A New SOI LDMOSFET Structure with a Trench in the Drift Region for a PDP Scan Driver IC

To improve the characteristics of breakdown voltage and specific on‐resistance, we propose a new structure for a LDMOSFET for a PDP scan driver IC based on silicon‐on‐insulator with a trench under the gate in the drift region. The trench reduces the electric field at the silicon surface under the gate edge in the drift region when the concentration of the drift region is high, and thereby increases the breakdown voltage and reduces the specific on‐resistance. The breakdown voltage and the specific on‐resistance of the fabricated device is 352 V and 18.8 m·cm² with a threshold voltage of 1.0 V. The breakdown voltage of the device in the on‐state is over 200 V and the saturation current at V_gs=5 V and V_ds=20 V is 16 mA with a gate width of 150 µm.     

Infection of epithelial cells by pathogenic neisseriae reduces the levels of multiple lysosomal constituents

Members of our group reported recently that neisseria infection of human epithelial cells results in accelerated degradation of the major lysosomal integral membrane protein LAMP1 and that this is due to hydrolysis of this glycoprotein at its immunoglobulin A1 (IgA1)-like hinge by the neisseria type 2 IgA1 protease (L. Lin et al., Mol. Microbiol. 24:1083-1094, 1997). We also reported that the IgA1 protease plays a major role in the ability of the pathogenic neisseriae to survive within epithelial cells and hypothesized that this is due to alteration of lysosomes as a result of protease-mediated LAMP1 degradation. In this study, we tested the hypothesis that neisseria infection leads to multiple changes in lysosomes. Here, we report that neisseria infection also reduces the levels of three other lysosomal markers: LAMP2, lysosomal acid phosphatase (LAP), and CD63. In contrast, neither the epidermal growth factor receptor level nor the beta-tubulin level is affected. A detailed examination of LAMP2 indicated that the reduced LAMP2 levels are not the result of an altered biosynthetic rate or of cleavage by the IgA1 protease. Nevertheless, the protease plays a role in reducing LAMP2 and LAP activity levels, as these are partially restored in cells infected with an iga mutant. We conclude that neisseria infection results in multiple changes to the lysosomes of infected epithelial cells and that these changes are likely an indirect result of IgA1 protease-mediated cleavage of LAMP1.     

Simultaneous occurrence of hereditary angioneurotic edema and Crohn disease

Hereditary C1 esterase inhibitor deficiency is often associated with immunpathologic disorders. The authors present a case of the rare coincidence of hereditary angioedema (HAE) and Crohn's disease. The history of the patient is analysed along with the familial occurrence of the disease. Characteristic abdominal manifestations of C1 esterase inhibitor deficiency are compared to the clinical signs of Crohn's disease. Differential diagnostic pitfalls are described along with efficatious therapeutic options.     

DS/CDMA signature sequences based on PR-QMF banks

In this paper, we propose two classes of multivalued signature sequences for direct sequence code division multiple access (DS/CDMA) systems. The proposed classes are obtained from the coefficients of the subbands of perfect reconstruction quadrature mirror filterbanks (PR-QMF). The first and second classes are derived from the tree and lattice structure PR-QMF banks, respectively, and they both have perfect correlation properties for synchronous DS/CDMA systems. The second class, in addition, has generally better correlation properties than other well-known sequences in asynchronous DS/CDMA systems. Some numerical results for the performance of the asynchronous DS/CDMA systems with several sequences, including the second class of sequences, are obtained.     

Ultrasonic properties of fluorosilicate glass-ceramics at cryogenic temperatures

The longitudinal ultrasonic wave velocity and attenuation, and shear wave velocity for machinable fluorosilicate glass-ceramic (MACOR) samples (regular shelf stock, annealed to 900°C, and 1000°C for 10 hrs) were measured as the functions of frequency and temperature with the pulse-echo method. The frequency and temperature range used were 5 MHz to 50 MHz, and 100 K to 300 K respectively. Both velocities for three samples decrease linearly with temperature, and the ultrasonic attenuation increases linearly with the frequency square, and decreases monotonically with increasing temperature. These data were used to calculate the elastic moduli, Lame parameter, and Poisson's ratio for the materials.     

New time-resolved techniques in two-photon microscopy

Microscopy is traditionally a tool for determining biological structures. Many recent advances in optical microscopy involves the incorporation of spectroscopy techniques to monitor biochemical states of microscopic structures in living cells and tissues. By minimizing tissue photodamage, two-photon excitation microscopy provides a new opportunity to study the dynamics of biological systems on time scales from nanoseconds to hours. This review will focus on a number of these new methods: two-photon time-lapse microscopy, two-photon photoactivation, two-photon correlated spectroscopy, two-photon single particle tracking and two-photon lifetime microscopy.     

Simple and efficient microstrip-to-waveguide transition

A new microstrip-to-waveguide transition is investigated experimentally. The coupling is achieved by virtue of a slot-coupled dielectric resonator (DR) at the microstrip-waveguide boundary. Since the DR loss is very small, the new transition can be operated efficiently. A net transition loss of 0.38 dB is obtained. The effects of the slot offset and slot length on the characteristics of the transition are measured and discussed     

Achievable diversity order by space-time trellis coding combined with MLED and OFDM over frequency selective fading channels

Space-time trellis code (STTC) in frequency selective fading channel using maximum likelihood equalization and detection (MLED), and orthogonal frequency division multiplexing (OFDM) are compared in this paper for channels with arbitrary delay profile. The performance bound for both schemes are first derived and their performances are compared both analytically and through simulations. Code design, receiver complexity, interleaver design and the robustness issues are addressed in these comparisons.     

A hybrid electronically coupled current comparator

A new versatile electronically coupled current comparator is presented in the paper. Its simpler design is more convenient for manufacturing yet it retains high accuracy in either manual or automated version. It provides a resolution of one part in 10/sup 6/ and has an estimated uncertainty less than 5/spl middot/10/sup -6/ in magnitude and less than 5 /spl mu/rad in phase at power frequencies.     

Electromechanical bending response of PZT/CNT-based polymer laminates subjected to concentrated load

This paper presents the electromechanical behavior of piezoelectric/carbon nanotube (CNT)-based polymer laminates under three-point bending. The laminate was fabricated using thin lead zirconate titanate (PZT) and multi-walled carbon nanotube (MWNT)-based polycarbonate layers. The three-point bending tests were conducted on the PZT/MWNT-based polycarbonate laminates, and the dependence of the displacement and output voltage due to mechanical loads on the nanotube content and the material dimensions were measured and discussed. The output power was then calculated. This study showed that the piezoelectric/CNT-based polymer laminates can generate power without external load resistance.