Series equivalence/operation of current-controlled boost-typesingle-phase voltage source converters for bidirectional power flow

Single-phase voltage source power converters (VSCs) under consideration are AC-DC current-controlled boost-type power converters with bidirectional power-handling capability. Equivalence between two series-connected two-level power converters and a single three-level power converter is considered here. Further considered is the series operation of three-level power converters. Simulation results and experimental verification for both are provided. Economical configurations of three-level power converters leading to multilevel waveforms are presented thereafter     

A wafer level monitoring method for plasma-charging damage usingantenna PMOSFET test structure

A novel monitoring method for plasma-charging damage is proposed. This method performs a quick and accurate evaluation using antenna PMOSFET. It was found that not only hot-carrier (HC) lifetime but transistor parameters such as initial gate current and substrate current were changed according to the degree of plasma-charging damage. However, the present work suggests that monitoring the shift of drain current after a few seconds of HC stress is a more accurate method to indicate plasma-charging damage. The monitoring method using the present test structure is demonstrated to be useful for realizing highly reliable devices     

Perineurioma: an unusual cause of an external auditory canal polyp

BACKGROUND: Home parenteral nutrition (HPN) is used to treat intestinal failure. A minority of HPN patients are dependent on opiates and benzodiazepines to control pain and anxiety. The aim of this study was to determine what effects such drug dependence had on patient outcomes. METHODS: Ten dependent patients were prospectively compared with 10 well-matched, nondependent HPN patients for the same 12-month period. Episodes of line sepsis and other complications were documented and the cost of treatment estimated. Health status was measured using the SF36 and EuroQol instruments. RESULTS: The dependent group had significantly more episodes of central line sepsis (p = .0007) as well as other complications (p = .0002). This led to significantly longer periods of inpatient care (p = .0004) and therefore higher costs of treatment. Health status was lower in the dependent group; they reported more pain (p = .04) and less energy (p = .04). CONCLUSIONS: The complication rate and increased cost of treatment for opiate- and sedative-dependent patients receiving HPN significantly detract from the overall outcome of this therapy.     

Biosynthesis of the escherichia coli K4 capsule polysaccharide. A parallel system for studies of glycosyltransferases in chondroitin formation

Escherichia coli K4 bacteria synthesize a capsule polysaccharide (GalNAc-GlcA(fructose))n with the carbohydrate backbone identical to chondroitin. GlcA- and GalNAc-transferase activities from the bacterial membrane were assayed with acceptors derived from the capsule polysaccharide and radiolabeled UDP-[14C]GlcA and UDP-[3H]GalNAc, respectively. It was shown that defructosylated oligosaccharides (chondroitin) could serve as substrates for both the GlcA- and the GalNAc-transferases. The radiolabeled products were completely degraded with chondroitinase AC; the [14C]GlcA unit could be removed by beta-D-glucuronidase, and the [3H]GalNAc could be removed by beta-N-acetylhexosaminidase. A fructosylated oligosaccharide acceptor tested for GlcA-transferase activity was found to be inactive. These results indicate that the chain elongation reaction of the K4 polysaccharide proceeds in the same way as the polymerization of the chondroitin chain, by the addition of the monosaccharide units one by one to the nonreducing end of the polymer. This makes the biosynthesis of the K4 polysaccharide an interesting parallel system for studies of chondroitin sulfate biosynthesis. In the biosynthesis of capsule polysaccharides from E. coli, a similar mechanism has earlier been demonstrated for polysialic acid (NeuNAc)n (Rohr, T. E., and Troy, F. A. (1980) J. Biol. Chem. 255, 2332-2342) and for the K5 polysaccharide (GlcAbeta1-4GlcNAcalpha1-4)n (Lidholt, K., Fjelstad, M., Jann, K., and Lindahl, U. (1994) Carbohydr. Res. 255, 87-101). In contrast, chain elongation of hyaluronan (GlcAbeta1-3GlcNAcbeta1-4)n is claimed to occur at the reducing end (Prehm, P. (1983) Biochem. J. 211, 181-189).     

Dimer interface of glutathione S-transferase from Arabidopsis thaliana: influence of the G-site architecture on the dimer interface and implications for classification

The three-dimensional structure of glutathione S-transferase from Arabidopsis thaliana has been solved at 2.2 A resolution (Reinemer et al., 1996). The enzyme forms a dimer of two identical subunits. The structure shows a new G-site architecture and a novel and unique dimer interface. Each monomer of the protein forms a separate G-site. Therefore, the requirements on the dimer interface are reduced. As a consequence, the interactions between the monomers are weaker and residues at the dimer interface are more variable. Thus, the dimer interface looses its relevance for a classification of plant glutathione S-transferases and the formation of heterodimers becomes even more difficult to predict.     

Electrical linewidth test structures fabricated in monocrystallinefilms for reference-material applications

The physical widths of reference features incorporated into electrical linewidth test structures patterned in films of monocrystalline silicon have been determined from Kelvin voltage measurements. The films in which the test structures are patterned are electrically insulated from the bulk-silicon substrate by a layer of silicon dioxide provided by SIMOX (Separation by the IMplantation of OXygen) processing. The motivation is to facilitate the development of linewidth reference materials for critical-dimension (CD) metrology-instrument calibration. The selection of the (110) orientation of the starting silicon and the orientation of the structures' features relative to the crystal lattice enable a lattice-plane-selective etch to generate reference-feature properties of rectangular cross section and atomically planar sidewalls. These properties are highly desirable for CD applications in which feature widths are certified with nanometer-level uncertainty for use by a diverse range of CD instruments. End applications include the development and calibration of new generations of CD instruments directed at controlling processes for manufacturing devices having sub-quarter-micrometer features     

A unified diode model for circuit simulation

A new commercially available diode model is described. This unified model is capable of simulating the widest range of diode technologies of any presently available. The emphasis of this paper is on describing the model's extensive features and flexibility in the different domains of operation and is of particular interest in power applications     

Performance evaluation of rule grouping on a real-time expertsystem architecture

Uses a Markov process to model a real-time expert system architecture characterized by message passing and event-driven scheduling. The model is applied to the performance evaluation of rule grouping for real-time expert systems running on this architecture. An optimizing algorithm based on Kernighan-Lin heuristic graph partitioning for the real-time architecture is developed and a demonstration system based on the model and algorithm has been developed and tested on a portion of the advanced GPS receiver (AGR) and manned manoeuvring unit (MMU) knowledge bases