Publications by authors named "Ting-Kai Chang"

Cuprous oxide (CuO) films are electrodeposited on fluorinated tin oxide (FTO) substrates with controlled crystallographic orientation and optimized film thickness. The CuO films exhibit a (100)-to-(111) texture change and a pyramid-to-cuboidal crystallite morphology transformation by increasing the electrodeposition current density. The cuboidal crystallites enclosed by (100) sidewalls and (111) truncated surfaces demonstrate better photoelectrochemical property than the pyramid crystallites.

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Plants of the species Gomphocarpus physocarpus, commonly known as balloon plant or swan plant, exhibiting virus-like symptoms of mosaic, mottle and crinkling were observed and collected in the southwestern part of Taiwan in 2015. Electron microscopic examination showed the presence of virus-like flexuous-rod particles. Potyvirus pinwheel-shape and laminated inclusion bodies were observed in the preparations of ultrathin sections of diseased leaves.

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A compact silicon polarization beam splitter (PBS) is proposed based on an asymmetrical directional coupler consisting of a wide waveguide and a dielectric loaded narrow waveguide. Given that TE and TM polarizations are the dominant mode in the wide and narrow waveguides, respectively, a perfect phase-matching condition in the TM mode but a huge phase mismatching in the TE mode can be achieved. Therefore, the TE mode is almost uncoupled regardless of device length but the TM mode can only completely couple to the cross port at an appropriate coupling length.

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We demonstrate wavelength-selective reflectors based on silicon microdisk resonators integrated with compact Y-branch splitters, using a CMOS-photonics technology. A high quality factor (Q) of ~ 88,000 was measured in the reflection spectrum for a 2.5-μm-radius device with a small footprint of 6 × 17 μm(2) and a wide free-spectral range (FSR) of over 41 nm.

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The structures and mechanism of action of many terpene cyclases are known, but no structures of diterpene cyclases have yet been reported. Here, we propose structural models based on bioinformatics, site-directed mutagenesis, domain swapping, enzyme inhibition, and spectroscopy that help explain the nature of diterpene cyclase structure, function, and evolution. Bacterial diterpene cyclases contain approximately 20 alpha-helices and the same conserved "QW" and DxDD motifs as in triterpene cyclases, indicating the presence of a betagamma barrel structure.

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Considerable effort has focused on the development of selective protein farnesyl transferase (FTase) and protein geranylgeranyl transferase (GGTase) inhibitors as cancer chemotherapeutics. Here, we report a new strategy for anticancer therapeutic agents involving inhibition of farnesyl diphosphate synthase (FPPS) and geranylgeranyl diphosphate synthase (GGPPS), the two enzymes upstream of FTase and GGTase, by lipophilic bisphosphonates. Due to dual site targeting and decreased polarity, the compounds have activities far greater than do current bisphosphonate drugs in inhibiting tumor cell growth and invasiveness, both in vitro and in vivo.

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We screened 26 bisphosphonates against a farnesyl diphosphate synthase from Plasmodium vivax, finding a poor correlation between enzyme and cell growth inhibition (R(2) = 0.06). To better predict cell activity data, we then used a combinatorial descriptor search in which pIC(50)(cell) = a pIC(50)(enzyme) + bB + cC + d, where B and C are descriptors (such as SlogP), and a-d are coefficients.

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