Walking strides direct rapid and flexible recruitment of visual circuits for course control in Drosophila.

Flexible mapping between activity in sensory systems and movement parameters is a hallmark of motor control. This flexibility depends on the continuous comparison of short-term postural dynamics and the longer-term goals of an animal, thereby necessitating neural mechanisms that can operate across multiple timescales. To understand how such body-brain interactions emerge across timescales to control movement, we performed whole-cell patch recordings from visual neurons involved in course control in Drosophila. We show that the activity of leg mechanosensory cells, propagating via specific ascending neurons, is critical for stride-by-stride steering adjustments driven by the visual circuit, and, at longer timescales, it provides information about the moving body's state to flexibly recruit the visual circuit for course control. Thus, our findings demonstrate the presence of an elegant stride-based mechanism operating at multiple timescales for context-dependent course control. We propose that this mechanism functions as a general basis for the adaptive control of locomotion.

Adsorption Behavior of Curcumin onto Cetyltrimethylammonium Chloride Reverse Micelles Immobilized on a Glass Surface As Studied by Polarized Visible Attenuated Total Reflection Spectrometry with a Glass Slab Optical Waveguide.

Polarized visible attenuated total reflection spectrometry with a glass slab optical waveguide revealed that when a hydrophobic dye, curcumin, was adsorbed onto the cetyltrimethylammonium chloride (CTAC) reverse micelles immobilized on a glass surface, in an undissociated form, the curcumin was perpendicular to the surface plane, while in a dissociated form, the curcumin was parallel to the plane. This implies that the former may be located in the CTAC monolayer while the latter may be located in the reverse micellar water phase immobilized on the plane.

Flow-Injection Chemiluminescence Method for Sensitive Determination of Ascorbic Acid in Fruit Juices and Pharmaceutical Samples Using a Luminol-Cetyltrimethylammonium Chloride Reversed Micelle System.

A highly sensitive flow-injection (FI) method was developed for the determination of ascorbic acid using chemiluminescence (CL) based detection. This method involved the following processes: (1) reduction of tetrachloroaurate(III) in hydrochloric acid with ascorbic acid; (2) on-line extraction of the residual Au(III) with rhodamine B from the aqueous hydrochloric acid solution into toluene, followed by the separation of the Au(III)-containing organic phase from the aqueous phase through a microporous Teflon membrane in the flow system; and (3) the measurement of CL produced in a flow cell upon mixing of the extract stream of Au(III) in toluene with luminol in the reversed micellar medium of cetyltrimethylammonium chloride-water in 1-hexanol-cyclohexane, which was injected into a CL reagent stream. In this procedure, a reduction in the CL intensity occurred due to the addition of ascorbic acid to the Au(III) solution. The CL signal of Au(III) decreased with increasing concentration of ascorbic acid in the aqueous sample solution. The proposed procedure allowed the indirect quantitative determination of ascorbic acid in the range of 1.0 × 10-12 to 1.0 × 10-7 M with a correlation coefficient of 0.987 and relative standard deviation of 2.1% (n = 6) at 1.0 × 10-9 M. The proposed FI-CL methodology was successfully applied for quantitative determination of ascorbic acid in fruit juices and pharmaceutical samples.

A faithful internal representation of walking movements in the Drosophila visual system.

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.

Near-infrared Laser-induced Temperature Elevation in Optically-trapped Aqueous Droplets in Air.

Near-infrared laser-induced temperature elevation in single aqueous ammonium sulfate droplets levitated in air were evaluated by means of laser trapping and Raman spectroscopy. Since the vapor pressure in an aqueous solution droplet should be thermodynamically in equilibrium with that of water in air, the equilibrium size of the droplet varies sensitively through evaporation/condensation of water in accordance with the temperature change of the droplet. In this study, we demonstrated that the changes in the size of an optically levitated aqueous ammonium sulfate droplet were induced by irradiation of a 1064-nm laser beam as a heat source under an optical microscope. Temperature elevation in the droplet was evaluated successfully by means of Raman spectroscopy, and the values determined were shown to be in good agreement with those by the theoretical calculations based on the absorption coefficient of water at 1064-nm and the thermal conductivity of air. To the best of our knowledge, this is the first experimental demonstration showing that the absorption coefficient evaluated from changes in the size of optically-trapped aqueous droplets is consistent with that of pure water.

A Flow Method for Chemiluminescence Determination of Antimony(III) and Antimony(V) Using a Rhodamine B-Cetyltrimethylammonium Chloride Reversed Micelle System Following On-Line Extraction.

A rapid and sensitive flow method, based on the combination of on-line solvent extraction with reversed micellar mediated chemiluminescence (CL) detection using rhodamine B (RB), was developed for the determination of antimony(III) and antimony(V) in aqueous samples. The on-line extraction procedure involved ion-pair formation of the antimony(V) chloro-complex anion with the protonated RBH(+) ion and its extraction from an aqueous hydrochloric acid solution into toluene, followed by phase separation using a microporous membrane. When in a flow cell of a detector, the ion-pair in the extract driven was mixed with the reversed micellar solution of cetyltrimethylammonium chloride in 1-hexanol-cyclohexane/water (0.60 mol dm(-3) H2SO4) containing cerium(IV), its uptake by the reversed micelles and the subsequent CL oxidation of RB with Ce(IV) occurred easily, then the produced CL signal was measured. Using the proposed flow method under the optimized experimental conditions, a detection limit (DL) of 0.35 µmol dm(-3) and a linear calibration graph with a dynamic range from DL to 16 µmol dm(-3) were obtained for Sb(V) with a precision of 1.4% relative standard deviation (n = 5) at the Sb(V) concentration of 8.2 µmol dm(-3). The present method was successfully applied to the determination of Sb(V) in water samples and to the differential determination of Sb(III) and Sb(V) in copper electrolyte industrial samples, where total antimony Sb(III) + Sb(V) was determined after oxidation of Sb(III) to Sb(V) with Ce(IV) and Sb(III) was calculated by difference, for which the DL was almost the same as that for Sb(V).

Spectrometric estimation of sample amount in aliquot for a direct solid sampling system and its application to the determination of trace impurities in silver nanoparticles by ETV-ICP-OES.

A method based on a tungsten boat furnace vaporiser, tungsten sample cuvettes, and an inductively coupled plasma (ICP) optical emission spectrometer has been developed for the direct determination of silicon, phosphorus, and sulphur in silver nanoparticles. The important point in the proposed method is that the entire sample in each batch is vaporised, which enables simultaneous measurement of the emission of not only the analyte but also the silver matrix. Furthermore, since the silver nanoparticles are sufficiently pure, the contribution of impurities to the sample amounts will be negligible. Therefore, this estimation is suitable for measuring the sample amount in each aliquot instead of the conventional weighing procedure using a microbalance; therefore, no tedious weighing procedures for estimating the sample amount introduced into the ETV device are needed. An additional advantage is that pretreatment and/or predigestion are unnecessary. The sample throughput is approximately 35 batches per hour. The detection limits of silicon, phosphorus, and sulphur in the silver nanoparticles (dry powder) are 15, 4.2, and 62 µg g(-1), respectively. Analytical results for various silver nanoparticles as both dry particles and in suspended solutions are described, and these values are compared to those obtained by conventional weighing with a microbalance. This methodology is useful for rapid screening and accurate analysis of silver nanoparticles, especially for industrial applications.

A flow method based on solvent extraction coupled on-line to a reversed micellar mediated chemiluminescence detection for selective determination of gold(III) and gallium(III) in water and industrial samples.

A rapid and sensitive flow method, based on the combination of on-line solvent extraction with reversed micellar mediated chemiluminescence (CL) detection using rhodamine B (RB), was investigated for the selective determination of Au(III) and Ga(III) in aqueous solutions. 2.0 M HCl was the optimum for extracting Au(III) while a 5.0M HCl solution containing 2.5M LiCl was selected as an optimum acidic medium for extraction of Ga(III). The Au(III) and Ga(III) chloro-complex anions were extracted from the above aqueous acidic solutions into toluene as their ion-pair complexes with the protonated RBH(+) ion followed by membrane phase separation in a flow system. In a flow cell of a detector, the extract was mixed with the reversed micellar solution of cetyltrimethylammonium chloride (CTAC) in 1-hexanol-cyclohexane/water (1.0M HCl) containing 0.10 M cerium(IV) and 0.05 M lithium sulfate. Then uptake of the ion-pair by the CTAC reversed micelles and the subsequent CL oxidation of RB with Ce(IV) occurred easily and the CL signals produced were recorded. Using a flow injection system, a detection limit (DL) of 0.4 µM Au(III) and 0.6 µM Ga(III), and linear calibration graphs with dynamic ranges from the respective DLs to 10 µM for Au(III) and Ga(III) were obtained under the optimized experimental conditions. The relative standard deviations (n=6) obtained at 2.0 µM Au(III) and 4.0 µM Ga(III) were 3.0% and 2.4%, respectively. The presented CL methodology has been applied for the determination of Au(III) and Ga(III) in water and industrial samples with satisfactory results.

Direct solid sampling system for electrothermal vaporization and its application to the determination of chlorine in nanopowder samples by inductively coupled plasma optical emission spectroscopy.

An electrothermal vaporization (ETV) system using a tungsten boat furnace (TBF) sample cuvette was designed for the direct determination of chlorine in metallic nanopowders and fine powder samples with detection by inductively coupled plasma optical emission spectroscopy (ICP-OES). A portion of a powder or particle sample was placed into a small tungsten sample cuvette and weighed accurately. A modifier solution of aqueous or alcoholic potassium hydroxide was added to it. Then, the cuvette was positioned on the TBF incorporated into the ETV apparatus. The analyte was vaporized and introduced into the ICP optical emission spectrometer with a carrier gas stream of argon and hydrogen. The metal samples were analyzed by using an external calibration curve prepared from aqueous standard solutions. Few chemical species including analyte and some chlorine-free species were introduced into the ICP, because the analyte has been separated from the matrix before introduction. Under such dry plasma conditions, the energy of plasma discharge was focused on the excitation of chlorine atoms, and as a result, lower detection limits were achieved. A detection limit of 170 ng g(-1) of chlorine in solid metal samples was established when 60 mg sample was used. The relative standard deviation for 16 replicate measurements obtained with 100 ng chlorine was 8.7%. Approximately 30 batches could be vaporized per hour. The analytical results for various nanopowders (iron (III) oxide, copper, silver, and gold) and metallic fine powder samples (silver and gold) are described.

Odorant concentration differentiator for intermittent olfactory signals.

Animals need to discriminate differences in spatiotemporally distributed sensory signals in terms of quality as well as quantity for generating adaptive behavior. Olfactory signals characterized by odor identity and concentration are intermittently distributed in the environment. From these intervals of stimulation, animals process odorant concentration to localize partners or food sources. Although concentration-response characteristics in olfactory neurons have traditionally been investigated using single stimulus pulses, their behavior under intermittent stimulus regimens remains largely elusive. Using the silkmoth (Bombyx mori) pheromone processing system, a simple and behaviorally well-defined model for olfaction, we investigated the neuronal representation of odorant concentration upon intermittent stimulation in the naturally occurring range. To the first stimulus in a series, the responses of antennal lobe (AL) projection neurons (PNs) showed a concentration dependence as previously shown in many olfactory systems. However, PN response amplitudes dynamically changed upon exposure to intermittent stimuli of the same odorant concentration and settled to a constant, largely concentration-independent level. As a result, PN responses emphasized odorant concentration changes rather than encoding absolute concentration in pulse trains of stimuli. Olfactory receptor neurons did not contribute to this response transformation which was due to long-lasting inhibition affecting PNs in the AL. Simulations confirmed that inhibition also provides advantages when stimuli have naturalistic properties. The primary olfactory center thus functions as an odorant concentration differentiator to efficiently detect concentration changes, thereby improving odorant source orientation over a wide concentration range.

Postsynaptic odorant concentration dependent inhibition controls temporal properties of spike responses of projection neurons in the moth antennal lobe.

Although odorant concentration-response characteristics of olfactory neurons have been widely investigated in a variety of animal species, the effect of odorant concentration on neural processing at circuit level is still poorly understood. Using calcium imaging in the silkmoth (Bombyx mori) pheromone processing circuit of the antennal lobe (AL), we studied the effect of odorant concentration on second-order projection neuron (PN) responses. While PN calcium responses of dendrites showed monotonic increases with odorant concentration, calcium responses of somata showed decreased responses at higher odorant concentrations due to postsynaptic inhibition. Simultaneous calcium imaging and electrophysiology revealed that calcium responses of PN somata but not dendrites reflect spiking activity. Inhibition shortened spike response duration rather than decreasing peak instantaneous spike frequency (ISF). Local interneurons (LNs) that were specifically activated at high odorant concentrations at which PN responses were suppressed are the putative source of inhibition. Our results imply the existence of an intraglomerular mechanism that preserves time resolution in olfactory processing over a wide odorant concentration range.

Surface tension determination through measurements of resonance oscillation of a small surface using dielectric force by a localized alternating current electric field.

The present study proposed a novel microscope method for the determination of the surface tension of liquids through measurements of the forced oscillation of the small surface, which was induced with a rod electrode by applying an alternating current (ac) voltage. The electrode bottom was placed 200 µm above the surface, and a stronger electric field was generated under it. Liquids of a larger dielectric constant than air gathered under the electrode by a dielectric force, and thus the surface was oscillated. The oscillation was successfully analyzed with the forced oscillation model and the oscillation mode of two-dimensional circular membranes. A resonance oscillation was observed, the frequency of which was well related to the ratio of surface tension to density of the liquids. Therefore, the proposed novel method can be used for the determination of surface tensions of small surfaces with known densities.

Flow chemiluminescence determination of antimony(III,V) using a rhodamine B-cetyltrimethylammonium chloride reversed micelle system following liquid-liquid extraction.

A flow chemiluminescence (CL) method combined with a liquid-liquid extraction technique is proposed for the indirect determination of antimony in aqueous samples using rhodamine B (RB). In the liquid-liquid extraction process, the antimony(V) chloro-complex anion, [SbCl(6)](-), was extracted from an aqueous acidic solution into toluene via ion-pair formation with the protonated RBH(+) ion. Upon mixing the extract with a reversed micellar reagent solution of cetyltrimethylammonium chloride (CTAC) in 1-hexanol-cyclohexane/water (0.60 mol dm(-3) H(2)SO(4)) containing cerium(IV), uptake of the ion-pair by CTAC reversed micelles occurred easily, followed by an oxidation reaction of RB with Ce(IV) in the CL process. The CL signal produced was then measured. Using a flow injection system, the detection limits (DL) of 0.25 µmol dm(-3) Sb(III) and 0.20 µmol dm(-3) Sb(V), and linear calibration graphs with dynamic ranges from the respective DLs to 16 µmol dm(-3) for Sb(III) and Sb(V) were obtained under optimized experimental conditions. The proposed method was successfully applied to a mixture of Sb(III) and Sb(V), where total antimony, Sb(III) + Sb(V), was measured using ceric sulfate as an oxidant to oxidize Sb(III) to Sb(V) prior to extraction, Sb(V) was determined directly without the use of an oxidant, and Sb(III) was calculated by difference.

Microscope measurements for the transient formation of W/O emulsions of sodium bis(2-ethylhexyl) sulfosuccinate in the dodecane/water interfacial region.

The present study investigated the transient formation of water-in-oil (W/O) emulsions of sodium bis(2-ethylhexyl) sulfosuccinate (aerosol OT, AOT) in a dodecane/water interfacial region and the anomalous uptake of water in the dodecane phase by in situ bright-field optical microscopy and water concentration measurements in detail. The hydrodynamic radius of the individual W/O emulsions in the dodecane phase was determined to be 0.1-1.2 µm from the analysis of their diffusion behavior; they are much larger than common W/O microemulsions (a few nanometers in radius). At first, they were formed spontaneously in the dodecane/water interfacial region without shaking, and they diffused away into the dodecane phase. Then, almost all of them vanished at the interface by fusion. Their number and the water concentration in the dodecane phase increased first and then decreased gradually. The formation mechanism was discussed with estimated concentration profiles of AOT and water molecules, which suggests that larger W/O emulsions of 0.01-0.44 µm in radius can be formed in the dodecane phase near the interface (within 2 µm) because the concentration of AOT becomes lower than that of water there.

Chemiluminescence from an oxidation reaction of rhodamine B with cerium(IV) in a reversed micellar medium of cetyltrimethylammonium chloride in 1-hexanol-cyclohexane/water.

The chemiluminescence (CL) emission, observed when rhodamine B (RB) in 1-hexanol-cyclohexane was mixed with cerium(IV) sulfate in sulfuric acid dispersed in a reversed micellar medium of cetyltrimethylammonium chloride (CTAC) in 1-hexanol-cyclohexane/water, was investigated using a flow-injection system. The CL emission from the oxidation reaction of RB with Ce(IV) was found to be stronger in the CTAC reversed micellar solution compared with an aqueous solution. Bearing on the enhancement effect of the CTAC reverse micelles on the RB-Ce(IV) CL, several studies including stopped-flow, fluorescence and electron spin resonance (ESR) spectrometries were performed. Rapid spectral changes of an intermediate in the RB-Ce(IV) reaction in the aqueous and reversed micellar solutions were successfully observed using a stopped-flow method. The effect of the experimental variables, i.e., oxidant concentration, sulfuric acid concentration, the mole fraction of 1-hexanol, water-to-surfactant molar concentration ratio, flow rate, upon the CL intensity was evaluated. Under the experimental conditions optimized for a flow-injection determination of RB based on the new reversed micellar-mediated CL reaction with Ce(IV), a detection limit of 0.08 µmol dm(-3) RB was achieved, and a linear calibration graph was obtained with a dynamic range from 0.5 to 20 µmol dm(-3). The relative standard deviation (n = 6) obtained at an RB concentration of 3 µmol dm(-3) was 3%.

Acid-base behavior of rhodamine B in a reversed micellar medium of cetyltrimethylammonium chloride in 1-hexanol-cyclohexane/water.

The acid-base behavior of rhodamine B (RB) in reversed micellar solutions of cetyltrimethylammonium chloride (CTAC) in 1-hexanol-cyclohexane/water was investigated through absorption and fluorescence measurements under varying the hydrogen-ion concentration in a water pool, the mole fraction of 1-hexanol in a bulk solvent and the water to surfactant molar concentration ratio. RB exhibited equilibria between the cationic, zwitterion and lactone forms of the dye as a cause of the spectral changes, indicating a change in the RB distribution among the reversed micellar water pool, interface and bulk solvent. Furthermore, RB was used as a probe to develop a method for determining the critical micelle concentration (CMC) in CTAC solutions. Abrupt variations in the intensities and wavelengths of the absorption and emission maxima of RB were observed at the CMC. The standard free energy of micellization was also evaluated from the CMC data.

Nicardipine vs. saline injection as treatment for Peyronie's disease: a prospective, randomized, single-blind trial.

INTRODUCTION: Various conservative treatments for Peyronie's disease (PD) have been attempted over the years. Intralesional verapamil injection has been tested in prospective randomized studies, but the effect of this treatment seems insufficient. Nicardipine is a calcium antagonist alternative to verapamil and is reportedly more effective in vitro. AIM: The objective of our study was to evaluate the usefulness of intralesional nicardipine injection as a conservative treatment for PD in the transition period of acute and chronic phase. METHODS: Eighty-six patients (age: 38-72 years, mean: 52) were enrolled in this study. A total of 74 patients were assigned randomly to nicardipine group (10 mg diluted in 10 mL of distilled water daily, N=37) and control group (10 mL of saline water, N=37). A total of six injections were administrated biweekly. MEAN OUTCOME MEASURE: The subjects were assessed by International Index of Erectile Function (IIEF)-5 and international pain scale. The plaque size was measured by ultrasonography after 20 µg intracavernosal injection of alprostadil (prostaglandin E1). The penile curvature was also measured by taking a photograph at maximum rigidity. RESULTS: A reduction of pain score was seen throughout the course of treatment in both groups with a significant difference between the nicardipine and control groups (multiple analysis of variance test, P=0.019). A significant improvement of IIEF-5 score occurred only in the nicardipine group at 48 weeks after the initiation of treatment (P<0.01). The plaque size was significantly reduced at 48 weeks only in the nicardipine group (12 points, P=0.0004 by paired t-test). The penile curvature was significantly improved in both groups (P<0.01) without significant difference between them (P=0.14). There were no severe side effects, such as hypotension or other cardiovascular events. CONCLUSION: Our findings indicate that intralesional nicardipine injection is clinically effective as a conservative treatment for PD in the transition period of acute and chronic phase.

Direct determination of bromine in plastics by electrothermal vaporization/inductively coupled plasma mass spectrometry using a tungsten boat furnace vaporizer and an exchangeable sample cuvette system.

A tungsten boat furnace vaporization inductively coupled plasma mass spectrometry (TBF/ICP-MS) method has been applied to the direct determination of bromine in plastic samples. In the pretreatment, the plastic sample is spread over a small sample cuvette made of tungsten by treating it with a strongly basic organic solution, e.g., octanol or diisobutyl ketone in the presence of potassium hydroxide. The cuvette is placed on a tungsten boat furnace, with which the electrothermal vaporizer is equipped. At the vaporization step, a widely spread thin layer of the sample facilitates its efficient evaporation and introduction into an ICP mass spectrometer. The most remarkable feature is that all the bromine species in plastic samples are decomposed to form a thermally stable inorganic salt during the pretreatment procedure. Therefore, the bromine content in plastic samples can be measured by a calibration curve method constructed with an aqueous standard solution of potassium bromate(V). The detection limit (3sigma) was estimated to be 0.77 pg of bromine, which corresponds to a concentration of 0.31 ng g(-1) of bromine in plastic samples when a sample amount taken of 2.5 mg is studied. The relative standard deviation was calculated to be 2.2%. Analytical results of some plastic samples, which contained both inorganic bromide salts and also organic bromine species, are given.

In situ measurements of emission transition dipole moment of individual ordered microdomain of diprotonated tetraphenylporphine aggregate formed at dodecane/aqueous H2SO4 interface.

Rhombic-ordered microdomains of diprotonated 5,10,15,20-tetraphenylporphine aggregate, whose sizes were 10-200 microm, were formed at dodecane/aqueous H(2)SO(4) interfaces. The light excitation of their two absorption bands (410 and 473 nm for H- and J-bands, respectively) led to one fluorescence band at longer wavelength (723 nm). The direction of the emission transition dipole moment (mu(e)) of individual rhombic microdomains, determined with an in situ optical microscope and a linear polarizer, was almost parallel to the major axis, which was also almost parallel to the direction of the absorption transition dipole moment of their J-bands. Their absorption and emission transition scheme was proposed.