Arrhythmogenic right ventricular cardiomyopathy underlies syndrome of right bundle branch block, ST-segment elevation, and sudden death

In all experimental mammals tested (rats, dogs, primates), intramuscular injections of the oil-soluble antimalarial artemisinin derivatives artemether and arteether have produced an unusual pattern of selective damage to brain stem centers predominantly involved in auditory processing and vestibular reflexes. Artesunate, the most widely used of these compounds, is a water soluble hemisuccinate derivative given parenterally either by intravenous or intramuscular injection. The neurotoxic potential of parenteral artesunate and artemether was compared in a murine model. Adult Swiss albino mice were assigned randomly to 28-day regimens of intramuscular artemether or artesunate in doses ranging from 30 to 100 mg/kg/day. At 30 mg/kg/day, no abnormalities were detected with either drug. At 50 mg/kg/day, abnormalities were observed in six of 12 artemether recipients and two of 12 artesunate recipients. These were reversible in all but one (artemether) mouse. At 100 mg/kg/day, eight of 36 artemether recipients, two of 36 artesunate recipients, and one of 18 control mice died. All but four surviving mice in the artemether group (86%) showed obvious and usually irreversible abnormalities of balance and equilibrium, whereas only four artesunate recipients (11%) exhibited abnormalities, and these were reversible in each case (P < 0.001). At this dose the relative risk (95% confidence interval) for death or disability was 5.3 (2.6-11.2) for artemether recipients. Intramuscular artemether is significantly more neurotoxic than intramuscular artesunate in this murine model.     

Gene transfer into muscle by electroporation in vivo

Among the nonviral techniques for gene transfer in vivo, the direct injection of plasmid DNA into muscle is simple, inexpensive, and safe. Applications of this method have been limited by the relatively low expression levels of the transferred gene. We investigated the applicability of in vivo electroporation for gene transfer into muscle, using plasmid DNA expressing interleukin-5 (IL-5) as the vector. The tibialis anterior muscles of mice were injected with the plasmid DNA, and then a pair of electrode needles were inserted into the DNA injection site to deliver electric pulses. Five days later, the serum IL-5 levels were assayed. Mice that did not receive electroporation had serum levels of 0.2 ng/ml. Electroporation enhanced the levels to over 20 ng/ml. Histochemical analysis of muscles injected with a lacZ expression plasmid showed that in vivo electroporation increased both the number of muscle fibers taking up plasmid DNA and the copy number of plasmids introduced into the cells. These results demonstrate that gene transfer into muscle by electroporation in vivo is more efficient than simple intramuscular DNA injection.     

Observation of iron silicide formation by plan-view transmission electron microscopy

The formation and the phase transitions of iron silicide by solid-phase epitaxy have been investigated by means of plan-view transmission electron microscopy, which enables us to observe a clean interface between Fe and Si. Layers of Fe were deposited on Si (100) at room temperature in an ultrahigh vacuum chamber. The sample was annealed in the electron microscope at a temperature between 673 and 1073 K. After annealing at 673 K, FeSi crystallites were formed with various orientations. When the annealing temperature was increased to 973 K, we found that the crystallites suddenly started to coalesce into grains of several hundreds of nanometers in size and polycrystalline beta-FeSi2 was formed. These phase transitions were also confirmed with electron energy-loss spectroscopy.     

Symbolic dynamics of a chaotic neuron model

Chaotic neurons change their internal state according to a bimodal map, and when they communicate with other neurons their internal state is transformed into one of two separate outputs, firing or resting. We address and investigate the topological entropy of the two-valued output of the chaotic neuron from two different viewpoints: the dependence upon the parameters of the neurons, and the relationship to their threshold. From the former viewpoint, we clarify the mechanism that changes the shift space corresponding to the time series of the neuronal output. From the latter viewpoint, we examine the effect of small fluctuations on the threshold of the chaotic neuron. This work was presented in part at the 7th International Symposium on Artificial Life and Robotics, Oita, Japan, January 16–18, 2002     

Modeling birdsong learning with a chaotic Elman network

Among passerines, Bengali finches are known to sing extremely complex courtship songs with three hierarchical structures: namely, the element, the chunk, and the syntax. In this work, we theoretically studied the mechanism of the song of Bengali finches in aides to provide a dynamic view of the development of birdsong learning. We first constructed a model of the Elman network with chaotic neurons that successfully learned the supervisor signal defined by a simple finite-state syntax. Second, we focused on the process of individual-specific increases in the complexity of song syntax. We propose a new learning algorithm to produce the intrinsic diversification of song syntax without a supervisor on the basis of the itinerant dynamics of chaotic neural networks and the Hebbian learning rule. The emergence of novel syntax modifying the acquired syntax is demonstrated. This work was presented in part at the 11th International Symposium on Artificial Life and Robotics, Oita, Japan, January 23–25, 2006     

Weighted Homo-Lumo Energy Separations for the Polyene References of Fullerenes with Up to 100 Carbon Atoms

The T value represents the HOMO-LUMO energy separation of a ε-electronic system weighted with the number of conjugated atoms. We found that this value is kept almost constant for the polyene references defined graph-theoretically for isolated-pentagon isomers of fullerenes with up to 100 carbon atoms. on this numerical basis, the T value can safely be considered as a realistic index of kinetic stability or chemical inertness for all fullerenes without abutting pentagons.     

Model experiment of upward leaders-shielding effects of tallobjects

Discharges originating from laboratory upward leaders are studied experimentally with a configuration consisting of two parallel vertical rods at ground and an elevated plane. The flashover probability of each rod, the effect of gap configuration on that probability, and the shielding effect of the taller rod on the smaller one are investigated. Experimental results are analyzed, taking into account the deviation of time to flashover of the gap. Application of the results to the case of natural lightning is also discussed     

Formation and corrosion of InP/In contacts in hydrochloric acid

Flatband potentials, charge carrier concentrations and their frequency dispersions of p-type and n-type InP in 1.0 M HCl were determined. The cathodic decomposition of InP in this acidic solution is compared with the deposition process of indium from 1.0 M-HCl containing 0.1 M InCl₃. The share of the involved reactions, hydrogen evolution, InP decomposition and indium deposition are investigated. The reaction rates are generally smaller on p-type InP and the reaction speed is much slower but the principal reactions are the same. The kinetics of the indium deposition and dissolution are studied in detail. These reactions are discussed in terms of the preparation of watersplitting photoelectrodes with modified surfaces.     

Zone drawn NEW-TPI thermoplastic polyimide and its blends with Xydar liquid crystalline polymer

In this work we report the effects of single stage zone drawing on the properties of NEW-TPI thermoplastic polyimide homopolymer, and its blends with Amoco's Xydar liquid crystalline polymer. Zone drawing was performed first on homopolymer NEW-TPI films to determine the effect of load weight, heater speed, and drawing temperature on the attainable draw ratio. Degree of crystallinity and chain orientation increase as the draw ratio increases for NEW-TPI. Blends of NEW-TPI/Xydar compositions 90/10 and 70/30 were studied next. In blends, the Xydar component is not molecularly dispersed, and is initially preferentially oriented along the machine direction during the film processing stage. Xydar acts as a nucleation site and lowers the temperature for crystallization of the NEW-TPI from the rubbery amorphous state. Zone drawing was performed either parallel or perpendicular to Xydar's initial preferred orientation direction. Blends with lower Xydar fraction could be zone-drawn to higher ratios. Zone drawing perpendicular to Xydar's initial orientation direction also resulted in increased draw ratio. Dynamic mechanical properties of the zone drawn materials were studied. In homopolymer NEW-TPI, dynamic modulus increased by a factor of two to 4.0 GPa in zone drawn films, largely as a result of the formation of oriented crystallites. In the blends, the modulus parallel to Xydar's initial orientation direction was greater than that in the transverse direction. Depending upon composition and test direction, zone drawing increased the dynamic moduli of the blends from 1.5 up to 2.7 times, in the temperature range from 150°C to 300°C.     

Josephson vortex timing circuit

We have studied a new timing circuit in which the input signal is put out at the same time as the clock signal. This is a key element for the realisation of Josephson vortex logic. We propose a new device structure which consists of two Josephson transmission lines connected by a resistor and a vortex trapping site (VTS). In this device a signal vortex is trapped in the VTS and it is repropagated to the output when the clock signal vortex propagates to the turning point. The quasistatic operation of this device is confirmed experimentally.