A Flat Spectral Response AWG Demultiplexer Composed of Slabs with Islands and Peninsulas

Phase adjustment elements called islands and peninsulas are introduced to obtain an AWG demultiplexer with a flat spectral response. Use of the peninsulas enables us to achieve a 1dB bandwidth of 0.5 nm.     

A carbon-carbon bond formation using an endoperoxide of N-methoxy-carbonylpyrrole and a convenient synthesis of 4-alkylindoles

A convenient synthesis of 4-alkylindoles was attained by utilizing the result of a stannous chloride-effected reaction of endoperoxide of N-methoxycarbonylpyrrole with carbon nucleophiles.     

Microchip reversed-phase liquid chromatography with packed column and electrochemical flow cell using polystyrene/poly(dimethylsiloxane)

A microchip pressure-driven liquid chromatography (LC) with a packed column and an electrochemical flow cell has been developed by using polystyrene (PS) and poly(dimethylsiloxane) (PDMS). The cylindrical separation column with packed octadecyl silica particles was fabricated in the PS substrate. The three electrode system (working, reference, and counter electrode) for amperometric detection was fabricated onto the PS substrate, using the Au deposition, photolithography, and chemical etching. The detector flow cell was formed by sealing the electrode system with a PDMS chip containing a channel. In this flow cell, the effect of working electrode width (in the direction of flow) on chromatographic parameters, such as peak width and peak resolution were studied in electrode width ranging 50-5,000 microm. The effect of electrode width on sensitivity (current intensity, current density, and S/N ratio) was also examined. The sensitivity was discussed by simulating the concentration profile generated around the working electrode. The effects of the column packing size and the column size on the separation efficiency were examined. In this study, a good separation of three catechins was successfully achieved and the detection limits for (+)-catechin, epicatechin, and epigallocatechin gallate were 350, 450, and 160 nM, respectively.     

Synthetic study of hetisine-type aconite alkaloids. Part 3: Total synthesis of (±)-nominine

Completion of the total synthesis of (±)-nominine (1) is described in detail. Based on the results of the preceding two papers, total synthesis of (±)-nominine was accomplished diverging from the intermediate 7. Thus, following pyrrolidine ring formation through transformation from 7 to 8, the C-ring was constructed by radical cyclization to form 10 from the enyne precursor 9. Subsequent elaboration of the C-ring, followed by formation of the azabicyclic ring system, completed a total synthesis of (±)-1. Single-crystal X-ray analysis of (±)-1 unambiguously confirmed its molecular structure and racemic crystal structure.     

A new family of noncommutative 2-spheres

We give new examples of noncommutative manifolds. In particular we construct a “strong” deformation of C(S²), consisting of a family of noncommutative 2-spheres, and study their analytic and topological properties.     

Synthetic study of hetisine-type aconite alkaloids. Part 2: Preparation of hexacyclic compound lacking the C-ring of the hetisan skeleton

A hexacyclic compound 1, having almost the full hetisine-type aconite alkaloid framework lacking only the C-ring with an exo-methylene group, was synthesized from the intermediate 3 reported in the preceding paper. The synthesis involved the following key reactions the crucial conversion of 3 to 4, a stereoselective hydrocyanation reaction to obtain 5 from 4, and construction of the azabicyclic ring system (5→1).     

Hybridization energies of double strands composed of DNA, RNA, PNA and LNA

The electronic properties of double strands composed of trimeric LNA, PNA, DNA and RNA single strands were investigated by density-functional molecular orbital calculations. The computed hybridization energies for the double strands involving PNA or LNA are larger than those for DNA-DNA and RNA-RNA. The larger stability is attributed to the presence of a larger positive charge of the hydrogen atoms contributing to the hydrogen bonds in the PNA-DNA and LNA-DNA double-strands. These results are comparable to the experimental finding that PNA and LNA single strands display high affinity toward a complementary DNA or RNA single strand.