Ruthenium-catalyzed cross-coupling reactions between ketones and primary amines

Ketones react with primary amines in dioxane at 180 °C in the presence of a catalytic amount of a ruthenium catalyst to give the corresponding α-alkylated ketones in moderate to good yields. With alkyl(methyl) ketones, the alkylation takes place exclusively at less-hindered methyl position over α-methylene.     

Evaluation of performance and service life of low pressure lPG regulators for home use

This paper presents the evaluation of LPG (Liquefied petroleum gas) regulators for home use. For the evaluation, several properties of the regulators were experimentally analyzed, such as the operation of safety device, the adjusting and lock-up pressure, the adjusting spring and the diaphragm, with respect to the used time of the regulators. Experimental results showed that the initial operation performances of regulators were degraded with increase of the service time and also showed that the degradation of the performance and material property could become serious after about six-year-use of the regulators.     

Gallium-nitride microwave Doherty power amplifier with 40 W PEP and 68% PAE

A 40 W gallium-nitride microwave Doherty power amplifier for WCDMA repeater applications is presented. The main amplifier and peaking amplifier are implemented using two 20 W PEP GaN HEMTs. Performance is evaluated for broadband gain, power efficiency and adjacent-channel-power-ratio (ACPR). Experimental results of the GaN Doherty amplifier yielded a power gain of over 11 dB from 1.8 to 2.5 GHz, 68% power added efficiency at 40 W peak power. Good linearity performance of -48 dBc ACPR is obtained at a peak-to-average ratio of 9.8 dB.     

Reciprocal changes in p27(Kip1) and p21(Cip1) in growth inhibition mediated by blockade or overstimulation of epidermal growth factor receptors

Many human epithelial tumors express high levels of epidermal growth factor (EGF) receptors. A human-mouse chimeric version of anti-EGF receptor monoclonal antibody (mAb) C225, which blocks receptor activation and produces inhibition of cell proliferation, is currently being investigated in clinical trials. When cells bear high numbers of EGF receptors, either complete blockade of receptors with mAb 225 or full activation of receptors with EGF results in inhibition of proliferation. In the present study, we have explored the molecular mechanisms explaining how a receptor inhibitor, mAb 225, and a receptor activator, EGF, can both produce growth inhibition of A431 human squamous epithelial carcinoma cells. We reported previously that inhibition of A431 cells by EGF is associated with up-regulation of p21(Cip1). We now demonstrate that mAb 255-mediated inhibition is associated with up-regulation of p27(Kip1), which binds to and inactivates cyclin-dependent kinase-2 activity and produces cell cycle arrest in G1. Furthermore, inhibition by mAb 225 can be overcome by titrating the cultures with increasing concentrations of EGF, which is accompanied by a concurrent fall in the level of p27(Kip1). At properly titrated concentrations of mAb 225 and EGF, the inhibitory activities of both mAb 225 and EGF are counterbalanced and abolished. When EGF concentrations reach levels high enough to compete with mAb to produce near-saturating levels of receptor activation, p27(Kip1) falls below basal levels; however, the concomitant marked rise in the level of p21(Cip1) results in growth inhibition. Our data suggest that although p27(Kip1) and p21(Cip1) are induced and act independently, they play reciprocal roles in mediating inhibition of A431 cell growth by blockade of EGF receptors with mAb 225 and by activation of receptors with saturating concentrations of EGF.     

Axisymmetric modal analysis of liquid‐storage tanks considering compressibility effects

In this paper, we address analytical and numerical studies on the free vibration of fluid–structure interaction problems considering the fluid compressibility. According to the separation of variables together with the boundary condition enforcement, we first derive a compressible‐fluid velocity potential function. Next, we split the structure region into the wet and dry parts, for which we apply the Novozhilov thin shell theory. Combining two dynamic displacement fields, for two split structure parts, using the displacement compatibility conditions, we finally obtain a simultaneous equation system for computing natural frequencies and modes. According to the derived analytical formulae, we compute natural frequencies and modes, stress resultants, together with the comparison with the FEM analysis and the incompressible case. Numerical results show, compared to the incompressible case, that the compressible case produces lower natural frequencies and, furthermore, the relative difference is influenced by the slenderness of tanks and the relative liquid fill height. Copyright © 2002 John Wiley & Sons, Ltd.     

Dopant-free FUSI Pt/sub x/Si metal gate for high work function and reduced Fermi-level pinning

High work function (4.9 eV) on high-/spl kappa/ gate dielectric, which is suitable for bulk p-MOSFET, has been achieved using fully silicided (FUSI) Pt/sub x/Si gate without boron predoping of polysilicon. High concentration of Pt in FUSI Pt/sub x/Si using Ti capping layer on Pt in the FUSI process is a key to achieving high work function and reduced Fermi-level pinning on high-/spl kappa/ dielectric. By combining with substituted Al (SA) gate for nMOSFET, a wide range of work function difference (0.65 eV) between n and pMOSFETs is demonstrated, without any adverse effects of polysilicon predoping.     

High-power long-wavelength (λ~11.5 μm) quantum cascadelasers operating above room temperature

High-temperature operation (T=320 K) of quantum cascade lasers has been extended to 11.5-μm wavelengths with high performances. Peak-pulsed optical power of 55 mW is obtained at 300 K with a high T ₀=172 K, in good agreement with our theoretical model