Static-state feedback control of discrete-event systems underpartial observation

Studies static-state feedback control of discrete-event systems under partial observation. The authors present a necessary and sufficient condition for the existence of a static-state feedback controller. A static controller is a special case of a dynamic controller studied by Kumar et al. The authors' condition, however, has computational advantage in contrast to those obtained by Kumar et al. The authors also present a necessary and sufficient condition under which the modular feedback synthesis is possible     

Basic fibroblast growth factor as one of the essential factors regulating lens transdifferentiation of pigmented epithelial cells

In vitro transdifferentiation of retinal pigmented epithelial cells of the chick embryo into lens cells can be markedly enhanced by culture in the presence of testicular hyaluronidase and phenylthiourea. Since the commercial preparations of hyaluronidase that had previously been used were very crude, a search for the actual effective molecule(s) enhancing lens transdifferentiation was conducted. First, we purified the enzyme and tested the effect of the purified hyaluronidase. Highly purified hyaluronidase itself did not enhance lens transdifferentiation. The crude hyaluronidase was then separated according to affinity with heparin, considering the possibility that the fibroblast growth factor (FGF) is contained in the crude hyaluronidase. Transdifferentiation-enhancing activity was detected in the fraction which was bound to heparin and eluted with 2 M NaCl, where no hyaluronate-degrading activity existed. Analysis of the fraction by SDS-PAGE revealed the existence of an 18 kDa protein whose NH2-terminal sequence was identical to that of basic FGF. The basic FGF derived from bovine brain also enhanced lens transdifferentiation of pigmented epithelial cells. These findings suggest that basic FGF must play a major role in enhancing transdifferentiation of pigmented epithelial cells to lens cells.     

Thermal instability of Bi-Pb-Sr-Ca-Cu-O superconductor around 650δC

Bi_0.85Pb_0.15Sr_0.8CaCu_1.4O _y superconductor was quenched to room temperature after annealing at several temperatures in air. From the initial magnetization curve measurement for the annealed samples, it was found that the volume fraction of superconducting phases of the sample annealed at 650°C greatly decreased. TEM observation revealed that a second phase often appeared in the grain-boundary region for the sample annealed at 700°C. The second phase was identified as Bi₁Pb₂Sr_2.6Ca_1.6O _y by energy dispersive spectroscopy.     

A video DSP with a macroblock-level-pipeline and a SIMD typevector-pipeline architecture for MPEG2 CODEC

A video DSP with macroblock-level-pipeline and a SIMD type vector-pipeline architecture (VDSP2) has been developed, using 0.5 μm triple-layer-metal CMOS technology. This 17.00 mm×15.00 mm chip consists of 2.5 M transistors, and operates at 100 MHz. The real-time encoder and decoder specified in the MPEG2 main profile at the main level can be realized with two VDSP2's and a motion estimation (ME) unit, and one VDSP2 respectively, at an 80 MHz clock rate, with a total power dissipation of 4.2 W at 3.3 V     

Pulmonary sequestration receiving arterial supply from the right coronary artery. A case report

Pulmonary sequestration is a relatively rare anomaly. The arterial supply usually is derived from the aorta or its major branches. We present a 65-year-old female patient with pulmonary sequestration receiving arterial supply from the right coronary artery, complicated with sick sinus syndrome.     

Regulation of Kv4.2 and Kv1.4 K+ channel expression by myocardial hypertrophic factors in cultured newborn rat ventricular cells

Postnatal development and myocardial hypertrophy are associated with alterations in cardiac voltage-gated K+ channels. To investigate mechanisms underlying this K+ channel remodeling, expression of Kv4.2 and Kv1.4 K+ channel alpha-subunits was examined in cultured newborn rat ventricular myocytes by Western blot analysis using polyclonal antibodies against each of the subunits. At day 5 of cell culture, Kv1.4 protein was expressed at higher level than Kv4.2; as the age of culture progressed, Kv1.4 was significantly diminished while Kv4.2 increased with time in culture and became the predominant K+ channel protein. Such K+ channel isoform switch from Kv1.4 to Kv4.2 resembles that of the development in vivo. A 72-h treatment with exogenous triiodothyronine (T3, 0.1 microM) to cultured neonatal myocytes enhanced the expression of Kv4.2 by 73% and decreased the Kv1.4 expression by 22%. The effects of T3 were associated with an increase in the protein-to-DNA ratio indicating myocyte hypertrophy. On the other hand, a 72-h treatment with cardiac non-myocyte cell (NMC)-conditioned growth medium (NCGM) or phenylephrine (20 microM) induced similar cell hypertrophy, but in sharp contrast to T3, both markedly suppressed the Kv4.2 channel protein level. In addition, the trophic and the Kv4.2-downregulating effects of NCGM could be mimicked by exogenous endothelin-1 (0.1 microM), a paracrine factor secreted from cardiac NMCs. Our observations for the first time suggest that cardiac Kv4.2 and Kv1.4 K+ channel alpha-subunits are differentially regulated by a variety of myocardial hypertrophic factors. That T3 accelerated the developmental K+ channel isoform switch from Kv1.4 to Kv4.2 in vitro indicates the critical importance of thyroid hormone in postnatal K+ channel remodeling. Cardiac NMCs and alpha-adrenoceptor activation may contribute to the reduced outward K+ channel density in hypertrophied cardiomyocytes.     

Effects of thermal modification on the structural properties of thermotropic liquid crystalline copolyester and phenoxy resin blends

The effects of thermal modification on the structural properties were studied for a poly(ethylene terephthalate-co-p-hydroxybenzoic acid) liquid crystal bended with phenoxy resin. Poor miscibility and phase separation between the blend components are observed by the temperature dependence of dynamic mechanical properties of sample molded at 260°C, over the composition range studied. The miscibility of the blends is increased by molding at 280°C, and the blends molded by increasing the processing time show a dynamic mechanical transition to a homogeneous blend. These changes are the result of an interchange reaction between the blend components. A rubbery modulus has been observed for such blends. This implies the formation of cross-linked structures that accompany the interchange reactions.     

Mechanical dispersion of crosslinked polymers reinforced with randomly distributed short fiber

The dynamic viscoelastic properties of composites reinforced with randomly distributed short glass and carbon fibers were studied in relation to the dependence on the fiber length, the mixing ratio of glass fibers of different length, and the kind of polymer matrix. Although the composite reinforced with glass fiber of 0.05 mm in length shows only one dispersion (α) corresponding to the primary transition of polymer matrix, those reinforced with 3- and 10-mm glass fibers, and those reinforced with the mixture of 10- and 0.05-mm glass fibers are characterized by two additional dispersions (α′ and α″) which appear on the lower frequency side or higher temperature side of the α-dispersion. The composite reinforced with 3-mm carbon fiber does not show the additional dispersions. The α′- and α″-dispersions appear irrespective of the kind of matrix polymer.