High Helicobacter pylori eradication rate with a 1-week regimen containing ranitidine bismuth citrate

HSR-903 is a newly synthesized quinolone antibacterial agent with low toxicity. The biliary and urinary excretion of unchanged HSR-903, its R-isomer, and their glucuronides was determined after iv bolus administration (5 mg/kg) to normal Sprague-Dawley rats (SDR) and Eisai hyperbilirubinemic mutant rats (EHBR). The values for the biliary excretion clearance of HSR-903 and its glucuronide in EHBR were decreased to approximately 40 and 2% of those in SDR, respectively, whereas the values for the urinary excretion clearance of HSR-903 and its glucuronide were comparable in SDR and EHBR. The biliary excretion clearance values for the R-isomer and its glucuronide were approximately 3 times greater than those for HSR-903. These results demonstrated that the enantiomers of HSR-903 and their conjugates were excreted into bile in a stereospecific manner. The hepatic uptake of [14C]HSR-903 in vivo was evaluated by means of integration plot analysis. The results indicated that the hepatic uptake of [14C]HSR-903 was very fast and was blood flow-limited. To clarify the mechanism of excretion of HSR-903 into bile, the uptake and efflux of [14C]HSR-903 were studied using isolated hepatocytes from SDR and EHBR. The initial uptake of HSR-903 by hepatocytes was temperature-dependent, saturable, and stereospecific. Unlabeled HSR-903 (S-isomer), the R-isomer, grepafloxacin, and sparfloxacin significantly inhibited the uptake of [14C]HSR-903. The efflux of [14C]HSR-903 from hepatocytes from EHBR was significantly slower than that from hepatocytes from SDR. The addition of sodium azide or bromosulfophthalein reduced the efflux of [14C]HSR-903. These results demonstrate that HSR-903 is actively excreted into bile via the canalicular multispecific organic anion transporter, which is deficient in EHBR.     

High field-effect mobility in n-channel Si face 4H-SiC MOSFETs with gate oxide grown on aluminum ion-implanted material

We report investigations of Si face 4H-SiC MOSFETs with aluminum (Al) ion-implanted gate channels. High-quality SiO/sub 2/-SiC interfaces are obtained both when the gate oxide is grown on p-type epitaxial material and when grown on ion-implanted regions. A peak field-effect mobility of 170 cm/sup 2//V/spl middot/s is extracted from transistors with epitaxially grown channel region of doping 5/spl times/10/sup 15/ cm/sup -3/. Transistors with implanted gate channels with an Al concentration of 1/spl times/10/sup 17/ cm/sup -3/ exhibit peak field-effect mobility of 100 cm/sup 2//V/spl middot/s, while the mobility is 51 cm/sup 2//V/spl middot/s for an Al concentration of 5/spl times/10/sup 17/ cm/sup -3/. The mobility reduction with increasing acceptor density follows the same functional relationship as in n-channel Si MOSFETs.     

High-power-density 4H-SiC RF MOSFETs

The authors have made the first 4H-SiC RF power MOSFETs with cutoff frequency up to 12 GHz, delivering RF power of 1.9 W/mm at 3 GHz. The transistors withstand 200 V drain voltage, are normally off, and show no gate lag, which is often encountered in SiC MESFETs. The measured devices have a single drain finger and a double gate finger, and a total gate width of 0.8 mm. To their knowledge, this is the first time that power densities above 1 W/mm at 3 GHz are reported for SiC MOSFETs.     

Fabrication of planar polymer waveguides for evanescent-wave sensing in aqueous environments

We present a detailed account of processing issues related to fabrication of optical waveguide sensors intended for evanescent-wave sensing in aqueous solutions or surface-bound fluorescence excitation in biological samples. The waveguides consist of a polymer layer on top of a fluoropolymer (Cytop^™) cladding. The fluoropolymer is closely index-matched to water, providing a symmetric cladding environment which simplifies optical excitation and provides tunability in penetration depth not available with other evanescent-wave techniques. We present methods of controlling the wettability of the fluoropolymer surface and improving adhesion to the core waveguide layer. Furthermore, we demonstrate the application of the waveguide structure to fluorescence imaging of cultured cells.