Microsecond pulsed glow discharge as an analytical spectroscopic source

A pulsed glow discharge, operating in the microsecond regime, has been found to be advantageous for the examination of solid samples. We have studied the spectroscopic response by atomic emission, absorption, fluorescence, and mass spectrometries. Results to date show enhanced efficiency for analytical response of the sputtered sample atoms. This type of discharge also permits acquisition of useful diagnostic information concerning glow discharge processes.     

Adjustable Voltage and Frequency Polyphase Sine Wave Signal Generator

An adjustable-voltage adjustable-frequency polyphase reversible-phase sequence sine wave signal generator is described. This signal generator develops the reference waveforms, in this case sine waves, that are required in the control circuits of certain types of static dc to ac inverters and ac to ac cycloconverters. Digital and linear integrated circuits together with passive components are used to generrate the output signals. The output frequency is adjustable from 0 to 500 hertz; the output voltage is adjustable from 0 to 20 volts peak-to-peak. The phase sequence is reversible on command. The theory of operation together with steady-state and transient performance data are presented.     

Bioavailability Studies and in vitro Profiling of the Selective Excitatory Amino Acid Transporter Subtype 1 (EAAT1) Inhibitor UCPH‐102

Although the selective excitatory amino acid transporter subtype 1 (EAAT1) inhibitor UCPH‐101 has become a standard pharmacological tool compound for in vitro and ex vivo studies in the EAAT research field, its inability to penetrate the blood–brain barrier makes it unsuitable for in vivo studies. In the present study, per os (p.o.) administration (40 mg kg^?1) of the closely related analogue UCPH‐102 in rats yielded respective plasma and brain concentrations of 10.5 and 6.67 μm after 1 h. Three analogue series were designed and synthesized to improve the bioavailability profile of UCPH‐102, but none displayed substantially improved properties in this respect. In vitro profiling of UCPH‐102 (10 μm ) at 51 central nervous system targets in radioligand binding assays strongly suggests that the compound is completely selective for EAAT1. Finally, in a rodent locomotor model, p.o. administration of UCPH‐102 (20 mg kg^?1) did not induce acute effects or any visible changes in behavior.     

Lamotrigine may limit pathological excitation in the hippocampus by modulating a transient potassium outward current

Actions of the new antiepileptic drug lamotrigine were characterised using whole cell patch clamp recordings from rat CA1 pyramidal cells in vitro. The results suggest that lamotrigine, besides its previously described effect on the fast sodium inward current and calcium currents, modulates the transient potassium outward current ID. This may be an effective mechanism to inhibit pathological excitation.     

Calcium antagonistic actions of drugs used in treatment of affective disorders

Disturbances of intra- and extracellular calcium levels are often reported during the course of affective disorders. In this review calcium antagonistic properties of drugs used in the treatment of affective disorders are discussed. The effects of calcium channel blockers in animal models of depression and in clinical trials are compared to established treatment strategies. Knowledge on changes in calcium homoeostasis during the treatment of affective disorders may increase the scope of therapeutic options.     

Noise reduction in directional signals using multiple morse wavelets illustrated on quadrature Doppler ultrasound

The use of multiple complex-valued Morse wavelets for the scalogram study of signals which are unidirectional at any time, but are bidirectional overall is considered. These wavelets are well-suited to identifying the forward and reverse components. Scalogram averaging which is possible due to the multiplicity of the complex-valued wavelets leads to a scalogram with reduced noise. Information from positive and negative scales can then be used to estimate a final "cleaned" scalogram. Quadrature Doppler ultrasound blood flow in the femoral artery is taken as an example to clearly illustrate the noise reduction.     

A Variance Equality Test for Two Correlated Complex Gaussian Variables With Application to Spectral Power Comparison

Complex-valued Gaussian distributions occur frequently in signal processing. We derive a simple statistic, independent of any complex-valued correlation, for testing for the equality of variances using a sample drawn from such a bivariate distribution. The percentage points of the distribution are easy to compute. The power of the test is determined and shown to be high even for very small sample sizes when the variables are highly correlated. The new test is used to determine whether the spectral power associated with an ultralow-frequency wave in the solar magnetic field is equal at two different observing spacecraft