The integration of sensorimotor signals to internally estimate self-movement is critical for spatial perception and motor control. However, which neural circuits accurately track body motion and how these circuits control movement remain unknown. We found that a population of Drosophila neurons that were sensitive to visual flow patterns typically generated during locomotion, the horizontal system (HS) cells, encoded unambiguous quantitative information about the fly's walking behavior independently of vision. Angular and translational velocity signals were integrated with a behavioral-state signal and generated direction-selective and speed-sensitive graded changes in the membrane potential of these non-spiking cells. The nonvisual direction selectivity of HS cells cooperated with their visual selectivity only when the visual input matched that expected from the fly's movements, thereby revealing a circuit for internally monitoring voluntary walking. Furthermore, given that HS cells promoted leg-based turning, the activity of these cells could be used to control forward walking.

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Upon mixing of tris(8-quinolinolato)iron(III), an enhancement in the chemiluminescence emission resulting from the luminol-hydrogen peroxide reaction in reversed micellar solution was observed. Uptake of the complex by reverse micelles and its subsequent decomposition in the micelles appear to occur easily in the process.

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A new method, based on the direct combination of solvent extraction with luminol chemiluminescence (CL) In a reversed micellar system of cetyltrimethylammonlum chloride-water (buffered with sodium carbonate)-6:5 (v/v) chloroformcyclohexane, Is established for the determination of gold In aqueous solutions. The Interference behavior of 15 metals on the reference gold CL signals was evaluated. By dispersing an aqueous solution of the Individual Interferent alone and In admixture with the analyte, a comparative Inquiry on their CL behavior was also carried out In the reversed micellar medium. Separation of analyte from Interferents by extraction with trln-octylphosphlne oxide In chloroform resulted In reduced or no Interference. The present method was applied to the determination of gold In Industrial samples of silver-based alloy.This work was partially supported by a Grant-in-Aid for Scientific Research, No. 04453038, from the Ministry of Education, Science, and Culture, Japan, and one of the authors, Imdadullah, also thanks this Ministry for awarding a Scholarship. We thank the Analytical Center of Sumitomo Metal Mining Co., Ltd., Niihama, Japan, for providing us silver-based alloy samples.

A fast and sensitive method for the determination of atropine, an alkaloid closely related to cocaine, is proposed. The principles of on-line ion-pair formation of alkaloid-metal complexes and liquid-liquid extraction are applied to the chemiluminescence determination of atropine. On mixing with a reversed micellar medium of cetyltrimethylammonium chloride in dichloromethane-cyclohexane (1:1 v/v)-water (0.3 M Na2CO3) containing luminol, the ion-pair complex of tetrachloroaurate(III) with atropinium produced an analytical chemiluminescence signal when it entered the reversed micellar water pool. Using the reverse-flow injection and chemical conditions optimized for atropine in aqueous samples, a detection limit of 1 ng/mL was achieved and a linear calibration graph was obtained with a wide dynamic range from 10 ng/mL to 100 micrograms/mL. The proposed method is simple and provides a good precision with a relative standard deviation (n = 6) of ca. 3% at the atropine concentration of 100 ng/mL. After a preliminary study involving the potential interference from species of organic, inorganic, and metallic nature, the method was applied to the determination of atropine in artificial urine samples and of atropine and scopolamine in pharmaceutical formulations.

The chemiluminescence (CL) reaction of tetrachloroaurate-(III) with luminol In reversed micellar system of hexadecyltrlmethylammonlum chloride-water (buffered with sodium carbonate)-6:S (v/v) chloroform-cyclohexane was studied and applied to develop a new flow Injection procedure for the determination of gold at trace levels In chloroform.The behavior of the gold(III) complex was examined by Its spectral measurements In the near-UV and visible regions In dWferent media. All the optimization conditions for the method were determined by using a flow system, and the characteristics of the CL system In the reverse micelles were examined. The method Is simple and reproducible with a detection limit (DL) of 10 pg mL"1. The calibration graph was linear between 1 ng mL"1 and 1000 ng mL'1 along with a second straight Une from the DL up to 1 ng mL"1. The relative standard deviation was 3%.