An Annular Array MPT for Enhanced Generation of Omnidirectional SH Waves in a Plate

If guided wave transducers are fabricated in an annular array type, the excitation and measurement of target guided wave modes could be considerably enhanced (see, e.g., [1]). Accordingly, various annular array transducers have been developed, including those generating omnidirectional Lamb waves in a plate. Here, we newly consider an annular array type MPT (magnetostrictive patch transducer) to generate enhanced SH (shear-horizontal) waves in a plate. This annular array MPT is based on our earlier development of an omnidirectional SH wave MPT [2]. For wave field analysis by the annular array SH wave MPT, the strain response in a plate due to wave excitation by the MPT is calculated by using the Green’s function approach [3]. Using the analysis, an optimal configuration of the annular array MPT which can maximize the transducer output at the given frequency is determined. For the validation of numerical predictions, a series of experiments with varying frequencies were carried out and the numerical results were found to be in good agreement with the experimental results

Production of Transgenic Cloned Miniature Pigs with Membrane-bound Human Fas Ligand (FasL) by Somatic Cell Nuclear Transfer

Cell-mediated xenograft rejection, including NK cells and CD8+ CTL, is a major obstacle in successful pig-to-human xenotransplantation. Human CD8+ CTL and NK cells display high cytotoxicity for pig cells, mediated at least in part by the Fas/FasL pathway. To prevent cell-mediated xenocytotoxicity, a membrane-bound form of human FasL (mFasL) was generated as an inhibitor for CTL and NK cell cytotoxicity that could not be cleaved by metalloproteinase to produce putative soluble FasL. We produced two healthy transgenic pigs harboring the mFasL gene via somatic cell nuclear transfer (SCNT). In a cytotoxicity assay using transgenic clonal cell lines and transgenic pig ear cells, the rate of CD8+ CTL-mediated cytotoxicity was significantly reduced in transgenic pig's ear cells compared with that in normal minipig fetal fibroblasts. Our data indicate that grafts of transgenic pigs expressing membrane-bound human FasL control the cellular immune response to xenografts, creating a window of opportunity to facilitate xenograft survival

Korea's developmental program for superconductivity

Superconductivity research in Korea was firstly carried out in the late 70's by a research group in Seoul National University (SNU), who fabricated a small scale superconducting magnetic energy storage system under the financial support from Korea Electric Power Company (KEPCO). But a few researchers were involved in superconductivity research until the oxide high Tc superconductor was discovered by Bednorz and Mueller. After the discovery of YBaCuO superconductor operating above the boiling point of liquid nitrogen (77 K)(exp 2), Korean Ministry of Science and Technology (MOST) sponsored a special fund for the high Tc superconductivity research to universities and national research institutes by recognizing its importance. Scientists engaged in this project organized 'High Temperature Superconductivity Research Association (HITSRA)' for effective conducting of research. Its major functions are to coordinate research activities on high Tc superconductivity and organize the workshop for active exchange of information. During last seven years the major superconductivity research has been carried out through the coordination of HITSRA. The major parts of the Korea's superconductivity research program were related to high temperature superconductor and only a few groups were carrying out research on conventional superconductor technology, and Korea Atomic Energy Research Institute (KAERI) and Korea Electrotechnology Research Institute (KERI) have led this research. In this talk, the current status and future plans of superconductivity research in Korea will be reviewed based on the results presented in interim meeting of HITSRA, April 1-2, 1994. Taejeon, as well as the research activity of KAERI

Time-resolved photoluminescence of the size-controlled ZnO nanorods

Size dependence of the time-resolved photoluminescence (TRPL) has been investigated for the ZnO nanorods fabricated by catalyst-free metalorganic chemical vapor deposition. The nanorods have a diameter of 35 nm and lengths in the range of 150 nm to 1.1 mum. The TRPL decay rate decreases monotonically as the length of the nanorods increases in the range of 150 to 600 nm. Decrease of the radiative decay rate of the exciton-polariton has been invoked to account for the results

Quaternary semiconductor Cu2FeSnS4 nanoparticles as an alternative to Pt catalysts

We demonstrate an N719 dye sensitized solar cell based on Cu 2FeSnS4 (CFTS) as a counter electrode. The elements for the material are all earth abundant and environmentally benign. The power conversion efficiency of a DSSC using CFTS was comparable to that of a DSSC using Pt under A.M. 1.5G (100 mW cm-2).close3

Gastroprotective effects of the isopropanol extract of Artemisia princeps and its gastroretentive floating tablets on gastric mucosal injury

In this study, we investigated the gastroprotective effect of an isopropanol extract from the aerial parts of Artemisia princeps (IPAP) and developed a gastroretentive floating tablet of IPAP (IPAP-FR) for maximized local gastroprotective effects. Pre-treatment with IPAP ameliorated the gastric mucosal hemorrhagic lesions in ethanol/HCl- or indomethacin-treated rats. IPAP decreased mucosal hemorrhage of gastric ulcers induced by ethanol or indomethacin plus pyloric ligation in rats. The optimized floating tablet, IPAP-FR, floated on medium surface with more sustained eupatilin release compared to the non-floating control tablet. X-ray photographs in beagle dogs showed that IPAP-FR was retained for >2 h in the stomach. In the ethanol-induced gastric ulcer rat model, the gastric hemorrhagic lesion was improved more substantially with IPAP-FR compared to the non-floating control tablet. Based on these data, our data suggest that IPAP-FR has an improved therapeutic potential for the treatment of gastric ulcer