Normal levels of prepulse inhibition in the euthymic phase of bipolar disorder.

BACKGROUND:Deficits in prepulse inhibition (PPI) of the acoustic startle response have been suggested as a potentially useful endophenotype for schizophrenia spectrum disorders and may explain certain symptoms and cognitive deficits observed in the psychoses. PPI deficits have also been found in mania, but it remains to be confirmed whether this dysfunction is present in the euthymic phase of bipolar disorder.METHOD: Twenty-three adult patients with DSM-IV bipolar disorder were compared to 20 controls on tests of acoustic startle reactivity and PPI of the startle response. Sociodemographic and treatment variables were recorded and symptom scores assessed using the Hamilton Depression Inventory and the Young Mania Rating Scale.RESULTS:Overall, the patient and control groups demonstrated similar levels of startle reactivity and PPI, although there was a trend for the inter-stimulus interval to differentially affect levels of PPI in the two groups.CONCLUSIONS: In contrast to bipolar patients experiencing a manic episode, general levels of PPI were normal in this euthymic sample. Further studies are required to confirm this finding and to determine the mechanisms by which this potential disruption/normalization occurs. It is suggested that an examination of PPI in a high-risk group is required to fully discount dysfunctional PPI as a potentially useful endophenotype for bipolar disorder.

A phase 2 study of high-activity 186Re-HEDP with autologous peripheral blood stem cell transplant in progressive hormone-refractory prostate cancer metastatic to bone

Purpose: We investigated the potential for improvement in disease control by use of autologous peripheral blood stem cell transplant (PBSCT) to permit administration of high activities of 186Re-hydroxyethylidene diphosphonate (HEDP) in patients with progressive hormone-refractory prostate cancer (HRPC).

Methods: Eligible patients had progressive HRPC metastatic to bone, good performance status and minimal soft tissue disease. Patients received 5,000 MBq of 186Re-HEDP i.v., followed 14 days later by PBSCT. Response was assessed using PSA, survival, pain scores and quality of life.

Results: Thirty-eight patients with a median age of 67 years (range 50–77) and a median PSA of 57 ng/ml (range 4–3,628) received a median activity of 4,978 MBq 186Re-HEDP (range 4,770–5,100 MBq). The most serious toxicity was short-lived grade 3 thrombocytopenia in 8 (21%) patients. The median survival of the group is 21 months (95%CI 18–24 months) with Kaplan-Meier estimated 1- and 2-year survival rates of 83% and 40% respectively. Thirty-one patients (81%, 95% CI 66–90%) had stable or reduced PSA levels 3 months post therapy while 11 (29%, 95% CI 15–49%) had PSA reductions of >50% lasting >4 weeks. Quality of life measures were stable or improved in 27 (66%) at 3 months.

Conclusion: We have shown that it is feasible and safe to deliver high-activity radioisotope therapy with PBSCT to men with metastatic HRPC. Response rates and survival data are encouraging; however, further research is needed to define optimal role of this treatment approach.

Human Papillomavirus Type 16 E6 and E7 Cause Polyploidy in Human Keratinocytes and Up-Regulation of G2-M-phase Proteins

Human papillomavirus type 16 proteins E6 and E7 have been shown to cause centrosome amplification and lagging chromosomes during mitosis. These abnormalities during mitosis can result in missegregation of the chromosomes, leading to chromosomal instability. Genomic instability is thought to be an essential part of the conversion of a normal cell to a cancer cell. We now show that E6 and E7 together cause polyploidy in primary human keratinocytes soon after these genes are introduced into the cells. Polyploidy seems to result from a spindle checkpoint failure arising from abrogation of the normal functions of p53 and retinoblastoma family members by E6 and E7, respectively. In addition, E6 and E7 cause deregulation of cellular genes such as Plk1, Aurora-A, cdk1, and Nek2, which are known to control the G2-M-phase transition and the ordered progression through mitosis.

Neural network controlled three-phase four-wire shunt active powerfilter

A three-phase four-wire shunt active power filter for harmonic mitigation and reactive power compensation in power systems supplying nonlinear loads is presented. Three adaptive linear neurons are used to tackle the desired three-phase filter current templates. Another feedforward three-layer neural network is adopted to control the output filter compensating currents online. This is accomplished by producing the appropriate switching patterns of the converter's legs IGBTs. Adequate tracking of the filter current references is obtained by this method. The active filter injects the current required to compensate for the harmonic and reactive components of the line currents, Simulation results of the proposed active filter indicate a remarkable improvement in the source current waveforms. This is reflected in the enhancement of the unified power quality index defined. Also, the filter has exhibited quite a high dynamic response for step variations in the load current, assuring its potential for real-time applications

Universal power quality manager with a new control scheme

A new universal power quality manager is proposed. The proposal treats a number of power quality problems simultaneously. The universal manager comprises a combined series and shunt three-phase PWM controlled converters sharing a common DC link. A control scheme based on fuzzy logic is introduced and the general features of the design and operation processes are outlined. The performance of two configurations of the proposed power quality manager are compared in terms of a recently formulated unified power quality index. The validity and integrity of the proposed system is proved through computer simulated experiments

Space and phase resolved plasma parameters in an industrial dual-frequency capacitively coupled radio-frequency discharge

The dynamics of high energetic electrons (>= 11.7 eV) in a modified industrial confined dual-frequency capacitively coupled RF discharge (Exelan, Lam Research Inc.), operated at 1.937 MHz and 27.118 MHz, is investigated by means of phase resolved optical emission spectroscopy. Operating in a He-O-2. plasma with small rare gas admixtures the emission is measured, with one-dimensional spatial resolution along the discharge axis. Both the low and high frequency RF cycle are resolved. The diagnostic is based on time dependent measurements of the population densities of specifically chosen excited rare gas states. A time dependent model, based on rate equations, describes the dynamics of the population densities of these levels. Based on this model and the comparison of the excitation of various rare gas states, with different excitation thresholds, time and space resolved electron temperature, propagation velocity and qualitative electron density as well as electron energy distribution functions are determined. This information leads to a better understanding of the dual-frequency sheath dynamics and shows, that separate control of ion energy and electron density is limited.

Phase agile reflectarray cells based on liquid crystals

Experimental results at X-band are used to compare the electromagnetic scattering from a printed reflectarray cell, which is constructed on 500 mu m thick layers of three different nematic state liquid crystals. It is shown that a small voltage can be used to vary the permittivity of the tunable substrate and thereby control the phase of the reflected signals. Numerical results using Ansoft HFSS are compared with the measured phase, resonant frequencies and signal attenuation for two orientations of the liquid crystal molecules. Data fitting is employed to quantify the loss tangent and the permittivity values of the three anisotropic specimens. The performance trade-offs that are imposed by the use of commercially available materials are discussed, and the computer model is used to specify the electrical properties of a liquid crystal mixture, which can provide a signal loss of <1 dB and a dynamic phase range of 300 degrees from the patch elements at 10 GHz.

The influence of the relative phase between the driving voltages on electron heating in asymmetric dual frequency capacitive discharges

The influence of the relative phase between the driving voltages on electron heating in asymmetric phase-locked dual frequency capacitively coupled radio frequency plasmas operated at 2 and 14 MHz is investigated. The basis of the analysis is a nonlinear global model with the option to implement a relative phase between the two driving voltages. In recent publications it has been reported that nonlinear electron resonance heating can drastically enhance the power dissipation to electrons at moments of sheath collapse due to the self-excitation of nonlinear plasma series resonance (PSR) oscillations of the radio frequency current. This work shows that depending on the relative phase of the driving voltages, the total number and exact moments of sheath collapse can be influenced. In the case of two consecutive sheath collapses a substantial increase in dissipated power compared with the known increase due to a single PSR excitation event per period is observed. Phase resolved optical emission spectroscopy (PROES) provides access to the excitation dynamics in front of the driven electrode. Via PROES the propagation of beam-like energetic electrons immediately after the sheath collapse is observed. In this work we demonstrate that there is a close relation between moments of sheath collapse, and thus excitation of the PSR, and beam-like electron propagation. A comparison of simulation results to experiments in a single and dual frequency discharge shows good agreement. In particular the observed influence of the relative phase on the dynamics of a dual frequency discharge is described by means of the presented model. Additionally, the analysis demonstrates that the observed gain in dissipation is not accompanied by an increase in the electrode’s dc-bias voltage which directly addresses the issue of separate control of ion flux and ion energy in dual frequency capacitively coupled radio frequency plasmas.

Improved Direct Power Control of Grid Connected DC/AC Converters

This paper proposes new direct power control (DPC) strategies for three-phase DC/AC converters with improved dynamic response and steady-state performance. As with an electrical machine, source and converter flux which equal the integration of the respective source and converter voltage are used to define active and reactive power flow. Optimization of the look-up-table used in conventional DPC is outlined first, to improve the power control and reduce the current distortion. Then constant switching frequency DPC is developed where the required converter voltage vector within a fixed half switching period is calculated directly from the active and reactive power errors. Detailed angle compensation due to the finite sampling frequency and the use of integral controller to further improve the power control accuracy, are described. Both simulation and experimental results are used to compare conventional DPC and vector control, and to demonstrate the effectiveness and robustness of the proposed control strategies during active and reactive power steps, and line inductance variations.

A Phase Grating Approach to Modeling Surface Diffusion in FDTD Room Acoustics Simulations

In this paper, a method for modeling diffusive boundaries in finite difference time domain (FDTD) room acoustics simulations with the use of impedance filters is presented. The proposed technique is based on the concept of phase grating diffusers, and realized by designing boundary impedance filters from normal-incidence reflection filters with added delay. These added delays, that correspond to the diffuser well depths, are varied across the boundary surface, and implemented using Thiran allpass filters. The proposed method for simulating sound scattering is suitable for modeling high frequency diffusion caused by small variations in surface roughness and, more generally, diffusers characterized by narrow wells with infinitely thin separators. This concept is also applicable to other wave-based modeling techniques. The approach is validated by comparing numerical results for Schroeder diffusers to measured data. In addition, it is proposed that irregular surfaces are modeled by shaping them with Brownian noise, giving good control over the sound scattering properties of the simulated boundary through two parameters, namely the spectral density exponent and the maximum well depth.

Techniques for multiple-set synchronous islanding control

Power system islanding can improve the continuity of power supply. Synchronous islanded operation enables the islanded system to remain in phase with the main power system while not electrically connected, so avoiding out-of-synchronism re-closure. Specific consideration is required for the multiple-set scenario. In this paper a suitable island management system is proposed, with the emphasis being on maximum island flexibility by allowing passive islanding transitions to occur, facilitated by intelligent control. These transitions include: island detection, identification, fragmentation, merging and return-to-mains. It can be challenging to detect these transitions while maintaining syn-chronous islanded operation. The performance of this control system in the presence of a variable wind power in-feed is also examined. A Mathworks SimPowerSystems simulation is used to investigate the performance of the island management system. The benefit and requirements for energy storage, com-munications and distribution system protection for this application are considered.

Finite difference time domain modeling of phase grating diffusion

In this paper, a method for modeling diffusion caused by non-smooth boundary surfaces in simulations of room acoustics using finite difference time domain (FDTD) technique is investigated. The proposed approach adopts the well-known theory of phase grating diffusers to efficiently model sound scattering from rough surfaces. The variation of diffuser well-depths is attained by nesting allpass filters within the reflection filters from which the digital impedance filters used in the boundary implementation are obtained. The presented technique is appropriate for modeling diffusion at high frequencies caused by small surface roughness and generally diffusers that have narrow wells and infinitely thin separators. The diffusion coefficient was measured with numerical experiments for a range of fractional Brownian diffusers.

Cloning transformations in spin networks without external control

In this paper we present an approach to quantum cloning with unmodulated spin networks. The cloner is realized by a proper design of the network and a choice of the coupling between the qubits. We show that in the case of phase covariant cloner the XY coupling gives the best results. In the 1 -> 2 cloning we find that the value for the fidelity of the optimal cloner is achieved, and values comparable to the optimal ones in the general N -> M case can be attained. If a suitable set of network symmetries are satisfied, the output fidelity of the clones does not depend on the specific choice of the graph. We show that spin network cloning is robust against the presence of static imperfections. Moreover, in the presence of noise, it outperforms the conventional approach. In this case the fidelity exceeds the corresponding value obtained by quantum gates even for a very small amount of noise. Furthermore, we show how to use this method to clone qutrits and qudits. By means of the Heisenberg coupling it is also possible to implement the universal cloner although in this case the fidelity is 10% off that of the optimal cloner.