertz (THz) region involves important phenomena of both fundamental and applied natures. Examples include phonon interactions, rotational transitions, and intermolecular dynamics. Frequency tunable high-power THz wave generation has been successfully achieved utilizing lattice resonance of LiNbO₃ and GaP crystals, respectively. Semiconductor devices utilizing the electron tunneling effect have also been developed.     

Integration of an electrochemical-based biolithography technique into an AFM system

An ordinary atomic force microscopy (AFM) was functionalized and applied to electrochemically draw micropatterns of biomolecules. To fabricate an electrochemical AFM probe having an electrode at the tip, a metal-coated AFM probe was first insulated with Parylene C, and then the apex of the tip was ground mechanically to expose the electrode. The effective electrode diameter was estimated to be ca. 500 nm. The electrode probe was positioned close to a heparin-coated antibiofouling substrate and used to locally generate hypobromous acid from a dilute Br⁻ solution to render the substrate surface protein-adhesive. In situ topographical imaging after the electrochemical treatment suggested the heparin layer became detached to allow the adsorption of proteins, in this case fibronectin. The diameter of the drawn fibronectin pattern was 2 μm, which is one order of magnitude smaller than we achieved previously using a microdisk electrode (tip diameter 10 μm). Figure AFM configuration integrated with the electrochemical-based surface modification and resultant micropatterns of fluorescence-labeled fibronectin Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Alloxazine as a ligand for selective binding to adenine opposite AP sites in DNA duplexes and analysis of single-nucleotide polymorphisms

Alloxazine can bind to adenine selectively over other nucleobases opposite an abasic site in DNA duplexes (5'-TCC AGX GCA AC-3'/3'-AGG TCN CGT TG-5', X=AP site, N=A, T, C, G) with a dissociation constant of 0.82 microM (pH 7.0, I=0.11 M, at 5 degrees C), and it is applicable to SNPs typing of PCR amplification products based on the binding-induced fluorescence response.     

Anisotropic growth of conducting polymers along heparin-modified surfaces

We have studied the possibility of making biocompatible, conductive patterns on a substrate by controlling the lateral growth rate of conducting polymers upon electropolymerization. Surface modification with heparin was found to enhance the lateral growth of polypyrrole, especially in the presence of dodecylbenzenesulfonate, and thus the micropatterning of heparin around electrodes leads to the formation of polypyrrole patterns.     

One-step synthesis of differently bis-functionalized isoxazoles by cycloaddition of carbamoylnitrile oxide with β-keto esters

A new protocol for synthesizing different functionalized isoxazoles is provided. Carbamoylnitrile oxide generated from nitroisoxazolone underwent inverse electron-demand 1,3-dipolar cycloaddition with 1,3-dicarbonyl compounds in the presence of magnesium acetate that formed magnesium enolate in situ. Although electron-deficient trifluoroacetoacetate did not undergo this cycloaddition under the same conditions, conversion to sodium enolate furnish the corresponding bis-functionalized trifluoromethylisoxazole. The DFT calculations using B3LYP 6-31G+(d,p) also supported the aforementioned reactivity.     

Highly selective binding of naphthyridine with a trifluoromethyl group to cytosine opposite an abasic site in DNA duplexes

We report on highly selective binding of a naphthyridine derivative with a trifluoromethyl group to cytosine opposite an abasic site in DNA duplexes; the binding-induced fluorescence quenching is applicable to the analysis of a C-related single-base mutation in DNAs amplified by PCR.     

Stimulated Raman hyperspectral imaging based on spectral filtering of broadband fiber laser pulses

We demonstrate a technique of hyperspectral imaging in stimulated Raman scattering (SRS) microscopy using a tunable optical filter, whose transmission wavelength can be varied quickly by a galvanometer mirror. Experimentally, broadband Yb fiber laser pulses are synchronized with picosecond Ti:sapphire pulses, and then spectrally filtered out by the filter. After amplification by fiber amplifiers, we obtain narrowband pulses with a spectral width of <3.3 cm(-1) and a wavelength tunability of >225 cm(-1). By using these pulses, we accomplish SRS imaging of polymer beads with spectral information.