2,274 research outputs found

    Organic field-effect transistors by a wet-transferring method

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    Organic field-effect transistors (OFETs) were prepared from an epitaxially grown film fabricated by a wet-transferring process. 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrin platinum(II) was grown by thermal evaporation on the (001) surface of potassium bromide (KBr) single crystals. When the film was grown at room temperature, the planar molecules were aligned orthogonally on the crystal surfaces along the [110] direction with edge-on orientation to the surface normal direction. The epitaxy film was transferred to on SiO2/Si surface immediately after removing the KBr on the water surface to product the OFETs. The calculated µFET of the OFET for the wet-transferred vertically aligned film were 1.3×10–4 and 2.2×10–4 cm2 V–1 s–1 at the linear and saturation regions, respectively, at Vg = –50 V at an ION/IOFF (on/off ratios of source–drain current) of 104~105

    Two distinct red giant branch populations in the globular cluster NGC 2419 as tracers of a merger event in the Milky Way

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    Recent spectroscopic observations of the outer halo globular cluster (GC) NGC 2419 show that it is unique among GCs, in terms of chemical abundance patterns, and some suggest that it was originated in the nucleus of a dwarf galaxy. Here we show, from the Subaru narrow-band photometry employing a calcium filter, that the red giant-branch (RGB) of this GC is split into two distinct subpopulations. Comparison with spectroscopy has confirmed that the redder RGB stars in the hkhk[=(Cab)(by)-b)-(b-y)] index are enhanced in [Ca/H] by \sim0.2 dex compared to the bluer RGB stars. Our population model further indicates that the calcium-rich second generation stars are also enhanced in helium abundance by a large amount (Δ\DeltaY = 0.19). Our photometry, together with the results for other massive GCs (e.g., ω\omega Cen, M22, and NGC 1851), suggests that the discrete distribution of RGB stars in the hkhk index might be a universal characteristic of this growing group of peculiar GCs. The planned narrow-band calcium photometry for the Local Group dwarf galaxies would help to establish an empirical connection between these GCs and the primordial building blocks in the hierarchical merging paradigm of galaxy formation.Comment: 4 pages, 4 figures, 1 table, accepted for the publication in ApJ

    Tetra-μ-benzoato-bis­{[trans-1-(2-pyrid­yl)-2-(4-pyrid­yl)ethyl­ene]zinc(II)}

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    The paddle-wheel-type centrosymmetric dinuclear title complex, [Zn2(C7H5O2)4(C12H10N2)2], contains four bridging benzoate groups and two terminal trans-1-(2-pyrid­yl)-2-(4-pyrid­yl)ethyl­ene (L) ligands. The inversion center is located between the two ZnII atoms. The octa­hedral coordination around the ZnII atom, with four O atoms in the equatorial plane, is completed by an N atom of the L mol­ecule [Zn—N = 2.0198 (15) Å] and by the second ZnII atom [Zn⋯Zn = 2.971 (8) Å]. The ZnII atom is 0.372 Å out of the plane of the four coordinating O atoms

    A case of gangliocytic paraganglioma in the ampulla of Vater

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    <p>Abstract</p> <p>Background</p> <p>Duodenal gangliocytic paraganglioma is an extremely rare tumor and few cases have been reported to date.</p> <p>Case presentation</p> <p>The authors report a case of gangliocytic paraganglioma verified by post-op pathology after pancreaticoduodenectomy for a tumor in the ampulla of Vater. The 56-year-old male patient concerned visited our emergency room with melena that started one week prior to hospitalization. The patient was diagnosed to have a tumor in the ampulla of Vater with bleeding on its surface. However post-op, he was diagnosed as having gangliocytic paraganglioma by immunohistochemistry.</p> <p>Conclusion</p> <p>This tumor has precise clinical implications, and if continuous follow up is conducted after careful diagnosis and surgical treatment, invasive major operations, such as, radical pancreaticoduodenectomy can be avoided.</p

    Prolonged Activation of ERK Contributes to the Photorejuvenation Effect in Photodynamic Therapy in Human Dermal Fibroblasts

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    Photodynamic therapy (PDT) is known to be effective in the photorejuvenation of photoaged skin. However, the molecular mechanisms of rejuvenation by PDT remain elusive. In this study, we aimed to understand the molecular events occurring during the photorejuvenation after PDT in dermal fibroblasts in vitro. First, we found that PDT conditions resulted in an increased fibroblast proliferation and motility in vitro. Under this condition, cells had increased intracellular reactive oxygen species (ROS) production. Importantly, PDT induced a prolonged activation of extracellular signal–regulated kinase (ERK) with a corresponding increase in matrix metalloproteinase (MMP)-3 and collagen type Iα messenger RNA and protein. Moreover, inhibition of PDT-induced ERK activation significantly suppressed fibroblast proliferation and expression of MMP-3 and collagen type Iα following PDT. In addition, NAC (an antioxidant) inhibited PDT-induced fibroblast proliferation and ERK activation indicating that prolonged ERK activation and intracellular ROS contribute to the proliferation of fibroblasts and the dermal remodeling process for skin rejuvenation. We also identified increased collagen volume and decreased elastotic materials that are used as markers of photoaging in human skin samples using histochemical studies. Results from this study suggest that intracellular ROS stimulated by PDT in dermal fibroblasts lead to prolonged activation of ERK and, eventually, fibroblast proliferation and activation. Our data thus reveal a molecular mechanism underlying the skin rejuvenation effect of PDT

    All-optical polymeric interferferometric wavelength converter comprising an excited state intra-molecular proton transfer dye

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    We designed and demonstrated an all-optical wavelength converter using a polymeric Mach–Zehnder interferometer (MZI) comprised of an excited state intramolecular proton transfer (ESIPT) dye, 2,2-{oxybis[4-(4-methoxyphenyl)quinoline-6,2-diyl]}bis(5-methoxyphenol) (MQ). This MZI wavelength converter is composed of the MQ dye-doped polymeric waveguide and a thick light blocking metal film. A feature of this device is that one arm of the MZI can be irradiated by 355 nm pulses (signal beam), while the other arm was not, thus allowing a differential phase shift in the submicrosecond time scale. Because of the refractive index change of the ESIPT dye in one arm of interferometer upon irradiation with the signal beam, phase modulation of the continuous-wave probe light propagating in the irradiated arm of the MZI takes place, leading to the intensity modulation at the output defined by the signal beam, resulting in an all-optical wavelength converter, that is, the conversion of the signal modulation to output signal modulation of the probe light of the MZI. The characteristics of the wavelength converter are well described by a simple kinetic model.This work was performed with support from the Ministry of Commerce, Industry, and Energy of Korea
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