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The opacity information of a finite-temperature plasma is an important property and requires the population distribution of a given plasma condition. A population kinetic code for plasma spectroscopy, FLYCHK, has been widely used by researchers to study the spectroscopic properties of high-energy-density plasmas under a wide range of conditions. In this study, the FLYCHK calculation of the Planck and Rosseland mean opacities of low- to high-Z elements, such as aluminum (Z = 13), iron (Z = 26), and gold (Z = 79), under a wide temperature and density range (T = 10−3–102 keV, ρ = 10−6–102 g/cc) is reported. This study mainly focused on the quantitative comparisons of FLYCHK opacities with commonly used opacities: ATOMIC and PROPACEOS. Comparisons show that the FLYCHK mean opacities are comparable to other results over a wide range of plasma conditions. Aluminum opacities were analyzed in detail to understand the characteristics of FLYCHK opacity simulations.

This study was undertaken to evaluate the allelopathic potential of 78 local Korean rice varieties on the height, leaf area, and straw and leaf dry weights of Echinochloa in a paddy field. Correlations between genetic and morphological characteristics of rice varieties and allelopathic potential were confirmed, with Buldo (56.1%) and Agudo (54.4%) showing the highest average inhibitory effects on barnyard grass. The average inhibition percentage on barnyard grass height, tiller number, total dry weight, straw dry weight, and leaf dry weight ranged from 5.1% to 31.3% depending on the variety. Various characteristics of the varieties showed different allelopathic effects. In crop morphology, there were no differences associated with the presence or absence of an awn, nor with the awn colour. The inhibitory effects for coloured hulls (16.0%) were greater than colourless hulls (23.9%). There was an increasing trend for inhibitory potential from late to early maturity of the variety. These results suggest that the allelopathic potential differed between rice varieties and that genetic and morphological rice characteristics could be used as selection markers for allelopathic rice varieties.

The action of riluzole, a neuroprotective drug, on cloned delayed rectifier K + channels (Kv1.5 and Kv3.1) was examined using the whole-cell patch-clamp technique. Riluzole reversibly inhibited Kv1.5 currents in a concentration-dependent manner with an IC 50 of 39.69±2.37μM. G-protein inhibitors (pertussis toxin and GDPβS) did not prevent this inhibition of riluzole on Kv1.5. No voltage-dependent inhibition by riluzole was found over the voltage range in which channels are fully activated. Riluzole shifted the steady-state inactivation curves of Kv1.5 in a hyperpolarizing direction in a concentration-dependent manner. It accelerated the deactivation kinetics of Kv1.5 in a concentration dependent-manner, but had no effect on the steady-state activation curve. Riluzole exhibited a use-independent inhibition of Kv1.5. The effects of riluzole on Kv3.1, the Shaw -type K + channel were also examined. Riluzole caused a concentration-dependent inhibition of Kv3.1 currents with an IC 50 of 120.98±9.74μM and also shifted the steady-state inactivation curve of Kv3.1 in the hyperpolarizing direction. Thus, riluzole inhibits both Kv1.5 and Kv3.1 currents in a concentration-dependent manner and interacts directly with Kv1.5 by preferentially binding to the inactivated and to the closed states of the channel.

Considering the slippage and the cavity detuning, we have investigated the bifurcation and the chaotic transitions in a FEL oscillator. In describing the nonlinear dissipative dynamics of the FEL oscillator, we have used the properly defined branching parameters, which are closely related to the physical parameters. Throughout this study, we have found three well-known chaotic transition routes via period-doubling cascade, intermittency, and quasiperiodicity, which are confirmed by the qualitative and quantitative analyses.

With one-dimensional Maxwell-Lorentz equations, we have investigated the bifurcations in a short-pulse free-electron laser oscillator. A generic Hopf bifurcations and chaotic transition via period-doubling cascade have been described in the parametric space of three branching parameters: the cavity detuning parameter D , the slippage parameter S , and the superradiant parameter K . The present theory of the period of limit-cycle oscillation in the radiation power is well consistent with recent experimental results.

For the 2-2.5-GeV Phang Light Source, a 12-period triple-bend achromat lattice is designed with flat dipole magnets to avoid possible difficulties associated with combined functions dipoles. In this arrangement, a quadrupole triplet is introduced per half achromat section for flexibility in tune and emittance. This lattice configuration yields weak sextupole strengths and shows good chromatic behavior in tune versus momentum. An electron beam emittance of 13*10/sup -9/ m-rad at 2 GeV is achieved with a large dynamic aperture. >

This research focuses on developing new implantable cardioverter defibrillator (ICD) dual lead configurations that reduce the defibrillation threshold (DFT) energy by delivering a second threshold shock in the area where the conventional shock's electric field is weakest. The objective of this study is to optimize electrode placements for lead systems including left-ventricular (LV) electrodes. A physiologically realistic 3D finite element model of the human thorax is employed to compute DFTs. The lead configurations investigated consist of a conventional lead system (TRIAD/sup TM/, Guidant Corporation) and additional LV shocking electrodes placed in the apical and basal portion of the posteriolateral coronary vein or directly within the TRIAD system's weak field region. The LV electrodes measure 50 mm in length and 1 mm in diameter. The computed DFT energy for the TRIAD is 6.2 J, falling within one standard deviation of the mean DFT reported in clinical studies using the TRIAD leads. LV leads located in the apical and basal portion of the posteriolateral coronary vein result in a DFT of 3.1 J, a 50% reduction from the TRIAD alone. LV leads placed in the anterior, middle, and posterior TRLAD weak field result in a DFT of 2.9 J, 2.7 J., and 3.5 J, respectively, corresponding to a 44-56% reduction in DFT from the TRIAD. The results indicate that an additional electrode placed in the proximity of the TRIAD weak field is just as effective in reducing DFTs as one placed directly within the weak field.

The patch-clamp technique was used to study the effects of nystatin on a cloned delayed rectifier potassium channel (Kv1.3) expressed in Chinese hamster ovary (CHO) cells. Kv1.3 currents recorded in the whole-cell configuration, using an intracellular solution containing nystatin, were subjected to a time- and concentration-dependent reduction in their amplitude and in the time constants of apparent inactivation. Direct application of nystatin to the cytoplasmic side of excised inside-out patches inhibited Kv1.3 currents and this inhibition was immediately reversible upon washout of the drug. In contrast, currents mediated by another delayed rectifier (Kv3.1) were not affected by this drug. The concentrations for nystatin and its structural analog, amphotericin B, required to produce half maximal inhibition (IC50) of the current were estimated to be about 3 and 60 microM, respectively. The effects of nystatin on the amplitude and inactivation of Kv1.3 currents were not voltage-dependent. In inside-out patches, tetraethylammonium (TEA) produced a rapid block of Kv1.3 currents upon the onset of a voltage pulse, while the inhibition by nystatin developed slowly. When co-applied with TEA, nystatin potentiated the extent of the TEA-dependent block, and the kinetic effect of nystatin was slowed by TEA. In summary, nystatin, a compound frequently used in perforated patch recordings to preserve intracellular dialyzable components, specifically inhibited the potassium channel Kv1.3 at concentrations well below those required for perforation. The site of this inhibition may be different from that for TEA and is readily accessible from the cytoplasmic side of the membrane.

The authors examine the performance of the so-called electron output scheme recently proposed by the Novosibirsk group. In this scheme, the key role of the FEL oscillator is to induce bunching, while an external undulator, called the radiator, then outcouples the bunched electron beam to optical energy via coherent emission. The level of the intracavity power in the oscillator is kept low by employing a transverse optical klystron (TOK) configuration, thus avoiding excessive thermal loading on the cavity mirrors. Time-dependent effects are important in the operation of the electron output scheme because high gain in the TOK oscillator leads to sideband instabilities and chaotic behavior. The authors have carried out an extensive simulation study by using 1D and 2D time-dependent codes and find that proper control of the oscillator cavity detuning and cavity loss results in high output bunching with a narrow spectral bandwidth. Large cavity detuning in the oscillator and tapering of the radiator undulator is necessary for the optimum output power.

The conductivity and resulting surface morphology of polypyrrole have been observed to change significantly with deposition rate (growth current density) and thickness, and to a lesser extent with anion species present. Previous results led to the conclusion that changes in the reaction kinetics occur during the growth of the polymer. Further evidence for this comes from the present preliminary infrared and Auger electron spectroscopy studies of the front and back surfaces of the polymer film. An attempt was made to detect chemical changes in the film and correlate them to an observed decay in conductivity when the film was left exposed to the atmosphere. Results show an increase in oxygen content, possibly due to hydroxyl ions, but no loss of the original dopant ion. Evidence is also found for the existence of carbonyl groups on the back (substrate) surface. Dendrite-like formations on the front surface of the films, which are much more pronounced with FeCl 4 − -doped films, contain much less anion than flat areas of the film, indicating that such formations may be caused by other polymer chain defects such as alpha-beta bonding or crosslinking.