WorldWideScience

Sample records for evoked transmitter release

  1. Effects of Anemonia sulcata toxin II on presynaptic currents and evoked transmitter release at neuromuscular junctions of the mouse.

    Science.gov (United States)

    Molgó, J; Mallart, A

    1985-12-01

    The effect of Anemonia sulcata toxin II (ATX-II) on the amount of transmitter released by nerve impulses was investigated in motor end-plates of the mouse. ATX-II (80 nM) caused repetitive end-plate potentials in response to a single nerve stimulus and a 3- to 4-fold increase in the quantal content of the phasic end-plate potential. This increase is less than what would be expected if ATX-II induced plateau action potentials at the motor endings. To solve this discrepancy presynaptic currents were recorded by focal extracellular electrodes. It was found that the K current present at the endings is strong enough to prevent the development of presynaptic plateau action potentials, in contrast to what has been observed in other excitable membranes (unmyelinated axons, nodes of Ranvier and skeletal muscle fibres). By using tetraethylammonium and 3,4-diaminopyridine to block K channels and Co2+ to block Ca channels, ATX-II allowed the development of prolonged plateau responses at the endings upon motor nerve stimulation. These results suggest that the mouse motor endings are endowed with a relatively powerful K channel system, which effectively controls the amount of presynaptic depolarization.

  2. Development of two transmitter release components during the critical period for imprinting in the chick IMHV.

    Science.gov (United States)

    Kiyosue, Kazuyuki; Shimabayashi, Eiko; Taguchi, Takahisa

    2002-10-01

    Transmitter release at an excitatory synapse has two components, fast synchronous and slow asynchronous transmitter release. Using the whole cell recording technique, we investigated the developmental properties of neurotransmitter release, which is composed of the two components in the intermediate and medial part of the hyperstriatum ventral (IMHV) of chicks during the critical period for imprinting. Analysis of the paired-pulse responses revealed that the depression of the excitatory postsynaptic currents (EPSCs), driven mainly by fast synchronous release, was frequently observed in P0-1 chicks but not in those at P5-8. The spontaneous excitatory postsynaptic currents (sEPSCs) after the paired-pulse stimulation, which were thought to be driven by asynchronous transmitter releases, were observed more frequently in P0-1 chicks than P5-8 chicks. Furthermore, examination of Ca2+ dependency in the evoked EPSCs showed that the amplitudes in P5-8 chicks were more sensitive to reduction of the extracellular Ca2+ concentration than younger chicks. Considering that the Ca2+ dependency of EPSCs is defined by both Ca2+ sensitivity and the proportion of each type of release machineries at the release site, these results indicate that the ratio of fast synchronous to slow asynchronous transmitter release machinery changed during the critical period. These changes may play critical roles in the capacity of the avian brain to consolidate novel experience in the immediate period after hatching.

  3. Presynaptic membrane potential affects transmitter release in an identified neuron in Aplysia by modulating the Ca2+ and K+ currents

    Science.gov (United States)

    Shapiro, Eli; Castellucci, Vincent F.; Kandel, Eric R.

    1980-01-01

    We have examined the relationships between the modulation of transmitter release and of specific ionic currents by membrane potential in the cholinergic interneuron L10 of the abdominal ganglion of Aplysia californica. The presynaptic cell body was voltage-clamped under various pharmacological conditions and transmitter release from the terminals was assayed simultaneously by recording the synaptic potentials in the postsynaptic cell. When cell L10 was voltage-clamped from a holding potential of -60 mV in the presence of tetrodotoxin, graded transmitter release was evoked by depolarizing command pulses in the membrane voltage range (-35 mV to + 10 mV) in which the Ca2+ current was also increasing. Depolarizing the holding potential of L10 results in increased transmitter output. Two ionic mechanisms contribute to this form of plasticity. First, depolarization inactivates some K+ channels so that depolarizing command pulses recruit a smaller K+ current. In unclamped cells the decreased K+ conductance causes spike-broadening and increased influx of Ca2+ during each spike. Second, small depolarizations around resting potential (-55 mV to -35 mV) activate a steady-state Ca2+ current that also contributes to the modulation of transmitter release, because, even with most presynaptic K+ currents blocked pharmacologically, depolarizing the holding potential still increases transmitter release. In contrast to the steady-state Ca2+ current, the transient inward Ca2+ current evoked by depolarizing clamp steps is relatively unchanged from various holding potentials. PMID:6244571

  4. Release of chemical transmitters from cell bodies and dendrites of nerve cells.

    Science.gov (United States)

    De-Miguel, Francisco F; Nicholls, John G

    2015-07-05

    Papers in this issue concern extrasynaptic transmission, namely release of signalling molecules by exocytosis or diffusion from neuronal cell bodies, dendrites, axons and glia. Problems discussed concern the molecules, their secretion and importance for normal function and disease. Molecules secreted extrasynaptically include transmitters, peptides, hormones and nitric oxide. For extrasynaptic secretion, trains of action potentials are required, and the time course of release is slower than at synapses. Questions arise concerning the mechanism of extrasynaptic secretion: how does it differ from the release observed at synaptic terminals and gland cells? What kinds of vesicles take part? Is release accomplished through calcium entry, SNAP and SNARE proteins? A clear difference is in the role of molecules released synaptically and extrasynaptically. After extrasynaptic release, molecules reach distant as well as nearby cells, and thereby produce long-lasting changes over large volumes of brain. Such changes can affect circuits for motor performance and mood states. An example with clinical relevance is dyskinesia of patients treated with l-DOPA for Parkinson's disease. Extrasynaptically released transmitters also evoke responses in glial cells, which in turn release molecules that cause local vasodilatation and enhanced circulation in regions of the brain that are active. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  5. Dopamine neurons release transmitter via a flickering fusion pore.

    Science.gov (United States)

    Staal, Roland G W; Mosharov, Eugene V; Sulzer, David

    2004-04-01

    A key question in understanding mechanisms of neurotransmitter release is whether the fusion pore of a synaptic vesicle regulates the amount of transmitter released during exocytosis. We measured dopamine release from small synaptic vesicles of rat cultured ventral midbrain neurons using carbon fiber amperometry. Our data indicate that small synaptic vesicle fusion pores flicker either once or multiple times in rapid succession, with each flicker releasing approximately 25-30% of vesicular dopamine. The incidence of events with multiple flickers was reciprocally regulated by phorbol esters and staurosporine. Thus, dopamine neurons regulate the amount of neurotransmitter released by small synaptic vesicles by controlling the number of fusion pore flickers per exocytotic event. This mode of exocytosis is a potential mechanism whereby neurons can rapidly reuse vesicles without undergoing the comparatively slow process of recycling.

  6. Amiodarone reduces depolarization-evoked glutamate release from hippocampual synaptosomes

    Directory of Open Access Journals (Sweden)

    Chia Yu Chang

    2017-03-01

    Full Text Available Decreased brain glutamate level has emerged as a new therapeutic approach for epilepsy. This study investigated the effect and mechanism of amiodarone, an anti-arrhythmic drug with antiepileptic activity, on glutamate release in the rat hippocampus. In a synaptosomal preparation, amiodarone reduced 4-aminopyridine-evoked Ca2+-dependent glutamate release and cytosolic Ca2+ concentration elevation. Amiodarone did not affect the 4-aminopyridine-evoked depolarization of the synaptosomal membrane potential or the Na+ channel activator veratridine-evoked glutamate release, indicating that the amiodarone-mediated inhibition of glutamate release is not caused by a decrease in synaptosomal excitability. The inhibitory effect of amiodarone on 4-aminopyridine-evoked glutamate release was markedly decreased in synaptosomes pretreated with the Cav2.2 (N-type and Cav2.1 (P/Q-type channel blocker ω-conotoxin MVIIC, the calmodulin antagonists W7 and calmidazolium, or the protein kinase A inhibitors H89 and KT5720. However, the intracellular Ca2+-release inhibitors dantrolene and CGP37157 had no effect on the amiodarone-mediated inhibition of glutamate release. Furthermore, amiodarone reduced the frequency of miniature excitatory postsynaptic currents without affecting their amplitude in hippocampal slices. Our data suggest that amiodarone reduces Ca2+ influx through N- and P/Q-type Ca2+ channels, subsequently reducing the Ca2+-calmodulin/protein kinase A cascade to inhibit the evoked glutamate release from rat hippocampal nerve terminals.

  7. All polymer chip for amperometric studies of transmitter release from large groups of neuronal cells

    DEFF Research Database (Denmark)

    Larsen, Simon T.; Taboryski, Rafael

    2012-01-01

    -induced release of transmitter molecules. The nature of the resulting current peaks is discussed, and the time for restoring transmitter reservoirs is studied. The relationship between released transmitters and potassium concentration was found to fit to a sigmoidal dose–response curve. Finally, we demonstrate...

  8. Amiodarone reduces depolarization-evoked glutamate release from hippocampual synaptosomes.

    Science.gov (United States)

    Chang, Chia Yu; Hung, Chi Feng; Huang, Shu Kuei; Kuo, Jinn Rung; Wang, Su Jane

    2017-03-01

    Decreased brain glutamate level has emerged as a new therapeutic approach for epilepsy. This study investigated the effect and mechanism of amiodarone, an anti-arrhythmic drug with antiepileptic activity, on glutamate release in the rat hippocampus. In a synaptosomal preparation, amiodarone reduced 4-aminopyridine-evoked Ca2+-dependent glutamate release and cytosolic Ca2+ concentration elevation. Amiodarone did not affect the 4-aminopyridine-evoked depolarization of the synaptosomal membrane potential or the Na+ channel activator veratridine-evoked glutamate release, indicating that the amiodarone-mediated inhibition of glutamate release is not caused by a decrease in synaptosomal excitability. The inhibitory effect of amiodarone on 4-aminopyridine-evoked glutamate release was markedly decreased in synaptosomes pretreated with the Cav2.2 (N-type) and Cav2.1 (P/Q-type) channel blocker ω-conotoxin MVIIC, the calmodulin antagonists W7 and calmidazolium, or the protein kinase A inhibitors H89 and KT5720. However, the intracellular Ca2+-release inhibitors dantrolene and CGP37157 had no effect on the amiodarone-mediated inhibition of glutamate release. Furthermore, amiodarone reduced the frequency of miniature excitatory postsynaptic currents without affecting their amplitude in hippocampal slices. Our data suggest that amiodarone reduces Ca2+ influx through N- and P/Q-type Ca2+ channels, subsequently reducing the Ca2+-calmodulin/protein kinase A cascade to inhibit the evoked glutamate release from rat hippocampal nerve terminals. Copyright © 2017 The Authors. Production and hosting by Elsevier B.V. All rights reserved.

  9. Transmitter modulation of spike-evoked calcium transients in arousal related neurons

    DEFF Research Database (Denmark)

    Kohlmeier, Kristi Anne; Leonard, Christopher S

    2006-01-01

    -evoked intracellular calcium transients dampen excitability and stimulate NO production in these neurons. In this study, we investigated the action of several arousal-related neurotransmitters and the role of specific calcium channels in these LDT Ca(2+)-transients by simultaneous whole-cell recording and calcium...

  10. Contribution of presynaptic calcium-activated potassium currents to transmitter release regulation in cultured Xenopus nerve-muscle synapses.

    Science.gov (United States)

    Pattillo, J M; Yazejian, B; DiGregorio, D A; Vergara, J L; Grinnell, A D; Meriney, S D

    2001-01-01

    Using Xenopus nerve-muscle co-cultures, we have examined the contribution of calcium-activated potassium (K(Ca)) channels to the regulation of transmitter release evoked by single action potentials. The presynaptic varicosities that form on muscle cells in these cultures were studied directly using patch-clamp recording techniques. In these developing synapses, blockade of K(Ca) channels with iberiotoxin or charybdotoxin decreased transmitter release by an average of 35%. This effect would be expected to be caused by changes in the late phases of action potential repolarization. We hypothesize that these changes are due to a reduction in the driving force for calcium that is normally enhanced by the local hyperpolarization at the active zone caused by potassium current through the K(Ca) channels that co-localize with calcium channels. In support of this hypothesis, we have shown that when action potential waveforms were used as voltage-clamp commands to elicit calcium current in varicosities, peak calcium current was reduced only when these waveforms were broadened beginning when action potential repolarization was 20% complete. In contrast to peak calcium current, total calcium influx was consistently increased following action potential broadening. A model, based on previously reported properties of ion channels, faithfully reproduced predicted effects on action potential repolarization and calcium currents. From these data, we suggest that the large-conductance K(Ca) channels expressed at presynaptic varicosities regulate transmitter release magnitude during single action potentials by altering the rate of action potential repolarization, and thus the magnitude of peak calcium current.

  11. NLP-12 engages different UNC-13 proteins to potentiate tonic and evoked release.

    Science.gov (United States)

    Hu, Zhitao; Vashlishan-Murray, Amy B; Kaplan, Joshua M

    2015-01-21

    A neuropeptide (NLP-12) and its receptor (CKR-2) potentiate tonic and evoked ACh release at Caenorhabditis elegans neuromuscular junctions. Increased evoked release is mediated by a presynaptic pathway (egl-30 Gαq and egl-8 PLCβ) that produces DAG, and by DAG binding to short and long UNC-13 proteins. Potentiation of tonic ACh release persists in mutants deficient for egl-30 Gαq and egl-8 PLCβ and requires DAG binding to UNC-13L (but not UNC-13S). Thus, NLP-12 adjusts tonic and evoked release by distinct mechanisms. Copyright © 2015 the authors 0270-6474/15/351038-05$15.00/0.

  12. Conductive Polymer Microelectrodes for on-chip measurement of transmitter release from living cells

    DEFF Research Database (Denmark)

    Larsen, Simon Tylsgaard; Matteucci, Marco; Taboryski, Rafael J.

    2012-01-01

    In this paper, we present techniques to trap a group of neuronal cells (PC 12) close to band microelectrodes and quantitatively measure cellular transmitter release. Different trapping approaches were investigated including coating of electrodes by layers enhancing cell attachment and by pressure...

  13. New Treatments for Drug-Resistant Epilepsy that Target Presynaptic Transmitter Release

    Science.gov (United States)

    2013-05-01

    Live cell imaging of mossy fiber boutons in acute hippocampal slices was done by bulk loading a group of granule cells and their axons with Alexa...whether post- SE leads to functional differences in transmitter release from excitatory mossy fiber boutons we utilized two-photon live cell imaging in

  14. How Do RIM-BPs Link Voltage-Gated Ca(2+) Channels to Evoked Neurotransmitter Release?

    Science.gov (United States)

    Li, Ying C; Kavalali, Ege T

    2015-09-23

    Coupling between voltage-gated Ca(2+) influx and synaptic vesicle exocytosis is essential for rapid evoked neurotransmission. Acuna et al. show that the knockout of RIM-BPs, which are key structural components of this coupling, decreases the reliability of evoked neurotransmitter release. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. Temperature differentially facilitates spontaneous but not evoked glutamate release from cranial visceral primary afferents.

    Directory of Open Access Journals (Sweden)

    Jessica A Fawley

    Full Text Available Temperature is fundamentally important to all biological functions including synaptic glutamate release. Vagal afferents from the solitary tract (ST synapse on second order neurons in the nucleus of the solitary tract, and glutamate release at this first central synapse controls autonomic reflex function. Expression of the temperature-sensitive Transient Receptor Potential Vanilloid Type 1 receptor separates ST afferents into C-fibers (TRPV1+ and A-fibers (TRPV1-. Action potential-evoked glutamate release is similar between C- and A-fiber afferents, but TRPV1 expression facilitates a second form of synaptic glutamate release in C-fibers by promoting substantially more spontaneous glutamate release. The influence of temperature on different forms of glutamate release is not well understood. Here we tested how temperature impacts the generation of evoked and spontaneous release of glutamate and its relation to TRPV1 expression. In horizontal brainstem slices of rats, activation of ST primary afferents generated synchronous evoked glutamate release (ST-eEPSCs at constant latency whose amplitude reflects the probability of evoked glutamate release. The frequency of spontaneous EPSCs in these same neurons measured the probability of spontaneous glutamate release. We measured both forms of glutamate from each neuron during ramp changes in bath temperature of 4-5 °C. Spontaneous glutamate release from TRPV1+ closely tracked with these thermal changes indicating changes in the probability of spontaneous glutamate release. In the same neurons, temperature changed axon conduction registered as latency shifts but ST-eEPSC amplitudes were constant and independent of TRPV1 expression. These data indicate that TRPV1-operated glutamate release is independent of action potential-evoked glutamate release in the same neurons. Together, these support the hypothesis that evoked and spontaneous glutamate release originate from two pools of vesicles that are

  16. Axonal GABAA receptors depolarize presynaptic terminals and facilitate transmitter release in cerebellar Purkinje cells.

    Science.gov (United States)

    Zorrilla de San Martin, Javier; Trigo, Federico F; Kawaguchi, Shin-Ya

    2017-10-26

    In neurons of the adult brain, somatodendritic GABAA Rs mediate fast synaptic inhibition and play a crucial role in synaptic integration. GABAA Rs are not only present in the somatodendritic compartment, but also in the axonal compartment where they modulate action potential (AP) propagation and transmitter release. Although presynaptic GABAA Rs have been reported in various brain regions, their mechanisms of action and physiological roles remain obscure, particularly at GABAergic boutons. Here, using a combination of direct whole-bouton or perforated patch-clamp recordings and local GABA photolysis in single axonal varicosities of cerebellar Purkinje cells, we investigate the subcellular localization and functional role of axonal GABAA Rs both in primary cultures and acute slices. Our results indicate that presynaptic terminals of PCs carry GABAA Rs that behave as auto-receptors; their activation leads to a depolarization of the terminal membrane after an AP due to the relatively high cytoplasmic Cl(-) concentration in the axon, but do not modulate the AP itself. Paired recordings from different terminals of the same axon show that the GABAA R-mediated local depolarizations propagate substantially to neighboring varicosities. Finally, the depolarization mediated by presynaptic GABAA R activation augmented Ca(2+) influx and transmitter release, resulting in a marked effect on short-term plasticity. Altogether, our results reveal a mechanism by which presynaptic GABAA Rs influence neuronal computation. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  17. Mechanisms of constitutive and ATP-evoked ATP release in neonatal mouse olfactory epithelium

    Directory of Open Access Journals (Sweden)

    Hayoz Sébastien

    2012-05-01

    Full Text Available Abstract Background ATP is an extracellular signaling molecule with many ascribed functions in sensory systems, including the olfactory epithelium. The mechanism(s by which ATP is released in the olfactory epithelium has not been investigated. Quantitative luciferin-luciferase assays were used to monitor ATP release, and confocal imaging of the fluorescent ATP marker quinacrine was used to monitor ATP release via exocytosis in Swiss Webster mouse neonatal olfactory epithelial slices. Results Under control conditions, constitutive release of ATP occurs via exocytosis, hemichannels and ABC transporters and is inhibited by vesicular fusion inhibitor Clostridium difficile toxin A and hemichannel and ABC transporter inhibitor probenecid. Constitutive ATP release is negatively regulated by the ATP breakdown product ADP through activation of P2Y receptors, likely via the cAMP/PKA pathway. In vivo studies indicate that constitutive ATP may play a role in neuronal homeostasis as inhibition of exocytosis inhibited normal proliferation in the OE. ATP-evoked ATP release is also present in mouse neonatal OE, triggered by several ionotropic P2X purinergic receptor agonists (ATP, αβMeATP and Bz-ATP and a G protein-coupled P2Y receptor agonist (UTP. Calcium imaging of P2X2-transfected HEK293 “biosensor” cells confirmed the presence of evoked ATP release. Following purinergic receptor stimulation, ATP is released via calcium-dependent exocytosis, activated P2X1,7 receptors, activated P2X7 receptors that form a complex with pannexin channels, or ABC transporters. The ATP-evoked ATP release is inhibited by the purinergic receptor inhibitor PPADS, Clostridium difficile toxin A and two inhibitors of pannexin channels: probenecid and carbenoxolone. Conclusions The constitutive release of ATP might be involved in normal cell turn-over or modulation of odorant sensitivity in physiological conditions. Given the growth-promoting effects of ATP, ATP-evoked ATP

  18. Enhancement by Anemonia sulcata toxin II of spontaneous quantal transmitter release from mammalian motor nerve terminals.

    Science.gov (United States)

    Molgo, J; Lemeignan, M; Tazieff-Depierre, F

    1986-01-01

    The action of Anemonia sulcata toxin II (ATX-II) on spontaneous quantal transmitter release from motor nerve terminals was investigated by recording miniature end-plate potentials (MEPPs) from isolated mouse phrenic nerve--hemidiaphragm nerve--muscle preparations. ATX-II (3.2 microM) when applied for 3-40 min to junctions bathed in a normal ionic medium enhanced about one hundred fold the rate of spontaneous MEPPs. Concomitantly, ATX-II depolarized the muscle fiber. The effect of the toxin on MEPP frequency was markedly reduced when junctions were exposed to Na-deficient solutions or pre-treated with dantrolene sodium (10 microM). ATX-II (0.24-3.2 microM) increased MEPP rate in junctions exposed to a Ca-free medium containing 2 mM EGTA and 2 mM Mg2+ in a dose- and time-dependent manner. Tetrodotoxin (0.2-1 microM) prevented the effects of ATX-II on MEPP frequency and on the resting membrane potential of muscle fibers. Tetrodotoxin also antagonized the acceleration of MEPP induced by ATX-II. The experimental findings suggest that ATX-II acts to increase quantal transmitter output from motor nerve terminals by enhancing Na+ influx through tetrodotoxin-sensitive presynaptic channels, since ATX-II action does not appear to depend upon entry of Ca2+ from the extracellular medium. It is likely that ATX-II, by increasing intraterminal Na+ concentration, may trigger calcium release from internal stores.

  19. Sex differences in formalin-evoked primary afferent release of substance P.

    Science.gov (United States)

    Nazarian, A; Tenayuca, J M; Almasarweh, F; Armendariz, A; Are, D

    2014-01-01

    Sex differences in pain have been well documented; however, the mechanisms involved remain to be elucidated. The present study examined whether sex differences exist in the functioning of primary afferent fibres by assessing formalin-evoked release of substance P by way of neurokinin 1 receptor (NK1r) internalization. The study also investigated whether the observed effects would be oestradiol-sensitive. Intact and gonadectomized male and female rats were given intraplantar formalin and then euthanized either 5 or 30 min later, representing phase 1 or 2 of the formalin response, respectively. In a subsequent experiment, ovariectomized females received oestradiol prior to formalin administration. Lastly, formalin-evoked NK1r internalization was assessed across the female oestrous cycle. Intraplantar formalin evoked significant NK1r internalization, during phase 1 and 2, in both males and females. During phase 1, no differences in NK1r internalization were detected between males or females, regardless of the gonadal status. In contrast, during phase 2, intact females exhibited greater NK1r internalization than intact males. Moreover, ovariectomy reduced NK1r internalization as compared to intact females, whereas castration had no effect as compared to intact males. Oestradiol supplementation in ovariectomized females increased NK1r internalization to levels observed in intact females. Formalin-evoked NK1r internalization did not differ across the oestrous cycle. These findings suggest that oestradiol mediates sex differences in formalin-evoked substance P release, which may contribute to a differential development of central sensitization and pain behaviours in males and females. © 2013 European Pain Federation - EFIC®

  20. Hyperosmolarity evokes histamine release from ileum mucosa by stimulating a cholinergic pathway.

    Science.gov (United States)

    Wang, Banqin; An, Ning; Shaikh, Abdul Sami; Wang, Haoyi; Xiao, Ling; Liu, Hongwei; Li, Jingxin; Zhao, Dongbo

    2017-11-18

    Changes in extracellular osmolarity lead to alteration in cellular volume. In the study, we examined the effects of hyperosmolarity on short-circuit currents (Isc) in the rat ileum using the Ussing chamber technique. Mucosal exposure to 20 mM glucose evoked a decrease of ISC in the rat ileum, which was antagonized by the stretch-activated channel blocker GdCl3, TTX and atropine, respectively. In contrast, it was not blocked by phlorizin, a Na+-glucose cotransporter SGLT1 inhibitor. Furthermore, the unabsorbed substances, such as sucrose, lactulose or urea, also induced a decrease of ISC in rat ileum. ELISA results revealed that 20 mM glucose stimulated the release of histamine from rat ileum mucosa, which was attenuated by TTX. In addition, the glucose-induced ISC was depressed by pyrilamine, a histamine H1 receptor blocker (H1 antagonist) whereas it was not affected by ranitidine (H2 antagonist), clobenpropit (H3 antagonists) or JNJ7777120 (H4 antagonist), respectively. The ion substitution experiments suggest that the changes of Na+ and HCO3- ion flux underlie the glucose-induced ISC. In conclusion, osmotic stimulus decreased the basal ISC of rat ileum by evoking histamine release from ileum mucosa. The changes of Na+ and HCO3- ion transport are involved in the glucose-evoked decrease of basal ISC. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Acetylcholine-induced inhibition of presynaptic calcium signals and transmitter release in the frog neuromuscular junction

    Directory of Open Access Journals (Sweden)

    Eduard Khaziev

    2016-12-01

    Full Text Available Acetylcholine (ACh, released from axonal terminals of motor neurones in neuromuscular junctions regulates the efficacy of neurotransmission through activation of presynaptic nicotinic and muscarinic autoreceptors. Receptor-mediated presynaptic regulation could reflect either direct action on exocytotic machinery or modulation of Ca2+ entry and resulting intra-terminal Ca2+ dynamics. We have measured free intra-terminal cytosolic Ca2+ ([Ca2+]i using Oregon-Green 488 microfluorimetry, in parallel with voltage-clamp recordings of spontaneous (mEPC and evoked (EPC postsynaptic currents in post-junctional skeletal muscle fibre. Activation of presynaptic muscarinic and nicotinic receptors with exogenous acetylcholine and its non-hydrolized analogue carbachol reduced amplitude of the intra-terminal [Ca2+]i transients and decreased quantal content (calculated by dividing the area under EPC curve by the area under mEPC curve. Pharmacological analysis revealed the role of muscarinic receptors of M2 subtype as well as d-tubocurarine-sensitive nicotinic receptor in presynaptic modulation of [Ca2+]i transients. Modulation of synaptic transmission efficacy by ACh receptors was completely eliminated by pharmacological inhibition of N-type Ca2+ channels. We conclude that ACh receptor-mediated reduction of Ca2+ entry into the nerve terminal through N-type Ca2+ channels represents one of possible mechanism of presynaptic modulation in frog neuromuscular junction.

  2. Objective measures of binaural masking level differences and comodulation masking release based on late auditory evoked potentials

    DEFF Research Database (Denmark)

    Epp, Bastian; Yasin, Ifat; Verhey, Jesko L.

    2013-01-01

    The audibility of important sounds is often hampered due to the presence of other masking sounds. The present study investigates if a correlate of the audibility of a tone masked by noise is found in late auditory evoked potentials measured from human listeners. The audibility of the target sound...... in a masking release (i: binaural masking level difference; ii: comodulation masking release) compared to a condition where those cues are not present. Late auditory evoked potentials (N1, P2) were recorded for the stimuli at a constant masker level, but different signal levels within the same set of listeners...

  3. Monoamine Release in the Cat Lumbar Spinal Cord during Fictive Locomotion Evoked by the Mesencephalic Locomotor Region

    Directory of Open Access Journals (Sweden)

    Brian R. Noga

    2017-08-01

    Full Text Available Spinal cord neurons active during locomotion are innervated by descending axons that release the monoamines serotonin (5-HT and norepinephrine (NE and these neurons express monoaminergic receptor subtypes implicated in the control of locomotion. The timing, level and spinal locations of release of these two substances during centrally-generated locomotor activity should therefore be critical to this control. These variables were measured in real time by fast-cyclic voltammetry in the decerebrate cat’s lumbar spinal cord during fictive locomotion, which was evoked by electrical stimulation of the mesencephalic locomotor region (MLR and registered as integrated activity in bilateral peripheral nerves to hindlimb muscles. Monoamine release was observed in dorsal horn (DH, intermediate zone/ventral horn (IZ/VH and adjacent white matter (WM during evoked locomotion. Extracellular peak levels (all sites increased above baseline by 138 ± 232.5 nM and 35.6 ± 94.4 nM (mean ± SD for NE and 5-HT, respectively. For both substances, release usually began prior to the onset of locomotion typically earliest in the IZ/VH and peaks were positively correlated with net activity in peripheral nerves. Monoamine levels gradually returned to baseline levels or below at the end of stimulation in most trials. Monoamine oxidase and uptake inhibitors increased the release magnitude, time-to-peak (TTP and decline-to-baseline. These results demonstrate that spinal monoamine release is modulated on a timescale of seconds, in tandem with centrally-generated locomotion and indicate that MLR-evoked locomotor activity involves concurrent activation of descending monoaminergic and reticulospinal pathways. These gradual changes in space and time of monoamine concentrations high enough to strongly activate various receptors subtypes on locomotor activated neurons further suggest that during MLR-evoked locomotion, monoamine action is, in part, mediated by extrasynaptic

  4. Diazepam Inhibits Electrically Evoked and Tonic Dopamine Release in the Nucleus Accumbens and Reverses the Effect of Amphetamine.

    Science.gov (United States)

    Gomez-A, Alexander; Fiorenza, Amanda M; Boschen, Suelen L; Sugi, Adam H; Beckman, Danielle; Ferreira, Sergio T; Lee, Kendall; Blaha, Charles D; Da Cunha, Claudio

    2017-02-15

    Diazepam is a benzodiazepine receptor agonist with anxiolytic and addictive properties. Although most drugs of abuse increase the level of release of dopamine in the nucleus accumbens, here we show that diazepam not only causes the opposite effect but also prevents amphetamine from enhancing dopamine release. We used 20 min sampling in vivo microdialysis and subsecond fast-scan cyclic voltammetry recordings at carbon-fiber microelectrodes to show that diazepam caused a dose-dependent decrease in the level of tonic and electrically evoked dopamine release in the nucleus accumbens of urethane-anesthetized adult male Swiss mice. In fast-scan cyclic voltammetry assays, dopamine release was evoked by electrical stimulation of the ventral tegmental area. We observed that 2 and 3 mg of diazepam/kg reduced the level of electrically evoked dopamine release, and this effect was reversed by administration of the benzodiazepine receptor antagonist flumazenil in doses of 2.5 and 5 mg/kg, respectively. No significant effects on measures of dopamine re-uptake were observed. Cyclic voltammetry experiments further showed that amphetamine (5 mg/kg, intraperitoneally) caused a significant increase in the level of dopamine release and in the half-life for dopamine re-uptake. Diazepam (2 mg/kg) significantly weakened the effect of amphetamine on dopamine release without affecting dopamine re-uptake. These results suggest that the pharmacological effects of benzodiazepines have a dopaminergic component. In addition, our findings challenge the classic view that all drugs of abuse cause dopamine release in the nucleus accumbens and suggest that benzodiazepines could be useful in the treatment of addiction to other drugs that increase the level of dopamine release, such as cocaine, amphetamines, and nicotine.

  5. Upregulation of transmitter release probability improves a conversion of synaptic analogue signals into neuronal digital spikes

    Science.gov (United States)

    2012-01-01

    Action potentials at the neurons and graded signals at the synapses are primary codes in the brain. In terms of their functional interaction, the studies were focused on the influence of presynaptic spike patterns on synaptic activities. How the synapse dynamics quantitatively regulates the encoding of postsynaptic digital spikes remains unclear. We investigated this question at unitary glutamatergic synapses on cortical GABAergic neurons, especially the quantitative influences of release probability on synapse dynamics and neuronal encoding. Glutamate release probability and synaptic strength are proportionally upregulated by presynaptic sequential spikes. The upregulation of release probability and the efficiency of probability-driven synaptic facilitation are strengthened by elevating presynaptic spike frequency and Ca2+. The upregulation of release probability improves spike capacity and timing precision at postsynaptic neuron. These results suggest that the upregulation of presynaptic glutamate release facilitates a conversion of synaptic analogue signals into digital spikes in postsynaptic neurons, i.e., a functional compatibility between presynaptic and postsynaptic partners. PMID:22852823

  6. Transmitter release from cochlear hair cells is phase-locked to cyclic stimuli of different intensities and frequencies

    Science.gov (United States)

    2013-01-01

    The auditory system processes time and intensity through separate brainstem pathways to derive spatial location as well as other salient features of sound. The independent coding of time and intensity begins in the cochlea where afferent neurons can fire action potentials at constant phase throughout a wide range of stimulus intensities. We have investigated time and intensity coding by simultaneous pre- and post-synaptic recording at the hair cell-afferent synapse from rats. Trains of depolarizing steps to the hair cell were used to elicit postsynaptic currents that occurred at constant phase, for a range of membrane potentials over which release probability varied significantly. To probe the underlying mechanisms, release was examined using single steps to various command voltages. As expected for vesicular release, first synaptic events occurred earlier as presynaptic calcium influx grew larger. However, synaptic depression produced smaller responses with longer first latencies. Thus, during repetitive hair cell stimulation, as the hair cell is more strongly depolarized, increased calcium channel gating hurries transmitter release, but the resulting vesicular depletion produces a compensatory slowing. Quantitative simulation of ribbon function shows that these two factors varied reciprocally with hair cell depolarization (stimulus intensity) to produce constant synaptic phase. Finally, we propose that the observed rapid vesicle replenishment would help maintain the vesicle pool, which in turn would equilibrate with the stimulus intensity (and therefore, the number of open Ca2+ channels), so for trains of different levels the average phase will be conserved. PMID:23175853

  7. Action Potential-Evoked Calcium Release Is Impaired in Single Skeletal Muscle Fibers from Heart Failure Patients

    Science.gov (United States)

    DiFranco, Marino; Quiñonez, Marbella; Shieh, Perry; Fonarow, Gregg C.; Cruz, Daniel; Deng, Mario C.; Vergara, Julio L.; Middlekauff, Holly R.

    2014-01-01

    Background Exercise intolerance in chronic heart failure (HF) has been attributed to abnormalities of the skeletal muscles. Muscle function depends on intact excitation-contraction coupling (ECC), but ECC studies in HF models have been inconclusive, due to deficiencies in the animal models and tools used to measure calcium (Ca2+) release, mandating investigations in skeletal muscle from HF patients. The purpose of this study was to test the hypothesis that Ca2+ release is significantly impaired in the skeletal muscle of HF patients in whom exercise capacity is severely diminished compared to age-matched healthy volunteers. Methods and Findings Using state-of-the-art electrophysiological and optical techniques in single muscle fibers from biopsies of the locomotive vastus lateralis muscle, we measured the action potential (AP)-evoked Ca2+ release in 4 HF patients and 4 age-matched healthy controls. The mean peak Ca2+ release flux in fibers obtained from HF patients (10±1.2 µM/ms) was markedly (2.6-fold) and significantly (pfibers from healthy volunteers (28±3.3 µM/ms). This impairment in AP-evoked Ca2+ release was ubiquitous and was not explained by differences in the excitability mechanisms since single APs were indistinguishable between HF patients and healthy volunteers. Conclusions These findings prove the feasibility of performing electrophysiological experiments in single fibers from human skeletal muscle, and offer a new approach for investigations of myopathies due to HF and other diseases. Importantly, we have demonstrated that one step in the ECC process, AP-evoked Ca2+ release, is impaired in single muscle fibers in HF patients. PMID:25310188

  8. Action potential-evoked calcium release is impaired in single skeletal muscle fibers from heart failure patients.

    Directory of Open Access Journals (Sweden)

    Marino DiFranco

    Full Text Available Exercise intolerance in chronic heart failure (HF has been attributed to abnormalities of the skeletal muscles. Muscle function depends on intact excitation-contraction coupling (ECC, but ECC studies in HF models have been inconclusive, due to deficiencies in the animal models and tools used to measure calcium (Ca2+ release, mandating investigations in skeletal muscle from HF patients. The purpose of this study was to test the hypothesis that Ca2+ release is significantly impaired in the skeletal muscle of HF patients in whom exercise capacity is severely diminished compared to age-matched healthy volunteers.Using state-of-the-art electrophysiological and optical techniques in single muscle fibers from biopsies of the locomotive vastus lateralis muscle, we measured the action potential (AP-evoked Ca2+ release in 4 HF patients and 4 age-matched healthy controls. The mean peak Ca2+ release flux in fibers obtained from HF patients (10±1.2 µM/ms was markedly (2.6-fold and significantly (p<0.05 smaller than in fibers from healthy volunteers (28±3.3 µM/ms. This impairment in AP-evoked Ca2+ release was ubiquitous and was not explained by differences in the excitability mechanisms since single APs were indistinguishable between HF patients and healthy volunteers.These findings prove the feasibility of performing electrophysiological experiments in single fibers from human skeletal muscle, and offer a new approach for investigations of myopathies due to HF and other diseases. Importantly, we have demonstrated that one step in the ECC process, AP-evoked Ca2+ release, is impaired in single muscle fibers in HF patients.

  9. DMSO Chemically Alters Cell Membranes to Slow Exocytosis and Increase the Fraction of Partial Transmitter Released.

    Science.gov (United States)

    Majdi, Soodabeh; Najafinobar, Neda; Dunevall, Johan; Lovric, Jelena; Ewing, Andrew G

    2017-10-05

    Dimethyl sulfoxide (DMSO) is frequently used as a solvent in biological studies and as a vehicle for drug therapy; but the side effects of DMSO, especially on the cell environment, are not well understood, and controls with DMSO are not neutral at higher concentrations. Herein, electrochemical measurement techniques are applied to show that DMSO increases exocytotic neurotransmitter release, while leaving vesicular contents unchanged. In addition, the kinetics of release from DMSO-treated cells are faster than that of untreated ones. The results suggest that DMSO has a significant influence on the chemistry of the cell membrane, leading to alteration of exocytosis. A speculative chemical mechanism of the effect on the fusion pore during exocytosis is presented. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Extrasynaptic vesicular transmitter release from the somata of substantia nigra neurons in rat midbrain slices.

    Science.gov (United States)

    Jaffe, E H; Marty, A; Schulte, A; Chow, R H

    1998-05-15

    Substantia nigra neurons release dopamine from their somatodendritic regions. A long-unresolved question is whether this release occurs by exocytosis or by a nonvesicular mechanism. We used carbon fiber microelectrodes in a brainstem slice to assay secretion from single cell bodies that had been cleared of connective tissue. Amperometry at the carbon fiber microelectrodes revealed unitary events in approximately 90% of cells in resting conditions. These events had charge integrals ranging from a few femtocoulombs to several hundred femtocoulombs (fC). Local glutamate application enhanced the event frequency by 3.5-fold on average and up to 10-fold in highly responsive cells, although the mean charge integral was not modified. Local application of a high K+-containing saline had effects similar to those of glutamate. The frequency of resting and stimulated amperometric events was much lower at 21-22 degreesC than at 32-35 degreesC. The addition of Cd2+ (50 microM), a blocker of voltage-dependent Ca2+ channels, to the bath solution blocked the stimulatory effects of glutamate. These results suggest that dopamine is released from the somata of substantia nigra neurons by exocytosis and that this mechanism is regulated by neuronal electrical activity. More generally, this study demonstrates the applicability of carbon fiber microelectrodes to the measurement of quantal monoamine secretion in brain slices.

  11. Acute stress increases depolarization-evoked glutamate release in the rat prefrontal/frontal cortex: the dampening action of antidepressants.

    Directory of Open Access Journals (Sweden)

    Laura Musazzi

    2010-01-01

    Full Text Available Behavioral stress is recognized as a main risk factor for neuropsychiatric diseases. Converging evidence suggested that acute stress is associated with increase of excitatory transmission in certain forebrain areas. Aim of this work was to investigate the mechanism whereby acute stress increases glutamate release, and if therapeutic drugs prevent the effect of stress on glutamate release.Rats were chronically treated with vehicle or drugs employed for therapy of mood/anxiety disorders (fluoxetine, desipramine, venlafaxine, agomelatine and then subjected to unpredictable footshock stress. Acute stress induced marked increase in depolarization-evoked release of glutamate from synaptosomes of prefrontal/frontal cortex in superfusion, and the chronic drug treatments prevented the increase of glutamate release. Stress induced rapid increase in the circulating levels of corticosterone in all rats (both vehicle- and drug-treated, and glutamate release increase was blocked by previous administration of selective antagonist of glucocorticoid receptor (RU 486. On the molecular level, stress induced accumulation of presynaptic SNARE complexes in synaptic membranes (both in vehicle- and drug-treated rats. Patch-clamp recordings of pyramidal neurons in the prefrontal cortex revealed that stress increased glutamatergic transmission through both pre- and postsynaptic mechanisms, and that antidepressants may normalize it by reducing release probability.Acute footshock stress up-regulated depolarization-evoked release of glutamate from synaptosomes of prefrontal/frontal cortex. Stress-induced increase of glutamate release was dependent on stimulation of glucocorticoid receptor by corticosterone. Because all drugs employed did not block either elevation of corticosterone or accumulation of SNARE complexes, the dampening action of the drugs on glutamate release must be downstream of these processes. This novel effect of antidepressants on the response to stress

  12. Gastrin-releasing peptide is a transmitter mediating porcine gallbladder contraction

    DEFF Research Database (Denmark)

    Schjoldager, Birgit; Poulsen, S.S.; Schmidt, P.

    1991-01-01

    We studied the role of gastrin-releasing peptide (GRP) for porcine gallbladder motility. Immunohistochemistry visualized nerve fibers containing GRP-like immunoreactivity in muscularis. GRP concentration dependently stimulated contractions of muscularis strips (ED50, 2.9 nM). Neuromedin B was less...... potent (ED50, 0.1 microM), suggesting existence of GRP-preferring receptors. GRP-induced contractions were unaffected by muscarinic antagonism (1 microM atropine), axonal blockade (1 microM tetrodotoxin), cholecystokinin (CCK) receptor antagonism (10 microM MK-329), or substance P desensitization (1......-(6-13)PA interacted specifically with GRP receptors; while abolishing responses to GRP (1 nM), responses to substance P (0.1 microM) and CCK-8 (1 nM) were unchanged. Electrical stimulation (10 Hz, 0.5 ms, 10 V) caused a rapid onset-slow offset, tetrodotoxin-sensitive excitation. Atropine reduced...

  13. Presynaptic transporter-mediated release of glutamate evoked by the protonophore FCCP increases under altered gravity conditions

    Science.gov (United States)

    Borisova, T. A.; Krisanova, N. V.

    2008-12-01

    High-affinity Na +-dependent glutamate transporters of the plasma membrane mediate the glutamate uptake into neurons, and thus maintain low levels of extracellular glutamate in the synaptic cleft. The study focused on the release of glutamate by reversal of Na +-dependent glutamate transporters from rat brain nerve terminals (synaptosomes) under conditions of centrifuge-induced hypergravity. Flow cytometric analysis revealed similarity in the size and cytoplasmic granularity between synaptosomal preparations obtained from control and G-loaded animals (10 G, 1 h). The release of cytosolic L-[ 14C]glutamate from synaptosomes was evaluated using the protonophore FCCP, which dissipated synaptic vesicle proton gradient, thus synaptic vesicles were not able to keep glutamate inside and the latter enriched cytosol. FCCP per se induced the greater release of L-[ 14C]glutamate in hypergravity as compared to control (4.8 ± 1.0% and 8.0 ± 1.0% of total label). Exocytotic release of L-[ 14C]glutamate evoked by depolarization was reduced down to zero after FCCP application under both conditions studied. Depolarization stimulated release of cytosolic L-[ 14C]glutamate from synaptosomes preliminary treated with FCCP was considerably increased from 27.0 ± 2.2% of total label in control to 35.0 ± 2.3% in hypergravity. Non-transportable inhibitor of glutamate transporter DL-threo-β-benzyloxyaspartate was found to significantly inhibit high-KCl and FCCP-stimulated release of L-[ 14C]glutamate, confirming the release by reversal of glutamate transporters. The enhancement of transporter-mediated release of glutamate in hypergravity was found to result at least partially from the inhibition of the activity of Na/K-ATPase in the plasma membrane of synaptosomes. We suggested that hypergravity-induced alteration in transporter-mediated release of glutamate indicated hypoxic injury of neurons.

  14. Glutamate may be an efferent transmitter that elicits inhibition in mouse taste buds.

    Directory of Open Access Journals (Sweden)

    Yijen A Huang

    Full Text Available Recent studies suggest that l-glutamate may be an efferent transmitter released from axons innervating taste buds. In this report, we determined the types of ionotropic synaptic glutamate receptors present on taste cells and that underlie this postulated efferent transmission. We also studied what effect glutamate exerts on taste bud function. We isolated mouse taste buds and taste cells, conducted functional imaging using Fura 2, and used cellular biosensors to monitor taste-evoked transmitter release. The findings show that a large fraction of Presynaptic (Type III taste bud cells (∼50% respond to 100 µM glutamate, NMDA, or kainic acid (KA with an increase in intracellular Ca(2+. In contrast, Receptor (Type II taste cells rarely (4% responded to 100 µM glutamate. At this concentration and with these compounds, these agonists activate glutamatergic synaptic receptors, not glutamate taste (umami receptors. Moreover, applying glutamate, NMDA, or KA caused taste buds to secrete 5-HT, a Presynaptic taste cell transmitter, but not ATP, a Receptor cell transmitter. Indeed, glutamate-evoked 5-HT release inhibited taste-evoked ATP secretion. The findings are consistent with a role for glutamate in taste buds as an inhibitory efferent transmitter that acts via ionotropic synaptic glutamate receptors.

  15. Electrically evoked GABA release in rat hippocampus CA1 region and its changes during kindling epileptogenesis.

    NARCIS (Netherlands)

    Ghijsen, W.E.J.M.; Zuiderwijk, M.; Lopes da Silva, F.H.

    2007-01-01

    Previous findings on changes in K(+)-induced GABA release from hippocampal slices during kindling epileptogenesis were reinvestigated using physiological electrical stimulation. For that purpose, a procedure was developed enabling neurochemical monitoring of GABA release locally in the CA1 region of

  16. Modification of potassium-evoked release of noradrenaline by various ions and agents

    OpenAIRE

    Kirpekar, S M; Prat, J. C.; Schiavone, M.T.

    1983-01-01

    1 Release of noradrenaline (NA) from isolated spleen slices of the cat by high K+ and tetraethylammonium (TEA) was investigated. Studies were conducted with spleen slices whose tissue stores were prelabelled with [3H]-noradrenaline ([3H]-NA).

  17. Parallel expression of synaptophysin and evoked neurotransmitter release during development of cultured neurons

    DEFF Research Database (Denmark)

    Ehrhart-Bornstein, M; Treiman, M; Hansen, Gert Helge

    1991-01-01

    and neurotransmitter release were measured in each of the culture types as a function of development for up to 8 days in vitro, using the same batch of cells for both sets of measurements to obtain optimal comparisons. The content and the distribution of synaptophysin in the developing cells were assessed...... by quantitative immunoblotting and light microscope immunocytochemistry, respectively. In both cell types, a close parallelism was found between the temporal pattern of development in synaptophysin expression and neurotransmitter release. This temporal pattern differed between the two types of neurons....... The cerebral cortex neurons showed a biphasic time course of increase in synaptophysin content, paralleled by a biphasic pattern of development in their ability to release [3H]GABA in response to depolarization by glutamate or elevated K+ concentrations. In contrast, a monophasic, approximately linear increase...

  18. Systemic pregabalin attenuates facial hypersensitivity and noxious stimulus-evoked release of glutamate in medullary dorsal horn in a rodent model of trigeminal neuropathic pain

    Science.gov (United States)

    Kumar, Naresh; Cherkas, Pavel S.; Varathan, Vidya; Miyamoto, Makiko; Chiang, C.Y.; Dostrovsky, Jonathan O.; Sessle, Barry J.; Coderre, Terence J.

    2013-01-01

    Pregabalin is effective in treating many neuropathic pain conditions. However, the mechanisms of its analgesic effects remain poorly understood. The aim of the present study was to determine whether pregabalin suppresses facial mechanical hypersensitivity and evoked glutamate release in the medullary dorsal horn (MDH) in a rodent model of trigeminal neuropathic pain. Nociceptive mechanical sensitivity was assessed pre-operatively, and then post-operatively 1 h following pregabalin or vehicle (saline) treatment on post-operative days 2 and 5 following infraorbital nerve transection (IONX). In addition, an in vivo microdialysis probe was inserted into the exposed medulla post-operatively and dialysate samples were collected. Glutamate release was then evoked by mustard oil (MO) application to the tooth pulp, and the effects of pregabalin or vehicle were examined on the MDH glutamate release. Glutamate concentrations in the dialysated samples were determined by HPLC, and data analysed by ANOVA. IONX animals (but not control animals) showed facial mechanical hypersensitivity for several days post-operatively. In addition, tooth pulp stimulation with MO evoked a transient release of glutamate in the MDH in IONX animals. Compared to vehicle, administration of pregabalin significantly attenuated the facial mechanical hypersensitivity as well as the MO-evoked glutamate release in MDH. This study provides evidence in support of recent findings pointing to the usefulness of pregabalin in the treatment of orofacial neuropathic pain.1 PMID:23454190

  19. Strong activation of vascular prejunctional beta 2-adrenoceptors in freely moving rats by adrenaline released as a co-transmitter

    NARCIS (Netherlands)

    COPPES, RP; SMIT, J; KHALI, NN; Brouwer, F.; ZAAGSMA, J

    1993-01-01

    The effect of adrenaline on the electrically evoked noradrenaline overflow in the portal vein of adrenal demedullated freely moving rats was studied. Adrenaline (100 ng/min) was infused for 2 h into the portal vein. After a 1-h interval when plasma adrenaline had returned to pre-infusion

  20. pKI values of prazosin and idazoxan for receptors stimulated by neuronally released transmitter in the epididymal portion of rat isolated vas deferens.

    OpenAIRE

    Mackay, D; Kengatharan, M

    1994-01-01

    1. A new method has been used to measure pKI values of prazosin and idazoxan against neuronally-released transmitter in the epididymal portion of the rat isolated vas deferens. The most reproducible results were obtained with a prolonged antagonist equilibration time (1 h). 2. Under these conditions the pKI of prazosin was practically unaffected by addition of alpha, beta-methylene-adenosine-5'-triphosphate (10 microM) to desensitize purinoceptors. Addition of desmethylimipramine (DMI) (0.3 m...

  1. Regional influence of cocaine on evoked dopamine release in the nucleus accumbens core: A role for the caudal brainstem.

    Science.gov (United States)

    Gerth, Ashlynn I; Alhadeff, Amber L; Grill, Harvey J; Roitman, Mitchell F

    2017-01-15

    Cocaine increases dopamine concentration in the nucleus accumbens through competitive binding to the dopamine transporter (DAT). However, it also increases the frequency of dopamine release events, a finding that cannot be explained by action at the DAT alone. Rather, this effect may be mediated by cocaine-induced modulation of brain regions that project to dopamine neurons. To explore regional contributions of cocaine to dopamine signaling, we administered cocaine to the lateral or fourth ventricles and compared the effects on dopamine release in the nucleus accumbens evoked by electrical stimulation of the ventral tegmental area to that of systemically-delivered cocaine. Stimulation trains caused a sharp rise in dopamine followed by a slower return to baseline. The magnitude of dopamine release ([DA]max) as well as the latency to decay to fifty percent of the maximum (t(1/2); index of DAT activity) by each stimulation train were recorded. All routes of cocaine delivery caused an increase in [DA]max; only systemic cocaine caused an increase in t(1/2). Importantly, these data are the first to show that hindbrain (fourth ventricle)-delivered cocaine modulates phasic dopamine signaling. Fourth ventricular cocaine robustly increased cFos immunoreactivity in the nucleus of the solitary tract (NTS), suggesting a neural substrate for hindbrain cocaine-mediated effects on [DA]max. Together, the data demonstrate that cocaine-induced effects on phasic dopamine signaling are mediated via actions throughout the brain including the hindbrain. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  2. Kappa opioid receptor activation potentiates the cocaine-induced increase in evoked dopamine release recorded in vivo in the mouse nucleus accumbens.

    Science.gov (United States)

    Ehrich, Jonathan M; Phillips, Paul E M; Chavkin, Charles

    2014-12-01

    Behavioral stressors increase addiction risk in humans and increase the rewarding valence of drugs of abuse including cocaine, nicotine and ethanol in animal models. Prior studies have established that this potentiation of drug reward was mediated by stress-induced release of the endogenous dynorphin opioids and subsequent kappa opioid receptor (KOR) activation. In this study, we used in vivo fast scan cyclic voltammetry to test the hypothesis that KOR activation before cocaine administration might potentiate the evoked release of dopamine from ventral tegmental (VTA) synaptic inputs to the nucleus accumbens (NAc) and thereby increase the rewarding valence of cocaine. The KOR agonist U50488 inhibited dopamine release evoked by either medial forebrain bundle (MFB) or pedunculopontine tegmental nucleus (PPTg) activation of VTA inputs to the shell or core of the mouse NAc. Cocaine administration increased the dopamine response recorded in either the shell or core evoked by either MFB or PPTg stimulation. Administration of U50488 15 min before cocaine blocked the conditioned place preference (CPP) to cocaine, but only significantly reduced the effect of cocaine on the dopamine response evoked by PPTg stimulation to NAc core. In contrast, administration of U50488 60 min before cocaine significantly potentiated cocaine CPP and significantly increased the effects of cocaine on the dopamine response evoked by either MFB or PPTg stimulation, recorded in either NAc shell or core. Results of this study support the concept that stress-induced activation of KOR by endogenous dynorphin opioids may enhance the rewarding valence of drugs of abuse by potentiating the evoked dopamine response.

  3. pKI values of prazosin and idazoxan for receptors stimulated by neuronally released transmitter in the epididymal portion of rat isolated vas deferens.

    Science.gov (United States)

    Mackay, D; Kengatharan, M

    1994-01-01

    1. A new method has been used to measure pKI values of prazosin and idazoxan against neuronally-released transmitter in the epididymal portion of the rat isolated vas deferens. The most reproducible results were obtained with a prolonged antagonist equilibration time (1 h). 2. Under these conditions the pKI of prazosin was practically unaffected by addition of alpha, beta-methylene-adenosine-5'-triphosphate (10 microM) to desensitize purinoceptors. Addition of desmethylimipramine (DMI) (0.3 microM) produced a small, but statistically non-significant, reduction. 3. The same method has been used to measure the pKI of prazosin against exogenous noradrenaline. In the latter case addition of DMI (0.3 microM) and corticosterone (30 microM) together produced a statistically significant reduction in the apparent pKI of prazosin. 4. The new method for estimating pKI values shows that DMI itself acts either pseudo-irreversibly or non-competitively and may be reducing the apparent pKI of prazosin. 5. The pKI values obtained for prazosin and idazoxan against neuronally-released transmitter are in good agreement with those obtained by other workers for the actions of these drugs on alpha-adrenoceptors.

  4. Lambert-Eaton syndrome IgG inhibits transmitter release via P/Q Ca2+ channels

    OpenAIRE

    Spillane, Jennifer; Ermolyuk, Yaroslav; Cano-Jaimez, Marife; Lang, Bethan; Vincent,Angela; Volynski, Kirill E.; Dimitri M. Kullmann

    2015-01-01

    Objective: To determine whether immunoglobulin G (IgG) from patients with Lambert-Eaton myasthenic syndrome (LEMS) decreases action potential?evoked synaptic vesicle exocytosis, and whether the effect is mediated by P/Q-type voltage-gated calcium channels (VGCCs). Methods: IgG was obtained from 4 patients with LEMS (3 males, 1 female), including 2 patients with lung malignancy. Antibodies against P/Q-type VGCCs were detected in all 4 patients, and against N-type VGCCs in 2. We incubated neuro...

  5. Homocysteine aggravates ROS-induced depression of transmitter release from motor nerve terminals: potential mechanism of peripheral impairment in motor neuron diseases associated with hyperhomocysteinemia

    Directory of Open Access Journals (Sweden)

    Ellya eBukharaeva

    2015-10-01

    Full Text Available Homocysteine (HCY is a pro-inflammatory sulphur-containing redox active endogenous amino acid, which concentration increases in neurodegenerative disorders including amyotrophic lateral sclerosis (ALS. A widely held view suggests that HCY could contribute to neurodegeneration via promotion of oxidative stress. However, the action of HCY on motor nerve terminals has not been investigated so far. We previously reported that oxidative stress inhibited synaptic transmission at the neuromuscular junction, targeting primarily the motor nerve terminals. In the current study, we investigated the effect of HCY on oxidative stress-induced impairment of transmitter release at the mouse diaphragm muscle. The mild oxidant H2O2 decreased the intensity of spontaneous quantum release from nerve terminals (measured as the frequency of miniature endplate potentials, MEPPs without changes in the amplitude of MEPPs, indicating a presynaptic effect. Pre-treatment with HCY for 2 h only slightly affected both amplitude and frequency of MEPPs but increased the inhibitory potency of H2O2 almost two fold. As HCY can activate certain subtypes of glutamate NMDA receptors we tested the role of NMDA receptors in the sensitizing action of HCY. Remarkably, the selective blocker of NMDA receptors, AP-5 completely removed the sensitizing effect of HCY on the H2O2-induced presynaptic depressant effect. Thus, at the mammalian neuromuscular junction HCY largely increases the inhibitory effect of oxidative stress on transmitter release, via NMDA receptors activation. This combined effect of HCY and local oxidative stress can specifically contribute to the damage of presynaptic terminals in neurodegenerative motoneuron diseases, including ALS.

  6. Acid-Sensing Ion Channels Activated by Evoked Released Protons Modulate Synaptic Transmission at the Mouse Calyx of Held Synapse.

    Science.gov (United States)

    González-Inchauspe, Carlota; Urbano, Francisco J; Di Guilmi, Mariano N; Uchitel, Osvaldo D

    2017-03-08

    (coreleased with neurotransmitter from acidified synaptic vesicles). These ASIC-1as contribute to the generation of postsynaptic currents and, more relevant, to calcium influx, which could be involved in the modulation of presynaptic transmitter release. Inhibition or deletion of ASIC-1a leads to enhanced short-term depression, demonstrating that they are concerned with short-term plasticity of the synapse. ASICs represent a widespread communication system with unique properties. We expect that our experiments will have an impact in the neurobiology field and will spread in areas related to neuronal plasticity. Copyright © 2017 the authors 0270-6474/17/372589-11$15.00/0.

  7. Adrenaline release evokes hyperpnoea and an increase in ventilatory CO2 sensitivity during hypoglycaemia: a role for the carotid body.

    Science.gov (United States)

    Thompson, Emma L; Ray, Clare J; Holmes, Andrew P; Pye, Richard L; Wyatt, Christopher N; Coney, Andrew M; Kumar, Prem

    2016-08-01

    Hypoglycaemia is counteracted by release of hormones and an increase in ventilation and CO2 sensitivity to restore blood glucose levels and prevent a fall in blood pH. The full counter-regulatory response and an appropriate increase in ventilation is dependent on carotid body stimulation. We show that the hypoglycaemia-induced increase in ventilation and CO2 sensitivity is abolished by preventing adrenaline release or blocking its receptors. Physiological levels of adrenaline mimicked the effect of hypoglycaemia on ventilation and CO2 sensitivity. These results suggest that adrenaline, rather than low glucose, is an adequate stimulus for the carotid body-mediated changes in ventilation and CO2 sensitivity during hypoglycaemia to prevent a serious acidosis in poorly controlled diabetes. Hypoglycaemia in vivo induces a counter-regulatory response that involves the release of hormones to restore blood glucose levels. Concomitantly, hypoglycaemia evokes a carotid body-mediated hyperpnoea that maintains arterial CO2 levels and prevents respiratory acidosis in the face of increased metabolism. It is unclear whether the carotid body is directly stimulated by low glucose or by a counter-regulatory hormone such as adrenaline. Minute ventilation was recorded during infusion of insulin-induced hypoglycaemia (8-17 mIU kg(-1)  min(-1) ) in Alfaxan-anaesthetised male Wistar rats. Hypoglycaemia significantly augmented minute ventilation (123 ± 4 to 143 ± 7 ml min(-1) ) and CO2 sensitivity (3.3 ± 0.3 to 4.4 ± 0.4 ml min(-1)  mmHg(-1) ). These effects were abolished by either β-adrenoreceptor blockade with propranolol or adrenalectomy. In this hypermetabolic, hypoglycaemic state, propranolol stimulated a rise in P aC O2, suggestive of a ventilation-metabolism mismatch. Infusion of adrenaline (1 μg kg(-1)  min(-1) ) increased minute ventilation (145 ± 4 to 173 ± 5 ml min(-1) ) without altering P aC O2 or pH and enhanced ventilatory CO2 sensitivity (3

  8. Localized infusions of the partial alpha 7 nicotinic receptor agonist SSR180711 evoke rapid and transient increases in prefrontal glutamate release

    DEFF Research Database (Denmark)

    Bortz, D M; Mikkelsen, J D; Bruno, J P

    2013-01-01

    that inhibited (threo-beta-benzyl-oxy-aspartate (TβOA), 100.0μM) or facilitated (ceftriaxalone, 200mg/kg, i.p.) excitatory amino acid transporters. TβOA slowed both the clearance (s) and rate of clearance (μM/s) by 10-fold, particularly at the mid-late stages of the return to baseline. Ceftriaxone reduced......The ability of local infusions of the alpha 7 nicotinic acetycholine receptor (α7 nAChR) partial agonist SSR180711 to evoke glutamate release in prefrontal cortex was determined in awake rats using a microelectrode array. Infusions of SSR180711 produced dose-dependent increases in glutamate levels...

  9. Serotonin release evoked by tail nerve stimulation in the CNS of aplysia: characterization and relationship to heterosynaptic plasticity.

    Science.gov (United States)

    Marinesco, Stephane; Carew, Thomas J

    2002-03-15

    Considerable experimental evidence suggests that serotonin (5-HT) at sensory neuron-->motor neuron (SN-->MN) synapses, as well as other neuronal sites, contributes importantly to simple forms of learning such as sensitization and classical conditioning in Aplysia. However, the actual release of 5-HT in the CNS induced by sensitizing stimuli such as tail shock has not been directly demonstrated. In this study, we addressed this question by (1) immunohistochemically labeling central 5-HT processes and (2) directly measuring with chronoamperometry the release of 5-HT induced by pedal tail nerve (P9) shock onto tail SNs in the pleural ganglion and their synapses onto tail MNs in the pedal ganglion. We found that numerous 5-HT-immunoreactive fibers surround both the SN cell bodies in the pleural ganglion and SN axons in the pedal ganglion. Chronoamperometric detection of 5-HT performed with carbon fiber electrodes implanted in the vicinity of tail SN somata and synapses revealed an electrochemical 5-HT signal lasting approximately 40 sec after a brief shock of P9. 5-HT release was restricted to discrete subregions (modulatory fields) of the CNS, including the vicinity of tail SN soma and synapses ipsilateral to the stimulation. Increasing P9 shock frequency augmented the amplitude of the 5-HT signal and, in parallel, increased SN excitability and SN synaptic transmission onto tail MNs. However, the relationship between the amount of 5-HT release and the two forms of SN plasticity was not uniform: SN excitability increased in a graded manner with increased 5-HT release, whereas synaptic facilitation exhibited a highly nonlinear relationship. The development of chronoamperometric techniques in Aplysia now paves the way for a more complete understanding of the contribution of the serotonergic modulatory pathway to memory processing in this system.

  10. Methyllycaconitine (MLA) blocks the nicotine evoked anxiogenic effect and 5-HT release in the dorsal hippocampus: possible role of alpha7 receptors.

    Science.gov (United States)

    Tucci, S A; Genn, R F; File, S E

    2003-03-01

    Nicotine has bimodal effects on anxiety, with low doses having an anxiolytic effect and high doses having an anxiogenic effect. The dorsal hippocampus is one of the brain areas that mediate the anxiogenic effect of nicotine through enhanced 5-HT release, but the nAChR subtype(s) that mediate these effects are not known. Intrahippocampal administration of a high dose of nicotine (1 micro g, 4.3 mM) had an anxiogenic effect in the social interaction test that was reversed by co-administration of a behaviourally inactive dose (1.9 ng, 4.3 micro M) of methyllycaconitine (MLA), which is an antagonist at alpha7 and alpha3 nAChR subunits. At a dose (0.8 ng, 4.3 micro ;M) at which its actions would be specific to alpha4beta2 and alpha3beta2 nAChRs dihydro-beta-erythroidine (DHbetaE) was unable to reverse nicotine's anxiogenic effect. Reversal was obtained with a 10-fold higher, but receptor non-specific concentration of DHbetaE (7.8ng, 43 micro M), suggesting that the DHbetaE reversal might have been due to action at alpha7 nAChRs. Exposure of hippocampal slices to MLA (0.25, 05, 1 and 10 micro M) significantly reduced the increase in [(3)H]5-HT release evoked by nicotine (100 micro M). DHbetaE (0.1-0.5 micro M) failed to reverse this effect of nicotine on [(3)H]5-HT release, although higher concentrations (1 and 10 micro M), at which alpha7 subunits would also be affected, were able to do so. Because of the lack of effects of low, receptor specific concentrations of DHbetaE, it is more likely that the MLA reversal of both nicotine's anxiogenic effect and its stimulation of [(3)H]5-HT release is due to action at alpha7 than at alpha3 units. This is perhaps also more likely because the alpha7 receptors are highly expressed in the dorsal hippocampus, whereas the alpha3 subunits are much less abundant. However, what is most important is that, in the dorsal hippocampus, nicotine's anxiogenic effect and induced release of [(3)H]5-HT are mediated by non alpha4beta2 nAChRs, which

  11. G-protein coupled receptor-evoked glutamate exocytosis from astrocytes: role of prostaglandins.

    Science.gov (United States)

    Cali, Corrado; Lopatar, Jan; Petrelli, Francesco; Pucci, Luca; Bezzi, Paola

    2014-01-01

    Astrocytes are highly secretory cells, participating in rapid brain communication by releasing glutamate. Recent evidences have suggested that this process is largely mediated by Ca(2+)-dependent regulated exocytosis of VGLUT-positive vesicles. Here by taking advantage of VGLUT1-pHluorin and TIRF illumination, we characterized mechanisms of glutamate exocytosis evoked by endogenous transmitters (glutamate and ATP), which are known to stimulate Ca(2+) elevations in astrocytes. At first we characterized the VGLUT1-pHluorin expressing vesicles and found that VGLUT1-positive vesicles were a specific population of small synaptic-like microvesicles containing glutamate but which do not express VGLUT2. Endogenous mediators evoked a burst of exocytosis through activation of G-protein coupled receptors. Subsequent glutamate exocytosis was reduced by about 80% upon pharmacological blockade of the prostaglandin-forming enzyme, cyclooxygenase. On the other hand, receptor stimulation was accompanied by extracellular release of prostaglandin E2 (PGE2). Interestingly, administration of exogenous PGE2 produced per se rapid, store-dependent burst exocytosis of glutamatergic vesicles in astrocytes. Finally, when PGE2-neutralizing antibody was added to cell medium, transmitter-evoked exocytosis was again significantly reduced (by about 50%). Overall these data indicate that cyclooxygenase products are responsible for a major component of glutamate exocytosis in astrocytes and that large part of such component is sustained by autocrine/paracrine action of PGE2.

  12. G-Protein Coupled Receptor-Evoked Glutamate Exocytosis from Astrocytes: Role of Prostaglandins

    Directory of Open Access Journals (Sweden)

    Corrado Cali

    2014-01-01

    Full Text Available Astrocytes are highly secretory cells, participating in rapid brain communication by releasing glutamate. Recent evidences have suggested that this process is largely mediated by Ca2+-dependent regulated exocytosis of VGLUT-positive vesicles. Here by taking advantage of VGLUT1-pHluorin and TIRF illumination, we characterized mechanisms of glutamate exocytosis evoked by endogenous transmitters (glutamate and ATP, which are known to stimulate Ca2+ elevations in astrocytes. At first we characterized the VGLUT1-pHluorin expressing vesicles and found that VGLUT1-positive vesicles were a specific population of small synaptic-like microvesicles containing glutamate but which do not express VGLUT2. Endogenous mediators evoked a burst of exocytosis through activation of G-protein coupled receptors. Subsequent glutamate exocytosis was reduced by about 80% upon pharmacological blockade of the prostaglandin-forming enzyme, cyclooxygenase. On the other hand, receptor stimulation was accompanied by extracellular release of prostaglandin E2 (PGE2. Interestingly, administration of exogenous PGE2 produced per se rapid, store-dependent burst exocytosis of glutamatergic vesicles in astrocytes. Finally, when PGE2-neutralizing antibody was added to cell medium, transmitter-evoked exocytosis was again significantly reduced (by about 50%. Overall these data indicate that cyclooxygenase products are responsible for a major component of glutamate exocytosis in astrocytes and that large part of such component is sustained by autocrine/paracrine action of PGE2.

  13. Phencyclidine (PCP)-like inhibition of N-methyl-D-aspartate-evoked striatal acetylcholine release, /sup 3/H-TCP binding and synaptosomal dopamine uptake by metaphit, a proposed PCP receptor acylator

    Energy Technology Data Exchange (ETDEWEB)

    Snell, L.D.; Johnson, K.M.; Yi, S.J.; Lessor, R.A.; Rice, K.C.; Jacobson, A.E.

    1987-12-14

    The phencyclidine (PCP) receptor acylator, metaphit, has been reported to act as a PCP antagonist. Recent electrophysiological and behavioral assessments of metaphit action have revealed, however, that this compound can also act as a PCP-like agonist. The present study examined the effects of metaphit on the inhibition of N-methyl-D-aspartate (NMDA)-induced /sup 3/H-acetylcholine (ACh) release, /sup 3/H-TCP binding and synaptosomal /sup 3/H-dopamine (DA) uptake in the rat striatum. Preincubation of striatal slices for 10 min in the presence of metaphit, followed by a prolonged washout, produced a concentration-dependent inhibition of the ACh release evoked by 300 ..mu..M NMDA. At high concentrations, preincubation with PCP also resulted in inhibition of this measure. However, this could be reduced by extending the washout period, a procedure which had no effect on the inhibition produced by metaphit. At 10..mu..M, metaphit resulted in a 53% reduction in NMDA-evoked ACh release while PCP had no effect under identical conditions. Preincubation of slices in 10 ..mu..M PCP and metaphit reduced the metaphit inhibition by 62%. The effects of PCP and metaphit, alone or in combination, on NMDA-induced ACh release were paralleled by a loss of /sup 3/H-TCP binding sites in striatal tissue incubated under identical conditions suggesting that metaphit exerts long-lasting agonist-like actions on PCP receptors coupled to NMDA receptors. 27 references, 3 figures, 1 table.

  14. Prostaglandin E2 Inhibits Histamine-Evoked Ca2+ Release in Human Aortic Smooth Muscle Cells through Hyperactive cAMP Signaling Junctions and Protein Kinase A.

    Science.gov (United States)

    Taylor, Emily J A; Pantazaka, Evangelia; Shelley, Kathryn L; Taylor, Colin W

    2017-11-01

    In human aortic smooth muscle cells, prostaglandin E2 (PGE2) stimulates adenylyl cyclase (AC) and attenuates the increase in intracellular free Ca2+ concentration evoked by activation of histamine H1 receptors. The mechanisms are not resolved. We show that cAMP mediates inhibition of histamine-evoked Ca2+ signals by PGE2 Exchange proteins activated by cAMP were not required, but the effects were attenuated by inhibition of cAMP-dependent protein kinase (PKA). PGE2 had no effect on the Ca2+ signals evoked by protease-activated receptors, heterologously expressed muscarinic M3 receptors, or by direct activation of inositol 1,4,5-trisphosphate (IP3) receptors by photolysis of caged IP3 The rate of Ca2+ removal from the cytosol was unaffected by PGE2, but PGE2 attenuated histamine-evoked IP3 accumulation. Substantial inhibition of AC had no effect on the concentration-dependent inhibition of Ca2+ signals by PGE2 or butaprost (to activate EP2 receptors selectively), but it modestly attenuated responses to EP4 receptors, activation of which generated less cAMP than EP2 receptors. We conclude that inhibition of histamine-evoked Ca2+ signals by PGE2 occurs through "hyperactive signaling junctions," wherein cAMP is locally delivered to PKA at supersaturating concentrations to cause uncoupling of H1 receptors from phospholipase C. This sequence allows digital signaling from PGE2 receptors, through cAMP and PKA, to histamine-evoked Ca2+ signals. Copyright © 2017 by The Author(s).

  15. Spectral transmittance reference standards

    Energy Technology Data Exchange (ETDEWEB)

    Kruglyakova, M.A.; Belyaeva, O.N.; Nikitin, M.V.

    1995-06-01

    This paper presents spectral transmittance reference standards for UV and IR spectrophotometers, developed, studied, and certified by a precision spectrophotometry laboratory (the RSP Complex). 8 refs., 3 figs., 3 tabs.

  16. Neuromuscular paralysis by the basic phospholipase A2subunit of crotoxin from Crotalus durissus terrificus snake venom needs its acid chaperone to concurrently inhibit acetylcholine release and produce muscle blockage.

    Science.gov (United States)

    Cavalcante, Walter L G; Noronha-Matos, José B; Timóteo, Maria A; Fontes, Marcos R M; Gallacci, Márcia; Correia-de-Sá, Paulo

    2017-11-01

    Crotoxin (CTX), a heterodimeric phospholipase A 2 (PLA 2 ) neurotoxin from Crotalus durissus terrificus snake venom, promotes irreversible blockade of neuromuscular transmission. Indirect electrophysiological evidence suggests that CTX exerts a primary inhibitory action on transmitter exocytosis, yet contribution of a postsynaptic action of the toxin resulting from nicotinic receptor desensitization cannot be excluded. Here, we examined the blocking effect of CTX on nerve-evoked transmitter release measured directly using radioisotope neurochemistry and video microscopy with the FM4-64 fluorescent dye. Experiments were conducted using mice phrenic-diaphragm preparations. Real-time fluorescence video microscopy and liquid scintillation spectrometry techniques were used to detect transmitter exocytosis and nerve-evoked [ 3 H]-acetylcholine ([ 3 H]ACh) release, respectively. Nerve-evoked myographic recordings were also carried out for comparison purposes. Both CTX (5μg/mL) and its basic PLA 2 subunit (CB, 20μg/mL) had biphasic effects on nerve-evoked transmitter exocytosis characterized by a transient initial facilitation followed by a sustained decay. CTX and CB reduced nerve-evoked [ 3 H]ACh release by 60% and 69%, respectively, but only the heterodimer, CTX, decreased the amplitude of nerve-evoked muscle twitches. Data show that CTX exerts a presynaptic inhibitory action on ACh release that is highly dependent on its intrinsic PLA 2 activity. Given the high safety margin of the neuromuscular transmission, one may argue that the presynaptic block caused by the toxin is not enough to produce muscle paralysis unless a concurrent postsynaptic inhibitory action is also exerted by the CTX heterodimer. Copyright © 2017. Published by Elsevier Inc.

  17. Kappa opioid receptor activation potentiates the cocaine-induced increase in evoked dopamine release recorded in vivo in the mouse nucleus accumbens

    National Research Council Canada - National Science Library

    Ehrich, Jonathan M; Phillips, Paul E M; Chavkin, Charles

    2014-01-01

    .... Prior studies have established that this potentiation of drug reward was mediated by stress-induced release of the endogenous dynorphin opioids and subsequent kappa opioid receptor (KOR) activation...

  18. Knocking out P2X receptors reduces transmitter secretion in taste buds

    Science.gov (United States)

    Huang, Yijen A.; Stone, Leslie M.; Pereira, Elizabeth; Yang, Ruibiao; Kinnamon, John C.; Dvoryanchikov, Gennady; Chaudhari, Nirupa; Finger, Thomas E.; Kinnamon, Sue C.; Roper, Stephen D.

    2011-01-01

    In response to gustatory stimulation, taste bud cells release a transmitter, ATP, that activates P2X2 and P2X3 receptors on gustatory afferent fibers. Taste behavior and gustatory neural responses are largely abolished in mice lacking P2X2 and P2X3 receptors (P2X2 and P2X3 double knockout, or “DKO” mice). The assumption has been that eliminating P2X2 and P2X3 receptors only removes postsynaptic targets but that transmitter secretion in mice is normal. Using functional imaging, ATP biosensor cells, and a cell-free assay for ATP, we tested this assumption. Surprisingly, although gustatory stimulation mobilizes Ca2+ in taste Receptor (Type II) cells from DKO mice, as from wild type (WT) mice, taste cells from DKO mice fail to release ATP when stimulated with tastants. ATP release could be elicited by depolarizing DKO Receptor cells with KCl, suggesting that ATP-release machinery remains functional in DKO taste buds. To explore the difference in ATP release across genotypes, we employed reverse transcriptase (RT)-PCR, immunostaining, and histochemistry for key proteins underlying ATP secretion and degradation: Pannexin1, TRPM5, and NTPDase2 (ecto-ATPase) are indistinguishable between WT and DKO mice. The ultrastructure of contacts between taste cells and nerve fibers is also normal in the DKO mice. Finally, quantitative RT-PCR show that P2X4 and P2X7, potential modulators of ATP secretion, are similarly expressed in taste buds in WT and DKO taste buds. Importantly, we find that P2X2 is expressed in WT taste buds and appears to function as an autocrine, positive feedback signal to amplify taste-evoked ATP secretion. PMID:21940456

  19. Distributed data transmitter

    Science.gov (United States)

    Brown, Kenneth Dewayne [Grain Valley, MO; Dunson, David [Kansas City, MO

    2008-06-03

    A distributed data transmitter (DTXR) which is an adaptive data communication microwave transmitter having a distributable architecture of modular components, and which incorporates both digital and microwave technology to provide substantial improvements in physical and operational flexibility. The DTXR has application in, for example, remote data acquisition involving the transmission of telemetry data across a wireless link, wherein the DTXR is integrated into and utilizes available space within a system (e.g., a flight vehicle). In a preferred embodiment, the DTXR broadly comprises a plurality of input interfaces; a data modulator; a power amplifier; and a power converter, all of which are modularly separate and distinct so as to be substantially independently physically distributable and positionable throughout the system wherever sufficient space is available.

  20. Detecting a dexmedetomidine-evoked reduction of noradrenaline release in the human brain with the alpha2C-adrenoceptor PET ligand [11C]ORM-13070.

    Science.gov (United States)

    Lehto, Jussi; Scheinin, Annalotta; Johansson, Jarkko; Marjamäki, Päivi; Arponen, Eveliina; Scheinin, Harry; Scheinin, Mika

    2016-02-01

    PET imaging can for some neurotransmitters be used to measure synaptic neurotransmitter concentrations. The objective of this study was to test whether the receptor binding of the α2C -AR antagonist PET tracer [(11)C]ORM-13070 would increase in response to reductions in synaptic noradrenaline, evoked by dexmedetomidine as a sympatholytic drug challenge. Six subjects underwent a control PET scan and two dexmedetomidine PET scans. Dexmedetomidine was infused with target plasma concentrations of 0.6 and 0.2 ng/ml. Tracer binding was measured by voxel-based analysis of bound per free (B/F) images. ROI-based analysis was performed in the dorsal striatum and in the thalamus. Vital signs and drug concentrations in plasma were measured and the sedative effect was estimated with the visual analog scale. In the voxel-based analysis, dexmedetomidine administration was associated with a tendency to increased B/F tracer in the right thalamus (mean, +17%, P = 0.14, and +19%, P = 0.05, with the low and high dose, respectively). Tracer binding in the dorsal striatum was unaffected by dexmedetomidine. A cluster with significantly increased B/F tracer (+42%, P = 0.01) was seen in the right superior temporal gyrus with low-dose dexmedetomidine, but not after the high dose. Brain uptake of [(11)C]ORM-13070 has previously been shown to be reduced in conditions of increased synaptic noradrenaline concentrations. In this study, tracer binding in the thalamus tended to increase in accordance with reduced activity of noradrenergic projections from the locus coeruleus, but statistical significance was not reached. © 2015 Wiley Periodicals, Inc.

  1. Single versus multiple impulse control disorders in Parkinson's disease: an ¹¹C-raclopride positron emission tomography study of reward cue-evoked striatal dopamine release.

    Science.gov (United States)

    Wu, Kit; Politis, Marios; O'Sullivan, Sean S; Lawrence, Andrew D; Warsi, Sarah; Bose, Subrata; Lees, Andrew J; Piccini, Paola

    2015-06-01

    Impulse control disorders (ICDs) are reported in Parkinson's disease (PD) in association with dopaminergic treatment. Approximately 25 % of patients with ICDs have multiple co-occurring ICDs (i.e. more than one diagnosed ICD). The extent to which dopaminergic neurotransmission in PD patients with multiple ICDs differs from those with only one diagnosed ICD is unknown. The aims of this study are: (1) to investigate dopamine neurotransmission in PD patients diagnosed with multiple ICDs, single ICDs and non-ICD controls in response to reward-related visual cues using positron emission tomography with (11)C-raclopride. (2) to compare clinical features of the above three groups. PD individuals with mulitple ICDs (n = 10), single ICD (n = 7) and no ICDs (n = 9) were recruited and underwent two positron emission tomography (PET) scans with (11)C-raclopride: one where they viewed neutral visual cues and the other where they viewed a range of visual cues related to different rewards. Individuals with both multiple ICDs and single ICDs showed significantly greater ventral striatal dopamine release compared to non-ICD PD individuals in response to reward cues, but the two ICD groups did not differ from each other in the extent of dopamine release. Subjects with multiple ICDs were, however, significantly more depressed, and had higher levels of impulsive sensation-seeking compared to subjects with single ICDs and without ICDs. This is the first study to compare dopamine neurotransmission using PET neuroimaging in PD subjects with multiple vs. single ICDs. Our results suggest that striatal dopamine neurotransmission is not directly related to the co-occurrence of ICDs in PD, potentially implicating non-dopaminergic mechanisms linked to depression; and suggest that physicians should be vigilant in managing depression in PD patients with ICDs.

  2. Interconnects, Transmitters, and Receivers

    Science.gov (United States)

    Hoefflinger, Bernd

    Interconnects on-chip between transistors and between functions like processors and memories, between chips on carriers or in stacks, and the communication with the outside world have become a highly complex performance, reliability, cost, and energy challenge. Twelve layers of metal interconnects, produced by lithography, require, including the contact vias, 24 mask and process cycles on top of the process front-end. The resulting lines are associated with resistance, capacitance and inductance parasitics as well as with ageing due to high current densities. Large savings in wiring lengths are achieved with 3D integration: transistor stacking, chip stacking and TSV's, a direction, which has exploded since 2005 because of many other benefits and, at the same time, with sensitive reliability and cost issues. On top of this or as an alternative, non-contact interconnects are possible with capacitive or inductive coupling. Inductive in particular has proven to be attractive because its transmission range is large enough for communication in chip stacks and yet not too large to cause interference.Optical transmitters based on integrated III-V compound-semiconductor lasers and THz power amplifiers compete with ascending low-cost, parallel-wire transmitters based on BiCMOS technologies. Parallel mm-wave and THz transceiver arrays enable mm-wave radar for traffic safety and THz computed-tomography. In spite of all these technology advances, the power efficiency of data communication will only improve 100× in a decade. New compression and architectural techniques are in high demand.

  3. 47 CFR 74.461 - Transmitter power.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Transmitter power. 74.461 Section 74.461....461 Transmitter power. (a) Transmitter power is the power at the transmitter output terminals and.... For the purpose of this Subpart, the transmitter power is the carrier power. (b) The authorized...

  4. Sleep-wake sensitive mechanisms of adenosine release in the basal forebrain of rodents: an in vitro study.

    Directory of Open Access Journals (Sweden)

    Robert Edward Sims

    Full Text Available Adenosine acting in the basal forebrain is a key mediator of sleep homeostasis. Extracellular adenosine concentrations increase during wakefulness, especially during prolonged wakefulness and lead to increased sleep pressure and subsequent rebound sleep. The release of endogenous adenosine during the sleep-wake cycle has mainly been studied in vivo with microdialysis techniques. The biochemical changes that accompany sleep-wake status may be preserved in vitro. We have therefore used adenosine-sensitive biosensors in slices of the basal forebrain (BFB to study both depolarization-evoked adenosine release and the steady state adenosine tone in rats, mice and hamsters. Adenosine release was evoked by high K(+, AMPA, NMDA and mGlu receptor agonists, but not by other transmitters associated with wakefulness such as orexin, histamine or neurotensin. Evoked and basal adenosine release in the BFB in vitro exhibited three key features: the magnitude of each varied systematically with the diurnal time at which the animal was sacrificed; sleep deprivation prior to sacrifice greatly increased both evoked adenosine release and the basal tone; and the enhancement of evoked adenosine release and basal tone resulting from sleep deprivation was reversed by the inducible nitric oxide synthase (iNOS inhibitor, 1400 W. These data indicate that characteristics of adenosine release recorded in the BFB in vitro reflect those that have been linked in vivo to the homeostatic control of sleep. Our results provide methodologically independent support for a key role for induction of iNOS as a trigger for enhanced adenosine release following sleep deprivation and suggest that this induction may constitute a biochemical memory of this state.

  5. Sleep-Wake Sensitive Mechanisms of Adenosine Release in the Basal Forebrain of Rodents: An In Vitro Study

    Science.gov (United States)

    Sims, Robert Edward; Wu, Houdini Ho Tin; Dale, Nicholas

    2013-01-01

    Adenosine acting in the basal forebrain is a key mediator of sleep homeostasis. Extracellular adenosine concentrations increase during wakefulness, especially during prolonged wakefulness and lead to increased sleep pressure and subsequent rebound sleep. The release of endogenous adenosine during the sleep-wake cycle has mainly been studied in vivo with microdialysis techniques. The biochemical changes that accompany sleep-wake status may be preserved in vitro. We have therefore used adenosine-sensitive biosensors in slices of the basal forebrain (BFB) to study both depolarization-evoked adenosine release and the steady state adenosine tone in rats, mice and hamsters. Adenosine release was evoked by high K+, AMPA, NMDA and mGlu receptor agonists, but not by other transmitters associated with wakefulness such as orexin, histamine or neurotensin. Evoked and basal adenosine release in the BFB in vitro exhibited three key features: the magnitude of each varied systematically with the diurnal time at which the animal was sacrificed; sleep deprivation prior to sacrifice greatly increased both evoked adenosine release and the basal tone; and the enhancement of evoked adenosine release and basal tone resulting from sleep deprivation was reversed by the inducible nitric oxide synthase (iNOS) inhibitor, 1400 W. These data indicate that characteristics of adenosine release recorded in the BFB in vitro reflect those that have been linked in vivo to the homeostatic control of sleep. Our results provide methodologically independent support for a key role for induction of iNOS as a trigger for enhanced adenosine release following sleep deprivation and suggest that this induction may constitute a biochemical memory of this state. PMID:23326515

  6. Optical transmittance of multilayer graphene

    Science.gov (United States)

    Zhu, Shou-En; Yuan, Shengjun; Janssen, G. C. A. M.

    2014-10-01

    We study the optical transmittance of multilayer graphene films up to 65 layers thick. By combing large-scale tight-binding simulation and optical measurement on CVD multilayer graphene, the optical transmission through graphene films in the visible region is found to be solely determined by the number of graphene layers. We argue that the optical transmittance measurement is more reliable in the determination of the number of layers than the commonly used the Raman spectroscopy. Moreover, the optical transmittance measurement can be applied also to other 2D materials with weak van der Waals interlayer interaction.

  7. Evoked cavernous activity.

    Science.gov (United States)

    Yilmaz, Uğur; Soylu, Ahmet; Ozcan, Cemal; Kutlu, Ramazan; Güneş, Ali

    2002-01-01

    Corpus cavernosum electromyography has been widely done to evaluate autonomic dysfunction in patients with erectile dysfunction. We assessed the value of corpus cavernosum electromyography, evoked cavernous activity and penile sympathetic skin responses for their accuracy in determining autonomic involvement in cases of erectile dysfunction. We evaluated 75 men with erectile dysfunction by corpus cavernosum electromyography, evoked cavernous activity and penile sympathetic skin response tests at our neurourology laboratory. The etiology of dysfunction was vascular, neurogenic, psychogenic or mixed based on a detailed medical and sexual history, physical examination, electrophysiological and laboratory studies, penile color Doppler ultrasonography, and cavernosography and/or cavernosometry. Autonomic involvement was clinically assessed by systemic findings, such as orthostatic hypotension, impaired gastrointestinal motility, sinus dysrhythmia and secretomotor changes. A concentric electromyography needle placed in the right cavernous body was used to record corpus cavernosum electromyography and evoked cavernous activity. The right median nerve was stimulated electrically with 13 to 16 mA. to determine evoked cavernous activity and the penile sympathetic skin response. The latter response was recorded with silver disc electrodes placed on the left cavernous body. All tests were performed using an electromyography/evoked potential machine. We determined the relationships among corpus cavernosum electromyography, evoked cavernous activity and penile sympathetic skin response tests in respect to etiological factors. The 56 patients with normal corpus cavernosum electromyography activity had also evoked cavernous activity and a penile sympathetic skin response except for 1 with no penile sympathetic skin response but evoked cavernous activity. None of these patients had autonomic neuropathy. Of the 19 patients without corpus cavernosum electromyography activity 11 had

  8. Transmittance measurement using scanning LED

    Science.gov (United States)

    Ping, Yao; Mohan, Rosmin Elsa; Lau, Gih-Keong; Asundi, Anand Krishna

    2017-06-01

    In order to measure the transmittance for a large field of view (FOV), a system based on scanning LED is developed. The system mainly consists of tunable LEDs, a glass diffuser and a camera. The LED panel would display different colors in the CIE color space. An algorithm of converting the light wavelength to the RGB values is adopted. The images are captured using a monochrome camera. Depending on the number of colors displayed, the transmittance map for the entire spread of visible colors can be determined. Results are compared with those measured through a spectrometer. The spectral transmittance for the two methods exhibit good similarity. The system provides a means of measuring transmittance with no moving parts and can be extended to other hyperspectral imaging applications.

  9. In inflammatory reactive astrocytes co-cultured with brain endothelial cells nicotine-evoked Ca(2+) transients are attenuated due to interleukin-1beta release and rearrangement of actin filaments.

    Science.gov (United States)

    Delbro, D; Westerlund, A; Björklund, U; Hansson, E

    2009-03-17

    The aim of this study was to investigate whether nicotine acetylcholine receptors (nAChRs) are expressed in a more pronounced way in astrocytes co-cultured with microvascular endothelial cells from adult rat brain, compared with monocultured astrocytes, as a sign of a more developed signal transduction system. Also investigated was whether nicotine plays a role in the control of neuroinflammatory reactivity in astrocytes. Ca(2+) imaging experiments were performed using cells loaded with the Ca(2+) indicator Fura-2/AM. Co-cultured astrocytes responded to lower concentrations of nicotine than did monocultured astrocytes, indicating that they are more sensitive to nicotine. Co-cultured astrocytes also expressed a higher selectivity for alpha7nAChR and alpha4/beta2 subunits and evoked higher Ca(2+) transients compared with monocultured astrocytes. The Ca(2+) transients referred to are activators of Ca(2+)-induced Ca(2+) release from intracellular stores, both IP(3) and ryanodine, triggered by influx through receptor channels. The nicotine-induced Ca(2+) transients were attenuated after incubation with the inflammatory mediator lipopolysaccharide (LPS), but were not attenuated after incubation with the pain-transmitting peptides substance P and calcitonin-gene-related peptide, nor with the infection and inflammation stress mediator, leptin. Furthermore, LPS-induced release of interleukin-1beta (IL-1beta) measured by enzyme-linked immunosorbent assay (ELISA) was more pronounced in co-cultured versus monocultured astrocytes. Incubation with both LPS and IL-1beta further attenuated nicotine-induced Ca(2+) response. We also found that LPS and IL-1beta induced rearrangement of the F-actin filaments, as measured with an Alexa488-conjugated phalloidin probe. The rearrangements consisted of increases in ring formations and a more dispersed appearance of the filaments. These results indicate that there is a connection between a dysfunction of nicotine Ca(2+) signaling in

  10. Optical transmittance of multilayer graphene

    OpenAIRE

    Zhu, Shou-En; Yuan, Shengjun; Janssen, G.C.A.M.

    2014-01-01

    We study the optical transmittance of multilayer graphene films up to 65 layers thick. By combing large-scale tight-binding simulation and optical measurement on CVD multilayer graphene, the optical transmission through graphene films in the visible region is found to be solely determined by the number of graphene layers. We argue that the optical transmittance measurement is more reliable in the determination of the number of layers than the commonly used Raman Spectroscopy. Moreover, optica...

  11. Evaluation of acoustic transmitter implantation and determination of ...

    African Journals Online (AJOL)

    Largemouth bass Micropterus salmoides are an important angling species that are often displaced during catchand-release fishing tournaments. The impact of acoustic transmitter implantation on this species and the effect of displacement distance on their behaviour were tested. In April 2010, 10 fish with surgically ...

  12. Proprioceptive evoked gamma oscillations

    DEFF Research Database (Denmark)

    Arnfred, S.M.; Hansen, Lars Kai; Parnas, J.

    2007-01-01

    A proprioceptive stimulus consisting of a weight change of a handheld load has recently been shown to elicit an evoked potential. Previously, somatosensory gamma oscillations have only been evoked by electrical stimuli. We conjectured that a natural proprioceptive stimulus also would be able...... to evoke gamma oscillations. EEG was recorded using 64 channels in 14 healthy subjects. In each of three runs a stimulus of 100 g load increment in each hand was presented in 120 trials. Data were wavelet transformed and runs collapsed. Inter-trial phase coherence (ITPC) was computed as the best measure...... contralateral to stimulus side and additionally an unexpected 20 Hz activity was observed slightly lateralized in the frontal central region. The gamma phase locking may be a manifestation of early somatosensory feature integration. The analyses suggest that the high frequency activity consists of two distinct...

  13. Evoked acoustic emission

    DEFF Research Database (Denmark)

    Elberling, C; Parbo, J; Johnsen, N J

    1985-01-01

    Stimulated acoustic emissions were recorded in response to tonal stimuli at 60 dB p.e. SPL in a small group of normal-hearing adults. Power spectral analysis reveals that the evoked activity from each ear contains energy in preferential frequency bands and the change of stimulus frequency has only...

  14. Proprioceptive evoked gamma oscillations

    DEFF Research Database (Denmark)

    Arnfred, Sidse M; Hansen, Lars Kai; Parnas, Josef

    2007-01-01

    to evoke gamma oscillations. EEG was recorded using 64 channels in 14 healthy subjects. In each of three runs a stimulus of 100 g load increment in each hand was presented in 120 trials. Data were wavelet transformed and runs collapsed. Inter-trial phase coherence (ITPC) was computed as the best measure...

  15. BAER - brainstem auditory evoked response

    Science.gov (United States)

    ... auditory potentials; Brainstem auditory evoked potentials; Evoked response audiometry; Auditory brainstem response; ABR; BAEP ... Normal results vary. Results will depend on the person and the instruments used to perform the test.

  16. Purines released from astrocytes inhibit excitatory synaptic transmission in the ventral horn of the spinal cord

    DEFF Research Database (Denmark)

    Carlsen, Eva Maria Meier; Perrier, Jean-Francois Marie

    2014-01-01

    Spinal neuronal networks are essential for motor function. They are involved in the integration of sensory inputs and the generation of rhythmic motor outputs. They continuously adapt their activity to the internal state of the organism and to the environment. This plasticity can be provided...... by different neuromodulators. These substances are usually thought of being released by dedicated neurons. However, in other networks from the central nervous system synaptic transmission is also modulated by transmitters released from astrocytes. The star-shaped glial cell responds to neurotransmitters...... by releasing gliotransmitters, which in turn modulate synaptic transmission. Here we investigated if astrocytes present in the ventral horn of the spinal cord modulate synaptic transmission. We evoked synaptic inputs in ventral horn neurons recorded in a slice preparation from the spinal cord of neonatal mice...

  17. 47 CFR 22.657 - Transmitter locations.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Transmitter locations. 22.657 Section 22.657 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES PUBLIC MOBILE SERVICES... effective radiated power (ERP) of the most powerful mobile transmitter(s) in the system: Mobile unit ERP...

  18. 47 CFR 101.513 - Transmitter power.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Transmitter power. 101.513 Section 101.513... SERVICES 24 GHz Service and Digital Electronic Message Service § 101.513 Transmitter power. The transmitter power will be governed by § 101.113. Further, each application must contain an analysis demonstrating...

  19. 47 CFR 80.215 - Transmitter power.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Transmitter power. 80.215 Section 80.215... MARITIME SERVICES General Technical Standards § 80.215 Transmitter power. (a) Transmitter power shown on the radio station authorization is the maximum power the licensee is authorized to use. Power is...

  20. 47 CFR 101.807 - Transmitter power.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Transmitter power. 101.807 Section 101.807... SERVICES Local Television Transmission Service § 101.807 Transmitter power. Stations in this service will not be authorized to use transmitters having a rated power output in excess of the limits set forth in...

  1. Intermittent ATP release from nerve terminals elicits focal smooth muscle Ca2+ transients in mouse vas deferens

    Science.gov (United States)

    Brain, Keith L; Jackson, V Margaret; Trout, Stephen J; Cunnane, Thomas C

    2002-01-01

    A confocal Ca2+ imaging technique has been used to detect ATP release from individual sympathetic varicosities on the same nerve terminal branch. Varicose nerve terminals and smooth muscle cells in mouse vas deferens were loaded with the Ca2+ indicator Oregon Green 488 BAPTA-1. Field (nerve) stimulation evoked discrete, focal increases in [Ca2+] in smooth muscle cells adjacent to identified varicosities. These focal increases in [Ca2+] have been termed ‘neuroeffector Ca2+ transients’ (NCTs). NCTs were abolished by α,β-methylene ATP (1 μM), but not by nifedipine (1 μM) or prazosin (100 nm), suggesting that NCTs are generated by Ca2+ influx through P2X receptors without a detectable contribution from L-type Ca2+ channels or α1-adrenoceptor-mediated pathways. Action potential-evoked ATP release was highly intermittent (mean probability 0.019 ± 0.002; range 0.001-0.10) at 1 Hz stimulation, even though there was no failure of action potential propagation in the nerve terminals. Twenty-eight per cent of varicosities failed to release transmitter following more than 500 stimuli. Spontaneous ATP release was very infrequent (0.0014 Hz). No Ca2+ transient attributable to noradrenaline release was detected even in response to 5 Hz stimulation. There was evidence of local noradrenaline release as the α2-adrenoceptor antagonist yohimbine increased the probability of occurrence of NCTs by 55 ± 21 % during trains of stimuli at 1 Hz. Frequency-dependent facilitation preferentially occurred at low probability release sites. The monitoring of NCTs now allows transmitter release to be detected simultaneously from each functional varicosity on an identified nerve terminal branch on an impulse-to-impulse basis. PMID:12068045

  2. Selecting and evoking innovators

    DEFF Research Database (Denmark)

    Kanstrup, Anne Marie; Christiansen, Ellen

    2006-01-01

    prepared for and conducted selection of and collaboration with innovators. The outcome was successful in the sense that the innovators produced excellent foundation for conceptual interaction design by creating mock-ups and explanations incarnating their preferences, attitudes and habits. By referring...... to theories of learning we try to explain how our way of working with selection and evoking of innovators has contributed to this positive result and how our approach to user-driven innovation can be regarded as a way to combine democracy and creativity in design....

  3. International Evoked Potentials Symposium

    CERN Document Server

    1980-01-01

    The past decade has seen great progress in the measurement of evoked potentials in man; a steady increase in our understanding of their charac­ teristics, their origins and their usefulness; and a growing application in the field of clinical diagnosis. The topic is a truly multidisciplinary one. Important research contributions have been made by workers of many different backgrounds and clinical applications span the specialities. This book represents a revised and updated version of the work originally presented at the international evoked potential symposium held in Nottingham 4-6 1978. The Nottingham Symposium provided a forum for a state-of-the-art discussion amongst workers from many different disciplines and from many different countries. For each major topic in the field an expert review set the scene for discussion of current research presentations. This format is retained in the book: the chapters in Part A provide the context in which the research presented in Part B is set. The task of selecting m...

  4. Radio Transmitter Implantation and Movement in the Wild Timber Rattlesnake ( Crotalus horridus ).

    Science.gov (United States)

    Hale, Vanessa L; MacGowan, Brian; Corriveau, Lorraine; Huse, David C; Currylow, Andrea F T; Thompson, Steve

    2017-07-01

    Radiotelemetry transmitters have become critical to studies of wildlife ecology. However, little is known about how transmitter implantation surgery affects the mobility of some species, including the timber rattlesnake, Crotalus horridus . Tracking snake movement can provide insights into the effects of transmitter implantation. During 2007-11, 71 radio transmitters were surgically implanted intracoelomically in 47 timber rattlesnakes. Over 20 of these snakes underwent surgery at least twice in 5 yr to replace old transmitters. Surgeries were performed under general anesthesia with a local nerve block at the site of implantation, 20 cm cranial to the cloaca. Snakes were also administered postsurgical meloxicam and enrofloxacin every 24 h for three doses. Two to five days after surgery, snakes were released at their original locations and radiotracked regularly during the active seasons (April-October 2007-11). Average daily movement data (distance traveled) were compiled for each snake. Snakes undergoing transmitter surgery in a given year did not differ significantly in distance traveled compared to snakes that had transmitters but did not have surgery in that year. Distance traveled for each snake did not differ before or after surgery or between weeks 1 and 2 postsurgery, indicating that the transmitter implantation did not alter snake movement.

  5. Intraperitoneal implantation of life-long telemetry transmitters in otariids

    Directory of Open Access Journals (Sweden)

    Haulena Martin

    2008-12-01

    Full Text Available Abstract Background Pinnipeds, including many endangered and declining species, are inaccessible and difficult to monitor for extended periods using externally attached telemetry devices that are shed during the annual molt. Archival satellite transmitters were implanted intraperitoneally into four rehabilitated California sea lions (Zalophus californianus and 15 wild juvenile Steller sea lions (Eumetopias jubatus to determine the viability of this surgical technique for the deployment of long-term telemetry devices in otariids. The life history transmitters record information throughout the life of the host and transmit data to orbiting satellites after extrusion following death of the host. Results Surgeries were performed under isoflurane anesthesia and single (n = 4 or dual (n = 15 transmitters were inserted into the ventrocaudal abdominal cavity via an 8.5 to 12 cm incision along the ventral midline between the umbilicus and pubic symphysis or preputial opening. Surgeries lasted 90 minutes (SD = 8 for the 19 sea lions. All animals recovered well and were released into the wild after extended monitoring periods from 27 to 69 days at two captive animal facilities. Minimum post-implant survival was determined via post-release tracking using externally attached satellite transmitters or via opportunistic re-sighting for mean durations of 73.7 days (SE = 9.0, Z. californianus and 223.6 days (SE = 71.5, E. jubatus. Conclusion The low morbidity and zero mortality encountered during captive observation and post-release tracking periods confirm the viability of this surgical technique for the implantation of long-term telemetry devices in otariids.

  6. Vestibular evoked myogenic potential

    Directory of Open Access Journals (Sweden)

    Felipe, Lilian

    2012-01-01

    Full Text Available Introduction: The Vestibular Evoked Myogenic Potential (VEMP is a promising test for the evaluation of the cholic descending vestibular system. This reflex depends of the integrity from the saccular macula, from the inferior vestibular nerve, the vestibular nuclei, the vestibule-spinal tract and effectors muscles. Objective: Perform a systematic review of the pertinent literature by means of database (COCHRANE, MEDLINE, LILACS, CAPES. Conclusion: The clinical application of the VEMP has expanded in the last years, as goal that this exam is used as complementary in the otoneurological evaluation currently used. But, methodological issues must be clarified. This way, this method when combined with the standard protocol, can provide a more widely evaluation from the vestibular system. The standardization of the methodology is fundamental criterion for the replicability and sensibility of the exam.

  7. Music evokes vivid autobiographical memories.

    Science.gov (United States)

    Belfi, Amy M; Karlan, Brett; Tranel, Daniel

    2016-08-01

    Music is strongly intertwined with memories-for example, hearing a song from the past can transport you back in time, triggering the sights, sounds, and feelings of a specific event. This association between music and vivid autobiographical memory is intuitively apparent, but the idea that music is intimately tied with memories, seemingly more so than other potent memory cues (e.g., familiar faces), has not been empirically tested. Here, we compared memories evoked by music to those evoked by famous faces, predicting that music-evoked autobiographical memories (MEAMs) would be more vivid. Participants listened to 30 songs, viewed 30 faces, and reported on memories that were evoked. Memories were transcribed and coded for vividness as in Levine, B., Svoboda, E., Hay, J. F., Winocur, G., & Moscovitch, M. [2002. Aging and autobiographical memory: Dissociating episodic from semantic retrieval. Psychology and Aging, 17, 677-689]. In support of our hypothesis, MEAMs were more vivid than autobiographical memories evoked by faces. MEAMs contained a greater proportion of internal details and a greater number of perceptual details, while face-evoked memories contained a greater number of external details. Additionally, we identified sex differences in memory vividness: for both stimulus categories, women retrieved more vivid memories than men. The results show that music not only effectively evokes autobiographical memories, but that these memories are more vivid than those evoked by famous faces.

  8. Adjective metaphors evoke negative meanings.

    Science.gov (United States)

    Sakamoto, Maki; Utsumi, Akira

    2014-01-01

    Previous metaphor studies have paid much attention to nominal metaphors and predicative metaphors, but little attention has been given to adjective metaphors. Although some studies have focused on adjective metaphors, they only examined differences in the acceptability of various types of adjective metaphors. This paper explores the cognitive effects evoked by adjective metaphors. Three psychological experiments revealed that (1) adjective metaphors, especially those modified by color adjectives, tend to evoke negative effect; (2) although the meanings of metaphors are basically affected by the meanings of their vehicles, when a vehicle has a neutral meaning, negative meanings are evoked most frequently for adjective metaphors compared to nominal and predicative metaphors; (3) negative meanings evoked by adjective metaphors are related to poeticness, and poetic metaphors evoke negative meanings more easily than less poetic metaphors. Our research sheds new light on studies of the use of metaphor, which is one of the most basic human cognitive abilities.

  9. Adjective metaphors evoke negative meanings.

    Directory of Open Access Journals (Sweden)

    Maki Sakamoto

    Full Text Available Previous metaphor studies have paid much attention to nominal metaphors and predicative metaphors, but little attention has been given to adjective metaphors. Although some studies have focused on adjective metaphors, they only examined differences in the acceptability of various types of adjective metaphors. This paper explores the cognitive effects evoked by adjective metaphors. Three psychological experiments revealed that (1 adjective metaphors, especially those modified by color adjectives, tend to evoke negative effect; (2 although the meanings of metaphors are basically affected by the meanings of their vehicles, when a vehicle has a neutral meaning, negative meanings are evoked most frequently for adjective metaphors compared to nominal and predicative metaphors; (3 negative meanings evoked by adjective metaphors are related to poeticness, and poetic metaphors evoke negative meanings more easily than less poetic metaphors. Our research sheds new light on studies of the use of metaphor, which is one of the most basic human cognitive abilities.

  10. Autoregressive smoothing of GOMOS transmittances

    Science.gov (United States)

    Fussen, D.; Vanhellemont, F.; Bingen, C.; Kyrölä, B.; Tamminen, J.; Sofieva, V.; Hassinen, S.; Seppälä, A.; Verronen, P. T.; Bertaux, J. L.; Hauchecorne, A.; Dalaudier, F.; d'Andon, O. Fanton; Barrot, G.; Mangin, A.; Theodore, B.; Guirlet, M.; Renard, J. B.; Fraisse, R.; Snoeij, P.; Koopman, R.; Saavedra, L.

    GOMOS is a stellar occultation instrument onboard ENVISAT. It has already measured several hundreds of thousands occultations since March 2002. In some circumstances, the obliqueness of the star setting causes the remote sounding of possible horizontal turbulence that cannot be adequately corrected by using the fast photometer signals, leading to the presence of residual scintillation in the atmospheric transmittance. We investigate the mechanism that produces this spurious signal that may cause the retrieval of wavy constituent profiles. A special algorithm of vertical autoregressive smoothing (VAS) is proposed that takes into account the physical correlation between adjacent measurements at different tangent altitudes. A regularization parameter of the method may be optimized on basis of the minimal correlation between the residuals as prescribed by the Durbin-Watson statistics. The improvements obtained in the retrieval of both O 3 and NO 2 number density profiles is presented and discussed with respect to the results of the official data processing model.

  11. 47 CFR 15.212 - Modular transmitters.

    Science.gov (United States)

    2010-10-01

    ... radiofrequency transmitter device that is typically incorporated into another product, host or device. Split... transmitter control element (or specific hardware on which the software that controls the radio operation... powered, it must comply with the AC line conducted requirements found in § 15.207. AC or DC power lines...

  12. 77 FR 1779 - Emergency Locator Transmitters (ELTs)

    Science.gov (United States)

    2012-01-11

    ... Locator Transmitter (ELT) Equipment. SUMMARY: This notice announces the FAA's intent to cancel TSO-C91a, Emergency Locator Transmitter (ELT) Equipment. The effect of the cancelled TSO will result in no new TSO... the 14 Code of ] Federal Regulation (14 CFR) Sec. 91.207 ELT equipage requirement. DATES: Comments...

  13. 47 CFR 80.911 - VHF transmitter.

    Science.gov (United States)

    2010-10-01

    ... MARITIME SERVICES Compulsory Radiotelephone Installations for Small Passenger Boats § 80.911 VHF..., measured at the power input terminals to the transmitter, and the output power of the transmitter, terminated in a matching artificial load, must be measured at the end of 10 minutes of continuous operation...

  14. Biophysical and Biochemical Mechanisms in Synaptic Transmitter Release.

    Science.gov (United States)

    1992-01-31

    B. "Temperature induced spawning in Echi- In addition to the reports contained in this issue, the narachnius parma experiments? Knot when they’re...T. Brady, D. van der Kooy, and J. A. Connolly De Camilli. P.. S. M. Hams , Jr.. W. B. Huttner, and P. Greengard (1987) A unique tubulin antibody which

  15. Modeling NDT piezoelectric ultrasonic transmitters.

    Science.gov (United States)

    San Emeterio, J L; Ramos, A; Sanz, P T; Ruíz, A; Azbaid, A

    2004-04-01

    Ultrasonic NDT applications are frequently based on the spike excitation of piezoelectric transducers by means of efficient pulsers which usually include a power switching device (e.g. SCR or MOS-FET) and some rectifier components. In this paper we present an approximate frequency domain electro-acoustic model for pulsed piezoelectric ultrasonic transmitters which, by integrating partial models of the different stages (driving electronics, tuning/matching networks and broadband piezoelectric transducer), allows the computation of the emission transfer function and output force temporal waveform. An approximate frequency domain model is used for the evaluation of the electrical driving pulse from the spike generator. Tuning circuits, interconnecting cable and mechanical impedance matching layers are modeled by means of transmission lines and the classical quadripole approach. The KLM model is used for the piezoelectric transducer. In addition, a PSPICE scheme is used for an alternative simulation of the broadband driving spike, including the accurate evaluation of non-linear driving effects. Several examples illustrate the capabilities of the specifically developed software.

  16. Ciguatoxins Evoke Potent CGRP Release by Activation of Voltage-Gated Sodium Channel Subtypes NaV1.9, NaV1.7 and NaV1.1

    Directory of Open Access Journals (Sweden)

    Filip Touska

    2017-08-01

    Full Text Available Ciguatoxins (CTXs are marine toxins that cause ciguatera fish poisoning, a debilitating disease dominated by sensory and neurological disturbances that include cold allodynia and various painful symptoms as well as long-lasting pruritus. Although CTXs are known as the most potent mammalian sodium channel activator toxins, the etiology of many of its neurosensory symptoms remains unresolved. We recently described that local application of 1 nM Pacific Ciguatoxin-1 (P-CTX-1 into the skin of human subjects induces a long-lasting, painful axon reflex flare and that CTXs are particularly effective in releasing calcitonin-gene related peptide (CGRP from nerve terminals. In this study, we used mouse and rat skin preparations and enzyme-linked immunosorbent assays (ELISA to study the molecular mechanism by which P-CTX-1 induces CGRP release. We show that P-CTX-1 induces CGRP release more effectively in mouse as compared to rat skin, exhibiting EC50 concentrations in the low nanomolar range. P-CTX-1-induced CGRP release from skin is dependent on extracellular calcium and sodium, but independent from the activation of various thermosensory transient receptor potential (TRP ion channels. In contrast, lidocaine and tetrodotoxin (TTX reduce CGRP release by 53–75%, with the remaining fraction involving L-type and T-type voltage-gated calcium channels (VGCC. Using transgenic mice, we revealed that the TTX-resistant voltage-gated sodium channel (VGSC NaV1.9, but not NaV1.8 or NaV1.7 alone and the combined activation of the TTX-sensitive VGSC subtypes NaV1.7 and NaV1.1 carry the largest part of the P-CTX-1-caused CGRP release of 42% and 34%, respectively. Given the contribution of CGRP to nociceptive and itch sensing pathways, our findings contribute to a better understanding of sensory symptoms of acute and chronic ciguatera that may help in the identification of potential therapeutics.

  17. Ciguatoxins Evoke Potent CGRP Release by Activation of Voltage-Gated Sodium Channel Subtypes NaV1.9, NaV1.7 and NaV1.1.

    Science.gov (United States)

    Touska, Filip; Sattler, Simon; Malsch, Philipp; Lewis, Richard J; Reeh, Peter W; Zimmermann, Katharina

    2017-08-30

    Ciguatoxins (CTXs) are marine toxins that cause ciguatera fish poisoning, a debilitating disease dominated by sensory and neurological disturbances that include cold allodynia and various painful symptoms as well as long-lasting pruritus. Although CTXs are known as the most potent mammalian sodium channel activator toxins, the etiology of many of its neurosensory symptoms remains unresolved. We recently described that local application of 1 nM Pacific Ciguatoxin-1 (P-CTX-1) into the skin of human subjects induces a long-lasting, painful axon reflex flare and that CTXs are particularly effective in releasing calcitonin-gene related peptide (CGRP) from nerve terminals. In this study, we used mouse and rat skin preparations and enzyme-linked immunosorbent assays (ELISA) to study the molecular mechanism by which P-CTX-1 induces CGRP release. We show that P-CTX-1 induces CGRP release more effectively in mouse as compared to rat skin, exhibiting EC50 concentrations in the low nanomolar range. P-CTX-1-induced CGRP release from skin is dependent on extracellular calcium and sodium, but independent from the activation of various thermosensory transient receptor potential (TRP) ion channels. In contrast, lidocaine and tetrodotoxin (TTX) reduce CGRP release by 53-75%, with the remaining fraction involving L-type and T-type voltage-gated calcium channels (VGCC). Using transgenic mice, we revealed that the TTX-resistant voltage-gated sodium channel (VGSC) NaV1.9, but not NaV1.8 or NaV1.7 alone and the combined activation of the TTX-sensitive VGSC subtypes NaV1.7 and NaV1.1 carry the largest part of the P-CTX-1-caused CGRP release of 42% and 34%, respectively. Given the contribution of CGRP to nociceptive and itch sensing pathways, our findings contribute to a better understanding of sensory symptoms of acute and chronic ciguatera that may help in the identification of potential therapeutics.

  18. Evoked emotions predict food choice.

    Directory of Open Access Journals (Sweden)

    Jelle R Dalenberg

    Full Text Available In the current study we show that non-verbal food-evoked emotion scores significantly improve food choice prediction over merely liking scores. Previous research has shown that liking measures correlate with choice. However, liking is no strong predictor for food choice in real life environments. Therefore, the focus within recent studies shifted towards using emotion-profiling methods that successfully can discriminate between products that are equally liked. However, it is unclear how well scores from emotion-profiling methods predict actual food choice and/or consumption. To test this, we proposed to decompose emotion scores into valence and arousal scores using Principal Component Analysis (PCA and apply Multinomial Logit Models (MLM to estimate food choice using liking, valence, and arousal as possible predictors. For this analysis, we used an existing data set comprised of liking and food-evoked emotions scores from 123 participants, who rated 7 unlabeled breakfast drinks. Liking scores were measured using a 100-mm visual analogue scale, while food-evoked emotions were measured using 2 existing emotion-profiling methods: a verbal and a non-verbal method (EsSense Profile and PrEmo, respectively. After 7 days, participants were asked to choose 1 breakfast drink from the experiment to consume during breakfast in a simulated restaurant environment. Cross validation showed that we were able to correctly predict individualized food choice (1 out of 7 products for over 50% of the participants. This number increased to nearly 80% when looking at the top 2 candidates. Model comparisons showed that evoked emotions better predict food choice than perceived liking alone. However, the strongest predictive strength was achieved by the combination of evoked emotions and liking. Furthermore we showed that non-verbal food-evoked emotion scores more accurately predict food choice than verbal food-evoked emotions scores.

  19. Evoked emotions predict food choice.

    Science.gov (United States)

    Dalenberg, Jelle R; Gutjar, Swetlana; Ter Horst, Gert J; de Graaf, Kees; Renken, Remco J; Jager, Gerry

    2014-01-01

    In the current study we show that non-verbal food-evoked emotion scores significantly improve food choice prediction over merely liking scores. Previous research has shown that liking measures correlate with choice. However, liking is no strong predictor for food choice in real life environments. Therefore, the focus within recent studies shifted towards using emotion-profiling methods that successfully can discriminate between products that are equally liked. However, it is unclear how well scores from emotion-profiling methods predict actual food choice and/or consumption. To test this, we proposed to decompose emotion scores into valence and arousal scores using Principal Component Analysis (PCA) and apply Multinomial Logit Models (MLM) to estimate food choice using liking, valence, and arousal as possible predictors. For this analysis, we used an existing data set comprised of liking and food-evoked emotions scores from 123 participants, who rated 7 unlabeled breakfast drinks. Liking scores were measured using a 100-mm visual analogue scale, while food-evoked emotions were measured using 2 existing emotion-profiling methods: a verbal and a non-verbal method (EsSense Profile and PrEmo, respectively). After 7 days, participants were asked to choose 1 breakfast drink from the experiment to consume during breakfast in a simulated restaurant environment. Cross validation showed that we were able to correctly predict individualized food choice (1 out of 7 products) for over 50% of the participants. This number increased to nearly 80% when looking at the top 2 candidates. Model comparisons showed that evoked emotions better predict food choice than perceived liking alone. However, the strongest predictive strength was achieved by the combination of evoked emotions and liking. Furthermore we showed that non-verbal food-evoked emotion scores more accurately predict food choice than verbal food-evoked emotions scores.

  20. A VLF transmitter on the Space Shuttle

    Science.gov (United States)

    Inan, U. S.; Bell, T. F.; Helliwell, R. A.; Katsufrakis, K. P.

    The use of space-borne transmitters for the study of interactions of energetic radiation belt particles and coherent plasma waves in the earth's magnetosphere has been considered. The proposed Space Shuttle/Space Lab system would provide a useful VLF transmitter platform since it can lift the required large payloads into orbit, erect long antennas, supply the electrical power required, and provide real-time control. A study is conducted of the power budget of such a VLF transmitter in an attempt to assess the feasibility of the experiment. It is found that a 1-10 kW transmitter placed on the Space Shuttle/Space Lab system can inject from one watt to up to a few kilowatts of wave power into the whistler mode. Recent results of ground-based VLF wave-injection experiments show that such power levels would be more than enough for initiating nonlinear wave growth and amplification and emission triggering in the magnetosphere.

  1. World War II Weather Record Transmittances

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — World War II Weather Record Transmittances are a record of the weather and meteorological data observed during World War II and transferred to the archive. It...

  2. Quantum Communications Transmitter at 775 nm Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose a novel new architecture for a quantum communications laser transmitter that is designed for free-space polarization encoded quantum key distribution...

  3. Comparing the survival rate of juvenile Chinook salmon migrating through hydropower systems using injectable and surgical acoustic transmitters

    Science.gov (United States)

    Deng, Z. D.; Martinez, J. J.; Li, H.; Harnish, R. A.; Woodley, C. M.; Hughes, J. A.; Li, X.; Fu, T.; Lu, J.; McMichael, G. A.; Weiland, M. A.; Eppard, M. B.; Skalski, J. R.; Townsend, R. L.

    2017-02-01

    Acoustic telemetry is one of the primary technologies for studying the behavior and survival of fishes throughout the world. The size and performance of the transmitter are key limiting factors. The newly developed injectable transmitter is the first acoustic transmitter that can be implanted via injection instead of surgery. A two-part field study was conducted to evaluate the performance of the injectable transmitter and its effect on the survival of implanted fish. The injectable transmitter performed well and similarly to the proceeding generation of commercially-available JSATS transmitters tested concurrently. Snake River subyearling Chinook salmon smolts implanted with the injectable transmitter had a higher survival probability from release to each of eleven downstream detection arrays, because reach-specific survival estimates were significantly higher for the injectable group in three of the eleven reaches examined. Overall, the injectable group had a 0.263 (SE = 0.017) survival probability over the entire 500 km study area compared to 0.199 (0.012) for the surgically implanted group. The reduction in size and ability to implant the new transmitter via injection has reduced the tag or tagging effect bias associated with studying small fishes. The information gathered with this new technology is helping to evaluate the impacts of dams on fishes.

  4. Cyclic AMP directs inositol (1,4,5)-trisphosphate-evoked Ca2+ signalling to different intracellular Ca2+ stores

    OpenAIRE

    Tovey, Stephen C.; Taylor, Colin W.

    2013-01-01

    Cholesterol depletion reversibly abolishes carbachol-evoked Ca2+ release from inositol (1,4,5)-trisphosphate (IP3)-sensitive stores, without affecting the distribution of IP3 receptors (IP3R) or endoplasmic reticulum, IP3 formation or responses to photolysis of caged IP3. Receptors that stimulate cAMP formation do not alone evoke Ca2+ signals, but they potentiate those evoked by carbachol. We show that these potentiated signals are entirely unaffected by cholesterol depletion and that, within...

  5. Evoked Emotions Predict Food Choice

    NARCIS (Netherlands)

    Dalenberg, Jelle R.; Gutjar, Swetlana; ter Horst, Gert J.; de Graaf, Kees; Renken, Remco J.; Jager, Gerry

    2014-01-01

    In the current study we show that non-verbal food-evoked emotion scores significantly improve food choice prediction over merely liking scores. Previous research has shown that liking measures correlate with choice. However, liking is no strong predictor for food choice in real life environments.

  6. Quantitative Chemical Measurements of Vesicular Transmitters with Electrochemical Cytometry.

    Science.gov (United States)

    Li, Xianchan; Dunevall, Johan; Ewing, Andrew G

    2016-10-18

    Electrochemical cytometry adds a new dimension to our ability to study the chemistry and chemical storage of transmitter molecules stored in nanometer vesicles. The approach involves the adsorption and subsequent rupture of vesicles on an electrode surface during which the electroactive contents are quantitatively oxidized (or reduced). The measured current allows us to count the number of molecules in the vesicles using Faraday's law and to correlate this to the amount of molecules released when single exocytosis events take place at communicating cells. The original format for this method involved a capillary electrophoresis separation step to singly address each vesicle, but we have more recently discovered that cellular vesicles tend to adsorb to carbon electrodes and spontaneously as well as stochastically rupture to give mostly single vesicle events. This approach, called impact electrochemical cytometry, even though the impact is perhaps not the important part of this process, has been studied and the vesicle rupture appears to be at the interface between the vesicle and the electrode and is probably driven by electroporation. The pore size and rate of content electrolysis are a function of the pore diameter and the presence of a protein core in the vesicles. In model liposomes with no protein, events appear extremely rapidly as the soft nanoparticles impact the electrode and the contents are oxidized. It appears that the proteins decorating the surface of the vesicle are important in maintaining a gap from the electrode and when this gap is closed electroporation takes place. Models of the event response times suggest the pores formed are small enough so we can carry out these measurements at nanotip electrodes and we have used this to quantify the vesicle content in living cells in a mode we call intracellular impact electrochemical cytometry. The development of electrochemical cytometry allows comparison between vesicle content and vesicular release and

  7. Ryanodine-, IP3- and NAADP-dependent calcium stores control acetylcholine release.

    Science.gov (United States)

    Chameau, P; Van de Vrede, Y; Fossier, P; Baux, G

    2001-11-01

    Injections of inositol trisphosphate (IP3) or nicotinamide adenine dinucleotide phosphate (NAADP) into the presynaptic neurone of an identified cholinergic synapse in the buccal ganglion of Aplysia californica increased the amplitude of the inhibitory postsynaptic current evoked by a presynaptic action potential. This suggests that Ca2+ release from various Ca2+ stores can modulate acetylcholine (ACh) release. Specific blockade of the calcium-induced calcium release (CICR) mechanism with ryanodine, or of IP3-induced calcium release with heparin, abolished the effects of IP3, but not the effects of NAADP, suggesting the presence of an intracellular Ca2+ pool independent of those containing ryanodine receptors (RyR) or IP3 receptors. To reinforce electrophysiological observations, intracellular [Ca2+]i changes were measured using the fluorescent dye rhod-2. Injections of cyclic ADP-ribose (an activator of RyR), IP3 or NAADP into the presynaptic neurone induced transient increases in the free intracellular Ca2+ concentration. RyR- and IP3-induced increases were prevented by application of respective selective antagonists but not NAADP-induced increases. Our results show that RyR-dependent, IP3-dependent, and NAADP-dependent Ca2+ stores are present in the same presynaptic terminal but are differently involved in the regulation of the presynaptic Ca2+ concentration that triggers transmitter release.

  8. Evoked Emotions Predict Food Choice

    OpenAIRE

    Dalenberg, Jelle R.; Swetlana Gutjar; Gert J Ter Horst; Kees de Graaf; Renken, Remco J.; Gerry Jager

    2014-01-01

    In the current study we show that non-verbal food-evoked emotion scores significantly improve food choice prediction over merely liking scores. Previous research has shown that liking measures correlate with choice. However, liking is no strong predictor for food choice in real life environments. Therefore, the focus within recent studies shifted towards using emotion-profiling methods that successfully can discriminate between products that are equally liked. However, it is unclear how well ...

  9. EVOKED CAVERNOUS ACTIVITY: NEUROANATOMIC IMPLICATIONS

    OpenAIRE

    Yilmaz, Ugur; Vicars, Brenda; Yang, Claire C.

    2009-01-01

    We investigated the autonomic innervation of the penis by using evoked cavernous activity (ECA). We recruited 7 males with thoracic spinal cord injury (SCI) and sexual dysfunction and 6 males who were scheduled to have pelvic surgery (PS), specifically non-nerve-sparing radical cystoprostatectomy. In the PS subjects, ECA was performed both pre- and postoperatively. The left median nerve was electrically stimulated and ECA was recorded with two concentric electromyography needles placed into t...

  10. Model of evoked rabbit phonation.

    Science.gov (United States)

    Ge, Ping Jiang; French, Lesley C; Ohno, Tsunehisa; Zealear, David L; Rousseau, Bernard

    2009-01-01

    We describe a method for eliciting phonation in an in vivo rabbit preparation using low-frequency, bipolar pulsed stimulation of the cricothyroid muscles with airflow delivered to the glottis. Ten New Zealand White breeder rabbits weighing 3 to 5 kg were used in this study. The cricothyroid muscles were isolated bilaterally, and separate pairs of anode-cathode hooked-wire electrodes were inserted into each muscle. A Grass S-88 stimulator and 2 constant-current PSIU6 isolation units were used to deliver bipolar square wave pulses to each cricothyroid muscle, with airflow delivered to the glottis through a cuffed endotracheal tube. Phonation was evoked with a 50-Hz, 4-mA stimulus train of 1-ms pulses delivered to each cricothyroid muscle. The pulse trains were on for 2 seconds and were repeated every 5 seconds over a period of 180 minutes. Airflow was delivered at 143 cm3/s, producing phonation measuring 71 to 85 dB sound pressure level. Evoked phonation is feasible in rabbits by use of bipolar stimulation of the cricothyroid muscles with airflow delivered to the glottis. The in vivo rabbit preparation described may provide a useful small animal option for studies of evoked phonation. From the level and consistency of the adduction observed, we hypothesize that current spreading to the underlying adductor muscles and nerves resulted in neural pathway involvement beyond discrete activation of the cricothyroid muscle, providing sufficient approximation of the vocal folds for phonation.

  11. Mortality, Transmitter Retention, Growth, and Wound Healing in Juvenile Salmon Injected with Micro Acoustic Transmitters

    Energy Technology Data Exchange (ETDEWEB)

    Liss, Stephanie A.; Brown, Richard S.; Deters, Katherine A.; Walker, Ricardo W.; Deng, Z. Daniel; Eppard, M. Brad; Townsend, Richard L.; Seaburg, Adam G.

    2016-07-28

    A cylindrical acoustic transmitter (AT; 0.2 g) has been developed for injection into the peritoneum of fish. Laboratory studies can provide tagging guidelines to minimize the effect of implantation techniques and transmitter burden (relative weight of the transmitter to the weight of the fish) in fish before a transmitter is used in field studies. The goal of this study was to examine response variables (mortality, transmitter expulsion, growth, wound area) of juvenile Chinook Salmon (Oncorhynchus tschawytscha; 65–104 mm fork length [FL]) injected with an AT along a wide range of sizes that could lead to a guideline for minimizing tagging effects. The overarching goal was to determine a minimum size threshold for fish that can be injected, while minimizing adverse transmitter effects. Juveniles (n = 700) were separated into four treatments: (1) acoustic transmitter injection (AT), (2) AT and a passive integrated transponder tag injection (AT+PIT), (3) visual implant elastomer injection (Marked control), and (4) unmarked (Unmarked control). Fish were evaluated weekly for four weeks, and again at the end of the study (60 d post-tagging). Fish injected with an AT or an AT+PIT experienced greater mortality than Marked controls. By 60 d post-tagging, transmitter expulsion was 44% for AT fish and 20% for AT+PIT fish. Fish injected with an AT or an AT+PIT grew (FL and weight gain) significantly less than Marked controls, and no minimum size thresholds were detected. Finally, initial size (FL) significantly affected wound area in AT and AT+PIT fish. A size threshold was only identified on Day 7 (85.1 mm) for AT+PIT fish, indicating that wound areas in fish < 85.1 mm were larger than wound areas of fish > 85.1 mm. This research suggests that injecting juveniles with an AT or an AT+PIT had a greater effect on smaller fish than larger fish.

  12. Purines released from astrocytes inhibit excitatory synaptic transmission in the ventral horn of the spinal cord

    Directory of Open Access Journals (Sweden)

    Eva Meier Carlsen

    2014-06-01

    Full Text Available Spinal neuronal networks are essential for motor function. They are involved in the integration of sensory inputs and the generation of rhythmic motor outputs. They continuously adapt their activity to the internal state of the organism and to the environment. This plasticity can be provided by different neuromodulators. These substances are usually thought of being released by dedicated neurons. However, in other networks from the central nervous system synaptic transmission is also modulated by transmitters released from astrocytes. The star-shaped glial cell responds to neurotransmitters by releasing gliotransmitters, which in turn modulate synaptic transmission. Here we investigated if astrocytes present in the ventral horn of the spinal cord modulate synaptic transmission. We evoked synaptic inputs in ventral horn neurons recorded in a slice preparation from the spinal cord of neonatal mice. Neurons responded to electrical stimulation by monosynaptic EPSCs. We used mice expressing the enhanced green fluorescent protein under the promoter of the glial fibrillary acidic protein to identify astrocytes. Chelating calcium with BAPTA in a single neighboring astrocyte increased the amplitude of synaptic currents. In contrast, when we selectively stimulated astrocytes by activating PAR-1 receptors with the peptide TFLLR, the amplitude of EPSCs evoked by a paired stimulation protocol was reduced. The paired-pulse ratio was increased, suggesting an inhibition occurring at the presynaptic side of synapses. In the presence of blockers for extracellular ectonucleotidases, TFLLR did not induce presynaptic inhibition. Puffing adenosine reproduced the effect of TFLLR and blocking adenosine A1 receptors with DPCPX prevented it. Altogether our results show that ventral horn astrocytes are responsible for a tonic and a phasic inhibition of excitatory synaptic transmission by releasing ATP, which gets converted into adenosine that binds to inhibitory

  13. Complexin Mutants Reveal Partial Segregation between Recycling Pathways That Drive Evoked and Spontaneous Neurotransmission

    Science.gov (United States)

    Sabeva, Nadezhda; Cho, Richard W.; Vasin, Alexander; Gonzalez, Agustin; Littleton, J. Troy

    2017-01-01

    Synaptic vesicles fuse at morphological specializations in the presynaptic terminal termed active zones (AZs). Vesicle fusion can occur spontaneously or in response to an action potential. Following fusion, vesicles are retrieved and recycled within nerve terminals. It is still unclear whether vesicles that fuse spontaneously or following evoked release share similar recycling mechanisms. Genetic deletion of the SNARE-binding protein complexin dramatically increases spontaneous fusion, with the protein serving as the synaptic vesicle fusion clamp at Drosophila synapses. We examined synaptic vesicle recycling pathways at complexin null neuromuscular junctions, where spontaneous release is dramatically enhanced. We combined loading of the lipophilic dye FM1–43 with photoconversion, electron microscopy, and electrophysiology to monitor evoked and spontaneous recycling vesicle pools. We found that the total number of recycling vesicles was equal to those retrieved through spontaneous and evoked pools, suggesting that retrieval following fusion is partially segregated for spontaneous and evoked release. In addition, the kinetics of FM1–43 destaining and synaptic depression measured in the presence of the vesicle-refilling blocker bafilomycin indicated that spontaneous and evoked recycling pools partially intermix during the release process. Finally, FM1–43 photoconversion combined with electron microscopy analysis indicated that spontaneous recycling preferentially involves synaptic vesicles in the vicinity of AZs, whereas vesicles recycled following evoked release involve a larger intraterminal pool. Together, these results suggest that spontaneous and evoked vesicles use separable recycling pathways and then partially intermix during subsequent rounds of fusion. SIGNIFICANCE STATEMENT Neurotransmitter release involves fusion of synaptic vesicles with the plasma membrane in response to an action potential, or spontaneously in the absence of stimulation. Upon

  14. Agricultural applications of NIR reflectance and transmittance

    DEFF Research Database (Denmark)

    Gislum, René

    2009-01-01

    There has been a considerable increase in the use of near infrared (NIR) reflectance and transmittance spectroscopy technologies for rapid determination of quality parameters in agriculture, including applications within crop product quality, feed and food quality, manure quality, soil analyses etc....... As a result it was decided to arrange a seminar within the Nordic Association of Agricultural Scientists. This is a report of the meeting....

  15. 3H-D-aspartate release from cerebellar granule neurons is differentially regulated by glutamate- and K(+)-stimulation

    DEFF Research Database (Denmark)

    Belhage, B; Rehder, V; Hansen, Gert Helge

    1992-01-01

    transmitter release was dependent on an intact cytoskeleton or not, the colchicine-like drug Nocodazole, which also blocks transport of vesicles, was used. K(+)-stimulated transmitter release consisted for the major part (around 70%) of a Ca(2+)-dependent, Nocodazole sensitive release component and this K...

  16. Achieving Presence through Evoked Reality

    Science.gov (United States)

    Pillai, Jayesh S.; Schmidt, Colin; Richir, Simon

    2013-01-01

    The sense of “Presence” (evolving from “telepresence”) has always been associated with virtual reality research and is still an exceptionally mystifying constituent. Now the study of presence clearly spans over various disciplines associated with cognition. This paper attempts to put forth a concept that argues that it’s an experience of an “Evoked Reality (ER)” (illusion of reality) that triggers an “Evoked Presence (EP)” (sense of presence) in our minds. A Three Pole Reality Model is proposed to explain this phenomenon. The poles range from Dream Reality to Simulated Reality with Primary (Physical) Reality at the center. To demonstrate the relationship between ER and EP, a Reality-Presence Map is developed. We believe that this concept of ER and the proposed model may have significant applications in the study of presence, and in exploring the possibilities of not just virtual reality but also what we call “reality.” PMID:23550234

  17. Evoked Electromyographically Controlled Electrical Stimulation

    Directory of Open Access Journals (Sweden)

    Mitsuhiro Hayashibe

    2016-07-01

    Full Text Available Time-variant muscle responses under electrical stimulation (ES are often problematic for all the applications of neuroprosthetic muscle control. This situation limits the range of ES usage in relevant areas, mainly due to muscle fatigue and also to changes in stimulation electrode contact conditions, especially in transcutaneous ES. Surface electrodes are still the most widely used in noninvasive applications.Electrical field variations caused by changes in the stimulation contact condition markedly affect the resulting total muscle activation levels. Fatigue phenomena under functional electrical stimulation (FES are also well known source of time-varying characteristics coming from muscle response under ES. Therefore it is essential to monitor the actual muscle state and assess the expected muscle response by ES so as to improve the current ES system in favour of adaptive muscle-response-aware FES control. To deal with this issue, we have been studying a novel control technique using evoked electromyography (eEMG signals to compensate for these muscle time-variances under ES for stable neuroprosthetic muscle control. In this perspective article, I overview the background of this topic and highlight important points to be aware of when using ES to induce the desired muscle activation regardless of the time-variance. I also demonstrate how to deal with the common critical problem of ES to move toward robust neuroprosthetic muscle control with the Evoked Electromyographically Controlled Electrical Stimulation paradigm.

  18. In vivo microdialysis studies on the effects of decortication and excitotoxic lesions on kainic acid-induced calcium fluxes, and endogenous amino acid release, in the rat striatum

    Energy Technology Data Exchange (ETDEWEB)

    Butcher, S.P.; Lazarewicz, J.W.; Hamberger, A.

    1987-11-01

    The in vivo effects of kainate (1 mM) on fluxes of /sup 45/Ca2+, and endogenous amino acids, were examined in the rat striatum using the brain microdialysis technique. Kainate evoked a rapid decrease in dialysate /sup 45/Ca2+, and an increase in the concentration of amino acids in dialysates in Ca2+-free dialysates. Taurine was elevated six- to 10-fold, glutamate two- to threefold, and aspartate 1.5- to twofold. There was also a delayed increase in phosphoethanolamine, whereas nonneuroactive amino acids were increased only slightly. The kainic acid-evoked reduction in dialysate /sup 45/Ca2+ activity was attenuated in striata lesioned previously with kainate, suggesting the involvement of intrinsic striatal neurons in this response. The increase in taurine concentration induced by kainate was slightly smaller under these conditions. Decortication did not affect the kainate-evoked alterations in either dialysate /sup 45/Ca2+ or amino acids. These data suggest that kainate does not release acidic amino acids from their transmitter pools located in corticostriatal terminals.

  19. Neurotrophin-evoked depolarization requires the sodium channel Na(V)1.9.

    Science.gov (United States)

    Blum, Robert; Kafitz, Karl W; Konnerth, Arthur

    2002-10-17

    Brain-derived neurotrophic factor (BDNF) and other neurotrophins are essential for normal brain function. Many types of neurons in the central nervous system are excited by BDNF or neurotrophin-4/5, an action that has recently been implicated in synaptic plasticity. The mechanisms involved in this transmitter-like action of neurotrophins remains unclear. Here, by screening candidate genes with an antisense messenger RNA expression approach and by co-expressing the receptor tyrosine kinase TrkB and various sodium channels, we demonstrate that the tetrodotoxin-insensitive sodium channel Na(V)1.9 underlies the neurotrophin-evoked excitation. These results establish the molecular basis of neurotrophin-evoked depolarization and reveal a mechanism of ligand-mediated sodium channel activation.

  20. Surgical implantation of transmitters into fish

    Science.gov (United States)

    Mulcahy, Daniel M.

    2003-01-01

    Although the Animal Welfare Act does not cover poikilotherms, individual institutions and policies and legal requirements other than the Animal Welfare Act (e.g., the US Public Health Service and the Interagency Research Animal Committee's Principles for the Utilization and Care of Vertebrate Animals Used in Testing, Research, and Training) require the review of projects involving fish by institutional animal care and use committees (IACUCs). IACUCs may, however, lack the knowledge and experience to evaluate fish projects judiciously, especially when the projects are in field settings. Surgeries involving implantation of transmitters and other instruments into the coelom, which now comprise a very common research tool in the study of free-ranging fishes, are examples of surgeries that use a broad spectrum of surgical and anesthetic techniques, some of which would not be considered acceptable for similar work on mammals. IACUCs should apply the standards they would expect to be used for surgeries on homeotherms to surgeries on fish. Surgeons should be carefully trained and experienced. Surgical instruments and transmitters should be sterile. Regulations and laws on the use of drugs in animals should be followed, particularly those concerned with anesthetics and antibiotics used on free-ranging fish. Exceptions to surgical procedures should be made only when circumstances are extreme enough to warrant the use of less than optimal procedures.

  1. Behavior of sandhill cranes harnessed with different satellite transmitters

    Science.gov (United States)

    Olsen, Glenn H.; Ellis, D.H.; Landfried, S.E.; Miller, L.H.; Klugman, S.S.; Fuller, M.R.; Vermillion, C.H.

    1992-01-01

    The effectiveness of various attachment methods and designs of platform transmitting terminals (PTT's) was tested on captive sandhill cranes (Grus canadensis) at the Patuxent Wildlife Research Center, Laurel, Maryland, during 1989-91. Combinations of attachment and transmitter designs included neoprene cord harness with batteries separate from the transmitter (2 harness designs), Teflon ribbon harness with batteries incorporated into the transmitter package (4 transmitter models), and a package attached directly to the bird with epoxy glue only. Physical effects seen on cranes wearing PTT's ranged from skin lacerations (caused by rubbing of harness material) to no observed effects (other than feather wear). The most successful harness material and design utilized a Teflon ribbon harness with the 4 ribbon ends from the transmitter forming a neck loop and a body loop joined at the sternum. Time spent by sandhill cranes performing most activities did not change after transmitter attachment using this harness method.

  2. Automobile windscreen rake, spectacle lenses, and effective transmittance.

    Science.gov (United States)

    Walsh, Glyn

    2009-12-01

    To investigate the effect of windscreen rake angle on effective transmittance and the contribution of spectacle lenses to the total transmittance of the system. Theoretical analysis has been carried out using the Fresnel reflectance equations. Windscreen rake can reduce effective transmittance significantly at angles present on modern aerodynamic vehicles. Spectacle lenses reduce the total transmittance still further, often to below the minimum level permissible in current international standards for windscreens. Drivers should always be supplied antireflection-coated lenses where there is a chance of their spectacles being used for night-time driving, if current International standards for windscreen transmittance are to be met by the spectacle-windscreen combination. Windscreen rake angle should be accounted for both in the International Organization for Standardization transmittance standards and in roadside testing devices.

  3. An Energy Harvesting Underwater Acoustic Transmitter for Aquatic Animals

    OpenAIRE

    Huidong Li; Chuan Tian; Jun Lu; Myjak, Mitchell J.; Martinez, Jayson J.; Brown, Richard S.; Zhiqun Daniel Deng

    2016-01-01

    Acoustic telemetry is the primary method to actively track aquatic animals for behavioral studies. However, the small storage capacities of the batteries used in the transmitters limit the time that the implanted animals can be studied. In this research, we developed and implemented a battery-free acoustic transmitter that uses a flexible piezoelectric beam to harvest energy from fish swimming as the power source. The transmitter sends out a unique identification code with a sufficiently stro...

  4. Climbing fiber-evoked endocannabinoid signaling heterosynaptically suppresses presynaptic cerebellar long-term potentiation

    NARCIS (Netherlands)

    B.J. van Beugen (Boeke); R.Y. Nagaraja (Raghavendra); C.R.W. Hansel (Christian)

    2006-01-01

    textabstractEndocannabinoid signaling has been demonstrated to mediate depolarization-induced suppression of excitation at climbing fiber (CF) and parallel fiber (PF) synapses onto cerebellar Purkinje cells. Here, we show that CF-evoked release of cannabinoids (CBs) additionally suppresses a

  5. Ocular Vestibular Evoked Myogenic Potentials

    Directory of Open Access Journals (Sweden)

    Felipe, Lilian

    2014-01-01

    Full Text Available Introduction Diagnostic testing of the vestibular system is an essential component of treating patients with balance dysfunction. Until recently, testing methods primarily evaluated the integrity of the horizontal semicircular canal, which is only a portion of the vestibular system. Recent advances in technology have afforded clinicians the ability to assess otolith function through vestibular evoked myogenic potential (VEMP testing. VEMP testing from the inferior extraocular muscles of the eye has been the subject of interest of recent research. Objective To summarize recent developments in ocular VEMP testing. Results Recent studies suggest that the ocular VEMP is produced by otolith afferents in the superior division of the vestibular nerve. The ocular VEMP is a short latency potential, composed of extraocular myogenic responses activated by sound stimulation and registered by surface electromyography via ipsilateral otolithic and contralateral extraocular muscle activation. The inferior oblique muscle is the most superficial of the six extraocular muscles responsible for eye movement. Therefore, measurement of ocular VEMPs can be performed easily by using surface electrodes on the skin below the eyes contralateral to the stimulated side. Conclusion This new variation of the VEMP procedure may supplement conventional testing in difficult to test populations. It may also be possible to use this technique to evaluate previously inaccessible information on the vestibular system.

  6. Evoked cavernous activity: neuroanatomic implications.

    Science.gov (United States)

    Yilmaz, U; Vicars, B; Yang, C C

    2009-01-01

    We investigated the autonomic innervation of the penis by using evoked cavernous activity (ECA). We recruited seven men with thoracic spinal cord injury (SCI) and sexual dysfunction, and six men who were scheduled to have pelvic surgery (PS), specifically non-nerve-sparing radical cystoprostatectomy. In the PS patients, ECA was performed both pre- and postoperatively. The left median nerve was electrically stimulated and ECA was recorded with two concentric electromyography needles placed into the right and left cavernous bodies. We simultaneously recorded hand and foot sympathetic skin responses (SSRs) as controls. In the SCI group, all but one patient had reproducible hand SSRs. None of these patients had ECA or foot SSRs. All the PS patients had reproducible ECA and SSRs, both preoperatively and postoperatively. There was no difference in the latency and amplitude measurements of ECA and SSRs in the postoperative compared with that of the pre-operative period (P>0.05). In conclusion, ECA is absent in men with SCI above the sympathetic outflow to the genitalia. In men, after radical pelvic surgery, ECA is preserved, indicating the preservation of sympathetic fibers.

  7. Optical Transmitter Terminal for Selective RF High Frequency Bans Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of the proposal work is to investigate the highly innovative conceptual design of an optical communication selective frequency transmitter terminal...

  8. Opportunistic transmitter selection for selfless overlay cognitive radios

    KAUST Repository

    Shaqfeh, Mohammad

    2013-11-01

    We propose an opportunistic strategy to grant channel access to the primary and secondary transmitters in causal selfless overlay cognitive radios over block-fading channels. The secondary transmitter helps the primary transmitter by relaying the primary messages opportunistically, aided by a buffer to store the primary messages temporarily. The optimal channel-aware transmitter- selection strategy is the solution of the maximization of the average secondary rate under the average primary rate requirement and the buffer stability constraints. Numerical results demonstrate the gains of the proposed opportunistic selection strategy. © 2013 IEEE.

  9. Determination and application of location and angular orientation of a pill transmitter within a body

    Science.gov (United States)

    Schipper, John F. (Inventor)

    2009-01-01

    A mobile pill transmitter system that moves through or adjacent to one or more organs in an animal's body and that provides signals from which the pill's present location and/or present angular orientation can be determined. The system also provides signals from which the present roll angle of the pill, about a selected axis, can be determined. When the location coordinates and the roll angle of the pill are within selected ranges, an aperture on the pill container releases a selected chemical into or onto the body. Optionally, the pill as it moves also provides a sequence of visually perceptible images; the times for image formation may correspond to times at which the pill transmitter system location or image satisfies one or at least four different criteria.

  10. Evoked potentials in neuroinfections in children

    Directory of Open Access Journals (Sweden)

    V. N. Komantsev

    2013-01-01

    Full Text Available We present the results of the neurophysiological study in which 95 children with viral encephalitis and 30 children with meningitis (age from 2 up to 17 years undergo evoked potentials investigation. Some specific features of evoked potentials in neuroinfections have been shown to correlate with the course of disease and the age of the patients. We give a description of a logistic model of predicting outcomes in such patients by complex diagnostic method. We have found that evoked potentials may be successfully implemented in correcting the therapeutic strategies. Study of evoked potentials in neuroinfections in children can define the severity and extent of lesions and help to identify subclinical dysfunction and monitor the recovery processes under the therapy.

  11. Visual Evoked Potentials in Rett Syndrome

    Directory of Open Access Journals (Sweden)

    J. Gordon Millichap

    2015-11-01

    Full Text Available Investigators from the Boston Children's Hospital recorded pattern-reversal visual evoked potentials (VEPs in Mecp2 heterozygous female mice and in 34 girls with Rett syndrome (RTT.

  12. An Energy Harvesting Underwater Acoustic Transmitter for Aquatic Animals

    Energy Technology Data Exchange (ETDEWEB)

    Li, Huidong; Tian, Chuan; Lu, Jun; Myjak, Mitchell J.; Martinez, Jayson J.; Brown, Richard S.; Deng, Zhiqun

    2016-09-20

    This paper presents a self-powered underwater acoustic transmitter using a piezoelectric beam to harvest the mechanical energy from fish swimming. This transmitter does not require a battery and is demonstrated in live fish. It transmits an acoustic waveform as the implanted fish swims. It enables long-term monitoring of aquatic animals.

  13. Evaluation of vaginal implant transmitters in elk (Cervus elaphus nelsoni).

    Science.gov (United States)

    Bruce K. Johnson; Terrance McCoy; Christopher O. Kochanny; Rachel C. Cook

    2006-01-01

    The effects of vaginal implant transmitters for tissue damage after 11 wk in 13 captive adult elk (Cervus elaphus nelsoni) and subsequent reproductive performance in 38 free-ranging elk were evaluated. Vaginal implant transmitters are designed to be shed at parturition and are used to locate birth sites of wild ungulates; however, potential adverse...

  14. 47 CFR 22.165 - Additional transmitters for existing systems.

    Science.gov (United States)

    2010-10-01

    .... (b) Antenna structure registration. Certain antenna structures must be registered with the Commission... contours of the additional transmitter(s) must be totally encompassed by the composite interfering contour... composite service area contour and predicted interfering contour, respectively, of the existing station on...

  15. Juvenile Salmon Acoustic Telemetry System Transmitter Downsize Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, Thomas J.; Myjak, Mitchell J.

    2010-04-30

    At the request of the U.S. Army Corps of Engineers, Portland District, researchers from Pacific Northwest National Laboratory investigated the use of an application-specific integrated circuit (ASIC) to reduce the weight and volume of Juvenile Salmon Acoustic Telemetry System (JSATS) transmitters while retaining current functionality. Review of the design of current JSATS transmitters identified components that could be replaced by an ASIC while retaining the function of the current transmitter and offering opportunities to extend function if desired. ASIC design alternatives were identified that could meet transmitter weight and volume targets of 200 mg and 100 mm3. If alternatives to the cylindrical batteries used in current JSATS transmitters can be identified, it could be possible to implant ASIC-based JSATS transmitters by injection rather than surgery. Using criteria for the size of fish suitable for surgical implantation of current JSATS transmitters, it was concluded that fish as small as 70 mm in length could be implanted with an ASIC-based transmitter, particularly if implantation by injection became feasible.

  16. 47 CFR 95.639 - Maximum transmitter power.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Maximum transmitter power. 95.639 Section 95.639 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES... (ERP). (e) The maximum transmitter output power authorized for LPRS stations is 100 mW. (f) In the Med...

  17. luminous transmittance and phase transition temperature of vo2:ce ...

    African Journals Online (AJOL)

    nb

    A two-step increase in transmittance observed in the cooling loop in pure VO2 was found to be suppressed by cerium inclusion. Keywords: vanadium dioxide, luminous transmittance, phase transition temperature. INTRODUCTION. Discovery of novel behavior of vanadium dioxide to undergo a metal-to-insulator phase.

  18. 47 CFR 25.281 - Automatic Transmitter Identification System (ATIS).

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Automatic Transmitter Identification System... Identification System (ATIS). All satellite uplink transmissions carrying broadband video information shall be identified through the use of an automatic transmitter identification system as specified below. (a...

  19. 47 CFR 90.473 - Operation of internal transmitter control systems through licensed fixed control points.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Operation of internal transmitter control... Transmitter Control Internal Transmitter Control Systems § 90.473 Operation of internal transmitter control systems through licensed fixed control points. An internal transmitter control system may be operated...

  20. Light transmittance and polymerization kinetics of amorphous calcium phosphate composites.

    Science.gov (United States)

    Par, Matej; Marovic, Danijela; Skenderovic, Hrvoje; Gamulin, Ozren; Klaric, Eva; Tarle, Zrinka

    2017-05-01

    This study investigated light transmittance and polymerization kinetics of experimental remineralizing composite materials based on amorphous calcium phosphate (ACP), reinforced with inert fillers. Light-curable composites were composed of Bis-EMA-TEGDMA-HEMA resin and ACP, barium glass, and silica fillers. Additionally, a commercial composite Tetric EvoCeram was used as a reference. Light transmittance was recorded in real-time during curing, and transmittance curves were used to assess polymerization kinetics. To obtain additional information on polymerization kinetics, temperature rise was monitored in real-time during curing and degree of conversion was measured immediately and 24 h post-cure. Light transmittance values of 2-mm thick samples of uncured ACP composites (2.3-2.9 %) were significantly lower than those of the commercial composite (3.8 %). The ACP composites presented a considerable transmittance rise during curing, resulting in post-cure transmittance values similar to or higher than those of the commercial composite (5.5-7.9 vs. 5.4 %). The initial part of light transmittance curves of experimental composites showed a linear rise that lasted for 7-20 s. Linear fitting was performed to obtain a function whose slope was assessed as a measure of polymerization rate. Comparison of transmittance and temperature curves showed that the linear transmittance rise lasted throughout the most part of the pre-vitrification period. The linear rise of light transmittance during curing has not been reported in previous studies and may indicate a unique kinetic behavior, characterized by a long period of nearly constant polymerization rate. The observed kinetic behavior may result in slower development of polymerization shrinkage stress but also inferior mechanical properties.

  1. Trachynilysin mediates SNARE-dependent release of catecholamines from chromaffin cells via external and stored Ca2+.

    Science.gov (United States)

    Meunier, F A; Mattei, C; Chameau, P; Lawrence, G; Colasante, C; Kreger, A S; Dolly, J O; Molgó, J

    2000-04-01

    Trachynilysin, a 159 kDa dimeric protein purified from stonefish (Synanceia trachynis) venom, dramatically increases spontaneous quantal transmitter release at the frog neuromuscular junction, depleting small clear synaptic vesicles, whilst not affecting large dense core vesicles. The basis of this insensitivity of large dense core vesicles exocytosis was examined using a fluorimetric assay to determine whether the toxin could elicit catecholamine release from bovine chromaffin cells. Unlike the case of the motor nerve endings, nanomolar concentrations of trachynilysin evoked sustained Soluble N-ethylmaleimide-sensitive fusion protein Attachment Protein REceptor-dependent exocytosis of large dense core vesicles, but only in the presence of extracellular Ca2+. However, this response to trachynilysin does not rely on Ca2+ influx through voltage-activated Ca2+ channels because the secretion was only slightly affected by blockers of L, N and P/Q types. Instead, trachynilysin elicited a localized increase in intracellular fluorescence monitored with fluo-3/AM, that precisely co-localized with the increase of fluorescence resulting from caffeine-induced release of Ca2+ from intracellular stores. Moreover, depletion of the latter stores inhibited trachynilysin-induced exocytosis. Thus, the observed requirement of external Ca2+ for stimulation of large dense core vesicles exocytosis from chromaffin cells implicates plasma membrane channels that signal efflux of Ca2+ from intracellular stores. This study also suggests that the bases of exocytosis of large dense core vesicles from motor nerve terminals and neuroendocrine cells are distinct.

  2. Emergency Locator Transmitter Survivability and Reliability Study

    Science.gov (United States)

    Stimson, Chad M.; Littell, Justin D.; Mazzuca, Lisa M.; Foster, Anthony W.; Theodorakos, George J.

    2017-01-01

    A comprehensive study of Emergency Locator Transmitter (ELT) performance was conducted over a three year period concluding in 2016 in support of the Search and Rescue (SAR) Mission Office at National Aeronautics and Space Administration (NASA) Goddard Space Flight Center (GSFC). The study began with a review of reported performance cited in a collection of works published as early as 1980 as well as analysis of a focused set of contemporary aviation crash reports. Based on initial research findings, a series of subscale and fullscale system tests were performed at NASA Langley Research Center (LaRC) with the goals of investigating ELT system failure modes and developing recommended improvements to the Radio Technical Commission for Aeronautics (RTCA) Minimum Operational Performance Specification (MOPS) that will result in improved system performance. Enhanced performance of ELT systems in aviation accidents will reduce unnecessary loss of human life and make SAR operations safer and less costly by reducing the amount of time required to locate accident sites.

  3. High energy microlaser and compact MOPA transmitter

    Science.gov (United States)

    Brickeen, Brian K.; Bernot, Dave; Geathers, Eliot; Mosovsky, Joseph

    2011-06-01

    A compact micro-oscillator incorporating a dual-bounce, grazing incidence gain module with a folded resonator cavity is presented. The gain module, previously developed for Nd:YVO4, is embodied in highly doped ceramic Nd:YAG to generate improved Q-switch performance while maintaining localized pump absorption. The cavity design utilizes a doubly folded optics path around the gain crystal to increase the intra-cavity mode for a more optimum overlap with the pump light volume produced by standard lensed laser diode bars. A modified CS-package diode mount is developed to facilitate the reduced size of the oscillator without sacrificing the ability to use a high-energy, side-pumping arrangement. The oscillator is combined with a high gain, high energy extraction VHGM amplifier to generate a transmitter source on the order of 50 mJ. Cooling for both the oscillator and amplifier modules is provided via a conductive path through the base of the package. Both devices are mounted on opposite sides of a phase-change cooling reservoir to enable self-contained, burst-mode operation. Beam shaping of the oscillator output, in preparation for injection into the amplifier, is contained in a small cut-away path on the reservoir side.

  4. MST radar transmitter control and monitor system

    Science.gov (United States)

    Brosnahan, J. W.

    1983-01-01

    A generalized transmitter control and monitor card was developed using the Intel 8031 (8051 family) microprocessor. The design was generalized so that this card can be utilized for virtually any control application with only firmware changes. The block diagram appears in Figure 2. The card provides for local control using a 16 key keypad (up to 64 keys are supported). The local display is four digits of 7 segment LEDs. The display can indicate the status of all major system parameters and provide voltage readout for the analog signal inputs. The card can be populated with only the chips required for a given application. Fully populated, the card has two RS-232 serial ports for computer communications. It has a total of 48 TTL parallel lines that can define as either inputs or outputs in groups of four. A total of 32 analog inputs with a 0-5 volt range are supported. In addition, a real-time clock/calendar is available if required. A total of 16 k bytes of ROM and 16 k bytes of RAM is available for programming. This card can be the basis of virtually any monitor or control system with appropriate software.

  5. Use of electricity to sedate Lake Trout for intracoelomic implantation of electronic transmitters

    Science.gov (United States)

    Faust, Matthew D.; Vandergoot, Christopher; Hostnik, Eric T.; Binder, Thomas R.; Mida Hinderer, Julia L.; Ives, Jessica T.; Krueger, Charles C.

    2017-01-01

    Use of telemetry data to inform fisheries conservation and management is becoming increasingly common; as such, fish typically must be sedated before surgical implantation of transmitters into the coelom. Given that no widely available, immediate-release chemical sedative currently exists in North America, we investigated the feasibility of using electricity to sedate Lake Trout Salvelinus namaycush long enough for an experienced surgeon to implant an electronic transmitter (i.e., 180 s). Specifically, our study objectives were to determine (1) whether some combination of electrical waveform characteristics (i.e., duty cycle, frequency, voltage, and pulse type) could sedate Lake Trout for at least 180 s; and (2) whether Lake Trout that were sequentially exposed to continuous DC and pulsed DC had greater rates of spinal injury and short-term mortality than control fish. A Portable Electrosedation System unit was used to sedate hatchery and wild Lake Trout. Dual-frequency pulsed-DC and two-stage approaches successfully sedated Lake Trout and had similar induction and recovery times. Lake Trout sedated using the two-stage approach did not have survival rates or spinal abnormalities that were significantly different from those of control fish. We concluded that electricity was a viable alternative to chemical sedatives for sedating Lake Trout before surgical implantation of an electronic transmitter, but we suggest that Lake Trout and other closely related species (e.g., Arctic Char Salvelinus alpinus) may require morphotype-specific electrical waveforms due to their morphological diversity.

  6. Pyrolyzed Photoresist Electrodes for Integration in Microfluidic Chips for Transmitter Detection from Biological Cells

    DEFF Research Database (Denmark)

    Larsen, Simon Tylsgaard; Argyraki, Aikaterini; Amato, Letizia

    2013-01-01

    In this study, we show how pyrolyzed photoresist carbon electrodes can be used for amperometric detection of potassium-induced transmitter release from large groups of neuronal PC 12 cells. This opens the way for the use of carbon film electrodes in microfabricated devices for neurochemical drug...... screening applications. We also investigated the effect of using two different photoresists for fabrication of pyrolyzed photoresist electrodes. We observed a significant difference in the cross-sectional profile of band electrodes made of AZ 4562 and AZ 5214 photoresist. This difference can be explained...

  7. Characterization of music-evoked autobiographical memories.

    Science.gov (United States)

    Janata, Petr; Tomic, Stefan T; Rakowski, Sonja K

    2007-11-01

    Despite music's prominence in Western society and its importance to individuals in their daily lives, very little is known about the memories and emotions that are often evoked when hearing a piece of music from one's past. We examined the content of music-evoked autobiographical memories (MEAMs) using a novel approach for selecting stimuli from a large corpus of popular music, in both laboratory and online settings. A set of questionnaires probed the cognitive and affective properties of the evoked memories. On average, 30% of the song presentations evoked autobiographical memories, and the majority of songs also evoked various emotions, primarily positive, that were felt strongly. The third most common emotion was nostalgia. Analyses of written memory reports found both general and specific levels of autobiographical knowledge to be represented, and several social and situational contexts for memory formation were common across many memories. The findings indicate that excerpts of popular music serve as potent stimuli for studying the structure of autobiographical memories.

  8. Isoflurane reduces the carbachol-evoked Ca2+ influx in neuronal cells.

    Science.gov (United States)

    Corrales, Alexandra; Xu, Fang; Garavito-Aguilar, Zayra V; Blanck, Thomas J J; Recio-Pinto, Esperanza

    2004-10-01

    The authors previously reported that the isoflurane-caused reduction of the carbachol-evoked cytoplasmic Ca transient increase ([Ca]cyt) was eliminated by K or caffeine-pretreatment. In this study the authors investigated whether the isoflurane-sensitive component of the carbachol-evoked [Ca]cyt transient involved Ca influx through the plasma membrane. Perfused attached human neuroblastoma SH-SY5Y cells were exposed to carbachol (1 mm, 2 min) in the absence and presence of isoflurane (1 mm) and in the absence and presence of extracellular Ca (1.5 mm). The authors studied the effect of the nonspecific cationic channel blocker La (100 microm), of the L-type Ca channel blocker nitrendipine (10 microm), and of the N-type Ca channel blocker omega-conotoxin GVIA (0.1 microm) on isoflurane modulation of the carbachol-evoked [Ca]cyt transient. [Ca]cyt was detected with fura-2 and experiments were carried out at 37 degrees C. Isoflurane reduced the peak and area of the carbachol-evoked [Ca]cyt transient in the presence but not in the absence of extracellular Ca. La had a similar effect as the removal of extracellular Ca. Omega-conotoxin GVIA and nitrendipine did not affect the isoflurane sensitivity of the carbachol response although nitrendipine reduced the magnitude of the carbachol response. The current data are consistent with previous observations in that the carbachol-evoked [Ca]cyt transient involves both Ca release from intracellular Ca stores and Ca entry through the plasma membrane. It was found that isoflurane attenuates the carbachol-evoked Ca entry. The isoflurane sensitive Ca entry involves a cationic channel different from the L- or N- type voltage-dependent Ca channels. These results indicate that isoflurane attenuates the carbachol-evoked [Ca]cyt transient at a site at the plasma membrane that is distal to the muscarinic receptor.

  9. Optical Tunable-Based Transmitter for Multiple Radio Frequency Bands

    Science.gov (United States)

    Nguyen, Hung (Inventor); Simons, Rainee N. (Inventor); Wintucky, Edwin G. (Inventor); Freeman, Jon C. (Inventor)

    2016-01-01

    An optical tunable transmitter is used to transmit multiple radio frequency bands on a single beam. More specifically, a tunable laser is configured to generate a plurality of optical wavelengths, and an optical tunable transmitter is configured to modulate each of the plurality of optical wavelengths with a corresponding radio frequency band. The optical tunable transmitter is also configured to encode each of the plurality of modulated optical wavelengths onto a single laser beam for transmission of a plurality of radio frequency bands using the single laser beam.

  10. Synaptically evoked glutamate transporter currents in Spinal Dorsal Horn Astrocytes

    Directory of Open Access Journals (Sweden)

    Dougherty Patrick M

    2009-07-01

    Full Text Available Abstract Background Removing and sequestering synaptically released glutamate from the extracellular space is carried out by specific plasma membrane transporters that are primarily located in astrocytes. Glial glutamate transporter function can be monitored by recording the currents that are produced by co-transportation of Na+ ions with the uptake of glutamate. The goal of this study was to characterize glutamate transporter function in astrocytes of the spinal cord dorsal horn in real time by recording synaptically evoked glutamate transporter currents. Results Whole-cell patch clamp recordings were obtained from astrocytes in the spinal substantia gelatinosa (SG area in spinal slices of young adult rats. Glutamate transporter currents were evoked in these cells by electrical stimulation at the spinal dorsal root entry zone in the presence of bicuculline, strychnine, DNQX and D-AP5. Transporter currents were abolished when synaptic transmission was blocked by TTX or Cd2+. Pharmacological studies identified two subtypes of glutamate transporters in spinal astrocytes, GLAST and GLT-1. Glutamate transporter currents were graded with stimulus intensity, reaching peak responses at 4 to 5 times activation threshold, but were reduced following low-frequency (0.1 – 1 Hz repetitive stimulation. Conclusion These results suggest that glutamate transporters of spinal astrocytes could be activated by synaptic activation, and recording glutamate transporter currents may provide a means of examining the real time physiological responses of glial cells in spinal sensory processing, sensitization, hyperalgesia and chronic pain.

  11. Experimental Characterization of Near-Infrared Laser Energy Absorption, Scattering, and Transmittance in Biological Tissue

    National Research Council Canada - National Science Library

    Laffitte, John; Roelant, David; Denton, Michael L; Thomas, Robert J

    2007-01-01

    .... Tissue samples varied in thickness from millimeters to microns. Readings from three IR detectors were used to calculate the diffuse reflectance, diffuse transmittance, and collimated transmittance...

  12. Brain correlates of music-evoked emotions.

    Science.gov (United States)

    Koelsch, Stefan

    2014-03-01

    Music is a universal feature of human societies, partly owing to its power to evoke strong emotions and influence moods. During the past decade, the investigation of the neural correlates of music-evoked emotions has been invaluable for the understanding of human emotion. Functional neuroimaging studies on music and emotion show that music can modulate activity in brain structures that are known to be crucially involved in emotion, such as the amygdala, nucleus accumbens, hypothalamus, hippocampus, insula, cingulate cortex and orbitofrontal cortex. The potential of music to modulate activity in these structures has important implications for the use of music in the treatment of psychiatric and neurological disorders.

  13. Evoking prescribed spike times in stochastic neurons

    Science.gov (United States)

    Doose, Jens; Lindner, Benjamin

    2017-09-01

    Single cell stimulation in vivo is a powerful tool to investigate the properties of single neurons and their functionality in neural networks. We present a method to determine a cell-specific stimulus that reliably evokes a prescribed spike train with high temporal precision of action potentials. We test the performance of this stimulus in simulations for two different stochastic neuron models. For a broad range of parameters and a neuron firing with intermediate firing rates (20-40 Hz) the reliability in evoking the prescribed spike train is close to its theoretical maximum that is mainly determined by the level of intrinsic noise.

  14. 47 CFR 95.628 - MedRadio transmitters.

    Science.gov (United States)

    2010-10-01

    ... measured on a test site equivalent to free space such as a fully anechoic test chamber. Compliance with the... anechoic test chamber. Compliance with the maximum transmitter power requirements set forth in § 95.639(f...

  15. High Temperature Telemetry Transmitter for Venus Exploration Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed S-band telemetry transmitter will operate in the exterior Venusian corrosive, high pressure, 460oC ambient atmosphere without being contained in a...

  16. Surgical insertions of transmitters and telemetry methods in fisheries research

    Science.gov (United States)

    Wargo Rub, A. Michelle; Jepsen, Niels; Liedtke, Theresa L.; Moser, L; Weber III, E. P. Scott

    2015-01-01

    Use of electronic transmitter and monitoring systems to track movements of aquatic animals has increased continuously since the inception of these systems in the mid-1950s. The purpose of the present report is to provide information about veterinary principles and their incorporation into surgical implantation procedures for fish. We also intend to provide insight into the unique challenges of field-based aquatic surgical studies. Within this context, 4 aspects of the process for surgical implantation of transmitters in fish (ie, handling, aseptic technique, anesthesia, and implantation) will be described. Effects of surgical insertion of transmitters (ie, tagging) and aspects of the surgical implantation process where collaboration and professional exchanges among nonveterinarian researchers and veterinarians may be most fruitful will be discussed. Although this report focuses on surgical implantation, the principles and protocols described here (other than incision and suture placement) are also applicable to studies that involve injection of transmitters into fish.

  17. Determining Light Transmittance Characteristics of Wood and Bark Chips

    Science.gov (United States)

    Douglas B. Brumm; Robert C. Radcliffe; John A. Sturos

    1983-01-01

    Describes compter-assisted testing for measuring light transmittance of wood and bark chips. Electronic interface permitted the computer to collect physical data accurately and efficiently and to analyze and present the data in several tabular and grapical formats

  18. High Temperature Telemetry Transmitter for Venus Exploration Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed S-band telemetry transmitter will operate in the exterior Venusian high pressure, 465?aC ambient atmosphere without being contained in a thermally...

  19. Streaming Transmitter over Block-Fading Channels with Delay Constraint

    CERN Document Server

    Cocco, Giuseppe; Ibars, Christian

    2012-01-01

    Data streaming transmission, in which the data arrives at the transmitter gradually over time is studied. It is assumed that the transmitter receives a new message at each channel block at a constant rate which is fixed by an underlying application, and tries to broadcast these messages to users within a certain deadline. The channels are assumed to be block fading and independent over blocks and users. The performance measure is the average total rate of received information at the users within the transmission deadline. Three different encoding schemes are proposed and compared with an informed transmitter upper bound in terms of the average total rate for a set of users with varying channel qualities. Analytical upper bounds on the average total rate are derived for all the proposed schemes. It is shown that no single transmission strategy dominates the others at all channel settings, and the best transmitter streaming scheme depends on the distribution of the average channel conditions over the users.

  20. Efficient and Compact Semiconductor Laser Transmitter Modules Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Continue development of a Compact Transmitter Module (CTM). Modules will be voltage controlled to adjust wavlength using temperature and drive current settings. The...

  1. Transmitter Architectures Based on Near-Field Direct Antenna Modulation

    OpenAIRE

    Babakhani, Aydin; Rutledge, David B.; Hajimiri, Ali

    2008-01-01

    A near-field direct antenna modulation (NFDAM) technique is introduced, where the radiated far-field signal is modulated by time-varying changes in the antenna near-field electromagnetic (EM) boundary conditions. This enables the transmitter to send data in a direction-dependent fashion producing a secure communication link. Near-field direct antenna modulation (NFDAM) can be performed by using either switches or varactors. Two fully-integrated proof-of-concept NFDAM transmitters operating at...

  2. An Ultra-Low Power Edge Combining BPSK Transmitter

    Science.gov (United States)

    2013-09-01

    TECHNICAL DOCUMENT 3271 September 2013 An Ultra-Low Power Edge Combining BPSK Transmitter A. Ryu J. Rowland S. Naik...Ultra-Low Power Edge Combining BPSK Transmitter Albert Ryu #1, Jason Rowland #2, Suketu Naik #3 #1, #2 55250, Advanced Integrated Circuit Technology...locked to a ring oscillator (RO), and then multiple phase outputs are combined at the last edge combining/power amplifier (EC/PA) stage. With the

  3. Glutamate acts as a neurotransmitter for gastrin releasing peptide-sensitive and insensitive itch-related synaptic transmission in mammalian spinal cord

    Directory of Open Access Journals (Sweden)

    Ling Jennifer

    2011-06-01

    Full Text Available Abstract Itch sensation is one of the major sensory experiences of human and animals. Recent studies have proposed that gastrin releasing peptide (GRP is a key neurotransmitter for itch in spinal cord. However, no direct evidence is available to indicate that GRP actually mediate responses between primary afferent fibers and dorsal horn neurons. Here we performed integrative neurobiological experiments to test this question. We found that a small population of rat dorsal horn neurons responded to GRP application with increases in calcium signaling. Whole-cell patch-clamp recordings revealed that a part of superficial dorsal horn neurons responded to GRP application with the increase of action potential firing in adult rats and mice, and these dorsal horn neurons received exclusively primary afferent C-fiber inputs. On the other hands, few Aδ inputs receiving cells were found to be GRP positive. Finally, we found that evoked sensory responses between primary afferent C fibers and GRP positive superficial dorsal horn neurons are mediated by glutamate but not GRP. CNQX, a blocker of AMPA and kainate (KA receptors, completely inhibited evoked EPSCs, including in those Fos-GFP positive dorsal horn cells activated by itching. Our findings provide the direct evidence that glutamate is the principal excitatory transmitter between C fibers and GRP positive dorsal horn neurons. Our results will help to understand the neuronal mechanism of itch and aid future treatment for patients with pruritic disease.

  4. Design Parameters of a Miniaturized Piezoelectric Underwater Acoustic Transmitter

    Energy Technology Data Exchange (ETDEWEB)

    Li, Huidong; Deng, Zhiqun; Yuan, Yong; Carlson, Thomas J.

    2012-07-02

    The Juvenile Salmon Acoustic Telemetry System (JSATS) project supported by the U.S. Army Corps of Engineers, Portland District, has yielded the smallest acoustic fish tag transmitter commercially available to date. In order to study even smaller fish populations and make the transmitter injectable by needles, the JSATS acoustic micro transmitter needs to be further downsized. As part of the transmitter downsizing effort some of the design parameters of the lead zirconate titanate (PZT) ceramic tube transducer in the transmitter were studied, including the type of PZT, the backing material, the necessary drive voltage, the transmitting bandwidth and the length of the transducer. It was found that, to satisfy the 156-dB source level requirement of JSATS, a square wave with a 10-volt amplitude is required to drive 'soft' PZT transducers. PZT-5H demonstrated the best source level performance. For Navy types I and II, 16 volts or 18 volts were needed. Ethylene-propylene-diene monomer (EPDM) closed-cell foam was found to be the backing material providing the highest source level. The effect of tube length on the source level is also demonstrated in this paper, providing quantitative information for downsizing of small piezoelectric transmitters.

  5. Effects of radio transmitters on migrating wood thrushes

    Science.gov (United States)

    Powell, L.A.; Krementz, D.G.; Lang, J.D.; Conroy, M.J.

    1998-01-01

    We quantified the effects of radio transmitters on Wood Thrushes (Hylocichla mustelina) using 4 yr of banding and telemetry data from Piedmont National Wildlife Refuge, Georgia. Flight performance models suggest that the 1.6-g transmitter shortens the migratory range of Wood Thrushes by only 60 km, and the estimated migratory range is adequate to accomplish migration even with limited fat stores. We used two strengths of line, 5- and 9-kg test-strength braided Dacron, to attach the transmitters using the thigh-harness method. We recaptured 13 returning radio-marked Wood Thrushes, seven of which were still marked. Six of the seven birds marked with the 5-kg test harnesses lost their transmitters within 1 yr while all six of the 9-kg test harnesses were still attached up to 21 mo later. Radio-marking did not reduce the return rates of adults and immatures, and the transmitters did not cause radio-marked birds to lose more mass than banded-only birds. Wood Thrushes can successfully carry a transmitter during migration with no detectable negative effects. We recommend continued use of the thigh-harness method, but we encourage the use of 5-kg cotton line.

  6. Evidence for a role of glutamate as an efferent transmitter in taste buds

    Directory of Open Access Journals (Sweden)

    Anderson Catherine B

    2010-06-01

    Full Text Available Abstract Background Glutamate has been proposed as a transmitter in the peripheral taste system in addition to its well-documented role as an umami taste stimulus. Evidence for a role as a transmitter includes the presence of ionotropic glutamate receptors in nerve fibers and taste cells, as well as the expression of the glutamate transporter GLAST in Type I taste cells. However, the source and targets of glutamate in lingual tissue are unclear. In the present study, we used molecular, physiological and immunohistochemical methods to investigate the origin of glutamate as well as the targeted receptors in taste buds. Results Using molecular and immunohistochemical techniques, we show that the vesicular transporters for glutamate, VGLUT 1 and 2, but not VGLUT3, are expressed in the nerve fibers surrounding taste buds but likely not in taste cells themselves. Further, we show that P2X2, a specific marker for gustatory but not trigeminal fibers, co-localizes with VGLUT2, suggesting the VGLUT-expressing nerve fibers are of gustatory origin. Calcium imaging indicates that GAD67-GFP Type III taste cells, but not T1R3-GFP Type II cells, respond to glutamate at concentrations expected for a glutamate transmitter, and further, that these responses are partially blocked by NBQX, a specific AMPA/Kainate receptor antagonist. RT-PCR and immunohistochemistry confirm the presence of the Kainate receptor GluR7 in Type III taste cells, suggesting it may be a target of glutamate released from gustatory nerve fibers. Conclusions Taken together, the results suggest that glutamate may be released from gustatory nerve fibers using a vesicular mechanism to modulate Type III taste cells via GluR7.

  7. Transient Evoked aotacoustic emissions otologically normal adults

    African Journals Online (AJOL)

    ABUTH

    Objective: To examine the effects of aging on the existence of transient evoked otoacoustic emissions in normal adult. Material and methods 40 ... wax or any middle ear pathology which might affect the recording at TEOAEs. After that, ... related to decreased hearing sensitivity and are independent of aging, Previous studies.

  8. Neural correlates of evoked phantom limb sensations.

    Science.gov (United States)

    Andoh, J; Diers, M; Milde, C; Frobel, C; Kleinböhl, D; Flor, H

    2017-05-01

    Previous work showed the existence of changes in the topographic organization within the somatosensory cortex (SI) in amputees with phantom limb pain, however, the link between nonpainful phantom sensations such as cramping or tingling or the percept of the limb and cortical changes is less clear. We used functional magnetic resonance imaging (fMRI) in a highly selective group of limb amputees who experienced inducible and reproducible nonpainful phantom sensations. A standardized procedure was used to locate body sites eliciting phantom sensations in each amputee. Selected body sites that could systematically evoke phantom sensations were stimulated using electrical pulses in order to induce phasic phantom sensations. Homologous body parts were also stimulated in a group of matched controls. Activations related to evoked phantom sensations were found bilaterally in SI and the intraparietal sulci (IPS), which significantly correlated with the intensity of evoked phantom sensations. In addition, we found differences in intra- and interhemispheric interaction between amputees and controls during evoked phantom sensations. We assume that phantom sensations might be associated with a functional decoupling between bilateral SI and IPS, possibly resulting from transcallosal reorganization mechanisms following amputation. Copyright © 2017. Published by Elsevier B.V.

  9. Glucagon-like peptide-2 modulates neurally evoked mucosal chloride secretion in guinea pig small intestine in vitro.

    Science.gov (United States)

    Baldassano, Sara; Liu, Sumei; Qu, Mei-Hu; Mulè, Flavia; Wood, Jackie D

    2009-10-01

    Glucagon-like peptide-2 (GLP-2) is an important neuroendocrine peptide in intestinal physiology. It influences digestion, absorption, epithelial growth, motility, and blood flow. We studied involvement of GLP-2 in intestinal mucosal secretory behavior. Submucosal-mucosal preparations from guinea pig ileum were mounted in Ussing chambers for measurement of short-circuit current (I(sc)) as a surrogate for chloride secretion. GLP-2 action on neuronal release of acetylcholine was determined with ELISA. Enteric neuronal expression of the GLP-2 receptor (GLP-2R) was studied with immunohistochemical methods. Application of GLP-2 (0.1-100 nM) to the serosal or mucosal side of the preparations evoked no change in baseline I(sc) and did not alter transepithelial ionic conductance. Transmural electrical field stimulation (EFS) evoked characteristic biphasic increases in I(sc), with an initially rapid rising phase followed by a sustained phase. Application of GLP-2 reduced the EFS-evoked biphasic responses in a concentration-dependent manner. The GLP-2R antagonist GLP-2-(3-33) significantly reversed suppression of the EFS-evoked responses by GLP-2. Tetrodotoxin, scopolamine, and hexamethonium, but not vasoactive intestinal peptide type 1 receptor (VPAC1) antagonist abolished or reduced to near zero the EFS-evoked responses. GLP-2 suppressed EFS-evoked acetylcholine release as measured by ELISA. Pretreatment with GLP-2-(3-33) offset this action of GLP-2. In the submucosal plexus, GLP-2R immunoreactivity (-IR) was expressed in choline acetyltransferase-IR neurons, somatostatin-IR neurons, neuropeptide Y-IR neurons, and vasoactive intestinal peptide-IR neurons. We conclude that submucosal neurons in the guinea pig ileum express GLP-2R. Activation of GLP-2R decreases neuronally evoked epithelial chloride secretion by suppressing acetylcholine release from secretomotor neurons.

  10. A standard operating procedure for the surgical implantation of transmitters in juvenile salmonids

    Science.gov (United States)

    Liedtke, T.L.; Beeman, J.W.; Gee, L.P.

    2012-01-01

    require large numbers of tagged fish. For example, a study conducted at the dams on the Columbia River and funded by the U.S. Army Corps of Engineers required tagging and monitoring of 40,000 juvenile salmon during a 3-month migration period (Counihan and others, 2006a, 2006b; Perry and others, 2006). To meet the demands of such a large study, the authors and CRRL staff refined the SOP to increase efficiency in the tagging process while maintaining high standards of fish care. The SOP has been used in laboratory and field settings for more than 15 years, and consistently has produced low mortality rates (hours after tagging. In addition to describing the detailed surgical procedures required for transmitter implantation, this document provides guidance on fish collection, handling and holding, and the release of tagged fish. Although often overlooked, or at least underemphasized, these processes can have a large impact on the outcome of the tagging procedure. Stress associated with the individual steps in handling and tagging can be cumulative and lethal (Maule and others, 1988; Wedemeyer and others, 1990; Portz and others, 2006), so the goal is to provide the best possible fish care at every step in order to manage the overall effect on study fish.

  11. Visually Evoked Spiking Evolves While Spontaneous Ongoing Dynamics Persist

    DEFF Research Database (Denmark)

    Huys, Raoul; Jirsa, Viktor K; Darokhan, Ziauddin

    2016-01-01

    attractor. Its existence guarantees that evoked spiking return to the spontaneous state. However, the spontaneous ongoing spiking state and the visual evoked spiking states are qualitatively different and are separated by a threshold (separatrix). The functional advantage of this organization...

  12. 47 CFR 90.471 - Points of operation in internal transmitter control systems.

    Science.gov (United States)

    2010-10-01

    ...) SAFETY AND SPECIAL RADIO SERVICES PRIVATE LAND MOBILE RADIO SERVICES Transmitter Control Internal Transmitter Control Systems § 90.471 Points of operation in internal transmitter control systems. The... licensee for internal communications and transmitter control purposes. Operating positions in internal...

  13. 47 CFR 90.475 - Operation of internal transmitter control systems in specially equipped systems.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Operation of internal transmitter control... Control Internal Transmitter Control Systems § 90.475 Operation of internal transmitter control systems in specially equipped systems. (a) An internal transmitter control system need not be designed to meet the...

  14. Mechanical stimulation evokes rapid increases in extracellular adenosine concentration in the prefrontal cortex

    Science.gov (United States)

    Ross, Ashley E.; Nguyen, Michael D.; Privman, Eve; Venton, B. Jill

    2014-01-01

    Mechanical perturbations can release ATP, which is broken down to adenosine. In this work, we used carbon-fiber microelectrodes and fast-scan cyclic voltammetry to measure mechanically-stimulated adenosine in the brain by lowering the electrode 50 μm. Mechanical stimulation evoked adenosine in vivo (average: 3.3 ± 0.6 μM) and in brain slices (average: 0.8 ± 0.1 μM) in the prefrontal cortex. The release was transient, lasting 18 ± 2 s. Lowering a 15 μm diameter glass pipette near the carbon-fiber microelectrode produced similar results as lowering the actual microelectrode. However, applying a small puff of artificial cerebral spinal fluid was not sufficient to evoke adenosine. Multiple stimulations within a 50 μm region of a slice did not significantly change over time or damage cells. Chelating calcium with EDTA or blocking sodium channels with tetrodotoxin (TTX) significantly decreased mechanically evoked adenosine, signifying that the release is activity-dependent. An alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA) receptor antagonist, 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX), did not affect mechanically-stimulated adenosine; however, the nucleoside triphosphate diphosphohydrolase 1,2 and 3 (NTDPase) inhibitor POM-1 significantly reduced adenosine so a portion of adenosine is dependent on extracellular ATP metabolism. Thus, mechanical perturbations from inserting a probe in the brain cause rapid, transient adenosine signaling which might be neuroprotective. PMID:24606335

  15. Wiener kernel analysis of a noise-evoked otoacoustic emission

    NARCIS (Netherlands)

    van Dijk, P; Maat, A; Wit, H P

    1997-01-01

    In one specimen of the frog species, Rana esculenta, the following were measured: (1) a spontaneous otoacoustic emission; (2) a click-evoked otoacoustic emissions; and (3) a noise evoked otoacoustic emission. From the noise evoked emission response, a first-and a second-order Wiener kernel and the

  16. An Energy Harvesting Underwater Acoustic Transmitter for Aquatic Animals.

    Science.gov (United States)

    Li, Huidong; Tian, Chuan; Lu, Jun; Myjak, Mitchell J; Martinez, Jayson J; Brown, Richard S; Deng, Zhiqun Daniel

    2016-09-20

    Acoustic telemetry is the primary method to actively track aquatic animals for behavioral studies. However, the small storage capacities of the batteries used in the transmitters limit the time that the implanted animals can be studied. In this research, we developed and implemented a battery-free acoustic transmitter that uses a flexible piezoelectric beam to harvest energy from fish swimming as the power source. The transmitter sends out a unique identification code with a sufficiently strong signal (150 dB, ref: 1 μPa at 1 meter) that has a detection range of up to 100 meters. Two prototypes, 100 mm and 77 mm long, respectively, weighing only about 1 gram or less in air, were sub-dermally implanted in two species of live fish. Transmissions were successfully detected as the fish swam in a natural manner. This represents the first known implanted energy-harvesting transmitter demonstrated in vivo. Successful development of this transmitter greatly expands the potential for long-term studies of the behaviors of aquatic animals and for subsequently developing strategies to mitigate the environmental impacts of renewable energy systems.

  17. Microminiature radio frequency transmitter for communication and tracking applications

    Science.gov (United States)

    Crutcher, Richard I.; Emery, Mike S.; Falter, Kelly G.; Nowlin, C. H.; Rochelle, Jim M.; Clonts, Lloyd G.

    1997-02-01

    A micro-miniature radio frequency (rf) transmitter has been developed and demonstrated by the Oak Ridge National Laboratory. The objective of the rf transmitter development was to maximize the transmission distance while drastically shrinking the overall transmitter size, including antenna. Based on analysis and testing, an application-specific integrated circuit (ASIC) with a 16-GHz gallium arsenide (GaAs) oscillator and integrated on-chip antenna was designed and fabricated using microwave monolithic integrated circuit (MMIC) technology. Details of the development and the results of various field tests are discussed. The rf transmitter is applicable to covert surveillance and tracking scenarios due to its small size of 2.2 multiplied by 2.2 mm, including the antenna. Additionally, the 16-GHz frequency is well above the operational range of consumer-grade radio scanners, providing a degree of protection from unauthorized interception. Variations of the transmitter design have been demonstrated for tracking and tagging beacons, transmission of digital data, and transmission of real-time analog video from a surveillance camera. Preliminary laboratory measurements indicate adaptability to direct-sequence spread-spectrum transmission, providing a low probability of intercept and/or detection. Concepts related to law enforcement applications are presented.

  18. An Energy Harvesting Underwater Acoustic Transmitter for Aquatic Animals

    Science.gov (United States)

    Li, Huidong; Tian, Chuan; Lu, Jun; Myjak, Mitchell J.; Martinez, Jayson J.; Brown, Richard S.; Deng, Zhiqun Daniel

    2016-09-01

    Acoustic telemetry is the primary method to actively track aquatic animals for behavioral studies. However, the small storage capacities of the batteries used in the transmitters limit the time that the implanted animals can be studied. In this research, we developed and implemented a battery-free acoustic transmitter that uses a flexible piezoelectric beam to harvest energy from fish swimming as the power source. The transmitter sends out a unique identification code with a sufficiently strong signal (150 dB, ref: 1 μPa at 1 meter) that has a detection range of up to 100 meters. Two prototypes, 100 mm and 77 mm long, respectively, weighing only about 1 gram or less in air, were sub-dermally implanted in two species of live fish. Transmissions were successfully detected as the fish swam in a natural manner. This represents the first known implanted energy-harvesting transmitter demonstrated in vivo. Successful development of this transmitter greatly expands the potential for long-term studies of the behaviors of aquatic animals and for subsequently developing strategies to mitigate the environmental impacts of renewable energy systems.

  19. Thought-evoking approaches in engineering problems

    CERN Document Server

    2014-01-01

    In creating the value-added product in not distant future, it is necessary and inevitable to establish a holistic and though-evoking approach to the engineering problem, which should be at least associated with the inter-disciplinary knowledge and thought processes across the whole engineering spheres. It is furthermore desirable to integrate it with trans-disciplinary aspects ranging from manufacturing culture, through liberal-arts engineering, and industrial sociology.   The thought-evoking approach can be exemplified and typified by representative engineering problems: unveiling essential features in ‘Tangential Force Ratio and Interface Pressure’, prototype development for ‘Bio-mimetic Needle’ and application of ‘Water-jet Machining to Artificial Hip Joint’, product innovation in ‘Heat Sink for Computer’, application of ‘Graph Theory’ to similarity evaluation of production systems, leverage among reciprocity attributes in ‘Industrial and Engineering Designs for Machine Enclosure’,...

  20. Music-Evoked Emotions-Current Studies.

    Science.gov (United States)

    Schaefer, Hans-Eckhardt

    2017-01-01

    The present study is focused on a review of the current state of investigating music-evoked emotions experimentally, theoretically and with respect to their therapeutic potentials. After a concise historical overview and a schematic of the hearing mechanisms, experimental studies on music listeners and on music performers are discussed, starting with the presentation of characteristic musical stimuli and the basic features of tomographic imaging of emotional activation in the brain, such as functional magnetic resonance imaging (fMRI) and positron emission tomography (PET), which offer high spatial resolution in the millimeter range. The progress in correlating activation imaging in the brain to the psychological understanding of music-evoked emotion is demonstrated and some prospects for future research are outlined. Research in psychoneuroendocrinology and molecular markers is reviewed in the context of music-evoked emotions and the results indicate that the research in this area should be intensified. An assessment of studies involving measuring techniques with high temporal resolution down to the 10 ms range, as, e.g., electroencephalography (EEG), event-related brain potentials (ERP), magnetoencephalography (MEG), skin conductance response (SCR), finger temperature, and goose bump development (piloerection) can yield information on the dynamics and kinetics of emotion. Genetic investigations reviewed suggest the heredity transmission of a predilection for music. Theoretical approaches to musical emotion are directed to a unified model for experimental neurological evidence and aesthetic judgment. Finally, the reports on musical therapy are briefly outlined. The study concludes with an outlook on emerging technologies and future research fields.

  1. Joint Transmitter-Receiver Optimization in the Downlink CDMA Systems

    Directory of Open Access Journals (Sweden)

    Mohammad Saquib

    2002-08-01

    Full Text Available To maximize the downlink code-division multiple access (CDMA system capacity, we propose to minimize the total transmitted power of the system subject to users′ signal-to-interference ratio (SIR requirements via designing optimum transmitter sequences and utilizing linear optimum receivers (minimum mean square error (MMSE receiver. In our work on joint transmitter-receiver design for the downlink CDMA systems with multiple antennas and multipath channels, we develop several optimization algorithms by considering various system constraints and prove their convergence. We empirically observed that under the optimization algorithm with no constraint on the system, the optimum receiver structure matches the received transmitter sequences. A simulation study is performed to see how the different practical system constraints penalize the system with respect to the optimum algorithm with no constraint on the system.

  2. Two-Photon Na+ Imaging Reports Somatically Evoked Action Potentials in Rat Olfactory Bulb Mitral and Granule Cell Neurites.

    Science.gov (United States)

    Ona-Jodar, Tiffany; Gerkau, Niklas J; Sara Aghvami, S; Rose, Christine R; Egger, Veronica

    2017-01-01

    Dendrodendritic synaptic interactions are a hallmark of neuronal processing in the vertebrate olfactory bulb. Many classes of olfactory bulb neurons including the principal mitral cells (MCs) and the axonless granule cells (GCs) dispose of highly efficient propagation of action potentials (AP) within their dendrites, from where they can release transmitter onto each other. So far, backpropagation in GC dendrites has been investigated indirectly via Ca2+ imaging. Here, we used two-photon Na+ imaging to directly report opening of voltage-gated sodium channels due to AP propagation in both cell types. To this end, neurons in acute slices from juvenile rat bulbs were filled with 1 mM SBFI via whole-cell patch-clamp. Calibration of SBFI signals revealed that a change in fluorescence ΔF/F by 10% corresponded to a Δ[Na+]i of ∼22 mM. We then imaged proximal axon segments of MCs during somatically evoked APs (sAP). While single sAPs were detectable in ∼50% of axons, trains of 20 sAPs at 50 Hz always resulted in substantial ΔF/F of ∼15% (∼33 mM Δ[Na+]i). ΔF/F was significantly larger for 80 Hz vs. 50 Hz trains, and decayed with half-durations τ1/2 ∼0.6 s for both frequencies. In MC lateral dendrites, AP trains yielded small ΔF/F of ∼3% (∼7 mM Δ[Na+]i). In GC apical dendrites and adjacent spines, single sAPs were not detectable. Trains resulted in an average dendritic ΔF/F of 7% (16 mM Δ[Na+]i) with τ1/2 ∼1 s, similar for 50 and 80 Hz. Na+ transients were indistinguishable between large GC spines and their adjacent dendrites. Cell-wise analysis revealed two classes of GCs with the first showing a decrease in ΔF/F along the dendrite with distance from the soma and the second an increase. These classes clustered with morphological parameters. Simulations of Δ[Na+]i replicated these behaviors via negative and positive gradients in Na+ current density, assuming faithful AP backpropagation. Such specializations of dendritic excitability might confer

  3. Examination of an optical transmittance test for photovoltaic encapsulation materials

    Energy Technology Data Exchange (ETDEWEB)

    Miller, David C.; Bengoechea, Jaione; Bokria, Jayesh G.; Köhl, Michael; Powell, Nick E.; Smith, Michael E.; White, Michael D.; Wilson, Helen Rose; Wohlgemuth, John H.; Dhere, Neelkanth G.; Wohlgemuth, John H.; Lynn, Kevin W.

    2013-09-24

    The optical transmittance of encapsulation materials is a key characteristic for their use in photovoltaic (PV) modules. Changes in transmittance with time in the field affect module performance, which may impact product warranties. Transmittance is important in product development, module manufacturing, and field power production (both immediate and long-term). Therefore, an international standard (IEC 62788-1-4) has recently been proposed by the Encapsulation Task-Group within the Working Group 2 (WG2) of the International Electrotechnical Commission (IEC) Technical Committee 82 (TC82) for the quantification of the optical performance of PV encapsulation materials. Existing standards, such as ASTM E903, are general and more appropriately applied to concentrated solar power than to PV. Starting from the optical transmittance measurement, the solar-weighted transmittance of photon irradiance, yellowness index (which may be used in aging studies to assess durability), and ultraviolet (UV) cut-off wavelength may all be determined using the proposed standard. The details of the proposed test are described. The results of a round-robin experiment (for five materials) conducted at seven laboratories to validate the test procedure using representative materials are also presented. For example, the Encapsulation Group actively explored the measurement requirements (wavelength range and resolution), the requirements for the spectrophotometer (including the integrating sphere and instrument accessories, such as a depolarizer), specimen requirements (choice of glass-superstrate and -substrate), and data analysis (relative to the light that may be used in the PV application). The round-robin experiment identified both intra- and inter-laboratory instrument precision and bias for five encapsulation materials (encompassing a range of transmittance and haze-formation characteristics).

  4. Luminous transmittance and phase transition temperature of VO 2 ...

    African Journals Online (AJOL)

    The phase transition temperature (τc) of the films was obtained from both the transmittance and sheet resistance against temperature curves. A change in sheet resistance of 2 to 3 orders of magnitude was observed for both undoped and Ce-doped VO2 films. Comparison between undoped and doped VO2 films revealed ...

  5. Snake mortality associated with late season radio-transmitter implantation

    Science.gov (United States)

    D. Craig Rudolph; Shirley J. Burgdorf; Richard R. Schaefer; Richard N. Conner; Robert T. Zappalorth

    1998-01-01

    Radio-telemetry is an increasingly used procedure to obtain data on the biology of free-living snakes (Reinert 1992, 1994). In Texas and Louisiana we have been using the surgical technique of Weatherhead and Anderka (1984) to implant transmitters in timber rattlesnakes (Crotalus horridus) and Louisiana pine snakes (Pituophis melanoleucus...

  6. 47 CFR 73.1660 - Acceptability of broadcast transmitters.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Acceptability of broadcast transmitters. 73.1660 Section 73.1660 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES RADIO BROADCAST SERVICES Rules Applicable to All Broadcast Stations § 73.1660 Acceptability of...

  7. Order-sorting filter transmittance measured with an array detector

    Science.gov (United States)

    Heaney, James B.; Bradley, Scott E.; Bly, Vincent T.; Ewin, Audrey J.; La, Anh T.

    1993-08-01

    The simultaneous measurement of the spectrally and spatially variant transmittance of a linear variable order-sorting filter in a manner that closely resembles its conditions of actual use is described. The transmittance of a prototype order-sorting filter was measured in the 400- to 880-nm wavelength region by illuminating it with the output beam of a spectrophotometer while the filter was attached to the front of a 30 x 32 pixel silicon array detector. The filter was designed to be used in the output beam of a grating spectrometer to prevent the dispersal of higher diffracted orders onto an array detector. Areas of the filter that were spatially matched to the corresponding detector pixel column had measured peak transmittances of about 90 percent that were uniform to within +/- 1.5 percent along a given column. Transmittances for incident wavelengths shorter than the desired bandpass, corresponding to the order overlap region, were measured in the 0.003 range. Line spread function measurements made with the array detector indicated no significant beam spreading caused by inserting the filter into the beam.

  8. 47 CFR 73.685 - Transmitter location and antenna system.

    Science.gov (United States)

    2010-10-01

    ... antenna system. In the case of a composite antenna composed of two or more individual antennas, this means that the patterns for the composite antenna, not the patterns for each of the individual antennas, must... 47 Telecommunication 4 2010-10-01 2010-10-01 false Transmitter location and antenna system. 73.685...

  9. Ozone transmittance in a model atmosphere at Ikeja, Lagos state ...

    African Journals Online (AJOL)

    Variation of ozone transmittance with height in the atmosphere for radiation in the 9.6m absorption band was studied using Goody's model atmosphere, with cubic spline interpolation technique to improve the quality of the curve. The data comprising of pressure and temperature at different altitudes (0-22 km) for the month of ...

  10. Analysis of an Intelligent Temperature Transmitter for Process Control

    African Journals Online (AJOL)

    It also identifies low power microprocessor and analog to digital converters working with the basic sensor circuit as the key propellants in the advancement of transmitter technology. Despite several sensors available in the process control industry, the authors focus on temperature sensors and analyze a typical Rosemount ...

  11. Digital staining of pathological tissue specimens using spectral transmittance

    Science.gov (United States)

    Bautista, Pinky A.; Abe, Tokiya; Yamaguchi, Masahiro; Yagi, Yukako; Ohyama, Nagaaki

    2005-04-01

    Staining of tissue specimens is a classical procedure in pathological diagnosis to enhance the contrast between tissue components such that identification and classification of these components can be easily performed. In this paper, a framework for digital staining of pathological specimens using the information derived from the L-band spectral transmittance of various pathological tissue components is introduced, particularly the transformation of a Hematoxylin and Eosin (HE) stained specimen to its Masson-Trichrome (MT) stained counterpart. The digital staining framework involves the classification of tissue components, which are highlighted when the specimen is actually stained with MT stain, e.g. fibrosis, from the HE-stained image; and the linear mapping between specific sets of HE and MT stained transmittance spectra through pseudo-inverse procedure to produce the LxL transformation matrices that will be used to transform the HE stained transmittance to its equivalent MT stained transmittance configuration. To generate the digitally stained image, the decisions of multiple quadratic classifiers are pooled to form the weighting factors for the transformation matrices. Initial results of our experiments on liver specimens show the viability of multispectral imaging (MSI) for the implementation of digital staining in the pathological context.

  12. Spectral transmittance of the spectacle scale of snakes and geckos

    NARCIS (Netherlands)

    Doorn, van K.; Sivak, J.G.

    2015-01-01

    The spectral transmittance of the optical media of the eye plays a substantial role in tuning the spectrum of light available for capture by the retina. Certain squamate reptiles, including snakes and most geckos, shield their eyes beneath a layer of transparent, cornified skin called the

  13. Controlled crumpling of graphene oxide films for tunable optical transmittance.

    Science.gov (United States)

    Thomas, Abhay V; Andow, Brandon C; Suresh, Shravan; Eksik, Osman; Yin, Jie; Dyson, Anna H; Koratkar, Nikhil

    2015-06-03

    The delamination buckling approach provides a facile means to dynamically control the optical transmittance of extremely flexible and stretchable graphene oxide coatings with fast response time. Such graphene oxide coatings can be deposited by scalable solution-processing methods for potential applications in dynamic glazing. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. 47 CFR 97.313 - Transmitter power standards.

    Science.gov (United States)

    2010-10-01

    ....313 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES... must use the minimum transmitter power necessary to carry out the desired communications. (b) No... an effective radiated power (ERP) exceeding 50 W PEP on the 60 m band. For the purpose of computing...

  15. 47 CFR 95.855 - Transmitter effective radiated power limitation.

    Science.gov (United States)

    2010-10-01

    .... 95.855 Section 95.855 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND... Transmitter effective radiated power limitation. The effective radiated power (ERP) of each CTS and RTU shall be limited to the minimum necessary for successful communications. No CTS or fixed RTU may transmit...

  16. ALTERNATIVE METHOD FOR ON SITE EVALUATION OF THERMAL TRANSMITTANCE

    Directory of Open Access Journals (Sweden)

    Aleksandar Janković

    2017-08-01

    Full Text Available Thermal transmittance or U-value is an indicator of the building envelope thermal properties and a key parameter for evaluation of heat losses through the building elements due to heat transmission. It can be determined by calculation based on thermal characteristics of the building element layers. However, this value does not take into account the effects of irregularities and degradation of certain elements of the envelope caused by aging, which may lead to errors in calculation of the heat losses. An effective and simple method for determination of thermal transmittance is in situ measurement, which is governed by the ISO 9869-1:2014 that defines heat flow meter method. This relatively expensive method leaves marks and damages surface of the building element. Furthermore, the final result is not always reliable, in particular when the building element is light or when the weather conditions are not suitable. In order to avoid the above mentioned problems and to estimate the real thermal transmittance value an alternative experimental method, here referred as the natural convection and radiation method, is proposed in this paper. For determination of thermal transmittance, this method requires only temperatures of inside and outside air, as well as the inner wall surface temperature. A detailed statistical analysis, performed by the software package SPSS ver. 20, shows several more advantages of this method comparing to the standard heat flow meter one, besides economic and non-destructive benefits.

  17. A method for predicting the direct transmittance of atmospheric ...

    African Journals Online (AJOL)

    The trends in the variations of the two models are identical but the disparity in the magnitudes of the transmittances tends to widen with increasing value of air mass under the specified conditions, particularly for air masses 20. Appropriate reasons have been given for the observed differences. It is proposed that the ...

  18. Efficient and Compact Semiconductor Laser Transmitter Modules Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Develop a Compact Transmitter Module (CTM) capable of operating at 1.26 5m, 1.57 5m and at 2 5m complete with all drive and control electronics for the TEC and the...

  19. analysis of an analysis of an intelligent temperature transmitter

    African Journals Online (AJOL)

    eobe

    analog to digital converters working with the basic sensor circuit as the key propellants in the advancement of transmitter technology. Despite several .... which include constrains in energy supply, storage capacity and bandwidth not to ... sine wave of digital signals which make up 1.2 KHz and 2.2 KHz, representing bits 1 ...

  20. Surgical insertion of transmitters and telemetry methods in fisheries research

    DEFF Research Database (Denmark)

    Rub, A. Michelle Wargo; Jepsen, Niels; Liedtke, Theresa L.

    2014-01-01

    ) will be described. Effects of surgical insertion of transmitters (ie, tagging) and aspects of the surgical implantation process where collaboration and professional exchanges among nonveterinarian researchers and veterinarians may be most fruitful will be discussed. Although this report focuses on surgical...

  1. Optimisation of radio transmitter locations in mobile telecommunications networks

    Directory of Open Access Journals (Sweden)

    Schmidt-Dumont, Thorsten

    2016-08-01

    Full Text Available Multiple factors have to be taken into account when mobile telecommunication network providers make decisions about radio transmitter placement. Generally, area coverage and the average signal level provided are of prime importance in these decisions. These criteria give rise to a bi-objective problem of facility location, with the goal of achieving an acceptable trade-off between maximising the total area coverage and maximising the average signal level provided to the demand region by a network of radio transmitters. This paper establishes a mathematical modelling framework, based on these two placement criteria, for evaluating the effectiveness of a given set of radio transmitter locations. In the framework, coverage is measured according to the degree of obstruction of the so-called ‘Fresnel zone’ that is formed between handset and base station, while signal strength is modelled taking radio wave propagation loss into account. This framework is used to formulate a novel bi-objective facility location model that may form the basis for decision support aimed at identifying high-quality transmitter location trade-off solutions for mobile telecommunication network providers. But it may also find application in various other contexts (such as radar, watchtower, or surveillance camera placement optimisation.

  2. 22 CFR 181.7 - Transmittal to the Congress.

    Science.gov (United States)

    2010-04-01

    ... Assistant Legal Adviser for Treaty Affairs to the Senate Committee on Foreign Affairs. ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Transmittal to the Congress. 181.7 Section 181.7 Foreign Relations DEPARTMENT OF STATE INTERNATIONAL AGREEMENTS COORDINATION, REPORTING AND...

  3. 48 CFR 5.207 - Preparation and transmittal of synopses.

    Science.gov (United States)

    2010-10-01

    ... Preparation and transmittal of synopses. (a) Content. Each synopsis transmitted to the GPE must address the... of manufacture. (6) Quantity, including any options for additional quantities. (7) Unit of issue. (8...) If the technical data required to respond to the solicitation will not be furnished as part of such...

  4. Music-Evoked Emotions—Current Studies

    Directory of Open Access Journals (Sweden)

    Hans-Eckhardt Schaefer

    2017-11-01

    Full Text Available The present study is focused on a review of the current state of investigating music-evoked emotions experimentally, theoretically and with respect to their therapeutic potentials. After a concise historical overview and a schematic of the hearing mechanisms, experimental studies on music listeners and on music performers are discussed, starting with the presentation of characteristic musical stimuli and the basic features of tomographic imaging of emotional activation in the brain, such as functional magnetic resonance imaging (fMRI and positron emission tomography (PET, which offer high spatial resolution in the millimeter range. The progress in correlating activation imaging in the brain to the psychological understanding of music-evoked emotion is demonstrated and some prospects for future research are outlined. Research in psychoneuroendocrinology and molecular markers is reviewed in the context of music-evoked emotions and the results indicate that the research in this area should be intensified. An assessment of studies involving measuring techniques with high temporal resolution down to the 10 ms range, as, e.g., electroencephalography (EEG, event-related brain potentials (ERP, magnetoencephalography (MEG, skin conductance response (SCR, finger temperature, and goose bump development (piloerection can yield information on the dynamics and kinetics of emotion. Genetic investigations reviewed suggest the heredity transmission of a predilection for music. Theoretical approaches to musical emotion are directed to a unified model for experimental neurological evidence and aesthetic judgment. Finally, the reports on musical therapy are briefly outlined. The study concludes with an outlook on emerging technologies and future research fields.

  5. Music-Evoked Emotions—Current Studies

    Science.gov (United States)

    Schaefer, Hans-Eckhardt

    2017-01-01

    The present study is focused on a review of the current state of investigating music-evoked emotions experimentally, theoretically and with respect to their therapeutic potentials. After a concise historical overview and a schematic of the hearing mechanisms, experimental studies on music listeners and on music performers are discussed, starting with the presentation of characteristic musical stimuli and the basic features of tomographic imaging of emotional activation in the brain, such as functional magnetic resonance imaging (fMRI) and positron emission tomography (PET), which offer high spatial resolution in the millimeter range. The progress in correlating activation imaging in the brain to the psychological understanding of music-evoked emotion is demonstrated and some prospects for future research are outlined. Research in psychoneuroendocrinology and molecular markers is reviewed in the context of music-evoked emotions and the results indicate that the research in this area should be intensified. An assessment of studies involving measuring techniques with high temporal resolution down to the 10 ms range, as, e.g., electroencephalography (EEG), event-related brain potentials (ERP), magnetoencephalography (MEG), skin conductance response (SCR), finger temperature, and goose bump development (piloerection) can yield information on the dynamics and kinetics of emotion. Genetic investigations reviewed suggest the heredity transmission of a predilection for music. Theoretical approaches to musical emotion are directed to a unified model for experimental neurological evidence and aesthetic judgment. Finally, the reports on musical therapy are briefly outlined. The study concludes with an outlook on emerging technologies and future research fields. PMID:29225563

  6. Do ambient urban odors evoke basic emotions?

    Directory of Open Access Journals (Sweden)

    Sandra Theresia Weber-Glass

    2014-04-01

    Full Text Available Fragrances, such as plant odors, have been shown to evoke autonomic response patterns associated with Ekman’s (Ekman et al., 1983 basic emotions happiness, surprise, anger, fear, sadness and disgust. Inducing positive emotions by odors in highly frequented public spaces could serve to improve the quality of life in urban environments. Thus, the present study evaluated the potency of ambient odors connoted with an urban environment to evoke basic emotions on an autonomic and cognitive response level. Synthetic mixtures representing the odors of disinfectant, candles / bees wax, summer air, burnt smell, vomit and musty smell as well as odorless water as a control were presented five times in random order to 30 healthy, non-smoking human subjects with intact sense of smell. Skin temperature, skin conductance, breathing rate, forearm muscle activity, blink rate and heart rate were recorded simultaneously. Subjects rated the odors in terms of pleasantness, intensity and familiarity and gave verbal labels to each odor as well as cognitive associations with the basic emotions. The results showed that the amplitude of the skin conductance response varied as a function of odor presentation. Burnt smell and vomit elicited significantly higher electrodermal responses than summer air. Also, a negative correlation was revealed between the amplitude of the skin conductance response and hedonic odor valence indicating that the magnitude of the electrodermal response increased with odor unpleasantness. The analysis of the cognitive associations between odors and basic emotions showed that candles / bees wax and summer air were specifically associated with happiness whereas burnt smell and vomit were uniquely associated with disgust. Our findings suggest that city odors may evoke specific cognitive associations of basic emotions and that autonomic activity elicited by such odors is related to odor hedonics.

  7. Somatosensory evoked response: application in neurology

    Directory of Open Access Journals (Sweden)

    Carlos A. M. Guerreiro

    1982-03-01

    Full Text Available One technique used for short-latency somatosensory evoked response (SER is described. SER following nerve stimulation is a unique non-invasive, clinical test used to evaluate the somatosensory pathways. It tests the physiological function of the median nerve, the brachial plexus, the C6-7 cervical roots, cervical spinal cord, the cuneate nuclei, the medial lemniscus, the thalamus, and the contralateral sensory cortex. It has been shown to be a reliable and useful clinical test partiicularly in multiple sclerosis and comatose patients. The promising technique of SER following peroneal nerve stimulation is mentioned.

  8. Sensory-Evoked Intrinsic Imaging Signals in the Olfactory Bulb Are Independent of Neurovascular Coupling

    Directory of Open Access Journals (Sweden)

    Roberto Vincis

    2015-07-01

    Full Text Available Functional brain-imaging techniques used in humans and animals, such as functional MRI and intrinsic optical signal (IOS imaging, are thought to largely rely on neurovascular coupling and hemodynamic responses. Here, taking advantage of the well-described micro-architecture of the mouse olfactory bulb, we dissected the nature of odor-evoked IOSs. Using in vivo pharmacology in transgenic mouse lines reporting activity in different cell types, we show that parenchymal IOSs are largely independent of neurotransmitter release and neurovascular coupling. Furthermore, our results suggest that odor-evoked parenchymal IOSs originate from changes in light scattering of olfactory sensory neuron axons, mostly due to water movement following action potential propagation. Our study sheds light on a direct correlate of neuronal activity, which may be used for large-scale functional brain imaging.

  9. Evoked potentials in pediatric cerebral malaria

    Directory of Open Access Journals (Sweden)

    Minal Bhanushali

    2011-08-01

    Full Text Available Cortical evoked potentials (EP provide localized data regarding brain function and may offer prognostic information and insights into the pathologic mechanisms of malariamediated cerebral injury. As part of a prospective cohort study, we obtained somatosensory evoked potentials (SSEPs and brainstem auditory EPs (AEPs within 24 hours of admission on 27 consecutive children admitted with cerebral malaria (CM. Children underwent follow-up for 12 months to determine if they had any long term neurologic sequelae. EPs were obtained in 27 pediatric CM admissions. Two children died. Among survivors followed an average of 514 days, 7/25 (28.0% had at least one adverse neurologic outcome. Only a single subject had absent cortical EPs on admission and this child had a good neurologic outcome. Among pediatric CM survivors, cortical EPs are generally intact and do not predict adverse neurologic outcomes. Further study is needed to determine if alterations in cortical EPs can be used to predict a fatal outcome in CM.

  10. [Personality dimensions and cerebral evoked potential].

    Science.gov (United States)

    Camposano, S; Alvarez, C; Lolas, F

    1994-12-01

    Eysenck's personality theory postulates 3 orthogonal dimensions of personality: extraversion (E), neuroticism (N) and psychoticism (P), predicting conductual and physiological predispositions to suffer mental illness. Biological bases of Eysenck's personality traits have been documented electrophysiologically. Psychoticism, the latest described dimension, is controverted, since there is some evidence of common factors with the other two. In order to assess the relation between Eysenck's dimensions and sensorial reactivity and information encoding processes we studied 20 healthy young subjects (mean age 28.5 years) with flash visual cortical evoked potentials (VEP, 3 intensities, peak to peak amplitude of III, IV-V-VI, VII components), and auditory cognitive evoked potentials (odd ball paradigm, P300 latency). There was a positive correlation between N and P dimensions (Spearman, r = 0.52), between N and VEP amplitude at high intensity (r = 0.58) and a negative correlation between E and P300 latency (r = 0.58). In short we found that P is not an independent dimension, but is related to sensorial reactivity. E dimension was related to encoding processes supporting Eysenck's observations about memory and learning differences.

  11. Long Latency Auditory Evoked Potentials during Meditation.

    Science.gov (United States)

    Telles, Shirley; Deepeshwar, Singh; Naveen, Kalkuni Visweswaraiah; Pailoor, Subramanya

    2015-10-01

    The auditory sensory pathway has been studied in meditators, using midlatency and short latency auditory evoked potentials. The present study evaluated long latency auditory evoked potentials (LLAEPs) during meditation. Sixty male participants, aged between 18 and 31 years (group mean±SD, 20.5±3.8 years), were assessed in 4 mental states based on descriptions in the traditional texts. They were (a) random thinking, (b) nonmeditative focusing, (c) meditative focusing, and (d) meditation. The order of the sessions was randomly assigned. The LLAEP components studied were P1 (40-60 ms), N1 (75-115 ms), P2 (120-180 ms), and N2 (180-280 ms). For each component, the peak amplitude and peak latency were measured from the prestimulus baseline. There was significant decrease in the peak latency of the P2 component during and after meditation (Pmeditation facilitates the processing of information in the auditory association cortex, whereas the number of neurons recruited was smaller in random thinking and non-meditative focused thinking, at the level of the secondary auditory cortex, auditory association cortex and anterior cingulate cortex. © EEG and Clinical Neuroscience Society (ECNS) 2014.

  12. New perspectives on vestibular evoked myogenic potentials.

    Science.gov (United States)

    Rosengren, Sally M; Kingma, Herman

    2013-02-01

    Although the vestibular evoked myogenic potential (VEMP) measured from the cervical muscles (cVEMP, cervical VEMP) is well described and has documented clinical utility, its analogue recorded from the extraocular muscles (oVEMP, ocular VEMP) has been described only recently and is currently emerging as an additional test of otolith function. This review will, therefore, summarize recent developments in VEMP research with a focus on the oVEMP. Recent studies suggest that the oVEMP is produced by otolith afferents in the superior vestibular nerve division, whereas the cVEMP evoked by sound is thought to be an inferior vestibular nerve reflex. Correspondingly, the oVEMP correlates better with caloric and subjective visual vertical tests than sound-cVEMPs. cVEMPs are more complicated than often thought, as shown by the presence of crossed responses and conflicting results of recent vibration studies. Altered inner ear mechanics produced by the vestibular diseases superior semicircular canal dehiscence and Ménière's disease lead to changes in the preferred frequency of the oVEMP and cVEMP. The oVEMP provides complementary diagnostic information to the cVEMP and is likely to be a useful addition to the diagnostic test battery in neuro-otology.

  13. Speech Evoked Auditory Brainstem Response in Stuttering

    Directory of Open Access Journals (Sweden)

    Ali Akbar Tahaei

    2014-01-01

    Full Text Available Auditory processing deficits have been hypothesized as an underlying mechanism for stuttering. Previous studies have demonstrated abnormal responses in subjects with persistent developmental stuttering (PDS at the higher level of the central auditory system using speech stimuli. Recently, the potential usefulness of speech evoked auditory brainstem responses in central auditory processing disorders has been emphasized. The current study used the speech evoked ABR to investigate the hypothesis that subjects with PDS have specific auditory perceptual dysfunction. Objectives. To determine whether brainstem responses to speech stimuli differ between PDS subjects and normal fluent speakers. Methods. Twenty-five subjects with PDS participated in this study. The speech-ABRs were elicited by the 5-formant synthesized syllable/da/, with duration of 40 ms. Results. There were significant group differences for the onset and offset transient peaks. Subjects with PDS had longer latencies for the onset and offset peaks relative to the control group. Conclusions. Subjects with PDS showed a deficient neural timing in the early stages of the auditory pathway consistent with temporal processing deficits and their abnormal timing may underlie to their disfluency.

  14. New Treatments for Drug-Resistant Epilepsy that Target Presynaptic Transmitter Release

    Science.gov (United States)

    2015-07-01

    focal cortical dysplasia and TSC-cortical tubers . Epilepsia 2009; 50: 1409-1418. [68] Crevecoeur J, Kaminski RM, Rogister B, Foerch P, Vandenplas C...neurological disorder that affects over three million Americans of all ages; it is as common and takes as many lives as breast cancer. On a global scale

  15. New Treatments for Drug-Resistant Epilepsy that Target Presynaptic Transmitter Release

    Science.gov (United States)

    2015-07-01

    subcutaneously injected and animals were led to seize during 1 hour following published protocol [3] and motor seizures were terminated with one diazepam ...the High Capacity cDNA Reverse Transcription Kit (P/N: 4368814; Applied Biosystems, ABI, California, USA) for synthesis of single-stranded cDNA. The...cDNA synthesis was carried out by following manufacturer’s protocol using random primers for 1 μg of starting RNA. Each RT reaction contained 1000

  16. Advocating neuroimaging studies of transmitter release in human physical exercise challenges studies

    Directory of Open Access Journals (Sweden)

    Henning Boecker

    2010-09-01

    Full Text Available Henning Boecker1, Ahmed Othman1, Sarah Mueckter1, Lukas Scheef1, Max Pensel1, Marcel Daamen1, Jakob Jankowski1, HH Schild2, TR Tölle3, M Schreckenberger41FE Klinische Funktionelle Neurobildgebung, Radiologische Universitätsklinik, Friedrich-Wilhelms–Universität Bonn, Germany; 2Radiologische Universitätsklinik, Friedrich-Wilhelms-Universität Bonn, Germany; 3TUM Neurologische Klinik und Poliklinik im Neuro-Kopf-Zentrum, Klinikum rechts der Isar der Technischen Universität München, München, Germany; 4Klinik und Poliklinik für Nuklearmedizin am Mainzer Universitätsklinikum, Johannes Gutenberg-Universität, Mainz, GermanyAbstract: This perspective attempts to outline the emerging role of positron emission tomography (PET ligand activation studies in human exercise research. By focusing on the endorphinergic system and its acclaimed role for exercise-induced antinociception and mood enhancement, we like to emphasize the unique potential of ligand PET applied to human athletes for uncovering the neurochemistry of exercise-induced psychophysiological phenomena. Compared with conventional approaches, in particular quantification of plasma beta-endorphin levels under exercise challenges, which are reviewed in this article, studying opioidergic effects directly in the central nervous system (CNS with PET and relating opioidergic binding changes to neuropsychological assessments, provides a more refined and promising experimental strategy. Although a vast literature dating back to the 1980s of the last century has been able to reproducibly demonstrate peripheral increases of beta-endorphin levels after various exercise challenges, so far, these studies have failed to establish robust links between peripheral beta-endorphin levels and centrally mediated behavioral effects, ie, modulation of mood and/or pain perception. As the quantitative relation between endorphins in the peripheral blood and the CNS remains unknown, the question arises, to what extent conventional blood-based methods can inform researchers about central neurotransmitter effects. As previous studies using receptor blocking approaches have also revealed equivocal results regarding exercise effects on pain and mood processing, it is expected that PET and other functional neuroimaging applications in athletes may in future help uncover some of the hitherto unknown links between neurotransmission and psychophysiological effects related to physical exercise.Keywords: positron emission tomography, beta-endorphins, opioids

  17. Advocating neuroimaging studies of transmitter release in human physical exercise challenges studies

    OpenAIRE

    Boecker, Henning

    2010-01-01

    Henning Boecker1, Ahmed Othman1, Sarah Mueckter1, Lukas Scheef1, Max Pensel1, Marcel Daamen1, Jakob Jankowski1, HH Schild2, TR Tölle3, M Schreckenberger41FE Klinische Funktionelle Neurobildgebung, Radiologische Universitätsklinik, Friedrich-Wilhelms–Universität Bonn, Germany; 2Radiologische Universitätsklinik, Friedrich-Wilhelms-Universität Bonn, Germany; 3TUM Neurologische Klinik und Poliklinik im Neuro-Kopf-Zentrum, Klinikum rechts der ...

  18. Advocating neuroimaging studies of transmitter release in human physical exercise challenges studies.

    Science.gov (United States)

    Boecker, Henning; Othman, Ahmed; Mueckter, Sarah; Scheef, Lukas; Pensel, Max; Daamen, Marcel; Jankowski, Jakob; Schild, Hh; Tölle, Tr; Schreckenberger, M

    2010-01-01

    This perspective attempts to outline the emerging role of positron emission tomography (PET) ligand activation studies in human exercise research. By focusing on the endorphinergic system and its acclaimed role for exercise-induced antinociception and mood enhancement, we like to emphasize the unique potential of ligand PET applied to human athletes for uncovering the neurochemistry of exercise-induced psychophysiological phenomena. Compared with conventional approaches, in particular quantification of plasma beta-endorphin levels under exercise challenges, which are reviewed in this article, studying opioidergic effects directly in the central nervous system (CNS) with PET and relating opioidergic binding changes to neuropsychological assessments, provides a more refined and promising experimental strategy. Although a vast literature dating back to the 1980s of the last century has been able to reproducibly demonstrate peripheral increases of beta-endorphin levels after various exercise challenges, so far, these studies have failed to establish robust links between peripheral beta-endorphin levels and centrally mediated behavioral effects, ie, modulation of mood and/or pain perception. As the quantitative relation between endorphins in the peripheral blood and the CNS remains unknown, the question arises, to what extent conventional blood-based methods can inform researchers about central neurotransmitter effects. As previous studies using receptor blocking approaches have also revealed equivocal results regarding exercise effects on pain and mood processing, it is expected that PET and other functional neuroimaging applications in athletes may in future help uncover some of the hitherto unknown links between neurotransmission and psychophysiological effects related to physical exercise.

  19. Do intracoelomic telemetry transmitters alter the post-release behaviour of migratory fish?

    Science.gov (United States)

    Wilson, Alexander D.M.; Hayden, Todd A.; Vandergoot, Christopher S.; Kraus, Richard T.; Dettmers, John M.; Cooke, Steven J.; Charles C. Krueger,

    2016-01-01

    Electronic tags have become a common tool in fish research, enhancing our understanding of how fish interact with their environment and move among different habitats, for estimating mortality and recording internal physiological states. An often-untested assumption of electronic tagging studies is that tagged fish are representative of untagged conspecifics and thus show ‘normal’ behaviour (e.g. movement rates, swimming activity, feeding). Here, we use a unique data set for potamadromous walleye (Sander vitreus) in Lake Huron and Lake Erie tributaries to assess whether the lack of appropriate controls in electronic tagging could seriously affect behavioural data. We used fish tagged in previous years and compared their migratory behaviour during the spawning season to fish tagged in a current year at the same location. The objective of the study was to determine whether intracoelomic acoustic tag implantation altered downstream movement of walleye after spawning. Fish tagged in a given season travelled slower downstream from two river spawning sites than fish tagged in previous years. Fish tagged one or two years earlier showed no differences between each other in downstream travel time, in contrast to fish tagged in a given year. Our results support notions that standard collection and intracoelomic tagging procedures can alter short-term behaviour (i.e. days, weeks, months), and as such, researchers should use caution when interpreting data collected over such time periods. Further, whenever possible, researchers should also explicitly evaluate post-tagging effects on behaviour as part of their experimental objectives.

  20. Intraurethral stimulation evokes bladder responses via 2 distinct reflex pathways.

    Science.gov (United States)

    Woock, John P; Yoo, Paul B; Grill, Warren M

    2009-07-01

    Recent animal studies have shown that selective activation of pudendal nerve branches can evoke bladder responses through 2 distinct reflex pathways. We examined intraurethral electrical stimulation as a minimally invasive means of selectively activating these pathways in the cat. Bladder responses evoked by intraurethral electrical stimulation were measured in alpha-chloralose anesthetized male cats at different stimulation frequencies, stimulation intensities and intraurethral locations. Intraurethral electrical stimulation evoked inhibitory and excitatory bladder reflexes depending on stimulation frequency and location. Stimulation in the penile urethra 0 to 3 cm from the urethral meatus at 33 Hz evoked bladder contraction and at 10 Hz it evoked bladder relaxation. These responses were abolished after bilateral transection of the dorsal penile nerves. Stimulation in the membranous urethra 5 to 7 cm from the urethral meatus at 2, 10 and 33 Hz evoked bladder contractions. These responses were abolished after bilateral transection of the cranial sensory nerves. Following acute spinal cord transection bladder contractions were still evoked by 33 Hz stimulation in the penile urethra but not by stimulation at any frequency in the membranous urethra. Intraurethral electrical stimulation selectively evoked bladder responses by activating 2 distinct pudendal afferent pathways. Responses depended on stimulation frequency and location. Intraurethral electrical stimulation is a valid means of determining the pathways involved in bladder responses evoked by pudendal nerve stimulation.

  1. 77 FR 28668 - Technical Standard Order (TSO)-C91a, Emergency Locator Transmitters (ELTs)

    Science.gov (United States)

    2012-05-15

    ... Technical Standard Order (TSO)-C91a, Emergency Locator Transmitter (ELT) Equipment. SUMMARY: This notice announces the FAA's cancellation of TSO-C91a, Emergency Locator Transmitter (ELT) Equipment. The effect of... December 1, 2012, must seek authorization for TSO-C126a, 406 MHz Emergency Locator Transmitter (ELT), or...

  2. Effects of radio transmitters on the behavior of Red-headed Woodpeckers

    Science.gov (United States)

    Mark Vukovich; John C. Kilgo

    2009-01-01

    Previous studies have revealed that radio-transmitters may affect bird behaviors, including feeding rates, foraging behavior, vigilance, and preening behavior. In addition, depending on the method of attachment, transmitters can potentially affect the ability of cavity-nesting birds to use cavities. Our objective was to evaluate effects of transmitters on the behavior...

  3. High-transmittance all-dielectric Huygens' metasurfaces (presentation video)

    Science.gov (United States)

    Staude, Isabelle; Decker, Manuel; Falkner, Matthias; Dominguez, Jason; Neshev, Dragomir N.; Brener, Igal; Pertsch, Thomas; Kivshar, Yuri S.

    2014-09-01

    We demonstrate a metamaterial Huygens' surfaces for near-infrared frequencies using high-permittivity all-dielectric nanoparticles with tailored Mie-type resonances as meta-atoms. We experimentally measure 360 degrees phase variation of the transmitted light in combination with high transmittance values for light passing through a fabricated metasurface exhibiting spectrally overlapping electric and magnetic dipole-type modes in the near-infrared spectral range. Our experimental measurements are in excellent agreement with numerical simulations and analytical calculations. High transmittance in combination with the simultaneously observed complete phase coverage is key for the realization of a wide range of applications including efficient wavefront shaping, dispersion control devices, and holograms.

  4. LOT-G3: Plasma Lamp, Ozonator and CW transmitter

    CERN Document Server

    Gobato, Ricardo; Gobato, Alekssander

    2015-01-01

    The LOT-G3 is designed to be a versatile equipment that perform several simple experiments for use in helping the physics classes for high school. Easy construction, low cost, using easily accessible materials. Its construction involves simple practices and knowledge of electromagnetism. It has the function of a plasma globe to demonstrate the ionization of a low pressure gas, as well as the formation of magnetic field. Can be used as sanitizer closed environments such as automotive vehicles in ozonator function, demonstrating the ionization of oxygen in the atmosphere, producing ozone, essential to life on earth. And as a sparks transmitter, low power, low frequency modulated continuous wave in (CW), for signals in Morse code. Therefore the equipment here called LOT-G3, has three functions: a plasma lamp, ozonator and CW transmitter.

  5. Cylindrical PVDF film transmitters and receivers for air ultrasound.

    Science.gov (United States)

    Toda, Minoru

    2002-05-01

    Cylindrical polyvinylidene fluoride (PVDF) film transducers for transmission and reception of 40-kHz ultrasonic waves in air have been investigated. A key feature of such transducers is their omni-directional polar response. An optimized structure comprises a cylindrical PVDF film element resting on a spool without a mechanical bond to it. Various key design equations to obtain the required ultrasonic performance both as transmitter and receiver are shown, which include resonance frequency, acoustic pressure, angle performance, back air cavity effect, and receiver sensitivity. Measurements of actual frequency response of transmitter output and receiver sensitivity, angular performance, back air space effect, and temperature effect are presented. The results agree well with the theoretical predictions. It has been shown that this device is well-suited for practical application as an ultrasonic ranging device.

  6. System for Isolation Testing of RF Transmitters and Receivers

    Science.gov (United States)

    2012-08-03

    memory 30B. [0018] Programmable device 30 can be based on a software defined radio ( SDR ) configured to operate as described herein. By way of example...one such software defined radio is the open source GNU radio platform utilizing the Universal Software Radio Peripheral. [0019] The advantages of...to a system that can perform isolation testing of a radio frequency (RF) transmitter or an RF receiver. (2) Description of the Prior Art [0004

  7. Laser Transmitters for the optical link systems used in CMS

    CERN Multimedia

    Maximilien Brice

    2005-01-01

    In the CMS experiment of the now new flagship LHC optical links will be used for the tracker readout system. One part of this components will be semiconductor laser (~50.000 !!!), named correctly: 1310 nm InGaAsP (DCPBH-MQW) edge-emitting laser. They are foreseen as transmitter in the Tx Hybrid part of the optical link system.

  8. Secure Broadcasting with Imperfect Channel State Information at the Transmitter

    KAUST Repository

    Hyadi, Amal

    2015-11-13

    We investigate the problem of secure broadcasting over fast fading channels with imperfect main channel state information (CSI) at the transmitter. In particular, we analyze the effect of the noisy estimation of the main CSI on the throughput of a broadcast channel where the transmission is intended for multiple legitimate receivers in the presence of an eavesdropper. Besides, we consider the realistic case where the transmitter is only aware of the statistics of the eavesdropper’s CSI and not of its channel’s realizations. First, we discuss the common message transmission case where the source broadcasts the same information to all the receivers, and we provide an upper and a lower bounds on the ergodic secrecy capacity. For this case, we show that the secrecy rate is limited by the legitimate receiver having, on average, the worst main channel link and we prove that a non-zero secrecy rate can still be achieved even when the CSI at the transmitter is noisy. Then, we look at the independent messages case where the transmitter broadcasts multiple messages to the receivers, and each intended user is interested in an independent message. For this case, we present an expression for the achievable secrecy sum-rate and an upper bound on the secrecy sum-capacity and we show that, in the limit of large number of legitimate receivers K, our achievable secrecy sum-rate follows the scaling law log((1−) log(K)), where is the estimation error variance of the main CSI. The special cases of high SNR, perfect and no-main CSI are also analyzed. Analytical derivations and numerical results are presented to illustrate the obtained expressions for the case of independent and identically distributed Rayleigh fading channels.

  9. Temperature Dependence of Light Transmittance in Polymer Dispersed Liquid Crystals

    OpenAIRE

    Bloisi, F.; Ruocchio, C.; Vicari, L

    1997-01-01

    Polymer Dispersed Liquid Crystals (PDLC) axe composite materials made of a dispersion of liquid crystal droplets in a polymeric matrix. When the liquid crystal is in the nematic phase, droplets appeax as optically anisotropic spheres and the material is opaque white. Sample transmittance is a function of the temperature. If the liquid crystal refractive index in the isotropic phase is equal to the one of the polymer, after the nematic-isotropic transition the material is transparent. We prese...

  10. Effects of satellite transmitters on captive and wild mallards

    Science.gov (United States)

    Kesler, Dylan C.; Raedeke, Andrew H.; Foggia, Jennifer R.; Beatty, William S.; Webb, Elisabeth B.; Humburg, Dale D.; Naylor, Luke W.

    2014-01-01

    Satellite telemetry has become a leading method for studying large-scale movements and survival in birds, yet few have addressed potential effects of the larger and heavier tracking equipment on study subjects. We simultaneously evaluated effects of satellite telemetry equipment on captive and wild mallards (Anas platyrhynchos) to assess impacts on behavior, body mass, and movement. We randomly assigned 55 captive ducks to one of 3 treatment groups, including a standard body harness group, a modified harness group, and a control group. Ducks in the control group were not fitted with equipment, whereas individuals in the other 2 groups were fitted with dummy transmitters attached with a Teflon ribbon harness or with a similar harness constructed of nylon cord. At the conclusion of the 14-week captive study, mean body mass of birds in the control group was 40–105 g (95% CI) greater than birds with standard harnesses, and 28–99 g (95% CI) greater than birds with modified harnesses. Further, results of focal behavior observations indicated ducks with transmitters were less likely to be in water than control birds. We also tested whether movements of wild birds marked with a similar Teflon harness satellite transmitter aligned with population movements reported by on-the-ground observers who indexed local abundances of mid-continent mallards throughout the non-breeding period. Results indicated birds marked with satellite transmitters moved concurrently with the larger unmarked population. Our results have broad implications for field research and suggest that investigators should consider potential for physiological and behavioral effects brought about by tracking equipment. Nonetheless, results from wild ducks indicate satellite telemetry has the potential to provide useful movement data.

  11. Resting Heart Rate and Auditory Evoked Potential

    Directory of Open Access Journals (Sweden)

    Simone Fiuza Regaçone

    2015-01-01

    Full Text Available The objective of this study was to evaluate the association between rest heart rate (HR and the components of the auditory evoked-related potentials (ERPs at rest in women. We investigated 21 healthy female university students between 18 and 24 years old. We performed complete audiological evaluation and measurement of heart rate for 10 minutes at rest (heart rate monitor Polar RS800CX and performed ERPs analysis (discrepancy in frequency and duration. There was a moderate negative correlation of the N1 and P3a with rest HR and a strong positive correlation of the P2 and N2 components with rest HR. Larger components of the ERP are associated with higher rest HR.

  12. Visual evoked potentials in rubber factory workers.

    Science.gov (United States)

    Tandon, O P; Kumar, V

    1997-01-01

    Pattern reversal visual evoked potentials (pVEP) were studied in 39 male rubber factory workers in the age range of 18-55 years and 20 control subjects (aged 18-46 years) not exposed to the rubber factory environment. Results revealed that 20 (51%) rubber factory workers had abnormal latencies of wave P1 (dominant component of pVEP) as per accepted criteria of 99% tolerance limit set for the control group (i.e. any value above mean +3 SD of control was considered abnormal). The section-wise per cent distribution of abnormalities was vulcanization (83%), tubing (75%), calendering (60%), loading (38%) and mixing (14%). This study provides electrophysiological evidence that rubber factory environments affect the conduction processes in optical pathways from their origin in the retina to striate cortex. However, this study has its limitations in not identifying the specific chemical(s) causing these changes in VEP.

  13. Bayesian analysis of MEG visual evoked responses

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, D.M.; George, J.S.; Wood, C.C.

    1999-04-01

    The authors developed a method for analyzing neural electromagnetic data that allows probabilistic inferences to be drawn about regions of activation. The method involves the generation of a large number of possible solutions which both fir the data and prior expectations about the nature of probable solutions made explicit by a Bayesian formalism. In addition, they have introduced a model for the current distributions that produce MEG and (EEG) data that allows extended regions of activity, and can easily incorporate prior information such as anatomical constraints from MRI. To evaluate the feasibility and utility of the Bayesian approach with actual data, they analyzed MEG data from a visual evoked response experiment. They compared Bayesian analyses of MEG responses to visual stimuli in the left and right visual fields, in order to examine the sensitivity of the method to detect known features of human visual cortex organization. They also examined the changing pattern of cortical activation as a function of time.

  14. Music evokes vicarious emotions in listeners

    Science.gov (United States)

    Kawakami, Ai; Furukawa, Kiyoshi; Okanoya, Kazuo

    2014-01-01

    Why do we listen to sad music? We seek to answer this question using a psychological approach. It is possible to distinguish perceived emotions from those that are experienced. Therefore, we hypothesized that, although sad music is perceived as sad, listeners actually feel (experience) pleasant emotions concurrent with sadness. This hypothesis was supported, which led us to question whether sadness in the context of art is truly an unpleasant emotion. While experiencing sadness may be unpleasant, it may also be somewhat pleasant when experienced in the context of art, for example, when listening to sad music. We consider musically evoked emotion vicarious, as we are not threatened when we experience it, in the way that we can be during the course of experiencing emotion in daily life. When we listen to sad music, we experience vicarious sadness. In this review, we propose two sides to sadness by suggesting vicarious emotion. PMID:24910621

  15. Fast Turn-off Mine Transient Electromagnetic Transmitter System

    Directory of Open Access Journals (Sweden)

    ZHENG Xiao-Liang

    2014-05-01

    Full Text Available For solving problems such as short turn-off time, high linear degree of falling edge, measurement of turn-off time and influence of primary signals for transient electromagnetic transmitter, and restrictions because of the environmental conditions of underground coal mine, this thesis aims at designing a new transient electromagnetic transmitter system suitable for coal mine. Supported by damping absorption circuit, such system applies small volume, sectional transmitting coil, with features of short turn-off time, high linear degree of current falling edge. It uses the transmitter monitoring circuit, which accurately measures turn-off time and simultaneously records the current value changes after turn-off, thus to eliminate the influence of primary field as well as to restore earlier secondary field signals for reference and finally to improve the ability to detect the shallow structure. It turns out that the new system has a shorter turn-off time, a higher linear degree of current falling and more accurate data record of turn-off current.

  16. RECORDING OF VESTIBULAR EVOKED MYOGENIC POTENTIALS

    Directory of Open Access Journals (Sweden)

    A. A. Sazgar

    2006-05-01

    Full Text Available It has been shown recently that loud clicks evoke myogenic potentials in the tonically contracting sternocleidomastoid muscles. Studies have suggested that these potentials are of vestibular origin, especially of the saccule and inferior vestibular nerve. A pilot study was undertaken in our hospital to record vestibular evoked myogenic potentials (VEMP for the first time in Iran. Eighteen healthy volunteers (32 ears without history of otologic or vestibular disorders were subjected to the VEMP test. Twenty-one patients (26 ears with unilateral (6 patients and bilateral (5 patients high frequency sensorineural hearing loss with unknown etiology, acoustic neuroma (1 patient, Meniere’s disease (4 patients and unilateral low frequency sensorineural hearing loss without vestibular complaint (5 patients were also enrolled in this study. VEMP response to clicks was obtained from 84.4% of ears of healthy subjects. These subjects demonstrated short latency waves to click stimuli during tonic neck flexor activation. Mean latencies of first positive (p13 and first negative (n23 potentials in healthy subjects were 12.45 ± 1.9 ms and 20.8 ± 3.5 ms, respectively. Median latencies of these two potentials were 12.1 and 19.3 ms, respectively. We could record VEMP in 5 patients with unilateral and all patients with high and low frequency sensorineural hearing loss without vestibular complaint. In the patient with acoustic neuroma VEMP was absent on the affected side. This technique may offer a new method to evaluate otolith and sacculocollic pathways in human.

  17. Hyposmolarity evokes norepinephrine efflux from synaptosomes by a depolarization- and Ca2+ -dependent exocytotic mechanism.

    Science.gov (United States)

    Tuz, K; Pasantes-Morales, H

    2005-10-01

    Osmolarity reduction (20%) elicited 3H-norepinephrine (NE) efflux from rat cortical synaptosomes. The hyposmotic NE release resulted from the following events: (i) a Na+-dependent and La3+-, Gd3+- and ruthenium red-sensitive depolarization; (ii) a cytosolic Ca2+ ([Ca2+]i) rise with contributions from external Ca2+ influx and internal Ca2+ release, probably through the mitochondrial Na+-Ca2+ exchanger; and (iii) activation of a [Ca2+]i-evoked, tetanus toxin (TeTX)-sensitive, PKC-modulated NE efflux mechanism. This sequence was established from results showing a drop in the hyposmotic [Ca2+]i rise by preventing depolarization with La3+, and by the inhibitory effects of Ca2+-free medium (EGTA; 50%), CGP37157 (the mitochondrial Na+-Ca2+ exchanger blocker; 48%), EGTA + CGP37157 or by EGTA-AM (> 95% in both cases). In close correspondence with these effects, NE efflux was 92% decreased by Na+ omission, 75% by La3+, 47% by EGTA, 50% by CGP37157, 90% by EGTA + CGP37157 and 88% by EGTA-AM. PKC influenced the intracellular Ca2+ release and, mainly through this action, modulated NE efflux. TeTX suppressed NE efflux. The K+-stimulated NE release, studied in parallel, was unaffected by Na+ omission, or by La3+, Gd3+ or ruthenium red. It was fully dependent on external Ca2+, insensitive to CGP37157 and abolished by TeTX. These results suggest that the hyposmotic events, although different from the K+-evoked depolarization and [Ca2+]i rise mechanisms, are able to trigger a depolarization-dependent, Ca2+-dependent and TeTX-sensitive mechanism for neurotransmitter release.

  18. Sex differences in pudendal somatosensory evoked potentials.

    Science.gov (United States)

    Pelliccioni, G; Piloni, V; Sabbatini, D; Fioravanti, P; Scarpino, O

    2014-06-01

    Somatosensory evoked potentials (SEPs) of the pudendal nerve are a well-established diagnostic tool for the evaluation of pelvic floor disorders. However, the possible influence of sex differences on response latencies has not been established yet. The aim of this study was to standardize the procedures and to evaluate possible effects of gender differences on anal and penile/clitoral SEPs. The anal and dorsal penile/clitoral SEPs were recorded in 84 healthy subjects (40 males and 44 females; mean age 47.9 ± 16.6 years, range 16-81 years; mean height 168.3 ± 20.3 cm, range 155-187 cm). Pudendal SEPs were evoked with a bipolar surface electrode stimulating the clitoris or the base of the penis and the anal orifice and recorded using scalp electrodes. The latency of the first positive component (P1) was measured. The effect and possible interaction of (a) stimulation site and (b) gender on the two variables was explored by multivariate analysis of variance (MANOVA). The examination was well tolerated and a reproducible waveform of sufficient quality was obtained in all the subjects examined. In the female subjects, a mean cortical P1 latency of 37.0 ± 2.6 and 36.4 ± 3.2 ms for anal and clitoral stimulation, respectively, was found. In the male subjects, the cortical latencies were 38.0 ± 3.5 ms for the anal stimulation and 40.2 ± 3.7 ms for the penile stimulation. At MANOVA, a statistically significant main effect of stimulation site and gender as well as a significant interaction between the two variables was found. Anal and dorsal penile/clitoral SEPs represent a well-tolerated and reproducible method to assess the functional integrity of the sensory pathways in male and female subjects. Obtaining sex-specific reference data, by individual electrophysiological testing, is highly recommended because of significant latency differences between males and females, at least as far as penile/clitoral responses are concerned.

  19. Assessment of Barotrauma Resulting from Rapid Decompression of Depth Acclimated Juvenile Chinook Salmon Bearing Radio Telemetry Transmitters

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Richard S.; Carlson, Thomas J.; Welch, Abigail E.; Stephenson, John R.; Abernethy, Cary S.; McKinstry, Craig A.; Theriault, Marie-Helene

    2007-09-06

    A multifactor study was conducted by Battelle for the US Army Corps of Engineers to assess the significance of the presence of a radio telemetry transmitter on the effects of rapid decompression from simulated hydro turbine passage on depth acclimated juvenile run-of-the-river Chinook salmon. Study factors were: (1) juvenile chinook salmon age;, subyearling or yearling, (2) radio transmitter present or absent, (3) three transmitter implantation factors: gastric, surgical, and no transmitter, and (4) four acclimation depth factors: 1, 10, 20, and 40 foot submergence equivalent absolute pressure, for a total of 48 unique treatments. Exposed fish were examined for changes in behavior, presence or absence of barotrauma injuries, and immediate or delayed mortality. Logistic models were used to test hypotheses that addressed study objectives. The presence of a radio transmitter was found to significantly increase the risk of barotrauma injury and mortality at exposure to rapid decompression. Gastric implantation was found to present a higher risk than surgical implantation. Fish were exposed within 48 hours of transmitter implantation so surgical incisions were not completely healed. The difference in results obtained for gastric and surgical implantation methods may be the result of study design and the results may have been different if tested fish had completely healed surgical wounds. However, the test did simulate the typical surgical-release time frame for in-river telemetry studies of fish survival so the results are probably representative for fish passing through a turbine shortly following release into the river. The finding of a significant difference in response to rapid decompression between fish bearing radio transmitters and those not implies a bias may exist in estimates of turbine passage survival obtained using radio telemetry. However, the rapid decompression (simulated turbine passage) conditions used for the study represented near worst case exposure

  20. Retention and effects of miniature transmitters in juvenile American eels

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, Robert P.; Janak, Jill; Liss, Stephanie A.; Brown, Richard S.; Deng, Zhiqun; Harnish, Ryan A.

    2017-11-01

    This study was conducted to assess the effects of a non-functional acoustic micro transmitter (tag) on survival, tag loss, and swimming ability of juvenile American eels (Anguilla rostrata). The transmitter was designed for implantation through a < 3 mm opening into the body cavity of anguilliform fishes without the need for sutures. American eels used for the swimming performance study were 113–175 mm (N = 120). There were two treatment groups (tagged and non-tagged), each treatment was split into six size groups of 10 mm for testing. Potential transmitter effects on swimming performance were examined by comparing critical swimming speeds (Ucrit an index of prolonged swimming performance) for tagged and non-tagged eels. There was no significant difference in Ucrit between tagged and non-tagged eels for all of the size groups tested. Median Ucrits for tagged eels ranged from 50.2 cm/s for the smallest group tested (113–119 mm) to 63.9 cm/s for fish 141–150 mm in length. Non-tagged group median Ucrits ranged from 47.2 cm/s for the smallest group to 66.9 cm/s for the 141–150 mm group. An additional 26 eels (115–208 mm) were tagged and held for 38 d (without undergoing swimming performance tests) to determine the effects on survival and tag loss. There was no mortality during the holding period and the majority of the tag loss occurred after 20 days post-tagging, which is the current projected life of the tag. Our results indicate that micro acoustic tags can be successfully implanted in juvenile American eels with no apparent impacts to swimming ability, and would be a viable option for examining eel movement patterns in river systems and near hydroelectric facilities.

  1. Visually evoked spiking evolves while spontaneous ongoing dynamics persist

    Directory of Open Access Journals (Sweden)

    Raoul eHuys

    2016-01-01

    Full Text Available Neurons in the primary visual cortex spontaneously spike even when there are no visual stimuli. It is unknown whether the spiking evoked by visual stimuli is just a modification of the spontaneous ongoing cortical spiking dynamics or whether the spontaneous spiking state disappears and is replaced by evoked spiking. This study of laminar recordings of spontaneous spiking and visually evoked spiking of neurons in the ferret primary visual cortex shows that the spiking dynamics does not change: the spontaneous spiking as well as evoked spiking is controlled by a stable and persisting fixed point attractor. Its existence guarantees that evoked spiking return to the spontaneous state. However, the spontaneous ongoing spiking state and the visual evoked spiking states are qualitatively different and are separated by a threshold (separatrix. The functional advantage of this organization is that it avoids the need for a system reorganization following visual stimulation, and impedes the transition of spontaneous spiking to evoked spiking and the propagation of spontaneous spiking from layer 4 to layers 2-3.

  2. Evoked otoacoustic emissions behaviour in retinitis pigmentosa.

    Science.gov (United States)

    Fiore, C; Cagini, C; Menduno, P; Toniassoni, I; Desantis, A; Pennacchi, A; Ricci, G; Molini, E

    1994-01-01

    The hearing function was studied in 26 patients affected by retinitis pigmentosa (RP) and in their relatives. Sixteen patients showed bilateral normal hearing when examined with traditional audiometric methods. In these normoacusic patients evoked otoacoustic emissions (EOE) have been studied. The EOE offer a unique opportunity to measure objectively the function of outer hair cells: they record the amplitude of the energy produced by the outer hair cells of the coclea following an acoustic stimulation. The data have been statistically compared, using the Student's t-test, with those obtained in a homogeneous control-group of normal subjects. In normoacusic subjects with RP the average values of EOE intensity are statistically lower than those of normal subjects in 64 of the 127 frequency bands examined. Moreover, the distribution of the EOE in patients with retinitis pigmentosa proved to be more discontinous than that observed in the normal subjects. The EOE recorded in 14 normoacusic relatives show in some cases small anomalies but the data, on account of the limited sample group, cannot be statistically evaluated. Therefore a subclinical alteration of the Organ of Corti is found in 100% of the patients affected by RP, although they appear to be normoacusic to usual audiometric tests.

  3. Transient evoked otoacoustic emissions in rock musicians.

    Science.gov (United States)

    Høydal, Erik Harry; Lein Størmer, Carl Christian; Laukli, Einar; Stenklev, Niels Christian

    2017-09-01

    Our focus in this study was the assessment of transient evoked otoacoustic emissions (TEOAEs) in a large group of rock musicians. A further objective was to analyse tinnitus among rock musicians as related to TEOAEs. The study was a cross-sectional survey of rock musicians selected at random. A control group was included at random for comparison. We recruited 111 musicians and a control group of 40 non-musicians. Testing was conducted by using clinical examination, pure tone audiometry, TEOAEs and a questionnaire. TEOAE SNR in the half-octave frequency band centred on 4 kHz was significantly lower bilaterally in musicians than controls. This effect was strongly predicted by age and pure-tone hearing threshold levels in the 3-6 kHz range. Bilateral hearing thresholds were significantly higher at 6 kHz in musicians. Twenty percent of the musicians had permanent tinnitus. There was no association between the TEOAE parameters and permanent tinnitus. Our results suggest an incipient hearing loss at 6 kHz in rock musicians. Loss of TEOAE SNR in the 4 kHz half-octave frequency band was observed, but it was related to higher mean 3-6 kHz hearing thresholds and age. A large proportion of rock musicians have permanent tinnitus.

  4. Visual evoked potential study in slow learners.

    Science.gov (United States)

    Khaliq, Farah; Anjana, Yumnam; Vaney, Neelam

    2009-01-01

    Slow learners are individuals with low achievement and comparably low IQ scores. It may be a symptom reflecting a larger underlying problem in them. Sensory neural processing of visual information can be one of the contributory factors for their underachievement. The present study was undertaken to examine the integrity and function of visual pathway by means of Visual Evoked Potential (VEP). Pattern reversal VEP was performed on seventeen slow learners. Fifteen age and sex matched children with good school performance and normal IQ were taken as controls. There was significant prolongation of N75 component of VEP in slow learners. The latencies of P100 and N145 were also increased but could not reach the level of significance. Our findings are suggestive of the presence of a weaker VEP response in slow learners indicative of a deficit early in the visual processing. There is some abnormality in the geniculate afferents to V1 which is consistent with a defect in the magnocellular pathway at the level of Visual Area 1 or earlier.

  5. Behavioral modelling and predistortion of wideband wireless transmitters

    CERN Document Server

    Ghannouchi, Fadhel M; Helaoui, Mohamed

    2015-01-01

    Covers theoretical and practical aspects related to the behavioral modelling and predistortion of wireless transmitters and power amplifiers. It includes simulation software that enables the users to apply the theory presented in the book. In the first section, the reader is given the general background of nonlinear dynamic systems along with their behavioral modelling from all its aspects. In the second part, a comprehensive compilation of behavioral models formulations and structures is provided including memory polynomial based models, box oriented models such as Hammerstein-based and Wiene

  6. Atmospheric transmittance and radiance - The LOWTRAN 5 code

    Science.gov (United States)

    Kneizys, F. X.; Shettle, E. P.; Gallery, W. O.

    1981-01-01

    A computer code, LOWTRAN 5, has been developed for calculating the transmission and background radiance of the earth's atmosphere at moderate spectral resolution 20 per cm. The code was derived using a single parameter band model for molecular absorption and includes the effects of continuum absorption, molecular scattering, and aerosol extinction. A choice of atmospheric models and aerosol models is provided to the user for any atmospheric slant path. The LOWTRAN model is described and application of the code is given by examples of atmospheric transmittance and radiance spectra. Comments on the validity of the code are presented.

  7. Cost-effective tunable 1310nm DWDM transmitter

    Science.gov (United States)

    Chorchos, Łukasz; Turkiewicz, Jarosław P.

    2015-09-01

    The growing demand for higher data rate transmissions in local and metropolitan area networks is main reason of developing effective and inexpensive transmission systems. In this paper, study about the possibility to realize 1310 nm tunable DWDM transmitter using commercially available low-cost DFB lasers is presented. Extensive DFB lasers characterization has been performed which led to establish relationships between laser current, operational temperature, emitted wavelength and power. An algorithm to find the laser settings for a desired wavelength grid has been proposed and tested. Generation of the 1310nm DWDM channels with frequency spacing between 120 and 240GHz has been demonstrated.

  8. Effects of ethanol on neurotransmitter release and intracellular free calcium in PC12 cells

    Energy Technology Data Exchange (ETDEWEB)

    Rabe, C.S.; Weight, F.F.

    1988-02-01

    The effect of ethanol on muscarine-stimulated release of l-(/sup 3/H)norepinephrine ((/sup 3/H)NE) was studied using the rat pheochromocytoma cell line, PC12. At concentrations of 25 mM and above, ethanol produced a dose-dependent inhibition of muscarine-stimulated release of (/sup 3/H)NE. The inhibition of muscarine-stimulated transmitter release occurred in the absence of any detectable effect of ethanol on (/sup 3/H)NE uptake or on muscarinic binding to the cells. However, ethanol produced an inhibition of muscarine-stimulated elevation of intracellular free Ca++ which corresponded with the inhibition of transmitter release. At concentrations greater than 100 mM, ethanol produced an increase in the basal release of (/sup 3/H)NE. Intracellular free Ca++ also was increased by ethanol concentrations greater than 100 mM. The elevation of basal transmitter release and intracellular free Ca++ by concentrations of ethanol greater than 100 mM occurred independently of the inhibition by ethanol of muscarine-stimulated elevation of intracellular free Ca++ and transmitter secretion. These results suggest that the effects of ethanol on neurotransmitter release are associated with the effects of ethanol on intracellular free Ca++.

  9. Suomi NPP VIIRS solar diffuser screen transmittance model and its applications.

    Science.gov (United States)

    Lei, Ning; Xiong, Xiaoxiong; Mcintire, Jeff

    2017-11-01

    The visible infrared imaging radiometer suite on the Suomi National Polar-orbiting Partnership satellite calibrates its reflective solar bands through observations of a sunlit solar diffuser (SD) panel. Sunlight passes through a perforated plate, referred to as the SD screen, before reaching the SD. It is critical to know whether the SD screen transmittance measured prelaunch is accurate. Several factors such as misalignments of the SD panel and the measurement apparatus could lead to errors in the measured transmittance and thus adversely impact on-orbit calibration quality through the SD. We develop a mathematical model to describe the transmittance as a function of the angles that incident light makes with the SD screen, and apply the model to fit the prelaunch measured transmittance. The results reveal that the model does not reproduce the measured transmittance unless the size of the apertures in the SD screen is quite different from the design value. We attribute the difference to the orientation alignment errors for the SD panel and the measurement apparatus. We model the alignment errors and apply our transmittance model to fit the prelaunch transmittance to retrieve the "true" transmittance. To use this model correctly, we also examine the finite source size effect on the transmittance. Furthermore, we compare the product of the retrieved "true" transmittance and the prelaunch SD bidirectional reflectance distribution function (BRDF) value to the value derived from on-orbit data to determine whether the prelaunch SD BRDF value is relatively accurate. The model is significant in that it can evaluate whether the SD screen transmittance measured prelaunch is accurate and help retrieve the true transmittance from the transmittance with measurement errors, consequently resulting in a more accurate sensor data product by the same amount.

  10. Reliability of the Achilles tendon tap reflex evoked during stance using a pendulum hammer.

    Science.gov (United States)

    Mildren, Robyn L; Zaback, Martin; Adkin, Allan L; Frank, James S; Bent, Leah R

    2016-01-01

    The tendon tap reflex (T-reflex) is often evoked in relaxed muscles to assess spinal reflex circuitry. Factors contributing to reflex excitability are modulated to accommodate specific postural demands. Thus, there is a need to be able to assess this reflex in a state where spinal reflex circuitry is engaged in maintaining posture. The aim of this study was to determine whether a pendulum hammer could provide controlled stimuli to the Achilles tendon and evoke reliable muscle responses during normal stance. A second aim was to establish appropriate stimulus parameters for experimental use. Fifteen healthy young adults stood on a forceplate while taps were applied to the Achilles tendon under conditions in which postural sway was constrained (by providing centre of pressure feedback) or unconstrained (no feedback) from an invariant release angle (50°). Twelve participants repeated this testing approximately six months later. Within one experimental session, tap force and T-reflex amplitude were found to be reliable regardless of whether postural sway was constrained (tap force ICC=0.982; T-reflex ICC=0.979) or unconstrained (tap force ICC=0.968; T-reflex ICC=0.964). T-reflex amplitude was also reliable between experimental sessions (constrained ICC=0.894; unconstrained ICC=0.890). When a T-reflex recruitment curve was constructed, optimal mid-range responses were observed using a 50° release angle. These results demonstrate that reliable Achilles T-reflexes can be evoked in standing participants without the need to constrain posture. The pendulum hammer provides a simple method to allow researchers and clinicians to gather information about reflex circuitry in a state where it is involved in postural control. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Evoked potentials and head injury. 1. Rating of evoked potential abnormality.

    Science.gov (United States)

    Rappaport, M; Hall, K; Hopkins, H K; Belleza, T

    1981-10-01

    This paper describes a method for rating the degree of abnormality of auditory, visual and somatosensory evoked potential patterns in head injury (HI) patients. Criteria for judging degree of EP abnormality are presented that allow assessment of the extent and severity of subcortical and cortical dysfunction associated with traumatic brain damage. Interrater reliability data based upon blind ratings of normal and HI patients are presented and shown to be highly significant. Tables of normative values of peak latencies and amplitudes are given and illustrations of EP patterns of different degrees of abnormality are presented.

  12. D2-dopamine receptor-mediated inhibition of intracellular Ca2+ mobilization and release of acetylcholine from guinea-pig neostriatal slices.

    Science.gov (United States)

    Fujiwara, H; Kato, N; Shuntoh, H; Tanaka, C

    1987-06-01

    The effect of dopamine receptor activation on electrically- or high K+ (30 mM)-evoked neurotransmitter release and rise in intracellular Ca2+ concentration was investigated using slices of guinea-pig neostriatum. A specific D2-dopamine receptor agonist, LY-171555 (a laevorotatory enantiomer of LY-141865: N-propyl tricyclic pyrazole) at 10(-6) M inhibited electrical stimulation- and high K+-evoked release of [3H]-acetylcholine ([3H]-ACh) to 47.7 +/- 6.0% and 54.1 +/- 5.0% of control, respectively. The maximal inhibition by LY-171555 at 10(-5) M was 54.8 +/- 5.1% reduction of the control. The half-maximal effective concentration (EC50) of LY-171555 for the inhibition of [3H]-ACh release was 2.3 X 10(-7) M. A specific D2-dopamine receptor antagonist, (-)-sulpiride (10(-7) M) reversed the inhibition of [3H]-ACh release induced by LY-171555. A specific D1-dopamine receptor agonist, SK&F 38393 (2,3,4,5-tetrahydro-7,8-dihydroxy-1-phenyl-1H-benzazepine) (10(-5) M) had no effect on the release of [3H]-ACh. LY-171555 (10(-6) M) also inhibited the high K+-evoked endogenous glutamate release, by 47% of control. This inhibitory effect was reversed by (-)-sulpiride (10(-7) M). We used a fluorescent, highly selective Ca2+ indicator, 'quin 2' to measure intracellular free Ca2+ concentrations ([Ca2+]i). Electrical stimulation of slices preloaded with quin 2 led to an elevation of relative fluorescence intensity and this response was reduced by the removal of Ca2+ from the bathing medium. These results indicate that the enhanced elevation in fluorescence intensity in the quin 2-loaded slices reflects the increase of intracellular free Ca2+ concentration, [Ca2+]i. The mixed D1- and D2-receptor agonist, apomorphine and LY-171555 inhibited the increase of [Ca2+]i induced by electrical stimulation or high K+ medium, in a concentration-dependent manner, while SK&F 38393 did not affect the increase of [Ca2+]i. The maximal inhibitory effect of LY-171555 at 3 X 10(-5) M was 35 +/- 3

  13. [Glu2]TRH dose-dependently attenuates TRH-evoked analeptic effect in the mouse brain

    Science.gov (United States)

    Nguyen, Vien; Zharikova, Alevtina D.; Prokai-Tatrai, Katalin; Prokai, Laszlo

    2010-01-01

    Thyrotropin-releasing hormone (TRH, pGlu-His-Pro-NH2) and the structurally related [Glu2]TRH (pGlu-Glu-Pro-NH2) are endogenous peptides with a plethora of actions in the central nervous system. Many centrally-mediated effects of TRH are shared with those of [Glu2]TRH, although the involvement of different receptors are presumed. The analeptic action is the best-known TRH-related central nervous system effect. While [Glu2]TRH itself is analeptic, its co-administration with TRH into mice produced a dose-depended attenuation of TRH-evoked reversal of barbiturate-induced sleeping time. This finding is in agreement with our previous observations that [Glu2]TRH significantly attenuates TRH-induced hippocampal extracellular acetylcholine release. Taken together, [Glu2]TRH may be considered as a negative modulator for the cholinergic effect of TRH in the mouse brain. PMID:20188155

  14. [Glu2]TRH dose-dependently attenuates TRH-evoked analeptic effect in mice.

    Science.gov (United States)

    Nguyen, Vien; Zharikova, Alevtina D; Prokai-Tatrai, Katalin; Prokai, Laszlo

    2010-04-29

    Thyrotropin-releasing hormone (TRH, pGlu-His-Pro-NH(2)) and the structurally related [Glu(2)]TRH (pGlu-Glu-Pro-NH(2)) are endogenous peptides with a plethora of actions in the central nervous system. Many centrally-mediated effects of TRH are shared with those of [Glu(2)]TRH, although the involvement of different receptors is presumed. The analeptic action is the best-known TRH-related central nervous system effect. While [Glu(2)]TRH itself is analeptic, its co-administration with TRH into mice produced a dose-dependent attenuation of TRH-evoked reversal of barbiturate-induced sleeping time. This finding is in agreement with our previous observations that [Glu(2)]TRH significantly attenuates TRH-induced hippocampal extracellular acetylcholine release. Taken together, [Glu(2)]TRH may be considered as a negative modulator for the cholinergic effect of TRH in the mouse brain. Copyright 2010 Elsevier Inc. All rights reserved.

  15. Involvement of multiple calcium channels in neurotransmitter release from cultured sympathetic neurons

    Energy Technology Data Exchange (ETDEWEB)

    Hirning, L.D.; Perney, T.M.; Miller, R.J.

    1986-03-01

    The release of neurotransmitters has been defined to be a Ca/sup + +/ dependent process, however, the role of Ca/sup + +/ channels in the release process is unclear. Primary cultures of sympathetic nerves from superior cervical ganglia were used to examine the specific actions of dihydropyridine (DHP) drugs. In nerve cultures, /sup 3/H-norepinepharine (NE) was taken up in a desipramine blockable fashion and released on exposure to high external K/sup +/ concentrations. NE release was virtually abolished by Co/sup + +/ (3 mM) or in Ca/sup + +/ free media, demonstrating the Ca/sup + +/ dependence of the release. However, the antagonist DHP, nimodipine, was ineffective in blocking transmitter release in concentrations up to 10/sup -5/M. In contrast, the agonist DHP, Bay K8644 (10/sup -6/M), significantly enhanced transmitter release by 35-40% of control. This enhancement was blocked down to control levels by nimodipine (10/sup -6/M). The authors have also demonstrated high affinity /sup 3/H-nitrendipine binding sites (B/sub max/ = 179 fmoles/mg, Kd = 0.25 nM) on these sympathetic neuronal membranes. These data suggest that DHP sensitive Ca/sup + +/ channels, which have been shown to modulate SP release from DRG neurons in culture are not usually involved in NE release from sympathetic neurons. However, prolonged opening of these channels by the DHP agonist, Bay K8644, increases the overall Ca/sup + +/ influx into sympathetic nerves to enhance transmitter release.

  16. Thermal transmittance of a cellulose loose-fill insulation material

    Energy Technology Data Exchange (ETDEWEB)

    Nicolajsen, A. [Danish Building and Urban Research, Hoersholm (Denmark). Department of Building Technology and Productivity

    2005-07-15

    The thermal performance of cellulose insulation material was investigated and compared with the thermal performance of stone wool batts. The moisture content in selected facade elements insulated with cellulose loose-fill insulation material and stone wool, was investigated as well as the influence of the moisture content on thermal transmittance. The investigation was carried out as a full-scale test under normal climate conditions in a moisture test house facility. Facade elements were built as timber frame constructions. Heat flow through the facade elements was measured with built-in heat flowmeters and the moisture content in the thermal insulation behind the wind barrier was measured with moisture measuring dowels. The test showed that the thermal performance of the tested type of cellulose loose-fill insulation material was significantly lower than the thermal performance of stone wool batts. The maximum moisture content of the insulation material was below, what in Denmark is considered critical for the onset of rot and growth of wood decaying fungi. The thermal transmittance did not change with changes in the moisture content within the investigated hygroscopic range. (author)

  17. Modified Polar Sigma-Delta Transmitter for Multiradio Applications

    Directory of Open Access Journals (Sweden)

    Maršálek Roman

    2010-01-01

    Full Text Available Radio transmitters capable of transforming variable envelope signals into constant envelope signals can be associated with high-efficiency switched mode power amplifiers. One of the techniques providing this conversion is Polar Sigma-Delta ( architecture. This approach provides efficient solution for high-dynamic signals, and, moreover, it offers flexibility in a multiradio environment. The overall concept of the polar transmitter is presented here along with novel modifications and improvements. Namely, when recombining the envelope and the phase signals, it is suggested to replace the analog mixing by a digital mixing. The impact of a frequency synthesizer with a switched loop bandwidth and its imperfections on the overall polar architecture is investigated as well. The Mobile WiMAX standard has been chosen for validation due to very high requirements in terms of power dynamics and the variable channel bandwidth. Simulation results are presented in this paper, and advantages and drawbacks of this novel approach are pointed here as well.

  18. Assessment of the calibration curve for transmittance pulse-oximetry

    Science.gov (United States)

    Doronin, A.; Fine, I.; Meglinski, I.

    2011-11-01

    Optical/laser modalities provide a broad variety of practical solutions for clinical diagnostics and therapy in a range from imaging of single cells and molecules to non-invasive biopsy of specific biological tissues and organs tomography. Near-infrared transmittance pulse oximetry with laser diodes is the accepted standard in current clinical practice and widely used for noninvasive monitoring of oxygen saturation in arterial blood hemoglobin. Conceptual design of practical pulse oximetry systems requires careful selection of various technical parameters, including intensity, wavelength, beam size and profile of incident laser radiation, size, numerical aperture of the detector, as well as a clear understanding of how the spatial and temporal structural alterations in biological tissues can be linked with and can be distinguished by variations of these parameters. In current letter utilizing state-of-the-art NVIDEA CUDA technology, a new object oriented programming paradigm and on-line solutions we introduce a computational tool applied for human finger transmittance spectra simulation and assessment of calibration curve for near-infrared transmitted pulseoximetry.

  19. Towards a neural basis of music-evoked emotions.

    Science.gov (United States)

    Koelsch, Stefan

    2010-03-01

    Music is capable of evoking exceptionally strong emotions and of reliably affecting the mood of individuals. Functional neuroimaging and lesion studies show that music-evoked emotions can modulate activity in virtually all limbic and paralimbic brain structures. These structures are crucially involved in the initiation, generation, detection, maintenance, regulation and termination of emotions that have survival value for the individual and the species. Therefore, at least some music-evoked emotions involve the very core of evolutionarily adaptive neuroaffective mechanisms. Because dysfunctions in these structures are related to emotional disorders, a better understanding of music-evoked emotions and their neural correlates can lead to a more systematic and effective use of music in therapy. Copyright 2010 Elsevier Ltd. All rights reserved.

  20. Distraction Reduces Both Early and Late Electrocutaneous Stimulus Evoked Potentials

    NARCIS (Netherlands)

    Blom, J.H.G.; Wiering, Caro H.; van der Lubbe, Robert Henricus Johannes

    2012-01-01

    Previous electroencephalography studies revealed mixed effects of sustained distraction on early negative and later positive event-related potential components evoked by electrocutaneous stimuli. In our study we further examined the influence of sustained distraction to clarify these discrepancies.

  1. Click-evoked responses in vestibular afferents in rats

    National Research Council Canada - National Science Library

    Zhu, Hong; Tang, Xuehui; Wei, Wei; Mustain, William; Xu, Youguo; Zhou, Wu

    2011-01-01

    Sound activates not only the cochlea but also the vestibular end organs. Research on this phenomenon led to the discovery of the sound-evoked vestibular myogenic potentials recorded from the sternocleidomastoid muscles...

  2. Renin release

    DEFF Research Database (Denmark)

    Schweda, Frank; Friis, Ulla; Wagner, Charlotte

    2007-01-01

    The aspartyl-protease renin is the key regulator of the renin-angiotensin-aldosterone system, which is critically involved in salt, volume, and blood pressure homeostasis of the body. Renin is mainly produced and released into circulation by the so-called juxtaglomerular epithelioid cells, located...

  3. The effect of ketamine on intraspinal acetylcholine release

    DEFF Research Database (Denmark)

    Abelson, Klas S P; Goldkuhl, Renée Röstlinger; Nylund, Anders

    2006-01-01

    The general anaesthetic ketamine affects the central cholinergic system in several manners, but its effect on spinal acetylcholine release, which may be an important transmitter in spinal antinociception, is unknown. This study aimed to investigate the effect of ketamine on spinal acetylcholine...... increased the acetylcholine release in high concentrations (100 microM to 10 mM). The results indicate that spinal nicotinic receptors are important for the ketamine-induced acetylcholine release, and that the effect is partly mediated at the spinal level....

  4. Flash visual evoked potentials in preterm infants.

    Science.gov (United States)

    Feng, Jing-Jing; Wang, Wei-Ping; Guo, Shu-Juan; Liu, Zhi-Wei; Xu, Xiu

    2013-03-01

    To describe the development of flash visual evoked potentials (FVEPs) in preterm infants from 1 to 18 months and to determine if the maturation of FVEPs is similar to that of term infants. Longitudinal follow-up study. Twenty very low birth weight (VLBW) preterm infants, 42 low birth weight (LBW) preterm infants, and 41 term infants underwent FVEP recordings and neurodevelopmental examinations at 1, 3, 6, 9, 12, and 18 months of corrected and chronological ages. The FVEP recordings were carried out with the VikingQuest-IV neuroelectrophysiological device (VikingQuest, Nicolet, WI), and neurodevelopmental assessments were made by the Development Screen Test and Bayley Scales of Infant Development, Second Edition. At 1, 3, 6, and 9 months of age, neurodevelopment was measured with the Mental Index and Developmental Quotient. At 12 and 18 months, neurodevelopment was assessed using the Mental Developmental Index and Psychomotor Developmental Index. Two FVEP values were analyzed: the P2 amplitude (peak to peak from the preceding N2 wave) and the latency of the P2 wave. There was no significant difference for age-dependent decreased pattern of FVEP P2 latency between preterm infants and the control group. This pattern consisted of a rapid decrease in the first 6 months of life, a gradual decline from 6 to 12 months of age, and a steady reduction from 12 to 18 months of age. The P2 latencies were prolonged significantly at all 6 recorded times in the VLBW group compared with the controls and showed a delay in the LBW group at 1 and 3 months of corrected age. The maturation of P2 latency in LBW infants is similar to that of the controls at 3 months of corrected age, but the maturation of P2 latency in VLBW children remained delayed when compared with the controls until 18 months of corrected age. Although the FVEP development pattern of preterm infants was similar to that of healthy full-term infants, the former had deficits in visual electrophysiologic maturation

  5. Leaf Relative Water Content Estimated from Leaf Reflectance and Transmittance

    Science.gov (United States)

    Vanderbilt, Vern; Daughtry, Craig; Dahlgren, Robert

    2016-01-01

    Remotely sensing the water status of plants and the water content of canopies remain long term goals of remote sensing research. In the research we report here, we used optical polarization techniques to monitor the light reflected from the leaf interior, R, as well as the leaf transmittance, T, as the relative water content (RWC) of corn (Zea mays) leaves decreased. Our results show that R and T both change nonlinearly. The result show that the nonlinearities cancel in the ratio R/T, which appears linearly related to RWC for RWC less than 90%. The results suggest that potentially leaf water status and perhaps even canopy water status could be monitored starting from leaf and canopy optical measurements.

  6. Design Parameters of a Miniaturized Piezoelectric Underwater Acoustic Transmitter

    Directory of Open Access Journals (Sweden)

    Thomas J. Carlson

    2012-07-01

    Full Text Available PZT ceramics have been widely used in underwater acoustic transducers. However, literature available discussing the design parameters of a miniaturized PZT-based low-duty-cycle transmitter is very limited. This paper discusses some of the design parameters—the backing material, driving voltage, PZT material type, power consumption and the transducer length of a miniaturized acoustic fish tag using a PZT tube. Four different types of PZT were evaluated with respect to the source level, energy consumption and bandwidth of the transducer. The effect of the tube length on the source level is discussed. The results demonstrate that ultralow-density closed-cell foam is the best backing material for the PZT tube. The Navy Type VI PZTs provide the best source level with relatively low energy consumption and that a low transducer capacitance is preferred for high efficiency. A 35% reduction in the transducer length results in 2 dB decrease in source level.

  7. High power optical transmitter package for free space optical communication

    Science.gov (United States)

    Hildebrand, U.; Menke, B.; Wiesmann, Th.; Ohm, G.

    1990-07-01

    This paper discusses the characteristics of a new concept involving high-power laser diode (HPLD) arrays which are able to emit up to 1000 mW of optical output power but which suffer from poor far-field pattern and poor optical quality, related to the gain guiding mechanism used in such devices. Methods are proposed for improving the optical quality of HPLDs. These include the use of apertured AM scheme for HPLDs and the use of a graded-index lens and a stripe mirror to stabilize the HPLD. A HPLD optical transmitter is designed which will have the capability of operating the HPLD in the 180 deg phase alternating mode under modulation.

  8. Comparison between ASHRAE and ISO thermal transmittance calculation methods

    DEFF Research Database (Denmark)

    Blanusa, Petar; Goss, William P.; Roth, Hartwig

    2007-01-01

    the Heat Transfer and Total Optical Properties of Fenestration Products, Public Review Draft of Standard 142P, American Society of Heating, Refrigerating and Air Conditioning Engineers, Atlanta, 1998]) and in Europe [ISO 10077-2. Thermal Performance of Windows, Doors and Shutters-Calculation of Thermal...... Transmittance-Part 2: Numerical Method for Frames, International Standards Organization, Geneva, 2003]. The two approaches, called the ASHRAE and ISO methods, are different in the way they treat the effect of the glazing spacer on the heat transfer through the frame and the glazing unit near the frame....... The ASHRAE method assumes that the spacer effects both the heat transfer through the frame and the heat transfer through the glazing in an "edge-of glass" region 63.5mm (2.5in.) from the glazing/frame sight line. The ISO method assumes that the additional heat transfer due to the existence of the spacer...

  9. Electromagnetic Cavity Effects from Transmitters Inside a Launch Vehicle Fairing

    Science.gov (United States)

    Trout, Dawn H.; Wahid, Parveen F.; Stanley, James E.

    2009-01-01

    This paper provides insight into the difficult analytical issue for launch vehicles and spacecraft that has applicability outside of the launch industry. Radiation from spacecraft or launch vehicle antennas located within enclosures in the launch vehicle generates an electromagnetic environment that is difficult to accurately predict. This paper discusses the test results of power levels produced by a transmitter within a representative scaled vehicle fairing model and provides preliminary modeling results at the low end of the frequency test range using a commercial tool. Initially, the walls of the fairing are aluminum and later, layered with materials to simulate acoustic blanketing structures that are typical in payload fairings. The effects of these blanketing materials on the power levels within the fairing are examined.

  10. Effect of transmitter turn-off time on transient soundings

    Science.gov (United States)

    Fitterman, D.V.; Anderson, W.L.

    1987-01-01

    A general procedure for computing the effect of non-zero turn-off time on the transient electromagnetic response is presented which can be applied to forward and inverse calculation methods for any transmitter-receiver configuration. We consider in detail the case of a large transmitter loop which has a receiver coil located at the center of the loop (central induction or in-loop array). For a linear turn-off ramp of width t0, the voltage response is shown to be the voltage due to an ideal step turn-off averaged over windows of width t0. Thus the effect is similar to that obtained by using averaging windows in the receiver. In general when time zero is taken to be the end of the ramp, the apparent resistivity increases for a homogeneous half-space over a limited time range. For time zero taken to be the start of the ramp the apparent resistivity is affected in the opposite direction. The effect of the ramp increases with increasing t0 and first-layer resistivity, is largest during the intermediate stage, and decreases with increasing time. It is shown that for a ramp turn-off, there is no effect in the early and late stages. For two-layered models with a resistive first layer (??1>??2), the apparent resistivity is increased in the intermediate stage. When the first layer is more conductive than the second layer (??1geoelectrical section on the turn-off effect. Neglecting the turn-off ramp will affect data interpretation as shown by field examples; the influence is the greatest on near-surface layer parameters. ?? 1987.

  11. The paradox of music-evoked sadness: an online survey.

    Science.gov (United States)

    Taruffi, Liila; Koelsch, Stefan

    2014-01-01

    This study explores listeners' experience of music-evoked sadness. Sadness is typically assumed to be undesirable and is therefore usually avoided in everyday life. Yet the question remains: Why do people seek and appreciate sadness in music? We present findings from an online survey with both Western and Eastern participants (N = 772). The survey investigates the rewarding aspects of music-evoked sadness, as well as the relative contribution of listener characteristics and situational factors to the appreciation of sad music. The survey also examines the different principles through which sadness is evoked by music, and their interaction with personality traits. Results show 4 different rewards of music-evoked sadness: reward of imagination, emotion regulation, empathy, and no "real-life" implications. Moreover, appreciation of sad music follows a mood-congruent fashion and is greater among individuals with high empathy and low emotional stability. Surprisingly, nostalgia rather than sadness is the most frequent emotion evoked by sad music. Correspondingly, memory was rated as the most important principle through which sadness is evoked. Finally, the trait empathy contributes to the evocation of sadness via contagion, appraisal, and by engaging social functions. The present findings indicate that emotional responses to sad music are multifaceted, are modulated by empathy, and are linked with a multidimensional experience of pleasure. These results were corroborated by a follow-up survey on happy music, which indicated differences between the emotional experiences resulting from listening to sad versus happy music. This is the first comprehensive survey of music-evoked sadness, revealing that listening to sad music can lead to beneficial emotional effects such as regulation of negative emotion and mood as well as consolation. Such beneficial emotional effects constitute the prime motivations for engaging with sad music in everyday life.

  12. The paradox of music-evoked sadness: an online survey.

    Directory of Open Access Journals (Sweden)

    Liila Taruffi

    Full Text Available This study explores listeners' experience of music-evoked sadness. Sadness is typically assumed to be undesirable and is therefore usually avoided in everyday life. Yet the question remains: Why do people seek and appreciate sadness in music? We present findings from an online survey with both Western and Eastern participants (N = 772. The survey investigates the rewarding aspects of music-evoked sadness, as well as the relative contribution of listener characteristics and situational factors to the appreciation of sad music. The survey also examines the different principles through which sadness is evoked by music, and their interaction with personality traits. Results show 4 different rewards of music-evoked sadness: reward of imagination, emotion regulation, empathy, and no "real-life" implications. Moreover, appreciation of sad music follows a mood-congruent fashion and is greater among individuals with high empathy and low emotional stability. Surprisingly, nostalgia rather than sadness is the most frequent emotion evoked by sad music. Correspondingly, memory was rated as the most important principle through which sadness is evoked. Finally, the trait empathy contributes to the evocation of sadness via contagion, appraisal, and by engaging social functions. The present findings indicate that emotional responses to sad music are multifaceted, are modulated by empathy, and are linked with a multidimensional experience of pleasure. These results were corroborated by a follow-up survey on happy music, which indicated differences between the emotional experiences resulting from listening to sad versus happy music. This is the first comprehensive survey of music-evoked sadness, revealing that listening to sad music can lead to beneficial emotional effects such as regulation of negative emotion and mood as well as consolation. Such beneficial emotional effects constitute the prime motivations for engaging with sad music in everyday life.

  13. The Paradox of Music-Evoked Sadness: An Online Survey

    Science.gov (United States)

    Taruffi, Liila; Koelsch, Stefan

    2014-01-01

    This study explores listeners’ experience of music-evoked sadness. Sadness is typically assumed to be undesirable and is therefore usually avoided in everyday life. Yet the question remains: Why do people seek and appreciate sadness in music? We present findings from an online survey with both Western and Eastern participants (N = 772). The survey investigates the rewarding aspects of music-evoked sadness, as well as the relative contribution of listener characteristics and situational factors to the appreciation of sad music. The survey also examines the different principles through which sadness is evoked by music, and their interaction with personality traits. Results show 4 different rewards of music-evoked sadness: reward of imagination, emotion regulation, empathy, and no “real-life” implications. Moreover, appreciation of sad music follows a mood-congruent fashion and is greater among individuals with high empathy and low emotional stability. Surprisingly, nostalgia rather than sadness is the most frequent emotion evoked by sad music. Correspondingly, memory was rated as the most important principle through which sadness is evoked. Finally, the trait empathy contributes to the evocation of sadness via contagion, appraisal, and by engaging social functions. The present findings indicate that emotional responses to sad music are multifaceted, are modulated by empathy, and are linked with a multidimensional experience of pleasure. These results were corroborated by a follow-up survey on happy music, which indicated differences between the emotional experiences resulting from listening to sad versus happy music. This is the first comprehensive survey of music-evoked sadness, revealing that listening to sad music can lead to beneficial emotional effects such as regulation of negative emotion and mood as well as consolation. Such beneficial emotional effects constitute the prime motivations for engaging with sad music in everyday life. PMID:25330315

  14. Neurotransmitter release from tottering mice nerve terminals with reduced expression of mutated P- and Q-type Ca2+-channels.

    NARCIS (Netherlands)

    Leenders, A,G.; van den Maagdenberg, A.M.; Lopes da Silva, F.H.; Shen, Z.H.; Molenaar, P.C.M.; Ghijsen, W.E.J.M.

    2002-01-01

    Neurotransmitter release is triggered by Ca2+-influx through multiple sub-types of high voltage-activated Ca2+-channels. Tottering mice have a mutation in the alpha1A pore-forming subunit of P- and Q-type Ca2+-channels, two prominent sub-types that regulate transmitter release from central nerve

  15. Placement of intracoelomic radio transmitters and silicone passive sampling devices in northern leopard frogs (Lithobates pipiens)

    Science.gov (United States)

    Zaffarano, Bianca Anne; Yaw, Taylor; Swanson, Jennifer E; Pierce, Clay; Muths, Erin L.; Smalling, Kelly; Vandever, Mark

    2017-01-01

    Historically, wetland toxin exposure studies have relied on single time point samples from stationary sampling devices. Development of passive sampling devices (PSDs) that can be attached to individual animals within wetland habitats has greatly improved in recent years, presenting an innovative sampling technology that can potentially yield individual-specific, quantifiable data about chemical exposure. In this study, silicone based PSDs were attached to the ventral skin of 20 northern leopard frogs (Lithobates pipiens) with polypropylene sutures after radio transmitters had been surgically implanted into the coleomic cavity. After a recovery period frogs were released back into the wetland habitat where they were acquired. The animals were located daily using radio telemetry to assess how long PSDs would remain attached in the frogs' natural habitat. After one week, PSDs remained on 18 of the original 20 frogs. At 2 weeks 17 frogs were recovered and no PSDs remained attached. Although valuable data can be obtained over a short time period, more research will be necessary to demonstrate effectiveness of externally attaching silicone PSDs to northern leopard frogs for time periods longer than 1-2 weeks.

  16. Membrane permeable C-terminal dopamine transporter peptides attenuate amphetamine-evoked dopamine release

    DEFF Research Database (Denmark)

    Rickhag, Karl Mattias; Owens, WA; Winkler, Marie-Therese

    2013-01-01

    /Discs-large/ZO-1 (PDZ)-binding sequence of DAT, was made membrane-permeable by fusing it to the cell membrane transduction domain of the HIV-1 Tat protein (TAT-C24WT). The ability of TAT-C24WT but not a scrambled peptide (TAT-C24Scr) to block the CaMKIIα-DAT interaction was supported by co...

  17. Effect of package light transmittance on vitamin content of milk. Part 2: UHT whole milk

    NARCIS (Netherlands)

    Saffert, A.; Pieper, G.; Jetten, J.

    2008-01-01

    This work is the second part of a milk study evaluating the effect of package light transmittance on the vitamin content of milk, in this case on UHT whole milk. The milk was stored at three different light intensities in polyethylene terephthalate (PET) bottles with varying light transmittance as

  18. Integrated S-band transmitter with on-chip DC-DC converter and control loop

    NARCIS (Netherlands)

    Brouzes, H.; Geurts, S.; Besselink, M.; Telli, A.; Hek, A.P. de; Bent, G. van der; Vliet, F.E. van

    2012-01-01

    A highly integrated high-power transmitter has been designed in a high breakdown GaAs MMIC technology. The transmitter includes, on top of an S-Band 10 W class-F HPA, a DC/DC converter and its associated gate driver, the full voltage regulation control loop, which provides a significant step for

  19. 31 CFR 538.319 - U.S. registered money transmitter.

    Science.gov (United States)

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false U.S. registered money transmitter. 538.319 Section 538.319 Money and Finance: Treasury Regulations Relating to Money and Finance... General Definitions § 538.319 U.S. registered money transmitter. The term U.S. registered money...

  20. 31 CFR 537.323 - U.S. registered money transmitter.

    Science.gov (United States)

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false U.S. registered money transmitter. 537.323 Section 537.323 Money and Finance: Treasury Regulations Relating to Money and Finance... General Definitions § 537.323 U.S. registered money transmitter. The term U.S. registered money...

  1. A 100 – 800MHz 8-Path polyphase transmitter with mixer duty-cycle control achieving

    NARCIS (Netherlands)

    Subhan, S.; Klumperink, Eric A.M.; Ghaffari, A.; Wienk, Gerhardus J.M.; Nauta, Bram

    2014-01-01

    Radio transceivers capable of dynamic spectrum access require frequency agile transmitters with a clean output spectrum. High-Q filters are difficult to implement on chip and have limited tuning range. Transmitters with high linearity and broadband harmonic rejection can be more flexible and require

  2. 47 CFR 2.813 - Transmitters operated in the Instructional Television Fixed Service.

    Science.gov (United States)

    2010-10-01

    ... Television Fixed Service. 2.813 Section 2.813 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL... Devices § 2.813 Transmitters operated in the Instructional Television Fixed Service. Section 2.803 (a) through (d) shall not be applicable to a transmitter operated in the Instructional Television Fixed...

  3. Influence of Distance Between Metal Squares in Checkerboard Patterns on Transmittance Characteristics in the Infrared Region

    Science.gov (United States)

    Higashira, Takaya; Kageyama, Tomoaki; Kashiwagi, Kouhei; Miyashita, Hidetoshi; Takano, Keisuke; Nakajima, Makoto; Lee, Sang-Seok

    2017-09-01

    In this study, we investigated the influence of the distance between metal squares in self-complementary metal checkerboard patterns (CPs) on the transmittance characteristics in the infrared (IR) region. Transmittance characteristics of CPs in the IR region are rarely studied. Here, to clarify experimentally the influence of reactance variation in CPs on the transmittance in the IR region, we fabricated self-complementary metallic CPs with differing distances between the metal squares, and their transmittances were measured. Initially, two types of capacitive CPs (C-CPs) and three types of inductive CPs (I-CPs) were fabricated, and their IR transmittances were measured. The CPs were configured to have different gaps or overlapping distances between the metal squares for the C-CPs and I-CPs, respectively. Furthermore, we investigated the influence of the distance configuration of CPs consisting of both C-CPs and I-CPs, on the transmittances of x- and y-polarized incident IR electromagnetic waves. The evaluated hybrid CPs, referred to as anisotropic CPs (A-CPs), were fabricated with horizontal metal patterns in contact with each other and separated vertical components. The results demonstrated that the transmittance depends on sensitively to the gap or the overlapping distance between the metal squares of the self-complementary metallic CPs. Moreover, we observed remarkable changes in the transmittance associated with the A-CPs, resulting from the polarization of the incident IR electromagnetic waves.

  4. Negative control in two-component signal transduction by transmitter phosphatase activity

    Science.gov (United States)

    Huynh, TuAnh Ngoc; Stewart, Valley

    2011-01-01

    Bifunctional sensor transmitter modules of two-component systems exert both positive and negative control on the receiver domain of the cognate response regulator. In negative control, the transmitter module accelerates the rate of phospho-receiver dephosphorylation. This transmitter phosphatase reaction serves the important physiological functions of resetting response regulator phosphorylation level and suppressing cross talk. Although the biochemical reactions underlying positive control are reasonably well-understood, the mechanism for transmitter phosphatase activity has been unknown. A recent hypothesis is that the transmitter phosphatase reaction is catalyzed by a conserved Gln, Asn or Thr residue, via a hydrogen bond between the amide or hydroxyl group and the nucleophilic water molecule in acyl-phosphate hydrolysis. This hypothetical mechanism closely resembles the established mechanisms of auxiliary phosphatases such as CheZ and CheX, and may be widely conserved in two-component signal transduction. In addition to the proposed catalytic residues, transmitter phosphatase activity also requires the correct transmitter conformation and appropriate interactions with the receiver. Evidence suggests that the phosphatase-competent and autokinase-competent states are mutually exclusive, and the corresponding negative and positive activities are likely to be reciprocally regulated through dynamic control of transmitter conformations. PMID:21895797

  5. Characterisation and mechanisms of bradykinin-evoked pain in man using iontophoresis.

    Science.gov (United States)

    Paterson, Kathryn J; Zambreanu, Laura; Bennett, David L H; McMahon, Stephen B

    2013-06-01

    Bradykinin (BK) is an inflammatory mediator that can evoke oedema and vasodilatation, and is a potent algogen signalling via the B1 and B2 G-protein coupled receptors. In naïve skin, BK is effective via constitutively expressed B2 receptors (B2R), while B1 receptors (B1R) are purported to be upregulated by inflammation. The aim of this investigation was to optimise BK delivery to investigate the algesic effects of BK and how these are modulated by inflammation. BK iontophoresis evoked dose- and temperature-dependent pain and neurogenic erythema, as well as thermal and mechanical hyperalgesia (P skin was pretreated with compound 4880 to degranulate the MCs prior to BK challenge. The early phase of BK-evoked pain was reduced in degranulated skin (P wheal, and flare were still evident. In contrast to BK, the B1R selective agonist des-Arg9-BK failed to induce pain or sensitise naïve skin. However, following skin inflammation induced by ultraviolet B irradiation, this compound produced a robust pain response. We have optimised a versatile experimental model by which BK and its analogues can be administered to human skin. We have found that there is an early phase of BK-induced pain which partly depends on the release of inflammatory mediators by MCs; however, subsequent hyperalgesia is not dependent on MC degranulation. In naïve skin, B2R signaling predominates, however, cutaneous inflammation results in enhanced B1R responses. Copyright © 2013 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

  6. Effects of implanted radio transmitters with percutaneous antennas on the behavior of Canada Geese

    Science.gov (United States)

    Hupp, Jerry W.; Ruhl, G.A.; Pearce, John M.; Mulcahy, Daniel M.; Tomeo, M.A.

    2003-01-01

    We examined whether surgically-implanted radio transmitters with percutaneous antennas affected behavior of Lesser Canada Geese (Branta canadensis parvipes) in Anchorage, Alaska. We implanted either a 26-g VHF radio transmitter or a larger VHF radio that was the same mass (35 g) and shape as a satellite transmitter in the coelom of adult females captured during molt in 2000. A control group of females was marked with leg bands. We simultaneously observed behavior of radio-marked and control females from 4-62 d following capture. We observed no differences in the proportion of time birds in different treatments allocated among grazing, resting, comfort, walking, and alert behavior. Females in different treatments spent a similar proportion of time in the water. Implantation of radio transmitters did not affect the frequency of agonistic interactions. We conclude that coelomic radio transmitters with percutaneous antennas had minimal effects on the behavior of Canada Geese.

  7. Wireless heterogeneous transmitter placement using multiobjective variable-length genetic algorithm.

    Science.gov (United States)

    Ting, Chuan-Kang; Lee, Chung-Nan; Chang, Hui-Chun; Wu, Jain-Shing

    2009-08-01

    The problem of placing wireless transmitters to meet particular objectives, such as coverage and cost, has proven to be NP-hard. Furthermore, the heterogeneity of wireless networks makes the problem more intractable to deal with. This paper presents a novel multiobjective variable-length genetic algorithm to solve this problem. One does not need to determine the number of transmitters beforehand; the proposed algorithm simultaneously searches for the optimal number, types, and positions of heterogeneous transmitters by considering coverage, cost, capacity, and overlap. The proposed algorithm can achieve the optimal number of transmitters with coverage exceeding 98% on average for six benchmarks. These preferable experimental results demonstrate the high capability of the proposed algorithm for the wireless heterogeneous transmitter placement problem.

  8. 2-Micron Laser Transmitter for Coherent CO2 DIAL Measurement

    Science.gov (United States)

    Singh, Upendra N.; Bai, Yingxin; Yu, Jirong

    2009-01-01

    Carbon dioxide (CO2) has been recognized as one of the most important greenhouse gases. It is essential for the study of global warming to accurately measure the CO2 concentration in the atmosphere and continuously record its variation. A high repetition rate, highly efficient, Q-switched 2-micron laser system as the transmitter of a coherent differential absorption lidar for CO2 measurement has been developed in NASA Langley Research Center. This laser system is capable of making a vertical profiling of CO2 from ground and column measurement of CO2 from air and space-borne platform. The transmitter is a master-slave laser system. The master laser operates in a single frequency, either on-line or off-line of a selected CO2 absorption line. The slave laser is a Q-switched ring-cavity Ho:YLF laser which is pumped by a Tm:fiber laser. The repetition rate can be adjusted from a few hundred Hz to 10 kHz. The injection seeding success rate is from 99.4% to 99.95%. For 1 kHz operation, the output pulse energy is 5.5mJ with the pulse length of 50 ns. The optical-to-optical efficiency is 39% when the pump power is 14.5W. A Ho:YLF laser operating in the range of 2.05 micrometers can be tuned over several characteristic lines of CO2 absorption. Experimentally, a diode pumped Ho:Tm:YLF laser has been successfully used as the transmitter of coherent differential absorption lidar for the measurement of CO2 with a repetition rate of 5 Hz and pulse energy of 75 mJ. For coherent detection, high repetition rate is required for speckle averaging to obtain highly precise measurements. However, a diode pumped Ho:Tm:YLF laser can not operate in high repetition rate due to the large heat loading and up-conversion. A Tm:fiber laser pumped Ho:YLF laser with low heat loading can operate in high repetition rate. A theoretical model has been established to simulate the performance of Tm:fiber laser pumped Ho:YLF lasers. For continuous wave (CW) operation, high pump intensity with small beam

  9. Glycine is used as a transmitter by decrementing expiratory neurons of the ventrolateral medulla in the rat.

    Science.gov (United States)

    Ezure, Kazuhisa; Tanaka, Ikuko; Kondo, Masahiro

    2003-10-01

    The medullary respiratory network involves various types of respiratory neurons. The present study focused on possible inhibitory neurons called decrementing expiratory (E-DEC) neurons and aimed to determine whether their transmitter is glycine or GABA. In Nembutal-anesthetized, neuromuscularly blocked, and artificially ventilated rats we labeled E-DEC neurons with Neurobiotin and processed the tissues for detection of mRNA encoding either glycine transporter 2 (GLYT2) as a marker for glycinergic neurons or glutamic acid decarboxylase isoform 67 (GAD67) as a marker for GABAergic neurons, using in situ hybridization. Of 38 E-DEC neurons that were labeled, cranial motoneurons (n = 14), which were labeled as control, were negative for either GLYT2 mRNA (n = 10) or GAD67 mRNA (n = 4). The other E-DEC neurons (n = 24) were non-motoneurons. Sixteen of them were examined for GLYT2 mRNA, and the majority (11 of 16) was GLYT2 mRNA-positive. The remaining E-DEC neurons (n = 8) were examined for GAD67 mRNA, and all of them were GAD67 mRNA-negative. The GLYT2 mRNA-positive E-DEC neurons were located in the ventrolateral medulla spanning the Bötzinger complex (BOT), the rostral ventral respiratory group (VRG), and the caudal VRG. We conclude that not only E-DEC neurons of the BOT but also many E-DEC neurons of the VRG are inhibitory and use glycine as a transmitter. Although the present negative data cannot rule out completely the release of GABA or co-release of glycine and GABA from E-DEC neurons, several lines of evidence suggest that the glycinergic process is primarily responsible for the phasic inhibition of the respiratory network during the expiratory phase.

  10. Human auditory evoked potentials. II - Effects of attention

    Science.gov (United States)

    Picton, T. W.; Hillyard, S. A.

    1974-01-01

    Attention directed toward auditory stimuli, in order to detect an occasional fainter 'signal' stimulus, caused a substantial increase in the N1 (83 msec) and P2 (161 msec) components of the auditory evoked potential without any change in preceding components. This evidence shows that human auditory attention is not mediated by a peripheral gating mechanism. The evoked response to the detected signal stimulus also contained a large P3 (450 msec) wave that was topographically distinct from the preceding components. This late positive wave could also be recorded in response to a detected omitted stimulus in a regular train and therefore seemed to index a stimulus-independent perceptual decision process.

  11. Solar active envelope module with an adjustable transmittance/absorptance

    Directory of Open Access Journals (Sweden)

    C. Villasante Villasante

    2015-06-01

    Full Text Available A solar active envelope module with a high flexibility degree is proposed in this paper. The transparent module controls the day-lighting of the room, improving the indoor environment, while absorbing the superfluous solar energy inside. That energy is used to increase the efficiency of heating, ventilation, and the air-conditioning (HVAC system of the building. This is carried out through a fine control of the absorptance of the envelope module. The active envelope module consists of three glazed chambers with advanced coatings and frames to assure a minimum thermal transmittance while allowing transparency. A fluid containing heat-absorbing nanoparticles flows inside the central chamber and is heated up due to the impinging solar energy. Unlike other systems proposed in the past, which included transparency control systems based on complex filters and chemical processes, the absorption of the module is controlled by the variation of the thickness of the central chamber with a mechanical device. That is, varying the thickness of the central chamber, it allows controlling the absorptance of the whole system and, as a result, indoor day-lighting and thermal loads. Therefore, a new system is proposed that enables to:  

  12. Computational Investigations of THz Transmittance in the Atmosphere

    Science.gov (United States)

    Yang, Xingyu; Calhoun, Casey; Calhoun, Ronald

    2016-06-01

    With the recent scientific advancements in Terahertz (THz) wave propagation and reception technology, there has been significant development in new possibilities for using THz waves - offering new possibilities in THz detection and ranging. A first foundational step toward this goal is to better understand THz transmittance in the turbulent atmosphere. In this project, a frequency modulation pattern of THz waves was created by utilizing a system of shifting frequency based on temperature, air humidity, and distance of transmission. The total path loss of the wave in air, based on the wave spread and molecular absorption, was then modeled using radiative transfer theory, onto a set of JavaHAWK filtered-HITRAN data representative of an air sample. This data was used to generate a path loss matrix, which was then used to optimize frequency of transmission for the specific conditions. The concept to be evaluated is whether adaptive frequency modulated THz might usefully decrease transmission losses by adjusting to atmospheric conditions (such as local variations in temperature and humidity).

  13. Development and Testing of a Radio Transmitter for Englacial Trilateration

    Science.gov (United States)

    Kintner, P., III; Winebrenner, D. P.; Elam, T.; Carpenter, M.

    2014-12-01

    Recent need for englacial radiolocation of instrumentation has motivated the construction of a compact radio for GPS style trilateration. The summer of 2014 offered an opportunity to test the radio across the surface of the Greenland ice sheet. A compact crystal oscillator transmitter was developed to operate on the 10 meter amateur band, to put a watt across the transmit antenna. The transmitting antenna used was a coiled dipole antenna, which was tuned in a laboratory ice block. Multiple receive antennas were constructed, a Moxon beam, and two dipole antennas one tuned for air and another tuned for ice. Transmission was tested with a constant tone while positioning the radio above and below the glacier surface. The received signal was well defined at distances of 727m along ice surface despite the complexity and water content. The performance of each receive antenna was judged on a calculated signal to noise ratio. It was theorized the gain from the Moxon beam, reported to be 10dB, would be equal to the loss of signal in the reflection on the ice-air boundary, and thus performance for the Moxon beam and the dipole in ice would be equivalent. Preliminary results suggest this to be true. Previous modeling suggested that a signal to noise ratio above ten would give satisfactory results for trilateration. Here calculated signal to noise was greater at 730m, suggesting that developing a capable receiver would be the next step towards completing englacial trilateration.

  14. Gas detection by using transmittance estimation and segmentation approaches

    Science.gov (United States)

    Özısık Baskurt, Didem; Gür, Yusuf; Ömrüuzun, Fatih; ćetin, Yasemin Yardımcı

    2016-10-01

    Hyperspectral imaging for gas detection applications is an under-researched topic. The same gas model is used in most of the gas detection studies in the literature. This model aims to formulate the scene covering the gas emission as well as the background and the atmosphere. Therefore, the model requires prior knowledge on transmittance, emissivity, and temperature values of the components in the scene. The commonly used approaches to estimate these parameters include atmospheric modeling and statistical inference. However, accessing such information is costly in remote detection applications. Some studies avoid background characterization by decomposing the scene using spectral-spatial information. There are several studies in the literature using this model. They aim to detect various types of gases on different parts of electromagnetic spectrum. Most of these studies use hyperspectral radiance information regarding the scene. However, using brightness temperature map of the data instead of radiance data is more suitable for direct analysis. For this reason, we used brightness temperature spectrum in this study. On the other hand, the detection algorithms are generally based on pixel based investigation. Since the emission of the gas is sourced by a pipe or a chimney, investigating the emission region at the segment level increases detection accuracy. In this study, we used an iterative spectral feature based pixel clustering algorithm followed by spatial segmentation.

  15. Computational Investigations of THz Transmittance in the Atmosphere

    Directory of Open Access Journals (Sweden)

    Yang Xingyu

    2016-01-01

    Full Text Available With the recent scientific advancements in Terahertz (THz wave propagation and reception technology, there has been significant development in new possibilities for using THz waves – offering new possibilities in THz detection and ranging. A first foundational step toward this goal is to better understand THz transmittance in the turbulent atmosphere. In this project, a frequency modulation pattern of THz waves was created by utilizing a system of shifting frequency based on temperature, air humidity, and distance of transmission. The total path loss of the wave in air, based on the wave spread and molecular absorption, was then modeled using radiative transfer theory, onto a set of JavaHAWK filtered-HITRAN data representative of an air sample. This data was used to generate a path loss matrix, which was then used to optimize frequency of transmission for the specific conditions. The concept to be evaluated is whether adaptive frequency modulated THz might usefully decrease transmission losses by adjusting to atmospheric conditions (such as local variations in temperature and humidity.

  16. Effect of nitric oxide on spinal evoked potentials and survival rate in rats with decompression sickness

    DEFF Research Database (Denmark)

    Randsøe, Thomas; Meehan, Claire Francesca; Broholm, Helle

    2015-01-01

    Nitric oxide (NO) releasing agents have, in experimental settings, been shown to decrease intravascular nitrogen bubble formation and to increase the survival rate during decompression sickness (DCS) from diving. The effect has been ascribed to a possible removal of preexisting micronuclei...... evaluated by means of spinal evoked potentials (SEPs). Anesthetized rats were decompressed from a 1-h hyperbaric air dive at 506.6 kPa (40 m of seawater) for 3 min and 17 s, and spinal cord conduction was studied by measurements of SEPs. Histological samples of the spinal cord were analyzed for lesions...... GTN (group 6) during the dive, before decompression. In all groups, decompression caused considerable intravascular bubble formation. The ISMN groups showed no difference compared with the control group, whereas the GTN groups showed a tendency toward faster SEP disappearance and shorter survival...

  17. On the Optimality of Opportunistic Interference Alignment in 3-Transmitter MIMO Interference Channels

    CERN Document Server

    Lee, Jung Hoon; Love, David J

    2011-01-01

    In this paper, we propose opportunistic interference alignment (OIA) for three-transmitter multiple-input multiple-output (MIMO) interference channels (ICs). In the proposed OIA scheme, each transmitter has its own user group that consists of $K$ users, and each transmitter opportunistically selects the user whose received interference signals are most aligned. Thus, three-transmitter MIMO IC is opportunistically constructed by three transmitters and their selected users. Contrary to conventional IA, perfect channel information for all of the interference links is not required at the transmitter. Each user just needs to feed back one scalar value in the proposed OIA scheme. When the number of receive antennas is $N_R$ (with $N_R=2M$) and the number of transmit antennas is $N_T$ (with $N_T\\ge M$), we prove that each transmitter can achieve $M$ degrees of freedom (DoF) as the number of users in each group goes to infinity ($K\\to\\infty$), in comparison with the $\\frac{2M}{3}$ DoF known to be achievable in the th...

  18. Joint Time-Frequency Signal Processing Scheme in Forward Scattering Radar with a Rotational Transmitter

    Directory of Open Access Journals (Sweden)

    Raja Syamsul Azmir Raja Abdullah

    2016-12-01

    Full Text Available This paper explores the concept of a Forward Scattering Radar (FSR system with a rotational transmitter for target detection and localization. Most of the research and development in FSR used a fixed dedicated transmitter; therefore, the detection of stationary and slow moving target is very difficult. By rotating the transmitter, the received signals at the receiver contain extra information carried by the Doppler due to the relative movement of the transmitter-target-receiver. Hence, rotating the transmitter enhances the detection capability especially for a stationary and slow-moving target. In addition, it increases the flexibility of the transmitter to control the signal direction, which broadens the coverage of FSR networks. In this paper, a novel signal processing for the new mode of FSR system based on the signal’s joint time-frequency is proposed and discussed. Additionally, the concept of the FSR system with the rotational transmitter is analyzed experimentally for the detection and localization of a stationary target, at very low speed and a low profile target crossing the FSR baseline. The system acts as a virtual fencing of a remote sensor for area monitoring. The experimental results show that the proposed mode with the new signal processing scheme can detect a human intruder. The potential applications for this system could be used for security and border surveillance, debris detection on an airport runway, ground aerial monitoring, intruder detection, etc.

  19. Proportional Fair Power Allocation for Secondary Transmitters in the TV White Space

    Directory of Open Access Journals (Sweden)

    Konstantinos Koufos

    2013-01-01

    Full Text Available The key bottleneck for secondary spectrum usage is the aggregate interference to the primary system receivers due to simultaneous secondary transmissions. Existing power allocation algorithms for multiple secondary transmitters in the TV white space either fail to protect the TV service in all cases or they allocate extremely low power levels to some of the transmitters. In this paper, we propose a power allocation algorithm that favors equally the secondary transmitters and it is able to protect the TV service in all cases. When the number of secondary transmitters is high, the computational complexity of the proposed algorithm becomes high too. We show how the algorithm could be modified to reduce its computational complexity at the cost of negligible performance loss. The modified algorithm could permit a spectrum allocation database to allocate near optimal transmit power levels to tens of thousands of secondary transmitters in real time. In addition, we describe how the modified algorithm could be applied to allow decentralized power allocation for mobile secondary transmitters. In that case, the proposed algorithm outperforms the existing algorithms because it allows reducing the communication signalling overhead between mobile secondary transmitters and the spectrum allocation database.

  20. Contact heat evoked potentials using simultaneous EEG and fMRI and their correlation with evoked pain

    Directory of Open Access Journals (Sweden)

    Atherton Duncan

    2008-12-01

    Full Text Available Abstract Background The Contact Heat Evoked Potential Stimulator (CHEPS utilises rapidly delivered heat pulses with adjustable peak temperatures to stimulate the differential warm/heat thresholds of receptors expressed by Aδ and C fibres. The resulting evoked potentials can be recorded and measured, providing a useful clinical tool for the study of thermal and nociceptive pathways. Concurrent recording of contact heat evoked potentials using electroencephalogram (EEG and functional magnetic resonance imaging (fMRI has not previously been reported with CHEPS. Developing simultaneous EEG and fMRI with CHEPS is highly desirable, as it provides an opportunity to exploit the high temporal resolution of EEG and the high spatial resolution of fMRI to study the reaction of the human brain to thermal and nociceptive stimuli. Methods In this study we have recorded evoked potentials stimulated by 51°C contact heat pulses from CHEPS using EEG, under normal conditions (baseline, and during continuous and simultaneous acquisition of fMRI images in ten healthy volunteers, during two sessions. The pain evoked by CHEPS was recorded on a Visual Analogue Scale (VAS. Results Analysis of EEG data revealed that the latencies and amplitudes of evoked potentials recorded during continuous fMRI did not differ significantly from baseline recordings. fMRI results were consistent with previous thermal pain studies, and showed Blood Oxygen Level Dependent (BOLD changes in the insula, post-central gyrus, supplementary motor area (SMA, middle cingulate cortex and pre-central gyrus. There was a significant positive correlation between the evoked potential amplitude (EEG and the psychophysical perception of pain on the VAS. Conclusion The results of this study demonstrate the feasibility of recording contact heat evoked potentials with EEG during continuous and simultaneous fMRI. The combined use of the two methods can lead to identification of distinct patterns of brain

  1. Evoked responses to sinusoidally modulated sound in unanaesthetized dogs

    NARCIS (Netherlands)

    Tielen, A.M.; Kamp, A.; Lopes da Silva, F.H.; Reneau, J.P.; Storm van Leeuwen, W.

    1. 1. Responses evoked by sinusoidally amplitude-modulated sound in unanaesthetized dogs have been recorded from inferior colliculus and from auditory cortex structures by means of chronically indwelling stainless steel wire electrodes. 2. 2. Harmonic analysis of the average responses demonstrated

  2. Pattern visual evoked responses in hereditary spastic paraplegia

    Science.gov (United States)

    Livingstone, I R; Mastaglia, F L; Edis, R; Howe, J W

    1981-01-01

    Pattern visual evoked responses were studied in 13 patients from nine families with dominant herditary spastic paraplegia and in seven sporadic cases. The responses were normal in all the dominantly inherited cases but abnormal in three of the seven sporadic cases. PMID:7217977

  3. The role of Magnetic Resonance Imaging and Visual Evoked ...

    African Journals Online (AJOL)

    Introduction: To report our experience in management of patients with optic neuritis. The effects of brain magnetic resonance imaging and visual evoked potential on management were investigated. Methods: This is a four years clinical trial that included patients presenting with first attack of optic neuritis older than 16 years ...

  4. Temporal Tuning Effects in the Visually Evoked Response,

    Science.gov (United States)

    1985-08-01

    Berger (1932) also observed that these brain waves are slowed in states of depressed function such as sleep activity and that they can be blocked by...Ma4cay and Jefferys, 1973). Transient VER’s, polyphasic in form and 200-500 milliseconds in duration, are evoked by stepwise changes in one or more per

  5. Visual evoked potentials in workers with chronic solvent encephalopathy

    NARCIS (Netherlands)

    Verberk, Maarten M.; Brons, Joke T.; Sallé, Herman J. A.

    2004-01-01

    Objectives. Two promising variations of visual evoked potentials (VEPs) were studied in solvent-exposed workers: the effect of a low-contrast stimulus in comparison with the usually applied high contrast, and the ability of pattern-onset VEP to reveal damage to specific visual cortical areas. In

  6. The computation of evoked heart rate and blood pressure

    NARCIS (Netherlands)

    Koers, G.; Mulder, L.J.M.; van der Veen, F.M.

    1999-01-01

    For many years psychophysiologists have been interested in stimulus related changes in heart rate and blood pressure. To represent these evoked heart rate and blood pressure patterns, heart rate and blood pressure data have to be transformed into equidistant time series. This paper presents an

  7. Single-sweep spectral analysis of contact heat evoked potentials

    DEFF Research Database (Denmark)

    Hansen, Tine M; Graversen, Carina; Frøkjaer, Jens B

    2015-01-01

    AIMS: The cortical response to nociceptive thermal stimuli recorded as contact heat evoked potentials (CHEPs) may be altered by morphine. However, previous studies have averaged CHEPs over multiple stimuli, which are confounded by jitter between sweeps. Thus, the aim was to assess single-sweep ch...

  8. The masseteric reflex evoked by tooth and denture tapping.

    Science.gov (United States)

    Brodin, P; Fløystrand, F; Orstavik, J

    1991-07-01

    The characteristics of the masseter reflex evoked by tapping a maxillary incisor were compared with the reflex pattern evoked by tapping a corresponding denture tooth after insertion of an immediate denture. Up to three inhibitory phases (I-1, I-2 and I-3), followed by excitation, were found on an averaged EMG. The tapping force threshold for the early inhibitory phase was lower than for the late phases. The pattern of the reflex was generally the same before and after insertion of the denture, but the threshold values increased. After insertion of the denture, the threshold for I-1 increased from 1 +/- 0.3N to 2.2 +/- 0.4N, the threshold for I-2 increased from 2.4 +/- 0.8N to 3.8 +/- 0.9N, and the threshold for I-3 increased from 5.1 +/- 0.6N to 8.3 +/- 0.9N. The latency period for I-1 also increased from 12.3 +/- 0.5 ms to 13.1 +/- 0.3 ms after insertion of the denture. After relining, the threshold for evoking I-1 decreased from 2.7 +/- 1.2N to 1.2 +/- 0.6N. It was assumed that the mechanoreceptors situated in the mucosa under the denture base could take over the functional role of the periodontal mechanoreceptors for evoking the masseter reflex during tapping, and that these afferents probably had connections to the same interneurones.

  9. The Use of a Solid State Analog Television Transmitter as a Superconducting Electron Gun Power Amplifier

    Energy Technology Data Exchange (ETDEWEB)

    J.G. Kulpin, K.J. Kleman, R.A. Legg

    2012-07-01

    A solid state analog television transmitter designed for 200 MHz operation is being commissioned as a radio frequency power amplifier on the Wisconsin superconducting electron gun cavity. The amplifier consists of three separate radio frequency power combiner cabinets and one monitor and control cabinet. The transmitter employs rugged field effect transistors built into one kilowatt drawers that are individually hot swappable at maximum continuous power output. The total combined power of the transmitter system is 33 kW at 200 MHz, output through a standard coaxial transmission line. A low level radio frequency system is employed to digitally synthesize the 200 MHz signal and precisely control amplitude and phase.

  10. Comparison of clinical and evoked pain measures in fibromyalgia.

    Science.gov (United States)

    Harris, Richard E; Gracely, Richard H; McLean, Samuel A; Williams, David A; Giesecke, Thorsten; Petzke, Frank; Sen, Ananda; Clauw, Daniel J

    2006-07-01

    Evoked pain measures such as tender point count and dolorimetry are often used to determine tenderness in studies of fibromyalgia (FM). However, these measures frequently do not improve in clinical trials and are known to be influenced by factors other than pain such as distress and expectancy. The purpose of this investigation was to determine whether evoked pain paradigms that present pressure stimuli in a random fashion (eg, Multiple Random Staircase [MRS]) would track with clinical pain improvement in patients with FM better than traditional measures. Sixty-five subjects enrolled in a randomized clinical trial of acupuncture were observed longitudinally. Clinical pain was measured on a 101-point numerical rating scale (NRS) and the Short Form McGill Pain Questionnaire (SF-MPQ), whereas evoked pressure sensitivity was assessed via manual tender point count, dolorimetry, and MRS methods. Improvements in clinical pain and evoked pain were assessed irrespective of group assignment. Improvement was seen in clinical pain during the course of the trial as measured by both NRS (P = .032) and SF-MPQ (P = .001). The MRS was the only evoked pain measure to improve correspondingly with treatment (MRS, P = .001; tender point count and dolorimeter, P > .05). MRS change scores were correlated with changes in NRS pain ratings (P = .003); however, this association was not stronger than tender point or dolorimetry correlations with clinical pain improvement (P > .05). Pain sensitivity as assessed by random paradigms was associated with improvements in clinical FM pain. Sophisticated pain testing paradigms might be responsive to change in clinical trials. Trials in fibromyalgia often use both clinical and experimental methods of pain assessment; however, these two outcomes are often poorly correlated. We explore the relationship between changes in clinical and experimental pain within FM patients. Pressure pain testing that applies stimuli in a random order is associated with

  11. Visual evoked potentials in patients after methanol poisoning.

    Science.gov (United States)

    Urban, Pavel; Zakharov, Sergey; Diblík, Pavel; Pelclová, Daniela; Ridzoň, Petr

    2016-01-01

    We report the results of the visual evoked potentials (VEP) examination in patients after severe poisoning by methanol. The group of 47 patients (38 males and 9 females) was assembled out of persons who survived an outbreak of poisoning by the methanol adulterated alcohol beverages, which happened in the Czech Republic in 2012-2013. The visual evoked potentials examination was performed using monocular checkerboard pattern-reversal stimulation. Two criteria of abnormality were chosen: missing evoked response, and wave P1 latency > 117 ms. Non-parametric statistical methods (median, range, and the median test) were used to analyze factors influencing the VEP abnormality. The visual evoked potential was abnormal in 20 patients (43%), 5 of them had normal visual acuity on the Snellen chart. The VEP abnormality did not correlate significantly with initial serum concentrations of methanol, formic acid or lactate; however, it showed statistically significant inverse relation to the initial serum pH: the subgroup with the abnormal VEP had significantly lower median pH in comparison with the subgroup with the normal VEP (7.16 vs. 7.34, p = 0.04). The abnormality was not related to chronic alcohol abuse. The visual evoked potentials examination appeared sensitive enough to detected even subclinical impairment of the optic system. Metabolic acidosis is likely to be the key factor related to the development of visual damage induced by methanol. The examination performed with a delay of 1-9 months after the poisoning documented the situation relatively early after the event. It is considered as a baseline for the planned long-term follow-up of the patients, which will make it possible to assess the dynamics of the observed changes, their reversibility, and the occurrence of potential late sequelae. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

  12. Inhibition by halothane of potassium-stimulated acetylcholine release from rat cortical slices.

    Science.gov (United States)

    Griffiths, R.; Greiff, J. M.; Haycock, J.; Elton, C. D.; Rowbotham, D. J.; Norman, R. I.

    1995-01-01

    1. Cholinergic neurones in the basal forebrain are linked to cortical activation and arousal. 2. The present study was designed to examine the hypothesis that clinically relevant doses of halothane (0.1 to 5%) would significantly reduce depolarization-evoked acetylcholine (ACh) release from rat cortical slices. 3. ACh release was measured from rat cortical slices by a chemiluminescent technique. 4. Depolarization-evoked ACh release was inhibited significantly by halothane with an IC50 of 0.38%. This value equates to 0.3 MAC (the minimum alveolar concentration at which no movement occurs to a standard surgical stimulus in 50% of subjects) for the rat. 5. The potent effect of halothane on ACh release suggests that this mechanism may be a target for the action of volatile anaesthetic agents. This in vitro effect on ACh release is consistent with effects of halothane reported in vivo. PMID:8564265

  13. Imaging of evoked dense-core-vesicle exocytosis in hippocampal neurons reveals long latencies and kiss-and-run fusion events

    OpenAIRE

    Xia, Xiaofeng; Lessmann, Volkmar; Martin, Thomas F. J.

    2008-01-01

    Evoked neuropeptide secretion in the central nervous system occurs slowly, but the basis for slow release is not fully understood. Whereas exocytosis of single synaptic vesicles in neurons and of dense-core vesicles (DCVs) in endocrine cells have been directly visualized, single DCV exocytic events in neurons of the central nervous system have not been previously studied. We imaged DCV exocytosis in primary cultured hippocampal neurons using fluorescent propeptide carg...

  14. Evaluation of isoflurane and propofol anesthesia for intraabdominal transmitter placement in nesting female canvasback ducks.

    Science.gov (United States)

    Machin, K L; Caulkett, N A

    2000-04-01

    Heart rate, occurrence of apnea, body temperature, quality of anesthesia and nest abandonment were compared during either propofol or isoflurane anesthesia of nesting female canvasback ducks (Aythya valisineria) at 15 to 18 days of incubation. One hundred eighteen canvasbacks were assigned randomly to three treatments so that nest abandonment could be compared among treatments from May to July 1995 and 1996. Sterile dummy silicone implants were placed during an abdominal laparotomy while ducks were anesthetized with either propofol or isoflurane, or ducks were flushed from the nest but not captured (control). Propofol was delivered through an intravenous catheter, while isoflurane was delivered in oxygen. Propofol provided smooth, rapid induction and recovery, whereas ducks recovering from isoflurane tended to struggle. At the nest, ducks in the propofol group were given additional boluses until they were lightly anesthetized, whereas birds that received isoflurane were released. All birds survived surgery but one death occurred prior to surgery in 1995 using propofol during a period without ventilation and monitoring. Adequate artificial ventilation is recommended to prevent complications. Heart rate declined significantly in both years during isoflurane anesthesia and in 1995 during propofol anesthesia but not 1996. During both isoflurane and propofol anesthesia, body temperature declined significantly over time. Nest abandonment was significantly different among treatments and occurred in all treatment groups in both years, but propofol (15%) and control groups (8%) had lower than expected abandonment compared to isoflurane (28%). Propofol offers several advantages over isoflurane for field use; equipment is easily portable, lower anesthetic cost, and ambient temperature does not alter physical characteristics of the drug. Advantages over isoflurane, including lower nest abandonment following intraabdominal radio transmitter placement, make propofol a good

  15. Emergency Locator Transmitter System Performance During Three Full-Scale General Aviation Crash Tests

    Science.gov (United States)

    Littell, Justin D.; Stimson, Chad M.

    2016-01-01

    Full-scale crash tests were conducted on three Cessna 172 aircraft at NASA Langley Research Center's Landing and Impact Research facility during the summer of 2015. The purpose of the three tests was to evaluate the performance of commercially available Emergency Locator Transmitter (ELT) systems and support development of enhanced installation guidance. ELTs are used to provide location information to Search and Rescue (SAR) organizations in the event of an aviation distress situation, such as a crash. The crash tests simulated three differing severe but survivable crash conditions, in which it is expected that the onboard occupants have a reasonable chance of surviving the accident and would require assistance from SAR personnel. The first simulated an emergency landing onto a rigid surface, while the second and third simulated controlled flight into terrain. Multiple ELT systems were installed on each airplane according to federal regulations. The majority of the ELT systems performed nominally. In the systems which did not activate, post-test disassembly and inspection offered guidance for non-activation cause in some cases, while in others, no specific cause could be found. In a subset of installations purposely disregarding best practice guidelines, failure of the ELT-to-antenna cabling connections were found. Recommendations for enhanced installation guidance of ELT systems will be made to the Radio Technical Commission for Aeronautics (RTCA) Special Committee 229 for consideration for adoption in a future release of ELT minimum operational performance specifications. These recommendations will be based on the data gathered during this test series as well as a larger series of crash simulations using computer models that will be calibrated based on these data

  16. Cortico-accumbens fiber stimulation does not induce dopamine release in the nucleus accumbens in vitro.

    Science.gov (United States)

    Benoit-Marand, Marianne; O'Donnell, Patricio

    2008-09-01

    Interactions between dopamine (DA) and glutamate in the nucleus accumbens (NA) are important for a variety of cognitive and limbic functions. Although, there is strong evidence that DA controls glutamate responses, the converse (glutamate affecting DA release) is controversial. To determine whether endogenous glutamate released from corticostriatal terminals can evoke DA release by local interactions in the NA, we measured DA release with amperometry simultaneously with whole cell recordings from NA medium spiny neurons (MSNs) in a slice preparation preserving DA terminals (but not cell bodies) and cortico-accumbens fibers. MSNs responded to cortical stimulation with a postsynaptic potential that was blocked by the AMPA antagonist CNQX, but no DA overflow was detected with the carbon fiber electrode. This absence of DA release cannot be accounted for by a deterioration of the DA terminals in this slice preparation since DA release was evoked with a caudal stimulation in the same slices. The DA signal was modulated as expected by bath application of a DA transporter blocker. The data show that cortico-striatal activation does not induce DA release by local interactions, suggesting that observations of glutamate-evoked DA release previously reported in vivo may be taking place via an extra-NA circuit.

  17. Use of a novel acoustic dissolved oxygen transmitter for fish telemetry

    DEFF Research Database (Denmark)

    Svendsen, Jon Christian; Aarestrup, Kim; Steffensen, J.F.

    2006-01-01

    The multiple responses of fishes to changes in dissolved oxygen saturations have been studied widely in the laboratory. In contrast only few studies have included field observations. The objective of the present study was to evaluate the performance of a novel acoustic dissolved oxygen transmitter...... for field biotelemetry. The results demonstrated that the output of the transmitter was unaffected by three different temperatures (10 to 30 degrees C) and described the dissolved oxygen saturation with high accuracy (r(2) > 0.99) over the entire range of 0 to 191% saturation. The response time (>= 90......% of end value) of the transmitter was 12 s both in terms of decreasing (100 to 0%) and increasing (0 to 100%) oxygen saturations. When externally attached to fishes the present findings support the use of the transmitter for reliable dissolved oxygen measurements on individuals living in environments...

  18. High-efficiency resonantly pumped 1550-nm fiber-based laser transmitter Project

    Data.gov (United States)

    National Aeronautics and Space Administration — nLight proposes the development of high efficiency, high average power 1550-nm laser transmitter system that is based on Er-doped fiber amplifier resonantly pumped...

  19. Solid State Transmitters for Water Vapor and Ozone DIAL Systems Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We have developed a common architecture for laser transmitters that address requirements for water vapor as well as ground and airborne ozone lidar systems. Our...

  20. Identification of neurotransmitters and co-localization of transmitters in brainstem respiratory neurons

    Science.gov (United States)

    R.L., Stornetta

    2008-01-01

    Identifying the major ionotropic neurotransmitter in a respiratory neuron is of critical importance in determining how the neuron fits into the respiratory system, whether in producing or modifying respiratory drive and rhythm. There are now several groups of respiratory neurons whose major neurotransmitters have been identified and in some of these cases, more than one transmitter have been identified in particular neurons. This review will describe the physiologically identified neurons in major respiratory areas that have been phenotyped for major ionotropic transmitters as well as those where more than one transmitter has been identified. Although the purpose of the additional transmitter has not been elucidated for any of the respiratory neurons, some examples from other systems will be discussed. PMID:18722563

  1. DESIGN AND IMPLEMENTATION OF A CDMA TRANSMITTER FOR MOBILE CELLULAR COMMUNICATIONS

    Directory of Open Access Journals (Sweden)

    R. Muraoka

    2003-07-01

    Full Text Available In this work we describe the design and implementation of a CDMA transmitter with application on thirdgeneration mobile and personal communication systems. We present several experimental results.

  2. Compact, Rugged and Low-Cost Atmospheric Ozone DIAL Transmitter Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Bridger Photonics Inc. (Bridger) proposes to develop the most compact, efficient and low-cost ultra-violet ozone differential absorption lidar (DIAL) transmitter...

  3. A passively aligned VCSEL transmitter operating at fixed current over a wide temperature range.

    Science.gov (United States)

    Park, Jonghyun; Kim, Taeyong; Kim, Sung-Han; Kim, Sang-Bae

    2009-03-30

    We have investigated low-current operation characteristics of a passively aligned VCSEL transmitter driven at fixed "on" and "off" current over a wide temperature range. GaAs/AlGaAs-based 850-nm oxide VCSELs with the minimum threshold current of 0.79 mA at 50 masculineC and small temperature dependence of the threshold current, d(2)I(th)/dT(2), as low as 0.114 muA/ masculineC(2) have been fabricated and used for the transmitter module. The superior temperature characteristics enable fixed-current operation of the VCSEL transmitter that complies with Gigabit Ethernet standard over a wide temperature range from -20 to 120 masculineC. This result paves the way to a VCSEL transmitter featured by low-power consumption, low-cost with a simple driving circuit and passive alignment, and a wide operation temperature range.

  4. Flexible High Energy Lidar Transmitter for Remote Gas and Wind Sensing Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Fibertek proposes a high energy and flexible operation 1570 nm pulsed lidar transmitter for airborne and space-based remote CO2 gas and doppler wind sensing. The...

  5. Space-Qualifiable 1064 nm Fiber Based Transmitter for Long Range Optical Communications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Fibertek has developed transmitters for Lidar and 3D imaging applications based on fiber optics architectures both at 1064nm. We have demonstrated an all fiber...

  6. Neuronal transporter and astrocytic ATP exocytosis underlie activity-dependent adenosine release in the hippocampus

    Science.gov (United States)

    Wall, Mark J; Dale, Nicholas

    2013-01-01

    The neuromodulator adenosine plays an important role in many physiological and pathological processes within the mammalian CNS. However, the precise mechanisms of how the concentration of extracellular adenosine increases following neural activity remain contentious. Here we have used microelectrode biosensors to directly measure adenosine release induced by focal stimulation in stratum radiatum of area CA1 in mouse hippocampal slices. Adenosine release was both action potential and Ca2+ dependent and could be evoked with low stimulation frequencies and small numbers of stimuli. Adenosine release required the activation of ionotropic glutamate receptors and could be evoked by local application of glutamate receptor agonists. Approximately 40% of stimulated-adenosine release occurred by translocation of adenosine via equilibrative nucleoside transporters (ENTs). This component of release persisted in the presence of the gliotoxin fluoroacetate and thus results from the direct release of adenosine from neurons. A reduction of adenosine release in the presence of NTPDase blockers, in slices from CD73−/− and dn-SNARE mice, provides evidence that a component of adenosine release arises from the extracellular metabolism of ATP released from astrocytes. This component of release appeared to have slower kinetics than the direct ENT-mediated release of adenosine. These data suggest that activity-dependent adenosine release is surprisingly complex and, in the hippocampus, arises from at least two distinct mechanisms with different cellular sources. PMID:23713028

  7. Direct and indirect effects of cannabinoids on in vitro GABA release in the rat arcuate nucleus.

    Science.gov (United States)

    Menzies, J R W; Ludwig, M; Leng, G

    2010-06-01

    Within the hypothalamic arcuate nucleus, two neuronal subpopulations play particularly important roles in energy balance; neurones expressing neuropeptide Y (NPY), agouti-related peptide (AgRP) and GABA are orexigenic, whereas neurones expressing pro-opiomelanocortin and CART are anorexigenic. The pivotal role of these neuropeptides in energy homeostasis is well-known, although GABA may also be an important signal because targeted knockout of the GABA transporter in NPY/AgRP/GABA neurones results in a lean, obesity-resistant phenotype. In the present study, we describe an in vitro model of K(+)-evoked GABA release from the hypothalamus and determine the effects of cannabinoid receptor activation. K(+)-evoked GABA release was sensitive to leptin, insulin and PYY(3-36), indicating that GABA was released by arcuate NPY/AgRP/GABA neurones. In the presence of tetrodotoxin (TTX), the cannabinoid CB1 receptor agonist WIN 55,212-2 inhibited K(+)-evoked GABA release. This was prevented by the CB1 receptor inverse agonist rimonabant. Rimonabant had no effect when applied alone. In the absence of TTX, however, the opposite effects were observed: WIN 55,212-2 had no effect while rimonabant inhibited GABA release. This indicates that GABA release can involve an indirect, TTX-sensitive mechanism. The most parsimonious explanation for the inhibition of GABA release by a CB receptor inverse agonist is via the disinhibition of an cannabinoid-sensitive inhibitory input onto GABAergic neurones. One local source of an inhibitory neurotransmitter is the opioidergic arcuate neurones. In our in vitro model, K(+)-evoked GABA release was inhibited by the endogenous opioid peptide beta-endorphin in a naloxone-sensitive manner. The inhibitory effect of rimonabant was also prevented by naloxone and a kappa-opioid receptor selective antagonist, suggesting that GABA release from arcuate NPY/AgRP/GABA neurones can be inhibited by endogenous opioid peptides, and that the release of opioid

  8. Perancangan Prototipe Transmitter Beacon Black Box Locator Acoustic 37.5 kHz Pingers

    Directory of Open Access Journals (Sweden)

    RUSTAMAJI RUSTAMAJI

    2016-08-01

    Full Text Available ABSTRAK Pingers transmitter berfungsi untuk memancarkan sinyal atau getaran pulsa akustik pada black box. Frekuensi sinyal yang dipancarkan sebesar 37,5 kHz yang dimodulasikan oleh pulsa dengan durasi 10 ms setiap interval 1 second. Modulasi yang digunakan adalah modulasi on off keying. Dalam penelitian ini dibuat perancangan pingers transmitter yang tersusun atas rangkaian osilator, timer, inverter, switch dan rangkaian amplifier. Frekuensi 37,5 kHz tersebut dibangkitkan oleh rangkaian osilator colpitts, sedangkan lebar pulsa dengan durasi 10 ms dan pengulangan pulsa setiap interval 1 second dibangkitkan oleh rangkaian timer. Berdasarkan perancangan yang telah dibuat, output sinyal yang dihasilkan oleh prototipe pingers transmitter tersebut sebesar 37,69 kHz dengan lebar pulsa 9,8 ms setiap interval 1 second. Kata kunci: Black box, pingers transmitter, on off keying. ABSTRACT Pingers transmitter is used to emits a signal or pulse of acoustic vibrations  in black box. The frequency of the transmitted signal is 37.5 kHz which is modulated by pulses with a duration of 10 ms every interval 1 second. The modulation that used this research is on off keying modulation. In this research, made the design of pingers transmitter which arrange of the oscillator circuit,timer, inverter, switch, and amplifier circuit. The 37.5 kHz frequency is generated by the colpitts oscillator circuit, while the pulse width with a duration of 10 ms,and each pulse repetition interval of 1 second generated by timer circuit. Based on the design that have made, signal output from the pingers transmitter prototype is 37.69 kHz, with the pulse width 9.8 ms every 1 second interval. Keywords: Black box, pingers transmitter, on off keying.

  9. Widely Linear Blind Adaptive Equalization for Transmitter IQ-Imbalance/Skew Compensation in Multicarrier Systems

    DEFF Research Database (Denmark)

    Porto da Silva, Edson; Zibar, Darko

    2016-01-01

    Simple analytical widely linear complex-valued models for IQ-imbalance and IQ-skew effects in multicarrier transmitters are presented. To compensate for such effects, a 4×4 MIMO widely linear adaptive equalizer is proposed and experimentally validated.......Simple analytical widely linear complex-valued models for IQ-imbalance and IQ-skew effects in multicarrier transmitters are presented. To compensate for such effects, a 4×4 MIMO widely linear adaptive equalizer is proposed and experimentally validated....

  10. Effects of satellite transmitters on survival in Snowy Owls Bubo scandiacus

    OpenAIRE

    Heggøy, Oddvar; Aarvak, Tomas; Øien, Ingar Jostein; Jacobsen, Karl-Otto; Solheim, Roar; Zazelenchuk, Dan; Stoffel, Marten; Kleven, Oddmund

    2017-01-01

    The use of tracking devices to monitor birds is extensive, but the effects of such instruments on equipped individuals are still insufficiently taken into account. Here we evaluate potential effects of backpack-mounted satellite transmitters (platform terminal transmitters; PTTs) on survival of 28 Snowy Owls Bubo scandiacus. Six confirmed deaths were all probably related to natural and human-induced causes. Although PTT operational time was significantly shorter than expected lifetime of Snow...

  11. A comb laser-driven DWDM silicon photonic transmitter based on microring modulators.

    Science.gov (United States)

    Chen, Chin-Hui; Ashkan Seyedi, M; Fiorentino, Marco; Livshits, Daniil; Gubenko, Alexey; Mikhrin, Sergey; Mikhrin, Vladimir; Beausoleil, Raymond G

    2015-08-10

    We demonstrate concurrent multi-channel transmission at 10 Gbps per channel of a DWDM silicon photonic transmitter. The DWDM transmitter is based on a single quantum dot comb laser and an array of microring resonator-based modulators. The resonant wavelengths of microrings are thermally tuned to align with the wavelengths provided by the comb laser. No obvious crosstalk is observed at 240 GHz channel spacing.

  12. Electromagnetic coupling between transmitters and electro-explosive devices located within an enclosure.

    Energy Technology Data Exchange (ETDEWEB)

    Warne, Larry Kevin; Jorgenson, Roy Eberhardt; Coats, Rebecca Sue

    2010-04-01

    This report documents calculations conducted to determine if 42 low-power transmitters located within a metallic enclosure can initiate electro-explosive devices (EED) located within the same enclosure. This analysis was performed for a generic EED no-fire power level of 250 mW. The calculations show that if the transmitters are incoherent, the power available is 32 mW - approximately one-eighth of the assumed level even with several worst-case assumptions in place.

  13. Comparative Evaluation of Spectral Transmittance of Some Welding Glasses with ANSI Z87.1

    OpenAIRE

    saeed Rahmani; Alireza Akbarzadeh Baghban; Mohammadreza Nazari; Mohammad Ghassemi-Broumand

    2016-01-01

    Background: Welding emits harmful rays to the eyes. We evaluate and compare the UV, blue light and IR transmittance characteristics of some currently available welding safety protectors with ANSI Z87.1 criteria.Materials and Methods: Three type of welding safety protectors (three of each type) have been evaluated for spectral transmittance. One-sample T-test was performed to establish is there a statistically significant difference between the standard criteria and UV, blue and IR regions for...

  14. Total canopy transmittance estimated from small-footprint, full-waveform airborne LiDAR

    Science.gov (United States)

    Milenković, Milutin; Wagner, Wolfgang; Quast, Raphael; Hollaus, Markus; Ressl, Camillo; Pfeifer, Norbert

    2017-06-01

    Canopy transmittance is a directional and wavelength-specific physical parameter that quantifies the amount of radiation attenuated when passing through a vegetation layer. The parameter has been estimated from LiDAR data in many different ways over the years. While early LiDAR methods treated each returned echo equally or weighted the echoes according to their return order, recent methods have focused more on the echo energy. In this study, we suggest a new method of estimating the total canopy transmittance considering only the energy of ground echoes. Therefore, this method does not require assumptions for the reflectance or absorption behavior of vegetation. As the oblique looking geometry of LiDAR is explicitly considered, canopy transmittance can be derived for individual laser beams and can be mapped spatially. The method was applied on a contemporary full-waveform LiDAR data set collected under leaf-off conditions and over a study site that contains two sub regions: one with a mixed (coniferous and deciduous) forest and another that is predominantly a deciduous forest in an alluvial plain. The resulting canopy transmittance map was analyzed for both sub regions and compared to aerial photos and the well-known fractional cover method. A visual comparison with aerial photos showed that even single trees and small canopy openings are visible in the canopy transmittance map. In comparison with the fractional cover method, the canopy transmittance map showed no saturation, i.e., there was better separability between patches with different vegetation structure.

  15. Prediction of transmittance spectra for transparent composite electrodes with ultra-thin metal layers

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Zhao; Alford, T. L., E-mail: TA@asu.edu [School for Engineering of Matter, Transport, and Energy, Arizona State University, Tempe, Arizona 85287 (United States); Khorasani, Arash Elhami [ON Semiconductor Corp., Phoenix, Arizona 85005 (United States); Theodore, N. D. [CHD-Fab, Freescale Semiconductor Inc., Tempe, Arizona 85224 (United States); Dhar, A. [Intel Corp., 2501 NW 229th Ave, Hillsboro, Oregon 97124 (United States)

    2015-11-28

    Recent interest in indium-free transparent composite-electrodes (TCEs) has motivated theoretical and experimental efforts to better understand and enhance their electrical and optical properties. Various tools have been developed to calculate the optical transmittance of multilayer thin-film structures based on the transfer-matrix method. However, the factors that affect the accuracy of these calculations have not been investigated very much. In this study, two sets of TCEs, TiO{sub 2}/Au/TiO{sub 2} and TiO{sub 2}/Ag/TiO{sub 2}, were fabricated to study the factors that affect the accuracy of transmittance predictions. We found that the predicted transmittance can deviate significantly from measured transmittance for TCEs that have ultra-thin plasmonic metal layers. The ultrathin metal layer in the TCE is typically discontinuous. When light interacts with the metallic islands in this discontinuous layer, localized surface plasmons are generated. This causes extra light absorption, which then leads to the actual transmittance being lower than the predicted transmittance.

  16. Efficient Compensation of Transmitter and Receiver IQ Imbalance in OFDM Systems

    Directory of Open Access Journals (Sweden)

    Tandur Deepaknath

    2010-01-01

    Full Text Available Radio frequency impairments such as in-phase/quadrature-phase (IQ imbalances can result in a severe performance degradation in direct-conversion architecture-based communication systems. In this paper, we consider the case of transmitter and receiver IQ imbalance together with frequency selective channel distortion. The proposed training-based schemes can decouple the compensation of transmitter and receiver IQ imbalance from the compensation of channel distortion in an orthogonal frequency division multiplexing (OFDM systems. The presence of frequency selective channel fading is a requirement for the estimation of IQ imbalance parameters when both transmitter/receiver IQ imbalance are present. However, the proposed schemes are equally applicable over a frequency flat/frequency selective channel when either transmitter or only receiver IQ imbalance is present. Once the transmitter and receiver IQ imbalance parameters are estimated, a standard channel equalizer can be applied to estimate/compensate for the channel distortion. The proposed schemes result in an overall lower training overhead and a lower computational requirement, compared to the joint compensation of transmitter/receiver IQ imbalance and channel distortion. Simulation results demonstrate that the proposed schemes provide a very efficient compensation with performance close to the ideal case without any IQ imbalance.

  17. Effects of radio transmitters on the behavior of Red-headed Woodpeckers.

    Energy Technology Data Exchange (ETDEWEB)

    Vukovich, Mark; Kilgo, John, C.

    2009-05-01

    ABSTRACT. Previous studies have revealed that radio-transmitters may affect bird behaviors, including feeding rates, foraging behavior, vigilance, and preening behavior. In addition, depending on the method of attachment, transmitters can potentially affect the ability of cavity-nesting birds to use cavities. Our objective was to evaluate effects of transmitters on the behavior of and use of cavities byRed-headedWoodpeckers (Melanerpes erythrocephalus). Using backpack harnesses, we attached 2.1-g transmitter packages that averaged 3.1% of body weight (range = 2.5–3.6%) to Red-headed Woodpeckers. We observed both radio-tagged (N = 23) and nonradio-tagged (N = 28) woodpeckers and determined the percentage of time spent engaged in each of five behaviors: flight, foraging, perching, preening, and territorial behavior. We found no difference between the two groups in the percentage of time engaged in each behavior. In addition, we found that transmitters had no apparent effect on use of cavities for roosting by radio-tagged woodpeckers (N = 25).We conclude that backpack transmitters weighing less than 3.6% of body weight had no impact on either their behavior or their ability to use cavities.

  18. A 4 Gbps current-mode transmitter for 12-bit 250 MSPS ADC

    Science.gov (United States)

    Chen, Zhenhai; Yu, Zongguang; Wei, Jinghe; Zhou, Dejin; Su, Xiaobo; Zou, Jiaxuan

    2017-08-01

    A 4 Gbps transmitter for a 12-bit 250 MSPS pipelined ADCs is presented. A low power current mode (CM) output driver with reverse scaling technique is proposed. A high speed, low power combined serializer is implemented to convert 12 bit parallel data into a seria1 data stream. The whole transmitter is used in a 12-bit 250 MSPS pipelined ADC for the digital output buffer and fabricated in 180 nm 1. 8 V 1P5M CMOS technology. Test results show that the transmitter provides an eye height greater than 800 mV for data rates of both 2 Gbps and 4 Gbps, the 12-bit 250 MSPS ADC achieves the SNR of 69.92 dBFS and SFDR of 81.17 dB with 20.1 MHz input at full sampling speed. The ADC with the 4 Gbps transmitter consumes the power consumption of 395 mW, where the power consumption of transmitter is 75 mW. The ADC occupies an area of 2.5× 3.2 {{mm}}2, where the active area of the transmitter block is 0.5× 1.2 {{mm}}2. Project supported by the National Science Foundation of China (No. 61474092) and Key Project of Natural Science of Anhui Provincial Department of Education (No. KJ2017A396).

  19. Clinical evaluation of cochlear hearing status in dogs using evoked otoacoustic emissions.

    Science.gov (United States)

    Gonçalves, R; McBrearty, A; Pratola, L; Calvo, G; Anderson, T J; Penderis, J

    2012-06-01

    Evoked otoacoustic emission testing is the preferred test in human patients for sensorineural deafness screening in neonates and cochlear outer hair cell function monitoring in adults. This study evaluated evoked otoacoustic emission testing for cochlear function assessment in dogs within a clinical setting. Two populations of anaesthetised dogs were included. In group 1 the evoked otoacoustic emission response was compared to the brainstem auditory evoked response in 10 dogs having hearing assessment. Group 2 comprised 43 presumed normal dogs, in which the suitability of two types of evoked otoacoustic emissions, transient-evoked and distortion product otoacoustic emissions, were evaluated (brainstem auditory evoked response was not performed in this group). Valid transient-evoked otoacoustic emission and distortion-product otoacoustic emission responses were successfully recorded within the clinical setting and correctly identified deaf and hearing ears. Within presumed healthy dogs, normal otoacoustic emission response was demonstrated in more than 80% of dogs using a single, short distortion-product otoacoustic emission run and in 78% of dogs with valid transient-evoked otoacoustic emission responses using a series of three repeated transient-evoked otoacoustic emission short runs. Transient-evoked otoacoustic emission and distortion-product otoacoustic emission testing provided a rapid, non-invasive frequency-specific assessment of cochlear function. Transient-evoked otoacoustic emission and distortion product otoacoustic emission testing is suitable as a screening procedure to detect loss of cochlear function in dogs, although further investigation is needed. © 2012 British Small Animal Veterinary Association.

  20. An inventory and update of jealousy-evoking partner behaviours in modern society.

    NARCIS (Netherlands)

    Dijkstra, Pieternel; Barelds, Dick P. H.; Groothof, Hinke A. K.

    2010-01-01

    The goal of the present study was to identify the most important jealousy-evoking partner behaviours and to examine the extent to which these behaviours evoke jealousy. Based on the literature, a questionnaire was constructed containing 42 jealousy-evoking partner behaviours, including a partner's

  1. Localized neurotransmitter release for use in a prototype retinal interface.

    Science.gov (United States)

    Peterman, Mark C; Bloom, David M; Lee, Christina; Bent, Stacey F; Marmor, Michael F; Blumenkranz, Mark S; Fishman, Harvey A

    2003-07-01

    Current neural prostheses use electricity as the mode of stimulation, yet information transfer in neural circuitry is primarily through chemical transmitters. To address this disparity, this study was conducted to devise a prototype interface for a retinal prosthetic based on localized chemical delivery. The goal was to determine whether fluidic delivery through microfabricated apertures could be used to stimulate at single-cell dimensions. A drug delivery system was microfabricated based on a 5- or 10- microm aperture in a 500-nm thick silicon nitride membrane to localize and limit transmitter release. The aperture overlies a microfluidic delivery channel in a silicone elastomer. To demonstrate the effectiveness of this transmitter-based prosthesis, rat pheochromocytoma cells (PC12 cell line) were grown on the surface of the device to test the precision of stimulation, using bradykinin as a stimulant and measuring fluorescence from the calcium indicator, fluo-4. The extent of stimulation could be controlled accurately by varying the concentration of stimulant, from a single cell adjacent to the aperture to a broad area of cells. The stimulation radius was as small as 10 microm, corresponding to stimulation volumes as small as 2 pL. The relationship between the extent of stimulation and concentration was linear. The demonstration of localized chemical stimulation of excitable cells illustrates the potential of this technology for retinal prostheses. Although this is only a proof of concept of neurotransmitter stimulation for a retinal prosthesis, it is a significant first step toward mimicking neurotransmitter release during synaptic transmission.

  2. Transmitter-receiver system for time average fourier telescopy

    Science.gov (United States)

    Pava, Diego Fernando

    Time Average Fourier Telescopy (TAFT) has been proposed as a means for obtaining high-resolution, diffraction-limited images over large distances through ground-level horizontal-path atmospheric turbulence. Image data is collected in the spatial-frequency, or Fourier, domain by means of Fourier Telescopy; an inverse twodimensional Fourier transform yields the actual image. TAFT requires active illumination of the distant object by moving interference fringe patterns. Light reflected from the object is collected by a "light-buckt" detector, and the resulting electrical signal is digitized and subjected to a series of signal processing operations, including an all-critical averaging of the amplitude and phase of a number of narrow-band signals. This dissertation reports on the formulation and analysis of a transmitter-receiver system appropriate for the illumination, signal detection, and signal processing required for successful application of the TAFT concept. The analysis assumes a Kolmogorov model for the atmospheric turbulence, that the object is rough on the scale of the optical wavelength of the illumination pattern, and that the object is not changing with time during the image-formation interval. An important original contribution of this work is the development of design principles for spatio-temporal non-redundant arrays of active sources for object illumination. Spatial non-redundancy has received considerable attention in connection with the arrays of antennas used in radio astronomy. The work reported here explores different alternatives and suggests the use of two-dimensional cyclic difference sets, which favor low frequencies in the spatial frequency domain. The temporal nonredundancy condition requires that all active sources oscillate at a different optical frequency and that the frequency difference between any two sources be unique. A novel algorithm for generating the array, based on optimized perfect cyclic difference sets, is described

  3. Local anesthetics inhibit glutamate release from rat cerebral cortex synaptosomes.

    Science.gov (United States)

    Lin, Tzu-Yu; Chung, Chih-Yang; Lu, Cheng-Wei; Huang, Shu-Kuei; Shieh, Jiann-Sing; Wang, Su-Jane

    2013-09-01

    Local anesthetics have been widely used for regional anesthesia and the treatment of cardiac arrhythmias. Recent studies have also demonstrated that low-dose systemic local anesthetic infusion has neuroprotective properties. Considering the fact that excessive glutamate release can cause neuronal excitotoxicity, we investigated whether local anesthetics might influence glutamate release from rat cerebral cortex nerve terminals (synaptosomes). Results showed that two commonly used local anesthetics, lidocaine and bupivacaine, exhibited a dose-dependent inhibition of 4-AP-evoked release of glutamate. The effects of lidocaine or bupivacaine on the evoked glutamate release were prevented by the chelation of extracellular Ca²⁺ ions and the vesicular transporter inhibitor bafilomycin A1. However, the glutamate transporter inhibitor dl-threo-beta-benzyl-oxyaspartate did not have any effect on the action of lidocaine or bupivacaine. Both lidocaine and bupivacaine reduced the depolarization-induced increase in [Ca²⁺]C but did not alter 4-AP-mediated depolarization. Furthermore, the inhibitory effect of lidocaine or bupivacaine on evoked glutamate release was prevented by blocking the Ca(v)2.2 (N-type) and Ca(v)2.1 (P/Q-type) channels, but it was not affected by blocking of the ryanodine receptors or the mitochondrial Na⁺/Ca²⁺ exchange. Inhibition of protein kinase C (PKC) and protein kinase A (PKA) also prevented the action of lidocaine or bupivacaine. These results show that local anesthetics inhibit glutamate release from rat cortical nerve terminals. This effect is linked to a decrease in [Ca²⁺]C caused by Ca²⁺ entry through presynaptic voltage-dependent Ca²⁺ channels and the suppression of the PKA and PKC signaling cascades. Copyright © 2013 Wiley Periodicals, Inc.

  4. [Motor evoked potentials of the perineal floor. Preliminary results].

    Science.gov (United States)

    Opsomer, R J; Van Cangh, P J; Humblet, Y; Abi Aad, A; Rossini, P M

    1989-01-01

    Neuromotor pathways from the brain to the pelvic floor have been poorly documented. The recent development of Motor Evoked Potentials may well fill this gap in our basic knowledge. Our technique consists of transcutaneous stimulation of the motor cortex and sacral roots with a magnetic device while recording the evoked response from the bulbocavernosus muscle and anal sphincter. Cortical stimulation is performed first at rest and then during voluntary contraction of the examined muscles ("facilitation" procedure). Sacral root stimulation is performed at rest. Stimulation at 2 different levels allows measurement of the total transit time (brain to muscle transit time) and the peripheral transit time (sacral roots to muscle). By subtracting the latter from the former, the central transit time (brain to sacral roots) is obtained. The technique is painless, and to our knowledge no side effects have been reported. The authors present the preliminary results of this new technique.

  5. Evoked potentials and head injury. 2. Clinical applications.

    Science.gov (United States)

    Rappaport, M; Hopkins, H K; Hall, K; Belleza, T

    1981-10-01

    The method of rating abnormality of evoked brain potential patterns and assessing the extent and severity of cortical and subcortical brain dysfunction in head injury patients described in Part I is applied in a clinical context. Evoked potential abnormality (EPA) scores are found to be significantly correlated both with admission and outcome disability approximately one year after head injury. Correlations increase with the increase in the number of sensory modalities tested. Correlations between EPA scores and clinical disability (measured by the Disability Rating Scale) decrease with time after injury. Significant correlations, however, persist for about 60 days after onset of injury. It was found that EP pattern abnormalities can reflect specific sensory (and at times motor) deficits in noncommunicative patients and thereby contribute significantly to early treatment and rehabilitation planning.

  6. Binocular interactions in the guinea pig's visual-evoked potentials.

    Science.gov (United States)

    Ates, Kahraman; Demirtas, Serdar; Goksoy, Cuneyt

    2006-12-13

    In this study, binocular interaction in guinea pigs is evaluated using bioelectrical activities. A difference potential, as evidence of an interaction, is calculated by subtracting the sum of visual-evoked potentials recorded by left and right monocular visual stimulations from the potential recorded by binocular stimulation. A negative monophasic wave with an average amplitude of 15.1 microV and an average latency of 106 ms is observed in the difference potential. This finding implies that the P100 is the main guinea pig visual-evoked potential wave that is affected by binocular interaction. Binocular interaction is also observed in the waves N75 and N140, although with a smaller amplitude. No interaction is observed in the segments of P55 and P200 waves.

  7. Multimodality evoked potentials in occupational exposure to metallic mercury vapour.

    Science.gov (United States)

    Langauer-Lewowicka, H; Kazibutowska, Z

    1989-01-01

    Central nervous system dysfunction among workers exposed to metallic mercury was studied by measuring somatosensory evoked potentials (SSEPs) and visual evoked potentials (VEPs). The examinations were conducted in 28 workers suspected of chronic mercury intoxication. They were exposed to Hg for a period ranging from 4-34 years (mean 22.1) in an acetic aldehyde and chlorine manufacturing plant. The increase of amplitude of N20 SSEP (13 cases) and elongation of its latency were frequent abnormalities in the examined group. The latency of N20 was significantly longer in the exposed group in comparison with the control one, the amplitude of N20 was also significantly higher. Significantly prolonged latency of P100 VEP was found in the group exposed to Hg. These findings suggest the possibility of an adverse effect due to Hg on the central part of the somatosensory and visual pathway.

  8. Automatic classification of visual evoked potentials based on wavelet decomposition

    Science.gov (United States)

    Stasiakiewicz, Paweł; Dobrowolski, Andrzej P.; Tomczykiewicz, Kazimierz

    2017-04-01

    Diagnosis of part of the visual system, that is responsible for conducting compound action potential, is generally based on visual evoked potentials generated as a result of stimulation of the eye by external light source. The condition of patient's visual path is assessed by set of parameters that describe the time domain characteristic extremes called waves. The decision process is compound therefore diagnosis significantly depends on experience of a doctor. The authors developed a procedure - based on wavelet decomposition and linear discriminant analysis - that ensures automatic classification of visual evoked potentials. The algorithm enables to assign individual case to normal or pathological class. The proposed classifier has a 96,4% sensitivity at 10,4% probability of false alarm in a group of 220 cases and area under curve ROC equals to 0,96 which, from the medical point of view, is a very good result.

  9. Evoked response audiometry used in testing auditory organs of miners

    Energy Technology Data Exchange (ETDEWEB)

    Malinowski, T.; Klepacki, J.; Wagstyl, R.

    1980-01-01

    The evoked response audiometry method of testing hearing loss is presented and the results of comparative studies using subjective tonal audiometry and evoked response audiometry in tests of 56 healthy men with good hearing are discussed. The men were divided into three groups according to age and place of work: work place without increased noise; work place with noise and vibrations (at drilling machines); work place with noise and shocks (work at excavators in surface coal mines). The ERA-MKII audiometer produced by the Medelec-Amplaid firm was used. Audiometric threshhold curves for the three groups of tested men are given. At frequencies of 500, 1000 and 4000 Hz mean objective auditory threshhold was shifted by 4-9.5 dB in comparison to the subjective auditory threshold. (21 refs.) (In Polish)

  10. Abdominal acupuncture reduces laser-evoked potentials in healthy subjects

    DEFF Research Database (Denmark)

    Pazzaglia, C.; Liguori, S.; Minciotti, I.

    2015-01-01

    Objective: Acupuncture is known to reduce clinical pain, although the exact mechanism is unknown. The aim of the current study was to investigate the effect of acupuncture on laser-evoked potential amplitudes and laser pain perception. Methods: In order to evaluate whether abdominal acupuncture...... is able to modify pain perception, 10 healthy subjects underwent a protocol in which laser-evoked potentials (LEPs) and laser pain perception were collected before the test (baseline), during abdominal acupuncture, and 15. min after needle removal. The same subjects also underwent a similar protocol...... in which, however, sham acupuncture without any needle penetration was used. Results: During real acupuncture, both N1 and N2/P2 amplitudes were reduced, as compared to baseline (p . < 0.01). The reduction lasted up to 15. min after needle removal. Furthermore, laser pain perception was reduced during...

  11. Rapid shallow breathing evoked by selective stimulation of airway C fibres in dogs.

    Science.gov (United States)

    Coleridge, H M; Coleridge, J C; Roberts, A M

    1983-07-01

    rate were complex and appeared to result from the interplay of several reflexes. Marked cardiac slowing was evoked by bradykinin aerosol.6. Bradykinin injected into a bronchial artery is known to stimulate bronchial (intrapulmonary) C fibres. Results of recording afferent vagal impulses in the present study indicated that bradykinin administered as an aerosol stimulated bronchial C fibres and also C fibres with endings in the lower trachea and extrapulmonary bronchi. Irritant and pulmonary stretch receptors were not stimulated unless aerosols were administered repeatedly and in higher concentration. Hence airway C fibres appeared to be responsible for the reflex effects of bradykinin aerosol.7. Bronchial C fibres are stimulated by substances (bradykinin, prostaglandins and histamine) known to be released by the lungs and airways in a variety of pathophysiological circumstances. Results of this and previous studies are compatible with the hypothesis that stimulation of bronchial C fibres plays a major role in evoking the rapid shallow breathing, bronchoconstriction and increased secretion by airway submucosal glands that are part of the pulmonary defence response.

  12. The Dynamic Functional Capacity Theory: Music Evoked Emotions

    OpenAIRE

    Klineburger, Philip C

    2014-01-01

    The music-evoked emotion literature implicates many brain regions involved in emotional processing but is currently lacking a model that specifically explains how they temporally and dynamically interact to produce intensely pleasurable emotions. A conceptual model, The Dynamic Functional Capacity Theory (DFCT), is proposed that provides a foundation for the further understanding of how brain regions interact to produce intense intensely pleasurable emotions. The DFCT claims th...

  13. Multimodality evoked potentials in HTLV-I associated myelopathy.

    OpenAIRE

    Kakigi, R; Shibasaki, H; Kuroda, Y; Endo, C; Oda, K; Ikeda, A; Hashimoto, K

    1988-01-01

    Multimodality evoked potentials (EPs) consisting of somatosensory EPs (SEPs), visual EPs (VEPs) and brainstem auditory EPs (BAEPs) were studied in 16 cases with HTLV-I associated myelopathy (HAM). Median nerve SEPs were normal in all cases. In posterior tibial nerve SEPs, the potential recorded at the 12th thoracic spinal process was normal in every case but cortical components were significantly prolonged in 10 cases, although five of these showed no sensory impairment. BAEPs were normal in ...

  14. Establishing an evoked-potential vision-tracking system

    Science.gov (United States)

    Skidmore, Trent A.

    1991-01-01

    This paper presents experimental evidence to support the feasibility of an evoked-potential vision-tracking system. The topics discussed are stimulator construction, verification of the photic driving response in the electroencephalogram, a method for performing frequency separation, and a transient-analysis example. The final issue considered is that of object multiplicity (concurrent visual stimuli with different flashing rates). The paper concludes by discussing several applications currently under investigation.

  15. An uncovered risk factor of sonothrombolysis: Substantial fluctuation of ultrasound transmittance through the human skull.

    Science.gov (United States)

    Wang, Zuojun; Komatsu, Teppei; Mitsumura, Hidetaka; Nakata, Norio; Ogawa, Takeki; Iguchi, Yasuyuki; Yokoyama, Masayuki

    2017-05-01

    Sonothrombolysis is one of the most feasible methods for enhancing clot lysis with a recombinant tissue plasminogen activator (rt-PA) in cases of acute ischemic strokes. For safe and efficient clinical practices of sonothrombolysis, accurate estimation of ultrasound transmittance through the human skull is critical. Previously, we reported substantial and periodic fluctuation of ultrasound transmittance through a bone-phantom plate following changes to ultrasound frequency, the thickness of the bone-phantom plate, and the distance between a transducer and the bone-phantom plate. In the present study, we clarify the transmittance behavior of medium-frequency ultrasound (from 400kHz to 600kHz) through the human skull, and examine reduction of the transmittance fluctuation. For the study, we measured transmittance of sinusoidal ultrasound waves at 400kHz, 500kHz, and 600kHz at 13 temple spots on 3 human skulls by changing the distance between a transducer and the skull bone, and found substantial and periodic fluctuation in the transmittance behaviors for these sinusoidal voltage excitations. Degrees of the fluctuation varied depending on the measurement spots. A fluctuation ratio between the maximum transmittance and the minimum transmittance reached 3 in some spots. This large transmittance fluctuation is considered to be a risk factor for sonothrombolysis therapies. We examined a modulated ultrasound wave to reduce the fluctuation, and succeeded in obtaining considerable reduction. The average fluctuation ratios for 400-kHz, 500-kHz, and 600-kHz waves were 2.38, 2.38, and 2.07, respectively. We successfully reduced the ratio to 1.72 by using a periodic selection of random frequency (PSRF)-type of modulation wave. The thus obtained results indicate that attention to the fluctuation in ultrasound transmittance through the skull is necessary for safe and effective sonothrombolysis therapies, and that modulated ultrasound waves constitute a powerful method for reducing

  16. Perceptual learning of acoustic noise generates memory-evoked potentials.

    Science.gov (United States)

    Andrillon, Thomas; Kouider, Sid; Agus, Trevor; Pressnitzer, Daniel

    2015-11-02

    Experience continuously imprints on the brain at all stages of life. The traces it leaves behind can produce perceptual learning [1], which drives adaptive behavior to previously encountered stimuli. Recently, it has been shown that even random noise, a type of sound devoid of acoustic structure, can trigger fast and robust perceptual learning after repeated exposure [2]. Here, by combining psychophysics, electroencephalography (EEG), and modeling, we show that the perceptual learning of noise is associated with evoked potentials, without any salient physical discontinuity or obvious acoustic landmark in the sound. Rather, the potentials appeared whenever a memory trace was observed behaviorally. Such memory-evoked potentials were characterized by early latencies and auditory topographies, consistent with a sensory origin. Furthermore, they were generated even on conditions of diverted attention. The EEG waveforms could be modeled as standard evoked responses to auditory events (N1-P2) [3], triggered by idiosyncratic perceptual features acquired through learning. Thus, we argue that the learning of noise is accompanied by the rapid formation of sharp neural selectivity to arbitrary and complex acoustic patterns, within sensory regions. Such a mechanism bridges the gap between the short-term and longer-term plasticity observed in the learning of noise [2, 4-6]. It could also be key to the processing of natural sounds within auditory cortices [7], suggesting that the neural code for sound source identification will be shaped by experience as well as by acoustics. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Brainstem auditory evoked potentials in children with lead exposure

    Directory of Open Access Journals (Sweden)

    Katia de Freitas Alvarenga

    2015-02-01

    Full Text Available Introduction: Earlier studies have demonstrated an auditory effect of lead exposure in children, but information on the effects of low chronic exposures needs to be further elucidated. Objective: To investigate the effect of low chronic exposures of the auditory system in children with a history of low blood lead levels, using an auditory electrophysiological test. Methods: Contemporary cross-sectional cohort. Study participants underwent tympanometry, pure tone and speech audiometry, transient evoked otoacoustic emissions, and brainstem auditory evoked potentials, with blood lead monitoring over a period of 35.5 months. The study included 130 children, with ages ranging from 18 months to 14 years, 5 months (mean age 6 years, 8 months ± 3 years, 2 months. Results: The mean time-integrated cumulative blood lead index was 12 µg/dL (SD ± 5.7, range:2.433. All participants had hearing thresholds equal to or below 20 dBHL and normal amplitudes of transient evoked otoacoustic emissions. No association was found between the absolute latencies of waves I, III, and V, the interpeak latencies I-III, III-V, and I-V, and the cumulative lead values. Conclusion: No evidence of toxic effects from chronic low lead exposures was observed on the auditory function of children living in a lead contaminated area.

  18. Brainstem auditory evoked potentials in children with lead exposure.

    Science.gov (United States)

    Alvarenga, Katia de Freitas; Morata, Thais Catalani; Lopes, Andrea Cintra; Feniman, Mariza Ribeiro; Corteletti, Lilian Cassia Bornia Jacob

    2015-01-01

    Earlier studies have demonstrated an auditory effect of lead exposure in children, but information on the effects of low chronic exposures needs to be further elucidated. To investigate the effect of low chronic exposures of the auditory system in children with a history of low blood lead levels, using an auditory electrophysiological test. Contemporary cross-sectional cohort. Study participants underwent tympanometry, pure tone and speech audiometry, transient evoked otoacoustic emissions, and brainstem auditory evoked potentials, with blood lead monitoring over a period of 35.5 months. The study included 130 children, with ages ranging from 18 months to 14 years, 5 months (mean age 6 years, 8 months ± 3 years, 2 months). The mean time-integrated cumulative blood lead index was 12 μg/dL (SD ± 5.7, range: 2.433). All participants had hearing thresholds equal to or below 20 dBHL and normal amplitudes of transient evoked otoacoustic emissions. No association was found between the absolute latencies of waves I, III, and V, the interpeak latencies I-III, III-V, and I-V, and the cumulative lead values. No evidence of toxic effects from chronic low lead exposures was observed on the auditory function of children living in a lead contaminated area. Copyright © 2014 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

  19. Index finger somatosensory evoked potentials in blind Braille readers.

    Science.gov (United States)

    Giriyappa, Dayananda; Subrahmanyam, Roopakala Mysore; Rangashetty, Srinivasa; Sharma, Rajeev

    2009-01-01

    Traditionally, vision has been considered the dominant modality in our multi-sensory perception of the surrounding world. Sensory input via non-visual tracts becomes of greater behavioural relevance in totally blind individuals to enable effective interaction with the world around them. These include audition and tactile perceptions, leading to an augmentation in these perceptions when compared with normal sighted individuals. The objective of the present work was to study the index finger somatosensory evoked potentials (SEPs) in totally blind and normal sighted individuals. SEPs were recorded in 15 Braille reading totally blind females and compared with 15 age-matched normal sighted females. Latency and amplitudes of somatosensory evoked potential waveforms (N9, N13, and N20) were measured. Amplitude of N20 SEP (a cortical somatosensory evoked potential) was significantly larger in the totally blind than in normal sighted individuals (p Braille reading right index finger. Totally blind Braille readers have larger N20 amplitude, suggestive of greater somatosensory cortical representation of the Braille reading index finger.

  20. Auditory evoked potentials in children and adolescents with Down syndrome.

    Science.gov (United States)

    Gregory, Letícia; Rosa, Rafael F M; Zen, Paulo R G; Sleifer, Pricila

    2018-01-01

    Down syndrome, or trisomy 21, is the most common genetic alteration in humans. The syndrome presents with several features, including hearing loss and changes in the central nervous system, which may affect language development in children and lead to school difficulties. The present study aimed to investigate group differences in the central auditory system by long-latency auditory evoked potentials and cognitive potential. An assessment of 23 children and adolescents with Down syndrome was performed, and a control group composed of 43 children and adolescents without genetic and/or neurological changes was used for comparison. All children underwent evaluation with pure tone and vocal audiometry, acoustic immitance measures, long-latency auditory evoked potentials, and cognitive potential. Longer latencies of the waves were found in the Down syndrome group than the control group, without significant differences in amplitude, suggesting that individuals with Down syndrome have difficulty in discrimination and auditory memory. It is, therefore, important to stimulate and monitor these children in order to enable adequate development and improve their life quality. We also emphasize the importance of the application of auditory evoked potentials in clinical practice, in order to contribute to the early diagnosis of hearing alterations and the development of more research in this area. © 2017 Wiley Periodicals, Inc.

  1. ROLE OF MENINGEAL MAST CELLS IN INTRATHECAL MORPHINE EVOKED GRANULOMA FORMATION

    Science.gov (United States)

    Yaksh, Tony L.; Allen, Jeffery W.; Veesart, Samantha L.; Horais, Kjersti A; Malkmus, Shelle A.; Scadeng, Miriam; Steinauer, Joanne J.; Rossi, Steve S

    2013-01-01

    Background Intrathecal morphine forms granulomas that arise from the adjacent arachnoid membrane. We propose that these inflammatory cells exit the meningeal vasculature secondary to meningeal mast cell degranulation. Methods Three sets of experiments were accomplished in dogs. 1) Ex vivo Meningeal mast cell degranulation. Histamine release was measured ex vivo from canine dura incubated with opiates. 2) In vivo cutaneous mast cell degranulation. Flare areas on the dog abdomen were measured after subcutaneous opiates. 3) In vivo granuloma pharmacology. Dogs with lumbar intrathecal catheters received infusion of intrathecal saline or intrathecal morphine. Intrathecal morphine dogs received: i) No other treatment (Control); ii) Twice daily subcutaneous naltrexone; iii) Intrathecal co-infusion of cromolyn; or, iv) Twice daily subcutaneous cromolyn for the 24–28 day study course. Results 1) Morphine but not fentanyl evoked dural histamine release, which was blocked by cromolyn but not naloxone. 2) Wheal/flare was produced by subcutaneous morphine, methadone, hydromorphone, but not fentanyl, and was unaffected by naltrexone but prevented by cromolyn. 3) Granulomas occurred in all dogs receiving intrathecal morphine (15/15); subcutaneous naltrexone had no effect on granulomas (6/6), but was reduced by concurrent intrathecal cromolyn (0/5) or twice daily subcutaneous cromolyn (1 of 5). Conclusions The pharmacology of cutaneous/dural MC degranulation and intrathecal granulomas are comparable, not mediated by opioid receptors, and reduced by agents preventing MC degranulation. If an agent produces cutaneous MC degranulation at concentrations produced by intrathecal delivery, the agent may initiate granulomas. PMID:23426209

  2. Depolarization by K+ and glutamate activates different neurotransmitter release mechanisms in GABAergic neurons: vesicular versus non-vesicular release of GABA

    DEFF Research Database (Denmark)

    Belhage, B; Hansen, Gert Helge; Schousboe, A

    1993-01-01

    Neurotransmitter release and changes in the concentration of intracellular free calcium ([Ca++]i) were studied in cultured GABAergic cerebral cortical neurons, from mice, upon depolarization with either an unphysiologically high potassium concentration (55 mM) or the physiological excitatory...... neurotransmitter glutamate (100 microM). Both depolarizing stimuli exerted prompt increases in the release of preloaded [3H]GABA as well as in [Ca++]i. However, the basic properties of transmitter release and the increase in [Ca++]i under a variety of conditions were different during stimulation with K...... in nature whereas that induced by the neurotransmitter glutamate is not....

  3. Binaural interaction in auditory evoked potentials: Brainstem, middle- and long-latency components

    OpenAIRE

    McPherson, DL; Starr, A

    1993-01-01

    Binaural interaction occurs in the auditory evoked potentials when the sum of the monaural auditory evoked potentials are not equivalent to the binaural evoked auditory potentials. Binaural interaction of the early- (0-10 ms), middle- (10-50 ms) and long-latency (50-200 ms) auditory evoked potentials was studied in 17 normal young adults. For the early components, binaural interaction was maximal at 7.35 ms accounting for a reduction of 21% of the amplitude of the binaural evoked potentials. ...

  4. News/Press Releases

    Data.gov (United States)

    Office of Personnel Management — A press release, news release, media release, press statement is written communication directed at members of the news media for the purpose of announcing programs...

  5. Cell-attached recordings of responses evoked by photorelease of GABA in the immature cortical neurons

    Directory of Open Access Journals (Sweden)

    Marat eMinlebaev

    2013-05-01

    Full Text Available We present a novel non-invasive technique to measure the polarity of GABAergic responses based on cell-attached recordings of currents activated by laser-uncaging of GABA. For these recordings, a patch pipette was filled with a solution containing RuBi-GABA, and GABA was released from this complex by a laser beam conducted to the tip of the patch pipette via an optic fiber. In cell-attached recordings from neocortical and hippocampal neurons in postnatal days P2-5 rat brain slices in vitro, we found that laser-uncaging of GABA activates integral cell-attached currents mediated by tens of GABA(A channels. The initial response was inwardly directed, indicating a depolarizing response to GABA. The direction of the initial response was dependent on the pipette potential and analysis of its slope-voltage relationships revealed a depolarizing driving force of +11 mV for the currents through GABA channels. Initial depolarizing responses to GABA uncaging were inverted to hyperpolarizing in the presence of the NKCC1 blocker bumetanide. Current-voltage relationships of the currents evoked by Rubi-GABA uncaging using voltage-ramps at the peak of responses not only revealed a bumetanide-sensitive depolarizing reversal potential of the GABA(A receptor mediated responses, but also showed a strong voltage-dependent hysteresis. Upon desensitization of the uncaged-GABA response, current-voltage relationships of the currents through single GABA(A channels revealed depolarizing responses with the driving force values similar to those obtained for the initial response. Thus, cell-attached recordings of the responses evoked by local intrapipette GABA uncaging are suitable to assess the polarity of the GABA(A-Rs mediated signals in small cell compartments.

  6. Evidence against ATP being the inhibitory transmitter released by nonadrenergic noncholinergic nerves in the canine ileocolonic junction

    NARCIS (Netherlands)

    Boeckxstaens, G. E.; Pelckmans, P. A.; Rampart, M.; Verbeuren, T. J.; Herman, A. G.; van Maercke, Y. M.

    1990-01-01

    The nonadrenergic noncholinergic (NANC) relaxations in response to electrical stimulation and acetylcholine in the canine terminal ileum and ileocolonic junction were further characterized and the possible involvement of the putative NANC neurotransmitter ATP was investigated. During a

  7. Pharmacology of neurotransmitter release: measuring exocytosis.

    Science.gov (United States)

    Khvotchev, Mikhail; Kavalali, Ege T

    2008-01-01

    Neurotransmission in the nervous system is initiated at presynaptic terminals by fusion of synaptic vesicles with the plasma membrane and subsequent exocytic release of chemical transmitters. Currently, there are multiple methods to detect neurotransmitter release from nerve terminals, each with their own particular advantages and disadvantages. For instance, most commonly employed methods monitor actions of released chemical substances on postsynaptic receptors or artificial substrates such as carbon fibers. These methods are closest to the physiological setting because they have a rapid time resolution and they measure the action of the endogenous neurotransmitters rather than the signals emitted by exogenous probes. However, postsynaptic receptors only indirectly report neurotransmitter release in a form modified by the properties of receptors themselves, which are often nonlinear detectors of released substances. Alternatively, released chemical substances can be detected biochemically, albeit on a time scale slower than electrophysiological methods. In addition, in certain preparations, where presynaptic terminals are accessible to whole cell recording electrodes, fusion of vesicles with the plasma membrane can be monitored using capacitance measurements. In the last decade, in addition to electrophysiological and biochemical methods, several fluorescence imaging modalities have been introduced which report synaptic vesicle fusion, endocytosis, and recycling. These methods either take advantage of styryl dyes that can be loaded into recycling vesicles or exogenous expression of synaptic vesicle proteins tagged with a pH-sensitive GFP variant at regions facing the vesicle lumen. In this chapter, we will provide an overview of these methods with particular emphasis on their relative strengths and weaknesses and discuss the types of information one can obtain from them.

  8. Experimental endotoxemia in humans: analysis of cytokine release and coagulation, fibrinolytic, and complement pathways

    NARCIS (Netherlands)

    van Deventer, S. J.; Büller, H. R.; ten Cate, J. W.; Aarden, L. A.; Hack, C. E.; Sturk, A.

    1990-01-01

    Endotoxemia was evoked by bolus injection of Escherichia coli endotoxin (2 ng/kg body weight) in six healthy subjects to investigate the early kinetics of cytokine release in relation to the development of clinical and hematologic abnormalities frequently seen in gram-negative septicemia. The plasma

  9. Micro-miniature radio frequency transmitter for communication and tracking applications

    Energy Technology Data Exchange (ETDEWEB)

    Crutcher, R.I.; Emery, M.S.; Falter, K.G.; Nowlin, C.H. [Oak Ridge National Lab., TN (United States); Rochelle, J.M.; Clonts, L.G. [Univ. of Tennessee, Knoxville, TN (United States). Electrical Engineering Dept.

    1996-12-31

    A micro-miniature radio frequency (rf) transmitter has been developed and demonstrated by the Oak Ridge National Laboratory. The objective of the rf transmitter development was to maximize the transmission distance while drastically shrinking the overall transmitter size, including antenna. Based on analysis and testing, an application-specific integrated circuit (ASIC) with a 16-GHz gallium arsenide (GaAs) oscillator and integrated on-chip antenna was designed and fabricated using microwave monolithic integrated circuit (MMIC) technology. Details of the development and the results of various field tests will be discussed. The rf transmitter is applicable to covert surveillance and tracking scenarios due to its small size of 2.2 x 2.2 mm, including the antenna. Additionally, the 16-GHz frequency is well above the operational range of consumer-grade radio scanners, providing a degree of protection from unauthorized interception. Variations of the transmitter design have been demonstrated for tracking and tagging beacons, transmission of digital data, and transmission of real-time analog video from a surveillance camera. Preliminary laboratory measurements indicate adaptability to direct-sequence spread-spectrum transmission, providing a low probability of intercept and/or detection. Concepts related to law enforcement applications will be presented.

  10. The Effect of an Externally Attached Neutrally Buoyant Transmitter on Mortal Injury during Simulated Hydroturbine Passage

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Richard S.; Pflugrath, Brett D.; Carlson, Thomas J.; Deng, Zhiqun

    2012-02-03

    On their seaward migration, juvenile salmonids commonly pass hydroelectric dams. Fish passing through hydroturbines experience a rapid decrease in pressure as they pass by the turbine blade and the severity of this decompression can be highly variable. This rapid decrease in pressure can result in injuries such as swim bladder rupture, exophthalmia, and emboli and hemorrhaging in the fins and tissues. However, recent research indicates that the presence of a telemetry tag (acoustic, radio, inductive) implanted inside the coelom of a juvenile salmon increases the likelihood that the fish will be injured or die during turbine passage. Thus, previous research conducted using telemetry tags implanted into the coelom of fish may have been inaccurate. Thus, a new technique is needed to provide unbiased estimates of survival through turbines. This research provides an evaluation of the effectiveness of a neutrally buoyant externally attached acoustic transmitter. Both nontagged fish and fish tagged with a neutrally buoyant external transmitter were exposed to a range of rapid decompressions simulating turbine passage. Juvenile Chinook salmon tagged with a neutrally buoyant externally attached acoustic transmitter did not receive a higher degree of barotrauma than their nontagged counterparts. We suggest that future research include field-based comparisons of survival and behavior among fish tagged with a neutrally buoyant external transmitter and those internally implanted with transmitters.

  11. Preparation and characterization of high-transmittance AZO films using RF magnetron sputtering at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Jian [College of Materials and Chemical Engineering, Collaborative Innovation Center for Energy Equipment of Three Gorges Region, China Three Gorges University, Yichang 443002 (China); Sun, Yihua, E-mail: sunyihua316181@163.com [College of Materials and Chemical Engineering, Collaborative Innovation Center for Energy Equipment of Three Gorges Region, China Three Gorges University, Yichang 443002 (China); Lv, Xin; Li, Derong [Glass Industry Engineering Research Center of Hubei Province, Hubei Sanxia New Building Materials Co., Ltd., Dangyang 444105 (China); Fang, Liang; Wang, Hailin; Sun, Xiaohua; Huang, Caihua; Yu, Haizhou; Feng, Ping [College of Materials and Chemical Engineering, Collaborative Innovation Center for Energy Equipment of Three Gorges Region, China Three Gorges University, Yichang 443002 (China)

    2014-10-30

    Highlights: • We prepared the AZO thin films on soda-lime glass without the substrate heated. • High-transmittance AZO films had been obtained by RF magnetron sputtering using a ceramic target. • The minimum resistivity of 2.55 × 10{sup −3} Ω cm combined with highest transmittance of 91% was obtained at a sputtering power of 400 W. • The resistivity decreased and transmittance improved with the sputtering power increase. - Abstract: Aluminum-doped zinc oxide (AZO) thin films with 250 nm thickness had been prepared on soda-lime glass substrate without heated by RF magnetron sputtering using a ceramic target. The microstructure, surface morphology, electrical and optical properties of AZO thin films had been investigated by X-ray diffraction, scanning electron microscope, four-point probe method and optical transmission spectroscopy. The results indicated that all of the films obtained were polycrystalline with a hexagonal structure and oriented with the c-axis perpendicular to the substrate. The resistivity decreased and transmittance improved with the sputtering power increase. The minimum resistivity of 2.55 × 10{sup −3} Ω cm combined with highest transmittance of 91% was obtained at a sputtering power of 400 W. The optical bandgap at different sputtering power varied among 3.81–4.04 eV.

  12. Integration and test of high-speed transmitter electronics for free-space laser communications

    Science.gov (United States)

    Soni, Nitin J.; Lizanich, Paul J.

    1994-01-01

    The NASA Lewis Research Center in Cleveland, Ohio, has developed the electronics for a free-space, direct-detection laser communications system demonstration. Under the High-Speed Laser Integrated Terminal Electronics (Hi-LITE) Project, NASA Lewis has built a prototype full-duplex, dual-channel electronics transmitter and receiver operating at 325 megabit S per second (Mbps) per channel and using quaternary pulse-position modulation (QPPM). This paper describes the integration and testing of the transmitter portion for future application in free-space, direct-detection laser communications. A companion paper reviews the receiver portion of the prototype electronics. Minor modifications to the transmitter were made since the initial report on the entire system, and this paper addresses them. The digital electronics are implemented in gallium arsenide integrated circuits mounted on prototype boards. The fabrication and implementation issues related to these high-speed devices are discussed. The transmitter's test results are documented, and its functionality is verified by exercising all modes of operation. Various testing issues pertaining to high-speed circuits are addressed. A description of the transmitter electronics packaging concludes the paper.

  13. Capacitor-Shunted Transmitter for Power Reduction in Inductive-Coupling Clock Link

    Science.gov (United States)

    Kumar, Amit; Miura, Noriyuki; Kuroda, Tadahiro

    2008-04-01

    The importance of low-power and high-speed chip-to-chip communication between stacked chips is increasing in system in a package (SiP) systems. Wireless chip-to-chip communication is a promising technology that can increase the speed of inter-chip data transfer with very little area and power overhead. The wireless clock link in this scheme consumes more power than wireless data circuits. To reduce the overall power consumption we need to reduce the power consumed in the clock link of the circuit. In this paper we present a simple yet effective transmitter circuit, namely a capacitor-shunted transmitter, to reduce the power consumed in the clock transmitter. The simulation is carried out in spectre, and, to confirm the simulation result, a test chip is fabricated using Taiwan Semiconductor Manufacturing Company (TSMC) 0.18 µm complementary metal-oxide-semiconductor (CMOS). The simulation results and the test chip measurement results show that the power consumption of the clock transmitter circuit is reduced by 50% because of the capacitor-shunted transmitter circuit.

  14. Radio-transmitters have no impact on survival of pre-fledged American Woodcocks

    Science.gov (United States)

    Daly, Kyle O.; Andersen, David E.; Brininger, Wayne L.; Cooper, Thomas R.

    2015-01-01

    American Woodcocks (Scolopax minor) are a high priority species of conservation need across most of their breeding range due to long-term population declines. Survival of juveniles may be key to understanding these population declines, but there have been few direct estimates of juvenile woodcock survival rates, and no recent assessment of the possible effect of radio-tagging on juvenile survival. In 2011 and 2012, we radio-tagged 73 juvenile American Woodcocks in west-central Minnesota and compared survival rates of radio-tagged (N = 58) and non-radio-tagged (N = 82) juveniles during the period from hatching to fledging. We compared survival rates of juveniles with known fates and used logistic-exposure models to assess the potential impact of radio-transmitters on survival. We evaluated variables related to juvenile survival including age, hatch date, maximum and minimum temperature, precipitation, and year to assess the possible effects of radio-transmitters. The best-supported model of survival rate of juvenile American Woodcocks included the interaction of age and year and a negative effect of precipitation (β = −0.76, 85% CI: −1.08 to −0.43), but did not include a negative effect of transmitters. Our results suggest that radio-transmitters did not impact survival of juvenile American Woodcocks and that transmitters are a reliable tool for studying survival of juvenile American Woodcocks, and perhaps other precocial shorebirds.

  15. Fiber-Based, Trace-Gas, Laser Transmitter Technology Development for Space

    Science.gov (United States)

    Stephen, Mark; Yu, Anthony; Chen, Jeffrey; Nicholson, Jeffrey; Engin, Doruk; Mathason, Brian; Wu, Stewart; Allan, Graham; Hasselbrack, William; Gonzalez, Brayler; hide

    2015-01-01

    NASA’s Goddard Space Flight Center (GSFC) is working on maturing the technology readiness of a laser transmitter designed for use in atmospheric CO2 remote-sensing. GSFC has been developing an airplane-based CO2 lidar instrument over several years to demonstrate the efficacy of the instrumentation and measurement technique and to link the science models to the instrument performance. The ultimate goal is to make space-based satellite measurements with global coverage. In order to accomplish this, we must demonstrate the technology readiness and performance of the components as well as demonstrate the required power-scaling to make the link with the required signal-to-noise-ratio (SNR). To date, all the instrument components have been shown to have the required performance with the exception of the laser transmitter.In this program we are working on a fiber-based master oscillator power amplifier (MOPA) laser transmitter architecture where we will develop a ruggedized package and perform the relevant environmental tests to demonstrate TRL-6. In this paper we will review our transmitter architecture and progress on the performance and packaging of the laser transmitter.

  16. Solar energy transmittance of translucent samples. A comparison between large and small integrating sphere measurements

    Energy Technology Data Exchange (ETDEWEB)

    Chevalier, B.; Olive, F. [CSTB, Grenoble (France); Hutchins, M.G.; Squire, T. [School of Engineering, Oxford Brookes University, Headington, Gipsy Lane Campus, Oxford OX3 0BP (United Kingdom); Maccari, A. [ENEA, Rome (Italy); Oversloot, H. [TNO, Delft (Netherlands); Platzer, W. [ISES, Freiburg (Germany); Polato, P. [SSV, Murano (Italy); Roos, A. [Uppsala University, Uppsala (Sweden); Rosenfeld, J.L.J. [University of Wales, Cardiff (United Kingdom); Yoshimura, K. [NIRIN, Nagoya (Japan)

    1998-07-13

    Optical transmittance and reflectance of a translucent plastic PTFE film have been measured over the solar wavelength range using different integrating spheres. The same sample has been measured with small and large spheres and the total solar transmittance has been obtained from both broad band measurements and from integration of spectral data. The fact that the sum of reflectance and transmittance often exceeds 100% shows that all types of spheres tend to overestimate the transmittance of this highly scattering sample. This error can be attributed to the sphere geometry in combination with the light scattering properties of the sample, and unless proper correction of recorded data is carried out the error may be as large as 5-10%. Some specific errors are presented and an approximate correction procedure is suggested.These results show that there is a need for a transmittance standard which can be used to calibrate integrating spheres. Such a standard with negligible thickness would be especially useful for measurements with large, broadband integrating spheres, but would also be helpful for the correct handling of data from small spectral instruments

  17. Heat treatment effect on erosion behavior of poly(methylmethacrylate) for optical transmittance efficiency

    Science.gov (United States)

    Çoban, Onur

    2014-10-01

    Influence of heat treatment on optical transmittance of poly(methyl methacrylate) (PMMA) samples was investigated under solid particle erosion. Heat treatment was employed at 85 °C for 1, 2 and 3 h. Effect of heat treatment on physical, chemical, mechanical and thermal properties of PMMA samples was investigated by differential scanning calorimeter (DSC), thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) spectroscopy, Vickers microhardness measurement methods. After these analysis, both pristine and heat treated PMMA samples were eroded at 15°, 30°, 45°, 60°, 75° and 90° impingement angles. Then, optical transmittance of all eroded PMMA samples was inspected by a UV-Vis spectrometer. Scanning electron microscopy (SEM) was used to explain the erosion mechanisms and to compare the roughness and optical transmittance of eroded PMMA surfaces. Heat treatment under glass transition temperature of PMMA increased the Tg and hardness values. According to erosion test results, both pristine and heat treated PMMA samples were showed ductile erosion behavior. However; maximum and minimum optical transmittance values of eroded pristine PMMA samples were obtained for the angles of 15° and 90°, respectively. A positive effect of heat treatment on optical transmittance of PMMA was obtained for all impingement angles, but most pronounced effect was seen for 15°.

  18. Echinacoside Inhibits Glutamate Release by Suppressing Voltage-Dependent Ca2+ Entry and Protein Kinase C in Rat Cerebrocortical Nerve Terminals

    Directory of Open Access Journals (Sweden)

    Cheng Wei Lu

    2016-06-01

    Full Text Available The glutamatergic system may be involved in the effects of neuroprotectant therapies. Echinacoside, a phenylethanoid glycoside extracted from the medicinal Chinese herb Herba Cistanche, has neuroprotective effects. This study investigated the effects of echinacoside on 4-aminopyridine-evoked glutamate release in rat cerebrocortical nerve terminals (synaptosomes. Echinacoside inhibited Ca2+-dependent, but not Ca2+-independent, 4-aminopyridine-evoked glutamate release in a concentration-dependent manner. Echinacoside also reduced the 4-aminopyridine-evoked increase in cytoplasmic free Ca2+ concentration but did not alter the synaptosomal membrane potential. The inhibitory effect of echinacoside on 4-aminopyridine-evoked glutamate release was prevented by ω-conotoxin MVIIC, a wide-spectrum blocker of Cav2.2 (N-type and Cav2.1 (P/Q-type channels, but was insensitive to the intracellular Ca2+ release-inhibitors dantrolene and 7-chloro-5-(2-chloropheny-1,5-dihydro-4,1-benzothiazepin-2(3H-one (CGP37157. Furthermore, echinacoside decreased the 4-aminopyridine-induced phosphorylation of protein kinase C, and protein kinase C inhibitors abolished the effect of echinacoside on glutamate release. According to these results, we suggest that the inhibitory effect of echinacoside on evoked glutamate release is associated with reduced voltage-dependent Ca2+ entry and subsequent suppression of protein kinase C activity.

  19. Inhibition of serotonin release by bombesin-like peptides in rat hypothalamus in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Saporito, M.S.; Warwick, R.O. Jr.

    1989-01-01

    We investigated the activity of bombesin (BN), neuromedin-C (NM-C) and neuromedin-B (NM-B) on serotonin (5-HT) release and reuptake in rat hypothalamus (HYP) in vitro. BN and NM-C but not NM-B decreased K/sup +/ evoked /sup 3/H-5-HT release from superfused HYP slices by 25%. Bacitracin, a nonspecific peptidase inhibitor, reversed the inhibitory effect of BN on K/sup +/ evoked /sup 3/H-5-HT release. Phosphoramidon (PAN, 10 /mu/M) an endopeptidase 24.11 inhibitor, abolished the inhibitory effect of BN, but not NM-C, on K/sup +/ evoked /sup 3/H-5-HT release. The peptidyl dipeptidase A inhibitor enalaprilat (ENP, 10 /mu/M), enhanced both BN and NM-C inhibition of /sup 3/H-5-HT release. Bestatin (BST, 10 /mu/M) had no effect on BN or NM-C inhibitory activity on /sup 3/H-5-HT release. Neither BN, NM-C nor NM-B affected reuptake of /sup 3/H-5-HT into HYP synaptosomes alone or in combination with any of the peptidase inhibitors, nor did these peptides alter the ability of fluoxetine to inhibit /sup 3/H-5-HT uptake.

  20. Amino acid neurotransmitter release and learning: a study of visual imprinting.

    Science.gov (United States)

    Meredith, R M; McCabe, B J; Kendrick, K M; Horn, G

    2004-01-01

    The intermediate and medial part of the hyperstriatum ventrale (IMHV) is an area of the domestic chick forebrain that stores information acquired through the learning process of imprinting. The effects of visual imprinting on the release of the amino acids aspartate, arginine, citrulline, gamma-aminobutyric acid (GABA), glutamate, glycine and taurine from the left and right IMHVs in vitro were measured at 3.5, 10 and 24 h after training. Chicks were exposed to an imprinting stimulus for 1 h, their preferences measured 10 min afterward and a preference score calculated as a measure of the strength of learning. Potassium stimulation was used to evoke amino acid release from the IMHVs of trained and untrained chicks in the presence and absence of extracellular Ca2+. Ca2+-dependent, K+-evoked release of glutamate was significantly (34.4%) higher in trained than in untrained chicks. This effect was not influenced by time after training or by side (left or right IMHV). Training influenced the evoked release of GABA and taurine from the left IMHV at both 3.5 and 10 h. The training effects at the two times were statistically homogeneous so data (imprinting stimulus glutamatergic excitatory transmission in IMHV is enhanced, and remains enhanced for at least 24 h. In contrast, the learning-related elevations in taurine and GABA release are not sustained over this period. The change in GABA release may reflect a transient increase in inhibitory transmission in the left IMHV. Copyright 2004 IBRO

  1. Differential presynaptic effects of hexachlorocyclohexane isomers on noradrenaline release in cerebral cortex

    Energy Technology Data Exchange (ETDEWEB)

    Cristofol, R.M.; Rodriguez-Farre, E. (Consejo Superior de Investigaciones Cientificas, Barcelona (Spain))

    1991-01-01

    To investigate presynaptic effects of hexachlorocyclohexane (HCH) isomers, the release of noradrenaline (NA) in brain tissue was analyzed using rat cerebral cortical slices preloaded with ({sup 3}H)-NA. {gamma}-HCH (lindane) 50 {mu}M significantly enhanced the ({sup 3}H)-NA release evoked by 15-25 mM K{sup +}. {alpha}- and {beta}-HCH did not produce any significant effect on K{sup +}-evoked ({sup 3}H)-NA release. {delta}-HCH induced a significant decrease of the 25 mM K{sup +}-evoked release of ({sup 3}H)-NA. The effect of the {gamma}- and {delta}-HCH isomers on the presynaptic action of the {alpha}{sub 2}-agonist clonidine and the {alpha}{sub 2}-antagonist yohimbine was also studied. The presynaptic inhibitory effect of clonidine and the stimulatory effect of yohimbine on ({sup 3}H)-NA release was attenuated by lindane and {delta}-HCH, respectively. These results are consistent with a presynaptic action of the HCH isomers on noradrenergic release processes.

  2. Cortical modulation of short-latency TMS-evoked potentials

    Directory of Open Access Journals (Sweden)

    Domenica eVeniero

    2013-01-01

    Full Text Available Transcranial magnetic stimulation - electroencephalogram (TMS-EEG co-registration offers the opportunity to test reactivity of brain areas across distinct conditions through TMS-evoked potentials (TEPs. Several TEPs have been described, their functional meaning being largely unknown. In particular, short-latency potentials peaking at 5 (P5 and 8 (N8 ms after the TMS pulse have been recently described, but because of their huge amplitude, the problem of whether their origin is cortical or not has been opened. To gain information about these components, we employed a protocol that modulates primary motor cortex excitability (MI through an exclusively cortical phenomena: low frequency stimulation of premotor area (PMC. TMS was applied simultaneously with EEG recording from 70 electrodes. Amplitude of TEPs evoked by 200 single-pulses TMS delivered over MI at 110% of resting motor threshold was measured before and after applying 900 TMS conditioning stimuli to left premotor cortex with 1 Hz repetition rate. Single subject analyses showed reduction in TEPs amplitude after PMC conditioning in a sample of participants and increase in TEPs amplitude in two subjects. No effects were found on corticospinal excitability as recorded by motor evoked potentials (MEPs. Furthermore, correlation analysis showed an inverse relation between the effects of the conditioning protocol on P5-N8 complex amplitude and MEPs amplitude. Because the effects of the used protocol have been ascribed to a cortical interaction between premotor area and MI, we suggest that despite the sign of P5-N8 amplitude modulation is not consistent across participant, this modulation could indicate, at least in part, their cortical origin. We conclude that with an accurate experimental procedure early-latency components can be used to evaluate the reactivity of the stimulated cortex.

  3. The neonatal development of the light flash visual evoked potential.

    Science.gov (United States)

    Kraemer, M; Abrahamsson, M; Sjöström, A

    1999-01-01

    To follow visual development longitudinally in the normal neonate using the flash visual evoked potential (VEP) and to find indications for a relationship between potential development and visual development. Twenty healthy infants, born at term, were included in the study. Flash and patterned flash VEPs were used. The first VEP was recorded the day of birth or just postnatally, and succeeding recordings were performed the following weeks and months. The data revealed different types of VEP in the neonatal period suggesting great variability in visual function on the day of birth. In the early development a potential of long latency and duration preceded the development of a more compound potential of shorter latency. The two types of responses seemed to coalesce during early development; the first late response was attenuated and was eventually integrated in the more mature VEP. At approximately five weeks of age changes in the VEP were simultaneous with the development of responsive smiling and another visual behaviour of the infants. The results showed many similarities between the VEP development in infants and in immature animals. In developing animals geniculo-cortical and extra-geniculate visual afferent pathways evoke two types of VEPs similar to those recorded in the present study. The early responses were also similar to previous recordings from children with lesions in the geniculo-striatal pathway or primary cortex. Our interpretation of the results was that the human VEP also consists of responses evoked by afferents running both in geniculo-cortical and extra-geniculate pathways and that the two types of responses could be separated in the VEP in the neonatal period. These findings are important for our understanding of conditions with a delay in visual maturation, for example intracranial haemorrhages, hydrocephalus, pre/dys-maturity and 'idiopathic' delayed visual maturation.

  4. Marine spawning sites of perch Perca fluviatilis revealed by oviduct-inserted acoustic transmitters

    DEFF Research Database (Denmark)

    Skovrind, Mikkel; Christensen, Emil A.F.; Carl, Henrik

    2013-01-01

    In the 1970s, a flood-protection system dramatically changed a large part of the coastal environment of Køge Bugt, a bay in the western Baltic Sea, from open coast to a brackish lagoon habitat. An anadromous stock of European perch Perca fluviatilis seems to have benefitted from this change...... a strong proof of concept of oviduct-inserted acoustic transmitters in brackish and marine fish spawning studies. The transmitter expulsions were validated using an egg map, which was based on visual observations of perch egg-strands, and 11 of the 12 expulsed transmitters (92%) were located in areas...... with eggs. Many fish spawned in the brackish water with salinities up to 9.6 PSU. These salinities are higher than those previously observed for European perch spawning in the wild, and call for further investigations of salinity tolerance in perch eggs...

  5. In Situ Thermal Transmittance Measurements for Investigating Differences between Wall Models and Actual Building Performance

    Directory of Open Access Journals (Sweden)

    Luca Evangelisti

    2015-08-01

    Full Text Available An accurate assessment of a building’s wall performance, defined through the thermal transmittance, is essential to compute the annual energy consumption. Analyzing opaque surfaces, the heat transfer across walls can be modeled by an electro-thermal analogy, based on resistors series, crossed by a one-dimensional heat flow. This analogy is well established and it refers to stratigraphy composed of homogeneous materials. When dealing with inhomogeneous materials, possibly including hollow bricks, the wall’s thermal transmittance is evaluated by means of an effective conductance. However, in order to verify the theoretical models effectiveness, a comparison with in situ measurements is needed. In this paper, three building walls characterized by different stratigraphy have been analyzed; by employing a heat flow meter investigation. Measurements results and estimated thermal transmittance values—calculated applying the standard UNI EN ISO 6946—have been compared.

  6. Transmitter and Translating Receiver Design For 64-ary Pulse Position Modulation (PPM)

    Energy Technology Data Exchange (ETDEWEB)

    Mendez, A J; Hernandez, V J; Gagliardi, R M; Bennett, C V

    2010-01-20

    This paper explores the architecture and design of an optically-implemented 64-ary PPM transmitter and direct-translating receiver that effectively translates incoming electrically-generated bit streams into optical PPM symbols (and vice-versa) at > 1 Gb/s data rates. The PPM transmitter is a cascade of optical switches operating at the frame rate. A corresponding receiver design is more difficult to architect and implement, since increasing data rates lead to correspondingly shorter decision times (slot times and frame times). We describe a solution in the form of a time-to-space mapping arrayed receiver that performs a translating algorithm represented as a code map. The technique for generating the code map is described, and the implementation of the receiver as a planar lightwave circuit is given. The techniques for implementing the transmitter and receiver can be generalized for any case of M-ary PPM.

  7. Optimal position of the transmitter coil for wireless power transfer to the implantable device.

    Science.gov (United States)

    Jinghui Jian; Stanaćević, Milutin

    2014-01-01

    The maximum deliverable power through inductive link to the implantable device is limited by the tissue exposure to the electromagnetic field radiation. By moving away the transmitter coil from the body, the maximum deliverable power is increased as the magnitude of the electrical field at the interface with the body is kept constant. We demonstrate that the optimal distance between the transmitter coil and the body is on the order of 1 cm when the current of the transmitter coil is limited to 1 A. We also confirm that the conditions on the optimal frequency of the power transmission and the topology of the transmission coil remain the same as if the coil was directly adjacent to the body.

  8. A self-oscillating detuning-insensitive class-E transmitter for implantable microsystems.

    Science.gov (United States)

    Ziaie, B; Rose, S C; Nardin, M D; Najafi, K

    2001-03-01

    This paper describes a low-cost, self-oscillating, detuning-in-sensitive, class-E driver for transcutaneous power and data transmission to implantable microsystems. A voltage feedback scheme using a fast comparator for zero-crossing detection and a CMOS start-up circuit were used to stabilize the class-E operation for various transmitter coil inductance values. This technique solves the common problem of mismatch between the switching frequency of the driving device and the resonant frequency of the load network, which can cause excessive power loss and damage to the active device. Data is transmitted by AM modulation of the carrier through switching the power supply between two levels. The transmitter uses a 9-V supply, consumes 212 mA, operates at 3.9 MHz, and has an efficiency of 71%. The efficiency is stable (Biomedical microsystems, class-E transmitter, implantable electronics, inductive powering, transcutaneous links.

  9. Determination of Aluminium Content in Aluminium Hydroxide Formulation by FT-NIR Transmittance Spectroscopy

    DEFF Research Database (Denmark)

    Lai, Xuxin; Zheng, Yiwu; Søndergaard, Ib

    2007-01-01

    A method for determining the aluminium content of an aluminium hydroxide suspension using near infrared (NIR) transmittance spectroscopy has been developed. Inductively coupled plasma-atomic emission spectroscopy (ICP-AES) was used as reference method. The factors influencing the NIR analysis...... by NIR transmission each on five different days, with total of 175 spectra used for the calibration set. The multivariate data analysis technique partial least square regression (PLSR) was applied to build the calibration model. Six batches of aluminium hydroxide samples were used for the test set. ICP......-AES and NIR transmittance spectroscopy exhibit comparable precision and accuracy. The NIR method provides several advantages: no complicated sample preparation; easy to operate; fast and non-destructive. In conclusion, NIR transmittance spectroscopy can be an alternative analytical method for determining...

  10. Standard Test Method for Solar Photometric Transmittance of Sheet Materials Using Sunlight

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1996-01-01

    1.1 This test method covers the measurement of solar photometric transmittance of materials in sheet form. Solar photometric transmittance is measured using a photometer (illuminance meter) in an enclosure with the sun and sky as the source of radiation. The enclosure and method of test is specified in Test Method E 1175 (or Test Method E 1084). 1.2 The purpose of this test method is to specify a photometric sensor to be used with the procedure for measuring the solar photometric transmittance of sheet materials containing inhomogeneities in their optical properties. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  11. Design of ultrasonic transmitters with defined frequency characteristics for wireless pressure sensing in injection molding.

    Science.gov (United States)

    Zhang, Li; Theurer, Charles B; Gao, Robert X; Kazmer, David O

    2005-08-01

    This paper describes a new mechanical wireless data transmission technique using ultrasonic waves as the information carrier for on-line injection mold cavity pressure measurement. Ultrasonic transmitters with specific frequency characteristics were designed, modeled, simulated, and prototyped for pressure data retrieval from an enclosed machine environment, as well as for sensor identification in a sensor matrix configuration. The effects of the front layer and bonding layer of the transmitter on the overall sensor frequency characteristics were investigated, using an equivalent circuit model. The optimal layer thickness was determined for the design of transmitters with specific dominant resonant frequency and narrow bandwidth. Experimental results were in good agreement with the analysis, thus confirming the design approach.

  12. Standard Test Methods for Solar Energy Transmittance and Reflectance (Terrestrial) of Sheet Materials

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1971-01-01

    1.1 These test methods cover the measurement of solar energy transmittance and reflectance (terrestrial) of materials in sheet form. Method A, using a spectrophotometer, is applicable for both transmittance and reflectance and is the referee method. Method B is applicable only for measurement of transmittance using a pyranometer in an enclosure and the sun as the energy source. Specimens for Method A are limited in size by the geometry of the spectrophotometer while Method B requires a specimen 0.61 m2 (2 ft2). For the materials studied by the drafting task group, both test methods give essentially equivalent results. 1.2 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  13. Microscopically crumpled indium-tin-oxide thin films as compliant electrodes with tunable transmittance

    Energy Technology Data Exchange (ETDEWEB)

    Ong, Hui-Yng [School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore 639798 (Singapore); School of Engineering, Nanyang Polytechnic, Singapore 569830 (Singapore); Shrestha, Milan; Lau, Gih-Keong, E-mail: mgklau@ntu.edu.sg [School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore 639798 (Singapore)

    2015-09-28

    Indium-tin-oxide (ITO) thin films are perceived to be stiff and brittle. This letter reports that crumpled ITO thin films on adhesive poly-acrylate dielectric elastomer can make compliant electrodes, sustaining compression of up to 25% × 25% equi-biaxial strain and unfolding. Its optical transmittance reduces with crumpling, but restored with unfolding. A dielectric elastomer actuator (DEA) using the 14.2% × 14.2% initially crumpled ITO thin-film electrodes is electrically activated to produce a 37% areal strain. Such electric unfolding turns the translucent DEA to be transparent, with transmittance increased from 39.14% to 52.08%. This transmittance tunability promises to make a low-cost smart privacy window.

  14. Methods of Phase and Power Control in Magnetron Transmitters for Superconducting Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Kazadevich, G. [MUONS Inc., Batavia; Johnson, R. [MUONS Inc., Batavia; Neubauer, M. [MUONS Inc., Batavia; Lebedev, V. [Fermilab; Schappert, W. [Fermilab; Yakovlev, V. [Fermilab

    2017-05-01

    Various methods of phase and power control in magnetron RF sources of superconducting accelerators intended for ADS-class projects were recently developed and studied with conventional 2.45 GHz, 1 kW, CW magnetrons operating in pulsed and CW regimes. Magnetron transmitters excited by a resonant (injection-locking) phasemodulated signal can provide phase and power control with the rates required for precise stabilization of phase and amplitude of the accelerating field in Superconducting RF (SRF) cavities of the intensity-frontier accelerators. An innovative technique that can significantly increase the magnetron transmitter efficiency at the widerange power control required for superconducting accelerators was developed and verified with the 2.45 GHz magnetrons operating in CW and pulsed regimes. High efficiency magnetron transmitters of this type can significantly reduce the capital and operation costs of the ADSclass accelerator projects.

  15. Light transmittance of fiber posts following various surface treatments: A preliminary study.

    Science.gov (United States)

    Cekic-Nagas, Isil; Ergun, Gulfem; Egilmez, Ferhan

    2016-01-01

    The objective of this study was to compare the light transmittance of fiber posts following application of various surface treatments. Fiber post specimens (Snowpost red size #14) were tested (n = 7). The fiber posts were divided into five groups according to the application of surface treatments: Group 1: No surface treatment; Group 2: Etched with hydrofluoric acid (HF) + silane application; Group 3: Airborne-particle abraded with 110 μm Al2O3; Group 4: Irradiated with erbium: Yttrium-aluminum-garnet laser; Group 5: Airborne-particle abraded with 110 μm Al2O3 + silane application. The light transmittance of the specimens was compared using a spectrophotometer. Statistical significance was determined using one-way analysis of variance (ANOVA) (α = 0.05). One-way ANOVA revealed that surface treatment had significant effects on light transmittance of posts (P fiber posts.

  16. Linear thermal transmittance of the assembly of the glazing and the frame in windows

    DEFF Research Database (Denmark)

    Svendsen, Svend; Laustsen, Jacob Birck; Kragh, Jesper

    2005-01-01

    The thermal transmittance or U-value of windows can be found by calculation according to the standards EN ISO 10077-1/2 (CEN,2000). The window U-value is calculated from the U-value of the glazing and the frame as well as the linear thermal transmittance of the assembly of the glazing and the frame....... The U-value of the glazing and the frame can be calculated separately while the calculation of the linear thermal transmittance includes the design of the edge construction of the glazing unit but also the design of the frame and the glazing unit. The edge construction of glazing units is made up...... of a spacer profile and a sealing. The spacer profile is typically made of metal and acts as a significant thermal bridge. Spacer profiles with improved thermal characteristics have been developed and are being introduced as ‘warm edge’. They are typically based on thin layers of stainless steel...

  17. High-energy, 2µm laser transmitter for coherent wind LIDAR

    Science.gov (United States)

    Singh, Upendra N.; Yu, Jirong; Kavaya, Michael J.; Koch, Grady J.

    2017-11-01

    A coherent Doppler lidar at 2μm wavelength has been built with higher output energy (300 mJ) than previously available. The laser transmitter is based on the solid-state Ho:Tm:LuLiF, a NASA Langley Research Center invented laser material for higher extraction efficiency. This diode pumped injection seeded MOPA has a transform limited line width and diffraction limited beam quality. NASA Langley Research Center is developing coherent wind lidar transmitter technology at eye-safe wavelength for satellite-based observation of wind on a global scale. The ability to profile wind is a key measurement for understanding and predicting atmospheric dynamics and is a critical measurement for improving weather forecasting and climate modeling. We would describe the development and performance of an engineering hardened 2μm laser transmitter for coherent Doppler wind measurement from ground/aircraft/space platform.

  18. NOVEL TECHNIQUE OF POWER CONTROL IN MAGNETRON TRANSMITTERS FOR INTENSE ACCELERATORS

    Energy Technology Data Exchange (ETDEWEB)

    Kazakevich, G. [MUONS Inc., Batavia; Johnson, R. [MUONS Inc., Batavia; Neubauer, M.; Lebedev, V. [Fermilab; Schappert, W. [Fermilab; Yakovlev, V. [Fermilab

    2016-10-21

    A novel concept of a high-power magnetron transmitter allowing dynamic phase and power control at the frequency of locking signal is proposed. The transmitter compensating parasitic phase and amplitude modulations inherent in Superconducting RF (SRF) cavities within closed feedback loops is intended for powering of the intensity-frontier superconducting accelerators. The con- cept uses magnetrons driven by a sufficient resonant (in- jection-locking) signal and fed by the voltage which can be below the threshold of self-excitation. This provides an extended range of power control in a single magnetron at highest efficiency minimizing the cost of RF power unit and the operation cost. Proof-of-principle of the proposed concept demonstrated in pulsed and CW regimes with 2.45 GHz, 1kW magnetrons is discussed here. A conceptual scheme of the high-power transmitter allowing the dynamic wide-band phase and y power controls is presented and discussed.

  19. Human auditory evoked potentials. I - Evaluation of components

    Science.gov (United States)

    Picton, T. W.; Hillyard, S. A.; Krausz, H. I.; Galambos, R.

    1974-01-01

    Fifteen distinct components can be identified in the scalp recorded average evoked potential to an abrupt auditory stimulus. The early components occurring in the first 8 msec after a stimulus represent the activation of the cochlea and the auditory nuclei of the brainstem. The middle latency components occurring between 8 and 50 msec after the stimulus probably represent activation of both auditory thalamus and cortex but can be seriously contaminated by concurrent scalp muscle reflex potentials. The longer latency components occurring between 50 and 300 msec after the stimulus are maximally recorded over fronto-central scalp regions and seem to represent widespread activation of frontal cortex.

  20. The division of attention and the human auditory evoked potential

    Science.gov (United States)

    Hink, R. F.; Van Voorhis, S. T.; Hillyard, S. A.; Smith, T. S.

    1977-01-01

    The sensitivity of the scalp-recorded, auditory evoked potential to selective attention was examined while subjects responded to stimuli presented to one ear (focused attention) and to both ears (divided attention). The amplitude of the N1 component was found to be largest to stimuli in the ear upon which attention was to be focused, smallest to stimuli in the ear to be ignored, and intermediate to stimuli in both ears when attention was divided. The results are interpreted as supporting a capacity model of attention.

  1. Brain stem auditory evoked responses in human infants and adults

    Science.gov (United States)

    Hecox, K.; Galambos, R.

    1974-01-01

    Brain stem evoked potentials were recorded by conventional scalp electrodes in infants (3 weeks to 3 years of age) and adults. The latency of one of the major response components (wave V) is shown to be a function both of click intensity and the age of the subject; this latency at a given signal strength shortens postnatally to reach the adult value (about 6 msec) by 12 to 18 months of age. The demonstrated reliability and limited variability of these brain stem electrophysiological responses provide the basis for an optimistic estimate of their usefulness as an objective method for assessing hearing in infants and adults.

  2. The Electrically Evoked Compound Action Potential: From Laboratory to Clinic.

    Science.gov (United States)

    He, Shuman; Teagle, Holly F B; Buchman, Craig A

    2017-01-01

    The electrically evoked compound action potential (eCAP) represents the synchronous firing of a population of electrically stimulated auditory nerve fibers. It can be directly recorded on a surgically exposed nerve trunk in animals or from an intra-cochlear electrode of a cochlear implant. In the past two decades, the eCAP has been widely recorded in both animals and clinical patient populations using different testing paradigms. This paper provides an overview of recording methodologies and response characteristics of the eCAP, as well as its potential applications in research and clinical situations. Relevant studies are reviewed and implications for clinicians are discussed.

  3. Temporal suppression and augmentation of click-evoked otoacoustic emissions

    DEFF Research Database (Denmark)

    Verhulst, Sarah; Harte, James; Dau, Torsten

    2008-01-01

    This study investigates and models temporal suppression of click-evoked otoacoustic emissions (CEOAEs). This suppression-effect is created when a suppressor-click is presented close in time to a test-click. The analysis was carried out for short time-frames of short- and long-latency CEOAEs...... suppression is present in all CEOAEs for inter-click intervals (ICIs) less than 8 ms. The long-latency CEOAEs showed augmentation (i.e., negative suppression) for ICIs of 6-7 ms which was not reported for the short-latency CEOAE at these ICIs. A phenomenological approach is adopted here to explain both...

  4. Estimation of evoked potentials using total least squares prony technique.

    Science.gov (United States)

    Akkin, T; Saliu, S

    1998-09-01

    The authors investigate the applicability of Prony modelling to the estimation of evoked potentials. Four types of total least squares (TLS) model are considered and their optimal parameters are defined based on ten visual averaged EPs. Simulations with various signal and noise characteristics show that the TLS-Prony estimation is superior to averaging for two of the models, namely the unconstrained and the stable models. Application of the TLS-Prony estimator as a post-processor to moderate averaging allows a reduction in the number of responses averaged, or equivalently of recording time, by a factor of two.

  5. Neuronal Rac1 is required for learning-evoked neurogenesis

    DEFF Research Database (Denmark)

    Haditsch, Ursula; Anderson, Matthew P; Freewoman, Julia

    2013-01-01

    Hippocampus-dependent learning and memory relies on synaptic plasticity as well as network adaptations provided by the addition of adult-born neurons. We have previously shown that activity-induced intracellular signaling through the Rho family small GTPase Rac1 is necessary in forebrain projection...... neurons for normal synaptic plasticity in vivo, and here we show that selective loss of neuronal Rac1 also impairs the learning-evoked increase in neurogenesis in the adult mouse hippocampus. Earlier work has indicated that experience elevates the abundance of adult-born neurons in the hippocampus...

  6. Transmittance of semitransparent windows with absorbing cap-shaped droplets condensed on their backside

    Science.gov (United States)

    Zhu, Keyong; Pilon, Laurent

    2017-11-01

    This study aims to investigate systematically light transfer through semitransparent windows with absorbing cap-shaped droplets condensed on their backside as encountered in greenhouses, solar desalination plants, photobioreactors and covered raceway ponds. The Monte Carlo ray-tracing method was used to predict the normal-hemispherical transmittance, reflectance, and normal absorptance accounting for reflection and refraction at the air/droplet, droplet/window, and window/air interfaces and absorption in both the droplets and the window. The droplets were monodisperse or polydisperse and arranged either in an ordered hexagonal pattern or randomly distributed on the backside with droplet contact angle θc ranging between 0 and 180° The normal-hemispherical transmittance was found to be independent of the spatial distribution of droplets. However, it decreased with increasing droplet diameter and polydispersity. The normal-hemispherical transmittance featured four distinct optical regimes for semitransparent window supporting nonabsorbing droplets. These optical regimes were defined based on contact angle and critical angle for internal reflection at the droplet/air interface. However, for strongly absorbing droplets, the normal-hemispherical transmittance (i) decreased monotonously with increasing contact angle for θc absorption index kd, droplet mean diameter dm, and contact angle θc for θc ≥ 90° Analytical expressions for the normal-hemispherical transmittance were provided in the asymptotic cases when (1) the window was absorbing but the droplets were nonabsorbing with any contact angles θc, and (2) the droplets were strongly absorbing with contact angle θc >90° Finally, the spectral normal-hemispherical transmittance of a 3 mm-thick glass window supporting condensed water droplets for wavelength between 0.4 and 5 μm was predicted and discussed in light of the earlier parametric study and asymptotic behavior.

  7. Examination of an Optical Transmittance Test for Photovoltaic Encapsulation Materials (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Miller, D.; Bengoechea, J.; Bokria, J.; Kohl, M.; Powell, N. E.; Smith, M. E.; White, M. D.; Wilson, H. R.; Wohlgemuth, J. H.

    2013-09-01

    The optical transmittance of encapsulation materials is a key characteristic for their use in photovoltaic (PV) modules. Changes in transmittance with time in the field affect module performance, which may impact product warranties. Transmittance is important in product development, module manufacturing, and field power production (both immediate and long-term). Therefore, an international standard (IEC 62788-1-4) has recently been proposed by the Encapsulation Task-Group within the Working Group 2 (WG2) of the International Electrotechnical Commission (IEC) Technical Committee 82 (TC82) for the quantification of the optical performance of PV encapsulation materials. Existing standards, such as ASTM E903, are general and more appropriately applied to concentrated solar power than to PV. Starting from the optical transmittance measurement, the solar-weighted transmittance of photon irradiance, yellowness index (which may be used in aging studies to assess durability), and ultraviolet (UV) cut-off wavelength may all be determined using the proposed standard. The details of the proposed test are described. The results of a round-robin experiment (for five materials) conducted at seven laboratories to validate the test procedure using representative materials are also presented. For example, the Encapsulation Group actively explored the measurement requirements (wavelength range and resolution), the requirements for the spectrophotometer (including the integrating sphere and instrument accessories, such as a depolarizer), specimen requirements (choice of glass-superstrate and -substrate), and data analysis (relative to the light that may be used in the PV application). The round-robin experiment identified both intra- and inter-laboratory instrument precision and bias for five encapsulation materials (encompassing a range of transmittance and haze-formation characteristics).

  8. Research on control technology of hardware parallelism for marine controlled source electromagnetic transmitter

    Science.gov (United States)

    Wang, Meng; Deng, Ming; Luo, Xianhu; Zhao, Qingxian; Chen, Kai; Jing, Jianen

    2018-02-01

    The marine controlled source electromagnetic (CSEM) method has been recognized as an effective exploration method of shallow hydrocarbons around the world. We developed our own underwater marine CSEM transmitter that consisted of many functional modules with various response times. We previously adopted a centralized software-control technology to design the transmitter circuit topological structure. That structure probably generated a control disorder or malfunction. These undesirable conditions could lead to repeated recovery and deployment of the transmitter, which not only consumed time but also affected data continuity and establishment of stable and continuous CSEM field. We developed an instrument design concept named ‘control technology of hardware parallelism’. In this design, a noteworthy innovation of our new technology is to solve the above-mentioned problems at the physical and fundamental levels. We used several self-contained control-units to simultaneously accomplish the predetermined functions of the transmitter. The new solution relies on two technologies: multi-core embedded technology and multi-channel parallel optical-fiber data transmission technology. The first technology depends on many independent microcontrollers. Every microcontroller is only used to achieve a customized function. The second one relies on several multiple optical-fiber transmission channels realized by a complex programmable logic device and two optical-fiber conversion devices, which are used to establish a communication link between the shipboard monitoring and control-unit and underwater transmitter. We have conducted some marine experiments to verify the reliability and stability of the new method. In particular, the new technology used in the transmitter system could help us obtain more useful measured data in a limited time, improve real-time efficiency, and support the establishment of a stable CSEM field.

  9. The spatial distribution features of three Alpha transmitter signals at the topside ionosphere

    Science.gov (United States)

    Zhang, X.; Zhao, S. F.; Ruzhin, Y.; Liu, Jing; Song, R.

    2017-05-01

    The spatial distribution features of electric field over three Alpha transmitters in Russia were analyzed based on the Demeter satellite records at local nighttime during the solar minimum in December of 2008, where the three transmitters are with the same emitted power of 500 kW and the same radio waves at 11.9 kHz, 12.6 kHz, and 14.9 kHz. The results of observations showed that the maximal electric field reached -80 to -70 dB (hereafter referred as to V/m) at 660 km altitude, and the horizontal covered area even exceeded 80° in longitude with electric field above -100 dB at 14.9 kHz. The lowest electric field and the smallest longitude scale were detected over Krasnodar (KRA), which is demonstrated that the lower ionosphere plays an important role in attenuating the energy as suggested by the simulation results from the full-wave propagation model. Another feature over KRA was the significant decrease in electromagnetic field strength at 11.9 kHz and 12.6 kHz, being one order of magnitude lower than the other two transmitters, where the lower hybrid resonance waves affected severely the whistler mode wave mode propagation. Compared with the ground very low frequency observations at Tonghai and Ya'an in China, the most complex variations were observed from KRA, while the east transmitter Khabarovsk maintained high strength of electromagnetic power in a longer distance than the middle transmitter Novosibirsk in local nighttime, which is consistent with the large covering scale in the topside ionosphere due to the enhancement by wave-particle interaction from the other transmitter.

  10. Stress-restress evokes sustained iNOS activity and altered GABA levels and NMDA receptors in rat hippocampus

    DEFF Research Database (Denmark)

    Harvey, Brian H; Oosthuizen, Frasia; Brand, Linda

    2004-01-01

    RATIONALE: Stress-related glucocorticoid and glutamate release have been implicated in hippocampal atrophy evident in patients with post-traumatic stress disorder (PTSD). Glutamatergic mechanisms activate nitric oxide synthase (NOS), while gamma-amino-butyric acid (GABA) may inhibit both...... glutamatergic and nitrergic transmission. Animal studies support a role for NOS in stress. OBJECTIVES: We have studied the role of NOS and glucocorticoids, as well as inhibitory and excitatory transmitters, in a putative animal model of PTSD that emphasizes repeated trauma. METHODS: Hippocampal NOS activity, N......-methyl-D-aspartate (NMDA) receptor binding characteristics and GABA levels were studied in Sprague-Dawley rats 21 days after exposure to a stress-restress paradigm, using radiometric analysis, radioligand studies and high-performance liquid chromatography (HPLC) analysis with electrochemical detection, respectively...

  11. Chemical release module facility

    Science.gov (United States)

    Reasoner, D. L.

    1980-01-01

    The chemical release module provides the capability to conduct: (1) thermite based metal vapor releases; (2) pressurized gas releases; (3) dispersed liquid releases; (4) shaped charge releases from ejected submodules; and (5) diagnostic measurements with pi supplied instruments. It also provides a basic R-F and electrical system for: (1) receiving and executing commands; (2) telemetering housekeeping data; (3) tracking; (4) monitoring housekeeping and control units; and (5) ultrasafe disarming and control monitoring.

  12. Modified cytoplasmic Ca2+ sequestration contributes to spinal cord injury-induced augmentation of nerve-evoked contractions in the rat tail artery.

    Directory of Open Access Journals (Sweden)

    Hussain Al Dera

    Full Text Available In rat tail artery (RTA, spinal cord injury (SCI increases nerve-evoked contractions and the contribution of L-type Ca2+ channels to these responses. In RTAs from unoperated rats, these channels play a minor role in contractions and Bay K8644 (L-type channel agonist mimics the effects of SCI. Here we investigated the mechanisms underlying the facilitatory actions of SCI and Bay K8644 on nerve-evoked contractions of RTAs and the hypothesis that Ca2+ entering via L-type Ca2+ channels is rapidly sequestered by the sarcoplasmic reticulum (SR limiting its role in contraction. In situ electrochemical detection of noradrenaline was used to assess if Bay K8644 increased noradrenaline release. Perforated patch recordings were used to assess if SCI changed the Ca2+ current recorded in RTA myocytes. Wire myography was used to assess if SCI modified the effects of Bay K8644 and of interrupting SR Ca2+ uptake on nerve-evoked contractions. Bay K8644 did not change noradrenaline-induced oxidation currents. Neither the size nor gating of Ca2+ currents differed between myocytes from sham-operated (control and SCI rats. Bay K8644 increased nerve-evoked contractions in RTAs from both control and SCI rats, but the magnitude of this effect was reduced by SCI. By contrast, depleting SR Ca2+ stores with ryanodine or cyclopiazonic acid selectively increased nerve-evoked contractions in control RTAs. Cyclopiazonic acid also selectively increased the blockade of these responses by nifedipine (L-type channel blocker in control RTAs, whereas ryanodine increased the blockade produced by nifedipine in both groups of RTAs. These findings suggest that Ca2+ entering via L-type channels is normally rapidly sequestered limiting its access to the contractile mechanism. Furthermore, the findings suggest SCI reduces the role of this mechanism.

  13. Coelomic implantation of satellite transmitters in the bar-tailed godwit (Limosa lapponica) and the bristle-thighed curlew (Numenius tahitiensis) using propofol, bupivacaine, and lidocaine

    Science.gov (United States)

    Mulcahy, Daniel M.; Gartrell, Brett D.; Gill, Robert E.; Tibbitts, T. Lee; Ruthrauff, Daniel R.

    2011-01-01

    Intravenous propofol was used as a general anesthetic with a 2∶1 (mg∶mg) adjunctive mixture of lidocaine and bupivacaine as local anesthetics infiltrated into the surgical sites for implantation of satellite transmitters into the right abdominal air sac of 39 female and 4 male bar-tailed godwits (Limosa lapponica baueri and Limosa lapponica menzbeiri) and 11 female and 12 male bristle-thighed curlews (Numenius tahitiensis). The birds were captured on nesting grounds in Alaska, USA, and on overwintering areas in New Zealand and Australia from 2005 through 2008. As it was developed, the mass of the transmitter used changed yearly from a low of 22.4 ± 0.2 g to a high of 27.1 ± 0.2 g and weighed 25.1 ± 0.2 g in the final year. The mean load ratios ranged from 5.2% to 7.7% for godwits and from 5.7% to 7.5% for curlews and exceeded 5% for all years, locations, and genders of both species. The maximum load ratio was 8.3% for a female bar-tailed godwit implanted in Australia in 2008. Three godwits and no curlews died during surgery. Most birds were hyperthermic upon induction but improved during surgery. Two godwits (one in New Zealand and one in Australia) could not stand upon release, likely due to capture myopathy. These birds failed to respond to treatment and were euthanized. The implanted transmitters were used to follow godwits through their southern and northern migrations, and curlews were followed on their southern migration.

  14. Evaluating in situ thermal transmittance of green buildings masonries—A case study

    Directory of Open Access Journals (Sweden)

    Francesco Asdrubali

    2014-01-01

    The paper presents the results of a measurement campaign of in situ thermal transmittance, performed in some buildings in the Umbria Region (Italy, designed implementing bio-architecture solutions. The analyzed walls were previously monitored with thermographic surveys in order to assess the correct application of the sensors. Results of the investigation show that in situ thermal transmittance measurements and theoretical calculated U-value are not in perfect agreement. The mismatch becomes important for monolithic structures such as walls made of thermal blocks without insulating layers.

  15. Transmittance of transparent windows with non-absorbing cap-shaped droplets condensed on their backside

    Science.gov (United States)

    Zhu, Keyong; Huang, Yong; Pruvost, Jeremy; Legrand, Jack; Pilon, Laurent

    2017-06-01

    This study aims to quantify systematically the effect of non-absorbing cap-shaped droplets condensed on the backside of transparent windows on their directional-hemispherical transmittance and reflectance. Condensed water droplets have been blamed to reduce light transfer through windows in greenhouses, solar desalination plants, and photobioreactors. Here, the directional-hemispherical transmittance was predicted by Monte Carlo ray-tracing method. For the first time, both monodisperse and polydisperse droplets were considered, with contact angle between 0 and 180°, arranged either in an ordered hexagonal pattern or randomly distributed on the window backside with projected surface area coverage between 0 and 90%. The directional-hemispherical transmittance was found to be independent of the size and spatial distributions of the droplets. Instead, it depended on (i) the incident angle, (ii) the optical properties of the window and droplets, and on (iii) the droplet contact angle and (iv) projected surface area coverage. In fact, the directional-hemispherical transmittance decreased with increasing incident angle. Four optical regimes were identified in the normal-hemispherical transmittance. It was nearly constant for droplet contact angles either smaller than the critical angle θcr (predicted by Snell's law) for total internal reflection at the droplet/air interface or larger than 180°-θcr. However, between these critical contact angles, the normal-hemispherical transmittance decreased rapidly to reach a minimum at 90° and increased rapidly with increasing contact angles up to 180°-θcr. This was attributed to total internal reflection at the droplet/air interface which led to increasing reflectance. In addition, the normal-hemispherical transmittance increased slightly with increasing projected surface area coverage for contact angle was smaller than θcr. However, it decreased monotonously with increasing droplet projected surface area coverage for contact

  16. High transmittance optical films based on quantum dot doped nanoscale polymer dispersed liquid crystals

    Science.gov (United States)

    Gandhi, Sahil Sandesh; Chien, Liang-Chy

    2016-04-01

    We propose a simple way to fabricate highly transparent nanoscale polymer dispersed liquid crystal (nano-PDLC) films between glass substrates and investigate their incident angle dependent optical transmittance properties with both collimated and Lambertian intensity distribution light sources. We also demonstrate that doping nano-PDLC films with 0.1% InP/ZnS core/shell quantum dots (QD) results in a higher optical transmittance. This work lays the foundation for such nanostructured composites to potentially serve as roll-to-roll coatable light extraction or brightness enhancement films in emissive display applications, superior to complex nanocorrugation techniques proposed in the past.

  17. A COMPARISON OF OBSERVATION WITH MODELING FOR ALBEDO AND TRANSMITTANCE OF SNOW

    OpenAIRE

    アオキ, テルオ; セコ, カツモト; アオキ, タダオ; フカボリ, マサシ; Teruo, AOKI; Katsumoto, SEKO; Tadao, AOKI; Masashi, FUKABORI

    1994-01-01

    Snow surface albedo and transmittance inside the snow have been investigated by observation and modeling. Observations were taken by a grating type spectrometer at Tokamachi in March 1993. The observed snow was old and very wet. Microscope photo-graphs of snow grains taken at this time indicate that snow grain is spherical particles with size of about 1.0μm. Surface albedo and transmittance of snow by a multiple scattering model for the atmosphere-snow system with pure snow grain size of 1.0μ...

  18. Design and Implementation of Double-Transmitter-Coil Antenna Used for the Tag Test System

    Directory of Open Access Journals (Sweden)

    Bin You

    2013-01-01

    Full Text Available At present, more and more electronic tags are used in Antitheft system; it is important to examine the performance of electronic tags. The traditional single-transmitter-coil antenna (STC antenna of the electronic tags tester has some serious drawbacks. So a novel double-transmitter-coil antenna (DTC antenna is presented in this paper. Compared to the traditional STC antenna, this new antenna has a more excellent performance in the tag test systems, especially when it is used for testing the quality factor of tags.

  19. Investigating Feasibility Of Multiple UHF Passive RFID Transmitters Using Backscatter Modulation Scheme In BCI Applications

    DEFF Research Database (Denmark)

    Al Ajrawi, Shams; Sarkar, Mahasweta; Rao, Ramesh

    simulatedbrain matter to a receiver located on the surface of a simulatedskull. These analyses are essential for building a brain computerinterface application. We showcase theoretical and experimentalresults based on a phantom model of the human brain usingpassive RFID as the implantable transmitter operating...... in UHFrange. Furthermore, we use backscatter modulation as a powertransfer mechanism. Investigation on the feasibility and appli-cability of implantable UHF Passive RFID transmitters insidethe brain is done for capturing multi-channel ECoG signals at ahigh data transfer rate. Detailed analysis have been done...

  20. Robustness of the universal optical transmittance in monolayer and multilayer graphene flakes under Coulomb interactions

    Science.gov (United States)

    Yadav, Premlata; Srivastava, Pawan Kumar; Ray, Nirat; Ghosh, Subhasis

    2016-09-01

    We present an experimental investigation on the universality of the optical transmittance of mono- and multilayer chemically exfoliated graphene flakes. By varying the exfoliating solvent, and thereby modulating the strength of electron-electron interactions, we find that the universality is not impacted over the visible region. The impact of modulating the interaction strength is clearly seen as shifts in the M-point exciton spectra. These shifts can then lead to a reduction in the wavelength regime over which universal wavelength independent optical transmittance is observed. At the level of first-order perturbation theory, our results are consistent with existing theoretical predictions for interaction corrections in optical properties of monolayer graphene.

  1. Effects of Aldrin-transdiol on neuromuscular facilitation and depression

    NARCIS (Netherlands)

    Akkermans, L.M.A.; Bercken, J. van den; Zalm, J.M. van der

    The effects of aldrin-transdiol, one of the active metabolites of the insecticide dieldrin, on evoked transmitter release, neuromuscular facilitation and neuromuscular depression have been studied in frog sartorius nerve-muscle preparations. Conventional techniques of intracellular recordings were

  2. The role of calcium in the effects of noradrenaline and phenoxybenzamine on adrenergic transmitter release from atria: no support for negative feedback of release

    OpenAIRE

    Kalsner, Stanley

    1981-01-01

    1 The relation of calcium ion influx into nerve terminals to presynaptic adrenoceptor function and the possible masking, by desensitization due to intraneuronal calcium accumulation, of the effects of adrenoceptor agonists and antagonists on presynaptic α-adrenoceptors was investigated in guinea-pig atria previously incubated with [3H]-noradrenaline.

  3. Impaired acetylcholine release from the myenteric plexus of Trichinella-infected rats

    Energy Technology Data Exchange (ETDEWEB)

    Collins, S.M.; Blennerhassett, P.A.; Blennerhassett, M.G.; Vermillion, D.L. (McMaster Univ., Hamilton, Ontario (Canada))

    1989-12-01

    We examined the release of acetylcholine (ACh) from jejunal longitudinal muscle-myenteric plexus preparations in noninfected control rats and in rats infected 6, 23, or 40 days previously with Trichinella spiralis. ACh release was assessed by preincubating the tissue with ({sup 3}H)choline and measuring the evoked release of tritium. The uptake of {sup 3}H was significantly less in tissue from T. spiralis-infected rats compared with control. In tissues from either infected or control animals, electrical field stimulation (30 V, 0.5 ms, 10 Hz for 1 min), or veratridine (6-30 microM) induced {sup 3}H release that was tetrodotoxin sensitive. Depolarization by KCl (25-75 mM) also caused {sup 3}H release, but this was only partially reduced by tetrodotoxin. Radiochromatographic analysis indicated evoked release of {sup 3}H to be almost entirely ({sup 3}H)ACh. In rats infected 6 days previously with T. spiralis, ({sup 3}H)ACh release induced by KCl, veratridine, and field stimulation were decreased at least 80%. The suppression of ({sup 3}H)ACh release induced by veratridine or KCl was fully reversible after 40 days postinfection, but field-stimulated responses remained approximately 50% of control values. These results indicate that T. spiralis infection in the rat is accompanied by a reversible suppression of ACh release from the longitudinal muscle-myenteric plexus of the jejunum.

  4. Clinical application of visual evoked potential in orbital cellulitis of infants

    Directory of Open Access Journals (Sweden)

    Xiao-Juan Jing

    2014-07-01

    Full Text Available AIM: To explore the visual evoked potential in infantile orbital cellulitis' clinical applications by monitoring the visual evoked potential changes in infantile orbital cellulitis before, during and after treatment.METHODS: Twenty-three cases of CT diagnosed single orbital cellulitis were examined by the visual evoked potentials. The affected eyes as observation group, and healthy eyes as control group. Comparative observation of visual evoked potential changes in amplitude and incubation period before, during and after the treatment. RESULTS: Compared with the control group, the observation group's visual evoked potential changes included reduced amplitude, extended incubation period. With the treatment progress, the observation group had gradual increase in amplitude, gradual reduction in incubation period. CONCLUSION: In infantile orbital cellulitis, the use of visual evoked potentials is a simple, feasible and effective method to monitoring the visual function during the treatment.

  5. Magnetic fields evoked by speech sounds in preschool children.

    Science.gov (United States)

    Pihko, Elina; Kujala, Teija; Mickos, Annika; Antell, Henrik; Alku, Paavo; Byring, Roger; Korkman, Marit

    2005-01-01

    Our objective was to study how well the auditory evoked magnetic fields (EF) reflect the behavioral discrimination of speech sounds in preschool children, and if they reveal the same information as simultaneously recorded evoked potentials (EP). EFs and EPs were recorded in 11 preschool children (mean age 6 years 9 months) using an oddball paradigm with two sets of speech stimuli consisting both of one standard and two deviants. After the brain activity recording, children were tested on behavioural discrimination of the same stimuli presented in pairs. There was a mismatch negativity (MMN) calculated from difference curves and its magnetic counterpart MMNm measured from the original responses only to those deviants, which were behaviourally easiest to discriminate from the standards. In addition, EF revealed significant differences between the locations of the activation depending on the hemisphere and stimulus properties. EF, in addition to reflecting the sound-discrimination accuracy in a similar manner as EP, also reflected the spatial differences in activation of the temporal lobes. These results suggest that both EPs and EFs are feasible for investigating the neural basis of sound discrimination in young children. The recording of EFs with its high spatial resolution reveals information on the location of the activated neural sources.

  6. A New Measure for Monitoring Intraoperative Somatosensory Evoked Potentials

    Science.gov (United States)

    Jin, Seung-Hyun; Kim, Jeong Eun; Choi, Young Doo

    2014-01-01

    Objective To propose a new measure for effective monitoring of intraoperative somatosensory evoked potentials (SEP) and to validate the feasibility of this measure for evoked potentials (EP) and single trials with a retrospective data analysis study. Methods The proposed new measure (hereafter, a slope-measure) was defined as the relative slope of the amplitude and latency at each EP peak compared to the baseline value, which is sensitive to the change in the amplitude and latency simultaneously. We used the slope-measure for EP and single trials and compared the significant change detection time with that of the conventional peak-to-peak method. When applied to single trials, each single trial signal was processed with optimal filters before using the slope-measure. In this retrospective data analysis, 7 patients who underwent cerebral aneurysm clipping surgery for unruptured aneurysm middle cerebral artery (MCA) bifurcation were included. Results We found that this simple slope-measure has a detection time that is as early or earlier than that of the conventional method; furthermore, using the slope-measure in optimally filtered single trials provides warning signs earlier than that of the conventional method during MCA clipping surgery. Conclusion Our results have confirmed the feasibility of the slope-measure for intraoperative SEP monitoring. This is a novel study that provides a useful measure for either EP or single trials in intraoperative SEP monitoring. PMID:25628803

  7. A wireless system for monitoring transcranial motor evoked potentials.

    Science.gov (United States)

    Farajidavar, Aydin; Seifert, Jennifer L; Bell, Jennifer E S; Seo, Young-Sik; Delgado, Mauricio R; Sparagana, Steven; Romero, Mario I; Chiao, J-C

    2011-01-01

    Intraoperative neurophysiological monitoring (IONM) is commonly used as an attempt to minimize neurological morbidity from operative manipulations. The goal of IONM is to identify changes in the central and peripheral nervous system function prior to irreversible damage. Intraoperative monitoring also has been effective in localizing anatomical structures, including peripheral nerves and sensorimotor cortex, which helps guide the surgeon during dissection. As part of IONM, transcranial motor evoked potentials (TcMEPs), and somatosensory evoked potentials (SSEPs) are routinely monitored. However, current wired systems are cumbersome as the wires contribute to the crowded conditions in the operating room and in doing so not only it limits the maneuverability of the surgeon and assistants, but also places certain demand in the total anesthesia required during surgery, due to setup preoperative time needed for proper electrode placement, due to the number and length of the wires, and critical identification of the lead wires needed for stimulation and recording. To address these limitations, we have developed a wireless TcMEP IONM system as a first step toward a multimodality IONM system. Bench-top and animal experiments in rodents demonstrated that the wireless method reproduced with high fidelity, and even increased the frequency bandwidth of the TcMEP signals, compared to wired systems. This wireless system will reduce the preoperative time required for IONM setup, add convenience for surgical staff, and reduce wire-related risks for patients during the operation.

  8. Evoked brain potentials and disability in brain-damaged patients.

    Science.gov (United States)

    Rappaport, M; Hall, K; Hopkins, K; Belleza, T; Berrol, S; Reynolds, G

    1977-08-01

    Various measures of evoked brain potential abnormality (EPA) were correlated with disability ratings (DR) for 35 brain-damaged patients. EPA data consisted of judgements of abnormality of ipsilateral, contralateral and bilateral responses to auditory and visual stimuli reflecting activity in the brain stem, subcortex and cortex. DR data were obtained from a scale developed for this study to quantize and categorize patients with a wide range of disabilities from coma to normal functioning. EPA scores based on visual and auditory cortical responses showed significantly positive correlations with degree of disability. Visual response correlation was .49, auditory .38 and combined visual and auditory .51. It was concluded that EPA measures can reflect disability independently of clinical information. They are useful in assessing brain function in general and, specifically, in assessing impairment of sensory function. The evoked potential technique was particularly useful in patients who were not able to participate fully in their own examination. There were indications that the technique may also be valuable in monitoring progress and in predicting clinical outcome in brain-damaged patients.

  9. Characteristics and clinical applications of ocular vestibular evoked myogenic potentials.

    Science.gov (United States)

    Kantner, C; Gürkov, R

    2012-12-01

    Recently, ocular vestibular evoked myogenic potentials (oVEMPs) have been described and added to the neuro-otologic test battery as a new measure for the vestibulo-ocular reflex. oVEMPs represent extraocular muscle activity in response to otolith stimulation e.g. by air-conducted sound or bone-conducted vibration. In response to vestibular stimulation, electromyographic activity of the extraocular muscles can be recorded by means of surface electrodes placed beneath the contralateral eye. oVEMPs are likely to reflect predominantly utricular function, while the widely established cervical vestibular evoked myogenic potentials (cVEMPs) assess saccular function. Thus, measuring oVEMPs and cVEMPs in addition to caloric and head impulse testing provides further evaluation of the vestibular system and enables quick and cost-effective assessment of otolith function. This review summarizes the neurophysiological properties of oVEMPs, gives recommendations for recording conditions and discusses oVEMP alterations in various disorders of the vestibular system. With increasing insight into oVEMP characteristics in vestibular disorders, e.g. Menière's disease and superior semicircular canal dehiscence syndrome, oVEMPs are becoming a promising new diagnostic tool for evaluating utricular function. Copyright © 2012 Elsevier B.V. All rights reserved.

  10. Somatosensory evoked potentials in children with severe head trauma.

    Science.gov (United States)

    Schalamon, Johannes; Singer, Georg; Kurschel, Senta; Höllwarth, Michael E

    2005-07-01

    We evaluated the predictive value of somatosensory evoked potentials (SEP) in a series of children with severe traumatic brain injury (TBI). The prospective clinical investigation was performed in a Level I paediatric trauma centre. We included 26 consecutive comatose paediatric patients aged from 1 month to 17 years (median age 11 years) following severe TBI (initial Glasgow Coma Score (GCS) 8 or below). Besides SEP recordings, the intracranial pressure and the results of an initial cranial CT scan were filed. The Glasgow Outcome Scale (GOS) was used to assess outcome at discharge. Thirteen children had normal SEP measurements, three patients had abnormal SEP recordings and a cortical response was bilaterally absent in ten children. Out of 26 children, 10 died whereas two remained in a persistent vegetative state. Only one child suffered from significant neurological deficits (GOS 3) at discharge. Seven patients survived with a GOS of 4 and six children survived without neurological impairment (GOS 5). Normal SEP indicated a favourable outcome in most children but did not rule out the occurrence of death, while absence of SEP was related to unfavourable outcome in all cases. Measurement of somatosensory evoked potentials provides valuable data for determining the prognosis at early coma stages. Our data show that an unfavourable outcome can be predicted with higher precision than a favourable outcome.

  11. Unwanted sexual experiences and cognitive appraisals that evoke mental contamination.

    Science.gov (United States)

    Ishikawa, Ryotaro; Kobori, Osamu; Shimizu, Eiji

    2015-01-01

    Mental contamination is a psychological sense of contamination that involves an internal, emotional feeling of dirtiness that may be evoked by unwanted thoughts and images, such as sexual assaults. This study aimed to investigate which types of unwanted sexual experiences evoke the strongest mental contamination, and to test the hypothesis that cognitive appraisals of an unwanted sexual experience predict indices of mental contamination (i.e. feeling of dirtiness, urge to wash, internal negative emotions, and external negative emotions). 148 female participants were asked to recall their most distressing unwanted sexual experiences. Indices of mental contamination and cognitive appraisals of the experience were then assessed. Our findings indicated that individuals recalling experiences related to rape felt more intense feelings of dirtiness than individuals recalling other types of unwanted sexual experience, such as verbal sexual assault, visual sexual assault, and forcible touching/frottage. In addition, hierarchical regression analyses demonstrated that a cognitive appraisal of perceived violation predicted all of the indices of mental contamination after controlling anxiety, depression, and fear of contact contamination. The present study demonstrated that an individual is at greatest risk of mental contamination if she has experienced rape/attempted rape, and if she makes a cognitive appraisal of violation regarding the incident.

  12. Nostalgia-Evoked Inspiration: Mediating Mechanisms and Motivational Implications.

    Science.gov (United States)

    Stephan, Elena; Sedikides, Constantine; Wildschut, Tim; Cheung, Wing-Yee; Routledge, Clay; Arndt, Jamie

    2015-10-01

    Six studies examined the nostalgia-inspiration link and its motivational implications. In Study 1, nostalgia proneness was positively associated with inspiration frequency and intensity. In Studies 2 and 3, the recollection of nostalgic (vs. ordinary) experiences increased both general inspiration and specific inspiration to engage in exploratory activities. In Study 4, serial mediational analyses supported a model in which nostalgia increases social connectedness, which subsequently fosters self-esteem, which then boosts inspiration. In Study 5, a rigorous evaluation of this serial mediational model (with a novel nostalgia induction controlling for positive affect) reinforced the idea that nostalgia-elicited social connectedness increases self-esteem, which then heightens inspiration. Study 6 extended the serial mediational model by demonstrating that nostalgia-evoked inspiration predicts goal pursuit (intentions to pursue an important goal). Nostalgia spawns inspiration via social connectedness and attendant self-esteem. In turn, nostalgia-evoked inspiration bolsters motivation. © 2015 by the Society for Personality and Social Psychology, Inc.

  13. Visual evoked potentials, reaction times and eye dominance in cricketers.

    Science.gov (United States)

    Thomas, N G; Harden, L M; Rogers, G G

    2005-09-01

    Few studies have examined the physiology of cricket, including the difference in ability between batsmen to make controlled contact with a ball bowled at high speed. We therefore measured visual evoked potentials and choice reaction times with dominant eyes, non-dominant eyes, and both eyes together, in 15 elite batsmen and 10 elite bowlers (aged 20.9 SD 1.9 years) and 9 control subjects (aged 20.2 SD 1.5 years). The latency and amplitude of waves N70, P100 and N145 were determined for each visual evoked potential (VEP). In addition interpeak latencies and peak to peak amplitudes were measured. The subjects also completed a choice reaction test to a visual stimulus. We found that cricketers were not more likely to have crossed dominance (dominant eye contralateral to dominant hand) than controls. Cricketers had a faster latency for VEP wave N70 than controls (p=0.03). However reaction time was not different between cricketers and the control group. Across all subjects, in comparison to monocular testing, binocular testing led to a faster choice reaction time (p=0.02) and larger amplitudes of VEP wave N70 (p=0.01). Visual processing during the first 100(-1)50 ms of the balls flight together with binocular vision facilitates retinal activation in talented cricketers.

  14. In vivo measurement of somatodendritic release of dopamine in the ventral tegmental area.

    Science.gov (United States)

    Kita, Justin M; Kile, Brian M; Parker, Lauren E; Wightman, R Mark

    2009-11-01

    The ventral tegmental area (VTA), the locus of mesolimbic dopamine cell bodies, contains dopamine. Experiments in brain slices have demonstrated that VTA dopamine can be released by local electrical stimulation. Measurements with both push-pull cannula and microdialysis in intact animals have also obtained evidence for releasable dopamine. Here we demonstrate that dopamine release in the VTA can be evoked by remote stimulations of the medial forebrain bundle (MFB) in the anesthetized rat. In initial experiments, the MFB was electrically stimulated while a carbon-fiber electrode was lowered to the VTA, with recording by fast-scan cyclic voltammetry. While release was not observed with the carbon fiber 4-6 mm below dura, a voltammetric response was observed at 6-8 mm below dura, but the voltammogram was poorly defined. At lower depths, in the VTA, dopamine release was evoked. Immunohistochemistry experiments with antibodies for tyrosine hydroxylase (TH) confirmed that dopamine processes were primarily found below 8 mm. Similarly, tissue content determined by liquid chromatography revealed serotonin but not dopamine dorsal to 8 mm with both dopamine and serotonin at lower depths. Evaluation of the VTA signal by pharmacological means showed that it increased with inhibitors of dopamine uptake, but release was not altered by D2 agents. Dopamine release in the VTA was frequency dependent and could be exhausted by stimulations longer than 5 s. Thus, VTA dopamine release can be evoked in vivo by remote stimulations and it resembles release in terminal regions, possessing a similar uptake mechanism and a finite releasable storage pool.

  15. Effect of surfactant chain length on drug release kinetics from microemulsion-laden contact lenses.

    Science.gov (United States)

    Maulvi, Furqan A; Desai, Ankita R; Choksi, Harsh H; Patil, Rahul J; Ranch, Ketan M; Vyas, Bhavin A; Shah, Dinesh O

    2017-05-30

    The effect of surfactant chain lengths [sodium caprylate (C8), Tween 20 (C12), Tween 80 (C18)] and the molecular weight of block copolymers [Pluronic F68 and Pluronic F 127] were studied to determine the stability of the microemulsion and its effect on release kinetics from cyclosporine-loaded microemulsion-laden hydrogel contact lenses in this work. Globule size and dilution tests (transmittance) suggested that the stability of the microemulsion increases with increase in the carbon chain lengths of surfactants and the molecular weight of pluronics. The optical transmittance of direct drug-laden contact lenses [DL-100] was low due to the precipitation of hydrophobic drugs in the lenses, while in microemulsion-laden lenses, the transmittance was improved when stability of the microemulsion was achieved. The results of in vitro release kinetics revealed that drug release was sustained to a greater extent as the stability of microemulsion was improved as well. This was evident in batch PF127-T80, which showed sustained release for 15days in comparison to batch DL-100, which showed release up to 7days. An in vivo drug release study in rabbit tear fluid showed significant increase in mean residence time (MRT) and area under curve (AUC) with PF-127-T80 lenses (stable microemulsion) in comparison to PF-68-SC lenses (unstable microemulsion) and DL-100 lenses. This study revealed the correlation between the stability of microemulsion and the release kinetics of drugs from contact lenses. Thus, it was inferred that the stable microemulsion batches sustained the release of hydrophobic drugs, such as cyclosporine from contact lenses for an extended period of time without altering critical lens properties. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Readily releasable pool of synaptic vesicles measured at single synaptic contacts.

    Science.gov (United States)

    Trigo, Federico F; Sakaba, Takeshi; Ogden, David; Marty, Alain

    2012-10-30

    To distinguish between different models of vesicular release in brain synapses, it is necessary to know the number of vesicles of transmitter that can be released immediately at individual synapses by a high-calcium stimulus, the readily releasable pool (RRP). We used direct stimulation by calcium uncaging at identified, single-site inhibitory synapses to investigate the statistics of vesicular release and the size of the RRP. Vesicular release, detected as quantal responses in the postsynaptic neuron, showed an unexpected stochastic variation in the number of quanta from stimulus to stimulus at high intracellular calcium, with a mean of 1.9 per stimulus and a maximum of three or four. The results provide direct measurement of the RRP at single synaptic sites. They are consistent with models in which release proceeds from a small number of vesicle docking sites with an average occupancy around 0.7.

  17. Optogenetic Control of Serotonin and Dopamine Release in Drosophila Larvae

    Science.gov (United States)

    2014-01-01

    Optogenetic control of neurotransmitter release is an elegant method to investigate neurobiological mechanisms with millisecond precision and cell type-specific resolution. Channelrhodopsin-2 (ChR2) can be expressed in specific neurons, and blue light used to activate those neurons. Previously, in Drosophila, neurotransmitter release and uptake have been studied after continuous optical illumination. In this study, we investigated the effects of pulsed optical stimulation trains on serotonin or dopamine release in larval ventral nerve cords. In larvae with ChR2 expressed in serotonergic neurons, low-frequency stimulations produced a distinct, steady-state response while high-frequency patterns were peak shaped. Evoked serotonin release increased with increasing stimulation frequency and then plateaued. The steady-state response and the frequency dependence disappeared after administering the uptake inhibitor fluoxetine, indicating that uptake plays a significant role in regulating the extracellular serotonin concentration. Pulsed stimulations were also used to evoke dopamine release in flies expressing ChR2 in dopaminergic neurons and similar frequency dependence was observed. Release due to pulsed optical stimulations was modeled to determine the uptake kinetics. For serotonin, Vmax was 0.54 ± 0.07 μM/s and Km was 0.61 ± 0.04 μM; and for dopamine, Vmax was 0.12 ± 0.03 μM/s and Km was 0.45 ± 0.13 μM. The amount of serotonin released per stimulation pulse was 4.4 ± 1.0 nM, and the amount of dopamine was 1.6 ± 0.3 nM. Thus, pulsed optical stimulations can be used to mimic neuronal firing patterns and will allow Drosophila to be used as a model system for studying mechanisms underlying neurotransmission. PMID:24849718

  18. A Field Evaluation of an External and Neutrally Buoyant Acoustic Transmitter for Juvenile Salmon: Implications for Estimating Hydroturbine Passage Survival

    Science.gov (United States)

    Brown, Richard S.; Deng, Z. Daniel; Cook, Katrina V.; Pflugrath, Brett D.; Li, Xinya; Fu, Tao; Martinez, Jayson J.; Li, Huidong; Trumbo, Bradly A.; Ahmann, Martin L.; Seaburg, Adam G.

    2013-01-01

    Turbine-passed fish are exposed to rapid decreases in pressure which can cause barotrauma. The presence of an implanted telemetry tag increases the likelihood of injury or death from exposure to pressure changes, thus potentially biasing studies evaluating survival of turbine-passed fish. Therefore, a neutrally buoyant externally attached tag was developed to eliminate this bias in turbine passage studies. This new tag was designed not to add excess mass in water or take up space in the coelom, having an effective tag burden of zero with the goal of reducing pressure related biases to turbine survival studies. To determine if this new tag affects fish performance or susceptibility to predation, it was evaluated in the field relative to internally implanted acoustic transmitters (JSATS; Juvenile Salmon Acoustic Telemetry System) used widely for survival studies of juvenile salmonids. Survival and travel time through the study reach was compared between fish with either tag type in an area of high predation in the Snake and Columbia rivers, Washington. An additional group of fish affixed with neutrally-buoyant dummy external tags were implanted with passive integrated transponder (PIT) tags and recovered further downstream to assess external tag retention and injury. There were no significant differences in survival to the first detection site, 12 river kilometers (rkm) downstream of release. Travel times were also similar between groups. Conversely, externally-tagged fish had reduced survival (or elevated tag loss) to the second detection site, 65 rkm downstream. In addition, the retention study revealed that tag loss was first observed in fish recaptured approximately 9 days after release. Results suggest that this new tag may be viable for short term (<8 days) single-dam turbine-passage studies and under these situations, may alleviate the turbine passage-related bias encountered when using internal tags, however further research is needed to confirm this. PMID

  19. A field evaluation of an external and neutrally buoyant acoustic transmitter for juvenile salmon: implications for estimating hydroturbine passage survival.

    Directory of Open Access Journals (Sweden)

    Richard S Brown

    Full Text Available Turbine-passed fish are exposed to rapid decreases in pressure which can cause barotrauma. The presence of an implanted telemetry tag increases the likelihood of injury or death from exposure to pressure changes, thus potentially biasing studies evaluating survival of turbine-passed fish. Therefore, a neutrally buoyant externally attached tag was developed to eliminate this bias in turbine passage studies. This new tag was designed not to add excess mass in water or take up space in the coelom, having an effective tag burden of zero with the goal of reducing pressure related biases to turbine survival studies. To determine if this new tag affects fish performance or susceptibility to predation, it was evaluated in the field relative to internally implanted acoustic transmitters (JSATS; Juvenile Salmon Acoustic Telemetry System used widely for survival studies of juvenile salmonids. Survival and travel time through the study reach was compared between fish with either tag type in an area of high predation in the Snake and Columbia rivers, Washington. An additional group of fish affixed with neutrally-buoyant dummy external tags were implanted with passive integrated transponder (PIT tags and recovered further downstream to assess external tag retention and injury. There were no significant differences in survival to the first detection site, 12 river kilometers (rkm downstream of release. Travel times were also similar between groups. Conversely, externally-tagged fish had reduced survival (or elevated tag loss to the second detection site, 65 rkm downstream. In addition, the retention study revealed that tag loss was first observed in fish recaptured approximately 9 days after release. Results suggest that this new tag may be viable for short term (<8 days single-dam turbine-passage studies and under these situations, may alleviate the turbine passage-related bias encountered when using internal tags, however further research is needed to

  20. Endocannabinoids produced upon action potential firing evoke a Cl(-) current via type-2 cannabinoid receptors in the medial prefrontal cortex.

    Science.gov (United States)

    den Boon, Femke S; Chameau, Pascal; Houthuijs, Kas; Bolijn, Simone; Mastrangelo, Nicolina; Kruse, Chris G; Maccarrone, Mauro; Wadman, Wytse J; Werkman, Taco R

    2014-12-01

    The functional presence of type-2 cannabinoid receptors (CB2Rs) in layer II/III pyramidal neurons of the rat medial prefrontal cortex (mPFC) was recently demonstrated. In the present study, we show that the application of the endocannabinoids (eCBs) 2-arachidonoylglycerol (2-AG) and methanandamide [a stable analog of the eCB anandamide (AEA)] can activate CB2Rs of mPFC layer II/III pyramidal neurons, which subsequently induces a Cl(-) current. In addition, we show that action potential (AP) firing evoked by 20-Hz current injections results in an eCB-mediated opening of Cl(-) channels via CB2R activation. This AP-evoked synthesis of eCBs is dependent on the Ca(2+) influx through N-type voltage-gated calcium channels. Our results indicate that 2-AG is the main eCB involved in this process. Finally, we demonstrate that under physiologically relevant intracellular Cl(-) conditions, 20-Hz AP firing leads to a CB2R-dependent reduction in neuronal excitability. Altogether, our data indicate that eCBs released upon action potential firing can modulate, through CB2R activation, neuronal activity in the mPFC. We discuss how this may be a mechanism to prevent excessive neuronal firing.

  1. Remote Determination of Cloud Temperature and Transmittance from Spectral Radiance Measurements: Method and Results

    Science.gov (United States)

    1996-10-01

    CONTROL DATA 2. SECURITY CLASSIFICATION 1...atmospherics temperatura and humidity profiles. Validation tests performed on experimental spectra demonstrate the occuracy of the method with typical...indicated as with the title.) Passive Remota Sensing Infrared Spectra Cloud Temperatura Cloud Transmittance FTIR Spectrometer Icing Hazard Detection (DCD03E.IFO - 95.02.22) UNCLASSIFIED SECURITY CLASSIFICATION OF FORM

  2. Abdominally implanted satellite transmitters affect reproduction and survival rather than migration of large shorebirds

    NARCIS (Netherlands)

    Hooijmeijer, J.C.E.W.; Gill, Robert E.; Mulcahy, D.M.; Tibbitts, T. Lee; Kentie, Rosemarie; Gerritsen, Gerrit J.; Bruinzeel, Leo W.; Tijssen, David C.; Harwood, Christopher M.; Piersma, Theunis

    Satellite telemetry has become a common technique to investigate avian life-histories, but whether such tagging will affect fitness is a critical unknown. In this study, we evaluate multi-year effects of implanted transmitters on migratory timing and reproductive performance in shorebirds.

  3. Design of an Omnidirectional Multibeam Transmitter for High-Speed Indoor Wireless Communications

    Directory of Open Access Journals (Sweden)

    Jaw-Luen Tang

    2010-01-01

    Full Text Available For future high speed indoor wireless communication, diffuse wireless optical communications offer more robust optical links against shadowing than line-of-sight links. However, their performance may be degraded by multipath dispersion arising from surface reflections. We have developed a multipath diffusive propagation model capable of providing channel impulse responses data. It is aimed to design and simulate any multibeam transmitter under a variety of indoor environments. In this paper, a multi-beam transmitter system associated with hemisphere structure is proposed to fight against the diverse effects of multipath distortion albeit, at the cost of increased laser power and cost. Simulation results of multiple impulse responses showed that this type of multi-beam transmitter can significantly improve the performance of BER suitable for high bit rate application. We present the performance and simulation results for both line-of-sight and diffuse link configurations. We propose a design of power radiation pattern for a transmitter in achieving uniform and full coverage of power distributions for diffuse indoor optical wireless systems.

  4. Estimation of thermal transmittance based on temperature measurements with the application of perturbation numbers

    Science.gov (United States)

    Nowoświat, Artur; Skrzypczyk, Jerzy; Krause, Paweł; Steidl, Tomasz; Winkler-Skalna, Agnieszka

    2017-12-01

    Fast estimation of thermal transmittance based on temperature measurements is uncertain, and the obtained results can be burdened with a large error. Nevertheless, such attempts should be undertaken merely due to the fact that a precise measurement by means of heat flux measurements is not always possible in field conditions (resentment of the residents during the measurements carried out inside their living quarters), and the calculation methods do not allow for the nonlinearity of thermal insulation, heat bridges or other fragments of building envelope of diversified thermal conductivity. The present paper offers the estimation of thermal transmittance and internal surface resistance with the use of temperature measurements (in particular with the use of thermovision). The proposed method has been verified through tests carried out on a laboratory test stand built in the open space, subjected to the influence of real meteorological conditions. The present elaboration involves the estimation of thermal transmittance by means of temperature measurements. Basing on the mentioned estimation, the authors present correction coefficients which have impact on the estimation accuracy. Furthermore, in the final part of the paper, various types of disturbance were allowed for using perturbation numbers, and the introduced by the authors "credibility area of thermal transmittance estimation" was determined.

  5. Auxiliary VHF transmitter to aid recovery of solar Argos/GPS PTTs

    Science.gov (United States)

    Christopher P. Hansen; Mark A. Rumble; R. Scott Gamo; Joshua J. Millspaugh

    2014-01-01

    While conducting greater sage-grouse (Centrocercus urophasianus) research, we found that solar-powered global positioning systems platform transmitter terminals (GPS PTTs) can be lost if the solar panel does not receive adequate sunlight. Thus, we developed 5-g (mortality sensor included; Prototype A) and 9.8-g (no mortality sensor; Prototype B) auxiliary very high...

  6. Photonic chip based 1.28 Tbaud transmitter optimization and receiver OTDM demultiplexing

    DEFF Research Database (Denmark)

    Vo, T.D.; Hu, Hao; Galili, Michael

    2010-01-01

    We propose chip-based Tbaud processing for all-optical performance monitoring, switching and demultiplexing. We demonstrate the first transmitter optimization and receiver-end demultiplexing of 1.28 Tbit/s OOK signals. Both exploited Kerr nonlinearity in dispersion-engineered As$_2$S$_3$ planar...

  7. Low power wide spectrum optical transmitter using avalanche mode LEDs in SOI CMOS technology

    NARCIS (Netherlands)

    Agarwal, Vishal Vishal; Dutta, Satadal; Annema, Anne J.; Hueting, Raymond Josephus Engelbart; Steeneken, P.G.; Nauta, Bram

    2017-01-01

    This paper presents a low power monolithically integrated optical transmitter with avalanche mode light emitting diodes in a 140 nm silicon-on-insulator CMOS technology. Avalanche mode LEDs in silicon exhibit wide-spectrum electroluminescence (400 nm < λ < 850 nm), which has a significant overlap

  8. High-power multi-beam diode laser transmitter for a flash imaging lidar

    Science.gov (United States)

    Holmlund, Christer; Aitta, Petteri; Kivi, Sini; Mitikka, Risto; Tyni, Lauri; Heikkinen, Veli

    2013-10-01

    VTT Technical Research Centre of Finland is developing the transmitter for the "Flash Optical Sensor for TErrain Relative NAVigation" (FOSTERNAV) multi-beam flash imaging lidar. FOSTERNAV is a concept demonstrator for new guidance, navigation and control (GNC) technologies to fulfil the requirements for landing and docking of spacecraft as well as for navigation of rovers. This paper presents the design, realisation and testing of the multi-beam continuous-wave (CW) laser transmitter to be used in a 256x256 pixel flash imaging lidar. Depending on the target distance, the lidar has three operation modes using either several beams with low divergence or one single beam with a large divergence. This paper describes the transmitter part of the flash imaging lidar with focus on the electronics and especially the laser diode drivers. The transmitter contains eight fibre coupled commercial diode laser modules with a total peak optical power of 32 W at 808 nm. The main requirement for the laser diode drivers was linear modulation up to a frequency of 20 MHz allowing, for example, low distortion chirps or pseudorandom binary sequences. The laser modules contain the laser diode, a monitoring photodiode, a thermo-electric cooler, and a thermistor. The modules, designed for non-modulated and low-frequency operation, set challenging demands on the design of the drivers. Measurement results are presented on frequency response, and eye diagrams for pseudo-random binary sequences.

  9. Surface morphology of pre-stressed bilayer shells for tunable optical transmittance

    Science.gov (United States)

    Al-Rashed, Rashed; López Jiménez, Francisco; Marthelot, Joel; Lee, Anna; Reis, Pedro

    We introduce a new class of pre-stressed bilayer shells, whose surface morphology can be used to smoothly tune their optical transmittance by pneumatic actuation. Each sample is fabricated by pressurizing a disk made out of an optically clear silicone-based rubber to bulge it into a nearly hemispherical pre-strained shell. The surface of this shell is then taken as a substrate and coated with a thin layer of a polymer suspension with black micron-sized dye particles, which, upon curing, can make the samples opaque. The sample becomes planar when it is depressurized to remove the pre-strain, and its surface develops a complex topography that significantly affects its optical transmittance (i.e. the amount of light that passes through the sample). Re-pressurization of the samples allow for their transmittance to be smoothly tuned in a reversible manner. We explore the parameter space of the system by systematically varying its geometric and material properties. A phase diagram is then constructed where we characterize the transmittance of each of the surface patterns at varying levels of pre-strain.

  10. Breaking the Transmitter-Receiver Isolation Barrier in Mobile Handsets with Spatial Duplexing

    DEFF Research Database (Denmark)

    Alrabadi, Osama; Tatomirescu, Alexandru; Knudsen, Mikael

    2013-01-01

    In full-duplex radio communication systems like eUTRAN, CDMA-2000, the radio transmitter (Tx) is active at the same time as the radio receiver (Rx). The Tx and the Rx will be using separate dedicated frequency bands and the Tx-Rx isolation is ensured by duplex filters. However, agile duplexers...

  11. Reading Rooms of Russian Province in 1920s as Transmitters of Soviet Values

    Directory of Open Access Journals (Sweden)

    Vadim P. Nikolashin

    2014-12-01

    Full Text Available The article features regional aspects of reading room activities in the 1920s as transmitters of Soviet values. Authors analyze forms and methods of work of this type of socio-cultural institutions, study specifics of relationship of countrymen. The conducted analysis allows speaking about positive impact by reading rooms on evolution of a country life.

  12. 47 CFR 22.727 - Power limits for conventional rural radiotelephone transmitters.

    Science.gov (United States)

    2010-10-01

    ... radiotelephone transmitters. 22.727 Section 22.727 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED... this section. (a) Maximum ERP. The effective radiated power (ERP) of central office and rural... circumstances. Frequency range (MHz) Maximum ERP (watts) 152-153 1400 157-159 150 454-455 3500 459-460 150 (b...

  13. An Embedded Web based Real Time Application for Remote Monitoring & Controlling of MST RADAR Transmitters

    Directory of Open Access Journals (Sweden)

    Nagabhushan Raju KONDURU

    2012-01-01

    Full Text Available An embedded web based radar transmitters control & interlock system is developed in the present work. This research activity facilitates controlling and monitoring 53-MHz, 2.5 Mega-watt peak power MST radar triode based transmitters via internet. This radar is a prime instrument for atmospheric science research with 32 transmitters powering 1024-element antenna array. A comprehensive safety interlock is built in to protect expensive devices; by sensing anode voltages, heater currents and airflow etc. It automatically prevents fatal damages by switching transmitter / RF off. The system is designed and developed using RISC microcontroller ARM LPC 2148 based on a 32- bit ARM7 TDMI-S CPU with real-time emulation and embedded trace support and 512 kB high speed flash memory. The microcontroller is a blend of serial communication interface, dual 10-bit ADC’s and fast GPIO. Ethernet controller LM3S6432 is used to send sensors’ digitalized data over internet.

  14. Effect of package light transmittance on the vitamin content of pasteurized whole milk

    NARCIS (Netherlands)

    Soffert, A.; Pieper, G.; Jetten, J.

    2006-01-01

    Pasteurized whole milk (3% fat) was stored under fluorescent light at 8°C in clear 1 litre polyethylene terephthalate (PET) bottles and three variants of pigmented PET bottles with different light transmittance. Changes in the vitamin content were monitored over a period of 10 days. Milk packed in

  15. Abdominally implanted satellite transmitters affect reproduction and survival rather than migration of large shorebirds

    NARCIS (Netherlands)

    Hooijmeijer, J.C.E.W.; Gill, R.E.; Mulcahy, D.M.; Tibbitts, T.L.; Kentie, R.; Gerritsen, G.J.; Bruinzeel, L.W.; Tijssen, D.C.; Harwood, C.M.; Piersma, T.

    2014-01-01

    Satellite telemetry has become a common technique to investigate avian life-histories, but whether such tagging will affect fitness is a critical unknown. In this study, we evaluate multi-year effects of implanted transmitters on migratory timing and reproductive performance in shorebirds.

  16. Development and testing of attachment methods for pop-up satellite archival transmitters in European eel

    DEFF Research Database (Denmark)

    Økland, Finn; Thorstad, Eva B.; Westerberg, Håkan

    2013-01-01

    Background Four methods for attaching pop-up satellite transmitters to European eel were tested in the laboratory by recording long-term tag retention, growth and survival; short-term behavioral responses; and physical damage from attachments. Results All eels survived until they lost their tag...

  17. 47 CFR 80.169 - Operators required to adjust transmitters or radar.

    Science.gov (United States)

    2010-10-01

    ... radar. 80.169 Section 80.169 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND... Requirements § 80.169 Operators required to adjust transmitters or radar. (a) All adjustments of radio... such equipment which may affect the proper operation of the station, must be performed by or under the...

  18. Topology optimised photonic crystal waveguide intersections with high-transmittance and low crosstalk

    DEFF Research Database (Denmark)

    Ikeda, N; Sugimoto, Y; Watanabe, Y

    2006-01-01

    Numerical and experimental studies on the photonic crystal waveguide intersection based on the topology optimisation design method are reported and the effectiveness of this technique is shown by achieving high transmittance spectra with low crosstalk for the straightforward beam-propagation line...

  19. 22 CFR 1423.26 - Transmittal of the Administrative Law Judge's decision to the Board; exceptions.

    Science.gov (United States)

    2010-04-01

    ... 22 Foreign Relations 2 2010-04-01 2010-04-01 true Transmittal of the Administrative Law Judge's decision to the Board; exceptions. 1423.26 Section 1423.26 Foreign Relations FOREIGN SERVICE LABOR...; AND THE FOREIGN SERVICE IMPASSE DISPUTES PANEL FOREIGN SERVICE LABOR RELATIONS BOARD AND GENERAL...

  20. Spatial integration of local transmitter responses in motoneurones of the turtle spinal cord in vitro

    DEFF Research Database (Denmark)

    Skydsgaard, Morten Arnika; Hounsgaard, J

    1994-01-01

    1. Integration of responses to local activation of transmitter receptors in the dendrites of motoneurones was investigated in a slice preparation of the turtle spinal cord. Membrane-active substances were applied from up to three independent iontophoresis electrodes during intracellular recording...

  1. Measurement of the total solar energy transmittance (g-value) for conventional glazings

    DEFF Research Database (Denmark)

    Duer, Karsten

    1998-01-01

    Three different glazings have been investigated in the Danish experimental setup METSET. (A device for calorimetric measurement of total solar energy transmittance - g-value).The purpose of the measurements is to increase the confidence in the calorimetric measurements. This is done by comparison...

  2. Inhibitory effect of cholesteryl gamma-aminobutyrate on evoked activity in rat hippocampal slices.

    Science.gov (United States)

    Hesse, G W; Shashoua, V E; Jacob, J N

    1985-02-01

    Cholesteryl gamma-aminobutyrate (C-G) readily crosses the blood-brain barrier and has properties that suggest that it may be a potential gamma-aminobutyric acid (GABA)-mimetic compound. The effect of this compound on the orthodromically-evoked discharge of hippocampal pyramidal cells was investigated using slices of rat hippocampus maintained in vitro. The compound produced dose-dependent inhibition of the discharge of pyramidal cells. The magnitude of the inhibitory effect was somewhat less than that produced by a similar dose of GABA, but the duration of the inhibition was prolonged by about 10-fold over that produced by GABA. The inhibition produced by cholesteryl gamma-aminobutyrate was blocked by the addition of picrotoxin to the incubation medium, and by replacement of chloride with isethionate. In addition, pretreatment of slices with the irreversible esterase inhibitor, phenylmethylsulfonylfluoride, attenuated the effects of cholesteryl gamma-aminobutyrate, but not that of GABA. These results suggest that cholesteryl gamma-aminobutyrate has GABA-like actions in the CNS, and that its activity is largely dependent upon enzymatic release of GABA from the compound by esterases present in the tissue.

  3. Contribution of glutamatergic systems in locus coeruleus to nucleus paragigantocellularis stimulation-evoked behavior.

    Science.gov (United States)

    Liu, N; Ho, I K; Rockhold, R W

    1999-08-01

    The role of extracellular glutamate, within the locus coeruleus, in mediation of the behavioral signs elicited by electrical stimulation of the nucleus paragigantocellularis (PGi) was investigated in conscious, opioid-naive rats. Each rat was prepared with a chronically implanted unilateral electrode within the PGi and a microdialysis guide cannula directed at the ipsilateral locus coeruleus. Opioid withdrawal-like behaviors (rearing, teeth-chattering, wet-dog shakes, etc.) and increases in extracellular glutamate concentrations within the locus coeruleus were evoked, in a frequency-dependent (0.5-50 Hz) manner, during PGi stimulation. Reverse dialysis perfusion of the locus coeruleus with the nonspecific glutamate receptor antagonist, kynurenic acid (0.1, 1 mM), reduced the intensity of stimulation-induced behaviors by roughly 50%, but had no effect on the corresponding increases in glutamate concentrations. Perfusion of the locus coeruleus with the glutamate transporter inhibitor, L-trans-pyrrolidine dicarboxylic acid, at 1, but not at 0.1, mM significantly increased glutamate levels in dialysates. Neither concentration of the transporter inhibitor altered the behavioral score. The results indicate that the opioid withdrawal-like behaviors elicited by electrical stimulation of the brainstem at the site of the PGi are positively correlated with locus coeruleus levels of glutamate, and suggest further that the behaviors are partially mediated by release of glutamate within the locus coeruleus or its immediate vicinity.

  4. Emotional stress evoked by classical fear conditioning induces yawning behavior in rats.

    Science.gov (United States)

    Kubota, Natsuko; Amemiya, Seiichiro; Yanagita, Shinya; Nishijima, Takeshi; Kita, Ichiro

    2014-04-30

    Yawning is often observed not only in a state of boredom or drowsiness but also in stressful emotional situations, suggesting that yawning is an emotional behavior. However, the neural mechanisms for yawning during stressful emotional situations have not been fully determined, though previous studies have suggested that both parvocellular oxytocin (OT) and corticotropin-releasing factor (CRF) neurons in the hypothalamic paraventricular nucleus (PVN) are responsible for induction of yawning. Thus, using ethological observations and c-Fos immunohistochemistry, we examined whether emotional stress evoked by classical fear conditioning is involved in induction of yawning behavior in freely moving rats. Emotional stress induced yawning behavior that was accompanied by anxiety-related behavior, and caused neuronal activation of the central nucleus of the amygdala (CeA), as well as increases in activity of both OT and CRF neurons in the PVN. These results suggest that emotional stress may induce yawning behavior, in which the neuronal activation of the CeA may have a key role. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  5. Polarization-, carrier-, and format-selectable optical flow generation based on a multi-flow transmitter using passive polymers

    DEFF Research Database (Denmark)

    Katopodis, V.; Spyropoulou, M.; Tsokos, C.

    2016-01-01

    generation is feasible with appropriate distribution of the client data in the digital domain and encapsulation into OTN containers. Configuration of the electrical and optical transmitter resources is performed via a developed software defined optics (SDO) platform residing on top of the transmitter...

  6. 47 CFR 95.420 - (CB Rule 20) May I connect my CB station transmitter to a telephone?

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false (CB Rule 20) May I connect my CB station... Operate A Cb Station § 95.420 (CB Rule 20) May I connect my CB station transmitter to a telephone? (a) You may connect your CB station transmitter to a telephone if you comply with all of the following: (1...

  7. A new topology and control method for electromagnetic transmitter power supplies

    Science.gov (United States)

    Zhang, Yiming; Zhang, Jialin; Yuan, Dakang

    2017-04-01

    As essential equipment for electromagnetic exploration, electromagnetic transmitter reverse the steady power supply with desired frequency and transmit the power through grounding electrodes. To obtain effective geophysical data during deep exploration, the transmitter needs to be high-voltage, high-current, with high-accuracy output, and yet compact and light. The researches on the power supply technologies for high-voltage high-power electromagnetic transmitter is of significant importance to the deep geophysical explorations. Therefore, the performance of electromagnetic transmitter is mainly subject to the following two aspects: the performance of emission current and voltage, and the power density. These requirements bring technical difficulties to the development of power supplies. Conventionally, high-frequency switching power supplies are applied in the design of a high-power transmitter power supply. However, the structure of the topology is complicate, which may reduce the controllability of the output voltage and the reliability of the system. Without power factor control, the power factor of the structure is relatively low. Moreover high switching frequency causes high loss. With the development of the PWM (pulse width modulation) technique, its merits of simple structure, low loss, convenient control and unit power factor have made it popular in electrical energy feedback, active filter, and power factor compensation. Studies have shown that using PWM converters and space vector modulation have become the trend in designing transmitter power supply. However, the earth load exhibits different impedances at different frequencies. Thus ensuing high-accuracy and a stable output from a transmitter power supply in harsh environment has become a key topic in the design of geophysical exploration instruments. Based on SVPWM technology, an electromagnetic transmitter power supply has been designed and its control strategy has been studied. The transmitting

  8. Assessment of visual disability using visual evoked potentials.

    Science.gov (United States)

    Jeon, Jihoon; Oh, Seiyul; Kyung, Sungeun

    2012-08-06

    The purpose of this study is to validate the use of visual evoked potential (VEP) to objectively quantify visual acuity in normal and amblyopic patients, and determine if it is possible to predict visual acuity in disability assessment to register visual pathway lesions. A retrospective chart review was conducted of patients diagnosed with normal vision, unilateral amblyopia, optic neuritis, and visual disability who visited the university medical center for registration from March 2007 to October 2009. The study included 20 normal subjects (20 right eyes: 10 females, 10 males, ages 9-42 years), 18 unilateral amblyopic patients (18 amblyopic eyes, ages 19-36 years), 19 optic neuritis patients (19 eyes: ages 9-71 years), and 10 patients with visual disability having visual pathway lesions. Amplitude and latencies were analyzed and correlations with visual acuity (logMAR) were derived from 20 normal and 18 amblyopic subjects. Correlation of VEP amplitude and visual acuity (logMAR) of 19 optic neuritis patients confirmed relationships between visual acuity and amplitude. We calculated the objective visual acuity (logMAR) of 16 eyes from 10 patients to diagnose the presence or absence of visual disability using relations derived from 20 normal and 18 amblyopic eyes. Linear regression analyses between amplitude of pattern visual evoked potentials and visual acuity (logMAR) of 38 eyes from normal (right eyes) and amblyopic (amblyopic eyes) subjects were significant [y = -0.072x + 1.22, x: VEP amplitude, y: visual acuity (logMAR)]. There were no significant differences between visual acuity prediction values, which substituted amplitude values of 19 eyes with optic neuritis into function. We calculated the objective visual acuity of 16 eyes of 10 patients to diagnose the presence or absence of visual disability using relations of y = -0.072x + 1.22 (-0.072). This resulted in a prediction reference of visual acuity associated with malingering vs. real

  9. The Intraoperative Effect of Methadone on Somatosensory Evoked Potentials.

    Science.gov (United States)

    Higgs, Maureen; Hackworth, Robert J; John, King; Riffenburgh, Robert; Tomlin, Jeffrey; Wamsley, Brian

    2017-04-01

    Evoked potentials (EP), both somatosensory evoked potentials (SSEP) and transcranial motor evoked potentials (TcMEP), are often used during complex spine surgery to monitor the integrity of spinal pathways during operations in or around the spine. Changes in these monitored EP signals (increased latency and decreased amplitude) may result from ischemia, direct surgical injury, changes in blood pressure, hypoxia, changes in CO2 tension, and anesthetic agents. Typically, a clinically significant change for SSEPs is defined as an increase in latency >10% or a decrease of amplitude >50%. A clinically significant change for TcMEPs is much more complex but is also described in terms of large signal loss or decrease. Opioids have been shown to both increase latency and decrease the amplitude of SSEPs, although this change is usually not clinically significant. There has been a renewed interest in methadone for use in spine and other complex surgeries. However, the effect of methadone on intraoperative monitoring of SSEPs and TcMEPs is unknown. We present the first study to directly look at the effects of methadone on SSEP and TcMEP monitoring during complex spine surgery. The goal of this study was to observe the effect of methadone on an unrandomized set of patients. The primary endpoint was methadone's effect on SSEPs, and the secondary endpoint was methadone's effect on TcMEPs. Adult patients undergoing spine surgery requiring intraoperative neuromonitoring were induced with general anesthesia and had a baseline set of SSEPs and TcMEPs recorded. Next, methadone dosed 0.2 mg/kg/lean body weight was given. Repeat SSEPs and TcMEPs were recorded at 5, 10, and 15 minutes, with the timing based on distribution half-life of methadone between 6 and 8 minutes. Postoperatively, adverse events from methadone administration were collected. There was a statistically significant difference found in SSEPs for N20 latency (95% confidence interval [CI], 0.17-0.53; P=0.028), P37 latency

  10. The Princip cult and what it evokes in Hungary

    Directory of Open Access Journals (Sweden)

    Eric Beckett Weaver

    2016-08-01

    Full Text Available The Princip cult and what it evokes in Hungary On the 28th of June, 1914, a consumptive student, Gavrilo Princip, shot and killed prince Franz Ferdinand, the heir to the throne of the Austro-Hungarian Monarchy. The prince’s wife Sofia was also killed by a stray bullet. In the century that has passed since the assassination, the memory of Princip and the cult constructed around him has been distorted beyond recognition. As local and international politics were altered, so changed Princip’s image. The memory of Princip now evokes strong reactions not only in the South Slav lands, but in Hungary as well. In what follows, we will examine possible sources for the strong reactions evoked by Princip’s memory among Hungarians a century after his act.   Kult Principa i co on ewokuje na Węgrzech W dniu 28 czerwca 1914 roku chory na gruźlicę student Gavrilo Princip zastrzelił księcia Franciszka Ferdynanda, następcę tronu monarchii austro-węgierskiej. Od zbłąkanej kuli zginęła także żona księcia, Zofia. W okresie stulecia, które minęło od tego zabójstwa, pamięć o Principie i kult zbudowany wokół niego przeobraziły się diametralnie. Wraz z przemianami polityki lokalnej i międzynarodowej zmieniało się także postrzeganie Principa. Obecnie pamięć o Principie wywołuje silne reakcje nie tylko na ziemiach południowosłowiańskich, ale również na Węgrzech. Autor artykułu docieka, skąd mogą wypływać silne reakcje, jakie pamięć Principa wywołuje u Węgrów sto lat po jego czynie.

  11. SOMATOSENSORY EVOKED POTENTIALS IN DIABETES MELLITUS TYPE - 2

    Directory of Open Access Journals (Sweden)

    Rekha

    2015-10-01

    Full Text Available Diabetes mellitus is the most common metabolic disorder affecting majority of population. It is estimated that over 400 million people throughout the world have diabetes. It has progressed to be a pandemic from an epidemic causing morbidity and mortality in the population. Among the many complications of diabetes, diabetic neuropathies contribute majorly to the morbidity associated with the disease. Axonal conduction is affected by elevated levels of protein kinase c causing neuronal ischemia; decreased ce llular myoinositol affecting sodium potassium ATPase pump leads to decreased nerve conduction; Somatosensory E voked P otentials (SSEPs reflect the activity of somatosensory pathways mediated through the dorsal columns of the spinal cord and the specific so matosensory cortex. Recording of Somatosensory Evoked Potentials in diabetics is done to assess the sensory involvement of spinal cord. Presence of SEPs provides clear evidence for axonal continuity and by using different stimulation sites, the rate of reg eneration can be determined. Both onset and peak latencies of all SEP components are prolonged in patients with diabetes. Present study is done to compare somatosensory evoked potentials in diabetics and normal subjects. MATERIALS AND METHOD S: The present study was undertaken at the Upgraded Department of Physiology, Osmania Medical College, Koti, Hyderabad. The study was conducted on subjects, both male and female in the age group of 45 to 55 years, suffering from type II diabetes excluding other neurologi cal disorders. Non - invasive method of estimation of nerve conduction studies using SFEMG/EP — Electromyography or evoked potential system (Nicolet systems — USA using surface electrodes with automated computerized monitor attached with printer is used. RESUL TS : ANOVA showed statistically significant N9 latency (right & left sides. Latencies of all the components of SSEPs were more significant than amplitudes in Diabetic

  12. Assessment of visual disability using visual evoked potentials

    Directory of Open Access Journals (Sweden)

    Jeon Jihoon

    2012-08-01

    Full Text Available Abstract Background The purpose of this study is to validate the use of visual evoked potential (VEP to objectively quantify visual acuity in normal and amblyopic patients, and determine if it is possible to predict visual acuity in disability assessment to register visual pathway lesions. Methods A retrospective chart review was conducted of patients diagnosed with normal vision, unilateral amblyopia, optic neuritis, and visual disability who visited the university medical center for registration from March 2007 to October 2009. The study included 20 normal subjects (20 right eyes: 10 females, 10 males, ages 9–42 years, 18 unilateral amblyopic patients (18 amblyopic eyes, ages 19–36 years, 19 optic neuritis patients (19 eyes: ages 9–71 years, and 10 patients with visual disability having visual pathway lesions. Amplitude and latencies were analyzed and correlations with visual acuity (logMAR were derived from 20 normal and 18 amblyopic subjects. Correlation of VEP amplitude and visual acuity (logMAR of 19 optic neuritis patients confirmed relationships between visual acuity and amplitude. We calculated the objective visual acuity (logMAR of 16 eyes from 10 patients to diagnose the presence or absence of visual disability using relations derived from 20 normal and 18 amblyopic eyes. Results Linear regression analyses between amplitude of pattern visual evoked potentials and visual acuity (logMAR of 38 eyes from normal (right eyes and amblyopic (amblyopic eyes subjects were significant [y = −0.072x + 1.22, x: VEP amplitude, y: visual acuity (logMAR]. There were no significant differences between visual acuity prediction values, which substituted amplitude values of 19 eyes with optic neuritis into function. We calculated the objective visual acuity of 16 eyes of 10 patients to diagnose the presence or absence of visual disability using relations of y = −0.072x + 1.22 (−0.072. This resulted in a prediction

  13. Toxics Release Inventory (TRI)

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Toxics Release Inventory (TRI) is a dataset compiled by the U.S. Environmental Protection Agency (EPA). It contains information on the release and waste...

  14. Transmittance and reflectance of crystalline quartz and highand low-water content fused silica from 2 microns to 1 mm

    Science.gov (United States)

    Heaney, J. B.; Stewart, K. P.; Hass, G.

    1983-01-01

    The transmittances and reflectances of cultured crystalline quartz, Suprasil, Suprasil W, and Infrasil were compared over the wavelength region from 2 to 1000 microns. The high-water content of Suprasil and the low-water content of cultured crystalline quartz, Suprasil W, and Infrasil were determined by their transmittances measured at 2.73 microns where water content causes high absorption in optical materials. The fact that the fused silicas, both with high- and low-water content, had identical far-IR transmittances and that their transmittances were greatly inferior to that of crystalline quartz led to the conclusion that their inferior transmittance is due to their amorphous structure and not to their water content.

  15. Spontaneous activity forms a foundation for odor-evoked activation maps in the rat olfactory bulb.

    Science.gov (United States)

    Thompson, Garth J; Sanganahalli, Basavaraju G; Baker, Keeley L; Herman, Peter; Shepherd, Gordon M; Verhagen, Justus V; Hyder, Fahmeed

    2018-01-25

    Fluctuations in spontaneous activity have been observed by many neuroimaging techniques, but because these resting-state changes are not evoked by stimuli, it is difficult to determine how they relate to task-evoked activations. We conducted multi-modal neuroimaging scans of the rat olfactory bulb, both with and without odor, to examine interaction between spontaneous and evoked activities. Independent component analysis of spontaneous fluctuations revealed resting-state networks, and odor-evoked changes revealed activation maps. We constructed simulated activation maps using resting-state networks that were highly correlated to evoked activation maps. Simulated activation maps derived by intrinsic optical signal (IOS), which covers the dorsal portion of the glomerular sheet, significantly differentiated one odor's evoked activation map from the other two. To test the hypothesis that spontaneous activity of the entire glomerular sheet is relevant for representing odor-evoked activations, we used functional magnetic resonance imaging (fMRI) to map the entire glomerular sheet. In contrast to the IOS results, the fMRI-derived simulated activation maps significantly differentiated all three odors' evoked activation maps. Importantly, no evoked activation maps could be significantly differentiated using simulated activation maps produced using phase-randomized resting-state networks. Given that some highly organized resting-state networks did not correlate with any odors' evoked activation maps, we posit that these resting-state networks may characterize evoked activation maps associated with odors not studied. These results emphasize that fluctuations in spontaneous activity are relevant for active processing, signifying the relevance of resting-state mapping to functional neuroimaging. Copyright © 2018. Published by Elsevier Inc.

  16. Multimodality evoked potentials in HTLV-I associated myelopathy.

    Science.gov (United States)

    Kakigi, R; Shibasaki, H; Kuroda, Y; Endo, C; Oda, K; Ikeda, A; Hashimoto, K

    1988-08-01

    Multimodality evoked potentials (EPs) consisting of somatosensory EPs (SEPs), visual EPs (VEPs) and brainstem auditory EPs (BAEPs) were studied in 16 cases with HTLV-I associated myelopathy (HAM). Median nerve SEPs were normal in all cases. In posterior tibial nerve SEPs, the potential recorded at the 12th thoracic spinal process was normal in every case but cortical components were significantly prolonged in 10 cases, although five of these showed no sensory impairment. BAEPs were normal in every case whose hearing was intact, but VEPs were abnormal in two cases whose visual acuities were normal. The present results in HAM indicate predominant lesion in the thoracic cord, and might also suggest some subclinical lesion in the visual pathway.

  17. Temporal suppression and augmentation of click-evoked otoacoustic emissions

    DEFF Research Database (Denmark)

    Verhulst, Sarah; Harte, James; Dau, Torsten

    2008-01-01

    This study investigates temporal suppression of click-evoked otoacoustic emissions (CEOAEs), occurring when a suppressor-click is presented close in time to a test-click (e.g. 0-8ms). Various temporal suppression methods for examining temporal changes in cochlear compression were evaluated...... and measured here for seven subjects, both for short- and long-latency CEOAEs. Long-latency CEOAEs (duration >20ms) typically indicate the presence of synchronised spontaneous otoacoustic emissions (SSOAEs). Temporal suppression can only be linked to changes in CEOAE-compression if the suppressor-click affects...... the CEOAE magnitude. Phase changes induced by the suppressor-click were shown to bias suppression in two ways: (i) when a specific asymmetric measurement method was used and (ii) when synchronisation between the CEOAE and the click-stimuli was incomplete. When such biases were eliminated, temporal...

  18. Auditory evoked responses upon awakening from sleep in human subjects.

    Science.gov (United States)

    Ferrara, M; De Gennaro, L; Ferlazzo, F; Curcio, G; Barattucci, M; Bertini, M

    2001-09-14

    The hypothesis that a state of hypoarousal upon awakening should lead to a decrease in amplitude and an increase in latency of the N1-P2 components of the Auditory Evoked Potentials (AEPs) as compared to presleep wakefulness levels, was evaluated after two nocturnal awakenings and after the final morning awakening from a 7.5-h night of sleep. The amplitude of the N1-P2 complex was reduced upon awakening as compared to presleep wakefulness levels, but only following the first nocturnal awakening, scheduled after the first 2 h of sleep. This result is interpreted as indicating a link between slow wave sleep amount, mainly present during the first part of the night, and lowered levels of brain activation upon awakening. The reaction times, recorded concomitantly to AEPs, were more sensitive to the negative effects of sleep inertia.

  19. Auditory evoked field measurement using magneto-impedance sensors

    Energy Technology Data Exchange (ETDEWEB)

    Wang, K., E-mail: o-kabou@echo.nuee.nagoya-u.ac.jp; Tajima, S.; Song, D.; Uchiyama, T. [Graduate School of Engineering, Nagoya University, Nagoya (Japan); Hamada, N.; Cai, C. [Aichi Steel Corporation, Tokai (Japan)

    2015-05-07

    The magnetic field of the human brain is extremely weak, and it is mostly measured and monitored in the magnetoencephalography method using superconducting quantum interference devices. In this study, in order to measure the weak magnetic field of the brain, we constructed a Magneto-Impedance sensor (MI sensor) system that can cancel out the background noise without any magnetic shield. Based on our previous studies of brain wave measurements, we used two MI sensors in this system for monitoring both cerebral hemispheres. In this study, we recorded and compared the auditory evoked field signals of the subject, including the N100 (or N1) and the P300 (or P3) brain waves. The results suggest that the MI sensor can be applied to brain activity measurement.

  20. Facilitation and refractoriness of the electrically evoked compound action potential.

    Science.gov (United States)

    Hey, Matthias; Müller-Deile, Joachim; Hessel, Horst; Killian, Matthijs

    2017-11-01

    In this study we aim to resolve the contributions of facilitation and refractoriness at very short pulse intervals. Measurements of the refractory properties of the electrically evoked compound action potential (ECAP) of the auditory nerve in cochlear implant (CI) users at inter pulse intervals below 300 μs are influenced by facilitation and recovery effects. ECAPs were recorded using masker pulses with a wide range of current levels relative to the probe pulse levels, for three suprathreshold probe levels and pulse intervals from 13 to 200 μs. Evoked potentials were measured for 21 CI patients by using the masked response extraction artifact cancellation procedure. During analysis of the measurements the stimulation current was not used as absolute value, but in relation to the patient's individual ECAP threshold. This enabled a more general approach to describe facilitation as a probe level independent effect. Maximum facilitation was found for all tested inter pulse intervals at masker levels near patient's individual ECAP threshold, independent from probe level. For short inter pulse intervals an increased N1P1 amplitude was measured for subthreshold masker levels down to 120 CL below patient's individual ECAP threshold in contrast to the recreated state. ECAPs recorded with inter pulse intervals up to 200 μs are influenced by facilitation and recovery. Facilitation effects are most pronounced for masker levels at or below ECAP threshold, while recovery effects increase with higher masker levels above ECAP threshold. The local maximum of the ECAP amplitude for masker levels around ECAP threshold can be explained by the mutual influence of maximum facilitation and minimal refractoriness. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  1. Accuracy of measurement in electrically evoked compound action potentials.

    Science.gov (United States)

    Hey, Matthias; Müller-Deile, Joachim

    2015-01-15

    Electrically evoked compound action potentials (ECAP) in cochlear implant (CI) patients are characterized by the amplitude of the N1P1 complex. The measurement of evoked potentials yields a combination of the measured signal with various noise components but for ECAP procedures performed in the clinical routine, only the averaged curve is accessible. To date no detailed analysis of error dimension has been published. The aim of this study was to determine the error of the N1P1 amplitude and to determine the factors that impact the outcome. Measurements were performed on 32 CI patients with either CI24RE (CA) or CI512 implants using the Software Custom Sound EP (Cochlear). N1P1 error approximation of non-averaged raw data consisting of recorded single-sweeps was compared to methods of error approximation based on mean curves. The error approximation of the N1P1 amplitude using averaged data showed comparable results to single-point error estimation. The error of the N1P1 amplitude depends on the number of averaging steps and amplification; in contrast, the error of the N1P1 amplitude is not dependent on the stimulus intensity. Single-point error showed smaller N1P1 error and better coincidence with 1/√(N) function (N is the number of measured sweeps) compared to the known maximum-minimum criterion. Evaluation of N1P1 amplitude should be accompanied by indication of its error. The retrospective approximation of this measurement error from the averaged data available in clinically used software is possible and best done utilizing the D-trace in forward masking artefact reduction mode (no stimulation applied and recording contains only the switch-on-artefact). Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Can Treadmill Perturbations Evoke Stretch Reflexes in the Calf Muscles?

    Directory of Open Access Journals (Sweden)

    Lizeth H Sloot

    Full Text Available Disinhibition of reflexes is a problem amongst spastic patients, for it limits a smooth and efficient execution of motor functions during gait. Treadmill belt accelerations may potentially be used to measure reflexes during walking, i.e. by dorsal flexing the ankle and stretching the calf muscles, while decelerations show the modulation of reflexes during a reduction of sensory feedback. The aim of the current study was to examine if belt accelerations and decelerations of different intensities applied during the stance phase of treadmill walking can evoke reflexes in the gastrocnemius, soleus and tibialis anterior in healthy subjects. Muscle electromyography and joint kinematics were measured in 10 subjects. To determine whether stretch reflexes occurred, we assessed modelled musculo-tendon length and stretch velocity, the amount of muscle activity, as well as the incidence of bursts or depressions in muscle activity with their time delays, and co-contraction between agonist and antagonist muscle. Although the effect on the ankle angle was small with 2.8±1.0°, the perturbations caused clear changes in muscle length and stretch velocity relative to unperturbed walking. Stretched muscles showed an increasing incidence of bursts in muscle activity, which occurred after a reasonable electrophysiological time delay (163-191 ms. Their amplitude was related to the muscle stretch velocity and not related to co-contraction of the antagonist muscle. These effects increased with perturbation intensity. Shortened muscles showed opposite effects, with a depression in muscle activity of the calf muscles. The perturbations only slightly affected the spatio-temporal parameters, indicating that normal walking was retained. Thus, our findings showed that treadmill perturbations can evoke reflexes in the calf muscles and tibialis anterior. This comprehensive study could form the basis for clinical implementation of treadmill perturbations to functionally

  3. Light-evoked S-nitrosylation in the retina

    Science.gov (United States)

    Tooker, Ryan E; Vigh, Jozsef

    2015-01-01

    Nitric oxide (NO) synthesis in the retina is triggered by light stimulation. NO has been shown to modulate visual signal processing at multiple sites in the vertebrate retina, via activation of the most sensitive target of NO signaling, soluble guanylate cyclase. NO can also alter protein structure and function and exert biological effects directly by binding to free thiol groups of cysteine residues in a chemical reaction called S-nitrosylation. However, in the central nervous system, including the retina, this reaction has not been considered to be significant under physiological conditions. Here we provide immunohistochemical evidence for extensive S-nitrosylation that takes place in the goldfish and mouse retinas under physiologically relevant light intensities, in an intensity-dependent manner, with a strikingly similar pattern in both species. Pre-treatment with NEM, which occludes S-nitrosylation, or with TRIM, an inhibitor of neuronal NO synthase, eliminated the light-evoked increase in S-nitrosylated protein immunofluorescence (SNI) in the retinas of both species. Similarly, light did not increase SNI, above basal levels, in retinas of transgenic mice lacking neuronal NO synthase. Qualitative analysis of the light-adapted mouse retina with mass spectrometry revealed more than 300 proteins that were S-nitrosylated upon illumination, many of which are known to participate directly in retinal signal processing. Our data strongly suggest that in the retina, light-evoked NO production leads to extensive S-nitrosylation and that this process is a significant post-translational modification affecting a wide range of proteins under physiological conditions. PMID:25823749

  4. EFFECT OF SMOKING ON TRASIENTLY EVOKED OTOACOUSTIC EMISSION.

    Science.gov (United States)

    Gegenava, Kh; Japaridze, Sh; Sharashenidze, N; Jalabadze, G; Kevanishvili, Z

    2016-01-01

    Evoked otoacoustic emissions, EOAEs, are proved to be sounds aroused in response to external acoustic stimulus by the cochlear outer hair cells. Transiently evoked otoacoustic emissions, TEOAEs, are the most clinically utilized EOAEs. TEOAEs are detectable in 98% of people with normal hearing, regardless of age or sex, while two ears of any individual produce similar TEOAEs waveforms. The objective of the presented study was the comparison of TEOAE magnitudes in cigarette smokers and nonsmokers. The TEOAE occurrence and characteristics in individuals of both samples with audiometrically proved hearing losses and in those without were also specifically examined. 30 smokers and and 30 nonsmokers within the age range of 30-59 years were involved in the present study after informed concent. OAEs were performed to each subject by Madsen Capella's-OAE/middle ear analyzer-GN Otometrics, (Danmark). After OAE testing each subject was performed routine pure-tone audiometry and tympanometry. Obtained results were statistically treated by the student's t-distribution. According to our results 76.6% of smokers and 3.33% of nonsmokers had marked different level decrease in TEOAE amplitude. Audiographic measurments showed altered audiogram in 6.7% of smokers and in 3.33% of nonsmokers. Based on the above mentioned results we suppose that smoking has significant influence on hearing function, especially on cochlear apparatus; At the same time, TOEAE, as a sensitive method can be used for very early detection of hearing loss, even when there are neither any subjective complains nor some changies on audiogram.

  5. Light-evoked S-nitrosylation in the retina.

    Science.gov (United States)

    Tooker, Ryan E; Vigh, Jozsef

    2015-10-01

    Nitric oxide (NO) synthesis in the retina is triggered by light stimulation. NO has been shown to modulate visual signal processing at multiple sites in the vertebrate retina, via activation of the most sensitive target of NO signaling, soluble guanylate cyclase. NO can also alter protein structure and function and exert biological effects directly by binding to free thiol groups of cysteine residues in a chemical reaction called S-nitrosylation. However, in the central nervous system, including the retina, this reaction has not been considered to be significant under physiological conditions. Here we provide immunohistochemical evidence for extensive S-nitrosylation that takes place in the goldfish and mouse retinas under physiologically relevant light intensities, in an intensity-dependent manner, with a strikingly similar pattern in both species. Pretreatment with N-ethylmaleimide (NEM), which occludes S-nitrosylation, or with 1-(2-trifluromethylphenyl)imidazole (TRIM), an inhibitor of neuronal NO synthase, eliminated the light-evoked increase in S-nitrosylated protein immunofluorescence (SNI) in the retinas of both species. Similarly, light did not increase SNI, above basal levels, in retinas of transgenic mice lacking neuronal NO synthase. Qualitative analysis of the light-adapted mouse retina with mass spectrometry revealed more than 300 proteins that were S-nitrosylated upon illumination, many of which are known to participate directly in retinal signal processing. Our data strongly suggest that in the retina light-evoked NO production leads to extensive S-nitrosylation and that this process is a significant posttranslational modification affecting a wide range of proteins under physiological conditions. © 2015 Wiley Periodicals, Inc.

  6. Munc-18-1 Regulates the Initial Release Rate of Exocytosis

    OpenAIRE

    Barclay, Jeff W.

    2008-01-01

    Carbon fiber amperometry is a popular method for measuring single exocytotic events; however, the functional interpretation of the data can prove hazardous. For example, changes to vesicle transmitter levels can appear to cause changes in the timing and rate of the fusion process itself. Use of an analytical technique based on differentiation revealed that an increase in dense-core granule catecholamine content by exogenous application of l-DOPA did not affect initial release rates. Changes t...

  7. Sex and Ear Differences in Spontaneous and Click-Evoked Otoacoustic Emissions in Young Adults

    Science.gov (United States)

    Snihur, Adrian W. K.; Hampson, Elizabeth

    2011-01-01

    Effects of sex and handedness on the production of spontaneous and click-evoked otoacoustic emissions (OAEs) were explored in a non-hearing impaired population (ages 17-25 years). A sex difference in OAEs, either produced spontaneously (spontaneous OAEs or SOAEs) or in response to auditory stimuli (click-evoked OAEs or CEOAEs) has been reported in…

  8. The Nature and Process of Development in Averaged Visually Evoked Potentials: Discussion on Pattern Structure.

    Science.gov (United States)

    Izawa, Shuji; Mizutani, Tohru

    This paper examines the development of visually evoked EEG patterns in retarded and normal subjects. The paper focuses on the averaged visually evoked potentials (AVEP) in the central and occipital regions of the brain in eyes closed and eyes open conditions. Wave pattern, amplitude, and latency are examined. The first section of the paper reviews…

  9. One Year of Musical Training Affects Development of Auditory Cortical-Evoked Fields in Young Children

    Science.gov (United States)

    Fujioka, Takako; Ross, Bernhard; Kakigi, Ryusuke; Pantev, Christo; Trainor, Laurel J.

    2006-01-01

    Auditory evoked responses to a violin tone and a noise-burst stimulus were recorded from 4- to 6-year-old children in four repeated measurements over a 1-year period using magnetoencephalography (MEG). Half of the subjects participated in musical lessons throughout the year; the other half had no music lessons. Auditory evoked magnetic fields…

  10. Long-term visuo-gustatory appetitive and aversive conditioning potentiate human visual evoked potentials

    DEFF Research Database (Denmark)

    Christoffersen, Gert R.J.; Laugesen, Jakob L.; Møller, Per

    2017-01-01

    and aversive visuo-gustatory conditioning were studied with high density EEG-recordings focusing on late components in the visual evoked potentials (VEPs), specifically the N2-P3 waves. Unfamiliar images were paired with either a pleasant or an unpleasant juice and VEPs evoked by the images were compared...

  11. The effect of changes in perilymphatic K+ on the vestibular evoked potential in the guinea pig

    NARCIS (Netherlands)

    Kingma, C. M.; Wit, H. P.

    2010-01-01

    To investigate the effect on the functioning of the vestibular system of a rupture of Reissner's membrane, artificial endolymph was injected in scala media of ten guinea pigs and vestibular evoked potentials (VsEPs), evoked by vertical acceleration pulses, were measured. Directly after injection of

  12. Gender differences in rival characteristics that evoke jealousy in response to emotional versus sexual infidelity

    NARCIS (Netherlands)

    Buunk, Abraham (Bram); Dijkstra, Pieternel

    2004-01-01

    Previous research has shown that in men jealousy is evoked more by a rival's status-related characteristics than in women, whereas in women jealousy is evoked more by a rival's physical attractiveness than in men. The present study examined whether the occurrence of this gender difference depends

  13. Long-Term Visuo-Gustatory Appetitive and Aversive Conditioning Potentiate Human Visual Evoked Potentials

    DEFF Research Database (Denmark)

    Christoffersen, Gert Rene Juul; Laugesen, Jakob Lund; Møller, Per

    2017-01-01

    and aversive visuo-gustatory conditioning were studied with high density EEG-recordings focusing on late components in the visual evoked potentials (VEPs), specifically the N2-P3 waves. Unfamiliar images were paired with either a pleasant or an unpleasant juice and VEPs evoked by the images were compared...

  14. Changes in ultraviolet transmittance of hydrogel and silicone-hydrogel contact lenses induced by wear.

    Science.gov (United States)

    Osuagwu, Uchechukwu L; Ogbuehi, Kelechi C; Almubrad, Turki M

    2014-01-01

    To evaluate the ultraviolet (UV) transmittance spectra of different contact lenses and assess the effect of wear on UV transmittance values and ocular protection factor (PF). Transmittance in the UV range (200-400 nm) of 216 contact lenses was measured before and after wear, using a spectrophotometer. The contact lenses used were ACUVUE TruEye, ACUVUE MOIST, ACUVUE OASYS, ACUVUE 2, ACUVUE DEFINE, DAILIES AquaComfort Plus, AIR OPTIX for astigmatism, FreshLook ONE-DAY lens, and Neo Cosmo. This study indicates that the following contact lenses transmitted less than the American National Standards Institute (ANSI) of 5% or less of UVB: ACUVUE DEFINE, ACUVUE MOIST, ACUVUE 2, ACUVUE TruEye, and ACUVUE OASYS. All lenses also met the ANSI standard of less than 30% transmittance of UVA except for AquaComfort Plus, AIR OPTIX for astigmatism, and Neo Cosmo. FreshLook meets the UVA transmission standard but fell short of the UVB transmission standard by 3%. FreshLook and ACUVUE MOIST had the highest calculated PF (3.9) of the hydrogel group and were unaffected after wear. Of the silicone-hydrogels (SiHs), the PF for AIR OPTIX for astigmatism was the highest (10.6) before wear and increased after wear to a PF of 13.3. The results also show that, for the UVC region, significant differences exist in transmittance values before and after wear of all SiH lenses and all hydrogel lenses, except for Neo Cosmo. FreshLook and Neo Cosmo were the only lenses that showed no statistically significant differences in the UVA transmittance after wear. Ultraviolet-blocking contact lenses were effective in blocking ultraviolet radiation to safe levels recommended by ANSI, whereas non-UV blockers such as AquaComfort Plus and AIR OPTIX for astigmatism also showed UV-attenuation capabilities greater than the values previously reported. The Neo Cosmo contact lens transmitted greater than 86% UVB and 89% UVA, making it unsuitable for UV protection seekers. Transmission is modified after contact lens

  15. Relationship between presynaptic membrane potential and acetylcholine release in synaptosomes from Torpedo electric organ.

    Science.gov (United States)

    Meunier, F M

    1984-01-01

    The membrane potential of purely cholinergic synaptosomes isolated from Torpedo electric organ was monitored with fluorescent carbocyanine dyes. An increased fluorescence was associated with depolarization and a quenching with hyperpolarization. Fluorescence data provided evidence that Torpedo synaptosomes have a membrane potential mainly driven by a K+ diffusion potential and a membrane potential of about -50 mV could be estimated after calibration of fluorescence signals with ionophore antibiotics. The release of acetylcholine (ACh) from Torpedo synaptosomes was monitored continuously by measuring the light emitted by a chemiluminescent method (Israël & Lesbats, 1981 a). Using fluorescence data, the release of ACh was expressed as a function of membrane potential. The relationship between presynaptic potential and transmitter release as determined by biochemical methods at cholinergic nerve endings showed striking similarities to that observed at the squid giant synapse. Several substances were also tested with regard to their depolarizing and releasing properties and it was found that the toxin isolated from the venom of the annelid Glycera convoluta, which induced a large increase in quantal release of transmitter (Manaranche, Thieffry, & Israël, 1980) promoted a depolarization of Torpedo synaptosomes in addition to ACh release. PMID:6207289

  16. The involuntary nature of music-evoked autobiographical memories in Alzheimer's disease.

    Science.gov (United States)

    El Haj, Mohamad; Fasotti, Luciano; Allain, Philippe

    2012-03-01

    The main objective of this paper was to examine the involuntary nature of music-evoked autobiographical memories. For this purpose, young adults, older adults, and patients with a clinical diagnosis of probable Alzheimer's disease (AD) were asked to remember autobiographical events in two conditions: after being exposed to their own chosen music, and in silence. Compared to memories evoked in silence, memories evoked in the "Music" condition were found to be more specific, accompanied by more emotional content and impact on mood, and retrieved faster. In addition, these memories engaged less executive processes. Thus, with all these characteristics and the fact that they are activated by a perceptual cue (i.e., music), music-evoked autobiographic memories have all the features to be considered as involuntary memories. Our paper reveals several characteristics of music-evoked autobiographical memories in AD patients and offers a theoretical background for this phenomenon. Copyright © 2012 Elsevier Inc. All rights reserved.

  17. Dorsal root activity evoked by stimulation of vagina-cervix-uterus junction in the rat.

    Science.gov (United States)

    Tovar, Anibal; Lara-Garcia, Miguel; Cruz, Yolanda; Pacheco, Pablo

    2013-02-16

    In the present study, we characterized the evoked electrical activity from T(13) to S(2) dorsal roots (DRs) during glass probe-stimulation of the vagina-cervix-uterus junction (VCUJ) of female Wistar rats. The results showed that gentle stimulation of VCUJ evoked high-amplitude electrical activity in L(3) and L(6) DRs. Hypogastric or pelvic nerve transection failed to abolish this activity. L(6)-S(1) spinal trunk transection abolished the high-amplitude electrical activity evoked in L(6) DR, while transection of the lumbosacral trunk blocked the high-amplitude electrical activity evoked in L(3) DR. These data suggest that during copulation, penile intromission likely activates the low-threshold sensory receptors of the VCUJ, thereby evoking sensory neural activity that enters the spinal cord via L(3) and L(6) dorsal roots, whose axons travel through the lumbosacral trunk and pudendal nerve. Copyright © 2013. Published by Elsevier B.V.

  18. Asynchronous presynaptic glutamate release enhances neuronal excitability during the post-spike refractory period.

    Science.gov (United States)

    Iremonger, Karl J; Bains, Jaideep S

    2016-02-15

    Many excitatory synapses in the brain release glutamate with both synchronous and asynchronous components. Immediately following an action potential, neurons display a reduced excitability due to the post-spike afterhyperpolarization (AHP). This gives rise to a relative refractory period. When an action potential is evoked by glutamate synaptic input possessing asynchronous release, the delayed glutamate release events act to depolarize the neuron during the AHP and overcome the relative refractory period. These results demonstrate a new role for asynchronous release in regulating post-spike excitability and the relative refractory period in central neurons. Post-spike afterhyperpolarizations (AHPs) functionally inhibit neuronal excitability for tens to hundreds of milliseconds following each action potential. This imposes a relative refractory period during which synaptic excitation is less effective at evoking spikes. Here we asked whether some synapses have mechanisms in place that allow them to overcome the AHP and drive spiking in target cells during this period of reduced excitability. We examined glutamate synapses onto oxytocin and vasopressin neurons in the paraventricular nucleus of the hypothalamus. These synapses can display pronounced asynchronous glutamate release following a single presynaptic spike, with the time course of release being similar to that of the post-spike AHP. To test whether asynchronous release is more effective at overcoming the relative refractory period, we evoked a single action potential with either a brief synchronous depolarization or an asynchronous potential and then assessed excitability at multiple time points following the spike. Neurons receiving asynchronous depolarizing synaptic inputs had a shorter relative refractory period than those receiving synchronous depolarizations. Our data demonstrate that synapses releasing glutamate in an asynchronous and delayed manner are ideally adapted to counter the AHP. By

  19. Multicomponent Implant Releasing Dexamethasone

    Science.gov (United States)

    Nikkola, L.; Vapalahti, K.; Ashammakhi, N.

    2008-02-01

    Several inflammatory conditions are usually treated with corticosteroids. There are various problems like side effects with traditional applications of steroids, e.g. topical, or systemic routes. Local drug delivery systems have been studied and developed to gain more efficient administration with fewer side effects. Earlier, we reported on developing Dexamethasone (DX) releasing biodegradable fibers. However, their drug release properties were not satisfactory in terms of onset of drug release. Thus, we assessed the development of multicomponent (MC) implant to enhance earlier drug release from such biodegradable fibers. Poly (lactide-co-glycolide) (PLGA) and 2 wt-% and 8 wt-% DX were compounded and extruded with twin-screw extruder to form of fibers. Some of the fibers were sterilized to obtain a change in drug release properties. Four different fiber classes were studied: 2 wt-%, 8 wt-%, sterilized 2 wt-%, and sterilized 8 wt-%. 3×4 different DX-releasing fibers were then heat-pressed to form one multicomponent rod. Half of the rods where sterilized. Drug release was measured from initial fibers and multicomponent rods using a UV/VIS spectrometer. Shear strength and changes in viscosity were also measured. Drug release studies showed that drug release commenced earlier from multicomponent rods than from component fibers. Drug release from multicomponent rods lasted from day 30 to day 70. The release period of sterilized rods extended from day 23 to day 57. When compared to the original component fibers, the drug release from MC rods commenced earlier. The initial shear strength of MC rods was 135 MPa and decreased to 105 MPa during four weeks of immersion in phosphate buffer solution. Accordingly, heat pressing has a positive effect on drug release. After four weeks in hydrolysis, no disintegration was observed.

  20. 47 CFR 95.217 - (R/C Rule 17) May I operate my R/C station transmitter by remote control?

    Science.gov (United States)

    2010-10-01

    ... records. See R/C Rule 24, § 95.224. (c) Remote control means operation of an R/C transmitter from any place other than the location of the R/C transmitter. Direct mechanical control or direct electrical control by wire from some point on the same premises, craft or vehicles as the R/C transmitter is not...