Modular fluorescence sensors for saccharides

Modular and modular polymer supported fluorescence photoinduced electron transfer (PET) sensors 2 and 3 with two boronic acid receptor units, a pyren-1-yl fluorophore, and hexamethylene linker show selective saccharide binding in aqueous methanolic solution at pH 8.21.     

An improved method for constructing a full-length enriched cDNA library using small amounts of total RNA as a starting material

We have developed an improved method for constructing a full-length cDNA library using small quantity of material by modifying the original oligo-capping method. In our devised method, total RNAs are used in sequential oligo-capping steps directly without preliminary mRNA purification. Using this method, we constructed full- length cDNA libraries from 100 mg of total RNA. These libraries contained 8x10(5) to 8x10(6) independent clones with average insert sizes of 2.0 kb. Moreover, the number of full-length cDNAs containing the translation initiation codon ATG in the constructed libraries was estimated to 60-70%. In addition, 54% of the known cDNAs had a longer 5' end than the corresponding genes in the public database. Our results show that the method can be effectively used to construct full-length enriched cDNA libraries, especially, if starting material is limited.     

Sphingosine mediates FTY720-induced apoptosis in LLC-PK1 cells

FTY720, a synthetic sphingoid base analog, was examined as a new sphingosine kinase inhibitor, which converts endogenous sphingosine into its phosphate form. With 20 microM of FTY720, sphingosine accumulated in the LLC-PK(1) cells in a time- and dose-dependent manner. The FTY720 treated cells showed a high concentration of fragmented DNA, a high caspase-3 like activity and TUNEL staining cells. It was also found that the sphingosine and sphinganine level increased in a time- and dose-dependent manner within 12 h after the FTY720 treatment. The sphingosine kinase activity was reduced by FTY720 as much as other sphingosine kinase inhibitors, N, N-dimethylsphingosine (DMS), dl-threo-dihydrosphingosine (DHS). The fragmented DNA content as a result of the 20 microM of FTY720 treatment and by 5 microM of the exogenously added BSA-sphingosine complex indicated typical apoptosis. Under similar conditions, the accumulated sphingosine concentration in all the cells was almost identical even though the sphingosine distribution inside the cells was somewhat different. These results indicate that the FTY720 induced apoptosis is associated with the inhibition of the sphingosine kinase activity and is strongly associated with the successive accumulation of sphingosine.     

Fabrication of solid thin film electrolyte and LiCoO2 by aerosol flame pyrolysis deposition

Aerosol flame pyrolysis deposition method was applied to deposit the oxide glass electrolyte film and LiCoO₂ cathode for thin film type Li-ion secondary battery. The thicknesses of as-deposited porous LiCoO₂ and Li₂O–B₂O₃–P₂O₅ electrolyte film were about 6 μm and 15 μm, respectively. The deposited LiCoO₂ was sintered for 2 min at 700 °C to make partially densified cathode layer, and the deposited Li₂O–P₂O₅–B₂O₃ glass film completely densified by the sintering at 700 °C for 1 h. After solid state sintering process the thicknesses were reduced to approximately 4 μm and 6 μm, respectively. The cathode and electrolyte layers were deposited by continuous deposition process and integrated into a layer by co-sintering. It was demonstrated that Aerosol flame deposition is one of the good candidates for the fabrication of thin film battery.     

Characterization of n-butyl acrylate centered triads in poly(n-butyl acrylate-co-carbon monoxide-co-ethylene) by isotopic labeling and two dimensional NMR

Poly(n-butylacrylate-co-carbon monoxide-co-ethylene) (polyEBC) samples prepared from 13C-labeled monomer, n-butyl acrylate, were characterized using two dimensional (2D) pulsed field gradient (PFG) 750 MHz NMR spectroscopy. To elucidate the complex structure of the terpolymer, 2D-1H/13C-heteronuclear single quantum coherence (HSQC) and heteronuclear multiple bond correlation (HMBC) experiments were conducted by selectively exciting the enhanced resonances in the spectra of two polymer samples, one polymer resulting from synthesis with 1-13C-n-butylacrylate monomer and a second polymer obtained from a synthesis with 2-13C-n-butylacrylate monomer. High-resolution 2D-NMR combined with 13C-labeling of the polymer greatly simplifies the 2D-NMR spectra, selectively enhances the weak peaks from low occurrence B-centered triad structures, and aids in their resonance assignments. In all experiments, the sample temperature was 120 degrees C, to ensure a homogeneous solution and sufficient molecular mobility. Electronic Supplementary Material: Supplementary material (1D 13C NMR spectra of the 13C-labeled and unlabeled polymers) is available in the online version of this article at http://dx.doi.org/100.1007/s00216-003-2402-3.     

Synthesis and Characterization of Fluoro- and Chloro- bimetallic Alkoxides as Precursors for Luminescent Metal Oxide Materials via Sol-Gel Technique

Heterobimetallic alkoxides are broadly recognized as versatile precursors for luminescence materials, and efforts are being made to develop novel routes by applying the concept of geometrical molecular design, for their synthesis and to design a single source precursor suited to photoluminescent materials. Novel and new series of bimetallic alkoxides has been prepared by metathesis route. They exhibit a lower sensitivity towards hydrolysis and so they are easier to handle as compared to other alkoxides. All the compounds were characterized by elemental analysis, FT-IR and multinuclear NMR spectroscopies. FT-IR revealed that the molecular structure of these metal alkoxides was retained to a large extent in 4 ： 1 halogenated alcohol-benzene solution. The heteronuclear NMR spectroscopy provided useful information about chemical shifts for better understanding the likely structure based on interactions with their coordinate metals. The mass spectra show similar types of fragmentation pattern. SEM-EDS analyses showed consistency with the formulation. XRD patterns show an enhanced homogeneity at high temperature. TGA measurements show that thermal decomposition occured in steps that depended entirely on the chemical compositions and the synthesis routes. SEM observation reveals that the morphology and particle size strongly depend on synthesis routes for their precursors.     

Photochemical reactions of a dimethacrylate compound containing a chalcone moiety in the main chain

We synthesized the new photosensitive oligomer containing a chalcone moiety in the main chain by end-capping reaction of diepoxide compound with methacrylic acid. The chalcone-epoxy oligomeric compound was synthesized with 4,4^′-dihydroxychalcone and epichlorohydrin. Investigation of the photosensitivity of the newly synthesized chalcone oligomer was carried out by using UV-Vis absorption and infrared spectroscopies under UV exposure. We observed the photodimerization behavior under UV irradiation. At the same time, we could also observe the photopolymerization of the compound with a trace amount of dimethoxyphenyl acetophenone. Thermal properties of UV-cured dimethacrylate compounds were also studied.     

The use of a thermally reversible bond for molecular imprinting of silica spheres

A silica monomer-estrone complex (EstSi) having a thermally cleavable urethane bond and a cross-linkable triethoxysilane group was synthesized. From EstSi and TEOS, spherical silica particles with sizes of 1.5-3 mum were prepared. The template molecules were removed from the silica matrix by heating at 180 degrees C in DMSO in the presence of water, generating a cavity with an amino group. The control silica particles that had the same sizes and shapes were obtained with aminopropyl triethoxysilane and TEOS. When ethylene glycol was added in place of H2O, an ethyl alcoholic group was formed in the cavity. Their recognition ability and specific binding for estrone were characterized by uptake experiments. The estrone-imprinted silica particles showed a much higher recognition ability than the control silica particles and higher selectivity for estrone than testosterone propionate.     

Depigmenting activity and low cytotoxicity of alkoxy benzoates or alkoxy cinnamte in cultured melanocytes

To obtain effective and safe topical depigmenting agents, we synthesized hydroxybenzoates, alkoxybenzoates, and 3,4,5-trimethoxycinnamate containing a thymol moiety and screened then for high-level inhibitory activity against melanin synthesis in cultured melanocytes. Eight compounds were tested for their depigmenting effect and cytotoxicity using a murine melanocyte cell line. We found that 3,4,5-trialkoxybenzoates and 3,4,5-trimethoxycinnamate, synthesized by conjugating 3,4,5-trialkoxybenzoic acids and 3,4,5-trimethoxycinnmic acid with thymol, showed a potent depigmenting effect and low cytotoxicity. Compound 4h, 5-methyl-2-(methylethyl)phenyl (2E)-3-(3,4,5-trimethoxyphenyl)prop-2-enoate, showed the most potent depigmenting effect (IC50=10 microM) with low cytotoxicity (IC50=200 microM).