A new entry to functionalized cycloalkylamines: diastereoselective intramolecular amidoalkylation of N,O-acetal TMS ether possessing allylsilane

Highly diastereoselective cyclization (>20:1) as a new entry to functionalized cycloalkylamines has been conducted with acyclic N,O-acetal TMS ethers possessing an allylsilane moiety.     

High Differential Group Index of Dispersion Compensating Fibers for OCDMA Encoder/Decoder

We report the LPG pair device that can be used as a pulse duplicator or an OCDMA encoder/decoder. Due to the ring core region of dispersion compensating fiber (DCF), we can shorten the device length by a third and obtain surrounding insensitive LPG devices.     

Coordination polyhedron and chemical vapor deposition of Cu(hfacac)2(t-BuNH2)

A new pentacoordinate Cu(II) complex, Cu(hfacac)(2)(t-BuNH(2)) [hfacac = CF(3)C(O)CHC(O)CF(3)(-), t-BuNH(2) = tert-butylamine], has been synthesized and structurally characterized. Interestingly, the structure of a single crystal occurred as square pyramidal with one O atom at the apical position and one N and three O atoms at the basal positions, showing a serious degree of distortion. This contrasts with the square-pyramidal structure of Cu(hfacac)(2)L (L = H(2)O and pyrazine), which has the L ligand at the axial position. In the Cu(hfacac)(2)(t-BuNH(2)) complex, the t-BuNH(2) ligand is placed at an equatorial position with a lowered angle by 19.9(2) degrees from the basal plane. This distortion seems to reduce sigma influence and steric hindrance and so stabilizes the square-pyramidal geometry. This precursor has a lower melting point and superior stability to air, moisture, and heat than the Cu(hfacac)(2)(xH(2)O) precursor. The deposition rate of copper oxide film on a Pt layer above 450 degrees C was nearly constant with increasing temperature, indicating a mass transport limited reaction. Therefore it would be a useful metal organic chemical vapor deposition precursor for the fabrication of copper oxide film or superconducting materials. Crystal data for Cu(hfacac)(2)(t-BuNH(2)): 293(2) K, a = 9.6699(4) A, b = 18.0831(10) A, c = 12.8864(11) A, beta = 111.839(5) degrees, monoclinic, space group P2(1)/c, Z = 4.     

Forskolin promotes astroglial differentiation of human central neurocytoma cells

Human central neurocytoma is a kind of the brain tumors that are usually found in anterior part of the lateral ventricles. In this study, we established conditions that allowed proliferation of neurocytoma cells culture and analyzed characteristics of neurocytoma cells in vitro. For in vitro, a condition that used for culturing neural stem cells and contained basic fibroblast growth factor (bFGF) provided high proliferation. RT-PCR analaysis showed that nestin was found in neurocytoma cells, indicating that the neurocytomas possess neural stem cell properties. Interestingly, treatment of neurocytoma cells with forskolin increased expression of glial fibrillary acidic protein with a concomitant decrease in the nestin expression. Forskolin also induced morphological changes of neurocytoma cells to adopt an astrocyte-like phenotype. The results suggest that neurocyotma cells may have properties of multipotent neural stem cells.     

Hydrazide as a new hydrogen-bonding motif for resorcin[4]arene-based molecular capsules

The resorcin[4]arene-based benzoylhydrazide cavitands formed stable molecular capsules in nonpolar solvents by the eight intermolecular N-H...O=C hydrogen bondings, two from each four paired hydrazides, and the four intramolecular O-H2C-O...H-N hydrogen bondings on each cavitand. The stability of these molecular capsules depends on the encapsulated guest in the following order: CH3SO3(-) > CH3CO2(-) > CH3CH2NH2 x HCl approximately = CH3NH2 x HCl > (CH3)4N(+) > toluene > C2D2Cl4.     

High-speed temporal characterization and visualization of spatial light modulators and flat-panel displays

An apparatus that can characterize and visualize temporal dynamics of spatial light modulators (SLM's) and flat-panel displays is constructed and evaluated by use of a commercially available SLM. The apparatus is based on the stroboscopic video sampling method and has a temporal resolution of the order of microseconds, permitting measurement of a long event (>100ms) with a high signal-to-noise ratio. Experimental results demonstrate the visualization of the temporal image sequencing and addressing in an SLM.     

Plastic enzyme-linked immunosorbent assays (ELISA)-on-a-chip biosensor for botulinum neurotoxin A

A plastic ELISA-on-a-chip (EOC) employing the concept of cross-flow immuno-chromatographic analysis was applied to the measurement of botulinum neurotoxin A (BoNT/A) as agent for bio-terrorism. Two monoclonal antibodies specific to the heavy chain of the toxin were raised and identified to form sandwich binding complexes as the pair with the analyte. For the construction of an immuno-strip, one was utilized as the capture antibody immobilized onto nitrocellulose membrane and the other as the detection coupled to an enzyme, horseradish peroxidase. The two plates of EOC used in this study were fabricated by injection molding of polycarbonate to improve the reproducibility of manufacture and, after inclusion of the immuno-strip, bonded using a UV-sensitive adhesive. Under optimal conditions of analysis, the chip produced a color signal in proportion to the analyte dose and the signal was quantified using a detector equipped with a digital camera. From the dose-response curve, the detection limit of BoNT/A was 2.0 ng mL⁻¹, approximately five times more sensitive than a commercial-version detection kit employing colloidal gold tracer.     

Pilot-Scale Culture of Hypericum Perforatum L. Adventitious Roots in Airlift Bioreactors for the Production of Bioactive Compounds

Hypericum perforatum L. (St. John’s Wort) is an important medicinal plant which is widely used in the treatment for depression and irritable bowel syndrome. It is also used as a dietary supplement. Major bioactive phytochemicals of H. perforatum are phenolics and flavonoids. Quality of these phytochemicals is dramatically influenced by environmental and biological factors in the field grown plants. As an alternative, we have developed adventitious root cultures in large-scale bioreactors for the production of useful phytochemicals. Adventitious roots of H. perforatum were cultured in 500 l pilot-scale airlift bioreactors using half-strength Murashige and Skoog medium with an ammonium and nitrate ratio of 5:25 mM and supplemented with 1.0 mg l^?1 indole butyric acid, 0.1 mg l^?1 kinetin, and 3 % sucrose for the production of bioactive phenolics and flavonoids. Then 4.6 and 6.3 kg dry biomass were realized in the 500 l each of drum-type and balloon-type bioreactors, respectively. Accumulation of 66.9 mg g^?1 DW of total phenolics, 48.6 mg g^?1 DW of total flavonoids, 1.3 mg g^?1 DW of chlorogenic acid, 0.01 mg g^?1 DW of hyperin, 0.04 mg g^?1 DW of hypericin, and 0.01 mg g^?1 DW of quercetin could be achieved with adventitious roots cultured in 500 l balloon-type airlift bioreactors. Our findings demonstrate the possibilities of using H. perforatum adventitious root cultures for the production of useful phytochemicals to meet the demand of pharmaceutical and food industry.     

An olefin disconnection strategy for the practical synthesis of (+)-brefeldin A: olefin cross metathesis and intramolecular Horner-Wadsworth-Emmons olefination

The practical and convergent total synthesis of (+)-brefeldin A has been achieved by an olefin disconnection strategy. Key features of the total synthesis include the efficient formation of C2 and C10 olefins, employing an olefin cross metathesis (CM) reaction and an intramolecular HWE olefination, respectively.