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Sample records for afferent depolarization pad

  1. Effects of changing skin mechanics on the differential sensitivity to surface compliance by tactile afferents in the human finger pad.

    PubMed

    Hudson, Kathryn M; Condon, Melia; Ackerley, Rochelle; McGlone, Francis; Olausson, Håkan; Macefield, Vaughan G; Birznieks, Ingvars

    2015-10-01

    It is not known how changes in skin mechanics affect the responses of cutaneous mechanoreceptors in the finger pads to compression forces. We used venous occlusion to change the stiffness of the fingers and investigated whether this influenced the firing of low-threshold mechanoreceptors to surfaces of differing stiffness. Unitary recordings were made from 10 slowly adapting type I (SAI), 10 fast adapting type I (FAI) and 9 slowly adapting type II (SAII) units via tungsten microelectrodes inserted into the median nerve at the wrist. A servo-controlled stimulator applied ramp-and-hold forces (1, 2, and 4 N) at a constant loading and unloading rate (2 N/s) via a flat 2.5-cm-diameter silicone disk over the center of the finger pad. Nine silicone disks (objects), varying in compliance, were used. Venous occlusion, produced by inflating a sphygmomanometer cuff around the upper arm to 40 ± 5 mmHg, was used to induce swelling of the fingers and increase the compliance of the finger pulp. Venous occlusion had no effect on the firing rates of the SAI afferents, nor on the slopes of the relationship between mean firing rate and object compliance at each amplitude, but did significantly reduce the slopes for the FAI afferents. Although the SAII afferents possess a poor capacity to encode changes in object compliance, mean firing rates were significantly lower during venous occlusion. The finding that venous occlusion had no effect on the firing properties of SAI afferents indicates that these afferents preserve their capacity to encode changes in object compliance, despite changes in skin mechanics. PMID:26269550

  2. Pad TPC

    SciTech Connect

    Hilke, H.J.

    1984-01-01

    A new kind of TPC is described, in which no sense wires exist but gas amplification is obtained from a single parallel gap. A mesh separates the drift volume from the amplifying gap. The anode is segmented into circular rows of narrow pads for rphi measurement by centroid finding and into wide circular pads for dE/dx sampling. The expected advantages of this technique are: better, track angle independent rphi resolution (no need for wire pulse height corrections); better two-track separation if more electronic channels can be afforded; less dead space from frame structures; reduced positive feedback and slower chamber deterioration by deposit formation on the anode. Very tight construction tolerances are the principle drawback. The properties of the Pad TPC are discussed in view of large scale construction and first test results are presented.

  3. Compartmental modeling of rat macular primary afferents from three-dimensional reconstructions of transmission electron micrographs of serial sections.

    PubMed

    Chimento, T C; Doshay, D G; Ross, M D

    1994-05-01

    1. We cut serial sections through the medial part of the rat vestibular macula for transmission electron microscopic (TEM) examination, computer-assisted three-dimensional (3-D) reconstruction, and compartmental modeling. The ultrastructural research showed that many primary vestibular neurons have an unmyelinated segment, often branched, that extends between the heminode [putative site of the spike initiation zone (SIZ)] and the expanded terminal(s) (calyx, calyces). These segments, termed the neuron branches, and the calyces frequently have spinelike processes of various dimensions that morphologically are afferent, efferent, or reciprocal to other macular neural elements. The purpose of this research was to determine whether morphometric data obtained ultrastructurally were essential to compartmental models [i.e., they influenced action potential (AP) generation, latency, or amplitude] or whether afferent parts could be collapsed into more simple units without markedly affecting results. We used the compartmental modeling program NEURON for this research. 2. In the first set of simulations we studied the relative importance of small variations in process morphology on distant depolarization. A process was placed midway along an isolated piece of a passive neuron branch. The dimensions of the four processes corresponded to actual processes in the serial sections. A synapse, placed on the head of each process, was activated and depolarization was recorded at the end of the neuron branch. When we used 5 nS synaptic conductance, depolarization varied by 3 mV. In a systematic study over a representative range of stem dimensions, depolarization varied by 15.7 mV. Smaller conductances produced smaller effects. Increasing membrane resistivity from 5,000 to 50,000 omega cm2 had no significant effect. 3. In a second series of simulations, using whole primary afferents, we examined the combined effects of process location and afferent morphology on depolarization magnitude

  4. Modulation of vagal afferent excitation and reduction of food intake by leptin and cholecystokinin.

    PubMed

    Peters, James H; Simasko, Steven M; Ritter, Robert C

    2006-11-30

    The gut-peptide, cholecystokinin (CCK), reduces food intake by acting at CCK-1 receptors on vagal afferent neurons, whereas the feeding effects of the adipokine hormone, leptin, are associated primarily with its action on receptors (ObRb) in the hypothalamus. Recently, however, ObRb mRNA has been reported in vagal afferent neurons, some of which also express CCK-1 receptor, suggesting that leptin, alone or in cooperation with CCK, might activate vagal afferent neurons, and influence food intake via a vagal route. To evaluate these possibilities we have been examining the cellular and behavioral effects of leptin and CCK on vagal afferent neurons. In cultured vagal afferent neurons leptin and CCK evoked short latency, transient depolarizations, often leading to action potentials, and increases in cytosolic calcium. There was a much higher prevalence of CCK and leptin sensitivity amongst cultured vagal afferent neurons that innervate stomach or duodenum than there was in the overall vagal afferent population. Furthermore, almost all leptin-responsive gastric and duodenal vagal afferents also were sensitive to CCK. Leptin, infused into the upper GI tract arterial supply, reduced meal size, and enhanced satiation evoked by CCK. These results indicate that vagal afferent neurons are activated by leptin, and that this activation is likely to participate in meal termination, perhaps by enhancing vagal sensitivity to CCK. Our findings are consistent with the view that leptin and CCK exert their influence on food intake by accessing multiple neural systems (viscerosensory, motivational, affective and motor) at multiple points along the neuroaxis. PMID:16872644

  5. Polarization-independent electro-optic depolarizer

    NASA Astrophysics Data System (ADS)

    Heismann, F.; Tokuda, K. L.

    1995-05-01

    We demonstrate a compact electro-optic polarization scrambler that depolarizes arbitrarily polarized light with less than 2.5% residual degree of polarization and variable depolarization times in the microsecond to millisecond range. The integrated-optic depolarizer is fabricated on lithium niobate and operates with a single-mode waveguide designed for a 1.5- mu m wavelength. The scrambler introduces negligible intensity modulation of less than 1.6% in the depolarized output light.

  6. Functional dopamine D2 receptors on rat vagal afferent neurones.

    PubMed Central

    Lawrence, A J; Krstew, E; Jarrott, B

    1995-01-01

    1. In the present study in vitro electrophysiology and receptor autoradiography were used to determine whether rat vagal afferent neurones possess dopamine D2 receptors. 2. Dopamine (10-300 microM) elicited a temperature- and concentration-dependent depolarization of the rat isolated nodose ganglion preparation. When applied to the tissue 15 min prior to agonist, raclopride (10 microM), clozapine (10 microM) or a mixture of raclopride and clozapine (10 microM each) all produced a threefold parallel shift to the right of the dopamine concentration-response curve. In contrast, SCH 23390 (100 nM), phentolamine and propranolol (1 microM each) failed to antagonize the dopamine-mediated depolarization. 3. [125I]-NCQ 298 (0.5 nM), a D2 selective radioligand, bound topographically to sections of rat brainstem. Densitometric quantification of autoradiograms revealed 93.8 +/- 0.5% specific binding of this salicylamide radioligand, as determined by raclopride (10 microM, n = 10 animals). Binding was highest in the nucleus tractus solitarius (NTS), particularly the medial and gelatinous subnuclei. In addition, specific binding was also observed in the interpolar spinal trigeminal nucleus and the inferior olive. 4. Unilateral nodose ganglionectomy caused a 36.6 +/- 3.0% reduction in specific binding in the denervated NTS compared to the contralateral NTS. Furthermore, the loss of binding was confined to the dorsal aspect of the medial subnucleus of the NTS. Sham surgery had no effect on the binding of [125I]-NCQ 298 in rat brainstem. 5. The present data provide evidence for the presence of functionally relevant dopamine D2 receptors on both the soma and central terminals of rat vagal afferent neurones.(ABSTRACT TRUNCATED AT 250 WORDS) Images Figure 3 PMID:7606337

  7. Peripheral Artery Disease (PAD)

    MedlinePlus

    ... changes and medication . View an animation of atherosclerosis Atherosclerosis and PAD Atherosclerosis is a disease in which plaque builds up ... of an artery. PAD is usually caused by atherosclerosis in the peripheral arteries (or outer regions away ...

  8. Geometry of generalized depolarizing channels

    SciTech Connect

    Burrell, Christian K.

    2009-10-15

    A generalized depolarizing channel acts on an N-dimensional quantum system to compress the 'Bloch ball' in N{sup 2}-1 directions; it has a corresponding compression vector. We investigate the geometry of these compression vectors and prove a conjecture of Dixit and Sudarshan [Phys. Rev. A 78, 032308 (2008)], namely, that when N=2{sup d} (i.e., the system consists of d qubits), and we work in the Pauli basis then the set of all compression vectors forms a simplex. We extend this result by investigating the geometry in other bases; in particular we find precisely when the set of all compression vectors forms a simplex.

  9. Utricular afferents: morphology of peripheral terminals

    PubMed Central

    Huwe, J. A.; Logan, G. J.; Williams, B.; Rowe, M. H.

    2015-01-01

    The utricle provides critical information about spatiotemporal properties of head movement. It comprises multiple subdivisions whose functional roles are poorly understood. We previously identified four subdivisions in turtle utricle, based on hair bundle structure and mechanics, otoconial membrane structure and hair bundle coupling, and immunoreactivity to calcium-binding proteins. Here we ask whether these macular subdivisions are innervated by distinctive populations of afferents to help us understand the role each subdivision plays in signaling head movements. We quantified the morphology of 173 afferents and identified six afferent classes, which differ in structure and macular locus. Calyceal and dimorphic afferents innervate one striolar band. Bouton afferents innervate a second striolar band; they have elongated terminals and the thickest processes and axons of all bouton units. Bouton afferents in lateral (LES) and medial (MES) extrastriolae have small-diameter axons but differ in collecting area, bouton number, and hair cell contacts (LES >> MES). A fourth, distinctive population of bouton afferents supplies the juxtastriola. These results, combined with our earlier findings on utricular hair cells and the otoconial membrane, suggest the hypotheses that MES and calyceal afferents encode head movement direction with high spatial resolution and that MES afferents are well suited to signal three-dimensional head orientation and striolar afferents to signal head movement onset. PMID:25632074

  10. α(5)GABA(A) receptors mediate primary afferent fiber tonic excitability in the turtle spinal cord.

    PubMed

    Loeza-Alcocer, Emanuel; Canto-Bustos, Martha; Aguilar, Justo; González-Ramírez, Ricardo; Felix, Ricardo; Delgado-Lezama, Rodolfo

    2013-11-01

    γ-Amino butyric acid (GABA) plays a key role in the regulation of central nervous system by activating synaptic and extrasynaptic GABAA receptors. It is acknowledged that extrasynaptic GABAA receptors located in the soma, dendrites, and axons may be activated tonically by low extracellular GABA concentrations. The activation of these receptors produces a persistent conductance that can hyperpolarize or depolarize nerve cells depending on the Cl(-) equilibrium potential. In an in vitro preparation of the turtle spinal cord we show that extrasynaptic α5GABAA receptors mediate the tonic state of excitability of primary afferents independently of the phasic primary afferent depolarization mediated by synaptic GABAA receptors. Blockade of α5GABAA receptors with the inverse agonist L-655,708 depressed the dorsal root reflex (DRR) without affecting the phasic increase in excitability of primary afferents. Using RT-PCR and Western blotting, we corroborated the presence of the mRNA and the α5GABAA protein in the dorsal root ganglia of the turtle spinal cord. The receptors were localized in primary afferents in dorsal root, dorsal root ganglia, and peripheral nerve terminals using immunoconfocal microscopy. Considering the implications of the DRR in neurogenic inflammation, α5GABAA receptors may serve as potential pharmacological targets for the treatment of pain. PMID:23966669

  11. Peripheral oxytocin activates vagal afferent neurons to suppress feeding in normal and leptin-resistant mice: a route for ameliorating hyperphagia and obesity.

    PubMed

    Iwasaki, Yusaku; Maejima, Yuko; Suyama, Shigetomo; Yoshida, Masashi; Arai, Takeshi; Katsurada, Kenichi; Kumari, Parmila; Nakabayashi, Hajime; Kakei, Masafumi; Yada, Toshihiko

    2015-03-01

    Oxytocin (Oxt), a neuropeptide produced in the hypothalamus, is implicated in regulation of feeding. Recent studies have shown that peripheral administration of Oxt suppresses feeding and, when infused subchronically, ameliorates hyperphagic obesity. However, the route through which peripheral Oxt informs the brain is obscure. This study aimed to explore whether vagal afferents mediate the sensing and anorexigenic effect of peripherally injected Oxt in mice. Intraperitoneal Oxt injection suppressed food intake and increased c-Fos expression in nucleus tractus solitarius to which vagal afferents project. The Oxt-induced feeding suppression and c-Fos expression in nucleus tractus solitarius were blunted in mice whose vagal afferent nerves were blocked by subdiaphragmatic vagotomy or capsaicin treatment. Oxt induced membrane depolarization and increases in cytosolic Ca(2+) concentration ([Ca(2+)]i) in single vagal afferent neurons. The Oxt-induced [Ca(2+)]i increases were markedly suppressed by Oxt receptor antagonist. These Oxt-responsive neurons also responded to cholecystokinin-8 and contained cocaine- and amphetamine-regulated transcript. In obese diabetic db/db mice, leptin failed to increase, but Oxt increased [Ca(2+)]i in vagal afferent neurons, and single or subchronic infusion of Oxt decreased food intake and body weight gain. These results demonstrate that peripheral Oxt injection suppresses food intake by activating vagal afferent neurons and thereby ameliorates obesity in leptin-resistant db/db mice. The peripheral Oxt-regulated vagal afferent neuron provides a novel target for treating hyperphagia and obesity. PMID:25540101

  12. Aberrations of a horizontal-vertical depolarizer

    NASA Technical Reports Server (NTRS)

    Mcclain, Stephen C.; Chipman, Russell A.; Hillman, Lloyd W.

    1992-01-01

    Ray-trace equations for uniaxial birefringent materials are used here to derive third-order estimates for aberrations that are produced in imaging through uniaxial plates and horizontal-vertical (HV) depolarizers. An HV depolarizer is a spatial pseudodepolarizer; it converts a uniform input polarization state into a continuum of spatially varying polarization states in an output beam. An HV depolarizer consists of two birefringent wedges whose crystal axes are crossed at 90 deg. The interface between the wedges is included, which leads to a spatially varying retardance that provides the spatial pseudodepolarization. In HV depolarizers, spherical aberration, astigmatism, and image doubling are the principal aberrations for on-axis objects. Only spherical aberration occurs in isotropic plates, while the presence of birefringent wedges introduces astigmatism and image doubling. It is shown that image separation is proportional to the magnitude of the retardance variation.

  13. Fundus depolarization imaging with GDx VCC scanning laser polarimeter and depolarization characteristics of normal eyes

    NASA Astrophysics Data System (ADS)

    Zhou, Qienyuan; Leder, Henry A.; Lo, Barrick P.; Reed, Geradus C.; Knighton, Robert W.; Cousins, Scott W.

    2009-02-01

    GDx VCC is a confocal scanning laser polarimeter (SLP) developed to assess the retinal nerve fiber layer (RNFL) of the eye based on measurement of the phase retardation in the backscattered light from the fundus. In addition to the phase retardation measurement, a depolarization measurement is readily available from the same image series. We hypothesize that the depolarized light in the GDx signal consists of backscattering from the retinal pigment epithelium (RPE) and the RPE-Bruch's membrane junction, and further, that subRPE deposits contribute to the depolarized backscattered light in proportion to their thickness. Therefore, a quantitative macular depolarization map will provide information about both spatial distribution and heterogeneity of the RPE structure and deposit thickness. Ultimately we predict that depolarization mapping will significantly increase the positive predictive power to identify early dry AMD eyes. In this paper, depolarization measurements in normal eyes and age related changes are reported. Data collection was performed at the Duke University Eye Center. A commercial GDx VCC system was modified with a central fixation target and, instead of depolarized light intensity images, normalized depolarization images were derived and saved in the database. Macular depolarization was observed to increase with age in normal eyes at a rate of 0.27%/yr.

  14. PAD_AUDIT -- PAD Auditing Package

    NASA Astrophysics Data System (ADS)

    Clayton, C. A.

    The PAD (Packet Assembler Disassembler) utility is the part of the VAX/VMS Coloured Book Software (CBS) which allows a user to log onto remote computers from a local VAX. Unfortunately, logging into a computer via either the Packet SwitchStream (PSS) or the International Packet SwitchStream (IPSS) costs real money. Some users either do not appreciate this or do not care and have been known to clock up rather large quarterly bills. This software package allows a system manager to determine who has used PAD to call where and (most importantly) how much it has cost. The system manager can then take appropriate action - either charging the individuals, warning them to use the facility with more care or even denying access to a greedy user to one or more sites.

  15. Pad 39B Deconstruction

    NASA Video Gallery

    A time-lapse video of the deconstruction of Launch Pad 39B at NASA's Kennedy Space Center in Florida. The fixed service structure and rotating service structure were removed. Both structures were b...

  16. Follistatin-like 1 suppresses sensory afferent transmission by activating Na+,K+-ATPase.

    PubMed

    Li, Kai-Cheng; Zhang, Fang-Xiong; Li, Chang-Lin; Wang, Feng; Yu, Ming-Yan; Zhong, Yan-Qing; Zhang, Kai-Hua; Lu, Ying-Jin; Wang, Qiong; Ma, Xiao-Li; Yao, Jun-Ru; Wang, Jin-Yuan; Lin, Li-Bo; Han, Mei; Zhang, Yu-Qiu; Kuner, Rohini; Xiao, Hua-Sheng; Bao, Lan; Gao, Xiang; Zhang, Xu

    2011-03-10

    Excitatory synaptic transmission is modulated by inhibitory neurotransmitters and neuromodulators. We found that the synaptic transmission of somatic sensory afferents can be rapidly regulated by a presynaptically secreted protein, follistatin-like 1 (FSTL1), which serves as a direct activator of Na(+),K(+)-ATPase (NKA). The FSTL1 protein is highly expressed in small-diameter neurons of the dorsal root ganglion (DRG). It is transported to axon terminals via small translucent vesicles and secreted in both spontaneous and depolarization-induced manners. Biochemical assays showed that FSTL1 binds to the α1 subunit of NKA and elevates NKA activity. Extracellular FSTL1 induced membrane hyperpolarization in cultured cells and inhibited afferent synaptic transmission in spinal cord slices by activating NKA. Genetic deletion of FSTL1 in small DRG neurons of mice resulted in enhanced afferent synaptic transmission and sensory hypersensitivity, which could be reduced by intrathecally applied FSTL1 protein. Thus, FSTL1-dependent activation of NKA regulates the threshold of somatic sensation. PMID:21382556

  17. Superoxide enhances Ca2+ entry through L-type channels in the renal afferent arteriole.

    PubMed

    Vogel, Paul A; Yang, Xi; Moss, Nicholas G; Arendshorst, William J

    2015-08-01

    Reactive oxygen species regulate cardiovascular and renal function in health and disease. Superoxide participates in acute calcium signaling in afferent arterioles and renal vasoconstriction produced by angiotensin II, endothelin, thromboxane, and pressure-induced myogenic tone. Known mechanisms by which superoxide acts include quenching of nitric oxide and increased ADP ribosyl cyclase/ryanodine-mediated calcium mobilization. The effect(s) of superoxide on other calcium signaling pathways in the renal microcirculation is poorly understood. The present experiments examined the acute effect of superoxide generated by paraquat on calcium entry pathways in isolated rat afferent arterioles. The peak increase in cytosolic calcium concentration caused by KCl (40 mmol/L) was 99±14 nmol/L. The response to this membrane depolarization was mediated exclusively by L-type channels because it was abolished by nifedipine but was unaffected by the T-type channel blocker mibefradil. Paraquat increased superoxide production (dihydroethidium fluorescence), tripled the peak response to KCl to 314±68 nmol/L (P<0.001) and doubled the plateau response. These effects were abolished by tempol and nitroblue tetrazolium, but not by catalase, confirming actions of superoxide and not of hydrogen peroxide. Unaffected by paraquat and superoxide was calcium entry through store-operated calcium channels activated by thapsigargin-induced calcium depletion of sarcoplasmic reticular stores. Also unresponsive to paraquat was ryanodine receptor-mediated calcium-induced calcium release from the sarcoplasmic reticulum. Our results provide new evidence that superoxide enhances calcium entry through L-type channels activated by membrane depolarization in rat cortical afferent arterioles, without affecting calcium entry through store-operated entry or ryanodine receptor-mediated calcium mobilization. PMID:26034201

  18. Relative entropy convergence for depolarizing channels

    NASA Astrophysics Data System (ADS)

    Müller-Hermes, Alexander; Stilck França, Daniel; Wolf, Michael M.

    2016-02-01

    We study the convergence of states under continuous-time depolarizing channels with full rank fixed points in terms of the relative entropy. The optimal exponent of an upper bound on the relative entropy in this case is given by the log-Sobolev-1 constant. Our main result is the computation of this constant. As an application, we use the log-Sobolev-1 constant of the depolarizing channels to improve the concavity inequality of the von Neumann entropy. This result is compared to similar bounds obtained recently by Kim and we show a version of Pinsker's inequality, which is optimal and tight if we fix the second argument of the relative entropy. Finally, we consider the log-Sobolev-1 constant of tensor-powers of the completely depolarizing channel and use a quantum version of Shearer's inequality to prove a uniform lower bound.

  19. Zinc depolarized electrochemical CO2 concentration

    NASA Technical Reports Server (NTRS)

    Woods, R. R.; Marshall, R. D.; Schubert, F. H.

    1975-01-01

    Two zinc depolarized electrochemical carbon dioxide concentrator concepts were analytically and experimentally evaluated for portable life support system carbon dioxide (CO2) removal application. The first concept, referred to as the zinc hydrogen generator electrochemical depolarized CO2 concentrator, uses a ZHG to generate hydrogen for direct use in an EDC. The second concept, referred to as the zinc/electrochemical depolarized concentrator, uses a standard EDC cell construction modified for use with the Zn anode. The Zn anode is consumed and subsequently regenerated, thereby eliminating the need to supply H2 to the EDC for the CO2 removal process. The evaluation was based primarily on an analytical evaluation of the two ZnDCs at projected end item performance and hardware design levels. Both ZnDC concepts for PLSS CO2 removal application were found to be noncompetitive in both total equivalent launch weight and individual extravehicular activity mission volume when compared to other candidate regenerable PLSS CO2 scrubbers.

  20. Localization of nerve depolarization with magnetic stimulation.

    PubMed

    Odderson, I R; Halar, E M

    1992-06-01

    The specific location on the magnetic stimulation (MS) coil that may correspond to the area of nerve depolarization has not been determined. In order to localize such an area, MS with 9-cm and 5-cm diameter coils was compared with conventional percutaneous electric stimulation (ES). On the 9-cm coil the distribution of points of nerve depolarization corresponded to that quarter of the coil which was placed over and parallel to the median nerve, whereas on the 5-cm coil, this area also extended outside the coil. The points of median nerve depolarization with MS were distributed over a distance of 7 cm on the stimulator head and was nearly identical for the 2 coil sizes at the wrist and elbow. Ulnar nerve costimulation was less frequent with the smaller coil at the wrist. A calculated reference point on the coil is suggested for more accurate NCV determinations. PMID:1508235

  1. Afferent Connectivity of the Zebrafish Habenulae

    PubMed Central

    Turner, Katherine J.; Hawkins, Thomas A.; Yáñez, Julián; Anadón, Ramón; Wilson, Stephen W.; Folgueira, Mónica

    2016-01-01

    The habenulae are bilateral nuclei located in the dorsal diencephalon that are conserved across vertebrates. Here we describe the main afferents to the habenulae in larval and adult zebrafish. We observe afferents from the subpallium, nucleus rostrolateralis, posterior tuberculum, posterior hypothalamic lobe, median raphe; we also see asymmetric afferents from olfactory bulb to the right habenula, and from the parapineal to the left habenula. In addition, we find afferents from a ventrolateral telencephalic nucleus that neurochemical and hodological data identify as the ventral entopeduncular nucleus (vENT), confirming and extending observations of Amo et al. (2014). Fate map and marker studies suggest that vENT originates from the diencephalic prethalamic eminence and extends into the lateral telencephalon from 48 to 120 hour post-fertilization (hpf). No afferents to the habenula were observed from the dorsal entopeduncular nucleus (dENT). Consequently, we confirm that the vENT (and not the dENT) should be considered as the entopeduncular nucleus “proper” in zebrafish. Furthermore, comparison with data in other vertebrates suggests that the vENT is a conserved basal ganglia nucleus, being homologous to the entopeduncular nucleus of mammals (internal segment of the globus pallidus of primates) by both embryonic origin and projections, as previously suggested by Amo et al. (2014). PMID:27199671

  2. Vestibular afferent responses to microrotational stimuli

    NASA Technical Reports Server (NTRS)

    Myers, Steven F.; Lewis, Edwin R.

    1991-01-01

    Intracellular microelectrode recording/labeling techniques were used to investigate vestibular afferent responses in the bullfrog, to very small amplitude (less than 5 deg p-p) sinusoidal rotations in the vertical plane over the frequency range of 0.063-4 Hz. Robust responses to peak accelerations as low as 0.031 deg/sec per sec were obtained from units subsequently traced to either the central portion of the anterior canal crista or the striolar region of the utricle. All of these microrotationally sensitive afferent neurons had irregular resting discharge rates, and the majority had transfer ratios (relative to rotational velocity) of 1-40 spikes/sec per deg/sec. Individual utricular afferent velocity transfer ratios were nearly constant over the frequency range of 0.125-4 Hz. Canal units displayed decreasing response transfer ratios as stimulus frequencies increased. These findings indicate that, although utricular striolar and central crista afferent velocity transfer ratios to microrotations were very similar, utricular striolar afferent neurons were more faithful sensors of very small amplitude rotational velocity in the vertical plane.

  3. Capturing Depolarization Information in GPS Reflections

    NASA Technical Reports Server (NTRS)

    Kelly, Kenneth C.

    2000-01-01

    The state of the surface of the ocean has a prominent effect on the depolarization of the circularly polarized emissions of the GPS satellites. The system designers election to capture the important information carries with it the need to implement the data extraction in a cost efficient manner. Antenna components, and associated networks for deriving depolarization information are described. For typical sea states the polarization characteristics of the reflected GPS signal vary rapidly with time so various methods for recording the changes are discussed.

  4. About Peripheral Artery Disease (PAD)

    MedlinePlus

    ... changes and medication . View an animation of atherosclerosis Atherosclerosis and PAD Atherosclerosis is a disease in which plaque builds up ... of an artery. PAD is usually caused by atherosclerosis in the peripheral arteries (or outer regions away ...

  5. Treating P.A.D.

    MedlinePlus

    ... Home Current Issue Past Issues Special Section Treating P.A.D. Past Issues / Summer 2008 Table of ... is diminished. Illustration courtesy of NHLBI Treatment for P.A.D. is designed to reduce a patient's ...

  6. Treating P.A.D.

    MedlinePlus

    ... Issue Past Issues Special Section Treating P.A.D. Past Issues / Summer 2008 Table of Contents For ... Illustration courtesy of NHLBI Treatment for P.A.D. is designed to reduce a patient's symptoms, prevent ...

  7. Neuroanatomy of extrinsic afferents supplying the gastrointestinal tract.

    PubMed

    Berthoud, H R; Blackshaw, L A; Brookes, S J H; Grundy, D

    2004-04-01

    Here we discuss the neuroanatomy of extrinsic gastrointestinal (GI) afferent neurones, the relationship between structure and function and the role of afferents in disease. Three pathways connect the gut to the central nervous system: vagal afferents signal mainly from upper GI regions, pelvic afferents mainly from the colorectal region and splanchnic afferents from throughout. Vagal afferents mediate reflex regulation of gut function and behaviour, operating mainly at physiological levels. There are two major functional classes - tension receptors, responding to muscular contraction and distension, and mucosal receptors. The function of vagal endings correlates well with their anatomy: tracing studies show intramuscular arrays (IMAs) and intraganglionic laminar endings (IGLEs); IGLEs are now known to respond to tension. Functional mucosal receptors correlate with endings traced to the lamina propria. Pelvic afferents serve similar functions to vagal afferents, and additionally mediate both innocuous and noxious sensations. Splanchnic afferents comprise mucosal and stretch-sensitive afferents with low thresholds in addition to high-threshold serosal/mesenteric afferents suggesting diverse roles. IGLEs, probably of pelvic origin, have been identified recently in the rectum and respond similarly to gastric vagal IGLEs. Gastrointestinal afferents may be sensitized or inhibited by chemical mediators released from several cell types. Whether functional changes have anatomical correlates is not known, but it is likely that they underlie diseases involving visceral hypersensitivity. PMID:15066001

  8. Whisker-related afferents in superior colliculus.

    PubMed

    Castro-Alamancos, Manuel A; Favero, Morgana

    2016-05-01

    Rodents use their whiskers to explore the environment, and the superior colliculus is part of the neural circuits that process this sensorimotor information. Cells in the intermediate layers of the superior colliculus integrate trigeminotectal afferents from trigeminal complex and corticotectal afferents from barrel cortex. Using histological methods in mice, we found that trigeminotectal and corticotectal synapses overlap somewhat as they innervate the lower and upper portions of the intermediate granular layer, respectively. Using electrophysiological recordings and optogenetics in anesthetized mice in vivo, we showed that, similar to rats, whisker deflections produce two successive responses that are driven by trigeminotectal and corticotectal afferents. We then employed in vivo and slice experiments to characterize the response properties of these afferents. In vivo, corticotectal responses triggered by electrical stimulation of the barrel cortex evoke activity in the superior colliculus that increases with stimulus intensity and depresses with increasing frequency. In slices from adult mice, optogenetic activation of channelrhodopsin-expressing trigeminotectal and corticotectal fibers revealed that cells in the intermediate layers receive more efficacious trigeminotectal, than corticotectal, synaptic inputs. Moreover, the efficacy of trigeminotectal inputs depresses more strongly with increasing frequency than that of corticotectal inputs. The intermediate layers of superior colliculus appear to be tuned to process strong but infrequent trigeminal inputs and weak but more persistent cortical inputs, which explains features of sensory responsiveness, such as the robust rapid sensory adaptation of whisker responses in the superior colliculus. PMID:26864754

  9. Contractile properties of afferent and efferent arterioles.

    PubMed

    Ito, S; Abe, K

    1997-07-01

    1. The balance of vascular tone of the afferent and efferent arteriole is a crucial determinant of glomerular haemodynamics. Despite their intimate anatomical relationship in the juxtaglomerular apparatus, the mechanisms that regulate afferent and efferent arteriolar tone are different. 2. In the afferent arteriole, two intrinsic mechanisms, the myogenic response and macula densa-mediated tubuloglomerular feedback (TGF) play a dominant role, maintaining the glomerular filtration rate (GFR) at a constant level over a wide range of renal perfusion pressure. Studies have shown that these two mechanisms are modulated by nitric oxide (NO). In addition, an interaction between TGF and angiotensin II (AngII) seems to be essential to maintaining GFR despite large variations in daily intake of salt and water. 3. In the efferent arteriole, neither myogenic response nor TGF seems to be important, while AngII is one major factor involved in the control of vascular resistance. In addition, recent studies have provided evidence that NO and prostaglandins produced by the glomerulus may control resistance of the downstream efferent arteriole. 4. As the early segment of the efferent arteriole resides within the glomerulus, various autacoid hormones produced by the glomerulus may reach and directly act on this segment, thereby controlling the glomerular capillary pressure. Thus, it would be important to understand the differences in the mechanisms operating at the afferent and efferent arteriole, as well as their alterations in various physiological and pathological conditions. PMID:9248673

  10. Inelastic spin depolarization spectroscopy in silicon

    NASA Astrophysics Data System (ADS)

    Li, Jing; Appelbaum, Ian

    2013-07-01

    In ballistic injection spin transport devices, a tunnel junction emitter bias voltage determines the energy at which spin-polarized hot electrons cross a Schottky barrier into the conduction band of a semiconductor collector. Fast energy relaxation via phonon emission restores equilibrium for subsequent transport at the band edge. Through an analysis incorporating voltage-dependent measurement of magnetocurrent polarization in silicon spin transport devices along with magnetic-tunnel- and spin-valve-transistor configurations, the contribution to total spin depolarization caused by this inelastic scattering in the presence of spin-orbit interaction is quantified. From the shape of this spectroscopy, it is found that all measured spin depolarization can be accounted for solely by considering spin relaxation during bulk transport in quasi-equilibrium near the conduction band edge; the relaxation of initial spin state is irrelevant to the spin-dependent device characteristics.

  11. Ultracold neutron depolarization in magnetic bottles

    NASA Astrophysics Data System (ADS)

    Steyerl, A.; Kaufman, C.; Müller, G.; Malik, S. S.; Desai, A. M.

    2012-12-01

    We analyze the depolarization of ultracold neutrons confined in a magnetic field configuration similar to those used in existing or proposed magnetogravitational storage experiments aiming at a precise measurement of the neutron lifetime. We use an extension of the semiclassical Majorana approach as well as an approximate quantum mechanical analysis, both pioneered by Walstrom [Nucl. Instrum. Methods Phys. Res. A10.1016/j.nima.2008.11.010 599, 82 (2009)]. In contrast with this previous work we do not restrict the analysis to purely vertical modes of neutron motion. The lateral motion is shown to cause the predominant depolarization loss in a magnetic storage trap. The system studied also allowed us to estimate the depolarization loss suffered by ultracold neutrons totally reflected on a nonmagnetic mirror immersed in a magnetic field. This problem is of preeminent importance in polarized neutron decay studies such as the measurement of the asymmetry parameter A using ultracold neutrons, and it may limit the efficiency of ultracold neutron polarizers based on passage through a high magnetic field.

  12. Compton effect thermally activated depolarization dosimeter

    DOEpatents

    Moran, Paul R.

    1978-01-01

    A dosimetry technique for high-energy gamma radiation or X-radiation employs the Compton effect in conjunction with radiation-induced thermally activated depolarization phenomena. A dielectric material is disposed between two electrodes which are electrically short circuited to produce a dosimeter which is then exposed to the gamma or X radiation. The gamma or X-radiation impinging on the dosimeter interacts with the dielectric material directly or with the metal composing the electrode to produce Compton electrons which are emitted preferentially in the direction in which the radiation was traveling. A portion of these electrons becomes trapped in the dielectric material, consequently inducing a stable electrical polarization in the dielectric material. Subsequent heating of the exposed dosimeter to the point of onset of ionic conductivity with the electrodes still shorted through an ammeter causes the dielectric material to depolarize, and the depolarization signal so emitted can be measured and is proportional to the dose of radiation received by the dosimeter.

  13. Trafficking of Na+/Ca2+ exchanger to the site of persistent inflammation in nociceptive afferents.

    PubMed

    Scheff, Nicole N; Gold, Michael S

    2015-06-01

    Persistent inflammation results in an increase in the amplitude and duration of depolarization-evoked Ca(2+) transients in putative nociceptive afferents. Previous data indicated that these changes were the result of neither increased neuronal excitability nor an increase in the amplitude of depolarization. Subsequent data also ruled out an increase in voltage-gated Ca(2+) currents and recruitment of Ca(2+)-induced Ca(2+) release. Parametric studies indicated that the inflammation-induced increase in the duration of the evoked Ca(2+) transient required a relatively large and long-lasting increase in the concentration of intracellular Ca(2+) implicating the Na(+)/Ca(2+) exchanger (NCX), a major Ca(2+) extrusion mechanism activated with high intracellular Ca(2+) loads. The contribution of NCX to the inflammation-induced increase in the evoked Ca(2+) transient in rat sensory neurons was tested using fura-2 AM imaging and electrophysiological recordings. Changes in NCX expression and protein were assessed with real-time PCR and Western blot analysis, respectively. An inflammation-induced decrease in NCX activity was observed in a subpopulation of putative nociceptive neurons innervating the site of inflammation. The time course of the decrease in NCX activity paralleled that of the inflammation-induced changes in nociceptive behavior. The change in NCX3 in the cell body was associated with a decrease in NCX3 protein in the ganglia, an increase in the peripheral nerve (sciatic) yet no change in the central root. This single response to inflammation is associated with changes in at least three different segments of the primary afferent, all of which are likely to contribute to the dynamic response to persistent inflammation. PMID:26041911

  14. Pain processing by spinal microcircuits: afferent combinatorics.

    PubMed

    Prescott, Steven A; Ratté, Stéphanie

    2012-08-01

    Pain, itch, heat, cold, and touch represent different percepts arising from somatosensory input. How stimuli give rise to these percepts has been debated for over a century. Recent work supports the view that primary afferents are highly specialized to transduce and encode specific stimulus modalities. However, cross-modal interactions (e.g. inhibition or exacerbation of pain by touch) support convergence rather than specificity in central circuits. We outline how peripheral specialization together with central convergence could enable spinal microcircuits to combine inputs from distinctly specialized, co-activated afferents and to modulate the output signals thus formed through computations like normalization. These issues will be discussed alongside recent advances in our understanding of microcircuitry in the superficial dorsal horn. PMID:22409855

  15. Ischemia-induced spreading depolarization in the retina.

    PubMed

    Srienc, Anja I; Biesecker, Kyle R; Shimoda, Angela M; Kur, Joanna; Newman, Eric A

    2016-09-01

    Cortical spreading depolarization is a metabolically costly phenomenon that affects the brain in both health and disease. Following severe stroke, subarachnoid hemorrhage, or traumatic brain injury, cortical spreading depolarization exacerbates tissue damage and enlarges infarct volumes. It is not known, however, whether spreading depolarization also occurs in the retina in vivo. We report now that spreading depolarization episodes are generated in the in vivo rat retina following retinal vessel occlusion produced by photothrombosis. The properties of retinal spreading depolarization are similar to those of cortical spreading depolarization. Retinal spreading depolarization waves propagate at a velocity of 3.0 ± 0.1 mm/min and are associated with a negative shift in direct current potential, a transient cessation of neuronal spiking, arteriole constriction, and a decrease in tissue O2 tension. The frequency of retinal spreading depolarization generation in vivo is reduced by administration of the NMDA antagonist MK-801 and the 5-HT(1D) agonist sumatriptan. Branch retinal vein occlusion is a leading cause of vision loss from vascular disease. Our results suggest that retinal spreading depolarization could contribute to retinal damage in acute retinal ischemia and demonstrate that pharmacological agents can reduce retinal spreading depolarization frequency after retinal vessel occlusion. Blocking retinal spreading depolarization generation may represent a therapeutic strategy for preserving vision in branch retinal vein occlusion patients. PMID:27389181

  16. Postsynaptic Depolarization Enhances GABA Drive to Dorsomedial Hypothalamic Neurons through Somatodendritic Cholecystokinin Release.

    PubMed

    Crosby, Karen M; Baimoukhametova, Dinara V; Bains, Jaideep S; Pittman, Quentin J

    2015-09-23

    Somatodendritically released peptides alter synaptic function through a variety of mechanisms, including autocrine actions that liberate retrograde transmitters. Cholecystokinin (CCK) is a neuropeptide expressed in neurons in the dorsomedial hypothalamic nucleus (DMH), a region implicated in satiety and stress. There are clear demonstrations that exogenous CCK modulates food intake and neuropeptide expression in the DMH, but there is no information on how endogenous CCK alters synaptic properties. Here, we provide the first report of somatodendritic release of CCK in the brain in male Sprague Dawley rats. CCK is released from DMH neurons in response to repeated postsynaptic depolarizations, and acts in an autocrine fashion on CCK2 receptors to enhance postsynaptic NMDA receptor function and liberate the retrograde transmitter, nitric oxide (NO). NO subsequently acts presynaptically to enhance GABA release through a soluble guanylate cyclase-mediated pathway. These data provide the first demonstration of synaptic actions of somatodendritically released CCK in the hypothalamus and reveal a new form of retrograde plasticity, depolarization-induced potentiation of inhibition. Significance statement: Somatodendritic signaling using endocannabinoids or nitric oxide to alter the efficacy of afferent transmission is well established. Despite early convincing evidence for somatodendritic release of neurohypophysial peptides in the hypothalamus, there is only limited evidence for this mode of release for other peptides. Here, we provide the first evidence for somatodendritic release of the satiety peptide cholecystokinin (CCK) in the brain. We also reveal a new form of synaptic plasticity in which postsynaptic depolarization results in enhancement of inhibition through the somatodendritic release of CCK. PMID:26400945

  17. Blockage of vibrissae afferents: I. Motor effects.

    PubMed

    Prchal, A; Albarracín, A L; Décima, E E

    2004-02-01

    In the past, it has been proposed that the rat vibrissae play an important role in other hand, postural abnormalities, muscle tone decreases and hypomotility after sensory organ destructions were proposed as evidence supporting the "level setting" or "tonic" hypothesis. This hypothesis postulates that afferent activity, besides its well know transductive functions, sets the excitability state of the central nervous system. We thought the vibrissal system to be a good model to dissect these two postulated roles because vibrissae trimming would annul the transductive function without affecting the integrity of nerve activity. Thus we compare the effects of trimming the whiskers with blocking the vibrissal afferent nerves on two types of motor behavior: activity in an open field and walking over a rope connecting two elevated platforms. We found that only vibrissal afferent blockage (both nerve section and local anaesthesia) produced severe failures in the motor performances studied. These effects could not be fully explained by the abolition of the vibrissae as a sensory modality because cutting the whiskers did not significantly affect the motor performance. These data are discussed in reference to a tonic or general excitatory function of sensory inputs upon the central nervous system. PMID:15143620

  18. Dynamic depolarization in plasmonic metal nanoparticles

    NASA Astrophysics Data System (ADS)

    Apell, S. Peter; Zorić, Igor; Langhammer, Christoph

    2016-08-01

    At very low photon energies most metals have a very large and negative dielectric function. For the response of a metal nanoparticle to an external field in this limit, this means that the particular choice of metal does not matter and the localized surface plasmon energy mainly depends on the shape and size of the particle. Here, we present a theoretical framework to describe this situation and unearth the interplay between the depolarization factor of the problem at hand and the dielectric function of the particle. Available experimental results compare favorably with our theoretical framework.

  19. Tune space manipulations in jumping depolarizing resonances

    SciTech Connect

    Ratner, L.G.; Ahrens, L.A.

    1987-01-01

    In February 1986, the AGS polarized beam reached a momentum of 22 GeV/c with a 45% polarization and an intensity of 1 to 2 x 10/sup 10/ polarized protons per pulse at a repetition rate of 2.1 seconds. In order to achieve this, one had to overcome the effect of some 40 depolarizing resonances. In our first commissioning run in 1984, we had reached 16.5 GeV/c using, with suitable modifications, the conventional techniques first used at the Argonne ZGS. This worked well, but we found that the fast tune shifts required to cross the intrinsic depolarizing resonances were causing an increase in beam emittance which led to the need for stronger corrections later in the cycle and to diminished extraction efficiency. For the 1986 run, we were prepared to minimize this emittance growth by the application of slow quadrupole pulses to change the region in tune space in which we operated the first tune quads. In this paper we give a brief description of the conventional corrections, but our main emphasis is on the descriptions of tune space manipulations.

  20. Afferent innervation patterns of the saccule in pigeons

    NASA Technical Reports Server (NTRS)

    Zakir, M.; Huss, D.; Dickman, J. D.

    2003-01-01

    The innervation patterns of vestibular saccular afferents were quantitatively investigated in pigeons using biotinylated dextran amine as a neural tracer and three-dimensional computer reconstruction. Type I hair cells were found throughout a large portion of the macula, with the highest density observed in the striola. Type II hair cells were located throughout the macula, with the highest density in the extrastriola. Three classes of afferent innervation patterns were observed, including calyx, dimorph, and bouton units, with 137 afferents being anatomically reconstructed and used for quantitative comparisons. Calyx afferents were located primarily in the striola, innervated a number of type I hair cells, and had small innervation areas. Most calyx afferent terminal fields were oriented parallel to the anterior-posterior axis and the morphological polarization reversal line. Dimorph afferents were located throughout the macula, contained fewer type I hair cells in a calyceal terminal than calyx afferents and had medium sized innervation areas. Bouton afferents were restricted to the extrastriola, with multi-branching fibers and large innervation areas. Most of the dimorph and bouton afferents had innervation fields that were oriented dorso-ventrally but were parallel to the neighboring reversal line. The organizational morphology of the saccule was found to be distinctly different from that of the avian utricle or lagena otolith organs and appears to represent a receptor organ undergoing evolutionary adaptation toward sensing linear motion in terrestrial and aerial species.

  1. Nanomolar Oxytocin Synergizes with Weak Electrical Afferent Stimulation to Activate the Locomotor CPG of the Rat Spinal Cord In Vitro

    PubMed Central

    Dose, Francesco; Zanon, Patrizia; Coslovich, Tamara; Taccola, Giuliano

    2014-01-01

    Synergizing the effect of afferent fibre stimulation with pharmacological interventions is a desirable goal to trigger spinal locomotor activity, especially after injury. Thus, to better understand the mechanisms to optimize this process, we studied the role of the neuropeptide oxytocin (previously shown to stimulate locomotor networks) on network and motoneuron properties using the isolated neonatal rat spinal cord. On motoneurons oxytocin (1 nM–1 μM) generated sporadic bursts with superimposed firing and dose-dependent depolarization. No desensitization was observed despite repeated applications. Tetrodotoxin completely blocked the effects of oxytocin, demonstrating the network origin of the responses. Recording motoneuron pool activity from lumbar ventral roots showed oxytocin mediated depolarization with synchronous bursts, and depression of reflex responses in a stimulus and peptide-concentration dependent fashion. Disinhibited bursting caused by strychnine and bicuculline was accelerated by oxytocin whose action was blocked by the oxytocin antagonist atosiban. Fictive locomotion appeared when subthreshold concentrations of NMDA plus 5HT were coapplied with oxytocin, an effect prevented after 24 h incubation with the inhibitor of 5HT synthesis, PCPA. When fictive locomotion was fully manifested, oxytocin did not change periodicity, although cycle amplitude became smaller. A novel protocol of electrical stimulation based on noisy waveforms and applied to one dorsal root evoked stereotypic fictive locomotion. Whenever the stimulus intensity was subthreshold, low doses of oxytocin triggered fictive locomotion although oxytocin per se did not affect primary afferent depolarization evoked by dorsal root pulses. Among the several functional targets for the action of oxytocin at lumbar spinal cord level, the present results highlight how small concentrations of this peptide could bring spinal networks to threshold for fictive locomotion in combination with other

  2. Improved Helmet-Padding Material

    NASA Technical Reports Server (NTRS)

    Dawn, Frederic S.; Weiss, Fred R.; Eck, John D.

    1994-01-01

    Polyimide foamed into lightweight padding material for use in helmets. Exhibits increased resistance to ignition, combustion, and impact, and it outgasses less. Foam satisfies offgassing and toxicity requirements of NASA/JSC criteria (NHB80601B). Helmets containing this improved padding material used by firefighters, police, offshore drilling technicians, construction workers, miners, and race-car drivers.

  3. A 20 Ghz Depolarization Experiment Using the ATS-6 Satellite

    NASA Technical Reports Server (NTRS)

    Bostian, C. W.; Manus, E. A.; Marshall, R. E.; Pendrak, H. N.; Stutzman, W. L.; Wiley, P. H.; Kauffman, S. R.

    1975-01-01

    A depolarization experiment using the 20 GHz downlink from the ATS-6 satellite was described. The following subjects were covered: (1) an operational summary of the experiment, (2) a description of the equipment used with emphasis on improvements made to the signal processing receiver used with the ATS-5 satellite, (3) data on depolarization and attenuation in one snow storm and two rain storms at 45 deg elevation, (4) data on low angle propagation, (5) conclusions about depolarization on satellite paths, and (6) recommendations for the depolarization portion of the CTS experiment.

  4. Relative Contributions of Afferent Vagal Fibers to Resistance to Diet-Induced Obesity

    PubMed Central

    Stearns, A. T.; Balakrishnan, A.; Radmanesh, A.; Ashley, S. W.; Rhoads, D. B.

    2014-01-01

    Background We previously demonstrated vagal neural pathways, specifically subdiaphragmatic afferent fibers, regulate expression of the intestinal sodium-glucose cotransporter SGLT1, the intestinal transporter responsible for absorption of dietary glucose. We hypothesized targeting this pathway could be a novel therapy for obesity. We therefore tested the impact of disrupting vagal signaling by total vagotomy or selective vagal de-afferentation on weight gain and fat content in diet-induced obese rats. Methods Male Sprague–Dawley rats (n = 5–8) underwent truncal vagotomy, selective vagal de-afferentation with capsaicin, or sham procedure. Animals were maintained for 11 months on a high-caloric Western diet. Abdominal visceral fat content was assessed by magnetic resonance imaging together with weight of fat pads at harvest. Glucose homeostasis was assessed by fasting blood glucose and HbA1C. Jejunal SGLT1 gene expression was assessed by qPCR and immunoblotting and function by glucose uptake in everted jejunal sleeves. Results At 11-months, vagotomized rats weighed 19% less (P = 0.003) and de-afferented rats 7% less (P = 0.19) than shams. Vagotomized and de-afferented animals had 52% (P < 0.0001) and 18% reduction (P = 0.039) in visceral abdominal fat, respectively. There were no changes in blood glucose or glycemic indexes. SGLT1 mRNA, protein and function were unchanged across all cohorts at 11-months postoperatively. Conclusions Truncal vagotomy led to significant reductions in both diet-induced weight gain and visceral abdominal fat deposition. Vagal de-afferentation led to a more modest, but clinically and statistically significant, reduction in visceral abdominal fat. As increased visceral abdominal fat is associated with excess morbidity and mortality, vagal de-afferentation may be a useful adjunct in bariatric surgery. PMID:22138962

  5. Valley depolarization in monolayer WSe2

    PubMed Central

    Yan, Tengfei; Qiao, Xiaofen; Tan, Pingheng; Zhang, Xinhui

    2015-01-01

    We have systematically examined the circular polarization of monolayer WSe2 at different temperature, excitation energy and exciton density. The valley depolarization in WSe2 is experimentally confirmed to be governed by the intervalley electron-hole exchange interaction. More importantly, a non-monotonic dependence of valley circular polarization on the excitation power density has been observed, providing the experimental evidence for the non-monotonic dependence of exciton intervalley scattering rate on the excited exciton density. The physical origination of our experimental observations has been proposed to be in analogy to the D′yakonov-Perel′ mechanism that is operative in conventional GaAs quantum well systems. Our experimental results are fundamentally important for well understanding the valley pseudospin relaxation in atomically thin transition metal dichalcogenides. PMID:26490157

  6. Valley depolarization in monolayer WSe2.

    PubMed

    Yan, Tengfei; Qiao, Xiaofen; Tan, Pingheng; Zhang, Xinhui

    2015-01-01

    We have systematically examined the circular polarization of monolayer WSe2 at different temperature, excitation energy and exciton density. The valley depolarization in WSe2 is experimentally confirmed to be governed by the intervalley electron-hole exchange interaction. More importantly, a non-monotonic dependence of valley circular polarization on the excitation power density has been observed, providing the experimental evidence for the non-monotonic dependence of exciton intervalley scattering rate on the excited exciton density. The physical origination of our experimental observations has been proposed to be in analogy to the D'yakonov-Perel' mechanism that is operative in conventional GaAs quantum well systems. Our experimental results are fundamentally important for well understanding the valley pseudospin relaxation in atomically thin transition metal dichalcogenides. PMID:26490157

  7. Dual-Mode Adhesive Pad

    NASA Technical Reports Server (NTRS)

    Hartz, Leslie

    1994-01-01

    Tool helps worker grip and move along large, smooth structure with no handgrips or footholds. Adheres to surface but easily released by actuating simple mechanism. Includes handle and segmented contact-adhesive pad. Bulk of pad made of soft plastic foam conforming to surface of structure. Each segment reinforced with rib. In sticking mode, ribs braced by side catches. In peeling mode, side catches retracted, and segmented adhesive pad loses its stiffness. Modified versions useful in inspecting hulls of ships and scaling walls in rescue operations.

  8. Simple analytic formula for the strength of spin depolarizing resonance

    SciTech Connect

    Lee, S.Y.

    1985-01-01

    A simple analytic formula is derived to explain the periodicity of spin depolarizing resonance. The spin depolarizing resonance strengths of CPS and SPS at CERN and the lattices of meson factory at TRIUMF are used to compare with the analytic formula.

  9. [Cortical spreading depolarization: a new pathophysiological mechanism in neurological diseases].

    PubMed

    Sánchez-Porras, Renán; Robles-Cabrera, Adriana; Santos, Edgar

    2014-05-20

    Cortical spreading depolarization is a wave of almost complete depolarization of the neuronal and glial cells that occurs in different neurological diseases such as migraine with aura, subarachnoid hemorrhage, intracerebral hemorrhage, head trauma and stroke. These depolarization waves are characterized by a change in the negative potential with an amplitude between -10 and -30mV, duration of ∼1min and changes in the ion homeostasis between the intra- and extracellular space. This results in neuronal edema and dendritic distortion. Under pathologic states of hypoperfusion, cortical spreading depolarization can produce oxidative stress, worsen hypoxia and induce neuronal death. This is due to intense arterial vasoconstriction produced by an inverse response called spreading ischemia. Only in the last years there has been an electrophysiological confirmation of cortical spreading depolarization in human brains. Occurrence of cortical spreading depolarization has been associated with worse outcome in patients. Currently, increased knowledge regarding the pathophysiologic mechanisms supports the hypothetical correlation of cortical spreading depolarization with brain damage in humans. There are diverse therapeutic alternatives that promise inhibition of cortical spreading depolarization and subsequent better outcomes. PMID:23928069

  10. Response properties of pigeon otolith afferents to linear acceleration

    NASA Technical Reports Server (NTRS)

    Si, X.; Angelaki, D. E.; Dickman, J. D.

    1997-01-01

    In the present study, the sensitivity to sinusoidal linear accelerations in the plane of the utricular macula was tested in afferents. The head orientation relative to the translation axis was varied in order to determine the head position that elicited the maximal and minimal responses for each afferent. The response gain and phase values obtained to 0.5-Hz and 2-Hz linear acceleration stimuli were then plotted as a function of head orientation and a modified cosine function was fit to the data. From the best-fit cosine function, the predicted head orientations that would produce the maximal and minimal response gains were estimated. The estimated maximum response gains to linear acceleration in the utricular plane for the afferents varied between 75 and 1420 spikes s-1 g-1. The mean maximal gains for all afferents to 0.5-Hz and 2-Hz sinusoidal linear acceleration stimuli were 282 and 367 spikes s-1 g-1, respectively. The minimal response gains were essentially zero for most units. The response phases always led linear acceleration and remained constant for each afferent, regardless of head orientation. These response characteristics indicate that otolith afferents are cosine tuned and behave as one-dimensional linear accelerometers. The directions of maximal sensitivity to linear acceleration for the afferents varied throughout the plane of the utricle; however, most vectors were directed out of the opposite ear near the interaural axis. The response dynamics of the afferents were tested using stimulus frequencies ranging between 0.25 Hz and 10 Hz (0.1 g peak acceleration). Across stimulus frequencies, most afferents had increasing gains and constant phase values. These dynamic properties for individual afferents were fit with a simple transfer function that included three parameters: a mechanical time constant, a gain constant, and a fractional order distributed adaptation operator.

  11. Air-cushion lift pad

    NASA Technical Reports Server (NTRS)

    Blaise, H. T.; Dane, D. H.

    1969-01-01

    Mathematical model is formulated for an air pad which is capable of lifting a structure to a height of 0.125 inch. Design is superior to conventional air cushion devices because it eliminates flutter, vibration, heaving, and pitching.

  12. Teaching with iPads

    NASA Astrophysics Data System (ADS)

    Maj, Hubert

    2015-04-01

    Bilingual students in high school with bilingual units in Boguchwała have received iPads for learning English and a few subjects using CLIL (biology, basics of entrepreneurship, geography, IT and mathematics). Lessons with iPads are interesting for students for several reasons. First of all, teenagers like new technologies and using iPads for teaching helps students to learn by fun. Secondly, iPads give new possibilities of looking for knowledge about each theme. Moreover, teaching with iPads develops students' engagement. They have a chance to choose a few among over 65 000 applications for gathering and then presenting information about the lesson topic. They can easily prepare presentations, movies, cartoons, mind maps or whatever they like. Teaching students, thanks to the iPads, makes it their initiative, and the teacher can inspire them to look for the knowledge rather than disciplining pupils. But teaching with iPads is connected with many problems. For instance, there are not any examples on how to teach using these tools. It is very up-to-date technology and teachers firstly must learn the possibilities of iPads and look for new applications. It takes much time, especially at the beginning, and is difficult especially for inexperienced teachers. In addition, it is almost impossible to maintain control of the iPads for all of the students during the lesson. They can use their iPads for something unconnected with the topic of the lesson. Thirdly is lack of time - active methods (with iPads as well) are more time-consuming and it could be that they do not finish the whole program. And of course the last, but not at least, is the problem of money. Some of the applications must be paid for, and it is usually obligatory to possess a credit card. Fortunately, it is not expensive - applications usually cost a few euros and many of them are free and really good.

  13. Effect of Microgravity on Afferent Innervation

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Presentations and publications are: (1) an audiovisual summary web presentation on results from SLM-MIR avian experiments. A color presentation summarizing results from the SLM-MIR and STS-29 avian experiments; (2) color threshold and ratio of S 100B MAP5, NF68/200, GABA and GAD; (3) chicken (Gallus domesticus) inner ear afferents; (4) microgravity in the STS-29 Space Shuttle Discovery affected the vestibular system of chick embryos; (5) expression of S 100B in sensory and secretory cells of the vertebrate inner ear; (6) otoconia biogenesis, phylogeny, composition and functional attributes;(7) the glycan keratin sulfate in inner ear crystals; (8) elliptical-P cells in the avian perilymphatic interface of the tegmentum vasculosum; and (9) LAMP2c and S100B upregulation in brain stem after VIIIth nerve deafferentation.

  14. Chicken (Gallus domesticus) inner ear afferents

    NASA Technical Reports Server (NTRS)

    Hara, H.; Chen, X.; Hartsfield, J. F.; Hara, J.; Martin, D.; Fermin, C. D.

    1998-01-01

    Neurons from the vestibular (VG) and the statoacoustic (SAG) ganglion of the chick (Gallus domesticus) were evaluated histologically and morphometrically. Embryos at stages 34 (E8 days), 39 (E13 days) and 44 (E18 days) were sacrificed and temporal bones microdissected. Specimens were embedded in JB-4 methacrylate plastic, and stained with a mixture of 0.2% toluidine blue (TB) and 0.1% basic Fuschin in 25% ethanol or with a mixture of 2% TB and 1% paraphenylenediamine (PDA) for axon and myelin measurement study. Images of the VIIIth nerve were produced by a V150 (R) color imaging system and the contour of 200-300 neuronal bodies (perikarya) was traced directly on a video screen with a mouse in real time. The cross-sectional area of VG perikarya was 67.29 micrometers2 at stage 34 (E8), 128.46 micrometers2 at stage 39 (E13) and 275.85 micrometers2 at stage 44 (E18). The cross-sectional area of SAG perikarya was 62.44 micrometers2 at stage 34 (E8), 102.05 micrometers2 at stage 39 (E13) and 165.02 micrometers2 at stage 44 (E18). A significant cross-sectional area increase of the VG perikarya between stage 39 (E13) and stage 44 (E18) was determined. We randomly measured the cross-sectional area of myelin and axoplasm of hatchling afferent nerves, and found a correspondence between axoplasmic and myelin cross-sectional area in the utricular, saccular and semicircular canal nerve branches of the nerve. The results suggest that the period between stage 34 (E8) and 39 (E13) is a critical period for afferent neuronal development. Physiological and behavioral vestibular properties of developing and maturing hatchlings may change accordingly. The results compliment previous work by other investigators and provide valuable anatomical measures useful to correlate physiological data obtained from stimulation of the whole nerve or its parts.

  15. Circadian variation in gastric vagal afferent mechanosensitivity.

    PubMed

    Kentish, Stephen J; Frisby, Claudine L; Kennaway, David J; Wittert, Gary A; Page, Amanda J

    2013-12-01

    Food intake is coordinated to cellular metabolism by clock gene expression with a master clock in the suprachiasmatic nucleus synchronized by light exposure. Gastric vagal afferents play a role in regulating food intake, but it is unknown whether they exhibit circadian variation in their mechanosensitivity. We aimed to determine whether gastric vagal afferents express clock genes and whether their response to mechanical stimuli oscillates throughout the light/dark cycle. Nodose ganglia were collected from 8-week-old female C57BL/6 mice every 3 h starting at lights off (1800 h) to quantify Bmal1, Per1, Per2, and Nr1d1 mRNA by qRT-PCR. Additionally in vitro single-fiber recordings of gastric vagal mechanoreceptors were taken at all time points. Per1, Per2, Bmal1, and Nr1d1 mRNA is expressed in the nodose ganglia and levels oscillated over a 24 h period. In mice fed ad libitum, gastric content was 3 times higher at 0000 h and 0300 h than 1200 h. The response of tension receptors to 3 g stretch was reduced by up to 70% at 2100 h, 0000 h, and 0300 h compared with 1200 h. Gastric mucosal receptor response to stroking with a 50 mg von Frey hair was 3 times greater at 1200 h and 1500 h than the response at 0000 h. Similar findings were obtained in mice fasted for 6 h or maintained in darkness for 3 d before study. Therefore, these changes do not result from food intake or the light/dark cycle. Thus, gastric vagal mechanoreceptors display circadian rhythm, which may act to control food intake differentially at different times of the day. PMID:24305819

  16. Fluorescence depolarization measurements on oriented membranes.

    PubMed Central

    Adler, M; Tritton, T R

    1988-01-01

    We describe the theory and experimental application of fluorescence depolarization measurements on small molecules bound to oriented phospholipid bilayers. The results yield insight into both the orientation and the rotational motion of fluorophores in a membrane environment. To accomplish this the angular distribution of polarized fluorescence intensities is measured on a membrane preparation consisting of stacked phospholipid bilayers oriented in a known coordinate system. Considerably more information is available from this data than in comparable solution phase measurements. Three parameters are derived from the data: the rate of rotational diffusion and the second and fourth degree order parameters. These latter two parameters provide an assessment of the average distribution of fluorophore orientation in the membrane bilayer. The data have been carefully examined for systematic experimental artifacts and new protocols are presented which help to eliminate errors that have not been amply treated in the past. We present data for two types of fluorescent molecules: (a) conventional membrane probes like diphenylhexatriene, perylene and anthroyloxy fatty acids; and (b) the anticancer agent adriamycin and several congeneric anthracycline antibiotics. The results show that the hydrocarbon core of membranes is more rigid than previously thought, particularly above the thermal phase transition temperature. We also show that the orientation of small molecules is sensitive to both the phospholipid composition and to the interaction of specific functional groups with the lipid bilayer. The results are discussed in terms of energetic models describing the general patterns for the binding of small molecules to biological membranes. Images FIGURE 1 PMID:3165033

  17. Unmyelinated type II afferent neurons report cochlear damage

    PubMed Central

    Liu, Chang; Glowatzki, Elisabeth; Fuchs, Paul Albert

    2015-01-01

    In the mammalian cochlea, acoustic information is carried to the brain by the predominant (95%) large-diameter, myelinated type I afferents, each of which is postsynaptic to a single inner hair cell. The remaining thin, unmyelinated type II afferents extend hundreds of microns along the cochlear duct to contact many outer hair cells. Despite this extensive arbor, type II afferents are weakly activated by outer hair cell transmitter release and are insensitive to sound. Intriguingly, type II afferents remain intact in damaged regions of the cochlea. Here, we show that type II afferents are activated when outer hair cells are damaged. This response depends on both ionotropic (P2X) and metabotropic (P2Y) purinergic receptors, binding ATP released from nearby supporting cells in response to hair cell damage. Selective activation of P2Y receptors increased type II afferent excitability by the closure of KCNQ-type potassium channels, a potential mechanism for the painful hypersensitivity (that we term “noxacusis” to distinguish from hyperacusis without pain) that can accompany hearing loss. Exposure to the KCNQ channel activator retigabine suppressed the type II fiber’s response to hair cell damage. Type II afferents may be the cochlea’s nociceptors, prompting avoidance of further damage to the irreparable inner ear. PMID:26553995

  18. Identification and properties of parietal pleural afferents in rabbits

    PubMed Central

    Jammes, Yves; Trousse, Delphine; Delpierre, Stéphane

    2005-01-01

    Although pain and dyspnoea are common symptoms in pleural diseases, there are few studies on the sensory innervation of the pleura. Using rabbits, after removal of all muscles in the intercostal space to be studied, we investigated the afferents of the internal intercostal nerve by applying to the internal thoracic wall pieces of gauze soaked in warmed (37°C), buffered saline (mechanical stimulation) or solutions containing lactic acid, inflammatory mediators or capsaicin (chemical stimulation). The afferent conduction velocity ranged from 0.5 to 14 m s−1. Most units (97%) were activated by mechanical stimulation of the pleura (local positive pressure range = 4.5–8.5 cmH2O) and we found a linear relationship between the discharge rate of afferents and the force applied to the thoracic wall. The majority of mechanosensitive units (70%) also responded to one or several chemical agents. Thus, the afferents were activated by lactic acid (49%) and/or a mixture of inflammatory mediators (50%). Local application of capsaicin elicited an initial increased or decreased background afferent activity in 57% of the afferents, a delayed decrease in firing rate being noted in some units initially activated by capsaicin. Capsaicin blocked the afferent response to a further application of inflammatory mediators but did not affect the mechanosensitive units. Thus, sensory endings connected with thin myelinated and unmyelinated fibres in the internal intercostal nerve detect the mechanical and chemical events of pleural diseases. PMID:15975985

  19. Realizing controllable depolarization in photonic quantum-information channels

    SciTech Connect

    Shaham, A.; Eisenberg, H. S.

    2011-02-15

    Controlling the depolarization of light is a long-standing open problem. In recent years, many demonstrations have used the polarization of single photons to encode quantum information. The depolarization of these photons is equivalent to the decoherence of the quantum information they encode. We present schemes for building various depolarizing channels with controlled properties using birefringent crystals. Three such schemes are demonstrated, and their effects on single photons are shown by quantum process tomography to be in good agreement with a theoretical model.

  20. Depolarization artifacts in dual rotating-compensator Mueller matrix ellipsometry

    NASA Astrophysics Data System (ADS)

    Li, Weiqi; Zhang, Chuanwei; Jiang, Hao; Chen, Xiuguo; Liu, Shiyuan

    2016-05-01

    Noticeable depolarization effects are observed in the measurement of the air using an in-house developed dual rotating-compensator Mueller matrix ellipsometer. We demonstrate that these depolarization effects are essentially artifacts and mainly induced when the compensator with wavelength-dependent optical properties is integrated with the finite bandwidth detector. We define a general formula to represent the actual Mueller matrix of the compensator by taking into account the depolarization artifacts. After incorporating this formula into the system model, a correction method is further proposed, and consequently, improved accuracy can be achieved in the Mueller matrix measurement.

  1. Spreading convulsions, spreading depolarization and epileptogenesis in human cerebral cortex.

    PubMed

    Dreier, Jens P; Major, Sebastian; Pannek, Heinz-Wolfgang; Woitzik, Johannes; Scheel, Michael; Wiesenthal, Dirk; Martus, Peter; Winkler, Maren K L; Hartings, Jed A; Fabricius, Martin; Speckmann, Erwin-Josef; Gorji, Ali

    2012-01-01

    Spreading depolarization of cells in cerebral grey matter is characterized by massive ion translocation, neuronal swelling and large changes in direct current-coupled voltage recording. The near-complete sustained depolarization above the inactivation threshold for action potential generating channels initiates spreading depression of brain activity. In contrast, epileptic seizures show modest ion translocation and sustained depolarization below the inactivation threshold for action potential generating channels. Such modest sustained depolarization allows synchronous, highly frequent neuronal firing; ictal epileptic field potentials being its electrocorticographic and epileptic seizure its clinical correlate. Nevertheless, Leão in 1944 and Van Harreveld and Stamm in 1953 described in animals that silencing of brain activity induced by spreading depolarization changed during minimal electrical stimulations. Eventually, epileptic field potentials were recorded during the period that had originally seen spreading depression of activity. Such spreading convulsions are characterized by epileptic field potentials on the final shoulder of the large slow potential change of spreading depolarization. We here report on such spreading convulsions in monopolar subdural recordings in 2 of 25 consecutive aneurismal subarachnoid haemorrhage patients in vivo and neocortical slices from 12 patients with intractable temporal lobe epilepsy in vitro. The in vitro results suggest that γ-aminobutyric acid-mediated inhibition protects from spreading convulsions. Moreover, we describe arterial pulse artefacts mimicking epileptic field potentials in three patients with subarachnoid haemorrhage that ride on the slow potential peak. Twenty-one of the 25 subarachnoid haemorrhage patients (84%) had 656 spreading depolarizations in contrast to only three patients (12%) with 55 ictal epileptic events isolated from spreading depolarizations. Spreading depolarization frequency and depression

  2. Vagal Afferent Innervation of the Airways in Health and Disease.

    PubMed

    Mazzone, Stuart B; Undem, Bradley J

    2016-07-01

    Vagal sensory neurons constitute the major afferent supply to the airways and lungs. Subsets of afferents are defined by their embryological origin, molecular profile, neurochemistry, functionality, and anatomical organization, and collectively these nerves are essential for the regulation of respiratory physiology and pulmonary defense through local responses and centrally mediated neural pathways. Mechanical and chemical activation of airway afferents depends on a myriad of ionic and receptor-mediated signaling, much of which has yet to be fully explored. Alterations in the sensitivity and neurochemical phenotype of vagal afferent nerves and/or the neural pathways that they innervate occur in a wide variety of pulmonary diseases, and as such, understanding the mechanisms of vagal sensory function and dysfunction may reveal novel therapeutic targets. In this comprehensive review we discuss historical and state-of-the-art concepts in airway sensory neurobiology and explore mechanisms underlying how vagal sensory pathways become dysfunctional in pathological conditions. PMID:27279650

  3. Depolarizing collisions with hydrogen: Neutral and singly ionized alkaline earths

    SciTech Connect

    Manso Sainz, Rafael; Ramos, Andrés Asensio; Bueno, Javier Trujillo; Aguado, Alfredo

    2014-06-20

    Depolarizing collisions are elastic or quasielastic collisions that equalize the populations and destroy the coherence between the magnetic sublevels of atomic levels. In astrophysical plasmas, the main depolarizing collider is neutral hydrogen. We consider depolarizing rates on the lowest levels of neutral and singly ionized alkali earths Mg I, Sr I, Ba I, Mg II, Ca II, and Ba II, due to collisions with H°. We compute ab initio potential curves of the atom-H° system and solve the quantum mechanical dynamics. From the scattering amplitudes, we calculate the depolarizing rates for Maxwellian distributions of colliders at temperatures T ≤ 10,000 K. A comparative analysis of our results and previous calculations in the literature is completed. We discuss the effect of these rates on the formation of scattering polarization patterns of resonant lines of alkali earths in the solar atmosphere, and their effect on Hanle effect diagnostics of solar magnetic fields.

  4. Air Bearing Lift Pad (ABLP)

    NASA Technical Reports Server (NTRS)

    Dane, Dan H.; Blaise, Herman T.

    1968-01-01

    Typical air bearings float on air films of only a few thousandths of an inch and so will only operate above very smooth, even surfaces. For the mechanical simulation of space, the small drag of the bladder type air pads is much more than can be coped with, and the practicality of large floor areas being machined for precision air bearings is nonexistent. To enable operation above surfaces that undulate slightly or feature cracks and discontinuities, an ABLP has been developed. It consists of a rigid pad beneath which an inflatable bladder is mounted. The bladder is inflated with air which then escapes through passages into a cavity in the center of the bladder to produce the lifting energy. As the air escapes about the perimeter of the bladder, a certain degree of balance and equilibrium is imparted to the pad as it is able to move a limited weight across slightly uneven surfaces.

  5. Differential central projections of vestibular afferents in pigeons

    NASA Technical Reports Server (NTRS)

    Dickman, J. D.; Fang, Q.

    1996-01-01

    The question of whether a differential distribution of vestibular afferent information to central nuclear neurons is present in pigeons was studied using neural tracer compounds. Discrete tracing of afferent fibers innervating the individual semicircular canal and otolith organs was produced by sectioning individual branches of the vestibular nerve that innervate the different receptor organs and applying crystals of horseradish peroxidase, or a horseradish peroxidase/cholera toxin mixture, or a biocytin compound for neuronal uptake and transport. Afferent fibers and their terminal distributions within the brainstem and cerebellum were visualized subsequently. Discrete areas in the pigeon central nervous system that receive primary vestibular input include the superior, dorsal lateral, ventral lateral, medial, descending, and tangential vestibular nuclei; the A and B groups; the intermediate, medial, and lateral cerebellar nuclei; and the nodulus, the uvula, and the paraflocculus. Generally, the vertical canal afferents projected heavily to medial regions in the superior and descending vestibular nuclei as well as the A group. Vertical canal projections to the medial and lateral vestibular nuclei were observed but were less prominent. Horizontal canal projections to the superior and descending vestibular nuclei were much more centrally located than those of the vertical canals. A more substantial projection to the medial and lateral vestibular nuclei was seen with horizontal canal afferents compared to vertical canal fibers. Afferents innervating the utricle and saccule terminated generally in the lateral regions of all vestibular nuclei in areas that were separate from the projections of the semicircular canals. In addition, utricular fibers projected to regions in the vestibular nuclei that overlapped with the horizontal semicircular canal terminal fields, whereas saccular afferents projected to regions that received vertical canal fiber terminations. Lagenar

  6. A deterministic method for studying depolarization in turbid media

    NASA Astrophysics Data System (ADS)

    Clark, Julia P.

    2016-05-01

    There are a number of interesting experimental and Monte Carlo results regarding the persistence of polarization in turbid media; however, there is not a good theoretical understanding of this phenomenon. These results include circular polarization memory in strongly scattering anisotropic media and the impact of polydisperse scatterers on the depolarization rate. In this work we use the spectrum of the discretized vector radiative transport equation to investigate to study circular depolarization in strongly scattering media.

  7. Depolarization effects in the active remote sensing of random media

    NASA Technical Reports Server (NTRS)

    Zuniga, M.; Kong, J. A.; Tsang, L.

    1980-01-01

    Backscattering cross sections for depolarization are derived for the active remote sensing of a two-layer random medium. It is shown that the depolarization effects arise as a second-order term in albedo under the Born approximation. The results of the backscattering cross sections are illustrated as functions of frequency and incident angles and used to match experimental data collected from a vegetation field.

  8. Acid-sensing by airway afferent nerves

    PubMed Central

    Lee, Lu-Yuan; Gu, Qihai; Xu, Fadi; Hong, Ju-Lun

    2013-01-01

    Inhalation of acid aerosol or aspiration of acid solution evokes a stimulatory effect on airway C-fiber and Aδ afferents, which in turn causes airway irritation and triggers an array of defense reflex responses (e.g., cough, reflex bronchoconstriction, etc.). Tissue acidosis can also occur locally in the respiratory tract as a result of ischemia or inflammation, such as in the airways of asthmatic patients during exacerbation. The action of proton on the airway sensory neurons is generated by activation of two different current species: a transient (rapidly activating and inactivating) current mediated through the acid-sensing ion channels, and a slowly activating and sustained current mediated through the transient receptor potential vanilloid type 1 (TRPV1) receptor. In view of the recent findings that the expression and/or sensitivity of TRPV1 are up-regulated in the airway sensory nerves during chronic inflammatory reaction, the proton-evoked irritant effects on these nerves may play an important part in the manifestation of various symptoms associated with airway inflammatory diseases. PMID:23524016

  9. Studies of Vehicular Padding Materials

    PubMed Central

    Sances, Anthony; Carlin, Fred H.; Herbst, Brian; Forrest, Steve; Meyer, Steve; Khadilkar, Anil; Friedman, Keith; Bish, Jack

    2000-01-01

    The Federal Motor Vehicle Safety Standard 571.201 discusses occupant protection with interior impacts of vehicles. Rule making by the National Highway Traffic Safety Administration (NHTSA) has identified padding for potential injury reduction in vehicles. In these studies, head injury mitigation with padding on vehicular roll bars and brush bars was evaluated. Studies were conducted with free falling Hybrid 50% male head form drops on the fore head and side of the head and a 5% female head. Marked reductions in angular acceleration, as well as Head Injury Criterions (HIC), were observed when compared to unpadded roll bars and brush bars. PMID:11558079

  10. Preliminary characterization of voltage-activated whole-cell currents in developing human vestibular hair cells and calyx afferent terminals.

    PubMed

    Lim, Rebecca; Drury, Hannah R; Camp, Aaron J; Tadros, Melissa A; Callister, Robert J; Brichta, Alan M

    2014-10-01

    We present preliminary functional data from human vestibular hair cells and primary afferent calyx terminals during fetal development. Whole-cell recordings were obtained from hair cells or calyx terminals in semi-intact cristae prepared from human fetuses aged between 11 and 18 weeks gestation (WG). During early fetal development (11-14 WG), hair cells expressed whole-cell conductances that were qualitatively similar but quantitatively smaller than those observed previously in mature rodent type II hair cells. As development progressed (15-18 WG), peak outward conductances increased in putative type II hair cells but did not reach amplitudes observed in adult human hair cells. Type I hair cells express a specific low-voltage activating conductance, G K,L. A similar current was first observed at 15 WG but remained relatively small, even at 18 WG. The presence of a "collapsing" tail current indicates a maturing type I hair cell phenotype and suggests the presence of a surrounding calyx afferent terminal. We were also able to record from calyx afferent terminals in 15-18 WG cristae. In voltage clamp, these terminals exhibited fast inactivating inward as well as slower outward conductances, and in current clamp, discharged a single action potential during depolarizing steps. Together, these data suggest the major functional characteristics of type I and type II hair cells and calyx terminals are present by 18 WG. Our study also describes a new preparation for the functional investigation of key events that occur during maturation of human vestibular organs. PMID:24942706

  11. Afferent innervation of the utricular macula in pigeons

    NASA Technical Reports Server (NTRS)

    Si, Xiaohong; Zakir, Mridha Md; Dickman, J. David

    2003-01-01

    Biotinylated dextran amine (BDA) was used to retrogradely label afferents innervating the utricular macula in adult pigeons. The pigeon utriclar macula consists of a large rectangular-shaped neuroepithelium with a dorsally curved anterior edge and an extended medioposterior tail. The macula could be demarcated into several regions based on cytoarchitectural differences. The striola occupied 30% of the macula and contained a large density of type I hair cells with fewer type II hair cells. Medial and lateral extrastriola zones were located outside the striola and contained only type II hair cells. A six- to eight-cell-wide band of type II hair cells existed near the center of the striola. The reversal line marked by the morphological polarization of hair cells coursed throughout the epithelium, near the peripheral margin, and through the center of the type II band. Calyx afferents innervated type I hair cells with calyceal terminals that contained between 2 and 15 receptor cells. Calyx afferents were located only in the striola region, exclusive of the type II band, had small total fiber innervation areas and low innervation densities. Dimorph afferents innervated both type I and type II hair cells with calyceal and bouton terminals and were primarily located in the striola region. Dimorph afferents had smaller calyceal terminals with few type I hair cells, extended fiber branches with bouton terminals and larger innervation areas. Bouton afferents innervated only type II hair cells in the extrastriola and type II band regions. Bouton afferents innervating the type II band had smaller terminal fields with fewer bouton terminals and smaller innervation areas than fibers located in the extrastriolar zones. Bouton afferents had the most bouton terminals on the longest fibers, the largest innervation areas with the highest innervation densities of all afferents. Among all afferents, smaller terminal innervation fields were observed in the striola and large fields were

  12. Hump behind the shoulders (Dorsocervical fat pad)

    MedlinePlus

    Buffalo hump; Dorsocervical fat pad ... Cause of dorsocervical fat pad includes any of the following: Certain medicines used to treat HIV or AIDS Long-term use of certain glucocorticoid medicines, ...

  13. Your P.A.D. Checklist

    MedlinePlus

    ... on. Feature: Peripheral Artery Disease Your P.A.D. Checklist Past Issues / Fall 2011 Table of Contents ... your risk of peripheral artery disease (P.A.D.). That can start by making sure you “know ...

  14. Your P.A.D. Checklist

    MedlinePlus

    ... Home Current Issue Past Issues Special Section Your P.A.D. Checklist Past Issues / Summer 2008 Table ... and reduce your risk of peripheral arterial disease (P.A.D.). That can start by making sure ...

  15. Your P.A.D. Checklist

    MedlinePlus

    ... Issue Past Issues Special Section Your P.A.D. Checklist Past Issues / Summer 2008 Table of Contents ... your risk of peripheral arterial disease (P.A.D.). That can start by making sure you "know ...

  16. Laboratory investigations of mineral dust near-backscattering depolarization ratios

    NASA Astrophysics Data System (ADS)

    Järvinen, E.; Kemppinen, O.; Nousiainen, T.; Kociok, T.; Möhler, O.; Leisner, T.; Schnaiter, M.

    2016-07-01

    Recently, there has been increasing interest to derive the fractions of fine- and coarse-mode dust particles from polarization lidar measurements. For this, assumptions of the backscattering properties of the complex dust particles have to be made either by using empirical data or particle models. Laboratory measurements of dust backscattering properties are important to validate the assumptions made in the lidar retrievals and to estimate their uncertainties. Here, we present laboratory measurements of linear and circular near-backscattering (178°) depolarization ratios of over 200 dust samples measured at 488 and 552 nm wavelengths. The measured linear depolarization ratios ranged from 0.03 to 0.36 and were strongly dependent on the particle size. The strongest size-dependence was observed for fine-mode particles as their depolarization ratios increased almost linearly with particle median diameter from 0.03 to 0.3, whereas the coarse-mode particle depolarization values stayed rather constant with a mean linear depolarization ratio of 0.27. The depolarization ratios were found to be insensitive to the dust source region or thin coating of the particles or to changes in relative humidity. We compared the measurements with results of three different scattering models. With certain assumptions for model particle shape, all the models were capable of correctly describing the size-dependence of the measured dust particle, albeit the model particles significantly differed in composition, shape and degree of complexity. Our results show potential for distinguishing the dust fine- and coarse-mode distributions based on their depolarization properties and, thus, can serve the lidar community as an empirical reference.

  17. An ionic current model for neurons in the rat medial nucleus tractus solitarii receiving sensory afferent input.

    PubMed Central

    Schild, J H; Khushalani, S; Clark, J W; Andresen, M C; Kunze, D L; Yang, M

    1993-01-01

    1. Neurons from a horizontal slice of adult rat brainstem were examined using intracellular recording techniques. Investigations were restricted to a region within the nucleus tractus solitarii, medial to the solitary tract and centred on the obex (mNTS). Previous work has shown this restricted area of the NTS to contain the greatest concentration of aortic afferent baroreceptor terminal fields. Electrical stimulation of the tract elicited short-latency excitatory postsynaptic potentials in all neurons. 2. mNTS neurons were spontaneously active with firing frequencies ranging between 1 and 10 Hz, at resting potentials of -65 to -45 mV. These neurons did not exhibit spontaneous bursting activity. 3. Depolarizing current injection immediately evoked a finite, high-frequency spike discharge which rapidly declined to a lower steady-state level (i.e. spike frequency adaptation, SFA). Increasing depolarizations produced a marked increase in the peak instantaneous frequency but a much smaller increase in the steady-state firing level. 4. Conditioning with a hyperpolarizing prepulse resulted in a prolonged delay of up to 600 ms before the first action potential (i.e. delayed excitation, DE) with an attendant decrease in peak discharge rates. DE was modulated by both the magnitude and duration of the prestimulus hyperpolarization, as well as the magnitude of the depolarizing stimulus. Tetrodotoxin (TTX) eliminated spike discharge but had little effect on the ramp-like membrane depolarization characteristic of DE. 5. We have developed a mathematical model for mNTS neurons to facilitate our understanding of the interplay between the underlying ionic currents. It consists of a comprehensive membrane model of the Hodgkin-Huxley type coupled with a fluid compartment model describing cytoplasmic [Ca2+]i homeostasis. 6. The model suggests that (a) SFA is caused by an increase in [Ca2+]i which activates the outward K+ current, IK,Ca, and (b) DE results from the competitive

  18. 21 CFR 878.4440 - Eye pad.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Eye pad. 878.4440 Section 878.4440 Food and Drugs... GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4440 Eye pad. (a) Identification. An eye pad is... use as a bandage over the eye for protection or absorption of secretions. (b) Classification. Class...

  19. 21 CFR 878.4440 - Eye pad.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Eye pad. 878.4440 Section 878.4440 Food and Drugs... GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4440 Eye pad. (a) Identification. An eye pad is... use as a bandage over the eye for protection or absorption of secretions. (b) Classification. Class...

  20. Peripheral Arterial Disease (P.A.D.)

    MedlinePlus

    ... turn Javascript on. Peripheral Artery Disease (P.A.D.) What is P.A.D.? Arteries Clogged With Plaque Peripheral arterial disease (P. ... button on your keyboard.) Why Is P.A.D. Dangerous? Click for more information Blocked blood flow ...

  1. 21 CFR 878.4440 - Eye pad.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Eye pad. 878.4440 Section 878.4440 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4440 Eye pad. (a) Identification. An eye pad...

  2. 21 CFR 878.4440 - Eye pad.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Eye pad. 878.4440 Section 878.4440 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4440 Eye pad. (a) Identification. An eye pad...

  3. 21 CFR 878.4440 - Eye pad.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Eye pad. 878.4440 Section 878.4440 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4440 Eye pad. (a) Identification. An eye pad...

  4. Modulation of the hyperpolarization-activated current (Ih) by cyclic nucleotides in guinea-pig primary afferent neurons.

    PubMed Central

    Ingram, S L; Williams, J T

    1996-01-01

    1. Whole-cell patch-clamp recordings were made from dissociated guinea-pig nodose and trigeminal ganglion neurons in culture to study second messenger mechanisms of the hyperpolarization-activated current (Ih) modulation. 2. Prostaglandin E2 (PGE2) and forskolin modulate Ih in primary afferents by shifting the activation curve in the depolarizing direction and increasing the maximum amplitude. 3. The cAMP analogues, RP-cAMP-S (an inhibitor of protein kinase A (PKA)) and SP-cAMP-S (an activator of PKA), both shifted the activation curve of Ih to more depolarized potentials and occluded the effects of forskolin. These results suggest that Ih is modulated by a direct action of the cAMP analogues. 4. Superfusion of other cyclic nucleotide analogues (8-Br-cAMP, 8-(4-chlorophenylthio)-cAMP and 8-Br-cGMP) mimicked the actions of forskolin and PGE2, but dibutyryl cGMP, 5'-AMP and adenosine had no effect on Ih. 8-Br-cAMP and 8-Br-cGMP had similar concentration response profiles, suggesting that Ih has little nucleotide selectivity. 5. The inhibitor peptide (PKI), the catalytic subunit of PKA (C subunit) and phosphatase inhibitors (microcystin and okadaic acid) had no effect on forskolin modulation of Ih. 6. These results indicate that Ih is regulated by cyclic nucleotides in sensory neurons. Positive regulation of Ih by prostaglandins produced during inflammation may lead to depolarization and facilitation of repetitive activity, and thus contribute to sensitization to painful stimuli. PMID:8730586

  5. Nanomolar oxytocin synergizes with weak electrical afferent stimulation to activate the locomotor CpG of the rat spinal cord in vitro.

    PubMed

    Dose, Francesco; Zanon, Patrizia; Coslovich, Tamara; Taccola, Giuliano

    2014-01-01

    Synergizing the effect of afferent fibre stimulation with pharmacological interventions is a desirable goal to trigger spinal locomotor activity, especially after injury. Thus, to better understand the mechanisms to optimize this process, we studied the role of the neuropeptide oxytocin (previously shown to stimulate locomotor networks) on network and motoneuron properties using the isolated neonatal rat spinal cord. On motoneurons oxytocin (1 nM-1 μM) generated sporadic bursts with superimposed firing and dose-dependent depolarization. No desensitization was observed despite repeated applications. Tetrodotoxin completely blocked the effects of oxytocin, demonstrating the network origin of the responses. Recording motoneuron pool activity from lumbar ventral roots showed oxytocin mediated depolarization with synchronous bursts, and depression of reflex responses in a stimulus and peptide-concentration dependent fashion. Disinhibited bursting caused by strychnine and bicuculline was accelerated by oxytocin whose action was blocked by the oxytocin antagonist atosiban. Fictive locomotion appeared when subthreshold concentrations of NMDA plus 5HT were coapplied with oxytocin, an effect prevented after 24 h incubation with the inhibitor of 5HT synthesis, PCPA. When fictive locomotion was fully manifested, oxytocin did not change periodicity, although cycle amplitude became smaller. A novel protocol of electrical stimulation based on noisy waveforms and applied to one dorsal root evoked stereotypic fictive locomotion. Whenever the stimulus intensity was subthreshold, low doses of oxytocin triggered fictive locomotion although oxytocin per se did not affect primary afferent depolarization evoked by dorsal root pulses. Among the several functional targets for the action of oxytocin at lumbar spinal cord level, the present results highlight how small concentrations of this peptide could bring spinal networks to threshold for fictive locomotion in combination with other

  6. Effect of multiple scattering on depolarization measurements with spaceborne lidars.

    PubMed

    Reichardt, Susanne; Reichardt, Jens

    2003-06-20

    An analytical model based on the integration of the scattering-angle and light-path manifold has been developed to quantify the effect of multiple scattering on cirrus measurements obtained with elastic polarization lidars from space. Light scattering by molecules and by a horizontally homogeneous cloud is taken into account. Lidar parameter, including laser beam divergence, can be freely chosen. Up to 3 orders of scattering are calculated. Furthermore, an inversion technique for the retrieval of cloud extinction profiles from measurements with elastic-backscatter lidars is proposed that explicitly takes multiple scattering into account. It is found that for typical lidar system parameters such as those of the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) instrument multiple scattering does not significantly affect depolarization-ratio measurements in cirrus clouds with small to moderate optical depths. For all simulated clouds, the absolute value of the difference between measured and single-scattering volume depolarization ratio is < 0.006. The particle depolarization ratio can be calculated from the measured volume depolarization ratio and the retrieved backscatter ratio without degradation of accuracy; thus characterization of the various cirrus categories in terms of the particle depolarization ratio and retrieval of cloud microphysical properties is feasible from space. The results of this study apply to polar stratospheric clouds as well. PMID:12833968

  7. In vitro Functional Characterization of Mouse Colorectal Afferent Endings

    PubMed Central

    Feng, Bin; Gebhart, G.F.

    2015-01-01

    This video demonstrates in detail an in vitro single-fiber electrophysiological recording protocol using a mouse colorectum-nerve preparation. The approach allows unbiased identification and functional characterization of individual colorectal afferents. Extracellular recordings of propagated action potentials (APs) that originate from one or a few afferent (i.e., single-fiber) receptive fields (RFs) in the colorectum are made from teased nerve fiber fascicles. The colorectum is removed with either the pelvic (PN) or lumbar splanchnic (LSN) nerve attached and opened longitudinally. The tissue is placed in a recording chamber, pinned flat and perfused with oxygenated Krebs solution. Focal electrical stimulation is used to locate the colorectal afferent endings, which are further tested by three distinct mechanical stimuli (blunt probing, mucosal stroking and circumferential stretch) to functionally categorize the afferents into five mechanosensitive classes. Endings responding to none of these mechanical stimuli are categorized as mechanically-insensitive afferents (MIAs). Both mechanosensitive and MIAs can be assessed for sensitization (i.e., enhanced response, reduced threshold, and/or acquisition of mechanosensitivity) by localized exposure of RFs to chemicals (e.g., inflammatory soup (IS), capsaicin, adenosine triphosphate (ATP)). We describe the equipment and colorectum–nerve recording preparation, harvest of colorectum with attached PN or LSN, identification of RFs in the colorectum, single-fiber recording from nerve fascicles, and localized application of chemicals to the RF. In addition, challenges of the preparation and application of standardized mechanical stimulation are also discussed. PMID:25651300

  8. Histaminergic afferent system in the cerebellum: structure and function.

    PubMed

    Li, Bin; Zhu, Jing-Ning; Wang, Jian-Jun

    2014-01-01

    Histaminergic afferent system of the cerebellum, having been considered as an essential component of the direct hypothalamocerebellar circuits, originates from the tuberomammillary nucleus in the hypothalamus. Unlike the mossy fibers and climbing fibers, the histaminergic afferent fibers, a third type of cerebellar afferents, extend fine varicose fibers throughout the cerebellar cortex and nuclei. Histamine receptors, belonging to the family of G protein-coupled receptors, are widely present in the cerebellum. Through these histamine receptors, histamine directly excites Purkinje cells and granule cells in the cerebellar cortex, as well as the cerebellar nuclear neurons. Therefore, the histaminergic afferents parallelly modulate these dominant components in the cerebellar circuitry and consequently influence the final output of the cerebellum. In this way, the histaminergic afferent system actively participates in the cerebellum-mediated motor balance and coordination and nonsomatic functions. Accordingly, histaminergic reagents may become potential drugs for clinical treatment of cerebellar ataxia and other cerebellar disease. On the other hand, considering the hypothalamus is a high regulatory center for autonomic and visceral activities, the hypothalamocerebellar histaminergic fibers/projections, bridging the nonsomatic center to somatic structure, may play a critical role in the somatic-nonsomatic integration. PMID:26331029

  9. Semicircular Canal Geometry, Afferent Sensitivity And Animal Behavior

    PubMed Central

    Hullar, Timothy A.

    2008-01-01

    The geometry of the semicircular canals has been used in evolutionary studies to predict the behaviors of extinct animals. These predictions have relied on an assumption that the responses of the canals can be determined from their dimensions, and that an organism’s behavior can be determined from these responses. However, the relationship between a canal’s sensitivity and its size is not well known. An intraspecies comparison among canal responses in each of three species (cat, squirrel monkey, and pigeon) was undertaken to evaluate various models of canal function and determine how their dimensions may be related to afferent physiology. All models predicted the responses of the cat afferents, but the models performed less well for squirrel monkey and pigeon. Possible causes for this discrepancy include incorrectly assuming that afferent responses accurately represent canal function, or errors in current biophysical models of the canals. These findings leave open the question as to how reliably canal anatomy can be used to estimate afferent responses and how closely afferent responses are related to behavior. Other labyrinthine features—such as orientation of the horizontal canal, which is reliably held near earth-horizontal across many species—may be better to use when extrapolating the posture and related behavior of extinct animals from labyrinthine morphology. PMID:16550591

  10. Acousto-optic deflector of depolarized laser radiation

    NASA Astrophysics Data System (ADS)

    Antonov, S. N.

    2016-01-01

    An original acousto-optic deflector is based on the anisotropic diffraction in the paratellurite crystal. The deflector is characterized by a relatively high diffraction efficiency for depolarized laser radiation. The deflector consists of two sequential acousto-optic cells. Each cell deflects one of the orthogonally polarized components of the originally depolarized radiation. The first and second cells scan the low- and highfrequency parts of the angular interval, respectively. The simultaneous and independent operation of the cells makes it possible to use the entire optical (laser) power. A frequency band of 32 MHz is almost reached for depolarized radiation with a wavelength of 1.06 µm and the absolute angular interval is 50 mrad at a total efficiency of no less than 70%.

  11. Depolarization of subalfvenic plasma jet generating field-aligned currents

    NASA Astrophysics Data System (ADS)

    Sobyanin, D. B.; Gavrilov, B. G.; Podgorny, I. M.

    2004-01-01

    The subalfvenic magnetized plasma jet propagating across the geomagnetic field generates the field-aligned currents in ionospheric plasma. The transverse polarization electric field Ep = - V × B in the jet is reduced due to a leakage of polarization charges through the field-aligned currents (plasma jet depolarization). These phenomena are investigated in the laboratory experiment. It was revealed that the depolarization is accompanied by appearing of the electric field Ea along the plasma velocity vector and creation of an additional pair of the field-aligned currents being generated at the leading and trailing edge of the moving plasma. The value of Ea is comparable with the transverse electric field Ep. The depolarization results in the plasma jet deflection. The possibility of a manifestation of these effects in the NORTH STAR Russian-American active rocket experiment is discussed.

  12. STS-120 on Launch Pad

    NASA Technical Reports Server (NTRS)

    2007-01-01

    A photographer used a fisheye lens attached to an electronic still camera to record a series of photos of the Space Shuttle Discovery at the launch pad while the STS-120 crew was at Kennedy Space Center for the Terminal Countdown Demonstration Test in October 2007. The STS-120 mission launched from Kennedy Space Center's launch pad 39A at 11:38:19 a.m. (EDT) on October 23, 2007. The crew included Scott E. Parazynski, Douglas H. Wheelock, Stephanie D. Wilson, all mission specialists; George D. Zamka, pilot; Pamela A. Melroy, commander; Daniel M. Tani, Expedition 16 flight engineer; and Paolo A. Nespoli, mission specialist representing the European Space Agency (ESA). Major objectives included the installation of the P6 solar array of the port truss and delivery and installment of Harmony, the Italian-built U.S. Node 2 on the International Space Station (ISS).

  13. Depolarizing GABA acts on intrinsically bursting pyramidal neurons to drive giant depolarizing potentials in the immature hippocampus.

    PubMed

    Sipilä, Sampsa T; Huttu, Kristiina; Soltesz, Ivan; Voipio, Juha; Kaila, Kai

    2005-06-01

    Spontaneous periodic network events are a characteristic feature of developing neuronal networks, and they are thought to play a crucial role in the maturation of neuronal circuits. In the immature hippocampus, these types of events are seen in intracellular recordings as giant depolarizing potentials (GDPs) during the stage of neuronal development when GABA(A)-mediated transmission is depolarizing. However, the precise mechanism how GABAergic transmission promotes GDP occurrence is not known. Using whole-cell, cell-attached, perforated-patch, and field-potential recordings in hippocampal slices, we demonstrate here that CA3 pyramidal neurons in the newborn rat generate intrinsic bursts when depolarized. Furthermore, the characteristic rhythmicity of GDP generation is not based on a temporally patterned output of the GABAergic interneuronal network. However, GABAergic depolarization plays a key role in promoting voltage-dependent, intrinsic pyramidal bursting activity. The present data indicate that glutamatergic CA3 neurons have an instructive, pacemaker role in the generation of GDPs, whereas both synaptic and tonic depolarizing GABAergic mechanisms exert a temporally nonpatterned, facilitatory action in the generation of these network events. PMID:15930375

  14. Dark-field circular depolarization optical coherence microscopy

    PubMed Central

    Mehta, Kalpesh; Zhang, Pengfei; Yeo, Eugenia Li Ling; Kah, James Chen Yong; Chen, Nanguang

    2013-01-01

    Optical coherence microscopy (OCM) is a widely used structural imaging modality. To extend its application in molecular imaging, gold nanorods are widely used as contrast agents for OCM. However, they very often offer limited sensitivity as a result of poor signal to background ratio. Here we experimentally demonstrate that a novel OCM implementation based on dark-field circular depolarization detection can efficiently detect circularly depolarized signal from gold nanorods and at the same time efficiently suppress the background signals. This results into a significant improvement in signal to background ratio. PMID:24049689

  15. Possible Depolarization Mechanism due to Low Beta Squeeze

    SciTech Connect

    Ranjbar,V.; Luccio, A.; Bai, M.

    2008-04-01

    Simulations reveal a potential depolarization mechanism during low beta squeeze. This depolarization appears to be driven by a spin tune modulation caused by spin precession through the strong low beta quads due to the vertical fields. The modulation of the spin tune introduces an additional snake resonance condition at {nu}{sub s0} {+-} n{nu}{sub x} - {nu}{sub z}l = integer which while the same numerology as the well known sextupole resonance, can operate in the absence of sextupole elements.

  16. Depolarization Alters Phenotype, Maintains Plasticity of Predifferentiated Mesenchymal Stem Cells

    PubMed Central

    Sundelacruz, Sarah; Levin, Michael

    2013-01-01

    Although adult stem cell transplantation has been implemented as a therapy for tissue repair, it is limited by the availability of functional adult stem cells. A potential approach to generate stem and progenitor cells may be to modulate the differentiated status of somatic cells. Therefore, there is a need for a better understanding of how the differentiated phenotype of mature cells is regulated. We hypothesize that bioelectric signaling plays an important role in the maintenance of the differentiated state, as it is a functional regulator of the differentiation process in various cells and tissues. In this study, we asked whether the mature phenotype of osteoblasts and adipocytes derived from human mesenchymal stem cells (hMSCs) could be altered by modulation of their membrane potential. hMSC-derived osteoblasts and adipocytes were depolarized by treatment with ouabain, a Na+/K+ ATPase inhibitor, or by treatment with high concentrations of extracellular K+. To characterize the effect of voltage modulation on the differentiated state, the depolarized cells were evaluated for (1) the loss of differentiation markers; (2) the up-regulation of stemness markers and stem properties; and (3) differences in gene expression profiles in response to voltage modulation. hMSC-derived osteoblasts and adipocytes exhibited significant down-regulation of bone and fat tissue markers in response to depolarization, despite the presence of differentiation-inducing soluble factors, suggesting that bioelectric signaling overrides biochemical signaling in the maintenance of cell state. Suppression of the osteoblast or adipocyte phenotype was not accompanied by up-regulation of genes associated with the stem state. Thus, depolarization does not activate the stem cell genetic signature and, therefore, does not induce a full reprogramming event. However, after transdifferentiating the depolarized cells to evaluate for multi-lineage potential, depolarized osteoblasts demonstrated improved

  17. Neutron depolarization study of phase transformations in steel

    NASA Astrophysics Data System (ADS)

    van Dijk, N. H.; Te Velthuis, S. G. E.; Rekveldt, M. Th.; Sietsma, J.; van der Zwaag, S.

    1999-06-01

    Three-dimensional neutron depolarization experiments have been performed in order to study the phase transformations from austenite (γ-Fe) into ferrite (α-Fe) and cementite (Fe 3C) in two medium-carbon steel samples with different carbon concentrations. The rotation of the neutron polarization vector during transmission through the sample is a direct measure for the ferromagnetic ferrite fraction. The degree of depolarization is related to the magnetic correlation length, which gives an indication of the characteristic length scales of the microstructure.

  18. Determinants of Spatial and Temporal Coding by Semicircular Canal Afferents

    PubMed Central

    Highstein, Stephen M.; Rabbitt, Richard D.; Holstein, Gay R.; Boyle, Richard D.

    2010-01-01

    The vestibular semicircular canals are internal sensors that signal the magnitude, direction, and temporal properties of angular head motion. Fluid mechanics within the 3-canal labyrinth code the direction of movement and integrate angular acceleration stimuli over time. Directional coding is accomplished by decomposition of complex angular accelerations into 3 biomechanical components—one component exciting each of the 3 ampullary organs and associated afferent nerve bundles separately. For low-frequency angular motion stimuli, fluid displacement within each canal is proportional to angular acceleration. At higher frequencies, above the lower corner frequency, real-time integration is accomplished by viscous forces arising from the movement of fluid within the slender lumen of each canal. This results in angular velocity sensitive fluid displacements. Reflecting this, a subset of afferent fibers indeed report angular acceleration to the brain for low frequencies of head movement and report angular velocity for higher frequencies. However, a substantial number of afferent fibers also report angular acceleration, or a signal between acceleration and velocity, even at frequencies where the endolymph displacement is known to follow angular head velocity. These non-velocity-sensitive afferent signals cannot be attributed to canal biomechanics alone. The responses of non-velocity-sensitive cells include a mathematical differentiation (first-order or fractional) imparted by hair-cell and/or afferent complexes. This mathematical differentiation from velocity to acceleration cannot be attributed to hair cell ionic currents, but occurs as a result of the dynamics of synaptic transmission between hair cells and their primary afferent fibers. The evidence for this conclusion is reviewed below. PMID:15845995

  19. A novel role for TRPM8 in visceral afferent function.

    PubMed

    Harrington, Andrea M; Hughes, Patrick A; Martin, Christopher M; Yang, Jing; Castro, Joel; Isaacs, Nicole J; Blackshaw, L Ashley; Brierley, Stuart M

    2011-07-01

    Transient receptor potential ion channel melastatin subtype 8 (TRPM8) is activated by cold temperatures and cooling agents, such as menthol and icilin. Compounds containing peppermint are reported to reduce symptoms of bowel hypersensitivity; however, the underlying mechanisms of action are unclear. Here we determined the role of TRPM8 in colonic sensory pathways. Laser capture microdissection, quantitative reverse transcription-polymerase chain reaction (RT-PCR), immunofluorescence, and retrograde tracing were used to localise TRPM8 to colonic primary afferent neurons. In vitro extracellular single-fibre afferent recordings were used to determine the effect of TRPM8 channel activation on the chemosensory and mechanosensory function of colonic high-threshold afferent fibres. TRPM8 mRNA was present in colonic DRG neurons, whereas TRPM8 protein was present on nerve fibres throughout the wall of the colon. A subpopulation (24%, n=58) of splanchnic serosal and mesenteric afferents tested responded directly to icilin (5 μmol/L). Subsequently, icilin significantly desensitised afferents to mechanical stimulation (P<.0001; n=37). Of the splanchnic afferents responding to icilin, 21 (33%) also responded directly to the TRPV1 agonist capsaicin (3 μmol/L), and icilin reduced the direct chemosensory response to capsaicin. Icilin also prevented mechanosensory desensitization and sensitization induced by capsaicin and the TRPA1 agonist AITC (40 μmol/L), respectively. TRPM8 is present on a select population of colonic high threshold sensory neurons, which may also co-express TRPV1. TRPM8 couples to TRPV1 and TRPA1 to inhibit their downstream chemosensory and mechanosensory actions. PMID:21489690

  20. The afferent pupillary defect in acute optic neuritis.

    PubMed Central

    Ellis, C J

    1979-01-01

    Twenty-two patients with acute optic neuritis were studied by the techniques of infrared pupillometry and visual evoked responses (VER) to pattern reversal. A relative afferent pupillary defect was found in all cases and the magnitude of this defect was found to be related to the amplitude, but not to the latency, of the VER. During follow-up the afferent defect was found to remain persistently abnormal while other methods of clinical evaluation could not demonstrate abnormality reliably. The amplitude of the VER also remained low. PMID:501365

  1. Launch Pad in a Box

    NASA Technical Reports Server (NTRS)

    Mantovani, J. G.; Tamasy, G. J.; Mueller, R. P.; Townsend, I. I.; Sampson, J. W.; Lane, M. A.

    2016-01-01

    NASA Kennedy Space Center (KSC) is developing a new deployable launch system capability to support a small class of launch vehicles for NASA and commercial space companies to test and launch their vehicles. The deployable launch pad concept was first demonstrated on a smaller scale at KSC in 2012 in support of NASA Johnson Space Center's Morpheus Lander Project. The main objective of the Morpheus Project was to test a prototype planetary lander as a vertical takeoff and landing test-bed for advanced spacecraft technologies using a hazard field that KSC had constructed at the Shuttle Landing Facility (SLF). A steel pad for launch or landing was constructed using a modular design that allowed it to be reconfigurable and expandable. A steel flame trench was designed as an optional module that could be easily inserted in place of any modular steel plate component. The concept of a transportable modular launch and landing pad may also be applicable to planetary surfaces where the effects of rocket exhaust plume on surface regolith is problematic for hardware on the surface that may either be damaged by direct impact of high speed dust particles, or impaired by the accumulation of dust (e.g., solar array panels and thermal radiators). During the Morpheus free flight campaign in 2013-14, KSC performed two studies related to rocket plume effects. One study compared four different thermal ablatives that were applied to the interior of a steel flame trench that KSC had designed and built. The second study monitored the erosion of a concrete landing pad following each landing of the Morpheus vehicle on the same pad located in the hazard field. All surfaces of a portable flame trench that could be directly exposed to hot gas during launch of the Morpheus vehicle were coated with four types of ablatives. All ablative products had been tested by NASA KSC and/or the manufacturer. The ablative thicknesses were measured periodically following the twelve Morpheus free flight tests

  2. Activation of PAD4 in NET formation.

    PubMed

    Rohrbach, Amanda S; Slade, Daniel J; Thompson, Paul R; Mowen, Kerri A

    2012-01-01

    Peptidylarginine deiminases, or PADs, convert arginine residues to the non-ribosomally encoded amino acid citrulline in a variety of protein substrates. PAD4 is expressed in granulocytes and is essential for the formation of neutrophil extracellular traps (NETs) via PAD4-mediated histone citrullination. Citrullination of histones is thought to promote NET formation by inducing chromatin decondensation and facilitating the expulsion of chromosomal DNA that is coated with antimicrobial molecules. Numerous stimuli have been reported to lead to PAD4 activation and NET formation. However, how this signaling process proceeds and how PAD4 becomes activated in cells is largely unknown. Herein, we describe the various stimuli and signaling pathways that have been implicated in PAD4 activation and NET formation, including the role of reactive oxygen species generation. To provide a foundation for the above discussion, we first describe PAD4 structure and function, and how these studies led to the development of PAD-specific inhibitors. A comprehensive survey of the receptors and signaling pathways that regulate PAD4 activation will be important for our understanding of innate immunity, and the identification of signaling intermediates in PAD4 activation may also lead to the generation of pharmaceuticals to target NET-related pathogenesis. PMID:23264775

  3. Impossible Dreams, Impossible Choices, and Thoughts about Depolarizing the Debate

    ERIC Educational Resources Information Center

    Morrow, Susan L.; Beckstead, A. Lee; Hayes, Jeffrey A.; Haldeman, Douglas C.

    2004-01-01

    The titles of the reactions to this major contribution alone set the stage for further exploration of the issues regarding the hopes and dreams of same-sex attracted (SSA) clients in religious conflict and their therapists, issues of choice, and whether or not it is possible - or even appropriate - to depolarize the current debate (Gonsiorek,…

  4. Depolarization Measurements with the High Spectral Resolution Lidar

    NASA Technical Reports Server (NTRS)

    Eloranta, E. W.; Piironen, P.

    1996-01-01

    This paper describes modifications to the University of Wisconsin High Spectral Resolution Lidar (HSRL) which permit very precise depolarization measurements in addition to optical depth, backscatter cross section, and extinction cross section measurements. Because HSRL separates the lidar return into aerosol and molecular contributions, they can be measured separately.

  5. Ca2+-Dependent Enhancement of Release by Subthreshold Somatic Depolarization

    PubMed Central

    Christie, Jason M.; Chiu, Delia N.; Jahr, Craig E.

    2010-01-01

    Summary In many neurons, subthreshold somatic depolarization can spread electrotonically into the axon and modulate subsequent spike-evoked transmission. Although release probability is regulated by intracellular Ca2+, the Ca2+-dependence of this modulatory mechanism has been debated. Using paired recordings from synaptically connected molecular-layer interneurons (MLIs) of the rat cerebellum, we observed Ca2+-mediated strengthening of release following brief subthreshold depolarization of the soma. Two-photon microscopy revealed that, at the axon, somatic depolarization evoked Ca2+ influx through voltage-sensitive Ca2+ channels (VSCCs) and facilitated spike-evoked Ca2+ entry. Exogenous Ca2+ buffering diminished these Ca2+ transients and eliminated the strengthening of release. Axonal Ca2+ entry elicited by subthreshold somatic depolarization also triggered asynchronous transmission that may deplete vesicle availability and thereby temper release strengthening. In this cerebellar circuit, activity-dependent presynaptic plasticity depends on Ca2+ elevations resulting from both sub- and suprathreshold electrical activity initiated at the soma. PMID:21170054

  6. Ice depolarization on low-angle 2 GHz satellite downlinks

    NASA Technical Reports Server (NTRS)

    Stutzman, W. L.; Bostian, C. W.; Tsolakis, A.; Pratt, T.

    1984-01-01

    The impact of ice depolarization on the statistical performance of satellite downlinks were investigated. Propagation data recorded during 1979 and 1980 to see what impact of ice depolarization on link performance were analyzed. The effects on the cross polarization discrimination (XPD) statistics amounted to at most a 2 to 4 dB reduction in the XPD values which rain would have produced for a given percentage of time. Ice depolarization had no effect on the statistics of XPD values below the 0.01% level. Most of the severe ice depolarization events were associated with drops in barometric pressure and the passage of intense cold fronts through our area. Ice contents as the product of three individually undetermined quantities were defined: ice particle density, ice cloud thickness, and the average volume of the ice crystals. It is indicated that populations of ice particle with ice contents on the order of 0.002 m4/m3 are probably responsible for the lower values of measured XPD.

  7. Lidar ratio and depolarization ratio for cirrus clouds.

    PubMed

    Chen, Wei-Nai; Chiang, Chih-Wei; Nee, Jan-Bai

    2002-10-20

    We report on studies of the lidar and the depolarization ratios for cirrus clouds. The optical depth and effective lidar ratio are derived from the transmission of clouds, which is determined by comparing the backscattering signals at the cloud base and cloud top. The lidar signals were fitted to a background atmospheric density profile outside the cloud region to warrant the linear response of the return signals with the scattering media. An average lidar ratio, 29 +/- 12 sr, has been found for all clouds measured in 1999 and 2000. The height and temperature dependences ofthe lidar ratio, the optical depth, and the depolarization ratio were investigated and compared with results of LITE and PROBE. Cirrus clouds detected near the tropopause are usually optically thin and mostly subvisual. Clouds with the largest optical depths were found near 12 km with a temperature of approximately -55 degrees C. The multiple-scattering effect is considered for clouds with high optical depths, and this effect lowers the lidar ratios compared with a single-scattering condition. Lidar ratios are in the 20-40 range for clouds at heights of 12.5-15 km and are smaller than approximately 30 in height above 15 km. Clouds are usually optically thin for temperatures below approximately -65 degrees C, and in this region the optical depth tends to decrease with height. The depolarization ratio is found to increase with a height at 11-15 km and smaller than 0.3 above 16 km. The variation in the depolarization ratio with the lidar ratio was also reported. The lidar and depolarization ratios were discussed in terms of the types of hexagonal ice crystals. PMID:12396200

  8. Ventral Tegmental Area Afferents and Drug-Dependent Behaviors

    PubMed Central

    Oliva, Idaira; Wanat, Matthew J.

    2016-01-01

    Drug-related behaviors in both humans and rodents are commonly thought to arise from aberrant learning processes. Preclinical studies demonstrate that the acquisition and expression of many drug-dependent behaviors involves the ventral tegmental area (VTA), a midbrain structure comprised of dopamine, GABA, and glutamate neurons. Drug experience alters the excitatory and inhibitory synaptic input onto VTA dopamine neurons, suggesting a critical role for VTA afferents in mediating the effects of drugs. In this review, we present evidence implicating the VTA in drug-related behaviors, highlight the diversity of neuronal populations in the VTA, and discuss the behavioral effects of selectively manipulating VTA afferents. Future experiments are needed to determine which VTA afferents and what neuronal populations in the VTA mediate specific drug-dependent behaviors. Further studies are also necessary for identifying the afferent-specific synaptic alterations onto dopamine and non-dopamine neurons in the VTA following drug administration. The identification of neural circuits and adaptations involved with drug-dependent behaviors can highlight potential neural targets for pharmacological and deep brain stimulation interventions to treat substance abuse disorders. PMID:27014097

  9. Changes in monkey horizontal semicircular canal afferent responses after spaceflight

    NASA Technical Reports Server (NTRS)

    Correia, M. J.; Perachio, A. A.; Dickman, J. D.; Kozlovskaia, I. B.; Sirota, M. G.; Iakushin, S. B.; Beloozerova, I. N.

    1992-01-01

    Extracellular responses from single horizontal semicircular canal afferents in two rhesus monkeys were studied after recovery from a 14-day biosatellite (Cosmos 2044) orbital spaceflight. On the 1st postflight day, the mean gain for 9 different horizontal canal afferents, tested using one or several different passive yaw rotation waveforms, was nearly twice that for 20 horizontal canal afferents similarly tested during preflight and postflight control studies. Adaptation of the afferent response to passive yaw rotation on the 1st postflight day was also greater. These results suggest that at least one component of the vestibular end organ (the semicircular canals) is transiently modified after exposure to 14 days of microgravity. It is unclear whether the changes are secondary to other effects of microgravity, such as calcium loss, or an adaptive response. If the response is adaptive, then this report is the first evidence that the response of the vestibular end organ may be modified (presumably by the central nervous system via efferent connections) after prolonged unusual vestibular stimulation. If this is the case, the sites of plasticity of vestibular responses may not be exclusively within central nervous system vestibular structures, as previously believed.

  10. PAD in women: the ischemic continuum.

    PubMed

    Pollak, Amy West

    2015-06-01

    Lower extremity peripheral arterial disease (PAD) is part of the ischemic continuum of atherosclerotic vascular disease and is associated with an increased risk of myocardial infarction, stroke, and cardiovascular death. Compared to men, women with PAD are more likely to have asymptomatic disease or atypical symptoms. PAD in women is associated with decreased exercise capacity, reduced quality of life, increased risk of depression, as well as a greater risk of acute cardiovascular events and cardiovascular mortality than male counterparts. Ensuring an appropriate diagnosis of women with PAD offers an opportunity to begin risk factor modification therapy, improve walking capacity and make a timely referral for revascularization if needed. It is critical to highlight the sex-based disparities in lower extremity PAD so that we may work to improve outcomes for women with PAD. PMID:25939674

  11. Cantilever mounted resilient pad gas bearing

    NASA Technical Reports Server (NTRS)

    Etsion, I. (Inventor)

    1978-01-01

    A gas-lubricated bearing is described, employing at least one pad mounted on a rectangular cantilever beam to produce a lubricating wedge between the face of the pad and a moving surface. The load-carrying and stiffness characteristics of the pad are related to the dimensions and modulus of elasticity of the beam. The bearing is applicable to a wide variety of types of hydrodynamic bearings.

  12. Neck muscle afferents influence oromotor and cardiorespiratory brainstem neural circuits.

    PubMed

    Edwards, I J; Lall, V K; Paton, J F; Yanagawa, Y; Szabo, G; Deuchars, S A; Deuchars, J

    2015-01-01

    Sensory information arising from the upper neck is important in the reflex control of posture and eye position. It has also been linked to the autonomic control of the cardiovascular and respiratory systems. Whiplash associated disorders (WAD) and cervical dystonia, which involve disturbance to the neck region, can often present with abnormalities to the oromotor, respiratory and cardiovascular systems. We investigated the potential neural pathways underlying such symptoms. Simulating neck afferent activity by electrical stimulation of the second cervical nerve in a working heart brainstem preparation (WHBP) altered the pattern of central respiratory drive and increased perfusion pressure. Tracing central targets of these sensory afferents revealed projections to the intermedius nucleus of the medulla (InM). These anterogradely labelled afferents co-localised with parvalbumin and vesicular glutamate transporter 1 indicating that they are proprioceptive. Anterograde tracing from the InM identified projections to brain regions involved in respiratory, cardiovascular, postural and oro-facial behaviours--the neighbouring hypoglossal nucleus, facial and motor trigeminal nuclei, parabrachial nuclei, rostral and caudal ventrolateral medulla and nucleus ambiguus. In brain slices, electrical stimulation of afferent fibre tracts lateral to the cuneate nucleus monosynaptically excited InM neurones. Direct stimulation of the InM in the WHBP mimicked the response of second cervical nerve stimulation. These results provide evidence of pathways linking upper cervical sensory afferents with CNS areas involved in autonomic and oromotor control, via the InM. Disruption of these neuronal pathways could, therefore, explain the dysphagic and cardiorespiratory abnormalities which may accompany cervical dystonia and WAD. PMID:24595534

  13. Malaria: the value of the automated depolarization analysis.

    PubMed

    Josephine, F P; Nissapatorn, V

    2005-01-01

    This retrospective and descriptive study was carried out in the University of Malaya Medical Center (UMMC) from January to September, 2004. This study aimed to evaluate the diagnostic utility of the Cell-Dyn 4000 hematology analyzer's depolarization analysis and to determine the sensitivity and specificity of this technique in the context of malaria diagnosis. A total of 889 cases presenting with pyrexia of unknown origin or clinically suspected of malaria were examined. Sixteen of these blood samples were found to be positive; 12 for P. vivax, 3 for P. malariae, and 1 for P. falciparum by peripheral blood smear as the standard technique for parasite detection and species identification. Demographic characteristics showed that the majority of patients were in the age range of 20-57 with a mean of 35.9 (+/- SD) 11.4 years, and male foreign workers. Of these, 16 positive blood samples were also processed by Cell-Dyne 4000 analyzer in the normal complete blood count (CBC) operational mode. Malaria parasites produce hemozoin, which depolarizes light and this allows the automated detection of malaria during routine complete blood count analysis with the Abbot Cell-Dyn CD4000 instrument. The white blood cell (WBC) differential plots of all malaria positive samples showed abnormal depolarization events in the NEU-EOS and EOS I plots. This was not seen in the negative samples. In 12 patients with P. vivax infection, a cluster pattern in the Neu-EOS and EOS I plots was observed, and appeared color-coded green or black. In 3 patients with P. malariae infection, few random depolarization events in the NEU-EOS and EOS I plots were seen, and appeared color-coded green, black or blue. While in the patient with P. falciparum infection, the sample was color-coded green with a few random purple depolarizing events in the NEU-EOS and EOS I plots. This study confirms that automated depolarization analysis is a highly sensitive and specific method to diagnose whether or not a patient

  14. Overcoming an intrinsic depolarizing resonance with a partial snake at the Brookhaven AGS.

    SciTech Connect

    Huang, H.; Ahrens, L.; Bai, M.; Brown, K. A.; Glenn, W.; Luccio, A. U.; MacKay, W. W.; Montag, C.; Ptitsyn, V.; Roser, T.; Tsoupas, N.; Zeno, K.; Ranjbar, V.; Cadman, R. V.; Spinka, H.; Underwood, D.; High Energy Physics; BNL; Indiana Univ.

    2004-06-01

    An 11.4% partial Siberian snake was used to successfully accelerate polarized protons through a strong intrinsic depolarizing spin resonance in the Alternating Gradient Synchrotron (AGS). No noticeable depolarization was observed. This opens up the possibility of using a 20% to 30% partial Siberian snake in the AGS or other medium energy proton synchrotrons to overcome all weak and strong depolarizing spin resonances.

  15. Quantum stabilizer codes for correlated and asymmetric depolarizing errors

    SciTech Connect

    Cafaro, Carlo; Mancini, Stefano

    2010-07-15

    We study the performance of common quantum stabilizer codes in the presence of asymmetric and correlated errors. Specifically, we consider the depolarizing noisy quantum memory channel and perform quantum error correction via the five- and seven-qubit stabilizer codes. We characterize these codes by means of the entanglement fidelity as a function of the error probability and the degree of memory. We show that their performances are lowered by the presence of correlations, and we compute the error probability threshold values for code effectiveness. Furthermore, we uncover that the asymmetry in the error probabilities does not affect the performance of the five-qubit code, while it does affect the performance of the seven-qubit code, which results in being less effective when considering correlated and symmetric depolarizing errors but more effective for correlated and asymmetric errors.

  16. Ileal bladder substitute: antireflux nipple or afferent tubular segment?

    PubMed

    Studer, U E; Spiegel, T; Casanova, G A; Springer, J; Gerber, E; Ackermann, D K; Gurtner, F; Zingg, E J

    1991-01-01

    Spheroidal bladder substitutes made from double-folded ileal segments, similar to Goodwin's cup-patch technique, are devoid of major coordinated wall contractions. This, together with the reservoir's direct anastomosis to the membranous urethra, prevents major intraluminal pressure peaks and assures a residue-free voiding of sterile urine. In order to determine whether, under these conditions, an afferent tubular isoperistaltic ileal segment of 20-cm length protects the upper urinary tract as efficiently as an antireflux nipple, 60 male patients who were subjected to radical cystectomy were prospectively randomised to groups in which a bladder substitute was formed together with either of these 2 antireflux devices. An analysis of the results obtained in 20 patients from each group who could be followed for more than 1 year (median observation time 30 and 36 months) showed no differences between the groups in metabolic disturbances, kidney size, reservoir capacity, diurnal and nocturnal urinary continence, the incidence of urinary tract infection or episodes of acute pyelonephritis. Later than 1 year postoperatively, intravenous urograms of the renoureteral units of 25% of the patients with antireflux nipples showed persistent but generally slight dilatation of the upper urinary tracts. This observation was significantly more frequent than it was in patients with afferent tubular segments. Urodynamic and radiographic studies showed that the competence of the antireflux nipples was secured by the raised surrounding intravesical pressure. This, however, also resulted in a transient functional obstruction, and a gradual rise of the basal pressure in the upper urinary tracts was recorded. In patients with afferent ileal tubular segments, contrast medium could be forced upwards into the renal pelvis when the bladder substitutes were overfilled. However, despite raised intravesical pressures, peristalsis in the isoperistaltic afferent tubular segment gradually returned

  17. Atmospheric Depolarization Lidar Experimental Receiver: A Space Shuttle Hitchhiker Payload

    NASA Technical Reports Server (NTRS)

    McGill, Matthew J.; Scott, V. Stanley; Spinhirne, James D.

    1998-01-01

    Development work is underway at the Goddard Space Flight Center to construct a depolarization measuring atmospheric lidar receiver. The Atmospheric Lidar (AL) is tentatively scheduled to fly on the Space Shuttle in a late-1999 time frame. The AL will fly in conjunction with the Shuttle Laser Altimeter (SLA) and the Infrared Spectral Imaging Radiometer (ISIR) to provide a comprehensive package of atmospheric aerosol and cloud information. The AL operates in conjunction with the SLA laser transmitter and measures profiles of atmospheric backscatter at 532 nm. The receiver system discriminates between the parallel and perpendicular polarizations of the backscattered signal, thus providing depolarization ratios for scattering from clouds. The lidar receiver also provides cloud height and thickness measurements to complement the brightness temperature measurements generated by the ISIR thermal imager. The function of the AL is twofold. The primary function is to provide range-resolved measurements of atmospheric aerosol backscatter and depolarization ratio at 532 nm with 75 m vertical resolution. The scientific purpose of these measurements is to determine composition of clouds based on the depolarization ratio (i.e cloud content is water or ice), to determine cloud height and thickness, and to gain further understanding of the global distribution of aerosols. This information, when coupled with the cloud brightness measured by the ISIR thermal imager will provide a significant amount of information on cloud composition and radiative effects, particularly for cirrus and sub-visual cirrus clouds. A secondary function of the AL is to serve as an in-space test bed for lidar technology advancements, including a fully fiber-coupled receiver and photon counting from space. In addition, the data obtained by the AL will be used to develop software for the Geoscience Laser Altimeter System (GLAS) flight mission.

  18. Learning Chinese Idioms through iPads

    ERIC Educational Resources Information Center

    Yang, Chunsheng; Xie, Ying

    2013-01-01

    This paper reports on an action research study using iPads during the teaching of Chinese idioms to heritage learners. A class of 12 second-year Chinese learners were engaged in a self-generated learning process focused on learning abstract and concrete idioms using iPads. Students' short-term and long-term learning was measured; feedback…

  19. STS-135 Launch Pad Lightning Strike

    NASA Video Gallery

    A pair of lightning strikes occurred near launch pad 39-A at NASA's Kennedy Space Center at 12:31 p.m. and 12:40 p.m. EDT on July 7. The first struck the water tower 515 feet from the pad and the s...

  20. Taking the iPad's Measure

    ERIC Educational Resources Information Center

    Raths, David

    2012-01-01

    Soon after the iPad's release in 2010, several universities decided to issue the devices to all incoming freshmen. At the time, critics scoffed at the moves as little more than marketing gimmicks designed to attract students. In truth, few of the schools required instructors to design curriculum around the iPad or had specific plans to measure…

  1. First Graders with iPads?

    ERIC Educational Resources Information Center

    Getting, Sara; Swainey, Karin

    2012-01-01

    Giving iPads to first graders is a leap of faith that many teachers are understandably hesitant to take, especially if their students need immediate reading intervention and school leaders want guaranteed results. This article discusses how the authors took on the challenge of improving elementary reading using iPads, found surprising success for…

  2. Using iPads to Your Advantage

    ERIC Educational Resources Information Center

    Zakrzewski, Jennifer L.

    2016-01-01

    In this article, middle school mathematics teacher Jennifer Zakrzewski describes how she successfully incorporated iPads and Apple TV (for projection of iPad screens) into her classroom while having her students solve a problem about mangoes. As Zakrzewski began a unit on multiplying and dividing fractions, she chose to start with the Mangoes…

  3. Elastodynamic metasurface: Depolarization of mechanical waves and time effects

    SciTech Connect

    Boutin, Claude; Schwan, Logan; Dietz, Matthew S.

    2015-02-14

    We report the concept of microstructured surfaces with inner resonance in the field of elastodynamics, so-called elastodynamic metasurfaces. Such metasurfaces allow for wavefield manipulation of mechanical waves by tuning the boundary conditions at specific frequencies. In particular, they can be used to depolarize elastic waves without introducing heterogeneities in the medium itself; the physical means to do so in homogeneous elastic media used to remain, surprisingly, an open question while depolarization is commonplace in electromagnetism. The principle relies on the anisotropic behaviour of a subwavelength array of resonators: Their subwavelength configuration confines the Bragg interferences scattered by resonators into a boundary layer. The effective behaviour of the resonating array is expressed with homogenization as an unconventional impedance, the frequency-dependence, and anisotropy of which lead to depolarization and time effects. The concept of the elastodynamic metasurface is tested experimentally and results bear testament to its efficacy and robustness. Elastodynamic metasurfaces are easily realized and analytically predictable, opening new possibilities in tomography techniques, ultrasonics, geophysics, vibration control, materials and structure design.

  4. Dual Double-Wedge Pseudo-Depolarizer with Anamorphic PSF

    NASA Technical Reports Server (NTRS)

    Hill, Peter; Thompson, Patrick

    2012-01-01

    A polarized scene, which may occur at oblique illumination angles, creates a radiometric signal that varies as a function of viewing angle. One common optical component that is used to minimize such an effect is a polarization scrambler or depolarizer. As part of the CLARREO mission, the SOLARIS instrument project at Goddard Space Flight Center has developed a new class of polarization scramblers using a dual double-wedge pseudo-depolarizer that produces an anamorphic point spread function (PSF). The SOLARIS instrument uses two Wollaston type scramblers in series, each with a distinct wedge angle, to image a pseudo-depolarized scene that is free of eigenstates. Since each wedge is distinct, the scrambler is able to produce an anamorphic PSF that maintains high spatial resolution in one dimension by sacrificing the spatial resolution in the other dimension. This scrambler geometry is ideal for 1-D imagers, such as pushbroom slit spectrometers, which require high spectral resolution, high spatial resolution, and low sensitivity to polarized light. Moreover, the geometry is applicable to a wide range of scientific instruments that require both high SNR (signal-to-noise ratio) and low sensitivity to polarized scenes

  5. Multiple scattering depolarization in marine stratus clouds: Lidar experiments

    NASA Technical Reports Server (NTRS)

    Sassen, K.; Petrilla, R. L.

    1986-01-01

    The depolarization of ruby lidar backscattering caused by multiple scattering in marine stratus clouds was examined systematically from a field site on the southern California coast. Investigated were the effects on the linear depolarization (delta) of lidar receiver field of view (FOV), elevation angle and laser beam pointing errors. An approximately linear increase in maximum delta values was observed with increasing receiver FOV, and the importance of accurate transmitter/receiver beam alignment was demonstrated during experiments in which the laser axis was deliberately misaligned. An elevation angle dependence to the delta values was observed as a consequence of the natural vertical inhomogeneity of water cloud content above the cloud base. Time histories of the depolarization characteristics of dissipating stratus clouds revealed significant spatial and temporal variability in delta values attributed to cloud composition variations. Employing a 1 mrad transmitter FOV, maximum delta values of 0.21 nd 0.33 were observed with 1 and 3 mrad receiver FOVs, respectively, from the low stratus clouds. The fundamental causes and effects on the lidar equation of multiple scattering are also discussed.

  6. Elastodynamic metasurface: Depolarization of mechanical waves and time effects

    NASA Astrophysics Data System (ADS)

    Boutin, Claude; Schwan, Logan; Dietz, Matthew S.

    2015-02-01

    We report the concept of microstructured surfaces with inner resonance in the field of elastodynamics, so-called elastodynamic metasurfaces. Such metasurfaces allow for wavefield manipulation of mechanical waves by tuning the boundary conditions at specific frequencies. In particular, they can be used to depolarize elastic waves without introducing heterogeneities in the medium itself; the physical means to do so in homogeneous elastic media used to remain, surprisingly, an open question while depolarization is commonplace in electromagnetism. The principle relies on the anisotropic behaviour of a subwavelength array of resonators: Their subwavelength configuration confines the Bragg interferences scattered by resonators into a boundary layer. The effective behaviour of the resonating array is expressed with homogenization as an unconventional impedance, the frequency-dependence, and anisotropy of which lead to depolarization and time effects. The concept of the elastodynamic metasurface is tested experimentally and results bear testament to its efficacy and robustness. Elastodynamic metasurfaces are easily realized and analytically predictable, opening new possibilities in tomography techniques, ultrasonics, geophysics, vibration control, materials and structure design.

  7. Spontaneous recovery from depolarizing drugs in rat diaphragm.

    PubMed Central

    Creese, R; Mitchell, L D

    1981-01-01

    1. The end-plate region in surface fibres of rat diaphragm was located by the use of polarizing filters. 2. Carbachol (100 microM) produced depolarization at the end-plate to -55 mV, as shown by continuous recording, with some indication of spontaneous recovery in the presence of the drug. The miniature end-plate potentials disappeared and remained absent. 3. By repeated sampling it was found that the resting potential at the end-plate had largely recovered after 45 min in the presence of carbachol. Individual fibres showed much variation in the rate of recovery, and in some fibres the repolarization was rapid. 4. In the absence of K, carbachol produced depolarization at the end-plate without significant recovery, as shown by repeated sampling. 5. When muscles were exposed to ouabain (100 microM) in addition to carbachol the end-plate remained depolarized without recovery for 60 min. The effect of ouabain was reversible: withdrawal of ouabain (in the presence of carbachol) led to substantial recovery. 6. Suberyldicholine (100 microM) gave results which were similar to those produced by carbachol. 7. It was inferred that the spontaneous recovery of membrane potential in the presence of carbachol and of suberyldicholine is a process which is sensitive to K and to ouabain. Images Plate 1 PMID:7277216

  8. Redstone Missile on Launch Pad

    NASA Technical Reports Server (NTRS)

    1958-01-01

    Redstone missile No. 1002 on the launch pad at Cape Canaveral, Florida, on May 16, 1958. The Redstone ballistic missile was a high-accuracy, liquid-propelled, surface-to-surface missile developed by the Army Ballistic Missile Agency, Redstone Arsenal, in Huntsville, Alabama, under the direction of Dr. von Braun. The Redstone engine was a modified and improved version of the Air Force's Navaho cruise missile engine of the late forties. The A-series, as this would be known, utilized a cylindrical combustion chamber as compared with the bulky, spherical V-2 chamber. By 1951, the Army was moving rapidly toward the design of the Redstone missile, and production was begun in 1952. Redstone rockets became the 'reliable workhorse' for America's early space program. As an example of the versatility, Redstone was utilized in the booster for Explorer 1, the first American satellite, with no major changes to the engine or missile

  9. Lateral pharyngeal fat pad pressure during breathing.

    PubMed

    Winter, W C; Gampper, T; Gay, S B; Suratt, P M

    1996-12-01

    The purpose of this study was to test whether pressure in tissue lateral to the upper airway, the lateral pharyngeal fat pad, differs from atmospheric and pharyngeal pressure and whether it changes with breathing. We studied five male pigs by inserting a transducer-tipped catheter into their fat pad space using computed tomography (CT) scan guidance. We measured airflow with a pneumotachograph attached to a face mask and pharyngeal pressure with a balloon catheter. Fat pad pressure correlated positively with airflow and with pharyngeal pressure, decreasing during inspiration and increasing during expiration. Pressure in the fat pad differed from atmospheric pressure, generally exceeding it, and from pharyngeal pressure. We conclude that lateral pharyngeal fat pad pressure differs from atmospheric and pharyngeal pressure and that it changes with breathing. PMID:9085504

  10. Identification of Molecular Pathologies Sufficient to Cause Neuropathic Excitability in Primary Somatosensory Afferents Using Dynamical Systems Theory

    PubMed Central

    Rho, Young-Ah; Prescott, Steven A.

    2012-01-01

    Pain caused by nerve injury (i.e. neuropathic pain) is associated with development of neuronal hyperexcitability at several points along the pain pathway. Within primary afferents, numerous injury-induced changes have been identified but it remains unclear which molecular changes are necessary and sufficient to explain cellular hyperexcitability. To investigate this, we built computational models that reproduce the switch from a normal spiking pattern characterized by a single spike at the onset of depolarization to a neuropathic one characterized by repetitive spiking throughout depolarization. Parameter changes that were sufficient to switch the spiking pattern also enabled membrane potential oscillations and bursting, suggesting that all three pathological changes are mechanistically linked. Dynamical analysis confirmed this prediction by showing that excitability changes co-develop when the nonlinear mechanism responsible for spike initiation switches from a quasi-separatrix-crossing to a subcritical Hopf bifurcation. This switch stems from biophysical changes that bias competition between oppositely directed fast- and slow-activating conductances operating at subthreshold potentials. Competition between activation and inactivation of a single conductance can be similarly biased with equivalent consequences for excitability. “Bias” can arise from a multitude of molecular changes occurring alone or in combination; in the latter case, changes can add or offset one another. Thus, our results identify pathological change in the nonlinear interaction between processes affecting spike initiation as the critical determinant of how simple injury-induced changes at the molecular level manifest complex excitability changes at the cellular level. We demonstrate that multiple distinct molecular changes are sufficient to produce neuropathic changes in excitability; however, given that nerve injury elicits numerous molecular changes that may be individually sufficient to

  11. Central changes in primary afferent fibers following peripheral nerve lesions.

    PubMed

    Coggeshall, R E; Lekan, H A; Doubell, T P; Allchorne, A; Woolf, C J

    1997-04-01

    Cutting or crushing rat sciatic nerve does not significantly reduce the number of central myelinated sensory axons in the dorsal roots entering the fourth and fifth lumbar segments even over very extended periods of time. Unmyelinated axons were reduced by approximately 50%, but only long after sciatic nerve lesions (four to eight months), and reinnervation of the peripheral target did not rescue these axons. This indicates that a peripheral nerve lesion sets up a slowly developing but major shift towards large afferent fiber domination of primary afferent input into the spinal cord. In addition, since myelinated axons are never lost, this is good evidence that the cells that give rise to these fibers are also not lost. If this is the case, this would indicate that adult primary sensory neurons with myelinated axons do not depend on peripheral target innervation for survival. PMID:9130791

  12. Afferent projections to the deep mesencephalic nucleus in the rat

    SciTech Connect

    Veazey, R.B.; Severin, C.M.

    1982-01-10

    Afferent projections to the deep mesencephalic nucleus (DMN) of the rat were demonstrated with axonal transport techniques. Potential sources for projections to the DMN were first identified by injecting the nucleus with HRP and examining the cervical spinal cord, brain stem, and cortex for retrogradely labeled neurons. Areas consistently labeled were then injected with a tritiated radioisotope, the tissue processed for autoradiography, and the DMN examined for anterograde labeling. Afferent projections to the medial and/or lateral parts of the DMN were found to originate from a number of spinal, bulbar, and cortical centers. Rostral brain centers projecting to both medial and lateral parts of the DMN include the ipsilateral motor and somatosensory cortex, the entopeduncular nucleus, and zona incerta. at the level of the midbrain, the ipsilateral substantia nigra and contralateral DMN likewise project to the DMN. Furthermore, the ipsilateral superior colliculus projects to the DMN, involving mainly the lateral part of the nucleus. Afferents from caudal centers include bilateral projections from the sensory nucleus of the trigeminal complex and the nucleus medulla oblongata centralis, as well as from the contralateral dentate nucleus. The projections from the trigeminal complex and nucleus medullae oblongatae centralis terminate in the intermediate and medial parts of the DMN, whereas projections from the contralateral dentate nucleus terminate mainly in its lateral part. In general, the afferent connections of the DMN arise from diverse areas of the brain. Although most of these projections distribute throughout the entire extent of the DMN, some of them project mainly to either medial or lateral parts of the nucleus, thus suggesting that the organization of the DMN is comparable, at least in part, to that of the reticular formation of the pons and medulla, a region in which hodological differences between medial and lateral subdivisions are known to exist.

  13. Enhanced Muscle Afferent Signals during Motor Learning in Humans.

    PubMed

    Dimitriou, Michael

    2016-04-25

    Much has been revealed concerning human motor learning at the behavioral level [1, 2], but less is known about changes in the involved neural circuits and signals. By examining muscle spindle responses during a classic visuomotor adaptation task [3-6] performed by fully alert humans, I found substantial modulation of sensory afferent signals as a function of adaptation state. Specifically, spindle control was independent of concurrent muscle activity but was specific to movement direction (representing muscle lengthening versus shortening) and to different stages of learning. Increased spindle afferent responses to muscle stretch occurring early during learning reflected individual error size and were negatively related to subsequent antagonist activity (i.e., 60-80 ms thereafter). Relative increases in tonic afferent output early during learning were predictive of the subjects' adaptation rate. I also found that independent spindle control during sensory realignment (the "washout" stage) induced afferent signal "linearization" with respect to muscle length (i.e., signals were more tuned to hand position). The results demonstrate for the first time that motor learning also involves independent and state-related modulation of sensory mechanoreceptor signals. The current findings suggest that adaptive motor performance also relies on the independent control of sensors, not just of muscles. I propose that the "γ" motor system innervating spindles acts to facilitate the acquisition and extraction of task-relevant information at the early stages of sensorimotor adaptation. This designates a more active and targeted role for the human proprioceptive system during motor learning. PMID:27040776

  14. Polarization changes at Lyot depolarizer output for different types of input beams.

    PubMed

    de Sande, J Carlos G; Piquero, Gemma; Teijeiro, Cristina

    2012-03-01

    Lyot depolarizers are optical devices made of birefringent materials used for producing unpolarized beams from totally polarized incident light. The depolarization is produced for polychromatic input beams due to the different phase introduced by the Lyot depolarizer for each wavelength. The effect of this device on other types of incident fields is investigated. In particular two cases are analyzed: (i) monochromatic and nonuniformly polarized incident beams and (ii) incident light synthesized by superposition of two monochromatic orthogonally polarized beams with different wavelengths. In the last case, it is theoretically and experimentally shown that the Lyot depolarizer increases the degree of polarization instead of depolarizes. PMID:22472758

  15. Endothelin-1 induced desensitization in primary afferent neurons

    PubMed Central

    Smith, Terika P.; Smith, Sherika N.; Sweitzer, Sarah M.

    2014-01-01

    Endothelin-1 (ET-1) is a known algogen that causes acute pain and sensitization in humans and spontaneous nociceptive behaviors when injected into the periphery in rats, and is elevated during vaso-occlusive episodes (VOEs) in sickle cell disease (SCD) patients. Previously, our lab has shown that a priming dose of ET-1 produces sensitization to capsaicin-induce secondary hyperalgesia. The goal of this study was to determine if the sensitization induced by ET-1 priming is occurring at the level of the primary afferent neuron. Calcium imaging in cultured dorsal root ganglion (DRG) neurons was utilized to examine the effects of ET-1 on primary afferent neurons. ET-1 induces [Ca2+]i transients in unprimed cells. ET-1 induced [Ca2+]i transients are attenuated by priming with ET-1. This priming effect occurs whether the priming dose is given 0-4 days prior to the challenge dose. Similarly, ET-1 priming decreases capsaicin-induced [Ca2+]i transients. At the level of the primary afferent neuron, ET-1 priming has a desensitizing effect on challenge exposures to ET-1 and capsaicin. PMID:25220703

  16. Vagal afferents, diaphragm fatigue, and inspiratory resistance in anesthetized dogs.

    PubMed

    Adams, J M; Farkas, G A; Rochester, D F

    1988-06-01

    This study tests three hypotheses regarding mechanisms that produce rapid shallow breathing during a severe inspiratory resistive load (IRL): 1) an intact vagal afferent pathway is necessary; 2) diaphragm fatigue contributes to tachypnea; and 3) hypoxia may alter the pattern of respiration. We imposed a severe IRL on pentobarbital sodium-anesthetized dogs, followed by bilateral vagotomy, then by supplemental O2. IRL alone produced rapid shallow breathing associated with hypercapnia and hypoxia. After the vagotomy, the breathing pattern became slow and deep, restoring arterial PCO2 but not arterial PO2 toward the control values. Relief of hypoxia had no effect, and at no time was there any evidence of fatigue of the diaphragm as measured by the response to phrenic nerve stimulation. We conclude that an intact afferent vagal pathway is necessary for the tachypnea resulting from a severe IRL, neither hypoxia nor diaphragm fatigue played a role, and, although we cannot rule out stimulation of vagal afferents, the simplest explanation for the increased frequency in our experiments is increased respiratory drive due to hypercapnia. PMID:3136122

  17. Subcortical afferent connections of the amygdala in the monkey

    NASA Technical Reports Server (NTRS)

    Mehler, W. R.

    1980-01-01

    The cells of origin of the afferent connections of the amygdala in the rhesus and squirrel monkeys are determined according to the retrograde axonal transport of the enzyme horseradish peroxidase injected into various quadrants of the amygdala. Analysis of the distribution of enzyme-labeled cells reveals afferent amygdalar connections with the ipsilateral halves of the midline nucleus paraventricularis thalami and both the parvo- and magnocellular parts of the nucleus subparafascicularis in the dorsal thalamus, all the subdivisions of the midline nucleus centralis complex, the nucleus reuniens ventralis and the nucleus interventralis. The largest populations of enzyme-labeled cells in the hypothalamus are found to lie in the middle and posterior parts of the ipsilateral, lateral hypothalamus and the ventromedial hypothalamic nucleus, with scattered cells in the supramammillary and dorsomedial nuclei and the posterior hypothalamic area, Tsai's ventral tegmental area, the rostral and caudal subdivisions of the nucleus linearis in the midbrain and the dorsal raphe nucleus. The most conspicuous subdiencephalic source of amygdalar afferent connections is observed to be the pars lateralis of the nucleus parabrachialis in the dorsolateral pontine tegmentum, with a few labeled cells differentiated from pigmented cells in the locus coeruleus.

  18. Transfer characteristics of the hair cell's afferent synapse

    NASA Astrophysics Data System (ADS)

    Keen, Erica C.; Hudspeth, A. J.

    2006-04-01

    The sense of hearing depends on fast, finely graded neurotransmission at the ribbon synapses connecting hair cells to afferent nerve fibers. The processing that occurs at this first chemical synapse in the auditory pathway determines the quality and extent of the information conveyed to the central nervous system. Knowledge of the synapse's input-output function is therefore essential for understanding how auditory stimuli are encoded. To investigate the transfer function at the hair cell's synapse, we developed a preparation of the bullfrog's amphibian papilla. In the portion of this receptor organ representing stimuli of 400-800 Hz, each afferent nerve fiber forms several synaptic terminals onto one to three hair cells. By performing simultaneous voltage-clamp recordings from presynaptic hair cells and postsynaptic afferent fibers, we established that the rate of evoked vesicle release, as determined from the average postsynaptic current, depends linearly on the amplitude of the presynaptic Ca2+ current. This result implies that, for receptor potentials in the physiological range, the hair cell's synapse transmits information with high fidelity. auditory system | exocytosis | glutamate | ribbon synapse | synaptic vesicle

  19. On the nature of the afferent fibers of oculomotor nerve.

    PubMed

    Manni, E; Draicchio, F; Pettorossi, V E; Carobi, C; Grassi, S; Bortolami, R; Lucchi, M L

    1989-03-01

    The oculogyric nerves contain afferent fibers originating from the ophthalmic territory, the somata of which are located in the ipsilateral semilunar ganglion. These primary sensory neurons project to the Subnucleus Gelatinosus of the Nucleus Caudalis Trigemini, where they make presynaptic contact with the central endings of the primary trigeminal afferents running in the fifth cranial nerve. After complete section of the trigeminal root, the antidromic volleys elicited in the trunk of the third cranial nerve by stimulating SG of NCT consisted of two waves belonging to the A delta and C groups. The area of both components of the antidromic volleys decreased both after bradykinin and hystamine injection into the corresponding cutaneous region and after thermic stimulation of the ipsilateral trigeminal ophthalmic territory. The reduction of such potentials can be explained in terms of collision between the antidromic volleys and those elicited orthodromically by chemical and thermic stimulation. Also, capsaicin applied on the nerve induced an immediate increase, followed by a long lasting decrease, of orthodromic evoked response area. These findings bring further support to the nociceptive nature of the afferent fibers running into the oculomotor nerve. PMID:2719524

  20. Neck afferent involvement in cardiovascular control during movement

    NASA Technical Reports Server (NTRS)

    Bolton, P. S.; Ray, C. A.

    2000-01-01

    It is well established that labyrinth and neck afferent information contributes to the regulation of somatomotor function during movement and changes in posture. There is also convincing evidence that the vestibular system participates in the modulation of sympathetic outflow and cardiovascular function during changes in posture, presumably to prevent orthostatic hypotension. However, the labyrinth organs do not provide any signals concerning body movements with respect to the head. In contrast, the neck receptors, particularly muscle spindles, are well located and suited to provide information about changes in body position with respect to the head and vestibular signals. Studies in the cat suggest that neck afferent information may modulate the vestibulosympathetic reflex responses to head-neck movements. There is some evidence in the cat to suggest involvement of low threshold mechanoreceptors. However, human studies do not indicate that low threshold mechanoreceptors in the neck modulate cardiovascular responses. The human studies are consistent with the studies in the cat in that they demonstrate the importance of otolith activation in mediating cardiovascular and sympathetic responses to changes in posture. This paper briefly reviews the current experimental evidence concerning the involvement of neck afferent information in the modulation of cardiovascular control during movement and changes in posture.

  1. Vestibular afferent responses to linear accelerations in the alert squirrel monkey

    NASA Technical Reports Server (NTRS)

    Somps, Christopher J.; Schor, Robert H.; Tomko, David L.

    1994-01-01

    The spontaneous activity of 40 otolith afferents and 44 canal afferents was recorded in 4 alert, intact squirrel monkeys. Polarization vectors and response properties of otolith afferents were determined during static re-orientations relative to gravity and during Earth-horizontal, sinusoidal, linear oscillations. Canal afferents were tested for sensitivity to linear accelerations. For regular otolith afferents, a significant correlation between upright discharge rate and sensitivity to dynamic acceleration in the horizontal plane was observed. This correlation was not present in irregular units. The sensitivity of otolith afferents to both static tilts and dynamic linear acceleration was much greater in irregularly discharging units than in regularly discharging units. The spontaneous activity and static and dynamic response properties of regularly discharging otolith afferents were similar to those reported in barbiturate-anesthetized squirrel monkeys. Irregular afferents also had similar dynamic response properties when compared to anesthetized monkeys. However, this sample of irregular afferents in alert animals had higher resting discharge rates and greater sensitivity to static tilts. The majority of otolith polarization vectors were oriented near the horizontal in the plane of the utricular maculae; however, directions of maximum sensitivity were different during dynamic and static testing. Canal afferents were not sensitive to static tilts or linear oscillations of the head.

  2. Characterization of Mouse Lumbar Splanchnic and Pelvic Nerve Urinary Bladder Mechanosensory Afferents

    PubMed Central

    Xu, Linjing; Gebhart, G. F.

    2009-01-01

    Sensory information from the urinary bladder is conveyed via lumbar splanchnic (LSN) and sacral pelvic (PN) nerves to the spinal cord. In the present report we compared the mechanosensitive properties of single afferent fibers in these two pathways using an in vitro mouse bladder preparation. Mechanosensitive primary afferents were recorded from the LSN or PN and distinguished based on their response to receptive field stimulation with different mechanical stimuli: probing (160 mg to 2 g), stretch (1–25 g), and stroking of the urothelium (10–1,000 mg). Four different classes of afferent were recorded from the LSN and PN: serosal, muscular, muscular/urothielial, and urothelial. The LSN contained principally serosal and muscular afferents (97% of the total sample), whereas all four afferent classes of afferent were present in the PN (63% of which were muscular afferents). In addition, the respective proportions and receptive field distributions differed between the two pathways. Both low- and high-threshold stretch-sensitive muscular afferents were present in both pathways, and muscular afferents in the PN were shown to sensitize after exposure to an inflammatory soup cocktail. The LSN and PN pathways contain different populations of mechanosensitive afferents capable of detecting a range of mechanical stimuli and individually tuned to detect the type, magnitude, and duration of the stimulus. This knowledge broadens our understanding of the potential roles these two pathways play in conveying mechanical information from the bladder to the spinal cord. PMID:18003875

  3. Effect of hypergravity on the development of vestibulocerebellar afferent fibers

    NASA Astrophysics Data System (ADS)

    Bruce, L. L.

    Gravity is a critical factor in the normal development of the vestibular system, as prolonged prenatal exposures to either micro- or hypergravity will alter the pattern of projections from specific vestibular organs to specific targets in the vestibular nuclei. This study addresses the effect of gravity on the development of vestibulocerebellar projections. In adult rats the semicircular canal afferents project mainly to the cerebellar nodulus whereas the otolith maculae project mainly to the ventral uvula of the cerebellum. To determine if the distribution pattern of these afferents is altered by exposures to altered gravity, 10 pregnant rats were exposed to hypergravity (1.5g) from embryonic day 12 (before vestibular ganglion neurons contact vestibular nuclei) to embryonic day 21 (near the time when the vestibular system becomes functional). Controls were exposed to Earth's gravity but otherwise received the same treatment. At the end of the exposure the embryos were deeply anesthetized and fixed by transcardiac perfusion with 4% paraformaldehyde in 0.1 M phosphate buffer (pH7.4). Filter strips coated with DiI and PTIR were implanted into the saccule (gravistatic vestibular receptor) or into the posterior vertical canal (angular acceleration receptor), and allowed to diffuse for 2 weeks at 37°C. Then the brains were dissected and sectioned for fluorescent confocal imaging. Examination of the control cerebella revealed that the canal and otolith afferents have reached the nodulus and uvula, and axons extend into the internal granular, Purkinje, and molecular layers. Projections from the saccule and posterior vertical canal were partially segregated into their respective domains, the uvula and nodulus. In contrast, in hypergravity-exposed rat fetuses the saccule and posterior vertical canal projections were poorly segregated, and both organs contributed labeled fibers to all layers of the nodulus and uvula. This contrasts with the increased afferent segregation

  4. Impaired intestinal afferent nerve satiety signalling and vagal afferent excitability in diet induced obesity in the mouse.

    PubMed

    Daly, Donna M; Park, Sung Jin; Valinsky, William C; Beyak, Michael J

    2011-06-01

    Gastrointestinal vagal afferents transmit satiety signals to the brain via both chemical and mechanical mechanisms. There is indirect evidence that these signals may be attenuated in obesity. We hypothesized that responses to satiety mediators and distension of the gut would be attenuated after induction of diet induced obesity. Obesity was induced by feeding a high fat diet (60% kcal from fat). Low fat fed mice (10% kcal from fat) served as a control. High fat fed mice were obese, with increased visceral fat, but were not hyperglycaemic. Recordings from jejunal afferents demonstrated attenuated responses to the satiety mediators cholecystokinin (CCK, 100 nm) and 5-hydroxytryptamine (5-HT, 10 μm), as was the response to low intensity jejunal distension, while responses to higher distension pressures were preserved. We performed whole cell patch clamp recordings on nodose ganglion neurons, both unlabelled, and those labelled by fast blue injection into the wall of the jejunum. The cell membrane of both labelled and unlabelled nodose ganglion neurons was less excitable in HFF mice, with an elevated rheobase and decreased number of action potentials at twice rheobase. Input resistance of HFF neurons was also significantly decreased. Calcium imaging experiments revealed reduced proportion of nodose ganglion neurons responding to CCK and 5-HT in obese mice. These results demonstrate a marked reduction in afferent sensitivity to satiety related stimuli after a chronic high fat diet. A major mechanism underlying this change is reduced excitability of the neuronal cell membrane. This may explain the development of hyperphagia when a high fat diet is consumed. Improving sensitivity of gastrointestinal afferent nerves may prove useful to limit food intake in obesity. PMID:21486762

  5. Amphetamine activates calcium channels through dopamine transporter-mediated depolarization.

    PubMed

    Cameron, Krasnodara N; Solis, Ernesto; Ruchala, Iwona; De Felice, Louis J; Eltit, Jose M

    2015-11-01

    Amphetamine (AMPH) and its more potent enantiomer S(+)AMPH are psychostimulants used therapeutically to treat attention deficit hyperactivity disorder and have significant abuse liability. AMPH is a dopamine transporter (DAT) substrate that inhibits dopamine (DA) uptake and is implicated in DA release. Furthermore, AMPH activates ionic currents through DAT that modify cell excitability presumably by modulating voltage-gated channel activity. Indeed, several studies suggest that monoamine transporter-induced depolarization opens voltage-gated Ca(2+) channels (CaV), which would constitute an additional AMPH mechanism of action. In this study we co-express human DAT (hDAT) with Ca(2+) channels that have decreasing sensitivity to membrane depolarization (CaV1.3, CaV1.2 or CaV2.2). Although S(+)AMPH is more potent than DA in transport-competition assays and inward-current generation, at saturating concentrations both substrates indirectly activate voltage-gated L-type Ca(2+) channels (CaV1.3 and CaV1.2) but not the N-type Ca(2+) channel (CaV2.2). Furthermore, the potency to achieve hDAT-CaV electrical coupling is dominated by the substrate affinity on hDAT, with negligible influence of L-type channel voltage sensitivity. In contrast, the maximal coupling-strength (defined as Ca(2+) signal change per unit hDAT current) is influenced by CaV voltage sensitivity, which is greater in CaV1.3- than in CaV1.2-expressing cells. Moreover, relative to DA, S(+)AMPH showed greater coupling-strength at concentrations that induced relatively small hDAT-mediated currents. Therefore S(+)AMPH is not only more potent than DA at inducing hDAT-mediated L-type Ca(2+) channel currents but is a better depolarizing agent since it produces tighter electrical coupling between hDAT-mediated depolarization and L-type Ca(2+) channel activation. PMID:26162812

  6. CATALYST EVALUATION FOR A SULFUR DIOXIDE-DEPOLARIZED ELECTROLYZER

    SciTech Connect

    Hobbs, D; Hector Colon-Mercado, H

    2007-01-31

    Thermochemical processes are being developed to provide global-scale quantities of hydrogen. A variant on sulfur-based thermochemical cycles is the Hybrid Sulfur (HyS) Process which uses a sulfur dioxide depolarized electrolyzer (SDE) to produce the hydrogen. Testing examined the activity and stability of platinum and palladium as the electrocatalyst for the SDE in sulfuric acid solutions. Cyclic and linear sweep voltammetry revealed that platinum provided better catalytic activity with much lower potentials and higher currents than palladium. Testing also showed that the catalyst activity is strongly influenced by the concentration of the sulfuric acid electrolyte.

  7. Confocal zero-angle dynamic depolarized light scattering.

    PubMed

    Potenza, M A C; Sanvito, T; Alaimo, M D; Degiorgio, V; Giglio, M

    2010-01-01

    We present a novel Dynamic Depolarized Scattering method based on a tight confocal, zero scattering angle, heterodyne scheme. The method is highly immune from parasitic multiple-scattering contributions, so that it can operate with non-index-matched samples presenting large turbidity. It provides measurements of both rotational and translational diffusion coefficients, the latter via number fluctuation spectroscopy. In addition, the amplitude ratio between the two baselines for the fast rotational mode and the slow translational mode can be used to determine the particles intrinsic birefringence. PMID:20087622

  8. Dynamic mechanical allodynia in humans is not mediated by a central presynaptic interaction of A beta-mechanoreceptive and nociceptive C-afferents.

    PubMed

    Wasner, G; Baron, R; Jänig, W

    1999-02-01

    Recently, Cervero and Laird (NeuroReport, 7 (1996) 526-528; Pain, 68 (1996) 13-23) proposed a new pathophysiological mechanism of dynamic mechanical allodynia in skin. Using the capsaicin pain model in humans, they showed that light mechanical stimulation within an area of secondary mechanical allodynia induces vasodilatation measured by laser-Doppler flowmetry. They suggested that the low-threshold A beta-mechanoreceptive fibres depolarize the central terminals of nociceptive primary afferent neurons via interneurons. Consequently, the vasodilatation is produced by impulses conducted antidromically in nociceptive C-axons. The allodynia was proposed to result from depolarization of central terminals of primary afferent neurons with C-fibres with activation of nociceptive dorsal horn neurons. In order to extend these findings, we used the same experimental approach but additionally stimulated the A beta-fibres electrically to evoke secondary allodynia during simultaneous monitoring skin blood flow. Twenty microlitres of a 0.5% capsaicin solution was injected intradermally into the dorsal forearm. Skin sites that demonstrated dynamic mechanical allodynia but were not located within the area of primary hyperalgesia and flare were investigated. Ten mm away from a laser-Doppler probe, dynamic mechanical allodynia was induced for 1 min (1) by moving a cotton swab and (2) by electrically stimulating the afferent nerve endings transdermally. Increasing stimulus intensities were applied (0.3-4 mA, 40 Hz, pulse duration 0.2 ms). After intracutaneous injection of capsaicin, light mechanical stimulation elicited a burning painful sensation (numeric analogue scale (NAS) 1.5-3) and concomitant movement artefacts at the laser signal. Antidromic vasodilatation was never observed. In this area of dynamic allodynia, electrical stimulation at stimulus intensities that were not painful before capsaicin injection (A beta-stimulation) was now able to elicit a burning painful sensation

  9. Pad B Liquid Hydrogen Storage Tank

    NASA Technical Reports Server (NTRS)

    Hall, Felicia

    2007-01-01

    Kennedy Space Center is home to two liquid hydrogen storage tanks, one at each launch pad of Launch Complex 39. The liquid hydrogen storage tank at Launch Pad B has a significantly higher boil off rate that the liquid hydrogen storage tank at Launch Pad A. This research looks at various calculations concerning the at Launch Pad B in an attempt to develop a solution to the excess boil off rate. We will look at Perlite levels inside the tank, Boil off rates, conductive heat transfer, and radiant heat transfer through the tank. As a conclusion to the research, we will model the effects of placing an external insulation to the tank in order to reduce the boil off rate and increase the economic efficiency of the liquid hydrogen storage tanks.

  10. Blue Origin Conducts Pad Escape Test

    NASA Video Gallery

    Blue Origin conducted a successful pad escape test Oct. 19 at the company's West Texas launch site, firing its pusher escape motor and launching a full-scale suborbital crew capsule from a simulate...

  11. Traumatic herniation of the buccal fat pad.

    PubMed

    Iehara, Tomoko; Tomoyasu, Chihiro; Nakajima, Hisakazu; Osamura, Toshio; Hosoi, Hajime

    2016-07-01

    Traumatic herniation of the buccal fat pad is a rare traumatic disease. Treatment consists of either excision or replacement. We herein report the first case in which a traumatic herniation of the buccal fat pad healed naturally. It was necessary to differentiate the disease from lipoblastoma. A 17-month-old boy was admitted to a clinic with an intraoral tumor that had suddenly increased in size. The tumor was diagnosed as herniation of the buccal fat pad on pathology of a biopsy specimen. In the present case, the escaped buccal fat body returned naturally and engrafted without dysfunction or facial defects. Given that young children may easily fall down with various objects in their mouth, care is required to prevent traumatic accidents. Traumatic herniation of the buccal fat pad should be considered in the differentiation of tumors of the oral cavity in young children. PMID:26892590

  12. Alining Solder Pads on a Solar Cell

    NASA Technical Reports Server (NTRS)

    Lazzery, A. G.

    1984-01-01

    Mechanism consisting of stylus and hand-operated lever incorporated into screening machine to precisely register front and back solder pads during solar-cell assembly. Technique may interest those assembling solar cells manually for research or prototype work.

  13. The Road to Pad Abort 1

    NASA Video Gallery

    At the White Sands Missile Range in Las Cruces, N.M., engineers and technicians are preparing for the Pad Abort 1 flight test. The Launch Abort System is a sophisticated new rocket tower designed t...

  14. Soyuz Rolled to Launch Pad in Kazakhstan

    NASA Video Gallery

    The Soyuz rocket is rolled out to the launch pad by train on Tuesday, March 26, 2013, at the Baikonur Cosmodrome in Kazakhstan. Launch of the Soyuz rocket is scheduled for March 29 and will send Ex...

  15. Expedition 30 Soyuz Moves to Launch Pad

    NASA Video Gallery

    On Dec. 19, the Soyuz TMA-03M spacecraft and its booster were moved to the launch pad at the Baikonur Cosmodrome in Kazakhstan for final preparations before launch to the International Space Statio...

  16. Knuckle pads – a rare finding

    PubMed Central

    Gengenbacher, Michael; Bianchi, Stefano

    2012-01-01

    Knuckle pads are rare harmless subcutaneous nodules that must be differentiated from joint disease of the proximal interphalangeal or rarely of the metacarpophalangeal joints as well as from other masses of the paraarticular tissues. We present a case of an otherwise healthy 36-year-old woman presenting with bilateral knuckle pads located at the dorsal aspect of the proximal interphalangeal joints. No predisposition to a specific musculoskeletal disorder was noted. Ultrasound revealed well-delimited subcutaneous hypoechoic masses without internal flow signals at color Doppler. Histology showed proliferation of myofibroblasts with a decrease of elastic filaments in the deep dermis. The clinical picture, the family history in addition to the histology allowed us to make the diagnosis of knuckle pads. We present the ultrasound findings of knuckle pads and discuss the differential diagnosis of a “swelling” in the dorsal region of proximal interphalangeal joints and metacarpophalangeal joints. PMID:26672439

  17. Gel pad application for automated breast sonography.

    PubMed

    Kim, Yun Ju; Kim, Sung Hun; Jeh, Su Kyung; Choi, Jae Jeong; Kang, Bong Joo; Song, Byung Joo

    2015-04-01

    The purpose of this study was to describe the technical aspects of gel pad application for automated breast sonography and to show its effects on pain relief, scan coverage, and image quality. Twenty patients underwent 2 sets of automated breast sonography with and without gel pad application and were then asked to provide feedback on the examination-related pain. Scan coverage and image quality were compared quantitatively and qualitatively. The degree of pain was significantly decreased after gel pad application (P < .0001). The scan coverage was expanded particularly at the mid-portion of the breast. Image quality was satisfactory without significant differences between the sets. Gel pad application for automated breast sonography is easy and provides significant pain relief. The scan coverage was expanded, while the image quality was maintained. PMID:25792588

  18. Differential roles of stretch-sensitive pelvic nerve afferents innervating mouse distal colon and rectum

    PubMed Central

    Brumovsky, Pablo R.; Gebhart, Gerald F.

    2010-01-01

    Information about colorectal distension (i.e., colorectal dilation by increased intraluminal pressure) is primarily encoded by stretch-sensitive colorectal afferents in the pelvic nerve (PN). Despite anatomic differences between rectum and distal colon, little is known about the functional roles of colonic vs. rectal afferents in the PN pathway or the quantitative nature of mechanosensory encoding. We utilized an in vitro mouse colorectum-PN preparation to investigate pressure-encoding characteristics of colorectal afferents. The colorectum with PN attached was dissected, opened longitudinally, and pinned flat in a Sylgard-lined chamber. Action potentials of afferent fibers evoked by circumferential stretch (servo-controlled force actuator) were recorded from the PN. Stretch-sensitive fibers were categorized into the following four groups: colonic muscular, colonic muscular/mucosal, rectal muscular, and rectal muscular/mucosal. Seventy-nine stretch-sensitive PN afferents evenly distributed into the above four groups were studied. Rectal muscular afferents had significantly greater stretch-responses than the other three groups. Virtually all rectal afferents (98%) had low thresholds for response and encoded stimulus intensity into the noxious range without obvious saturation. Most colonic afferents (72%) also had low thresholds (<14 mmHg), but a significant proportion (28%) had high thresholds (>18 mmHg) for response. These high-threshold colonic afferents were sensitized to stretch by inflammatory soup; response threshold was significantly reduced (from 23 to 12 mmHg), and response magnitude significantly increased. These results suggest that the encoding of mechanosensory information differs between colonic and rectal stretch-sensitive PN afferents. Rectal afferents have a wide response range to stretch, whereas high-threshold colonic afferents likely contribute to visceral nociception. PMID:20075141

  19. IT Does Not Love iPads

    ERIC Educational Resources Information Center

    Fredette, Michelle

    2013-01-01

    On many campuses, iPads have taken over the hearts and minds of everyone. Everyone, that is, except the IT department. These sexy tablets might be the apple of faculty and students' eyes, but for IT directors and their staffs, working with iPads in an enterprise network environment is not the stuff of a love affair. To state the problem…

  20. Enter the iPad (or Not?)

    ERIC Educational Resources Information Center

    Waters, John K.

    2010-01-01

    Few computing devices have sparked the burning gizmo lust ignited by the iPad. Apple's latest entry into the tablet PC market didn't generate much heat when it was first unveiled in January, but by April 3, the day of the official release, feverish customers were mobbing Apple stores. The company claims to have sold 300,000 iPads by midnight on…

  1. Corneal afferents differentially target thalamic- and parabrachial-projecting neurons in trigeminal subnucleus caudalis

    PubMed Central

    Aicher, Sue A.; Hermes, Sam M.; Hegarty, Deborah M.

    2012-01-01

    Dorsal horn neurons send ascending projections to both thalamic nuclei and parabrachial nuclei; these pathways are thought to be critical pathways for central processing of nociceptive information. Afferents from the corneal surface of the eye mediate nociception from this tissue which is susceptible to clinically important pain syndromes. This study examined corneal afferents to the trigeminal dorsal horn and compared inputs to thalamic- and parabrachial-projecting neurons. We used anterograde tracing with cholera toxin B subunit to identify corneal afferent projections to trigeminal dorsal horn, and the retrograde tracer FluoroGold to identify projection neurons. Studies were conducted in adult male Sprague-Dawley rats. Our analysis was conducted at two distinct levels of the trigeminal subnucleus caudalis (Vc) which receive corneal afferent projections. We found that corneal afferents project more densely to the rostral pole of Vc than the caudal pole. We also quantified the number of thalamic- and parabrachial-projecting neurons in the regions of Vc that receive corneal afferents. Corneal afferent inputs to both groups of projection neurons were also more abundant in the rostral pole of Vc. Finally, by comparing the frequency of corneal afferent appositions to thalamic- versus parabrachial-projecting neurons, we found that corneal afferents preferentially target parabrachial-projecting neurons in trigeminal dorsal horn. These results suggest that nociceptive pain from the cornea may be primarily mediated by a non-thalamic ascending pathway. PMID:23201828

  2. Long-term sensitization of mechanosensitive and -insensitive afferents in mice with persistent colorectal hypersensitivity

    PubMed Central

    La, Jun-ho; Schwartz, Erica S.; Tanaka, Takahiro; McMurray, Timothy P.; Gebhart, G. F.

    2012-01-01

    Afferent input contributes significantly to the pain and colorectal hypersensitivity that characterize irritable bowel syndrome. In the present study, we investigated the contributions of mechanically sensitive and mechanically insensitive afferents (MIAs; or silent afferents) to colorectal hypersensitivity. The visceromotor response to colorectal distension (CRD; 15–60 mmHg) was recorded in mice before and for weeks after intracolonic treatment with zymosan or saline. After CRD tests, the distal colorectum with the pelvic nerve attached was removed for single-fiber electrophysiological recordings. Colorectal afferent endings were located by electrical stimulation and characterized as mechanosensitive or not by blunt probing, mucosal stroking, and circumferential stretch. Intracolonic zymosan produced persistent colorectal hypersensitivity (>24 days) associated with brief colorectal inflammation. Pelvic nerve muscular-mucosal but not muscular mechanosensitive afferents recorded from mice with colorectal hypersensitivity exhibited persistent sensitization. In addition, the proportion of MIAs (relative to control) was significantly reduced from 27% to 13%, whereas the proportion of serosal afferents was significantly increased from 34% to 53%, suggesting that MIAs acquired mechanosensitivity. PGP9.5 immunostaining revealed no significant loss of colorectal nerve fiber density, suggesting that the reduction in MIAs is not due to peripheral fiber loss after intracolonic zymosan. These results indicate that colorectal MIAs and sensitized muscular-mucosal afferents that respond to stretch contribute significantly to the afferent input that sustains hypersensitivity to CRD, suggesting that targeted management of colorectal afferent input could significantly reduce patients' complaints of pain and hypersensitivity. PMID:22268098

  3. 21 CFR 884.5435 - Unscented menstrual pad.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Unscented menstrual pad. 884.5435 Section 884.5435... § 884.5435 Unscented menstrual pad. (a) Identification. An unscented menstrual pad is a device that is a pad made of cellulosic or synthetic material which is used to absorb menstrual or other...

  4. Partially coherent electromagnetic beams propagating through double-wedge depolarizers

    NASA Astrophysics Data System (ADS)

    de Sande, J. Carlos G.; Piquero, Gemma; Santarsiero, Massimo; Gori, Franco

    2014-03-01

    The irradiance and polarization characteristics of quasi-monochromatic partially coherent electromagnetic beams are analyzed when they propagate after passing through a deterministic linear optical element, i.e., an optical element that can be represented by a Jones matrix. A class of such optical elements, which includes double-wedge depolarizers and polarization gratings, is defined and studied in detail. Analytical expressions are obtained for the case of double-wedge depolarizers and examples are given for an incident Gaussian Schell-model beam. For such an input beam, the effects on the irradiance and degree of polarization of the field propagating beyond the optical element are investigated in detail. A rich variety of behaviors is obtained by varying the beam size, coherence width and polarization state of the input field. The results not only provide a mathematical extension of well-known results to the domain of partial coherence, but they also exemplify mixing between coherence and polarization, which is, of course, not possible if, for example, fully spatially coherent fields are analyzed.

  5. Widespread depolarization during expiration: a source of respiratory drive?

    PubMed

    Jerath, Ravinder; Crawford, Molly W; Barnes, Vernon A; Harden, Kyler

    2015-01-01

    Respiration influences various pacemakers and rhythms of the body during inspiration and expiration but the underlying mechanisms are relatively unknown. Understanding this phenomenon is important, as breathing disorders, breath holding, and hyperventilation can lead to significant medical conditions. We discuss the physiological modulation of heart rhythm, blood pressure, sympathetic nerve activity, EEG, and other changes observed during inspiration and expiration. We also correlate the intracellular mitochondrial respiratory metabolic processes with real-time breathing and correlate membrane potential changes with inspiration and expiration. We propose that widespread minor hyperpolarization occurs during inspiration and widespread minor depolarization occurs during expiration. This depolarization is likely a source of respiratory drive. Further knowledge of intracellular and extracellular ionic changes associated with respiration will enhance ourunderstanding of respiration and its role as a modulator of cellular membrane potential. This could expand treatment options for a wide range of health conditions, such as breathing disorders, stress-related disorders, and further our understanding of the Hering-Breuer reflex and respiratory sinus arrhythmia. PMID:25434482

  6. Spreading Depression, Spreading Depolarizations, and the Cerebral Vasculature

    PubMed Central

    Ayata, Cenk; Lauritzen, Martin

    2015-01-01

    Spreading depression (SD) is a transient wave of near-complete neuronal and glial depolarization associated with massive transmembrane ionic and water shifts. It is evolutionarily conserved in the central nervous systems of a wide variety of species from locust to human. The depolarization spreads slowly at a rate of only millimeters per minute by way of grey matter contiguity, irrespective of functional or vascular divisions, and lasts up to a minute in otherwise normal tissue. As such, SD is a radically different breed of electrophysiological activity compared with everyday neural activity, such as action potentials and synaptic transmission. Seventy years after its discovery by Leão, the mechanisms of SD and its profound metabolic and hemodynamic effects are still debated. What we did learn of consequence, however, is that SD plays a central role in the pathophysiology of a number of diseases including migraine, ischemic stroke, intracranial hemorrhage, and traumatic brain injury. An intriguing overlap among them is that they are all neurovascular disorders. Therefore, the interplay between neurons and vascular elements is critical for our understanding of the impact of this homeostatic breakdown in patients. The challenges of translating experimental data into human pathophysiology notwithstanding, this review provides a detailed account of bidirectional interactions between brain parenchyma and the cerebral vasculature during SD and puts this in the context of neurovascular diseases. PMID:26133935

  7. Depolarization Lidar Determination Of Cloud-Base Microphysical Properties

    NASA Astrophysics Data System (ADS)

    Donovan, D. P.; Klein Baltink, H.; Henzing, J. S.; de Roode, S.; Siebesma, A. P.

    2016-06-01

    The links between multiple-scattering induced depolarization and cloud microphysical properties (e.g. cloud particle number density, effective radius, water content) have long been recognised. Previous efforts to use depolarization information in a quantitative manner to retrieve cloud microphysical cloud properties have also been undertaken but with limited scope and, arguably, success. In this work we present a retrieval procedure applicable to liquid stratus clouds with (quasi-)linear LWC profiles and (quasi-)constant number density profiles in the cloud-base region. This set of assumptions allows us to employ a fast and robust inversion procedure based on a lookup-table approach applied to extensive lidar Monte-Carlo multiple-scattering calculations. An example validation case is presented where the results of the inversion procedure are compared with simultaneous cloud radar observations. In non-drizzling conditions it was found, in general, that the lidar- only inversion results can be used to predict the radar reflectivity within the radar calibration uncertainty (2-3 dBZ). Results of a comparison between ground-based aerosol number concentration and lidar-derived cloud base number considerations are also presented. The observed relationship between the two quantities is seen to be consistent with the results of previous studies based on aircraft-based in situ measurements.

  8. Kv1 channels and neural processing in vestibular calyx afferents.

    PubMed

    Meredith, Frances L; Kirk, Matthew E; Rennie, Katherine J

    2015-01-01

    Potassium-selective ion channels are important for accurate transmission of signals from auditory and vestibular sensory end organs to their targets in the central nervous system. During different gravity conditions, astronauts experience altered input signals from the peripheral vestibular system resulting in sensorimotor dysfunction. Adaptation to altered sensory input occurs, but it is not explicitly known whether this involves synaptic modifications within the vestibular epithelia. Future investigations of such potential plasticity require a better understanding of the electrophysiological mechanisms underlying the known heterogeneity of afferent discharge under normal conditions. This study advances this understanding by examining the role of the Kv1 potassium channel family in mediating action potentials in specialized vestibular afferent calyx endings in the gerbil crista and utricle. Pharmacological agents selective for different sub-types of Kv1 channels were tested on membrane responses in whole cell recordings in the crista. Kv1 channels sensitive to α-dendrotoxin and dendrotoxin-K were found to prevail in the central regions, whereas K(+) channels sensitive to margatoxin, which blocks Kv1.3 and 1.6 channels, were more prominent in peripheral regions. Margatoxin-sensitive currents showed voltage-dependent inactivation. Dendrotoxin-sensitive currents showed no inactivation and dampened excitability in calyces in central neuroepithelial regions. The differential distribution of Kv1 potassium channels in vestibular afferents supports their importance in accurately relaying gravitational and head movement signals through specialized lines to the central nervous system. Pharmacological modulation of specific groups of K(+) channels could help alleviate vestibular dysfunction on earth and in space. PMID:26082693

  9. Kv1 channels and neural processing in vestibular calyx afferents

    PubMed Central

    Meredith, Frances L.; Kirk, Matthew E.; Rennie, Katherine J.

    2015-01-01

    Potassium-selective ion channels are important for accurate transmission of signals from auditory and vestibular sensory end organs to their targets in the central nervous system. During different gravity conditions, astronauts experience altered input signals from the peripheral vestibular system resulting in sensorimotor dysfunction. Adaptation to altered sensory input occurs, but it is not explicitly known whether this involves synaptic modifications within the vestibular epithelia. Future investigations of such potential plasticity require a better understanding of the electrophysiological mechanisms underlying the known heterogeneity of afferent discharge under normal conditions. This study advances this understanding by examining the role of the Kv1 potassium channel family in mediating action potentials in specialized vestibular afferent calyx endings in the gerbil crista and utricle. Pharmacological agents selective for different sub-types of Kv1 channels were tested on membrane responses in whole cell recordings in the crista. Kv1 channels sensitive to α-dendrotoxin and dendrotoxin-K were found to prevail in the central regions, whereas K+ channels sensitive to margatoxin, which blocks Kv1.3 and 1.6 channels, were more prominent in peripheral regions. Margatoxin-sensitive currents showed voltage-dependent inactivation. Dendrotoxin-sensitive currents showed no inactivation and dampened excitability in calyces in central neuroepithelial regions. The differential distribution of Kv1 potassium channels in vestibular afferents supports their importance in accurately relaying gravitational and head movement signals through specialized lines to the central nervous system. Pharmacological modulation of specific groups of K+ channels could help alleviate vestibular dysfunction on earth and in space. PMID:26082693

  10. Heat pulse excitability of vestibular hair cells and afferent neurons.

    PubMed

    Rabbitt, Richard D; Brichta, Alan M; Tabatabaee, Hessam; Boutros, Peter J; Ahn, JoongHo; Della Santina, Charles C; Poppi, Lauren A; Lim, Rebecca

    2016-08-01

    In the present study we combined electrophysiology with optical heat pulse stimuli to examine thermodynamics of membrane electrical excitability in mammalian vestibular hair cells and afferent neurons. We recorded whole cell currents in mammalian type II vestibular hair cells using an excised preparation (mouse) and action potentials (APs) in afferent neurons in vivo (chinchilla) in response to optical heat pulses applied to the crista (ΔT ≈ 0.25°C per pulse). Afferent spike trains evoked by heat pulse stimuli were diverse and included asynchronous inhibition, asynchronous excitation, and/or phase-locked APs synchronized to each infrared heat pulse. Thermal responses of membrane currents responsible for APs in ganglion neurons were strictly excitatory, with Q10 ≈ 2. In contrast, hair cells responded with a mix of excitatory and inhibitory currents. Excitatory hair cell membrane currents included a thermoelectric capacitive current proportional to the rate of temperature rise (dT/dt) and an inward conduction current driven by ΔT An iberiotoxin-sensitive inhibitory conduction current was also evoked by ΔT, rising in <3 ms and decaying with a time constant of ∼24 ms. The inhibitory component dominated whole cell currents in 50% of hair cells at -68 mV and in 67% of hair cells at -60 mV. Responses were quantified and described on the basis of first principles of thermodynamics. Results identify key molecular targets underlying heat pulse excitability in vestibular sensory organs and provide quantitative methods for rational application of optical heat pulses to examine protein biophysics and manipulate cellular excitability. PMID:27226448

  11. Mechano- and thermosensitivity of regenerating cutaneous afferent nerve fibers.

    PubMed

    Jänig, Wilfrid; Grossmann, Lydia; Gorodetskaya, Natalia

    2009-06-01

    Crush lesion of a skin nerve is followed by sprouting of myelinated (A) and unmyelinated (C) afferent fibers into the distal nerve stump. Here, we investigate quantitatively both ongoing activity and activity evoked by mechanical or thermal stimulation of the nerve in 43 A- and 135 C-fibers after crush lesion of the sural nerve using neurophysiological recordings in anesthetized rats. The discharge patterns in the injured afferent nerve fibers and in intact (control) afferent nerve fibers were compared. (1) Almost all (98%) A-fibers were mechanosensitive, some of them exhibited additionally weak cold/heat sensitivity; 7% had ongoing activity. (2) Three patterns of physiologically evoked activity were present in the lesioned C-fibers: (a) C-fibers with type 1 cold sensitivity (low cold threshold, inhibition on heating, high level of ongoing and cold-evoked activity; 23%): almost all of them were mechanoinsensitive and 40% of them were additionally heat-sensitive; (b) C-fibers with type 2 cold sensitivity (high cold threshold, low level of ongoing and cold-evoked activity; 23%). All of them were excited by mechanical and/or heat stimuli; (c) cold-insensitive C-fibers (54%), which were heat- and/or mechanosensitive. (3) The proportions of C-fibers exhibiting these three patterns of discharge to physiological stimuli were almost identical in the population of injured C-fibers and in a population of 91 intact cutaneous C-fibers. 4. Ongoing activity was present in 56% of the lesioned C-fibers. Incidence and rate of ongoing activity were the same in the populations of lesioned and intact type 1 cold-sensitive C-fibers. The incidence (but not rate) of ongoing activity was significantly higher in lesioned type 2 cold-sensitive and cold insensitive C-fibers than in the corresponding populations of intact C-fibers (42/93 fibers vs. 11/72 fibers). PMID:19139872

  12. Bladder afferent hyperexcitability in bladder pain syndrome/interstitial cystitis

    PubMed Central

    Yoshimura, Naoki; Oguchi, Tomohiko; Yokoyama, Hitoshi; Funahashi, Yasuhito; Yoshikawa, Satoru; Sugino, Yoshio; Kawamorita, Naoki; Kashyap, Mahendra P; Chancellor, Michael B; Tyagi, Pradeep; Ogawa, Teruyuki

    2014-01-01

    Bladder pain syndrome/interstitial cystitis is a disease with lower urinary tract symptoms, such as bladder pain and urinary frequency, which results in seriously impaired quality of life of patients. The extreme pain and urinary frequency are often difficult to treat. Although the etiology of bladder pain syndrome/interstitial cystitis is still not known, there is increasing evidence showing that afferent hyperexcitability as a result of neurogenic bladder inflammation and urothelial dysfunction is important to the pathophysiological basis of symptom development. Further investigation of the pathophysiology will lead to the effective treatment of patients with bladder pain syndrome/interstitial cystitis. PMID:24807488

  13. Characterization of natural and irradiated nails by means of the depolarization metrics

    NASA Astrophysics Data System (ADS)

    Savenkov, Sergey; Priezzhev, Alexander; Oberemok, Yevgen; Sholom, Sergey; Kolomiets, Ivan; Chunikhina, Kateryna

    2016-07-01

    Mueller polarimetry is applied to study the samples of nails: natural (or reference) and irradiated to 2 Gy ionizing radiation dose. We measure the whole Mueller matrices of the samples as a function of the scattering angle at a wavelength of 632.8 nm. We apply depolarization analysis to measured Mueller matrices by calculating the depolarization metrics [depolarization index, Q(M)-metric, first and second Lorenz indices, Cloude and Lorenz entropy] to quantify separability of the different samples of nails under study based on differences in their Mueller matrix. The results show that nail samples strongly depolarize the output light in backscattering, and irradiation in all cases results in increasing of depolarization. Most sensitive among depolarization metrics are the Lorenz entropy and Q(M)-metric.

  14. Characterization of natural and irradiated nails by means of the depolarization metrics.

    PubMed

    Savenkov, Sergey; Priezzhev, Alexander; Oberemok, Yevgen; Sholom, Sergey; Kolomiets, Ivan; Chunikhina, Kateryna

    2016-07-01

    Mueller polarimetry is applied to study the samples of nails: natural (or reference) and irradiated to 2 Gy ionizing radiation dose. We measure the whole Mueller matrices of the samples as a function of the scattering angle at a wavelength of 632.8 nm. We apply depolarization analysis to measured Mueller matrices by calculating the depolarization metrics [depolarization index, Q(M)-metric, first and second Lorenz indices, Cloude and Lorenz entropy] to quantify separability of the different samples of nails under study based on differences in their Mueller matrix. The results show that nail samples strongly depolarize the output light in backscattering, and irradiation in all cases results in increasing of depolarization. Most sensitive among depolarization metrics are the Lorenz entropy and Q(M)-metric. PMID:26927390

  15. A depolarization and attenuation experiment using the CTS satellite. Volume 1: Experiment description

    NASA Technical Reports Server (NTRS)

    Bostian, C. W.; Holt, S. B., Jr.; Kauffman, S. R.; Manus, E. A.; Marshall, R. E.; Stutzman, W. L.; Wiley, P. H.

    1976-01-01

    An experiment for measuring precipitation attenuation and depolarization on the Communications Technology Satellite (CTS) 11.7 GHz downlink is described. Attenuation and depolarization of the signal received from the spacecraft is monitored on a 24 hour basis. Data is correlated with ground weather conditions. Theoretical models for millimeter wave propagation through rain are refined for maximum agreement with observed data. Techniques are developed for predicting and mimimizing the effects of rain scatter and depolarization on future satellite communication systems.

  16. Peripheral innervation patterns of vestibular nerve afferents in the bullfrog utriculus

    NASA Technical Reports Server (NTRS)

    Baird, Richard A.; Schuff, N. R.

    1994-01-01

    Vestibular nerve afferents innervating the bullfrog utriculus differ in their response dynamics and sensitivity to natural stimulation. They also supply hair cells that differ markedly in hair bundle morphology. To examine the peripheral innervation patterns of individual utricular afferents more closely, afferent fibers were labeled by the extracellular injection of horseradish peroxidase (HRP) into the vestibular nerve after sectioning the vestibular nerve medial to Scarpa's ganglion to allow the degeneration of sympathetic and efferent fibers. The peripheral arborizations of individual afferents were then correlated with the diameters of their parent axons, the regions of the macula they innervate, and the number and type of hair cells they supply. The utriculus is divided by the striola, a narrow zone of distinctive morphology, into media and lateral parts. Utiricular afferents were classified as striolar or extrastriolar according to the epithelial entrance of their parent axons and the location of their terminal fields. In general, striolar afferents had thicker parent axons, fewer subepithelial bifurcations, larger terminal fields, and more synaptic endings than afferents in extrstriolar regions. Afferents in a juxtastriolar zone, immediately adjacent to the medial striola, had innervation patterns transitional between those in the striola and more peripheral parts of the medial extrastriola. moast afferents innervated only a single macular zone. The terminal fields of striolar afferents, with the notable exception of a few afferents with thin parent axons, were generally confined to one side of the striola. Hair cells in the bullfrog utriculus have perviously been classified into four types based on hair bundle morphology. Afferents in the extrastriolar and juxtastriolar zones largely or exclusively innervated Type B hair cells, the predominant hair cell type in the utricular macula. Striolar afferents supplied a mixture of four hair cell types, but largely

  17. Directional sensitivity of human periodontal mechanoreceptive afferents to forces applied to the teeth.

    PubMed Central

    Trulsson, M; Johansson, R S; Olsson, K A

    1992-01-01

    1. Single-unit impulse activity from thirty-eight mechanoreceptive afferent fibres was recorded in the human inferior alveolar nerve using tungsten microelectrodes. All afferents responded to mechanical stimulation of the teeth and most likely supplied periodontal mechanoreceptors. 2. All afferents showed their highest sensitivity to forces applied to a particular tooth (the lower incisors, the canine or the first premolar). Forces with 'ramp-and-hold' shaped profiles of similar magnitudes were applied to that tooth in the following six directions: lingual, labial, mesial and distal in the horizontal plane, and up and down in the axial direction of the tooth. Both static and dynamic response components were analysed. 3. All afferents were 'slowly adapting' since they discharged continuously in response to static forces in at least one stimulation direction. Twenty-five afferents (66%) were spontaneously active in the sense that they showed an on-going discharge in the absence of external stimulation. 4. Diverse receptive fields were observed. Most afferents (74%) responded to static forces in two or three of the four horizontal directions. Likewise, all units showed excitatory responses to axial loading with a majority (74%) responding in one of the two axial directions and the remainder in both axial directions. Spontaneously active afferents generally decreased their discharge rate when stimulated in directions opposite to the directions exciting the afferent. With regard to population responses, approximately half of the afferents showed excitatory responses to each stimulus direction except for downwards, in which 86% responded. 5. Twenty-three afferents (61%) exhibited the strongest response to forces in one of the horizontal directions. Of those, a majority were most responsive to the lingual direction (52%) and some to the labial direction (30%). Accordingly, the discharge rates during force application averaged over the whole afferent sample were highest in

  18. [Intramural chronotopography of depolarization of myocardium of heart ventricles of pig (Sus scrofa domesticus)].

    PubMed

    2014-01-01

    Sequence of depolarization of myocardium of pig heart ventricles was studied by the method of multichannel synchronous cardioelectrotopography. There is established formation of areas of early depolarization in subendocardium of interventricular septum and in the base of left ventricle papillary muscles; of multiple foci--in the depth of walls; of areas of late depolarization--in subepicardium of the left ventricle dorsolateral side. As compared with other species of ungulate animals (reindeer and sheep, in pig heart ventricles, differences are revealed in locations of early and late depolarization, a breakdown of the excitation wave into subepicardium. PMID:25508945

  19. [Intramural chronotopography of depolarization of myocardium of heart ventricles of pig (Sus scrofa domesticus)].

    PubMed

    Gulyaeva, A S; Roshchecskaya, I M; Roshchevsky, M P

    2014-01-01

    Sequence of depolarization of myocardium of pig heart ventricles was studied by the method of multichannel synchronous cardioelectrotopography. There is established formation of areas of early depolarization in subendocardium of interventricular septum and in the base of left ventricle papillary muscles; of multiple foci--in the depth of walls; of areas of late depolarization--in subepicardium of the left ventricle dorsolateral side. As compared with other species of ungulate animals (reindeer and sheep, in pig heart ventricles, differences are revealed in locations of early and late depolarization, a breakdown of the excitation wave into subepicardium. PMID:25486814

  20. Plasmacytoid dendritic cells migrate in afferent skin lymph.

    PubMed

    Pascale, Florentina; Pascale, Florentia; Contreras, Vanessa; Bonneau, Michel; Courbet, Alexandre; Chilmonczyk, Stefan; Bevilacqua, Claudia; Epardaud, Mathieu; Eparaud, Mathieu; Niborski, Violeta; Riffault, Sabine; Balazuc, Anne-Marie; Foulon, Eliane; Guzylack-Piriou, Laurence; Riteau, Beatrice; Hope, Jayne; Bertho, Nicolas; Charley, Bernard; Schwartz-Cornil, Isabelle

    2008-05-01

    Conventional dendritic cells enter lymph nodes by migrating from peripheral tissues via the lymphatic route, whereas plasmacytoid dendritic cells (pDC), also called IFN-producing cells (IPC), are described to gain nodes from blood via the high endothelial venules. We demonstrate here that IPC/pDC migrate in the afferent lymph of two large mammals. In sheep, injection of type A CpG oligodinucleotide (ODN) induced lymph cells to produce type I IFN. Furthermore, low-density lymph cells collected at steady state produced type I IFN after stimulation with type A CpG ODN and enveloped viruses. Sheep lymph IPC were found within a minor B(neg)CD11c(neg) subset expressing CD45RB. They presented a plasmacytoid morphology, expressed high levels of TLR-7, TLR-9, and IFN regulatory factor 7 mRNA, induced IFN-gamma production in allogeneic CD4(pos) T cells, and differentiated into dendritic cell-like cells under viral stimulation, thus fulfilling criteria of bona fide pDC. In mini-pig, a CD4(pos)SIRP(pos) subset in afferent lymph cells, corresponding to pDC homologs, produced type I IFN after type A CpG-ODN triggering. Thus, pDC can link innate and acquired immunity by migrating from tissue to draining node via lymph, similarly to conventional dendritic cells. PMID:18424716

  1. Interactions between visceral afferent signaling and stimulus processing

    PubMed Central

    Critchley, Hugo D.; Garfinkel, Sarah N.

    2015-01-01

    Visceral afferent signals to the brain influence thoughts, feelings and behavior. Here we highlight the findings of a set of empirical investigations in humans concerning body-mind interaction that focus on how feedback from states of autonomic arousal shapes cognition and emotion. There is a longstanding debate regarding the contribution of the body to mental processes. Recent theoretical models broadly acknowledge the role of (autonomically-mediated) physiological arousal to emotional, social and motivational behaviors, yet the underlying mechanisms are only partially characterized. Neuroimaging is overcoming this shortfall; first, by demonstrating correlations between autonomic change and discrete patterns of evoked, and task-independent, neural activity; second, by mapping the central consequences of clinical perturbations in autonomic response and; third, by probing how dynamic fluctuations in peripheral autonomic state are integrated with perceptual, cognitive and emotional processes. Building on the notion that an important source of the brain's representation of physiological arousal is derived from afferent information from arterial baroreceptors, we have exploited the phasic nature of these signals to show their differential contribution to the processing of emotionally-salient stimuli. This recent work highlights the facilitation at neural and behavioral levels of fear and threat processing that contrasts with the more established observations of the inhibition of central pain processing during baroreceptors activation. The implications of this body-brain-mind axis are discussed. PMID:26379481

  2. Cross-Modal Calibration of Vestibular Afference for Human Balance

    PubMed Central

    Héroux, Martin E; Law, Tammy C. Y.; Fitzpatrick, Richard C.; Blouin, Jean-Sébastien

    2015-01-01

    To determine how the vestibular sense controls balance, we used instantaneous head angular velocity to drive a galvanic vestibular stimulus so that afference would signal that head movement was faster or slower than actual. In effect, this changed vestibular afferent gain. This increased sway 4-fold when subjects (N = 8) stood without vision. However, after a 240 s conditioning period with stable balance achieved through reliable visual or somatosensory cues, sway returned to normal. An equivalent galvanic stimulus unrelated to sway (not driven by head motion) was equally destabilising but in this situation the conditioning period of stable balance did not reduce sway. Reflex muscle responses evoked by an independent, higher bandwidth vestibular stimulus were initially reduced in amplitude by the galvanic stimulus but returned to normal levels after the conditioning period, contrary to predictions that they would decrease after adaptation to increased sensory gain and increase after adaptation to decreased sensory gain. We conclude that an erroneous vestibular signal of head motion during standing has profound effects on balance control. If it is unrelated to current head motion, the CNS has no immediate mechanism of ignoring the vestibular signal to reduce its influence on destabilising balance. This result is inconsistent with sensory reweighting based on disturbances. The increase in sway with increased sensory gain is also inconsistent with a simple feedback model of vestibular reflex action. Thus, we propose that recalibration of a forward sensory model best explains the reinterpretation of an altered reafferent signal of head motion during stable balance. PMID:25894558

  3. Microsecond-Scale Timing Precision in Rodent Trigeminal Primary Afferents

    PubMed Central

    Bale, Michael R.; Campagner, Dario; Erskine, Andrew

    2015-01-01

    Communication in the nervous system occurs by spikes: the timing precision with which spikes are fired is a fundamental limit on neural information processing. In sensory systems, spike-timing precision is constrained by first-order neurons. We found that spike-timing precision of trigeminal primary afferents in rats and mice is limited both by stimulus speed and by electrophysiological sampling rate. High-speed video of behaving mice revealed whisker velocities of at least 17,000°/s, so we delivered an ultrafast “ping” (>50,000°/s) to single whiskers and sampled primary afferent activity at 500 kHz. Median spike jitter was 17.4 μs; 29% of neurons had spike jitter < 10 μs. These results indicate that the input stage of the trigeminal pathway has extraordinary spike-timing precision and very high potential information capacity. This timing precision ranks among the highest in biology. PMID:25878266

  4. Reliability Investigations on SnAg Bumps on Substrate Pads with Different Pad Finish

    SciTech Connect

    Bauer, R.; Ebersberger, B.; Kupfer, C.; Alexa, L.

    2006-02-07

    SnAg solder bump is one bump type which is used to replace eutectic SnPb bumps. In this work tests have been done to characterize the reliability properties of this bump type. Electromigration (EM) tests, which were accelerated by high current and high temperature and high temperature storage (HTS) tests were performed. It was found that the reliability properties are sensitive to the material combinations in the interconnect stack. The interconnect stack includes substrate pad, pad finish, bump, underbump metallization (UBM) and the chip pad. Therefore separate test groups for SnAg bumps on Cu substrate pads with organic solderability preservative (OSP) finish and the identical bumps on pads with Ni/Au finish were used. In this paper the reliability test results and the corresponding failure analysis are presented. Some explanations about the differences in formation of intermetallic compounds (IMCs) are given.

  5. Multiple Tune Jumps to Overcome Horizontal Depolarizing Resonances

    NASA Astrophysics Data System (ADS)

    Huang, H.; Ahrens, L. A.; Bai, M.; Brown, K. A.; Dutheil, Y.; Gardner, C.; Glenn, J. W.; Lin, F.; Mackay, W. W.; Meot, F.; Poblaguev, A.; Ranjbar, V.; Roser, T.; Schoefer, V.; Tepikian, S.; Tsoupas, N.; Yip, K.; Zelenski, A.; Zeno, K.

    2016-02-01

    Imperfection and vertical intrinsic depolarizing resonances have been overcome by the two partial Siberian snakes in the Alternative Gradient Synchrotron(AGS). The relatively weak but numerous horizontal resonances are the main source of polarization loss in the AGS. A pair of horizontal tune jump quads have been used to overcome these weak resonances. The locations of the two quads have to be chosen such that the disturbance to the beam optics is minimum. The emittance growth has to be mitigated for this method to work. In addition, this technique needs very accurate jump timing. Using two partial Siberian snakes, with vertical tune inside the spin tune gap and 80% polarization at AGS injection, polarized proton beam had reached 1.5 × 1011 proton per bunch with 65% polarization. With the tune jump timing optimized and emittance preserved, more than 70% polarization with 2 × 1011 protons per bunch has been achieved.

  6. Rayleigh scattering and depolarization ratio in linear alkylbenzene

    NASA Astrophysics Data System (ADS)

    Liu, Qian; Zhou, Xiang; Huang, Wenqian; Zhang, Yuning; Wu, Wenjie; Luo, Wentai; Yu, Miao; Zheng, Yangheng; Zhou, Li; Cao, Jun; Wang, Yifang

    2015-09-01

    It is planned to use linear alkylbenzene (LAB) as the organic solvent for the Jiangmen Underground Neutrino Observatory (JUNO) liquid scintillator detectors, due to its ultra-transparency. However, the current Rayleigh scattering length calculation for LAB disagrees with the experimental measurement. This paper reports for the first time that the Rayleigh scattering of LAB is anisotropic, with a depolarization ratio of 0.31±0.01(stat.)±0.01(sys.). We use an indirect method for Rayleigh scattering measurement with the Einstein-Smoluchowski-Cabannes formula, and the Rayleigh scattering length of LAB is determined to be 28.2±1.0 m at 430 nm.

  7. Experimental verification of depolarization effects in bioelectrical impedance measurement.

    PubMed

    Chen, Xiaoyan; Lv, Xinqiang; Du, Meng

    2014-01-01

    The electrode polarization effects on bioelectrical impedance measurement at low-frequency cannot be ignored. In this paper, the bioelectrical data of mice livers are measured to specify the polarization effects on the bio-impedance measurement data. We firstly introduce the measurement system and methodology. Using the depolarization method, the corrected results are obtained. Besides, the specific effects of electrode polarization on bio-impedance measurement results are investigated using comparative analysis of the previous and posterior correction results from dielectric spectroscopy, Cole-Cole plot, conductivity and spectroscopy of dissipation tangent. Experimental results show that electrode polarization has a significant influence on the characteristic parameters of mouse liver tissues. To be specific, we see a low-frequency limit resistance R0 increase by 19.29%, a reactance peak XP increase by 8.50%, a low-frequency limit conductivity Kl decrease by 17.65% and a dissipation peak tangent decrease by 160%. PMID:25227082

  8. Special Effects: Antenna Wetting, Short Distance Diversity and Depolarization

    NASA Technical Reports Server (NTRS)

    Acosta, Roberto J.

    2000-01-01

    The Advanced Communication Technology Satellite (ACTS) communications system operates in the Ka frequency band. ACTS uses multiple, hopping, narrow beams and very small aperture terminal (VSAT) technology to establish a system availability of 99.5% for bit-error-rates of 5 x 10(exp -7) Or better over the continental United States. In order maintain this minimum system availability in all US rain zones, ACTS uses an adaptive rain fade compensation protocol to reduce the impact of signal attenuation resulting from propagation effects. The purpose of this paper is to present the results of system and sub-system characterizations considering the statistical effects of system variances due to antenna wetting and depolarization effects. In addition the availability enhancements using short distance diversity in a sub-tropical rain zone are investigated.

  9. Depolarization of decaying counterflow turbulence in He II.

    PubMed

    Barenghi, C F; Gordeev, A V; Skrbek, L

    2006-08-01

    We present experimental evidence backed up by numerical simulations that the steady-state vortex tangle created in He II by heat-transfer counterflow is strongly polarized. When the heater that generates the counterflow turbulence is switched off, the vortex tangle decays, the vortex lines randomize their spatial orientation and the tangle's polarization decreases. The process of depolarization slows down the recovery of the transverse second sound signal which measures the vortex line density; at some values of parameters it even leads to a net decrease of the amplitude of the transverse second sound prior to reaching the universal -32 power temporal law decay typical of classical homogeneous isotropic turbulence in a finite-sized channel. PMID:17025541

  10. Depolarization of decaying counterflow turbulence in He II

    SciTech Connect

    Barenghi, C. F.; Gordeev, A. V.; Skrbek, L.

    2006-08-15

    We present experimental evidence backed up by numerical simulations that the steady-state vortex tangle created in He II by heat-transfer counterflow is strongly polarized. When the heater that generates the counterflow turbulence is switched off, the vortex tangle decays, the vortex lines randomize their spatial orientation and the tangle's polarization decreases. The process of depolarization slows down the recovery of the transverse second sound signal which measures the vortex line density; at some values of parameters it even leads to a net decrease of the amplitude of the transverse second sound prior to reaching the universal -3/2 power temporal law decay typical of classical homogeneous isotropic turbulence in a finite-sized channel.

  11. Pad testing in incontinent women: a review.

    PubMed

    Ryhammer, A M; Djurhuus, J C; Laurberg, S

    1999-01-01

    This article reviews the literature on pad-weighing tests used for objectifying and quantifying incontinence in urinary incontinent women. The patients wear pads weighed before and after the test period. A weight gain is taken as a measure of the amount of urine loss. The tests are in principle of two different types: short-term office tests and long-term home tests, and measure different aspects of urinary control and dysfunction. Both have an inherent large intra- and interindividual variability. Pad weight gains obtained from patients referred for incontinence and those from self-reported continent controls overlap to a certain degree, and it is not possible to identify distinct numerical cut-off values separating continence from incontinence. This suggests that incontinence is a complex condition in which the amount of leakage, other sources of weight gain, and differences in the individual patients' personal characteristics influence the identification and quantification of the problem. In spite of the shortcomings the pad tests remain a valuable tool for both the clinician and the researcher. The home pad tests are superior to the office tests in terms of authenticity, and should be performed with a concomitant systematic registration of the participant's voidings, fluid intake and episodes of incontinence. PMID:10384973

  12. Differential distribution of voltage-gated channels in myelinated and unmyelinated baroreceptor afferents.

    PubMed

    Schild, John H; Kunze, Diana L

    2012-12-24

    hallmark of myelinated baroreceptors. Interestingly, HCN2 and HCN4 expression levels are comparable in both fiber types. Collectively, such apportion of VGC constrains the neural coding of myelinated A-type baroreceptors to low threshold, high frequency, high fidelity discharge but with a limited capacity for neuromodulation of afferent bandwidth. Unmyelinated C-type baroreceptors require greater depolarizing forces for spike initiation and have a low frequency discharge profile that is often poorly correlated with the physiological stimulus. But the complement of VGC in C-type neurons provides far greater capacity for neuromodulation of cell excitability than can be obtained from A-type baroreceptors. PMID:23146622

  13. Phytoalexin-Deficient Mutants of Arabidopsis Reveal That Pad4 Encodes a Regulatory Factor and That Four Pad Genes Contribute to Downy Mildew Resistance

    PubMed Central

    Glazebrook, J.; Zook, M.; Mert, F.; Kagan, I.; Rogers, E. E.; Crute, I. R.; Holub, E. B.; Hammerschmidt, R.; Ausubel, F. M.

    1997-01-01

    We are working to determine the role of the Arabidopsis phytoalexin, camalexin, in protecting the plant from pathogen attack by isolating phytoalexin-deficient (pad) mutants in the accession Columbia (Col-0) and examining their response to pathogens. Mutations in PAD1, PAD2, and PAD4 caused enhanced susceptibility to the bacterial pathogen Pseudomonas syringae pv. maculicola strain ES4326 (PsmES4326), while mutations in PAD3 or PAD5 did not. Camalexin was not detected in any of the double mutants pad1-1 pad2-1, pad1-1 pad3-1 or pad2-1 pad3-1. Growth of PsmES4326 in pad1-1 pad2-1 was greater than that in pad1-1 or pad2-1 plants, while growth in pad1-1 pad3-1 and pad2-1 pad3-1 plants was similar to that in pad1-1 and pad2-1 plants, respectively. The pad4-1 mutation caused reduced camalexin synthesis in response to PsmES4326 infection, but not in response to Cochliobolus carbonum infection, indicating that PAD4 has a regulatory function. PAD1, PAD2, PAD3 and PAD4 are all required for resistance to the eukaryotic biotroph Peronospora parasitica. The pad4-1 mutation caused the most dramatic change, exhibiting full susceptibility to four of six Col-incompatible parasite isolates. Interestingly, each combination of double mutants between pad1-1, pad2-1 and pad3-1 exhibited additive shifts to moderate or full susceptibility to most of the isolates. PMID:9136026

  14. Interdependency between mechanical parameters and afferent nerve discharge in hypertrophic intestine of rats.

    PubMed

    Yang, Jian; Zhao, Jingbo; Chen, Pengmin; Nakaguchi, Toshiya; Grundy, David; Gregersen, Hans

    2016-03-15

    Partial intestinal obstruction causes smooth muscle hypertrophy, enteric neuronal plasticity, motility disorders, and biomechanical remodeling. In this study we characterized the stimulus-response function of afferent fibers innervating the partially obstructed jejunum. A key question is whether changes in afferent firing arise from remodeled mechanical tissue properties or from adaptive afferent processes. Partial obstruction was created by placing a polyethylene ring for 2 wk in jejunum of seven rats. Sham obstruction was made in six rats and seven rats served as normal controls. Firing from mesenteric afferent nerve bundles was recorded during mechanical ramp, relaxation, and creep tests. Stress-strain, spike rate increase ratio (SRIR), and firing rate in single units were assessed for evaluation of interdependency of the mechanical stimulations, histomorphometry data, and afferent nerve discharge. Partial intestinal obstruction resulted in hypertrophy and jejunal stiffening proximal to the obstruction site. Low SRIR at low strains during fast distension and at high stresses during slow distension was found in the obstructed rats. Single unit analysis showed increased proportion of mechanosensitive units but absent high-threshold (HT) units during slow stimulation, decreased number of HT units during fast stimulation, and shift from HT sensitivity towards low threshold sensitivity in the obstructed jejunum. Biomechanical remodeling and altered afferent response to mechanical stimulations were found in the obstructed jejunum. Afferents from obstructed jejunum preserved their function in encoding ongoing mechanical stimulation but showed changes in their responsiveness. The findings support that mechanical factors rather than adaption are important for afferent remodeling. PMID:26585414

  15. AGS tune jump system to cross horizontal depolarization resonances overview

    SciTech Connect

    Glenn, J.W.; Ahrens, L.; Fu, W.; Mi, J.L.; Rosas, P.; Schoefer, V.; Theisen, C.; Altinbas, Z.

    2011-03-28

    Two partial snakes overcome the vertical depolarizing resonances in the AGS. But a new type of depolarizing intrinsic resonance from horizontal motion appeared. We reduce these using horizontal tune jumps timed to these resonances. We gain a factor of six in crossing rate with a tune jump of 0.05 in 100 {micro}s. Two quadrapoles, we described in 2009, pulse 42 times, the current matching beam energy. The power supplies for these quads are described in detail elsewhere in this conference. The controls for the Jump Quad system is based on a BNL designed Quad Function Generator. Two modules are used; one for timing, and one to supply reference voltages. Synchronization is provided by a proprietary serial bus, the Event Link. The AgsTuneJump application predicts the times of the resonances during the AGS cycle and calculates the power supply trigger times from externally collected tune and energy versus time data and the Low and High PS voltage functions from a voltage to current model of the power supply. The system was commissioned during runs 09 & 10 and is operational. Many beam effects are described elsewhere. The TuneJump system has worked well and has caused little trouble save for the perturbations in the lattice having such a large effect due to our need to run with the vertical tune within a few thousandths of the integer tune. As these problems were mostly sorted out by correcting the 6th harmonic orbit distortions which caused a large 18 theta beta wave. Also running with minimal chromaticity reduces emittance growth. There are still small beta waves which are being addressed. The timing of the pulses is still being investigated, but as each crossing causes minimal polarization loss, this is a lengthy process.

  16. Perceptual responses to microstimulation of single afferents innervating joints, muscles and skin of the human hand.

    PubMed Central

    Macefield, G; Gandevia, S C; Burke, D

    1990-01-01

    1. Microneurographic techniques were used to isolate single afferent axons within cutaneous and motor fascicles of the median and ulnar nerves at the wrist in thirteen subjects. Of the sixty-five identified afferents, eleven innervated the interphalangeal and metacarpophalangeal joints, sixteen innervated muscle spindles, three innervated Golgi tendon organs and thirty-five supplied the glabrous skin of the hand. 2. Intrafascicular stimulation through the recording microelectrode, using trains of constant-voltage positive pulses (0.3-0.8 V, 0.1-0.2 ms, 1-100 Hz) or constant-current biphasic pulses (0.4-13.0 microA, 0.2 ms, 1-100 Hz), evoked specific sensations from sites associated with some afferent species but not others. 3. Microstimulation of eight of the eleven joint afferent sites (73%) evoked specific sensations. With four, subjects reported innocuous deep sensations referred to the relevant joint. With the other four, the subjects reported a sensation of joint displacement that partially reflected the responsiveness of the afferents to joint rotation. 4. Microstimulation of fourteen of the sixteen muscle spindle afferent sites (88%) generated no perceptions when the stimuli did not produce overt movement. However, subjects could correctly detect the slight movements generated when the stimuli excited the motor axons to the parent muscle. 5. With seven of the nine rapidly adapting (type RA or FAI) cutaneous afferents (88%) microstimulation evoked sensations of 'flutter-vibration', and with two of eight slowly adapting (type SAI) afferents (25%) it evoked sensations of 'sustained pressure'. Of the eighteen SAII afferents, which were classified as such by their responses to planar skin stretch, the majority (83%) generated no perceptions, confirming previous work, but three evoked sensations of movements or pressure. 6. The present results suggest a relatively secure transmission of joint afferent traffic to perceptual levels, and it is concluded that the

  17. Depolarized FRET (depolFRET) on the cell surface: FRET control by photoselection.

    PubMed

    Bene, László; Gogolák, Péter; Ungvári, Tamás; Bagdány, Miklós; Nagy, István; Damjanovich, László

    2016-02-01

    Sensitivity of FRET in hetero- and homo-FRET systems on the photoselected orientation distribution of donors has been proven by using polarized and depolarized light for excitation. FRET as well as donor and acceptor anisotropies have been simultaneously measured in a dual emission-polarization scheme realized in a conventional flow cytometer by using single laser excitation and applying fluorophore-conjugated mAbs against the MHCI and MHCII cell surface receptors. Depolarization of the originally polarized light have been achieved by using crystal depolarizers based on Cornu's principle, a quarter-wave plate for circular polarization, and a parallel beam splitter acting as a diagonal-polarizer for dual-polarization excitation. Simultaneous analysis of intensity-based FRET efficiency and acceptor depolarization equivocally report that depolarization of light may increase FRET in an amount depending on the acceptor-to-donor concentration ratio. Acceptor depolarization turned to be more sensitive to FRET than donor hyper-polarization and even than intensity-based FRET efficiency. It can be used as a sensitive tool for monitoring changes in the dynamics of the donor-acceptor pairs. The basic observations of FRET enhancement and increased acceptor depolarization obtained for hetero-FRET are paralleled by analog observations of homo-FRET enhancements under depolarized excitation. In terms of the orientation factor for FRET, the FRET enhancements on depolarization in the condition of the macroscopically isotropic orientation distributions such as those of the cell surface bound fluorophores report on the presence of local orientation mismatches of the donor and acceptor preventing the optimal FRET in the polarized case, which may be eliminated by the excitation depolarization. A theory of fluorescence anisotropy for depolarized excitation is also presented. PMID:26657258

  18. Spacecraft factory-to-pad testing concept

    NASA Technical Reports Server (NTRS)

    Jones, R. H.

    1975-01-01

    It is noted that the concept of factory-to-pad testing is based on the shipment of a flight-ready spacecraft to the launch base and can be achieved by thorough and comprehensive factory testing of the spacecraft. The principal objectives and results of this approach are shown to be significant cost reductions, increased test effectiveness, and fewer flight problems. Key elements for this concept's success are discussed, including factory-to-pad commonality of support equipment, test requirements and procedures, test teams, and computer programs. Applications of this approach in the space-shuttle era are considered, and a preliminary factory-to-pad concept for the Large Space Telescope spacecraft is presented.

  19. Electrophysiological Properties of Dural Afferents in the Absence and Presence of Inflammatory Mediators

    PubMed Central

    Harriott, Andrea M.; Gold, Michael S.

    2009-01-01

    Migraine is a debilitating condition characterized by recurrent severe head pain. Although mechanisms underlying a migraine attack remain controversial, one proposal is that inflammatory mediator (IM)–induced activation and sensitization of dural afferents contribute to the initiation of migraine pain. We and others have shown that the electrophysiological properties of afferents, both in the absence and the presence of IM, vary as a function of target of innervation. These differences may account for unique aspects of pain syndromes associated with specific body regions. Therefore the purpose of the present study was to test the hypothesis that the electrophysiological properties of dural afferents differ from those innervating the temporalis muscle (TM), a structure in close proximity to the dura but that is not associated with pain syndromes at all similar to migraine. Acutely dissociated retrograde labeled primary afferents innervating the dura and TM were examined with whole cell current-clamp recordings. Passive and active electrophysiological properties were determined before and after the application of IM: (in μM) prostaglandin E2 (1), bradykinin (10), and histamine (1). In the absence of IM, there were significant differences between the two populations, particularly with respect to the response to suprathreshold stimulation where dural afferents were more excitable than TM afferents. Importantly, although both populations of afferents were sensitized by IM, the pattern of passive and active electrophysiological changes associated with IM-induced sensitization of these two populations of afferents suggested that there were both similarities and marked differences between the two with respect to underlying mechanisms of sensitization. If the differences between dural and TM afferents are due to a differential pattern of ion channel expression rather than differences in the relative density/biophysical properties of the same ion channels, it may be

  20. Transient contractions of urinary bladder smooth muscle are drivers of afferent nerve activity during filling.

    PubMed

    Heppner, Thomas J; Tykocki, Nathan R; Hill-Eubanks, David; Nelson, Mark T

    2016-04-01

    Activation of afferent nerves during urinary bladder (UB) filling conveys the sensation of UB fullness to the central nervous system (CNS). Although this sensory outflow is presumed to reflect graded increases in pressure associated with filling, UBs also exhibit nonvoiding, transient contractions (TCs) that cause small, rapid increases in intravesical pressure. Here, using an ex vivo mouse bladder preparation, we explored the relative contributions of filling pressure and TC-induced pressure transients to sensory nerve stimulation. Continuous UB filling caused an increase in afferent nerve activity composed of a graded increase in baseline activity and activity associated with increases in intravesical pressure produced by TCs. For each ∼4-mmHg pressure increase, filling pressure increased baseline afferent activity by ∼60 action potentials per second. In contrast, a similar pressure elevation induced by a TC evoked an ∼10-fold greater increase in afferent activity. Filling pressure did not affect TC frequency but did increase the TC rate of rise, reflecting a change in the length-tension relationship of detrusor smooth muscle. The frequency of afferent bursts depended on the TC rate of rise and peaked before maximum pressure. Inhibition of small- and large-conductance Ca(2+)-activated K(+)(SK and BK) channels increased TC amplitude and afferent nerve activity. After inhibiting detrusor muscle contractility, simulating the waveform of a TC by gently compressing the bladder evoked similar increases in afferent activity. Notably, afferent activity elicited by simulated TCs was augmented by SK channel inhibition. Our results show that afferent nerve activity evoked by TCs represents the majority of afferent outflow conveyed to the CNS during UB filling and suggest that the maximum TC rate of rise corresponds to an optimal length-tension relationship for efficient UB contraction. Furthermore, our findings implicate SK channels in controlling the gain of sensory

  1. Functional recovery of anterior semicircular canal afferents following hair cell regeneration in birds

    NASA Technical Reports Server (NTRS)

    Boyle, Richard; Highstein, Stephen M.; Carey, John P.; Xu, Jinping

    2002-01-01

    Streptomycin sulfate (1.2 g/kg i.m.) was administered for 5 consecutive days to 5-7-day-old white Leghorn chicks; this causes damage to semicircular canal hair cells that ultimately regenerate to reform the sensory epithelium. During the recovery period, electrophysiological recordings were taken sequentially from anterior semicircular canal primary afferents using an indentation stimulus of the canal that has been shown to mimic rotational stimulation. Chicks were assigned to an early (14-18 days; n = 8), intermediate (28-34 days; n = 5), and late (38-58 days; n = 4) period based on days after treatment. Seven untreated chicks, 15-67 days old, provided control data. An absence of background and indent-induced discharge was the prominent feature of afferents in the early period: only "silent" afferents were encountered in 5/8 experiments. In several of these chicks, fascicles of afferent fibers were seen extending up to the epithelium that was void of hair cells, and intra- and extracellular biocytin labeling revealed afferent processes penetrating into the supporting cell layer of the crista. In 3/8 chicks 74 afferents could be characterized, and they significantly differed from controls (n = 130) by having a lower discharge rate and a negligible response to canal stimulation. In the intermediate period there was considerable variability in discharge properties of 121 afferents, but as a whole the number of "silent" fibers in the canal nerve diminished, the background rate increased, and a response to canal stimulation detected. Individually biocytin-labeled afferents had normal-appearing terminal specializations in the sensory epithelium by 28 days poststreptomycin. In the late period, afferents (n = 58) remained significantly different from controls in background discharge properties and response gain. The evidence suggests that a considerable amount of variability exists between chicks in the return of vestibular afferent function following ototoxic injury and

  2. On Depolarization Lidar-Based Method for The Determination of Liquid-Cloud Microphysical Properties

    NASA Astrophysics Data System (ADS)

    Roy, Gilles; Cao, Xiaoying; Tremblay, Grégoire; Bernier, Robert

    2016-06-01

    Under single scattering conditions, water droplets clouds do not depolarize the backscattered light. However, backscattered light from multiple scattering will be depolarized. The level of depolarization is a function of the droplets size, the cloud extinction coefficient value and profile; it has also an important dependency on the lidar field-of-view (FOV). The use of depolarization information to retrieve cloud microphysical properties, using Multiple-FOV has been the object of studies, [1], [2]. Recently the use of the depolarization, at a single FOV, has been studied for cloud with linear liquid water content profiles, [3], [4]. In this paper we present the mechanism leading to depolarization and identify the FOV values for which the information on particle size is high. Also Monte Carlo simulations for cloud with constant and ramp up profiles are presented. The degree of linear depolarization as a function of cloud penetration is significantly different for both cloud profiles. This suggests that the use of the degree of linear depolarization at a single FOV should be used with caution to determine clouds micro-physical parameters.

  3. Treg engage lymphotoxin beta receptor for afferent lymphatic transendothelial migration

    PubMed Central

    Brinkman, C. Colin; Iwami, Daiki; Hritzo, Molly K.; Xiong, Yanbao; Ahmad, Sarwat; Simon, Thomas; Hippen, Keli L.; Blazar, Bruce R.; Bromberg, Jonathan S.

    2016-01-01

    Regulatory T cells (Tregs) are essential to suppress unwanted immunity or inflammation. After islet allo-transplant Tregs must migrate from blood to allograft, then via afferent lymphatics to draining LN to protect allografts. Here we show that Tregs but not non-Treg T cells use lymphotoxin (LT) during migration from allograft to draining LN, and that LT deficiency or blockade prevents normal migration and allograft protection. Treg LTαβ rapidly modulates cytoskeletal and membrane structure of lymphatic endothelial cells; dependent on VCAM-1 and non-canonical NFκB signalling via LTβR. These results demonstrate a form of T-cell migration used only by Treg in tissues that serves an important role in their suppressive function and is a unique therapeutic focus for modulating suppression. PMID:27323847

  4. Interleukin-1β sensitizes abdominal visceral afferents of cats to ischaemia and histamine

    PubMed Central

    Fu, Liang-Wu; Longhurst, John C

    1999-01-01

    Activation of abdominal splanchnic visceral afferents during mesenteric ischaemia induces visceral pain and evokes excitatory cardiovascular responses. Previous studies have shown that interleukin-1β (IL-1β) concentration is increased locally in tissues during ischaemia and reperfusion. Local administration of IL-1β sensitizes somatic afferents to mechanical, thermal and chemical stimulation. Therefore, we hypothesized that IL-1β stimulates or sensitizes splanchnic visceral afferents to ischaemia and to the action of chemical stimuli such as histamine. The concentration of IL-1β in mesenteric lymph and portal venous plasma in anaesthetized cats was measured with an enzyme-linked immunosorbent assay before, during and after 10 min of abdominal ischaemia. The level of IL-1β was significantly increased during ischaemia in lymph, but not in plasma. Discharge activity of single-unit abdominal visceral C fibre afferents was measured from the right thoracic sympathetic chain. Ischaemically sensitive C fibre afferents were identified according to their response to 5–10 min of abdominal ischaemia. Intra-arterial (i.a.) injection of a high dose of IL-1β (500 ng kg−1), but not of a lower dose (i.e. 15, 50 or 150 ng kg−1), stimulated most (six of seven) abdominal visceral afferents. IL-1β (15 ng kg−1, i.a.) significantly enhanced the increased activity of 11 of 13 C fibre afferents during 10 min of ischaemia. Conversely, an IL-1 type I receptor antagonist (IL-1ra, 1·5 μg kg−1, i.a.) significantly attenuated the increased activity in six of seven other C fibre afferents during ischaemia. IL-1β (15 ng kg−1, i.a.) significantly augmented the responses of 13 of 16 ischaemically sensitive abdominal afferents to histamine (5–10 μg kg−1, i.a.). Conversely, IL-1ra (1·5 μg kg−1, i.a.) significantly attenuated the responses of five of six other C fibre afferents to histamine. These data strongly suggest that stimulation of IL-1 type I receptors by IL-1

  5. Electrostatic Evaluation of the SRB Velostat(Trademark) Pads

    NASA Technical Reports Server (NTRS)

    Buhler, Charles R.; Calle, Carlos I.

    2007-01-01

    During RSRM Grain inspection, pads constructed of Velostat are grounded and installed in the RSRM bore enabling inspectors to move throughout the bore during the inspection. Velostat pads are installed by grounding the first pad installed and subsequent pads are installed overlapping the previously installed pad maintaining a conductive path to facility ground. Pads are removed upon completion of the inspection in a reverse fashion. As the pads are removed scanning of propellant surfaces is performed per OMRS. During PPICI Audit of B5308.006 (Forward Segment Grain Inspection) in October 07 one audit finding noted that electrostatic scanning of propellant surfaces was being performed during removal of conductive pads following grain inspection. ATK does not perform electrostatic scanning of propellant surfaces during pad removal following final inspection at the plant. The integrated team consisting of NASA SE, USA SE, USA QE, ATK LSS, ATK Systems Safety and ATK DE concurred that electrostatic scanning of propellant surfaces was unnecessary as the conductive pads are grounded. Additional time spent in bore performing scanning presents itself as additional risk. Technicians reported that they have never seen any voltage readings while scanning propellant surfaces during pad removal. USA Systems engineering has written KB 17530 in response to the finding which will delete the requirement (item 2 B47GEN.ll0) to scan propellant surfaces during pad removal. As a result of an E3 panel discussion on December 13, 2007, it was decided that verification of the electrical grounding of the Velostat pads be verified.

  6. Localization of TRPV1 and P2X3 in unmyelinated and myelinated vagal afferents in the rat.

    PubMed

    Hermes, Sam M; Andresen, Michael C; Aicher, Sue A

    2016-03-01

    The vagus nerve is dominated by afferent fibers that convey sensory information from the viscera to the brain. Most vagal afferents are unmyelinated, slow-conducting C-fibers, while a smaller portion are myelinated, fast-conducting A-fibers. Vagal afferents terminate in the nucleus tractus solitarius (NTS) in the dorsal brainstem and regulate autonomic and respiratory reflexes, as well as ascending pathways throughout the brain. Vagal afferents form glutamatergic excitatory synapses with postsynaptic NTS neurons that are modulated by a variety of channels. The organization of vagal afferents with regard to fiber type and channels is not well understood. In the present study, we used tract tracing methods to identify distinct populations of vagal afferents to determine if key channels are selectively localized to specific groups of afferent fibers. Vagal afferents were labeled with isolectin B4 (IB4) or cholera toxin B (CTb) to detect unmyelinated and myelinated afferents, respectively. We find that TRPV1 channels are preferentially found in unmyelinated vagal afferents identified with IB4, with almost half of all IB4 fibers showing co-localization with TRPV1. These results agree with prior electrophysiological findings. In contrast, we found that the ATP-sensitive channel P2X3 is found in a subset of both myelinated and unmyelinated vagal afferent fibers. Specifically, 18% of IB4 and 23% of CTb afferents contained P2X3. The majority of CTb-ir vagal afferents contained neither channel. Since neither channel was found in all vagal afferents, there are likely further degrees of heterogeneity in the modulation of vagal afferent sensory input to the NTS beyond fiber type. PMID:26706222

  7. Padé approximations and diophantine geometry

    PubMed Central

    Chudnovsky, D. V.; Chudnovsky, G. V.

    1985-01-01

    Using methods of Padé approximations we prove a converse to Eisenstein's theorem on the boundedness of denominators of coefficients in the expansion of an algebraic function, for classes of functions, parametrized by meromorphic functions. This result is applied to the Tate conjecture on the effective description of isogenies for elliptic curves. PMID:16593552

  8. Momument at Pad 14 honoring Project Mercury

    NASA Technical Reports Server (NTRS)

    1966-01-01

    Momument at Pad 14 honoring Project Mercury. The Arabic number 7 represents the seven original astronauts. The other figure is the astronomical symbol of the Planet Mercury. In background is the Gemini 12 Agena Target Docking Vehicle atop its Atlas launch vehicle at Cape Kennedy, Florida.

  9. Hemangioma of the buccal fat pad

    PubMed Central

    Hassani, Ali; Saadat, Sarang; Moshiri, Roya; Shahmirzadi, Solaleh

    2014-01-01

    Hemangiomas are benign vascular neoplasms characterized by an abnormal proliferation of blood vessels. Buccal fat pad (BFP) is a rare place for hemangioma. In this report, clinical, radiographic, and histopathological findings are described in a rare case of hemangioma with phleboliths involving the BFP, and a review is made of the international literature on this subject. PMID:24963256

  10. Antares Rolls Out to Wallops Launch Pad

    NASA Video Gallery

    Orbital Sciences Corporation’s Antares rocket rolls out to the launch pad at NASA’s Wallops Flight Facility on the morning of Oct. 1, 2012. Over the next several months, Orbital plans a hot-fir...

  11. Cutting a Tapered Edge on Padding Material

    NASA Technical Reports Server (NTRS)

    Mitchell, M. J.

    1982-01-01

    Resilience and flexibility of felt, rubber, or other padding materials allow them to be clamped in form block, cut straight down, and then released to produce straight clean tapered edge. With material held in slanted position, edge can be cut straight down; hence cut depth is minimum.

  12. Multivariate Padé Approximations For Solving Nonlinear Diffusion Equations

    NASA Astrophysics Data System (ADS)

    Turut, V.

    2015-11-01

    In this paper, multivariate Padé approximation is applied to power series solutions of nonlinear diffusion equations. As it is seen from tables, multivariate Padé approximation (MPA) gives reliable solutions and numerical results.

  13. Prevent P.A.D.: Know Your Numbers

    MedlinePlus

    ... Issue Past Issues Special Section Prevent P.A.D.: Know Your Numbers Past Issues / Summer 2008 Table ... Best "Timely detection and treatment of P.A.D. are critical," says Dr. Patrice Desvigne-Nickens of ...

  14. Distribution of presumptive chemosensory afferents with FMRFamide- or substance P-like immunoreactivity in decapod crustaceans.

    PubMed

    Schmidt, M

    1997-01-23

    In five species of decapod crustaceans--Cherax destructor (crayfish), Carcinus maenas (crab), Homarus americanus (clawed lobster), Eriocheir sinensis (crab), Macrobrachium rosenbergii (shrimp)--immunocytochemical stainings revealed the presence of sensory afferents with FMRFamide-like immunoreactivity in the central nervous system. These afferents were extremely thin, very numerous, and innervated all sensory neuropils except the optic and olfactory lobes. In their target neuropils they gave rise to condensed net- or ball-like terminal structures. Only in Homarus americanus but not in any other studied species immunocytochemistry revealed a separate, non-overlapping class of sensory afferents with substance P-like immunoreactivity. Also the afferents with substance P-like immunoreactivity were very thin and numerous, innervated all sensory neuropils except optic and olfactory lobes, and gave rise to condensed terminal structures. From their morphological characteristics it can be concluded that likely both classes of afferents are chemosensory. The substance P-like immunoreactivity suggests a link with the nociceptor afferents of vertebrates, with which both classes of afferents share several other morphological features. PMID:9037486

  15. Technetium-99m HIDA hepatobiliary scanning in evaluation of afferent loop syndrome

    SciTech Connect

    Sivelli, R.; Farinon, A.M.; Sianesi, M.; Percudani, M.; Ugolotti, G.; Calbiani, B.

    1984-08-01

    A study of 118 patients, operated on with Billroth II gastrectomy for peptic disease and affected by postgastrectomy syndromes, was carried out. Fifty patients were investigated by means of technetium-99m HIDA hepatobiliary scanning. In 18 patients, in whom an afferent loop syndrome was clinically suspected, hepatobiliary scanning demonstrated an altered afferent loop emptying in 8 and atonic distension of the gallbladder without afferent loop motility changes in 10. Among the patients in the first group, four were treated with a biliary diversion surgical procedure and in the second group, two patients underwent cholecystectomy. Our findings indicate that biliary vomiting, right upper abdominal pain pyrosis, and biliary diarrhea in Billroth II gastrectomized patients are not always pathognomonic symptoms of afferent loop syndrome. Technetium-99m HIDA hepatobiliary scanning represents the only diagnostic means of afferent loop syndrome definition. A differential diagnosis of abnormal afferent loop emptying and gallbladder dyskinesia is necessary for the management planning of these patients, and furthermore, when a surgical treatment is required, biliary diversion with Roux-Y anastomosis or Braun's biliary diversion seems the treatment of choice for afferent loop syndrome, whereas cholecystectomy represents the best procedure for atonic distension of the gallbladder.

  16. Frequency response properties of primary afferent neurons in the posterior lateral line system of larval zebrafish.

    PubMed

    Levi, Rafael; Akanyeti, Otar; Ballo, Aleksander; Liao, James C

    2015-01-15

    The ability of fishes to detect water flow with the neuromasts of their lateral line system depends on the physiology of afferent neurons as well as the hydrodynamic environment. Using larval zebrafish (Danio rerio), we measured the basic response properties of primary afferent neurons to mechanical deflections of individual superficial neuromasts. We used two types of stimulation protocols. First, we used sine wave stimulation to characterize the response properties of the afferent neurons. The average frequency-response curve was flat across stimulation frequencies between 0 and 100 Hz, matching the filtering properties of a displacement detector. Spike rate increased asymptotically with frequency, and phase locking was maximal between 10 and 60 Hz. Second, we used pulse train stimulation to analyze the maximum spike rate capabilities. We found that afferent neurons could generate up to 80 spikes/s and could follow a pulse train stimulation rate of up to 40 pulses/s in a reliable and precise manner. Both sine wave and pulse stimulation protocols indicate that an afferent neuron can maintain their evoked activity for longer durations at low stimulation frequencies than at high frequencies. We found one type of afferent neuron based on spontaneous activity patterns and discovered a correlation between the level of spontaneous and evoked activity. Overall, our results establish the baseline response properties of lateral line primary afferent neurons in larval zebrafish, which is a crucial step in understanding how vertebrate mechanoreceptive systems sense and subsequently process information from the environment. PMID:25355959

  17. Hair cell tufts and afferent innervation of the bullfrog crista ampullaris

    NASA Technical Reports Server (NTRS)

    Myers, Steven F.; Lewis, Edwin R.

    1990-01-01

    Within the bullfrog semicircular canal crista, hair cell tuft types were defined and mapped with the aid of scanning electron microscopy. Dye-filled planar afferent axons had mean distal axonal diameters of 1.6-4.9 microns, highly branched arbors, and contacted 11-24 hair cells. Dye-filled isthmus afferent axons had mean distal axonal diameters of 1.8-7.9 microns, with either small or large field arbors contacting 4-9 or 25-31 hair cells. The estimated mean number of contacts per innervated hair cell was 2.2 for planar and 1.3 for isthmus afferent neurons. Data on evoked afferent responses were available only for isthmus units that were observed to respond to our microrotational stimuli. Of 21 such afferent neurons, eight were successfully dye-filled. Within this sample, high-gain units had large field arbors and lower-gain units had small field arbors. The sensitivity of each afferent neuron was analyzed in terms of noise equivalent input (NEI), the stimulus amplitude for which the afferent response amplitude is just equivalent to the rms deviation of the instantaneous spike rate. NEI for isthmus units varied from 0.63 to 8.2 deg/s; the mean was 3.2 deg/s.

  18. Novel Afferent Terminal Structure in the Crista Ampullaris of the Goldfish, Carassius auratus

    NASA Technical Reports Server (NTRS)

    Lanford, Pamela J.; Popper, Arthur N.

    1996-01-01

    Using transmission electron microscopy, we have identified a new type of afferent terminal structure in the crista ampullaris of the goldfish Carassius auratus. In addition to the bouton-type afferent terminals previously described in the ear of this species, the crista also contained enlarged afferent terminals that enveloped a portion of the basolateral hair cell membrane. The hair cell membrane was evaginated and protruded into the afferent terminal in a glove-and-finger configuration. The membranes of the two cells were regularly aligned in the protruded region of the contact and had a distinct symmetrical electron density. The electron-dense profiles of these contacts were easily identified and were present in every crista sampled. In some cases, efferent terminals synapsed onto the afferents at a point where the hair cell protruded into the terminal. The ultrastructural similarities of the goldfish crista afferents to calyx afferents found in amniotes (birds, reptiles, and mammals) are discussed. The results of the study support the hypothesis that structural variation in the vertebrate inner ear may have evolved much earlier in evolution than previously supposed.

  19. Frequency response properties of primary afferent neurons in the posterior lateral line system of larval zebrafish

    PubMed Central

    Levi, Rafael; Akanyeti, Otar; Ballo, Aleksander

    2014-01-01

    The ability of fishes to detect water flow with the neuromasts of their lateral line system depends on the physiology of afferent neurons as well as the hydrodynamic environment. Using larval zebrafish (Danio rerio), we measured the basic response properties of primary afferent neurons to mechanical deflections of individual superficial neuromasts. We used two types of stimulation protocols. First, we used sine wave stimulation to characterize the response properties of the afferent neurons. The average frequency-response curve was flat across stimulation frequencies between 0 and 100 Hz, matching the filtering properties of a displacement detector. Spike rate increased asymptotically with frequency, and phase locking was maximal between 10 and 60 Hz. Second, we used pulse train stimulation to analyze the maximum spike rate capabilities. We found that afferent neurons could generate up to 80 spikes/s and could follow a pulse train stimulation rate of up to 40 pulses/s in a reliable and precise manner. Both sine wave and pulse stimulation protocols indicate that an afferent neuron can maintain their evoked activity for longer durations at low stimulation frequencies than at high frequencies. We found one type of afferent neuron based on spontaneous activity patterns and discovered a correlation between the level of spontaneous and evoked activity. Overall, our results establish the baseline response properties of lateral line primary afferent neurons in larval zebrafish, which is a crucial step in understanding how vertebrate mechanoreceptive systems sense and subsequently process information from the environment. PMID:25355959

  20. Biomechanical Comparison of Shorts With Different Pads

    PubMed Central

    Marcolin, Giuseppe; Petrone, Nicola; Reggiani, Carlo; Panizzolo, Fausto A.; Paoli, Antonio

    2015-01-01

    Abstract An intensive use of the bicycle may increase the risk of erectile dysfunction and the compression of the perineal area has been showed to be a major mechanism leading to sexual alterations compromising the quality of life. Manufacturers claim that pads contribute to increase cyclists perineal protection ensuring a high level of comfort. To investigate the influence of various cycling pads with regard to perineal protection and level of comfort. Nine club road cyclists rode 20 min on a drum simulator, located at the Nutrition and Exercise Physiology Laboratory, at a constant speed and gear ratio wearing the shorts with 3 cycling pads of different design and thickness: basic (BAS), intermediate (INT), and endurance (END). Kinematics and pressure data were recorded at min 5, 15, and 20 of the test using a motion capture system and a pressure sensor mat. The variables of interest were: 3-dimensional pelvis excursions, peak pressure, mean pressure, and vertical force. The comfort level was assessed with a ranking order based on the subjects’ perception after the 20-min trials and measuring the vertical ground reaction force under the anterior wheel as well as the length of the center of pressure (COP) trajectory on the saddle. Results showed that the vertical force and the average value of mean pressure on the saddle significantly decreased during the 20-min period of testing for BAS and END. Mean peak pressure on the corresponding perineal cyclist area significantly increased only for BAS during the 20-min period. Interestingly objective comfort indexes measured did not match cyclists subjective comfort evaluation. The lower capacity of BAS to reduce the peak pressure on the corresponding perineal area after 20 min of testing, together with its positive comfort evaluation, suggest that a balance between protection and perceived comfort should be taken into account in the choice of the pad. Hence, the quantitative approach of objective comfort indexes

  1. A novel method of selective ablation of afferent renal nerves by periaxonal application of capsaicin

    PubMed Central

    Foss, Jason D.; Wainford, Richard D.; Engeland, William C.; Fink, Gregory D.

    2014-01-01

    Renal denervation has been shown to lower arterial pressure in some hypertensive patients, yet it remains unclear whether this is due to ablation of afferent or efferent renal nerves. To investigate the role of afferent renal nerves in arterial pressure regulation, previous studies have used methods that disrupt both renal and nonrenal afferent signaling. The present study was conducted to develop and validate a technique for selective ablation of afferent renal nerves that does not disrupt other afferent pathways. To do this, we adapted a technique for sensory denervation of the adrenal gland by topical application of capsaicin and tested the hypothesis that exposure of the renal nerves to capsaicin (renal-CAP) causes ablation of afferent but not efferent renal nerves. Renal-CAP had no effect on renal content of the efferent nerve markers tyrosine hydroxylase and norepinephrine; however, the afferent nerve marker, calcitonin gene-related peptide was largely depleted from the kidney 10 days after intervention, but returned to roughly half of control levels by 7 wk postintervention. Moreover, renal-CAP abolished the cardiovascular responses to acute pharmacological stimulation of afferent renal nerves. Renal-CAP rats showed normal weight gain, as well as cardiovascular and fluid balance regulation during dietary sodium loading. To some extent, renal-CAP did blunt the bradycardic response and increase the dipsogenic response to increased salt intake. Lastly, renal-CAP significantly attenuated the development of deoxycorticosterone acetate-salt hypertension. These results demonstrate that renal-CAP effectively causes selective ablation of afferent renal nerves in rats. PMID:25411365

  2. The afferent signaling complex: Regulation of type I spiral ganglion neuron responses in the auditory periphery.

    PubMed

    Reijntjes, Daniël O J; Pyott, Sonja J

    2016-06-01

    The spiral ganglion neurons (SGNs) are the first action potential generating neurons in the auditory pathway. The type I SGNs contact the sensory inner hair cells via their peripheral dendrites and relay auditory information to the brainstem via their central axon fibers. Individual afferent fibers show differences in response properties that are essential for normal hearing. The mechanisms that give rise to the heterogeneity of afferent responses are very poorly understood but are likely already in place at the peripheral dendrites where synapses are formed and action potentials are generated. To identify these molecular mechanisms, this review synthesizes a variety of literature and comprehensively outlines the cellular and molecular components positioned to regulate SGN afferent dendrite excitability, especially following glutamate release. These components include 1) proteins of the SGN postsynapses and neighboring supporting cells that together shape glutamatergic signaling, 2) the ion channels and transporters that determine the intrinsic excitability of the SGN afferent dendrites, and 3) the neurotransmitter receptors that extrinsically modify this excitability via synaptic input from the lateral olivocochlear efferents. This cellular and molecular machinery, together with presynaptic specializations of the inner hair cells, can be collectively referred to as the type I afferent signaling complex. As this review underscores, interactions of this signaling complex determine excitability of the SGN afferent dendrites and the afferent fiber responses. Moreover, this complex establishes the environmental milieu critical for the development and maintenance of the SGN afferent dendrites and synapses. Motivated by these important functions, this review also indicates areas of future research to elucidate the contributions of the afferent signaling complex to both normal hearing and also hearing loss. PMID:27018296

  3. Rotor stability estimation with competing tilting pad bearing models

    NASA Astrophysics Data System (ADS)

    Cloud, C. Hunter; Maslen, Eric H.; Barrett, Lloyd E.

    2012-05-01

    When predicting the stability of rotors supported by tilting pad journal bearings, it is currently debated whether or not the bearings should be represented with frequency dependent dynamics. Using an experimental apparatus, measurements of pad temperatures, unbalance response and stability are compared with modeling predictions for two tilting pad bearing designs. Predictions based on frequency dependent tilting pad bearing dynamics exhibited significantly better correlation with the stability measurements than those assuming frequency independent dynamics.

  4. Mitochondrial activity and brain functions during cortical depolarization

    NASA Astrophysics Data System (ADS)

    Mayevsky, Avraham; Sonn, Judith

    2008-12-01

    Cortical depolarization (CD) of the cerebral cortex could be developed under various pathophysiological conditions. In animal models, CD was recorded under partial or complete ischemia as well as when cortical spreading depression (SD) was induced externally or by internal stimulus. The development of CD in patients and the changes in various metabolic parameters, during CD, was rarely reported. Brain metabolic, hemodynamic, ionic and electrical responses to the CD event are dependent upon the O2 balance in the tissue. When the O2 balance is negative (i.e. ischemia), the CD process will be developed due to mitochondrial dysfunction, lack of energy and the inhibition of Na+-K+-ATPase. In contradiction, when oxygen is available (i.e. normoxia) the development of CD after induction of SD will accelerate mitochondrial respiration for retaining ionic homeostasis and normal brain functions. We used the multiparametric monitoring approach that enable real time monitoring of mitochondrial NADH redox state, microcirculatory blood flow and oxygenation, extracellular K+, Ca2+, H+ levels, DC steady potential and electrocorticogram (ECoG). This monitoring approach, provide a unique tool that has a significant value in analyzing the pathophysiology of the brain when SD developed under normoxia, ischemia, or hypoxia. We applied the same monitoring approach to patients suffered from severe head injury or exposed to neurosurgical procedures.

  5. Electromagnetic scattering and depolarization across rough surfaces: Full wave analysis

    NASA Astrophysics Data System (ADS)

    Bahar, Ezekiel; Huang, Guorong; Lee, Bom Son

    1995-05-01

    Full wave solutions are derived for vertically and horizontally polarized waves diffusely scattered across an interface that is two-dimensionally rough separating two different propagating media. Since the normal to the rough surface is not restricted to the reference plane of incidence, the waves are depolarized upon scattering; and the single scattered radiation fields are expressed as integrals of a surface element transmission scattering matrix that also accounts for coupling between the vertically and horizontally polarized waves. The integrations are over the rough surface area as well as the complete two-dimensional wave spectra of the radiation fields. The full wave solutions satisfy the duality and reciprocity relationships in electromagnetic theory, and the surface element scattering matrix is invariant to coordinate transformations. It is shown that in the high-frequency limit the full wave solutions reduce to the physical optics solutions, while in the low-frequency limit (for small mean square heights and slopes) the full wave solutions reduce to Rice's (1951) small perturbation solutions. Thus, the full wave solution accounts for specular point scattering as well as diffuse, Bragg-type scattering in a unified, self-consistent manner. It is therefore not necessary to use hybrid, perturbation and physical optics approaches (based on two-scale models of composite surfaces with large and small roughness scales) to determine the like- and cross-polarized fields scattered across the rough surface.

  6. Faraday signature of magnetic helicity from reduced depolarization

    SciTech Connect

    Brandenburg, Axel; Stepanov, Rodion

    2014-05-10

    Using one-dimensional models, we show that a helical magnetic field with an appropriate sign of helicity can compensate the Faraday depolarization resulting from the superposition of Faraday-rotated polarization planes from a spatially extended source. For radio emission from a helical magnetic field, the polarization as a function of the square of the wavelength becomes asymmetric with respect to zero. Mathematically speaking, the resulting emission occurs then either at observable or at unobservable (imaginary) wavelengths. We demonstrate that rotation measure (RM) synthesis allows for the reconstruction of the underlying Faraday dispersion function in the former case, but not in the latter. The presence of positive magnetic helicity can thus be detected by observing positive RM in highly polarized regions in the sky and negative RM in weakly polarized regions. Conversely, negative magnetic helicity can be detected by observing negative RM in highly polarized regions and positive RM in weakly polarized regions. The simultaneous presence of two magnetic constituents with opposite signs of helicity is shown to possess signatures that can be quantified through polarization peaks at specific wavelengths and the gradient of the phase of the Faraday dispersion function. Similar polarization peaks can tentatively also be identified for the bi-helical magnetic fields that are generated self-consistently by a dynamo from helically forced turbulence, even though the magnetic energy spectrum is then continuous. Finally, we discuss the possibility of detecting magnetic fields with helical and non-helical properties in external galaxies using the Square Kilometre Array.

  7. Effect of depolarization on temporal coherence within a focused supercontinuum

    SciTech Connect

    Chick, Brendan J.; Chon, James W. M.; Gu Min

    2010-08-15

    Under the conditions of vectorial diffraction, an increase in refraction at the extremities of the lens rotates the incident polarization state which transfers energy from the initial state to the orthogonal transverse field and the longitudinal field, which is known as depolarization. Since the field is a vectorial field containing three polarization components, the theory for the degree of coherence is first extended to incorporate cross-correlation effects within these vectorial components which are calculated through a coherency matrix. The use of this matrix provides an insight into interesting correlation effects between copropagating vectorial fields such as the coupled modes (linear polarized modes) of the supercontinuum generated by a photonic crystal fiber. An investigation is presented on the coherence times for the supercontinuum field generated by cross coupling into the photonic crystal fiber. The coherence times under cross-coupling conditions show that the degree of coherence of the two coupled modes from the fiber are different, which is due to the differences in phase. For a supercontinuum with a linear polarization state, the coherence times along the x, y, and z axes are different, with the most significant change occurring along the optical axis (z) where the coherence time changes by an order of magnitude when the numerical aperture is increased from 0.1 to 1.

  8. Enterolith Causing Afferent Loop Obstruction: A Case Report and Literature Review

    SciTech Connect

    Lee, Michael C.; Bui, James T.; Knuttinen, M-Grace; Gaba, Ron C.; Scott Helton, W.; Owens, Charles A.

    2009-09-15

    Enterolith formation is a rare cause of afferent limb obstruction following Billroth II gastrectomy and Roux-en-Y hepaticojejunostomy surgery. A case of ascending cholangitis caused by an enterolith incarcerated in the afferent loop of a 15-year-old Roux-en-Y hepaticojejunostomy was emergently decompressed under direct ultrasound guidance prior to surgery. This is the thirteenth reported case of an enterolith causing afferent loop obstruction. A discussion of our management approach and a review of the relevant literature are presented.

  9. Percutaneous jejunostomy through the liver parenchyma for palliation of afferent loop syndrome.

    PubMed

    Kwon, Jae Hyun; Han, Yoon Hee

    2015-01-01

    In the treatment of afferent loop syndrome, jejunostomy or Roux-en-Y gastrojejunostomy have tended to represent the preferred procedures. In patients who are not good candidates for surgery, palliative treatment-i.e., percutaneous transhepatic biliary drainage or percutaneous direct transperitoneal jejunostomy techniques-have been applied. Transhepatic biliary drainage confers a risk of ascending cholangitis. Direct percutaneous transperitoneal drainage may be impractical when overlying bowel loops prevent access to deeply located afferent loops. In the present case, percutaneous jejunostomy through the liver parenchyma was performed successfully for palliation of afferent loop syndrome. PMID:25433418

  10. 21 CFR 880.5270 - Neonatal eye pad.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Neonatal eye pad. 880.5270 Section 880.5270 Food... § 880.5270 Neonatal eye pad. (a) Identification. A neonatal eye pad is an opaque device used to cover and protect the eye of an infant during therapeutic procedures, such as phototherapy....

  11. 21 CFR 880.5270 - Neonatal eye pad.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Neonatal eye pad. 880.5270 Section 880.5270 Food... § 880.5270 Neonatal eye pad. (a) Identification. A neonatal eye pad is an opaque device used to cover and protect the eye of an infant during therapeutic procedures, such as phototherapy....

  12. 21 CFR 880.5270 - Neonatal eye pad.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Neonatal eye pad. 880.5270 Section 880.5270 Food... § 880.5270 Neonatal eye pad. (a) Identification. A neonatal eye pad is an opaque device used to cover and protect the eye of an infant during therapeutic procedures, such as phototherapy....

  13. 21 CFR 880.5270 - Neonatal eye pad.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Neonatal eye pad. 880.5270 Section 880.5270 Food... § 880.5270 Neonatal eye pad. (a) Identification. A neonatal eye pad is an opaque device used to cover and protect the eye of an infant during therapeutic procedures, such as phototherapy....

  14. 21 CFR 880.5270 - Neonatal eye pad.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Neonatal eye pad. 880.5270 Section 880.5270 Food... § 880.5270 Neonatal eye pad. (a) Identification. A neonatal eye pad is an opaque device used to cover and protect the eye of an infant during therapeutic procedures, such as phototherapy....

  15. A fluopol-ABPP HTS assay to identify PAD inhibitors.

    PubMed

    Knuckley, Bryan; Jones, Justin E; Bachovchin, Daniel A; Slack, Jessica; Causey, Corey P; Brown, Steven J; Rosen, Hugh; Cravatt, Benjamin F; Thompson, Paul R

    2010-10-14

    Protein Arginine Deiminase (PAD) activity is dysregulated in numerous diseases, e.g., Rheumatoid Arthritis. Herein we describe the development of a fluorescence polarization-Activity Based Protein Profiling (fluopol-ABPP) based high throughput screening assay that can be used to identify PAD-selective inhibitors. Using this assay, streptonigrin was identified as a potent, selective, and irreversible PAD4 inactivator. PMID:20740228

  16. iPads in Higher Education--Hype and Hope

    ERIC Educational Resources Information Center

    Nguyen, Lemai; Barton, Siew Mee; Nguyen, Linh Thuy

    2015-01-01

    This paper systematically reviews current research on using iPads in the higher education sector. Since the release of iPads by Apple in 2010, this new technology has been quickly adopted everywhere, especially by the younger generation and professionals. We were motivated to find out how iPads have been adopted for use in the higher education…

  17. Dynamic behavior of air lubricated pivoted-pad journal-bearing, rotor system. 2: Pivot consideration and pad mass

    NASA Technical Reports Server (NTRS)

    Nemeth, Z. N.

    1972-01-01

    Rotor bearing dynamic tests were conducted with tilting-pad journal bearings having three different pad masses and two different pivot geometries. The rotor was vertically mounted and supported by two three-pad tilting-pad gas journal bearings and a simple externally pressurized thrust bearing. The bearing pads were 5.1 cm (2.02 in.) in diameter and 2.8 cm (1.5 in.) long. The length to diameter ratio was 0.75. One pad was mounted on a flexible diaphragm. The bearing supply pressure ranged from 0 to 690 kilonewtons per square meter (0 to 100 psig), and speeds ranged to 38,500 rpm. Heavy mass pad tilting-pad assemblies produced three rotor-bearing resonances above the first two rotor critical speeds. Lower supply pressure eliminated the resonances. The resonances were oriented primarily in the direction normal to the diaphragm.

  18. GluA2-Containing AMPA Receptors Distinguish Ribbon-Associated from Ribbonless Afferent Contacts on Rat Cochlear Hair Cells.

    PubMed

    Martinez-Monedero, Rodrigo; Liu, Chang; Weisz, Catherine; Vyas, Pankhuri; Fuchs, Paul Albert; Glowatzki, Elisabeth

    2016-01-01

    Mechanosensory hair cells release glutamate at ribbon synapses to excite postsynaptic afferent neurons, via AMPA-type ionotropic glutamate receptors (AMPARs). However, type II afferent neurons contacting outer hair cells in the mammalian cochlea were thought to differ in this respect, failing to show GluA immunolabeling and with many "ribbonless" afferent contacts. Here it is shown that antibodies to the AMPAR subunit GluA2 labeled afferent contacts below inner and outer hair cells in the rat cochlea, and that synaptic currents in type II afferents had AMPAR-specific pharmacology. Only half the postsynaptic densities of type II afferents that labeled for PSD-95, Shank, or Homer were associated with GluA2 immunopuncta or presynaptic ribbons, the "empty slots" corresponding to ribbonless contacts described previously. These results extend the universality of AMPAergic transmission by hair cells, and support the existence of silent afferent contacts. PMID:27257620

  19. Depolarization of Cellular Resting Membrane Potential Promotes Neonatal Cardiomyocyte Proliferation In Vitro

    PubMed Central

    Lan, Jen-Yu; Williams, Corin; Levin, Michael; Black, Lauren Deems

    2014-01-01

    Cardiomyocytes (CMs) undergo a rapid transition from hyperplastic to hypertrophic growth soon after birth, which is a major challenge to the development of engineered cardiac tissue for pediatric patients. Resting membrane potential (Vmem) has been shown to play an important role in cell differentiation and proliferation during development. We hypothesized that depolarization of neonatal CMs would stimulate or maintain CM proliferation in vitro. To test our hypothesis, we isolated postnatal day 3 neonatal rat CMs and subjected them to sustained depolarization via the addition of potassium gluconate or Ouabain to the culture medium. Cell density and CM percentage measurements demonstrated an increase in mitotic CMs along with a ~2 fold increase in CM numbers with depolarization. In addition, depolarization led to an increase in cells in G2 and S phase, indicating increased proliferation, as measured by flow cytometry. Surprisingly depolarization of Vmem with either treatment led to inhibition of proliferation in cardiac fibroblasts. This effect is abrogated when the study was carried out on postnatal day 7 neonatal CMs, which are less proliferative, indicating that the likely mechanism of depolarization is the maintenance of the proliferating CM population. In summary, our findings suggest that depolarization maintains postnatal CM proliferation and may be a novel approach to encourage growth of engineered tissue and cardiac regeneration in pediatric patients. PMID:25295125

  20. Assessment of aerosol's mass concentrations from measured linear particle depolarization ratio (vertically resolved) and simulations

    NASA Astrophysics Data System (ADS)

    Nemuc, A.; Vasilescu, J.; Talianu, C.; Belegante, L.; Nicolae, D.

    2013-11-01

    Multi-wavelength depolarization Raman lidar measurements from Magurele, Romania are used in this study along with simulated mass-extinction efficiencies to calculate the mass concentration profiles of different atmospheric components, due to their different depolarization contribution to the 532 nm backscatter coefficient. Linear particle depolarization ratio (δpart) was computed using the relative amplification factor and the system-dependent molecular depolarization. The low depolarizing component was considered as urban/smoke, with a mean δpart of 3%, while for the high depolarizing component (mineral dust) a mean δpart of 35% was assumed. For this study 11 months of lidar measurements were analysed. Two study cases are presented in details: one for a typical Saharan dust aerosol intrusion, 10 June 2012 and one for 12 July 2012 when a lofted layer consisting of biomass burning smoke extended from 3 to 4.5 km height. Optical Properties of Aerosols and Clouds software package (OPAC) classification and conversion factors were used to calculate mass concentrations. We found that calibrated depolarization measurements are critical in distinguishing between smoke-reach aerosol during the winter and dust-reach aerosol during the summer, as well as between elevated aerosol layers having different origins. Good agreement was found between lidar retrievals and DREAM- Dust REgional Atmospheric Model forecasts in cases of Saharan dust. Our method was also compared against LIRIC (The Lidar/Radiometer Inversion Code) and very small differences were observed.

  1. Assessment of aerosol's mass concentrations from measured linear particle depolarization ratio (vertically resolved) and simulations

    NASA Astrophysics Data System (ADS)

    Nemuc, A.; Vasilescu, J.; Talianu, C.; Belegante, L.; Nicolae, D.

    2013-06-01

    Multiwavelength depolarization Raman lidar measurements from Magurele, Romania are used in this study along with simulated mass-extinction efficiencies to calculate the mass concentrations profiles of different atmospheric components, due to their different depolarization contribution to the 532 nm backscatter coefficient. Linear particle depolarization ratio (δpart) was computed using the relative amplification factor and the system-dependent molecular depolarization. The low depolarizing component was considered as urban/smoke, with a mean δpart of 3%, while for the high depolarizing component (mineral dust) a mean δpart of 35% was assumed. For this study 11 months of lidar measurements were analyzed. Two study cases are presented in details: one for a typical Saharan dust aerosol intrusion, 10 June 2012 and one for 12 July 2012 when a lofted layer consisting of biomass burning smoke extended from 3 to 4.5 km height. Optical Properties of Aerosols and Clouds software package (OPAC) classification and conversion factors were used to calculate mass concentrations. We found that calibrated depolarization measurements are critical to distinguish between smoke-reach aerosol during the winter and dust-reach aerosol during the summer, as well as between elevated aerosol layers having different origins. Good agreement was found between lidar retrievals and DREAM- Dust REgional Atmospheric Model forecasts in cases of Saharan dust. Our method was also compared against LIRIC (The Lidar/Radiometer Inversion Code) and very small differences were observed.

  2. Longitudinal polarization periodicity of unpolarized light passing through a double wedge depolarizer.

    PubMed

    de Sande, Juan Carlos G; Santarsiero, Massimo; Piquero, Gemma; Gori, Franco

    2012-12-01

    The polarization characteristics of unpolarized light passing through a double wedge depolarizer are studied. It is found that the degree of polarization of the radiation propagating after the depolarizer is uniform across transverse planes after the depolarizer, but it changes from one plane to another in a periodic way giving, at different distances, unpolarized, partially polarized, or even perfectly polarized light. An experiment is performed to confirm this result. Measured values of the Stokes parameters and of the degree of polarization are in complete agreement with the theoretical predictions. PMID:23262685

  3. Modulation of electromagnetic fields by a depolarizer of random polarizer array.

    PubMed

    Ma, Ning; Hanson, Steen G; Wang, Wei

    2016-05-01

    The statistical properties of the electric fields with random changes of the polarization state in space generated by a depolarizer are investigated on the basis of the coherence matrix. The depolarizer is a polarizer array composed of a multitude of contiguous square cells of polarizers with randomly distributed polarization angles, where the incident fields experience a random polarization modulation after passing through the depolarizer. The propagation of the modulated electric fields through any quadratic optical system is examined within the framework of the complex ABCD matrix to show how the degree of coherence and the degree of polarization change on propagation. PMID:27128058

  4. Speed of disentanglement in multiqubit systems under a depolarizing channel

    SciTech Connect

    Zhang, Fu-Lin Jiang, Yue; Liang, Mai-Lin

    2013-06-15

    We investigate the speed of disentanglement in the multiqubit systems under the local depolarizing channel, in which each qubit is independently coupled to the environment. We focus on the bipartition entanglement between one qubit and the remaining qubits constituting the system, which is measured by the negativity. For the two-qubit system, the speed for the pure state completely depends on its entanglement. The upper and lower bounds of the speed for arbitrary two-qubit states, and the necessary conditions for a state achieving them, are obtained. For the three-qubit system, we study the speed for pure states, whose entanglement properties can be completely described by five local-unitary-transformation invariants. An analytical expression of the relation between the speed and the invariants is derived. The speed is enhanced by the three-tangle which is the entanglement among the three qubits, but reduced by the two-qubit correlations outside the concurrence. The decay of the negativity can be restrained by the other two negativity with the coequal sense. The unbalance between two qubits can reduce the speed of disentanglement of the remaining qubit in the system, and even can retrieve the entanglement partially. For the k-qubit systems in an arbitrary superposition of Greenberger–Horne–Zeilinger state and W state, the speed depends almost entirely on the amount of the negativity when k increases to five or six. An alternative quantitative definition for the robustness of entanglement is presented based on the speed of disentanglement, with comparison to the widely studied robustness measured by the critical amount of noise parameter where the entanglement vanishes. In the limit of large number of particles, the alternative robustness of the Greenberger–Horne–Zeilinger-type states is inversely proportional to k, and the one of the W states approaches 1/√(k)

  5. Neural depolarization triggers Mg2+ influx in rat hippocampal neurons.

    PubMed

    Yamanaka, R; Shindo, Y; Karube, T; Hotta, K; Suzuki, K; Oka, K

    2015-12-01

    Homeostasis of magnesium ion (Mg(2+)) plays key roles in healthy neuronal functions, and deficiency of Mg(2+) is involved in various neuronal diseases. In neurons, we have reported that excitotoxicity induced by excitatory neurotransmitter glutamate increases intracellular Mg(2+) concentration ([Mg(2+)]i). However, it has not been revealed whether neuronal activity under physiological condition modulates [Mg(2+)]i. The aim of this study is to explore the direct relationship between neural activity and [Mg(2+)]i dynamics. In rat primary-dissociated hippocampal neurons, the [Mg(2+)]i and [Ca(2+)]i dynamics were simultaneously visualized with a highly selective fluorescent Mg(2+) probe, KMG-104, and a fluorescent Ca(2+) probe, Fura Red, respectively. [Mg(2+)]i increase concomitant with neural activity by direct current stimulation was observed in neurons plated on an indium-tin oxide (ITO) glass electrode, which enables fluorescent imaging during neural stimulation. The neural activity-dependent [Mg(2+)]i increase was also detected in neurons whose excitability was enhanced by the treatment of a voltage-gated K(+) channel blocker, tetraethylammonium (TEA) at the timings of spontaneous Ca(2+) increase. Furthermore, the [Mg(2+)]i increase was abolished in Mg(2+)-free extracellular medium, indicating [Mg(2+)]i increase is due to Mg(2+) influx induced by neural activity. The direct neuronal depolarization by veratridine, a Na(+) channel opener, induced [Mg(2+)]i increase, and this [Mg(2+)]i increase was suppressed by the pretreatment of a non-specific Mg(2+) channel inhibitor, 2-aminoethoxydiphenyl borate (2-APB). Overall, activity-dependent [Mg(2+)]i increase results from Mg(2+) influx through 2-APB-sensitive channels in rat hippocampal neurons. PMID:26455951

  6. Response properties of gerbil otolith afferents to small angle pitch and roll tilts

    NASA Technical Reports Server (NTRS)

    Dickman, J. D.; Angelaki, D. E.; Correia, M. J.

    1991-01-01

    The responses from isolated single otolith afferent fibers were obtained to small angle sinusoidal pitch and roll tilts in anesthetized gerbils. The stimulus directions that produced the maximum (response vector) and minimum response sensitivities were determined for each otolith afferent, with response vectors for the units being spread throughout the horizontal plane, similar to those reported for other species. A breadth of tuning measure was derived, with narrowly tuned neurons responding maximally to stimulation in one direction and minimally along an orthogonal ('null') direction. Most (approximately 80%) otolith afferents are narrowly tuned, however, some fibers were broadly tuned responding significantly to stimulations in any direction in the horizontal plane. The number of broadly tuned otolith afferents (approximately 20%) differs significantly from the more substantial number of broadly tuned vestibular nuclei neurons (88%) recently reported in rats.

  7. Functional specializations of primary auditory afferents on the Mauthner cells: interactions between membrane and synaptic properties.

    PubMed

    Curti, Sebastian; Pereda, Alberto E

    2010-01-01

    Primary auditory afferents are usually perceived as passive, timing-preserving, lines of communication. Contrasting this view, a special class of auditory afferents to teleost Mauthner cells, a command neuron that organizes tail-flip escape responses, undergoes potentiation of their mixed (electrical and chemical) synapses in response to high frequency cellular activity. This property is likely to represent a mechanism of input sensitization as these neurons provide the Mauthner cell with essential information for the initiation of an escape response. We review here the anatomical and physiological specializations of these identifiable auditory afferents. In particular, we discuss how their membrane and synaptic properties act in concert to more efficaciously activate the Mauthner cells. The striking functional specializations of these neurons suggest that primary auditory afferents might be capable of more sophisticated contributions to auditory processing than has been generally recognized. PMID:19941953

  8. Genetic and pharmacological evidence for low-abundance TRPV3 expression in primary vagal afferent neurons.

    PubMed

    Wu, Shaw-Wen; Lindberg, Jonathan E M; Peters, James H

    2016-05-01

    Primary vagal afferent neurons express a multitude of thermosensitive ion channels. Within this family of ion channels, the heat-sensitive capsaicin receptor (TRPV1) greatly influences vagal afferent signaling by determining the threshold for action-potential initiation at the peripheral endings, while controlling temperature-sensitive forms of glutamate release at central vagal terminals. Genetic deletion of TRPV1 does not completely eliminate these temperature-dependent effects, suggesting involvement of additional thermosensitive ion channels. The warm-sensitive, calcium-permeable, ion channel TRPV3 is commonly expressed with TRPV1; however, the extent to which TRPV3 is found in vagal afferent neurons is unknown. Here, we begin to characterize the genetic and functional expression of TRPV3 in vagal afferent neurons using molecular biology (RT-PCR and RT-quantitative PCR) in whole nodose and isolated neurons and fluorescent calcium imaging on primary cultures of nodose ganglia neurons. We confirmed low-level TRPV3 expression in vagal afferent neurons and observed direct activation with putative TRPV3 agonists eugenol, ethyl vanillin (EVA), and farnesyl pyrophosphate (FPP). Agonist activation stimulated neurons also containing TRPV1 and was blocked by ruthenium red. FPP sensitivity overlapped with EVA and eugenol but represented the smallest percentage of vagal afferent neurons, and it was the only agonist that did not stimulate neurons from TRPV3(-/-1) mice, suggesting FPP has the highest selectivity. Further, FPP was predictive of enhanced responses to capsaicin, EVA, and eugenol in rats. From our results, we conclude TRPV3 is expressed in a discrete subpopulation of vagal afferent neurons and may contribute to vagal afferent signaling either directly or in combination with TRPV1. PMID:26843581

  9. External QX-314 inhibits evoked cranial primary afferent synaptic transmission independent of TRPV1.

    PubMed

    Hofmann, Mackenzie E; Largent-Milnes, Tally M; Fawley, Jessica A; Andresen, Michael C

    2014-12-01

    The cell-impermeant lidocaine derivative QX-314 blocks sodium channels via intracellular mechanisms. In somatosensory nociceptive neurons, open transient receptor potential vanilloid type 1 (TRPV1) receptors provide a transmembrane passageway for QX-314 to produce long-lasting analgesia. Many cranial primary afferents express TRPV1 at synapses on neurons in the nucleus of the solitary tract and caudal trigeminal nucleus (Vc). Here, we investigated whether QX-314 interrupts neurotransmission from primary afferents in rat brain-stem slices. Shocks to the solitary tract (ST) activated highly synchronous evoked excitatory postsynaptic currents (ST-EPSCs). Application of 300 μM QX-314 increased the ST-EPSC latency from TRPV1+ ST afferents, but, surprisingly, it had similar actions at TRPV1- ST afferents. Continued exposure to QX-314 blocked evoked ST-EPSCs at both afferent types. Neither the time to onset of latency changes nor the time to ST-EPSC failure differed between responses for TRPV1+ and TRPV1- inputs. Likewise, the TRPV1 antagonist capsazepine failed to prevent the actions of QX-314. Whereas QX-314 blocked ST-evoked release, the frequency and amplitude of spontaneous EPSCs remained unaltered. In neurons exposed to QX-314, intracellular current injection evoked action potentials suggesting a presynaptic site of action. QX-314 acted similarly at Vc neurons to increase latency and block EPSCs evoked from trigeminal tract afferents. Our results demonstrate that QX-314 blocked nerve conduction in cranial primary afferents without interrupting the glutamate release mechanism or generation of postsynaptic action potentials. The TRPV1 independence suggests that QX-314 either acted extracellularly or more likely entered these axons through an undetermined pathway common to all cranial primary afferents. PMID:25185814

  10. Influence of map scale on primary afferent terminal field geometry in cat dorsal horn.

    PubMed

    Millecchia, R J; Pubols, L M; Sonty, R V; Culberson, J L; Gladfelter, W E; Brown, P B

    1991-09-01

    1. Thirty-one physiologically identified primary afferent fibers were labeled intracellularly with horseradish peroxidase (HRP). 2. A computer analysis was used to determine whether the distribution of cutaneous mechanoreceptive afferent terminals varies as a function of location within the dorsal horn somatotopic map. 3. An analysis of the geometry of the projections of these afferents has shown that 1) terminal arbors have a greater mediolateral width within the region of the foot representation than lateral to it, 2) terminal arbors have larger length-to-width ratios outside the foot representation than within it, and 3) the orientation of terminal arbors near the boundary of the foot representation reflects the angle of the boundary. Previous attribution of mediolateral width variations to primary afferent type are probably in error, although there appear to be genuine variations of longitudinal extent as a function of primary afferent type. 4. Nonuniform terminal distributions represent the first of a three-component process underlying assembly of the monosynaptic portions of cell receptive fields (RFs) and the somatotopic map. The other two components consist of the elaboration of cell dendritic trees and the establishment of selective connections. 5. The variation of primary afferent terminal distributions with map location is not an absolute requirement for development of the map; for example, the RFs of postsynaptic cells could be assembled with the use of a uniform terminal distribution for all afferents, everywhere in the map, as long as cell dendrites penetrate the appropriate portions of the presynaptic neuropil and receive connections only from afferent axons contributing to their RFs.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1753281

  11. Altered colorectal afferent function associated with TNBS-induced visceral hypersensitivity in mice

    PubMed Central

    La, Jun-Ho; Tanaka, Takahiro; Schwartz, Erica S.; McMurray, Timothy P.; Gebhart, G. F.

    2012-01-01

    Inflammation of the distal bowel is often associated with abdominal pain and hypersensitivity, but whether and which colorectal afferents contribute to the hypersensitivity is unknown. Using a mouse model of 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis, we investigated colorectal hypersensitivity following intracolonic TNBS and associated changes in colorectum and afferent functions. C57BL/6 mice were treated intracolonically with TNBS or saline. Visceromotor responses to colorectal distension (15–60 mmHg) were recorded over 8 wk in TNBS- and saline-treated (control) mice. In other mice treated with TNBS or saline, colorectal inflammation was assessed by myeloperoxidase assay and immunohistological staining. In vitro single-fiber recordings were conducted on both TNBS and saline-treated mice to assess colorectal afferent function. Mice exhibited significant colorectal hypersensitivity through day 14 after TNBS treatment that resolved by day 28 with no resensitization through day 56. TNBS induced a neutrophil- and macrophage-based colorectal inflammation as well as loss of nerve fibers, all of which resolved by days 14–28. Single-fiber recordings revealed a net increase in afferent drive from stretch-sensitive colorectal afferents at day 14 post-TNBS and reduced proportions of mechanically insensitive afferents (MIAs) at days 14–28. Intracolonic TNBS-induced colorectal inflammation was associated with the development and recovery of hypersensitivity in mice, which correlated with a transient increase and recovery of sensitization of stretch-sensitive colorectal afferents and MIAs. These results indicate that the development and maintenance of colorectal hypersensitivity following inflammation are mediated by peripheral drive from stretch-sensitive colorectal afferents and a potential contribution from MIAs. PMID:22859364

  12. Activation of guanylate cyclase-C attenuates stretch responses and sensitization of mouse colorectal afferents

    PubMed Central

    Feng, Bin; Kiyatkin, Michael E.; La, Jun-Ho; Ge, Pei; Solinga, Robert; Silos-Santiago, Inmaculada; Gebhart, G.F.

    2013-01-01

    Irritable bowel syndrome (IBS) is characterized by altered bowel habits, persistent pain and discomfort, and typically colorectal hypersensitivity. Linaclotide, a peripherally-restricted 14-amino acid peptide approved for the treatment of IBS with constipation, relieves constipation and reduces IBS-associated pain in these patients presumably by activation of guanylate cyclase-C (GC-C), which stimulates production and release of cyclic guanosine monophosphate (cGMP) from intestinal epithelial cells. We investigated whether activation of GC-C by the endogenous agonist uroguanylin or the primary downstream effector of that activation, cGMP, directly modulates responses and sensitization of mechanosensitive colorectal primary afferents. The distal 2 cm of mouse colorectum with attached pelvic nerve was harvested, pinned flat mucosal side up for in vitro single-fiber recordings and the encoding properties of mechanosensitive afferents (serosal, mucosal, muscular and muscular-mucosal) to probing and circumferential stretch studied. Both cGMP (10–300μM) and uroguanylin (1–1000nM) applied directly to colorectal receptive endings significantly reduced responses of muscular and muscular-mucosal afferents to stretch; serosal and mucosal afferents were not affected. Sensitized responses (i.e., increased responses to stretch) of muscular and muscular-mucosal afferents were reversed by cGMP, returning responses to stretch to control. Blocking the transport of cGMP from colorectal epithelia by probenecid, a mechanism validated by studies in cultured intestinal T84 cells, abolished the inhibitory effect of uroguanylin on muscular-mucosal afferents. These results suggest that GC-C agonists like linaclotide alleviate colorectal pain and hypersensitivity by dampening stretch-sensitive afferent mechanosensitivity and normalizing afferent sensitization. PMID:23739979

  13. Enhanced sympathetic activity and cardiac sympathetic afferent reflex in rats with heart failure induced by adriamycin.

    PubMed

    Zhang, Shujuan; Zhang, Feng; Sun, Haijian; Zhou, Yebo; Han, Ying

    2012-11-01

    Our previous studies have shown that the cardiac sympathetic afferent reflex is enhanced in rats with chronic heart failure (CHF) induced by coronary artery ligation and contributes to the over-excitation of sympathetic activity. We sought to determine whether sympathetic activity and cardiac sympathetic afferent reflex were enhanced in adriamycin-induced CHF and whether angiotensin II (Ang II) in the paraventricular nucleus (PVN) was involved in enhancing sympathetic activity and cardiac sympathetic afferent reflex. Heart failure was induced by intraperitoneal injection of adriamycin for six times during 2 weeks (15 mg/kg). Six weeks after the first injection, the rats underwent anesthesia with urethane and α-chloralose. After vagotomy and baroreceptor denervation, cardiac sympathetic afferent reflex was evaluated by renal sympathetic nerve activity and mean arterial pressure (MAP) response to epicardial application of capsaicin (1.0 nmol). The response of MAP to ganglionic blockade with hexamethonium in conscious rats was performed to evaluate sympathetic activity. The renal sympathetic nerve activity and cardiac sympathetic afferent reflex were enhanced in adriamycin rats and the maximum depressor response of MAP induced by hexamethonium was significantly greater in adriamycin rats than that in control rats. Bilateral PVN microinjection of angiotensin II (Ang II) caused larger responses of the cardiac sympathetic afferent reflex, baseline renal sympathetic nerve activity and MAP in adriamycin rats than control rats. These results indicated that both sympathetic activity and cardiac sympathetic afferent reflex were enhanced and Ang II in the PVN was involved in the enhanced sympathetic activity and cardiac sympathetic afferent reflex in rats with adriamycin-induced heart failure. PMID:23554781

  14. Enhanced sympathetic activity and cardiac sympathetic afferent reflex in rats with heart failure induced by adriamycin

    PubMed Central

    Zhang, Shujuan; Zhang, Feng; Sun, Haijian; Zhou, Yebo; Han, Ying

    2012-01-01

    Our previous studies have shown that the cardiac sympathetic afferent reflex is enhanced in rats with chronic heart failure (CHF) induced by coronary artery ligation and contributes to the over-excitation of sympathetic activity. We sought to determine whether sympathetic activity and cardiac sympathetic afferent reflex were enhanced in adriamycin-induced CHF and whether angiotensin II (Ang II) in the paraventricular nucleus (PVN) was involved in enhancing sympathetic activity and cardiac sympathetic afferent reflex. Heart failure was induced by intraperitoneal injection of adriamycin for six times during 2 weeks (15 mg/kg). Six weeks after the first injection, the rats underwent anesthesia with urethane and α-chloralose. After vagotomy and baroreceptor denervation, cardiac sympathetic afferent reflex was evaluated by renal sympathetic nerve activity and mean arterial pressure (MAP) response to epicardial application of capsaicin (1.0 nmol). The response of MAP to ganglionic blockade with hexamethonium in conscious rats was performed to evaluate sympathetic activity. The renal sympathetic nerve activity and cardiac sympathetic afferent reflex were enhanced in adriamycin rats and the maximum depressor response of MAP induced by hexamethonium was significantly greater in adriamycin rats than that in control rats. Bilateral PVN microinjection of angiotensin II (Ang II) caused larger responses of the cardiac sympathetic afferent reflex, baseline renal sympathetic nerve activity and MAP in adriamycin rats than control rats. These results indicated that both sympathetic activity and cardiac sympathetic afferent reflex were enhanced and Ang II in the PVN was involved in the enhanced sympathetic activity and cardiac sympathetic afferent reflex in rats with adriamycin-induced heart failure. PMID:23554781

  15. External QX-314 inhibits evoked cranial primary afferent synaptic transmission independent of TRPV1

    PubMed Central

    Largent-Milnes, Tally M.; Fawley, Jessica A.; Andresen, Michael C.

    2014-01-01

    The cell-impermeant lidocaine derivative QX-314 blocks sodium channels via intracellular mechanisms. In somatosensory nociceptive neurons, open transient receptor potential vanilloid type 1 (TRPV1) receptors provide a transmembrane passageway for QX-314 to produce long-lasting analgesia. Many cranial primary afferents express TRPV1 at synapses on neurons in the nucleus of the solitary tract and caudal trigeminal nucleus (Vc). Here, we investigated whether QX-314 interrupts neurotransmission from primary afferents in rat brain-stem slices. Shocks to the solitary tract (ST) activated highly synchronous evoked excitatory postsynaptic currents (ST-EPSCs). Application of 300 μM QX-314 increased the ST-EPSC latency from TRPV1+ ST afferents, but, surprisingly, it had similar actions at TRPV1− ST afferents. Continued exposure to QX-314 blocked evoked ST-EPSCs at both afferent types. Neither the time to onset of latency changes nor the time to ST-EPSC failure differed between responses for TRPV1+ and TRPV1− inputs. Likewise, the TRPV1 antagonist capsazepine failed to prevent the actions of QX-314. Whereas QX-314 blocked ST-evoked release, the frequency and amplitude of spontaneous EPSCs remained unaltered. In neurons exposed to QX-314, intracellular current injection evoked action potentials suggesting a presynaptic site of action. QX-314 acted similarly at Vc neurons to increase latency and block EPSCs evoked from trigeminal tract afferents. Our results demonstrate that QX-314 blocked nerve conduction in cranial primary afferents without interrupting the glutamate release mechanism or generation of postsynaptic action potentials. The TRPV1 independence suggests that QX-314 either acted extracellularly or more likely entered these axons through an undetermined pathway common to all cranial primary afferents. PMID:25185814

  16. Miniature tilting pad gas lubricated bearing

    SciTech Connect

    Sixsmith, H.; Swift, W.L.

    1983-12-01

    This paper describes the design and development of a miniature tilting pad gas bearing developed for use in very small turbomachines. The bearings have been developed for cryogenic turboexpanders with shaft diameters down to about 0.3 cm and rotational speeds up to one million rpm. Cryogenic expansion turbines incorporating this type of bearing should be suitable for refrigeration rates down to about 10 w.

  17. A miniature tilting pad gas lubricated bearing

    NASA Astrophysics Data System (ADS)

    Sixsmith, H.; Swift, W. L.

    1983-12-01

    This paper describes the design and development of a miniature tilting pad gas bearing developed for use in very small turbomachines. The bearings have been developed for cryogenic turboexpanders with shaft diameters down to about 0.3 cm and rotational speeds up to one million rpm. Cryogenic expansion turbines incorporating this type of bearing should be suitable for refrigeration rates down to about 10 w.

  18. A miniature tilting pad gas lubricated bearing

    NASA Technical Reports Server (NTRS)

    Sixsmith, H.; Swift, W. L.

    1983-01-01

    This paper describes the design and development of a miniature tilting pad gas bearing developed for use in very small turbomachines. The bearings have been developed for cryogenic turboexpanders with shaft diameters down to about 0.3 cm and rotational speeds up to one million rpm. Cryogenic expansion turbines incorporating this type of bearing should be suitable for refrigeration rates down to about 10 w.

  19. Afference copy as a quantitative neurophysiological model for consciousness.

    PubMed

    Cornelis, Hugo; Coop, Allan D

    2014-06-01

    Consciousness is a topic of considerable human curiosity with a long history of philosophical analysis and debate. We consider there is nothing particularly complicated about consciousness when viewed as a necessary process of the vertebrate nervous system. Here, we propose a physiological "explanatory gap" is created during each present moment by the temporal requirements of neuronal activity. The gap extends from the time exteroceptive and proprioceptive stimuli activate the nervous system until they emerge into consciousness. During this "moment", it is impossible for an organism to have any conscious knowledge of the ongoing evolution of its environment. In our schematic model, a mechanism of "afference copy" is employed to bridge the explanatory gap with consciously experienced percepts. These percepts are fabricated from the conjunction of the cumulative memory of previous relevant experience and the given stimuli. They are structured to provide the best possible prediction of the expected content of subjective conscious experience likely to occur during the period of the gap. The model is based on the proposition that the neural circuitry necessary to support consciousness is a product of sub/preconscious reflexive learning and recall processes. Based on a review of various psychological and neurophysiological findings, we develop a framework which contextualizes the model and briefly discuss further implications. PMID:25012715

  20. State-space decoding of primary afferent neuron firing rates

    NASA Astrophysics Data System (ADS)

    Wagenaar, J. B.; Ventura, V.; Weber, D. J.

    2011-02-01

    Kinematic state feedback is important for neuroprostheses to generate stable and adaptive movements of an extremity. State information, represented in the firing rates of populations of primary afferent (PA) neurons, can be recorded at the level of the dorsal root ganglia (DRG). Previous work in cats showed the feasibility of using DRG recordings to predict the kinematic state of the hind limb using reverse regression. Although accurate decoding results were attained, reverse regression does not make efficient use of the information embedded in the firing rates of the neural population. In this paper, we present decoding results based on state-space modeling, and show that it is a more principled and more efficient method for decoding the firing rates in an ensemble of PA neurons. In particular, we show that we can extract confounded information from neurons that respond to multiple kinematic parameters, and that including velocity components in the firing rate models significantly increases the accuracy of the decoded trajectory. We show that, on average, state-space decoding is twice as efficient as reverse regression for decoding joint and endpoint kinematics.

  1. Control of arousal through neuropeptide afferents of the locus coeruleus.

    PubMed

    Zitnik, Gerard A

    2016-06-15

    The locus coeruleus-norepinephine (LC-NE) system is implicated in mediating several aspects of arousal. Alterations in LC neuronal discharge is associated with distinct changes in behavior, cognition, sensory processing and regulation of the sleep-wake cycle. Changes in LC output and subsequent release of NE in target brain regions help adjust arousal state to respond appropriately to environmental conditions and behavioral circumstances. One way in which LC activity is controlled is through release of endogenous neuropeptides. Based on the sleep-wake cycle and environmental cues specific neuropeptide afferent systems are activated, innervating the LC. These neuropeptides include: corticotropin releasing factor (CRF), orexin (ORX), endogenous opioids, substance P (SP), melanin-concentrating hormone (MCH), neuropeptide Y (NPY) and somatostatin (SS). This review summarizes studies examining the neuroanatomical projections of these neuropeptides, their receptors in the LC, the actions on LC neurons and downstream NE release, as well as the behavioral and cognitive effects associated individual neuropeptide-mediated innervation of the LC. Finally, the relationship between individual neuropeptides, the LC-NE system and various clinical disorders is discussed, providing evidence for possible therapeutic targets for treatment of several arousal- and stress-related disorders. This article is part of a Special Issue entitled SI: Noradrenergic System. PMID:26688115

  2. Inflammation of the infrapatellar fat pad.

    PubMed

    Eymard, Florent; Chevalier, Xavier

    2016-07-01

    The infrapatellar fat pad (IFP) of Hoffa's fat pad is the main adipose structure within the knee joint. It is located between the joint capsule and the synovial membrane, which lines its posterior aspect. The IFP is composed chiefly of adipocytes and receives an abundant supply of blood vessels and nerves. Immune cells can infiltrate the IFP, which can become a major source of numerous proinflammatory mediators (cytokines and adipokines). The physiological role for the IFP remains unclear but may involve shock absorption and the protection of adjacent tissues. Hoffa's disease is characterized by inflammation, hypertrophy, and fibrosis of the pad in response to repetitive trauma. Anterior knee pain is the most common symptom. In advanced forms, metaplasia of the IFP may result in the development of a sometimes sizable osteochondroma. The IFP may also contribute to the pathophysiology of knee osteoarthritis, in particular via procatabolic and proinflammatory effects on its synovial lining. Finally, in patients with knee osteoarthritis, inflammation of the IFP may be a source of pain. PMID:27068617

  3. Coarse topographic organization of pheromone-sensitive afferents from different antennal surfaces in the American cockroach.

    PubMed

    Nishino, Hiroshi; Watanabe, Hidehiro; Kamimura, Itsuro; Yokohari, Fumio; Mizunami, Makoto

    2015-05-19

    In contrast to visual, auditory, taste, and mechanosensory neuropils, in which sensory afferents are topographically organized on the basis of their peripheral soma locations, axons of cognate sensory neurons from different locations of the olfactory sense organ converge onto a small spherical neuropil (glomerulus) in the first-order olfactory center. In the cockroach Periplaneta americana, sex pheromone-sensitive afferents with somata in the antero-dorsal and postero-ventral surfaces of a long whip-like antenna are biased toward the anterior and posterior regions of a macroglomerulus, respectively. In each region, afferents with somata in the more proximal antenna project to more proximal region, relative to the axonal entry points. However, precise topography of afferents in the macroglomerulus has remained unknown. Using single and multiple neuronal stainings, we showed that afferents arising from anterior, dorsal, ventral and posterior surfaces of the proximal regions of an antenna were biased progressively from the anterior to posterior region of the macroglomerulus, reflecting chiasmatic axonal re-arrangements that occur immediately before entering the antennal lobe. Morphologies of individual afferents originating from the proximal antenna matched results of mass neuronal stainings, but their three-dimensional origins in the antenna were hardly predictable on the basis of the projection patterns. Such projection biases made by neuronal populations differ from strict somatotopic projections of antennal mechanosensory neurons in the same species, suggesting a unique sensory mechanism to process information about odor location and direction on a single antenna. PMID:25849528

  4. The role of the renal afferent and efferent nerve fibers in heart failure

    PubMed Central

    Booth, Lindsea C.; May, Clive N.; Yao, Song T.

    2015-01-01

    Renal nerves contain afferent, sensory and efferent, sympathetic nerve fibers. In heart failure (HF) there is an increase in renal sympathetic nerve activity (RSNA), which can lead to renal vasoconstriction, increased renin release and sodium retention. These changes are thought to contribute to renal dysfunction, which is predictive of poor outcome in patients with HF. In contrast, the role of the renal afferent nerves remains largely unexplored in HF. This is somewhat surprising as there are multiple triggers in HF that have the potential to increase afferent nerve activity, including increased venous pressure and reduced kidney perfusion. Some of the few studies investigating renal afferents in HF have suggested that at least the sympatho-inhibitory reno-renal reflex is blunted. In experimentally induced HF, renal denervation, both surgical and catheter-based, has been associated with some improvements in renal and cardiac function. It remains unknown whether the effects are due to removal of the efferent renal nerve fibers or afferent renal nerve fibers, or a combination of both. Here, we review the effects of HF on renal efferent and afferent nerve function and critically assess the latest evidence supporting renal denervation as a potential treatment in HF. PMID:26483699

  5. Information analysis of posterior canal afferents in the turtle, Trachemys scripta elegans

    PubMed Central

    Rowe, Michael H.; Neiman, Alexander B.

    2011-01-01

    We have used sinusoidal and band limited Gaussian noise stimuli along with information measures to characterize the linear and non-linear responses of morpho-physiologically identified posterior canal (PC) afferents and to examine the relationship between mutual information rate and other physiological parameters Our major findings are: 1) spike generation in most PC afferents is effectively a stochastic renewal process, and spontaneous discharges are fully characterized by their first order statistics; 2) a regular discharge, as measured by normalized coefficient of variation (cv*), reduces intrinsic noise in afferent discharges at frequencies below the mean firing rate; 3) coherence and mutual information rates, calculated from responses to band limited Gaussian noise, are jointly determined by gain and intrinsic noise (discharge regularity), the two major determinants of signal to noise ratio in the afferent response; 4) measures of optimal non-linear encoding were only moderately greater than optimal linear encoding, indicating that linear stimulus encoding is limited primarily by internal noise rather than by non-linearities; 5) a leaky integrate and fire model reproduces these results and supports the suggestion that the combination of high discharge regularity and high discharge rates serves to extend the linear encoding range of afferents to higher frequencies. These results provide a framework for future assessments of afferent encoding of signals generated during natural head movements and for comparison with coding strategies used by other sensory systems. PMID:21890114

  6. Blockade of B2 receptors attenuates the responses of group III afferents to static contraction.

    PubMed

    Leal, Anna K; Stone, Audrey J; Yamauchi, Katsuya; McCord, Jennifer L; Kaufman, Marc P

    2013-10-25

    Recent evidence has been presented demonstrating that group III mechanoreceptors comprise an important part of the sensory arm of the exercise pressor reflex, which in turn functions to increase arterial blood flow to contracting skeletal muscles. Although group III afferents are stimulated by mechanical distortion of their receptive fields, they are also stimulated by bradykinin, which is produced by skeletal muscle when it contracts. Moreover, blockade of B (bradykinin)2 receptors has been shown to decrease the magnitude of the exercise pressor reflex. Nevertheless, the effect of blockade of B2 receptors on responses of group III afferents to contraction is not known. We therefore determined the effect of B2 receptor blockade with HOE 140 (40μg/kg) on the responses to both static and intermittent contraction of group III afferents with endings in the triceps surae muscle of decerebrated unanesthetized cats. We found that HOE 140 significantly attenuated (P=0.04) the responses of 14 group III afferents to static contraction, but did not significantly attenuate (P=0.16) the responses of 16 group III afferents to intermittent contraction. The attenuation induced by HOE 140 was present throughout the static contraction period, and led us to speculate that blockade of B2 receptors on the endings of group III afferents decreased their sensitivity to mechanical events occurring in the working muscles. PMID:24036460

  7. Inflammation-induced plasticity of the afferent innervation of the airways.

    PubMed Central

    Carr, M J; Undem, B J

    2001-01-01

    The activation of primary afferent neurons that innervate the airways leads to homeostatic and defensive reflexes. The anatomic and physiologic characteristics of these afferent fibers do not appear to be static properties but rather appear to change rapidly in response to inflammation. The threshold for activation of airway afferent neurons to various stimuli, for example, is not fixed; these fibers can be become sensitized during inflammation. A subset of nociceptive-like (C-fibers) airway afferent neurons not only participates in centrally mediated reflexes but is also thought to release neuropeptides at their peripheral terminals, leading to neurogenic inflammation. An increase in the content of tachykinins is commonly seen in inflamed tissues, and there is accumulating evidence that irritation and inflammation of the airways is associated with the induction of tachykinin synthesis in non-nociceptive airway afferent fibers that under normal conditions do not contain neuropeptides. The release of neurokinins from the peripheral terminals in the airways and their central terminals in the brain stem may contribute to the symptoms of inflammatory airway diseases. Elevated release of neurokinins from peripheral terminals may promote local inflammatory responses, and the release of neurokinins in the brainstem, together with inflammation-induced increases in the excitability of afferent fibers, may culminate in altered visceral autonomic reflex activity, changes in breathing pattern, and cough. PMID:11544165

  8. Effects of gastric distension and infusion of umami and bitter taste stimuli on vagal afferent activity.

    PubMed

    Horn, Charles C; Murat, Chloé; Rosazza, Matthew; Still, Liz

    2011-10-24

    Until recently, sensory nerve pathways from the stomach to the brain were thought to detect distension and play little role in nutritional signaling. Newer data have challenged this view, including reports on the presence of taste receptors in the gastrointestinal lumen and the stimulation of multi-unit vagal afferent activity by glutamate infusions into the stomach. However, assessing these chemosensory effects is difficult because gastric infusions typically evoke a distension-related vagal afferent response. In the current study, we recorded gastric vagal afferent activity in the rat to investigate the possibility that umami (glutamate, 150 mM) and bitter (denatonium, 10 mM) responses could be dissociated from distension responses by adjusting the infusion rate and opening or closing the drainage port in the stomach. Slow infusions of saline (5 ml over 2 min, open port) produced no significant effects on vagal activity. Using the same infusion rate, glutamate or denatonium solutions produced little or no effects on vagal afferent activity. In an attempt to reproduce a prior report that showed distention and glutamate responses, we produced a distension response by closing the exit port. Under this condition, response to the infusion of glutamate or denatonium was similar to saline. In summary, we found little or no effect of gastric infusion of glutamate or denatonium on gastric vagal afferent activity that could be distinguished from distension responses. The current results suggest that sensitivity to umami or bitter stimuli is not a common property of gastric vagal afferent fibers. PMID:21925651

  9. Methods and apparatus for using gas and liquid phase cathodic depolarizers

    NASA Technical Reports Server (NTRS)

    Murphy, Oliver J. (Inventor); Hitchens, G. Duncan (Inventor)

    1998-01-01

    The invention provides methods for using gas and liquid phase cathodic depolarizers in an electrochemical cell having a cation exchange membrane in intimate contact with the anode and cathode. The electrochemical conversion of cathodic depolarizers at the cathode lowers the cell potential necessary to achieve a desired electrochemical conversion, such as ozone evolution, at the anode. When gaseous cathodic depolarizers, such as oxygen, are used, a gas diffusion cathode having the cation exchange membrane bonded thereto is preferred. When liquid phase cathodic depolarizers are used, the cathode may be a flow-by electrode, flow-through electrode, packed-bed electrode or a fluidized-bed electrode in intimate contact with the cation exchange membrane.

  10. De-polarization of a CdZnTe radiation detector by pulsed infrared light

    SciTech Connect

    Dědič, V. Franc, J.; Rejhon, M.; Grill, R.; Zázvorka, J.; Sellin, P. J.

    2015-07-20

    This work is focused on a detailed study of pulsed mode infrared light induced depolarization of CdZnTe detectors operating at high photon fluxes. This depolarizing effect is a result of the decrease of positive space charge that is caused by the trapping of photogenerated holes at a deep level. The reduction in positive space charge is due to the optical transition of electrons from a valence band to the deep level due to additional infrared illumination. In this paper, we present the results of pulse mode infrared depolarization, by which it is possible to keep the detector in the depolarized state during its operation. The demonstrated mechanism represents a promising way to increase the charge collection efficiency of CdZnTe X-ray detectors operating at high photon fluxes.

  11. Aerosol Properties over Southeastern China from Multi-Wavelength Raman and Depolarization Lidar Measurements

    NASA Astrophysics Data System (ADS)

    Heese, Birgit; Althausen, Dietrich; Baars, Holger; Bohlmann, Stephanie; Deng, Ruru

    2016-06-01

    A dataset of particle optical properties of highly polluted urban aerosol over the Pearl River Delta, Guangzhou, China is presented. The data were derived from multi-wavelengths Raman and depolarization lidar PollyXT and AERONET sun photometer measurements. The measurement campaign was conducted from Nov 2011 to June 2012. High aerosol optical depth was observed in the polluted atmosphere over this megacity, with a mean value of 0.54 ± 0.33 and a peak value of even 1.9. For the particle characterization the lidar ratio and the linear particle depolarization ratio, both at 532 nm, were used. The mean values of these properties are 48.0 sr ± 10.7 sr for the lidar ratio and 4%+-4% for the particle depolarization ratio, which means most depolarization measurements stayed below 10%. So far, most of these results indicate urban pollution particles mixed with particles arisen from biomass and industrial burning.

  12. Suppression of Ultracold Neutron Depolarization on Material Surfaces with Magnetic Holding Fields

    NASA Astrophysics Data System (ADS)

    Rios, Raymond

    2009-05-01

    The depolarization of Ultracold Neutrons(UCN) was measured within 1-m long, 2 3/4" diameter electropolished copper, diamondlike carbon-coated copper, and stainless steel guide tubes as a function of magnetic holding field. The UCN were trapped between a 6 Tesla solenoidal magnetic field and a 3/8" copper aperture. A series of Helmholtz coils produced a magnetic field over the length of the test guide of either 10 or 250 Gauss. The surface depolarization was observed to be suppressed at the higher holding field on the measured copper guides. These measurements will aid in the determination of the upper limit of depolarization of UCN in the UCN beta asymmetry measurement at LANL (UCNA) and in understanding the mechanisms for depolarization in non-magnetic guides.

  13. Early depolarizing GABA controls critical period plasticity in the rat visual cortex

    PubMed Central

    Deidda, Gabriele; Allegra, Manuela; Cerri, Chiara; Naskar, Shovan; Bony, Guillaume; Zunino, Giulia; Bozzi, Yuri; Caleo, Matteo; Cancedda, Laura

    2014-01-01

    SUMMARY Hyperpolarizing and inhibitory GABA regulates “critical periods” for plasticity in sensory cortices. Here, we examine the role of early, depolarizing GABA in controlling plasticity mechanisms. We report that brief interference with depolarizing GABA during early development prolonged critical period plasticity in visual cortical circuits, without affecting overall development of the visual system. The effects on plasticity were accompanied by dampened inhibitory neurotransmission, down-regulation of BDNF expression, and reduced density of extracellular matrix-perineuronal nets. Early interference with depolarizing GABA decreased perinatal BDNF signaling, and pharmacological increase of BDNF signaling during GABA interference rescued the effects on plasticity and its regulators later in life. We conclude that depolarizing GABA exerts a long-lasting, selective modulation of plasticity of cortical circuits by a strong crosstalk with BDNF. PMID:25485756

  14. Thermally induced depolarization in terbium gallium garnet ceramics rod with natural convection cooling

    NASA Astrophysics Data System (ADS)

    Slezak, Ondrej; Yasuhara, Ryo; Lucianetti, Antonio; Vojna, David; Mocek, Tomas

    2015-06-01

    Thermal birefringence-induced depolarization in terbium gallium garnet (TGG) ceramic rods has been numerically evaluated for the geometry and heating conditions in a previous experiment. In this model, the spatially resolved heat transfer coefficient corresponding to natural convection cooling and the offset of the beam from the rotational axis of the rod have been incorporated and the realistic beam profile used in the experiment has been considered. A resulting beam depolarization ratio of 4.3 × 10-4 has been calculated for an input power of 117 W. The results were found to be in good agreement with the measured values. Furthermore, a parametric study of the depolarization ratio for higher input powers has been performed leading to a depolarization ratio of 3.3 × 10-2 for 1 kW input power.

  15. Depolarization of cell membrane is associated with an increase in ciliary beat frequency (CBF).

    PubMed

    Mao, H; Wong, L B

    1995-10-24

    We hypothesize that activation of muscarinic cholinergic receptors depolarizes the cell membrane of the mammalian ciliated cells which in turn causes an increase of CBF. To test this hypothesis, a di-8-ANEPPS fluorescence photon counting and nonstationary heterodyne laser light scattering system was developed to measure cell membrane potential (psi) and CBF in cultured ovine tracheal ciliated cells simultaneously. Carbachol dose dependently depolarized the cell membrane with a corresponding stimulation of CBF. The carbachol induced depolarization of cell membrane and increases of CBF were inhibited by prior application of either atropine or verapamil or amiloride. These novel data suggest that depolarization of the cell membrane and the corresponding stimulation of CBF caused by the activation of muscarinic receptors of the mammalian ciliated cells are dependent on the influx of either extracellular Ca2+ or Na+. PMID:7488025

  16. Purinergic 2 receptor blockade prevents the responses of group IV afferents to post-contraction circulatory occlusion

    PubMed Central

    Kindig, Angela E; Hayes, Shawn G; Kaufman, Marc P

    2007-01-01

    ATP, by activating purinergic 2 (P2) receptors on group III and IV afferents, is thought to evoke the metabolic component of the exercise pressor reflex. Previously we have shown that injection of PPADS, a P2 receptor antagonist, into the arterial supply of skeletal muscle of decerebrated cats attenuated the responses of group III and IV afferents to static contraction while the muscles were freely perfused. We have now tested the hypothesis that injection of PPADS (10 mg kg−1) attenuated the responses of group III (n = 13) and group IV afferents (n = 9) to post-contraction circulatory occlusion. In the present study, we found that PPADS attenuated the group III afferent responses to static contraction during circulatory occlusion (P < 0.05). Likewise, PPADS abolished the group IV afferent responses to static contraction during occlusion (P = 0.001). During a 1 minute period of post-contraction circulatory occlusion, four of the 13 group III afferents and eight of the nine group IV afferents maintained their increased discharge. A Fischer's exact probability test revealed that more group IV afferents than group III afferents were stimulated by post-contraction circulatory occlusion (P < 0.02). In addition, the nine group IV afferents increased their mean discharge rate over baseline levels during the post-contraction circulatory occlusion period, whereas the 13 group III afferents did not (P < 0.05). PPADS abolished this post-contraction increase in discharge by the group IV afferents (P < 0.05). Our findings suggest that P2 receptors on group IV afferents play a role in evoking the metabolic component of the exercise pressor reflex. PMID:17038431

  17. Three-Signal Method for Accurate Measurements of Depolarization Ratio with Lidar

    NASA Technical Reports Server (NTRS)

    Reichardt, Jens; Baumgart, Rudolf; McGee, Thomsa J.

    2003-01-01

    A method is presented that permits the determination of atmospheric depolarization-ratio profiles from three elastic-backscatter lidar signals with different sensitivity to the state of polarization of the backscattered light. The three-signal method is insensitive to experimental errors and does not require calibration of the measurement, which could cause large systematic uncertainties of the results, as is the case in the lidar technique conventionally used for the observation of depolarization ratios.

  18. A review of depolarization modeling for earth-space radio paths at frequencies above 10 GHz

    NASA Technical Reports Server (NTRS)

    Bostian, C. W.; Stutzman, W. L.; Gaines, J. M.

    1982-01-01

    A review is presented of models for the depolarization, caused by scattering from raindrops and ice crystals, that limits the performance of dual-polarized satellite communication systems at frequencies above 10 GHz. The physical mechanisms of depolarization as well as theoretical formulations and empirical data are examined. Three theoretical models, the transmission, attenuation-derived, and scaling models, are described and their relative merits are considered.

  19. Control of cyclic adenosine 3',5'-monophosphate levels by depolarizing agents in fungi.

    PubMed Central

    Trevillyan, J M; Pall, M L

    1979-01-01

    It has been reported that diverse treatments which depolarize the plasma membrane of Neurospora crassa produce rapid increases in cyclic adenosine 3',5'-monophosphate (cyclic AMP) levels. In the current study, membrane active antibiotics, which are known or putative depolarizing agents, were found to produce similar cyclic AMP increases, not only in N. crassa, but also in the distantly related fungi Saccharomyces cerevisiae and Mucor racemosus. Uncouplers of oxidative phosphorylation, which have been found to depolarize Neurospora, also produced cyclic AMP increases in all three fungi. The time course of the cyclic AMP response to these various treatments was similar in all three fungi. The fungal studies and studies on depolarized central nervous tissue suggest that cyclic AMP increases may be produced in response to plasma membrane depolarization in diverse eucaryotic cells. A model is proposed for eucaryotic microorganisms in which membrane depolarization serves as a signal of breakdown of the plasma membrane integrity. The subsequent cyclic AMP increase, in turn, may mediate cellular response to help protect the plasma membrane from chemical and mechanical threats to its integrity. PMID:220213

  20. Depolarization of synchrotron radiation in a multilayer magneto-ionic medium

    NASA Astrophysics Data System (ADS)

    Shneider, C.; Haverkorn, M.; Fletcher, A.; Shukurov, A.

    2014-07-01

    Depolarization of diffuse radio synchrotron emission is classified in terms of wavelength-independent and wavelength-dependent depolarization in the context of regular magnetic fields and of both isotropic and anisotropic turbulent magnetic fields. Previous analytical formulas for depolarization due to differential Faraday rotation are extended to include internal Faraday dispersion concomitantly, for a multilayer synchrotron emitting and Faraday rotating magneto-ionic medium. In particular, depolarization equations for a two- and three-layer system (disk-halo, halo-disk-halo) are explicitly derived. To both serve as a "user's guide" to the theoretical machinery and as an approach for disentangling line-of-sight depolarization contributions in face-on galaxies, the analytical framework is applied to data from a small region in the face-on grand-design spiral galaxy M 51. The effectiveness of the multiwavelength observations in constraining the pool of physical depolarization scenarios is illustrated for a two- and three-layer model along with a Faraday screen system for an observationally motivated magnetic field configuration.

  1. Depolarization counteracts glucocorticoid inhibition of adenohypophysical corticotroph cells

    PubMed Central

    Lim, M C; Shipston, M J; Antoni, F A

    1998-01-01

    mM CPT-cAMP-induced ACTH secretion by 100 nM dexamethasone. In primary cultures of rat anterior pituitary cells, depolarization of the membrane potential with 40 mM KCl enhanced the ACTH response to CPT-cAMP and markedly reduced the maximal inhibitory effect of dexamethasone to 55±1.2% as well as that of corticosterone to 33±2.1% vs 100±2.5% and 100±1.9% inhibition respectively, when 0.1 mM CPT-cAMP was used alone. Introduction of 5 μM (−)BayK8644 with 40 mM KCl in this system had no additional effect on glucocorticoid inhibition. No glucocorticoid inhibition of ACTH release to any of the stimuli applied was observed in cells pretreated with the mRNA synthesis inhibitor, 5,6-dichloro-furanosyl-benzimidazole riboside (DRB) (0.1 mM) or the protein synthesis blocker, puromycin (0.1 mM). In summary, early glucocorticoid inhibition of stimulated ACTH release by cultured rat anterior pituitary cells was dependent on the synthesis of new mRNA and protein. Depolarization of the membrane potential potentiated CPT-cAMP-induced ACTH secretion in AtT20 cells as well as cultured rat corticotrophs and this was associated with a resistance to the early inhibitory effect of glucocorticoids. Glucocorticoid inhibition in rat anterior pituitary corticotrophs was unaltered by TEA, charybdotoxin as well as apamin, and hence it is unlikely to involve predominantly BK-or SK-type Ca2+-activated K+-channels. These results support the thesis that a prime target of glucocorticoid feedback inhibition in anterior pituitary corticotrophs is the membrane potential and indicate that glucocorticoid-induced proteins regulate the activities of several distinct plasma membrane ion channels. PMID:9756391

  2. Endogenous bradykinin activates ischaemically sensitive cardiac visceral afferents through kinin B2 receptors in cats

    PubMed Central

    Tjen-A-Looi, Stephanie C; Pan, Hui-Lin; Longhurst, John C

    1998-01-01

    Activity of ischaemically sensitive cardiac visceral afferents during myocardial ischaemia induces both angina and cardiovascular reflexes. Increased production of bradykinin (BK) and cyclo-oxygenase products (i.e. prostaglandins (PGs)) occurs during myocardial ischaemia. However, the role of these agents in activation of ischaemically sensitive cardiac afferents has not been established. The present study tested the hypothesis that BK produced during ischaemia activates cardiac afferents through kinin B2 receptors. Single-unit activity of cardiac afferents innervating the left ventricle was recorded from the left thoracic sympathetic chain (T1–T4) of anaesthetized cats. Ischaemically sensitive cardiac afferents were identified according to their response to 5 min of myocardial ischaemia. The mechanism of BK in activation of ischaemically sensitive cardiac afferents was determined by injection of BK (1 μg kg−1 i.a.), des-Arg9-BK (1 μg kg−1 i.a., a specific kinin B1 receptor agonist), kinin B2 receptor antagonists: HOE140 (30 μg kg−1 i.v.) and NPC-17731 (40 μg kg−1 i.v.), cyclo-oxygenase inhibition with indomethacin (5 mg kg−1 i.v.) and NPC-17731 (40 μg kg−1 i.v.) after pretreatment with indomethacin (5 mg kg−1 i.v.). We observed that BK increased the discharge rate of all eleven ischaemically sensitive cardiac afferents from 0.39 ± 0.12 to 1.47 ± 0.37 impulses s−1 (P < 0.05). Conversely, des-Arg9-BK did not significantly increase the activity of eleven ischaemically sensitive fibres (0.58 ± 0.02 vs. 0.50 ± 0.18 impulses s−1). HOE140 significantly attenuated the response of twelve afferents to ischaemia (0.61 ± 0.22 to 1.85 ± 0.5 vs. 0.53 ± 0.16 to 1.09 ± 0.4 impulses s−1). NPC-17731, another kinin B2 receptor antagonist, had similar inhibitory effects on six other ischaemically sensitive cardiac afferents (0.35 ± 0.14 to 1.19 ± 0.29 vs. 0.22 ± 0.08 to 0.23 ± 0.07 impulses s−1). Indomethacin significantly reduced the

  3. Facilitation of motor evoked potentials by somatosensory afferent stimulation.

    PubMed

    Deletis, V; Schild, J H; Berić, A; Dimitrijević, M R

    1992-10-01

    The effect of an electrically induced peripheral afferent volley upon electrical and magnetic motor evoked potentials (MEPs) from muscles of the upper and lower extremities was studied in 16 healthy volunteers. A standard conditioning-test (C-T) paradigm was employed whereby the test stimulus (transcranial electric or magnetic) was applied at random time intervals, from 10 msec prior to 90 msec after the conditioning stimulus (peripheral nerve stimulus). MEP amplitude facilitation was observed for the majority of the upper extremity muscles tested at two distinct periods, one occurring at short, and the other at long C-T intervals. This bimodal trend of MEP facilitation was found to be equally as prominent in the lower extremity muscles tested. The period of short C-T interval facilitation is consistent with modifications in the spinal excitability of the segmental motoneuron pool. On the other hand, the period of long C-T interval facilitation is suggested to be due to alterations in excitability of the motor cortex as a result of the arrival of the orthodromic sensory volley. Although most pronounced in muscles innervated by the nerve to which the conditioning stimulus was applied, this bimodal facilitatory effect was also observed in adjacent muscles not innervated by the stimulated nerve. Qualitatively, the conditioned MEPs from the upper and lower extremities responded similarly to both electrical and magnetic trans-cranial stimulation. In addition, our study demonstrates that the C-T paradigm has potential for use in the assessment of spinal and cortical sensorimotor integration by providing quantitative information which cannot be obtained through isolated assessment of sensory and/or motor pathways.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1385090

  4. Endoscopic management of afferent loop syndrome after a pylorus preserving pancreatoduodenecotomy presenting with obstructive jaundice and ascending cholangitis.

    PubMed

    Kim, Jae Kyung; Park, Chan Hyuk; Huh, Ji Hye; Park, Jeong Youp; Park, Seung Woo; Song, Si Young; Chung, Jaebock; Bang, Seungmin

    2011-09-01

    Afferent loop syndrome is a rare complication of gastrojejunostomy. Patients usually present with abdominal distention and bilious vomiting. Afferent loop syndrome in patients who have undergone a pylorus preserving pancreaticoduodenectomy can present with ascending cholangitis. This condition is related to a large volume of reflux through the biliary-enteric anastomosis and static materials with bacterial overgrowth in the afferent loop. Patients with afferent loop syndrome after pylorus preserving pancreaticoduodenectomy frequently cannot be confirmed as surgical candidates due to poor medical condition. In that situation, a non-surgical palliation should be considered. Herein, we report two patients with afferent loop syndrome presenting with obstructive jaundice and ascending cholangitis. The patients suffered from the recurrence of pancreatic cancer after pylorus preserving pancreaticoduodenectomy. The diagnosis of afferent loop syndrome was confirmed, and the patients were successfully treated by inserting an endoscopic metal stent using a colonoscopic endoscope. PMID:22741115

  5. Ventral tegmental area afferents to the prefrontal cortex maintain membrane potential 'up' states in pyramidal neurons via D(1) dopamine receptors.

    PubMed

    Lewis, B L; O'Donnell, P

    2000-12-01

    The electrophysiological nature of dopamine actions has been controversial for years, with data supporting both inhibitory and excitatory actions. In this study, we tested whether stimulation of the ventral tegmental area (VTA), the source of the dopamine innervation of the prefrontal cortex, would exert different responses depending on the membrane potential states that pyramidal neurons exhibit when recorded in vivo, and whether VTA stimulation would have a role in controlling transitions between these states. Prefrontal cortical neurons have a very negative resting membrane potential (down state) interrupted by plateau depolarizations (up state). Although the up state had been shown to be dependent on hippocampal afferents in nucleus accumbens neurons, our results indicate that neither hippocampal nor thalamic inputs are sufficient to drive up events in prefrontal cortical neurons. Electrical VTA stimulation resulted in a variety of actions, in many cases depending on the neuron membrane potential state. Trains of stimuli resembling burst firing evoked a long-lasting transition to the up state, an effect blocked by a D(1) antagonist and mimicked by chemical VTA stimulation. These results indicate that projections from the VTA to the prefrontal cortex may be involved in controlling membrane potential states that define assemblies of activable pyramidal neurons in this region. PMID:11073866

  6. Vascular Endothelial Function and Blood Pressure Regulation in Afferent Autonomic Failure

    PubMed Central

    Jelani, Qurat-ul-ain; Norcliffe-Kaufmann, Lucy; Kaufmann, Horacio

    2015-01-01

    BACKGROUND Familial dysautonomia (FD) is a rare hereditary disease characterized by loss of afferent autonomic neural fiber signaling and consequent profound impairment of arterial baroreflex function and blood pressure regulation. Whether vascular endothelial dysfunction contributes to defective vasomotor control in this form of afferent autonomic failure is not known. METHODS We assessed blood pressure response to orthostatic stress and vascular endothelial function with brachial artery reactivity testing in 34 FD subjects with afferent autonomic failure and 34 healthy control subjects. RESULTS Forty-four percent of the afferent autonomic failure subjects had uncontrolled hypertension at supine rest (median systolic blood pressure = 148mm Hg, interquartile range (IQR) = 144–155mm Hg; median diastolic blood pressure = 83mm Hg, IQR = 78–105mm Hg), and 88% had abnormal response to orthostatic stress (median decrease in systolic blood pressure after upright tilt = 48mm Hg, IQR = 29–61mm Hg). Flow-mediated brachial artery reactivity did not differ in subjects with afferent autonomic failure vs. healthy control subjects (median = 6.00%, IQR = 1.86–11.77%; vs. median = 6.27%, IQR = 4.65–9.34%; P = 0.75). In afferent autonomic failure subjects, brachial artery reactivity was not associated with resting blood pressure or the magnitude of orthostatic hypotension but was decreased in association with reduced glomerular filtration rate (r = 0.62; P < 0.001). CONCLUSIONS Brachial artery reactivity was preserved in subjects with afferent autonomic failure despite the presence of marked blood pressure dysregulation. Comorbid renal dysfunction was associated with reduced brachial artery reactivity. PMID:25128693

  7. Identification of the tracheal and laryngeal afferent neurones mediating cough in anaesthetized guinea-pigs

    PubMed Central

    Canning, Brendan J; Mazzone, Stuart B; Meeker, Sonya N; Mori, Nanako; Reynolds, Sandra M; Undem, Bradley J

    2004-01-01

    We have identified the tracheal and laryngeal afferent nerves regulating cough in anaesthetized guinea-pigs. Cough was evoked by electrical or mechanical stimulation of the tracheal or laryngeal mucosa, or by citric acid applied topically to the trachea or larynx. By contrast, neither capsaicin nor bradykinin challenges to the trachea or larynx evoked cough. Bradykinin and histamine administered intravenously also failed to evoke cough. Electrophysiological studies revealed that the majority of capsaicin-sensitive afferent neurones (both Aδ- and C-fibres) innervating the rostral trachea and larynx have their cell bodies in the jugular ganglia and project to the airways via the superior laryngeal nerves. Capsaicin-insensitive afferent neurones with cell bodies in the nodose ganglia projected to the rostral trachea and larynx via the recurrent laryngeal nerves. Severing the recurrent nerves abolished coughing evoked from the trachea and larynx whereas severing the superior laryngeal nerves was without effect on coughing. The data indicate that the tracheal and laryngeal afferent neurones regulating cough are polymodal Aδ-fibres that arise from the nodose ganglia. These afferent neurones are activated by punctate mechanical stimulation and acid but are unresponsive to capsaicin, bradykinin, smooth muscle contraction, longitudinal or transverse stretching of the airways, or distension. Comparing these physiological properties with those of intrapulmonary mechanoreceptors indicates that the afferent neurones mediating cough are quite distinct from the well-defined rapidly and slowly adapting stretch receptors innervating the airways and lungs. We propose that these airway afferent neurones represent a distinct subtype and that their primary function is regulation of the cough reflex. PMID:15004208

  8. Efferent Control of Hair Cell and Afferent Responses in the Semicircular Canals

    PubMed Central

    Boyle, Richard; Rabbitt, Richard D.; Highstein, Stephen M.

    2009-01-01

    The sensations of sound and motion generated by the inner ear are controlled by the brain through extensive centripetal innervation originating within the brain stem. In the semicircular canals, brain stem efferent neurons make synaptic contacts with mechanosensory hair cells and with the dendrites of afferent neurons. Here, we examine the relative contributions of efferent action on hair cells and afferents. Experiments were performed in vivo in the oyster toadfish, Opsanus tau. The efferent system was activated via electrical pulses to the brain stem and sensory responses to motion stimuli were quantified by simultaneous voltage recording from afferents and intracellular current- and/or voltage-clamp recordings from hair cells. Results showed synaptic inputs to both afferents and hair cells leading to relatively long-latency intracellular signaling responses: excitatory in afferents and inhibitory in hair cells. Generally, the net effect of efferent action was an increase in afferent background discharge and a simultaneous decrease in gain to angular motion stimuli. Inhibition of hair cells was likely the result of a ligand-gated opening of a major basolateral conductance. The reversal potential of the efferent-evoked current was just below the hair cell resting potential, thus resulting in a small hyperpolarization. The onset latency averaged about 90 ms and latency to peak response was 150–400 ms. Hair cell inhibition often outlasted afferent excitation and, in some cases, latched hair cells in the “off” condition for >1 s following cessation of stimulus. These features endow the animal with a powerful means to adjust the sensitivity and dynamic range of motion sensation. PMID:19571186

  9. PAR-2 elicits afferent arteriolar vasodilation by NO-dependent and NO-independent actions.

    PubMed

    Trottier, Greg; Hollenberg, Morley; Wang, Xuemei; Gui, Yu; Loutzenhiser, Kathy; Loutzenhiser, Rodger

    2002-05-01

    Proteinase-activated receptors (PARs) are a novel class of G protein-coupled receptors that respond to signals through endogenous proteinases. PAR activation involves enzymatic cleavage of the extracellular NH(2)-terminal domain and unmasking of a new NH(2) terminus, which serves as an anchored ligand to activate the receptor. At least four PAR subtypes have been identified. In the present study, we used the in vitro perfused hydronephrotic rat kidney to examine the effects of activating PAR-2 on the afferent arteriole. The synthetic peptide SLIGRL-NH(2), which corresponds to the exposed ligand sequence and selectively activates PAR-2, did not alter basal afferent arteriolar diameter but caused a concentration-dependent vasodilation (3-30 microM) of arterioles preconstricted by angiotensin II (0.1 nM). A modified peptide sequence (LSIGRL-NH(2), inactive at PAR-2) had no effect. This vasodilation was characterized by an initial transient component followed by a smaller sustained response. A similar pattern of vasodilation was seen when SLIGRL-NH(2) was administered to isolated perfused normal rat kidney. The sustained component of the PAR-2-induced afferent arteriolar vasodilation was eliminated by nitric oxide (NO) synthase inhibition (100 microM nitro-L-arginine methyl ester). In contrast, the transient vasodilation persisted under these conditions. This transient response was not observed when afferent arterioles were preconstricted with elevated KCl, suggesting involvement of an endothelium-derived hyperpolarizing factor. Finally, RT-PCR revealed the presence of PAR-2 mRNA in isolated afferent arterioles. These findings indicate that PAR-2 is expressed in the afferent arteriole and that its activation elicits afferent arteriolar vasodilation by NO-dependent and NO-independent mechanisms. PMID:11934700

  10. Functional analysis of ultra high information rates conveyed by rat vibrissal primary afferents

    PubMed Central

    Chagas, André M.; Theis, Lucas; Sengupta, Biswa; Stüttgen, Maik C.; Bethge, Matthias; Schwarz, Cornelius

    2013-01-01

    Sensory receptors determine the type and the quantity of information available for perception. Here, we quantified and characterized the information transferred by primary afferents in the rat whisker system using neural system identification. Quantification of “how much” information is conveyed by primary afferents, using the direct method (DM), a classical information theoretic tool, revealed that primary afferents transfer huge amounts of information (up to 529 bits/s). Information theoretic analysis of instantaneous spike-triggered kinematic stimulus features was used to gain functional insight on “what” is coded by primary afferents. Amongst the kinematic variables tested—position, velocity, and acceleration—primary afferent spikes encoded velocity best. The other two variables contributed to information transfer, but only if combined with velocity. We further revealed three additional characteristics that play a role in information transfer by primary afferents. Firstly, primary afferent spikes show preference for well separated multiple stimuli (i.e., well separated sets of combinations of the three instantaneous kinematic variables). Secondly, neurons are sensitive to short strips of the stimulus trajectory (up to 10 ms pre-spike time), and thirdly, they show spike patterns (precise doublet and triplet spiking). In order to deal with these complexities, we used a flexible probabilistic neuron model fitting mixtures of Gaussians to the spike triggered stimulus distributions, which quantitatively captured the contribution of the mentioned features and allowed us to achieve a full functional analysis of the total information rate indicated by the DM. We found that instantaneous position, velocity, and acceleration explained about 50% of the total information rate. Adding a 10 ms pre-spike interval of stimulus trajectory achieved 80–90%. The final 10–20% were found to be due to non-linear coding by spike bursts. PMID:24367295

  11. Withdrawal and Restoration of Central Vagal Afferents Within the Dorsal Vagal Complex Following Subdiaphragmatic Vagotomy

    PubMed Central

    Peters, James H.; Gallaher, Zachary R.; Ryu, Vitaly; Czaja, Krzysztof

    2014-01-01

    Vagotomy, a severing of the peripheral axons of the vagus nerve, has been extensively utilized to determine the role of vagal afferents in viscerosensory signaling. Vagotomy is also an unavoidable component of some bariatric surgeries. Although it is known that peripheral axons of the vagus nerve degenerate and then regenerate to a limited extent following vagotomy, very little is known about the response of central vagal afferents in the dorsal vagal complex to this type of damage. We tested the hypothesis that vagotomy results in the transient withdrawal of central vagal afferent terminals from their primary central target, the nucleus of the solitary tract (NTS). Sprague–Dawley rats underwent bilateral subdiaphragmatic vagotomy and were sacrificed 10, 30, or 60 days later. Plastic changes in vagal afferent fibers and synapses were investigated at the morphological and functional levels by using a combination of an anterograde tracer, synapse-specific markers, and patch-clamp electrophysiology in horizontal brain sections. Morphological data revealed that numbers of vagal afferent fibers and synapses in the NTS were significantly reduced 10 days following vagotomy and were restored to control levels by 30 days and 60 days, respectively. Electrophysiology revealed transient decreases in spontaneous glutamate release, glutamate release probability, and the number of primary afferent inputs. Our results demonstrate that subdiaphragmatic vagotomy triggers transient withdrawal and remodeling of central vagal afferent terminals in the NTS. The observed vagotomy-induced plasticity within this key feeding center of the brain may be partially responsible for the response of bariatric patients following gastric bypass surgery. PMID:23749657

  12. The protein arginine deiminases (PADs): Structure, Function, Inhibition, and Disease

    PubMed Central

    Bicker, Kevin L.

    2012-01-01

    The post translational modification of histones has significant effects on overall chromatin function. One such modification is citrullination, which is catalyzed by the protein arginine deiminases (PADs), a unique family of enzymes that catalyzes the hydrolysis of peptidyl-arginine to form peptidyl-citrulline on histones, fibrinogen, and other biologically relevant proteins. Overexpression and/or increased PAD activity is observed in several diseases, including rheumatoid arthritis, Alzheimer’s disease, multiple sclerosis, lupus, Parkinson’s disease, and cancer. This review discusses the important structural and mechanistic characteristics of the PADs, as well as recent investigations into the role of the PADs in increasing disease severity in RA and colitis and the importance of PAD activity in mediating neutrophil extracellular trap (NET) formation through chromatin decondensation. Lastly, efforts to develop PAD inhibitors with excellent potency, selectivity and in vivo efficacy are discussed, highlighting the most promising inhibitors. PMID:23175390

  13. Soyuz Spacecraft Transported to Launch Pad

    NASA Technical Reports Server (NTRS)

    2003-01-01

    The Soyuz TMA-3 spacecraft and its booster rocket (rear view) is shown on a rail car for transport to the launch pad where it was raised to a vertical launch position at the Baikonur Cosmodrome, Kazakhstan on October 16, 2003. Liftoff occurred on October 18th, transporting a three man crew to the International Space Station (ISS). Aboard were Michael Foale, Expedition-8 Commander and NASA science officer; Alexander Kaleri, Soyuz Commander and flight engineer, both members of the Expedition-8 crew; and European Space agency (ESA) Astronaut Pedro Duque of Spain. Photo Credit: 'NASA/Bill Ingalls'

  14. Soyuz Spacecraft Transported to Launch Pad

    NASA Technical Reports Server (NTRS)

    2003-01-01

    The Soyuz TMA-3 spacecraft and its booster rocket (front view) is shown on a rail car for transport to the launch pad where it was raised to a vertical launch position at the Baikonur Cosmodrome, Kazakhstan on October 16, 2003. Liftoff occurred on October 18th, transporting a three man crew to the International Space Station (ISS). Aboard were Michael Foale, Expedition-8 Commander and NASA science officer; Alexander Kaleri, Soyuz Commander and flight engineer, both members of the Expedition-8 crew; and European Space agency (ESA) Astronaut Pedro Duque of Spain. Photo Credit: 'NASA/Bill Ingalls'

  15. Launch Pad Coatings for Smart Corrosion Control

    NASA Technical Reports Server (NTRS)

    Calle, Luz M.; Hintze, Paul E.; Bucherl, Cori N.; Li, Wenyan; Buhrow, Jerry W.; Curran, Jerome P.; Whitten, Mary C.

    2010-01-01

    Corrosion is the degradation of a material as a result of its interaction with the environment. The environment at the KSC launch pads has been documented by ASM International (formerly American Society for Metals) as the most corrosive in the US. The 70 tons of highly corrosive hydrochloric acid that are generated by the solid rocket boosters during a launch exacerbate the corrosiveness of the environment at the pads. Numerous failures at the pads are caused by the pitting of stainless steels, rebar corrosion, and the degradation of concrete. Corrosion control of launch pad structures relies on the use of coatings selected from the qualified products list (QPL) of the NASA Standard 5008A for Protective Coating of Carbon Steel, Stainless Steel, and Aluminum on Launch Structures, Facilities, and Ground Support Equipment. This standard was developed to establish uniform engineering practices and methods and to ensure the inclusion of essential criteria in the coating of ground support equipment (GSE) and facilities used by or for NASA. This standard is applicable to GSE and facilities that support space vehicle or payload programs or projects and to critical facilities at all NASA locations worldwide. Environmental regulation changes have dramatically reduced the production, handling, use, and availability of conventional protective coatings for application to KSC launch structures and ground support equipment. Current attrition rate of qualified KSC coatings will drastically limit the number of commercial off the shelf (COTS) products available for the Constellation Program (CxP) ground operations (GO). CxP GO identified corrosion detection and control technologies as a critical, initial capability technology need for ground processing of Ares I and Ares V to meet Constellation Architecture Requirements Document (CARD) CxP 70000 operability requirements for reduced ground processing complexity, streamlined integrated testing, and operations phase affordability

  16. Metal pad instabilities in liquid metal batteries

    NASA Astrophysics Data System (ADS)

    Zikanov, Oleg

    2015-12-01

    A mechanical analogy is used to analyze the interaction between the magnetic field, electric current, and deformation of interfaces in liquid metal batteries. In the framework of a low-mode, nondissipative, linear stability model, it is found that, during charging or discharging, a sufficiently large battery is prone to instabilities of two types. One is similar to the metal pad instability known to exist in the aluminum reduction cells. Another type is new. It is related to the destabilizing effect of the Lorentz force formed by the azimuthal magnetic field induced by the base current, and the current perturbations caused by the local variations of the thickness of the electrolyte layer.

  17. Launch Pad Escape System Design (Human Spaceflight)

    NASA Technical Reports Server (NTRS)

    Maloney, Kelli

    2011-01-01

    A launch pad escape system for human spaceflight is one of those things that everyone hopes they will never need but is critical for every manned space program. Since men were first put into space in the early 1960s, the need for such an Emergency Escape System (EES) has become apparent. The National Aeronautics and Space Administration (NASA) has made use of various types of these EESs over the past 50 years. Early programs, like Mercury and Gemini, did not have an official launch pad escape system. Rather, they relied on a Launch Escape System (LES) of a separate solid rocket motor attached to the manned capsule that could pull the astronauts to safety in the event of an emergency. This could only occur after hatch closure at the launch pad or during the first stage of flight. A version of a LES, now called a Launch Abort System (LAS) is still used today for all manned capsule type launch vehicles. However, this system is very limited in that it can only be used after hatch closure and it is for flight crew only. In addition, the forces necessary for the LES/LAS to get the capsule away from a rocket during the first stage of flight are quite high and can cause injury to the crew. These shortcomings led to the development of a ground based EES for the flight crew and ground support personnel as well. This way, a much less dangerous mode of egress is available for any flight or ground personnel up to a few seconds before launch. The early EESs were fairly simple, gravity-powered systems to use when thing's go bad. And things can go bad very quickly and catastrophically when dealing with a flight vehicle fueled with millions of pounds of hazardous propellant. With this in mind, early EES designers saw such a passive/unpowered system as a must for last minute escapes. This and other design requirements had to be derived for an EES, and this section will take a look at the safety design requirements had to be derived for an EES, and this section will take a look at

  18. Russian Soyuz Moves to Launch Pad

    NASA Technical Reports Server (NTRS)

    2000-01-01

    The Soyuz TM-31 launch vehicle, which carried the first resident crew to the International Space Station, moves toward the launch pad at the Baikonur complex in Kazakhstan. The Russian Soyuz launch vehicle is an expendable spacecraft that evolved out of the original Class A (Sputnik). From the early 1960' until today, the Soyuz launch vehicle has been the backbone of Russia's marned and unmanned space launch fleet. Today, the Soyuz launch vehicle is marketed internationally by a joint Russian/French consortium called STARSEM. As of August 2001, there have been ten Soyuz missions under the STARSEM banner.

  19. Mars Science Laboratory Launch Pad Thermal Control

    NASA Technical Reports Server (NTRS)

    Bhandari, Pradeep; Dudik, Brenda; Birur, Gajanana; Bame, David

    2011-01-01

    This paper will describe the challenges faced in accommodating the warm Multi Mission Radioisotope Thermoelectric Generator (MMRTG) during the pre-launch phases of integration, launch pad operations as well as during launch. Predictions of temperatures during these phases will be presented when all the cooling systems (HRS and A/C) are operational. In-air tests conducted on the spacecraft in December 2008 to simulate the launch conditions were very successful and showed that all components would be within their allowable limits during these phases. Results of these tests will be shared in this paper.

  20. The physostigmine depolarization potentiating effect of salicylate in frog skeletal muscle.

    PubMed

    Varga, E; Kovács, L; Szücs, G; Illés, B

    1975-01-01

    1) The frog's sartorius muscle was depolarized depending on the degree of concentration 2--4 times more intensely by physostigmine salicylate than by physostigmine sulphate. 2) In normal Ringer's solution, 1 mM physostigmine salicylate decreased the sensitivity of the membrane to potassium depolarization by about 90%. Under similar experimental conditions, physostigmine sulphate and Na salicylate, respectively, decrease the sensitivity of the membrane to potassium depolarization by about 30%. 3) The difference manifested in the depolarizing effect of salicylate and other physostigmine salts (chloride, sulphate, phosphate, formiate, acetate, monochloracetate, benzoate and para-oxy-benzoate) is expressed already at 1 mM concentration (about 10-fold), if the muscle had been equilibrated in chloride-free glucuronate or sulphate milieu. 4) The depolarization develops slowly. It takes 30--60 minutes for the new steady state to develop even in the superficial sartorius fibres. If depolarization has reached its maximum on an average 100 mV, the membrane potential remains unchanged for hours. 5) Depolarization ensues at an unchanged degree in the presence of Na-free (choline) Ringer as well as in the presence of 2X10(-8) g/ml tetrodotoxin; therefore, it is not a Na-dependent process. 6) Under the influence of 1 mM physostigmine salicylate the membrane's resistance to the inward potassium current increased about twofold, while the increase was only 15% to the outward potassium current. It is assumed that the salicylate anion is characteristically capable of potentiating the decreasing effect of physostigmine on potassium permeability, though the role of the metabolic effect of salicylate cannot be excluded. PMID:1235230

  1. Spreading depolarizations increase delayed brain injury in a rat model of subarachnoid hemorrhage.

    PubMed

    Hamming, Arend M; Wermer, Marieke Jh; Umesh Rudrapatna, S; Lanier, Christian; van Os, Hine Ja; van den Bergh, Walter M; Ferrari, Michel D; van der Toorn, Annette; van den Maagdenberg, Arn Mjm; Stowe, Ann M; Dijkhuizen, Rick M

    2016-07-01

    Spreading depolarizations may contribute to delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage, but the effect of spreading depolarizations on brain lesion progression after subarachnoid hemorrhage has not yet been assessed directly. Therefore, we tested the hypothesis that artificially induced spreading depolarizations increase brain tissue damage in a rat model of subarachnoid hemorrhage. Subarachnoid hemorrhage was induced by endovascular puncture of the right internal carotid bifurcation. After one day, brain tissue damage was measured with T2-weighted MRI, followed by application of 1 M KCl (SD group, N = 16) or saline (no-SD group, N = 16) to the right cortex. Cortical laser-Doppler flowmetry was performed to record spreading depolarizations. MRI was repeated on day 3, after which brains were extracted for assessment of subarachnoid hemorrhage severity and histological damage. 5.0 ± 2.7 spreading depolarizations were recorded in the SD group. Subarachnoid hemorrhage severity and mortality were similar between the SD and no-SD groups. Subarachnoid hemorrhage-induced brain lesions expanded between days 1 and 3. This lesion growth was larger in the SD group (241 ± 233 mm(3)) than in the no-SD group (29 ± 54 mm(3)) (p = 0.001). We conclude that induction of spreading depolarizations significantly advances lesion growth after experimental subarachnoid hemorrhage. Our study underscores the pathophysiological consequence of spreading depolarizations in the development of delayed cerebral tissue injury after subarachnoid hemorrhage. PMID:26661246

  2. Capsaicin-sensitive vagal afferent neurons contribute to the detection of pathogenic bacterial colonization in the gut.

    PubMed

    Riley, T P; Neal-McKinney, J M; Buelow, D R; Konkel, M E; Simasko, S M

    2013-04-15

    Vagal activation can reduce inflammation and disease activity in various animal models of intestinal inflammation via the cholinergic anti-inflammatory pathway. In the current model of this pathway, activation of descending vagal efferents is dependent on a signal initiated by stimulation of vagal afferents. However, little is known about how vagal afferents are activated, especially in the context of subclinical or clinical pathogenic bacterial infection. To address this question, we first determined if selective lesions of capsaicin-sensitive vagal afferents altered c-Fos expression in the nucleus of the solitary tract (nTS) after mice were inoculated with either Campylobacter jejuni or Salmonella typhimurium. Our results demonstrate that the activation of nTS neurons by intraluminal pathogenic bacteria is dependent on intact, capsaicin sensitive vagal afferents. We next determined if inflammatory mediators could cause the observed increase in c-Fos expression in the nTS by a direct action on vagal afferents. This was tested by the use of single-cell calcium measurements in cultured vagal afferent neurons. We found that tumor necrosis factor alpha (TNFα) and lipopolysaccharide (LPS) directly activate cultured vagal afferent neurons and that almost all TNFα and LPS responsive neurons were sensitive to capsaicin. We conclude that activation of the afferent arm of the parasympathetic neuroimmune reflex by pathogenic bacteria in the gut is dependent on capsaicin sensitive vagal afferent neurons and that the release of inflammatory mediators into intestinal tissue can be directly sensed by these neurons. PMID:23481698

  3. Capsaicin-sensitive vagal afferent neurons contribute to the detection of pathogenic bacterial colonization in the gut

    PubMed Central

    Riley, T.P.; Neal-McKinney, J.M.; Buelow, D.R.; Konkel, M.E.; Simasko, S.M.

    2014-01-01

    Vagal activation can reduce inflammation and disease activity in various animal models of intestinal inflammation via the cholinergic anti-inflammatory pathway. In the current model of this pathway, activation of descending vagal efferents is dependent on a signal initiated by stimulation of vagal afferents. However, little is known about how vagal afferents are activated, especially in the context of subclinical or clinical pathogenic bacterial infection. To address this question, we first determined if selective lesions of capsaicin-sensitive vagal afferents altered c-Fos expression in the nucleus of the solitary tract (nTS) after mice were inoculated with either Campylobacter jejuni or Salmonella typhimurium. Our results demonstrate that the activation of nTS neurons by intraluminal pathogenic bacteria is dependent on intact, capsaicin sensitive vagal afferents. We next determined if inflammatory mediators could cause the observed increase in c-Fos expression in the nTS by a direct action on vagal afferents. This was tested by the use of single-cell calcium measurements in cultured vagal afferent neurons. We found that tumor necrosis factor alpha (TNFα) and lipopolysaccharide (LPS) directly activate cultured vagal afferent neurons and that almost all TNFα and LPS responsive neurons were sensitive to capsaicin. We conclude that activation of the afferent arm of the parasympathetic neuroimmune reflex by pathogenic bacteria in the gut is dependent on capsaicin sensitive vagal afferent neurons and that the release of inflammatory mediators into intestinal tissue can be directly sensed by these neurons. PMID:23481698

  4. Tilting pad gas bearing design for micro gas turbines

    NASA Astrophysics Data System (ADS)

    Nabuurs, M. J. H. W.; Al-Bender, F.; Reynaerts, D.

    2013-12-01

    This paper presents the results of a dynamic stability investigation of a micro gas turbine supported by two flexible tilting pad bearings. The pad flexibility allows centrifugal and thermal shaft growth of the rotor but can also introduce undesirable rotor instabilities. An eigenvalue analysis on the linearised rotor-bearing dynamics is performed to estimate the required pad stiffness and damping for stability. Results of the eigenvalue analysis are evaluated by fully nonlinear orbit simulations.

  5. Measuring pad-pad pinch strength in a non-human primate: Macaca fascicularis.

    PubMed

    Banks, Jacob J; Lavender, Steven A; Buford, John A; Sommerich, Carolyn M

    2007-12-01

    The primary purpose of this study was to establish a methodology for determining and perhaps predicting (via regression analysis of anthropometric measures) Macaca fascicularis isometric pinch strength for a specific task. The larger purpose of this work was to properly scale a pinching task for the monkeys in order to study dose-response relationships in a non-human primate model for carpal tunnel syndrome. Three female and one male macaque (n=4) of varying size and age were trained to perform a left-handed pad-pad pinch. The task required 60 degrees of wrist flexion at a static pinching distance of 3 cm between the thumb and fingers. Subjects were trained for a period of 20-weeks. After that time, an analysis of performance gradients found that they had each reached a plateau in their force output. Pinch strength for the four animals ranged from 29.4 to 59.8 N. Regression analysis revealed that body mass (kg) and wrist circumference (cm) were both predictive of pinch strength, exhibiting adjusted R(2) values of 0.93 (p=0.024) and 0.96 (p=0.015), respectively. Thus, the results suggest that maximal pinch strength could be acceptably estimated in future subjects using either the wrist circumference or the body mass measures, as both were strong predictors of pad-pad pinch strength. PMID:17035044

  6. Tilting pad journal bearings - Measured and predicted stiffness coefficients

    SciTech Connect

    Parkins, D.W.; Horner, D. Michell Bearings, Newcastle-upon-Tyne )

    1993-07-01

    This paper presents measured and calculated characteristics of a tilting pad journal bearing suitable for high speed machinery. Descriptions are given of the experimental techniques used with this variety of bearing and the theoretical model for predicting performance. Measured values of pad temperature, eccentricity, attitude angle, and the four stiffness coefficients are given for a range of loads and rotational speeds. Data are given for both load on pad and between pad configurations, the two principal loading arrangements. Comparisons are made between the measured and predicted bearing temperatures and stiffness coefficients over a wide range of values. 11 refs.

  7. Pad Safety Personnel Launch Support For STS-200

    NASA Technical Reports Server (NTRS)

    Guarino, Jennifer

    2007-01-01

    The launch of a space shuttle is a complex and lengthy procedure. There are many places and components to look at and prepare. The components are the orbiter, solid rocket boosters, external tank, and ground equipment. Some of the places are the launch pad, fuel locations, and surrounding structures. Preparations for a launch include equipment checks, system checks, sniff checks for hazardous commodities, and countless walkdowns. Throughout these preparations, pad safety personnel must always be on call. This requires three shifts of multiple people to be ready when needed. Also, the pad safety personnel must be available for the non-launch tasks that are always present for both launch pads

  8. Tilting pad journal bearings - Measured and predicted stiffness coefficients

    NASA Astrophysics Data System (ADS)

    Parkins, D. W.; Horner, D.

    1993-07-01

    This paper presents measured and calculated characteristics of a tilting pad journal bearing suitable for high speed machinery. Descriptions are given of the experimental techniques used with this variety of bearing and the theoretical model for predicting performance. Measured values of pad temperature, eccentricity, attitude angle, and the four stiffness coefficients are given for a range of loads and rotational speeds. Data are given for both load on pad and between pad configurations, the two principal loading arrangements. Comparisons are made between the measured and predicted bearing temperatures and stiffness coefficients over a wide range of values.

  9. Transcriptional profile in afferent lymph cells following vaccination with liposomes incorporating CpG

    PubMed Central

    Neeland, Melanie R; Elhay, Martin J; Powell, David R; Rossello, Fernando J; Meeusen, Els N T; de Veer, Michael J

    2015-01-01

    Vaccine formulations incorporating innate immune stimulants are highly immunogenic; however, the biological signals that originate in the peripheral tissues at the site of injection and are transmitted to the local lymph node to induce immunity remain unclear. By directly cannulating the ovine afferent lymphatic vessels, we have previously shown that it takes 72 hr for mature antigen-loaded dendritic cells and monocytes to appear within afferent lymph following injection of a liposomal formulation containing the Toll-like receptor ligand CpG. In this present study, we characterize the global transcriptional signatures at this time-point in ovine afferent lymph cells as they migrate from the injection site into the lymphatics following vaccination with a liposome antigen formulation incorporating CpG. We show that at 72 hr post vaccination, liposomes alone induce no changes in gene expression and inflammatory profiles within afferent lymph; however, the incorporation of CpG drives interferon, antiviral and cytotoxic gene programmes. This study also measures the expression of key genes within individual cell types in afferent lymph. Antiviral gene signatures are most prominent in lymphocytes, which may play a significant and unexpected role in sustaining the immune response to vaccination at the site of injection. These findings provide a comprehensive analysis of the in vivo immunological pathways that connect the injection site with the local draining lymph node following vaccination. PMID:25308816

  10. Transcriptional profile in afferent lymph cells following vaccination with liposomes incorporating CpG.

    PubMed

    Neeland, Melanie R; Elhay, Martin J; Powell, David R; Rossello, Fernando J; Meeusen, Els N T; de Veer, Michael J

    2014-10-10

    Vaccine formulations incorporating innate immune stimulants are highly immunogenic, however the biological signals that originate in the peripheral tissues at the site of injection and are transmitted to the local lymph node to induce immunity remain unclear. By directly cannulating the ovine afferent lymphatic vessels, we have previously shown that it takes 72 hours for mature antigen-loaded dendritic cells and monocytes to appear within afferent lymph following injection of a liposomal formulation containing the TLR ligand CpG. In this present study, we characterise the global transcriptional signatures at this time point in ovine afferent lymph cells as they migrate from the injection site into the lymphatics following vaccination with a liposome antigen formulation incorporating CpG. We show that at 72h post vaccination, liposomes alone induce no changes in gene expression and inflammatory profiles within afferent lymph; however the incorporation of CpG drives interferon, antiviral and cytotoxic gene programs. This study also measures the expression of key genes within individual cell types in afferent lymph. Antiviral gene signatures are most prominent in lymphocytes, which may play a significant and unexpected role in sustaining the immune response to vaccination at the site of injection. These findings provide a comprehensive analysis of the in vivo immunological pathways that connect the injection site with the local draining lymph node following vaccination. This article is protected by copyright. All rights reserved. PMID:25308816

  11. Ventral hippocampal afferents to the nucleus accumbens regulate susceptibility to depression

    PubMed Central

    Bagot, Rosemary C.; Parise, Eric M.; Peña, Catherine J.; Zhang, Hong-Xing; Maze, Ian; Chaudhury, Dipesh; Persaud, Brianna; Cachope, Roger; Bolaños-Guzmán, Carlos A.; Cheer, Joseph; Deisseroth, Karl; Han, Ming-Hu; Nestler, Eric J.

    2015-01-01

    Enhanced glutamatergic transmission in the nucleus accumbens (NAc), a region critical for reward and motivation, has been implicated in the pathophysiology of depression; however, the afferent source of this increased glutamate tone is not known. The NAc receives glutamatergic inputs from the medial prefrontal cortex (mPFC), ventral hippocampus (vHIP) and basolateral amygdala (AMY). Here, we demonstrate that glutamatergic vHIP afferents to NAc regulate susceptibility to chronic social defeat stress (CSDS). We observe reduced activity in vHIP in mice resilient to CSDS. Furthermore, attenuation of vHIP-NAc transmission by optogenetic induction of long-term depression is pro-resilient, whereas acute enhancement of this input is pro-susceptible. This effect is specific to vHIP afferents to the NAc, as optogenetic stimulation of either mPFC or AMY afferents to the NAc is pro-resilient. These data indicate that vHIP afferents to NAc uniquely regulate susceptibility to CSDS, highlighting an important, novel circuit-specific mechanism in depression. PMID:25952660

  12. Paraventricular nucleus is involved in the central pathway of adipose afferent reflex in rats.

    PubMed

    Shi, Zhen; Wang, Yuan-Fang; Wang, Gui-Hua; Wu, Yu-Long; Ma, Chun-Lei

    2016-05-01

    Increasing evidence indicates a link between sympathetic nervous system activation and obesity, but the underlying mechanisms remain elusive. The adipose afferent reflex (AAR) is a sympathoexcitatory reflex that is activated by afferent neurotransmission from the white adipose tissue (WAT). This study aimed to investigate whether the hypothalamic paraventricular nucleus (PVH) is an important component of the central neurocircuitry of the AAR. In anesthetized rats, the discharge activity of individual PVH neurons was recorded in vivo. Activation of WAT afferents was initiated by capsaicin injection, and the AAR was evaluated by monitoring renal sympathetic nerve activity (RSNA) and mean arterial pressure (MAP) responses. The responses of PVH neurons to activation of WAT afferents were evaluated by c-fos immunoreactivity and the discharge activity of individual PVH neurons, which was recorded using extracellular single-unit recording. After activation of WAT afferents, both individual PVH neuron discharge activity and c-fos immunoreactivity increased. Bilateral selective lesions of the neurons in the PVH with kainic acid abolished the AAR. These results indicate that PVH is an important component of the central neurocircuitry of the AAR. PMID:26963333

  13. Gecko adhesion pad: a smart surface?

    NASA Astrophysics Data System (ADS)

    Pesika, Noshir S.; Zeng, Hongbo; Kristiansen, Kai; Zhao, Boxin; Tian, Yu; Autumn, Kellar; Israelachvili, Jacob

    2009-11-01

    Recently, it has been shown that humidity can increase the adhesion of the spatula pads that form the outermost (adhesive) surface of the tokay gecko feet by 50% relative to the main adhesion mechanism (i.e. van der Waals adhesive forces), although the mechanism by which the enhancement is realized is still not well understood. A change in the surface hydrophobicity of a gecko setal array is observed when the array, which supports the spatulae, is exposed to a water drop for more than 20 min, suggesting a change in the hydrophilic-lyophilic balance (HLB), and therefore of the conformation of the surface proteins. A surface force apparatus (SFA) was used to quantify these changes, i.e. in the adhesion and friction forces, while shearing the setal array against a silica surface under (i) dry conditions, (ii) 100% humidity and (iii) when fully immersed in water. The adhesion increased in the humid environment but greatly diminished in water. Although the adhesion forces changed significantly, the friction forces remained unaffected, indicating that the friction between these highly textured surfaces is 'load-controlled' rather than 'adhesion-controlled'. These results demonstrate that the gecko adhesive pads have the ability to exploit environmental conditions to maximize their adhesion and stabilize their friction forces. Future designs of synthetic dry adhesives inspired by the gecko can potentially include similar 'smart' surfaces that adapt to their environment.

  14. Launch Pad 39 Hail Monitor Array System

    NASA Technical Reports Server (NTRS)

    2008-01-01

    Weather conditions at Kennedy Space Center are extremely dynamic, and they greatly affect the safety of the Space Shuttles sitting on the launch pads. For example, on May 13, 1999, the foam on the External Tank (ET) of STS-96 was significantly damaged by hail at the launch pad, requiring rollback to the Vehicle Assembly Building. The loss of ET foam on STS-114 in 2005 intensified interest in monitoring and measuring damage to ET foam, especially from hail. But hail can be difficult to detect and monitor because it is often localized and obscured by heavy rain. Furthermore, the hot Florida climate usually melts the hail even before the rainfall subsides. In response, the hail monitor array (HMA) system, a joint effort of the Applied Physics Laboratory operated by NASA and ASRC Aerospace at KSC, was deployed for operational testing in the fall of 2006. Volunteers from the Community Collaborative Rain, Hail, and Snow (CoCoRaHS) network, in conjunction with Colorado State University, continue to test duplicate hail monitor systems deployed in the high plains of Colorado.

  15. The regularity of primary and secondary muscle spindle afferent discharges

    PubMed Central

    Matthews, P. B. C.; Stein, R. B.

    1969-01-01

    1. The patterns of nerve impulses in the afferent fibres from muscle spindles have been studied using the soleus muscle of the decerebrate cat. Impulses from up to five single units were recorded simultaneously on magnetic tape, while the muscle was stretched to a series of different lengths. Various statistics were later determined by computer analysis. 2. After the ventral roots were cut to eliminate any motor outflow to the muscle spindles, both primary and secondary spindle endings discharged very regularly. At frequencies around 30 impulses/sec the coefficient of variation of the interspike interval distributions had a mean value of only 0·02 for the secondary endings and 0·058 for the primary endings. The values obtained for the two kinds of ending did not overlap. 3. When the ventral roots were intact, the `spontaneous' fusimotor activity considerably increased the variability of both kinds of endings. Secondary endings still discharged much more regularly than primary endings, even when the fusimotor activity increased the frequency of firing equally for the two kinds of endings. At frequencies around 30/sec the average coefficient of variation of the interval distributions was then 0·064 for the secondary endings and 0·25 for the primary endings. 4. When the ventral roots were intact there was usually an inverse relation between the values of successive interspike intervals. The first serial correlation coefficient often had values down to - 0·6 for both kinds of ending. Higher order serial correlation coefficients were also computed. 5. Approximate calculations, based on the variability observed when the ventral roots were intact, suggested that when the length of the muscle was constant an observer analysing a 1 sec period of discharge from a single primary ending would only be able to distinguish about six different lengths of the muscle. The corresponding figure for a secondary ending was twenty-five lengths. 6. The increase in variability with

  16. Mechanism of blue-light-induced plasma-membrane depolarization in etiolated cucumber hypocotyls

    NASA Technical Reports Server (NTRS)

    Spalding, E. P.; Cosgrove, D. J.

    1992-01-01

    A large, transient depolarization of the plasma membrane precedes the rapid blue-light (BL)-induced growth suppression in etiolated seedlings of Cucumis sativus L. The mechanism of this voltage transient was investigated by applying inhibitors of ion channels and the plasma-membrane H(+)-ATPase, by manipulating extracellular ion concentrations, and by measuring cell input resistance and ATP levels. The depolarizing phase was not affected by Ca(2+)-channel blockers (verapamil, La3+) or by reducing extracellular free Ca2+ by treatment with ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA). However, these treatments did reduce the rate of repolarization, indicating an inward movement of Ca2+ is involved. No effects of the K(+)-channel blocker tetraethylammonium (TEA+) were detected. Vanadate and KCN, used to inhibit the H(+)-ATPase, reduced or completely inhibited the BL-induced depolarization. Levels of ATP increased by 11-26% after 1-2 min of BL. Input resistance of trichrome cells, measured with double-barreled microelectrodes, remained constant during the onset of the depolarization but decreased as the membrane voltage became more positive than -90 mV. The results indicate that the depolarization mechanism initially involves inactivation of the H(+)-ATPase with subsequent transient activation of one or more types of ion channels.

  17. Quantitative correlation between light depolarization and transport albedo of various porcine tissues

    NASA Astrophysics Data System (ADS)

    Alali, Sanaz; Ahmad, Manzoor; Kim, Anthony; Vurgun, Nasit; Wood, Michael F. G.; Vitkin, I. Alex

    2012-04-01

    We present a quantitative study of depolarization in biological tissues and correlate it with measured optical properties (reduced scattering and absorption coefficients). Polarized light imaging was used to examine optically thick samples of both isotropic (liver, kidney cortex, and brain) and anisotropic (cardiac muscle, loin muscle, and tendon) pig tissues in transmission and reflection geometries. Depolarization (total, linear, and circular), as derived from polar decomposition of the measured tissue Mueller matrix, was shown to be related to the measured optical properties. We observed that depolarization increases with the transport albedo for isotropic and anisotropic tissues, independent of measurement geometry. For anisotropic tissues, depolarization was higher compared to isotropic tissues of similar transport albedo, indicating birefringence-caused depolarization effects. For tissues with large transport albedos (greater than ~0.97), backscattering geometry was preferred over transmission due to its greater retention of light polarization; this was not the case for tissues with lower transport albedo. Preferential preservation of linearly polarized light over circularly polarized light was seen in all tissue types and all measurement geometries, implying the dominance of Rayleigh-like scattering. The tabulated polarization properties of different tissue types and their links to bulk optical properties should prove useful in future polarimetric tissue characterization and imaging studies.

  18. 40 CFR 265.442 - Design and installation of new drip pads.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... pads. 265.442 Section 265.442 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED..., STORAGE, AND DISPOSAL FACILITIES Drip Pads § 265.442 Design and installation of new drip pads. Owners and operators of new drip pads must ensure that the pads are designed, installed, and operated in...

  19. 40 CFR 264.572 - Design and installation of new drip pads.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... pads. 264.572 Section 264.572 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... DISPOSAL FACILITIES Drip Pads § 264.572 Design and installation of new drip pads. Owners and operators of new drip pads must ensure that the pads are designed, installed, and operated in accordance with...

  20. Naturalistic Stimuli Increase the Rate and Efficiency of Information Transmission by Primary Auditory Afferents

    NASA Astrophysics Data System (ADS)

    Rieke, F.; Bodnar, D. A.; Bialek, W.

    1995-12-01

    Natural sounds, especially communication sounds, have highly structured amplitude and phase spectra. We have quantified how structure in the amplitude spectrum of natural sounds affects coding in primary auditory afferents. Auditory afferents encode stimuli with naturalistic amplitude spectra dramatically better than broad-band stimuli (approximating white noise); the rate at which the spike train carries information about the stimulus is 2-6 times higher for naturalistic sounds. Furthermore, the information rates can reach 90% of the fundamental limit to information transmission set by the statistics of the spike response. These results indicate that the coding strategy of the auditory nerve is matched to the structure of natural sounds; this `tuning' allows afferent spike trains to provide higher processing centres with a more complete description of the sensory world.

  1. Structure of the Afferent Terminals in Terminal Ganglion of a Cricket and Persistent Homology

    PubMed Central

    Brown, Jacob; Gedeon, Tomáš

    2012-01-01

    We use topological data analysis to investigate the three dimensional spatial structure of the locus of afferent neuron terminals in crickets Acheta domesticus. Each afferent neuron innervates a filiform hair positioned on a cercus: a protruding appendage at the rear of the animal. The hairs transduce air motion to the neuron signal that is used by a cricket to respond to the environment. We stratify the hairs (and the corresponding afferent terminals) into classes depending on hair length, along with position. Our analysis uncovers significant structure in the relative position of these terminal classes and suggests the functional relevance of this structure. Our method is very robust to the presence of significant experimental and developmental noise. It can be used to analyze a wide range of other point cloud data sets. PMID:22649516

  2. Light-evoked depolarizations in the retina of Strombus: role of sodium and potassium ions.

    PubMed

    Chinn, K S; Gillary, H L

    1985-01-01

    Light-evoked depolarizations (LED's) in retinal cells of Strombus luhuanus can exhibit an early phase of depolarization (DE), a brief repolarizing phase (RE), and a later depolarizing phase (DL). Lowering external Na+ by substitution with choline, tetramethylammonium or sucrose, reduced the amplitude of the entire LED, but DL was reduced more than DE. Replacement of Na+ with Li+ reduced DE more than DL. Lowering pH reduced DL more than DE, while raising it increased DL but not DE. K+ channel blocking agents, tetraethylammonium and 4-aminopyridine, increased RE. During the LED, cell membrane conductance increased in two phases, corresponding to DE and DL. The results suggest LED generation by two separable conductance increases to Na+, corresponding to DE and DL, and another to K+ during RE. PMID:2579764

  3. Retrievals of Aerosol and Cloud Particle Microphysics Using Polarization and Depolarization Techniques

    NASA Technical Reports Server (NTRS)

    Mishchenko, Michael; Hansen, James E. (Technical Monitor)

    2001-01-01

    The recent availability of theoretical techniques for computing single and multiple scattering of light by realistic polydispersions of spherical and nonspherical particles and the strong dependence of the Stokes scattering matrix on particle size, shape, and refractive index make polarization and depolarization measurements a powerful particle characterization tool. In this presentation I will describe recent applications of photopolarimetric and lidar depolarization measurements to remote sensing characterization of tropospheric aerosols, polar stratospheric clouds (PSCs), and contrails. The talk will include (1) a short theoretical overview of the effects of particle microphysics on particle single-scattering characteristics; (2) the use of multi-angle multi-spectral photopolarimetry to retrieve the optical thickness, size distribution, refractive index, and number concentration of tropospheric aerosols over the ocean surface; and (3) the application of the T-matrix method to constraining the PSC and contrail particle microphysics using multi-spectral measurements of lidar backscatter and depolarization.

  4. Coherence and polarization of polarization speckle generated by a rough-surfaced retardation plate depolarizer.

    PubMed

    Ma, Ning; Hanson, Steen G; Takeda, Mitsuo; Wang, Wei

    2015-12-01

    The coherence and polarization of polarization speckle, arising from a stochastic electromagnetic field with random change of polarization, modulated by a depolarizer are examined on the basis of the coherence matrix. The depolarizer is a rough-surfaced retardation plate with a random function of position introducing random phase differences between the two orthogonal components of the electric vector. Under the assumption of Gaussian statistics with zero mean, the surface model for the depolarizer of the rough-surfaced retardation plate is obtained. The propagation of the modulated fields through any quadratic optical system is examined within the framework of the complex ABCD matrix theory to show how the degree of coherence and polarization of the beam changes on propagation, including propagation in free space. PMID:26831388

  5. Characterization of depolarizing optical media by means of the entropy factor: application to biological tissues

    NASA Astrophysics Data System (ADS)

    Pereda Cubián, David; Arce Diego, José Luis; Rentmeesters, Raf

    2005-01-01

    Polarized light imaging is a potential tool to obtain an adequate description of the properties of depolarizing media such as biological tissues. In many biomedical applications, for instance, dermatology, ophthalmology, or urology, imaging polarimetry provides a noninvasive diagnosis of a wide range of disease states, and, likewise, it could be applied to the study of internal tissues though the use of endoscopes that use optical fibers. We introduce an algebraic method, based on the Mueller-coherence matrix, for a clearer analysis of the polarization characteristics of depolarizing media via the entropy factor. First-order errors introduced by the measurement system are corrected. Entropy defines three kinds of media according to their depolarizing behavior, and several examples corresponding to each region are shown. The calculation of this factor provides clearer information than that provided by the traditional Mueller matrix in the analysis of biological tissue properties by polarization measurement techniques.

  6. GABA depolarizes immature neurons and inhibits network activity in the neonatal neocortex in vivo.

    PubMed

    Kirmse, Knut; Kummer, Michael; Kovalchuk, Yury; Witte, Otto W; Garaschuk, Olga; Holthoff, Knut

    2015-01-01

    A large body of evidence from in vitro studies suggests that GABA is depolarizing during early postnatal development. However, the mode of GABA action in the intact developing brain is unknown. Here we examine the in vivo effects of GABA in cells of the upper cortical plate using a combination of electrophysiological and Ca(2+)-imaging techniques. We report that at postnatal days (P) 3-4, GABA depolarizes the majority of immature neurons in the occipital cortex of anaesthetized mice. At the same time, GABA does not efficiently activate voltage-gated Ca(2+) channels and fails to induce action potential firing. Blocking GABA(A) receptors disinhibits spontaneous network activity, whereas allosteric activation of GABA(A) receptors has the opposite effect. In summary, our data provide evidence that in vivo GABA acts as a depolarizing neurotransmitter imposing an inhibitory control on network activity in the neonatal (P3-4) neocortex. PMID:26177896

  7. Conductivity Variation Observed by Polarization and Depolarization Current Measurements of High-Voltage Equipment Insulation System

    NASA Astrophysics Data System (ADS)

    Jamail, Nor Akmal Mohd; Piah, Mohamed Afendi Mohamed; Muhamad, Nor Asiah

    2012-09-01

    Nondestructive and time domain dielectric measurement techniques such as polarization and depolarization current (PDC) measurements have recently been widely used as a potential tool for determining high-voltage insulation conditions by analyzing the insulation conductivity. The variation in the conductivity of an insulator was found to depend on several parameters: the difference between the polarization and depolarization currents, geometric capacitance, and the relative permittivity of the insulation material. In this paper the conductivities of different types of oil-paper insulation material are presented. The insulation conductivities of several types of electrical apparatus were simulated using MATLAB. Conductivity insulation was found to be high at high polarizations and at the lowest depolarization current. It was also found to increase with increasing relative permittivity as well as with decreasing geometric capacitance of the insulating material.

  8. Light-induced depolarization of neurons using a modified Shaker K(+) channel and a molecular photoswitch.

    PubMed

    Chambers, James J; Banghart, Matthew R; Trauner, Dirk; Kramer, Richard H

    2006-11-01

    To trigger action potentials in neurons, most investigators use electrical or chemical stimulation. Here we describe an optical stimulation method based on semi-synthetic light-activated ion channels. These SPARK (synthetic photoisomerizable azobenzene-regulated K(+)) channels consist of a synthetic azobenzene-containing photoswitch and a genetically modified Shaker K(+) channel protein. SPARK channels with a wild-type selectivity filter elicit hyperpolarization and suppress action potential firing when activated by 390 nm light. A mutation in the pore converts the K(+)-selective Shaker channel into a nonselective cation channel. Activation of this modified channel with the same wavelength of light elicits depolarization of the membrane potential. Expression of these depolarizing SPARK channels in neurons allows light to rapidly and reversibly trigger action potential firing. Hence, hyper- and depolarizing SPARK channels provide a means for eliciting opposite effects on neurons in response to the same light stimulus. PMID:16870840

  9. Reduced C-afferent fibre density affects perceived pleasantness and empathy for touch.

    PubMed

    Morrison, India; Löken, Line S; Minde, Jan; Wessberg, Johan; Perini, Irene; Nennesmo, Inger; Olausson, Håkan

    2011-04-01

    We examined patients with a heritable disorder associated with a mutation affecting the nerve growth factor beta gene. Their condition has been classified as hereditary sensory and autonomic neuropathy type V. Carriers of the mutation show a reduction in density of thin and unmyelinated nerve fibres, including C afferents. A distinct type of unmyelinated, low-threshold mechanoreceptive C fibre, the C-tactile afferent, is present in hairy but not glabrous skin of humans and other mammals. They have been implicated in the coding of pleasant, hedonic touch of the kind that occurs in affiliative social interactions. We addressed the relationship between C fibre function and pleasant touch perception in 10 individuals from a unique population of mutation carriers in Sweden. We also investigated the effect of reduced C-fibre density on patients' evaluation of observed interpersonal touch (empathy). Results showed that patients perceived gentle, slow arm stroking, optimal for eliciting C-tactile afferent responses (1-10  cm/s), as less pleasant than did matched controls and also differed in their rating patterns across stimulation velocities. Further, patients' blood-oxygen-level-dependent responses in posterior insular cortex--a target for C afferents--were not modulated by stimulation optimal for activating C-tactile afferents. Hence, perception of the hedonic aspect of dynamic touch likely depends on C-tactile afferent density. Closely similar patterns between individuals' ratings of felt and seen touch suggest that appraisal of others' touch is anchored in one's own perceptual experience, whether typical or atypical. PMID:21378097

  10. The innate response to peanut extract in ovine afferent lymph and its correlation with allergen sensitisation.

    PubMed

    Van Gramberg, Jenna L; Bischof, Robert J; O'Hehir, Robyn E; de Veer, Michael J; Meeusen, Els N

    2015-07-01

    The innate response generated after initial allergen exposure is crucial for polarising adaptive immunity, but little is known about how it drives an atopic or type-2 immune response. The present study characterises the response of skin-draining afferent lymph in sheep following injection with peanut (PN) extract in the presence or absence of aluminium hydroxide (AlOH) adjuvant. Lymph was collected and innate cell populations characterised over an 84 h time period. The innate response to PN extract in afferent lymph displayed an early increase in neutrophils and monocytes without any changes in the dendritic cell (DC) population. PN antigen was transported by neutrophils and monocytes for the first 36 h, after which time DCs were the major antigen trafficking cells. AlOH adjuvant gradually increased antigen uptake by DCs at the later time points. Following lymphatic characterisation, sheep were sensitised with PN extract by three subcutaneous injections of PN in AlOH, and the level of PN-specific immunoglobulin E (IgE) was determined. Sheep with higher levels of steady-state DCs in afferent lymph showed increased monocytic recruitment in afferent lymph and reduced PN-specific IgE following sensitisation. In addition, DCs from afferent lymph that had ingested PN antigen increased the expression of monocyte chemoattractant mRNA. The results of this study show that the innate response to PN extract involves a dynamic change in cell populations in the afferent lymph over time. In addition, DCs may determine the strength of the initial inflammatory cell response, which in turn may determine the nature of the antigen-specific adaptive response. PMID:25666095

  11. Botulinum toxin in Migraine: Role of transport in trigemino-somatic and trigemino-vascular afferents

    PubMed Central

    Roshni, Ramachandran; Carmen, Lam; Yaksh Tony, L

    2015-01-01

    Migraine secondary to meningeal input is referred to extracranial regions innervated by somatic afferents that project to homologous regions in the trigeminal nucleus caudalis (TNC). Reported efficacy of extracranial botulinum toxin (BoNT) in treating migraine is surprising since a local extracranial effect of BoNT cannot account for its effect upon meningeal input. We hypothesize that intradermal BoNT acts through central transport in somatic afferents. Anesthetized C57Bl/6 mice (male) received unilateral supraorbital (SO) injections of BoNT-B (1.5 U/40 μl) or saline. 3 days later, mice received ipsilateral (ipsi) -SO capsaicin (2.5 μg/30 μl) or meningeal capsaicin (4 μl of 1mg/ml). Pre-treatment with ipsi-SO BONT-B i) decreased nocicsponsive ipsilateral wiping behavior following ipsi-SO capsaicin; ii) produced cleavage of VAMP in the V1 region of ipsi-TG and in TG neurons showing WGA after SO injection; iii) reduced expression of c-fos in ipsi-TNC following ipsi-SO capsaicin; iv) reduced c-fos activation and NK-1 internalization in ipsi-TNC secondary to ipsi-meningeal capsaicin; vi) SO WGA did not label dural afferents. We conclude that BoNT-B is taken up by peripheral afferents and transported to central terminals where it inhibits transmitter release resulting in decreased activation of second order neurons. Further, this study supports the hypothesis that SO BoNT exerts a trans-synaptic action on either the second order neuron (which receives convergent input from the meningeal afferent) or the terminal/TG of the converging meningeal afferent. PMID:25958249

  12. Characterization of silent afferents in the pelvic and splanchnic innervations of the mouse colorectum

    PubMed Central

    Gebhart, G. F.

    2011-01-01

    Hypersensitivity in inflammatory/irritable bowel syndrome is contributed to in part by changes in the receptive properties of colorectal afferent endings, likely including mechanically insensitive afferents (MIAs; silent afferents) that have the ability to acquire mechanosensitivity. The proportion and attributes of colorectal MIAs, however, have not previously been characterized. The distal ∼3 cm of colorectum with either pelvic (PN) or lumbar splanchnic (LSN) nerve attached was removed, opened longitudinally, pinned flat in a recording chamber, and perfused with oxygenated Krebs solution. Colorectal receptive endings were located by electrical stimulation and characterized as mechanosensitive or not by blunt probing, mucosal stroking, and circumferential stretch. MIA endings were tested for response to and acquisition of mechanosensitivity by localized exposure to an inflammatory soup (IS). Colorectal afferents were also tested with twin-pulse and repetitive electrical stimulation paradigms. PN MIAs represented 23% of 211 afferents studied, 71% (30/42) of which acquired mechanosensitivity after application of IS to their receptive ending. LSN MIAs represented 33% of 156 afferents studied, only 23% (11/48) of which acquired mechanosensitivity after IS exposure. Mechanosensitive PN endings uniformly exhibited significant twin-pulse slowing whereas LSN endings showed no significant twin-pulse difference. PN MIAs displayed significantly greater activity-dependent slowing than LSN MIAs. In conclusion, significant proportions of MIAs are present in the colorectal innervation; significantly more in the PN than LSN acquire mechanosensitivity in an inflammatory environment. This knowledge contributes to our understanding of the possible roles of MIAs in colon-related disorders like inflammatory/irritable bowel syndrome. PMID:21071510

  13. Role of membrane depolarization and extracellular calcium in increased complement receptor expression during neutrophil (PMN) activation

    SciTech Connect

    Berger, M.; Wetzler, E.; Birx, D.L.

    1986-03-05

    During PMN activation the surface expression of receptors (R) for C3b and C3bi increases rapidly. This is necessary for optimal cell adhesion, migration, and phagocytosis. Following stimulation with fMLP or LTB-4, the increased expression of C3bR depends only on the Ca/sup + +/ released from intracellular stores and is not inhibited by 5mM EDTA, while the increase in C3biR also requires extracellular Ca/sup + +/. CR expression also increases when the PMN are depolarized with 140 mM K/sup +/, but with this stimulus, EDTA inhibits C3bR by 67% and C3biR 100%, suggesting that intracellular Ca/sup + +/ stores may not be released. Pertussis toxin caused dose-dependent inhibition of both CR responses to fMLP and also inhibited the increases in both CR induced by K/sup +/. Membrane depolarization (monitored by di-O-C5 fluorescence) due to fMLP was similarly inhibited by toxin but the depolarization due to K/sup +/ was not. The dose of phorbol myristate acetate that maximally increased CR expression, 0.1 ng/ml, did not depolarize the membrane. These results suggest that membrane depolarization is neither necessary nor sufficient for increased CR expression. A Ca/sup + +/ and GTP binding protein-dependent enzyme such as phospholipase C is necessary to the amplify initial signals generated either by release of Ca/sup + +/ stores or by opening voltage dependent Ca/sup + +/ channels following membrane depolarization.

  14. Light depolarization measurements in malaria: A new job for an old friend.

    PubMed

    Rebelo, Maria; Tempera, Carolina; Bispo, Claudia; Andrade, Claudia; Gardner, Rui; Shapiro, Howard M; Hänscheid, Thomas

    2015-05-01

    The use of flow cytometry in malaria research has increased over the last decade. Most approaches use nucleic acid stains to detect parasite DNA and RNA and require complex multi-color, multi-parameter analysis to reliably detect infected red blood cells (iRBCs). We recently described a novel and simpler approach to parasite detection based on flow cytometric measurement of scattered light depolarization caused by hemozoin (Hz), a pigment formed by parasite digestion of hemoglobin in iRBCs. Depolarization measurement by flow cytometry was described in 1987; however, patent issues restricted its use to a single manufacturer's hematology analyzers until 2009. Although we recently demonstrated that depolarization measurement of Hz, easily implemented on a bench top flow cytometer (Cyflow), provided useful information for malaria work, doubts regarding its application and utility remain in both the flow cytometry and malaria communities, at least in part because instrument manufacturers do not offer the option of measuring depolarized scatter. Under such circumstances, providing other researchers with guidance as to how to do this seemed to offer the most expeditious way to resolve the issue. We accordingly examined how several commercially available flow cytometers (CyFlow SL, MoFLo, Attune and Accuri C6) could be modified to detect depolarization due to the presence of free Hz on solution, or of Hz in leukocytes or erythrocytes from rodent or human blood. All were readily adapted, with substantially equivalent results obtained with lasers emitting over a wide wavelength range. Other instruments now available may also be modifiable for Hz measurement. Cytometric detection of Hz using depolarization is useful to study different aspects of malaria. Adding additional parameters, such as DNA content and base composition and RNA content, can demonstrably provide improved accuracy and sensitivity of parasite detection and characterization, allowing malaria researchers and

  15. CO2 decreases membrane conductance and depolarizes neurons in the nucleus tractus solitarii.

    PubMed

    Dean, J B; Lawing, W L; Millhorn, D E

    1989-01-01

    To identify central sites of potential CO2/H+-chemoreceptive neurons, and the mechanism responsible for neuronal chemosensitivity, intracellular recordings were made in rat tissue slices in two cardiopulmonary-related regions (i.e., nucleus tractus solitarii, NTS; nucleus ambiguus, AMBc) during exposure to high CO2. When the NTS was explored slices were bisected and the ventral half discarded. Utilizing such "dorsal" medullary slices removed any impinging synaptic input from putative chemoreceptors in the ventrolateral medulla. In the NTS, CO2-induced changes in firing rate were associated with membrane depolarizations ranging from 2-25 mV (n = 15). In some cases increased e.p.s.p. activity was observed during CO2 exposure. The CO2-induced depolarization occurred concomitantly with an increased input resistance ranging from 19-23 M omega (n = 5). The lower membrane conductance during hypercapnia suggests that CO2-induced depolarization is due to a decreased outward potassium conductance. Unlike neurons in the NTS, AMBc neurons were not spontaneously active and were rarely depolarized by hypercapnia. Eleven of 12 cells tested were either hyperpolarized by or insensitive to CO2. Only 1 neuron in the AMBc was depolarized and it also showed an increased input resistance during CO2 exposure. Our findings suggest that CO2/H+-related stimuli decrease potassium conductance which depolarizes the cell and increases firing rate. Although our in vitro studies cannot guarantee the specific function of these cells, we believe they may be involved with brain pH homeostasis and cardiopulmonary regulation. PMID:2507342

  16. Characterization of the anandamide induced depolarization of guinea-pig isolated vagus nerve

    PubMed Central

    Kagaya, Manabu; Lamb, Jasmine; Robbins, Jon; Page, Clive P; Spina, Domenico

    2002-01-01

    There is considerable interest in elucidating potential endogenously derived agonists of the vanilloid receptor and the role of anandamide in this regard has received considerable attention. In the present study, we have used an electrophysiological technique to investigate the mechanism of activation of vanilloid receptors in an isolated vagal preparation. Both capsaicin and anandamide depolarized de-sheathed whole vagal nerve preparations that was antagonized by the VR1 antagonist, capsazepine (P<0.05) whilst this response was unaltered by the cannabinoid (CB1) selective antagonist SR141716A or the CB2 selective antagonist, SR144528, thereby ruling out a role for cannabinoid receptors in this response. The PKC activator, phorbol-12-myristate-13-acetate (PMA) augmented depolarization to both anandamide and capsaicin and this response was significantly inhibited with the PKC inhibitor, bisindolylmaleimide (BIM) (P<0.05). The role of lipoxygenase products in the depolarization to anandamide was investigated in the presence of the lipoxygenase inhibitor, 5,8,11-Eicosatriynoic acid (ETI). Depolarization to anandamide and arachidonic acid was significantly inhibited in the presence of ET1 (P<0.05). However, in the absence of calcium depolarization to anandamide was not inhibited by ETI. Using confocal microscopy we have demonstrated the presence of vanilloid receptors on both neuropeptide containing nerves and nerves that did not stain for sensory neuropeptides. These results demonstrate that anandamide evokes depolarization of guinea-pig vagus nerve, following activation of vanilloid receptors, a component of which involves the generation of lipoxygenase products. Furthermore, these receptors are distributed in both neuropeptide and non-neuropeptide containing nerves. PMID:12183329

  17. Vagal afferent innervation of the rat fundic stomach: morphological characterization of the gastric tension receptor.

    PubMed

    Berthoud, H R; Powley, T L

    1992-05-01

    Although the gastric tension receptor has been characterized behaviorally and electrophysiologically quite well, its location and structure remains elusive. Therefore, the vagal afferents to the rat fundus (forestomach or nonglandular stomach) were anterogradely labeled in vivo with injections of the carbocyanine dye Dil into the nodose ganglia, and the nerves and ganglia of the enteric nervous system were labeled in toto with intraperitoneal Fluorogold injection. Dissected layers and cryostat cross sections of the fundic wall were mounted in glycerin and analyzed by means of conventional and laser scanning confocal microscopy. Particularly in the longitudinal, and to a lesser extent in the circular, smooth muscle layers, Dil-labeled fibers and terminals were abundant. These processes, which originated from fibers coursing through the myenteric ganglia and connectives, entered either muscle coat and then ran parallel to the respective muscle fibers, often for several millimeters. They ran in close association with the Fluorogold-labeled network of interstitial cells of Cajal, upon which they appeared to form multiple spiny appositions or varicosities. In the myenteric plexus, two different types of afferent vagal structures were observed. Up to 300 highly arborizing endings forming dense accumulations of small puncta similar to the esophageal intraganglionic laminar endings (Rodrigo et al., '75 Acta Anat. 92:79-100) were found in the fundic wall ipsilateral to the injected nodose ganglion. They often covered small clusters of myenteric neurons or even single isolated ganglion cells (mean = 5.8 neurons) and tended to extend throughout the neuropil of the ganglia. In a second pattern, fine varicose fibers with less profuse arborizations innervated mainly the central regions of myenteric ganglia. Camera lucida analyses established that single vagal afferent fibers had separate collaterals in both a smooth muscle layer and the myenteric ganglia. Finally, Dil

  18. Spatial orientation of semicircular canals and afferent sensitivity vectors in pigeons.

    PubMed

    Dickman, J D

    1996-09-01

    Rotational head motion in vertebrates is detected by the semicircular canal system, whose innervating primary afferent fibers carry information about movement in specific head planes. The semicircular canals have been qualitatively examined over a number of years, and the canal planes have been quantitatively characterized in several animal species. The present study first determined the geometric relationship between individual semicircular canals and between the canals and the stereotactic head planes in pigeons. Stereotactic measurements of multiple points along the circumference of the bony canals were taken, and the measured points fitted with a three-dimensional planar surface. Direction normals to the plane's surface were calculated and used to define angles between semicircular canal pairs. Because of the unusual shape of the anterior semicircular canals in pigeons, two planes, a major and a minor, were fitted to the canal's course. Calculated angle values for all canals indicated that the horizontal and posterior semicircular canals are nearly orthogonal, but the anterior canals have substantial deviations from orthogonality with other canal planes. Next, the responses of the afferent fibers that innervate each of the semicircular canals to 0.5 Hz sinusoidal rotation about an earth-vertical axis were obtained. The head orientation relative to the rotation axis was systematically varied so that directions of maximum sensitivity for each canal afferent could be determined. These sensitivity vectors were then compared with the canal plane direction normals. The afferents that innervated specific semicircular canals formed homogeneous clusters of sensitivity vectors in different head planes. The horizontal and posterior afferents had average sensitivity vectors that were largely co-incident with the innervated canal plane direction normals. Anterior canal afferents, however, appeared to synthesize contributions from the major and minor plane components of the

  19. Spatial orientation of semicircular canals and afferent sensitivity vectors in pigeons

    NASA Technical Reports Server (NTRS)

    Dickman, J. D.

    1996-01-01

    Rotational head motion in vertebrates is detected by the semicircular canal system, whose innervating primary afferent fibers carry information about movement in specific head planes. The semicircular canals have been qualitatively examined over a number of years, and the canal planes have been quantitatively characterized in several animal species. The present study first determined the geometric relationship between individual semicircular canals and between the canals and the stereotactic head planes in pigeons. Stereotactic measurements of multiple points along the circumference of the bony canals were taken, and the measured points fitted with a three-dimensional planar surface. Direction normals to the plane's surface were calculated and used to define angles between semicircular canal pairs. Because of the unusual shape of the anterior semicircular canals in pigeons, two planes, a major and a minor, were fitted to the canal's course. Calculated angle values for all canals indicated that the horizontal and posterior semicircular canals are nearly orthogonal, but the anterior canals have substantial deviations from orthogonality with other canal planes. Next, the responses of the afferent fibers that innervate each of the semicircular canals to 0.5 Hz sinusoidal rotation about an earth-vertical axis were obtained. The head orientation relative to the rotation axis was systematically varied so that directions of maximum sensitivity for each canal afferent could be determined. These sensitivity vectors were then compared with the canal plane direction normals. The afferents that innervated specific semicircular canals formed homogeneous clusters of sensitivity vectors in different head planes. The horizontal and posterior afferents had average sensitivity vectors that were largely co-incident with the innervated canal plane direction normals. Anterior canal afferents, however, appeared to synthesize contributions from the major and minor plane components of the

  20. Creating Microcomputer Graphics with the KoalaPad.

    ERIC Educational Resources Information Center

    White, Dennis W.

    1985-01-01

    The KoalaPad, an advanced graphic tablet introduced in 1983, reduces the cost and the degree of programing background required to create sophisticated images on the microcomputer. The potentials of the KoalaPad for use in an art education program are discussed, and recommendations for creating a microcomputer graphics lab are presented. (RM)

  1. 50. SOUTHEAST CORNER OF LAUNCH PAD. RAIL AND BUMPER IN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    50. SOUTHEAST CORNER OF LAUNCH PAD. RAIL AND BUMPER IN CENTER OF PHOTOGRAPH; FIRE SUPPRESSION NOZZLES ON RIGHT; THRUST SECTION HEATER DUCT ON LEFT. COMMUNICATIONS HOOKUP FOR THE MST LEFT OF DUCT. - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 East, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

  2. 14. VIEW OF MST, FACING SOUTHEAST, AND LAUNCH PAD TAKEN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. VIEW OF MST, FACING SOUTHEAST, AND LAUNCH PAD TAKEN FROM NORTHEAST PHOTO TOWER WITH WINDOW OPEN. FEATURES LEFT TO RIGHT: SOUTH TELEVISION CAMERA TOWER, SOUTHWEST PHOTO TOWER, LAUNCHER, UMBILICAL MAST, MST, AND OXIDIZER APRON. - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 East, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

  3. 42. VIEW OF UMBILICAL MAST AND LAUNCH PAD FROM MST ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    42. VIEW OF UMBILICAL MAST AND LAUNCH PAD FROM MST BASE. LAUNCHER IS BEHIND UMBILICAL MAST AND RAIL SYSTEM IS PARALLEL TO MAST ON RIGHT AND LEFT. - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 East, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

  4. 41. VIEW OF UMBILICAL MAST AND LAUNCH PAD FROM LAUNCHER; ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    41. VIEW OF UMBILICAL MAST AND LAUNCH PAD FROM LAUNCHER; SOUTH FACE OF MST IN BACKGROUND. RAIL SYSTEM FROM BASE OF MST PARALLEL TO MAST. - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 East, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

  5. iPad Use and Student Engagement in the Classroom

    ERIC Educational Resources Information Center

    Mango, Oraib

    2015-01-01

    iPads and handheld digital devices have been securing their place in educational institutions surrounded by debates between advocates and skeptics. In light of not enough evidence supporting the use of iPads in education, this study examined the ways that college students in two foreign language classrooms perceived the influence of the use of…

  6. 1. GENERAL VIEW OF PAD B MOBILE SERVICE STRUCTURE IN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. GENERAL VIEW OF PAD B MOBILE SERVICE STRUCTURE IN SETTING WITH FACILITY 28416 (PAD A MOBILE SERVICE STRUCTURE) IN DISTANCE; VIEW TO NORTHEAST. - Cape Canaveral Air Station, Launch Complex 17, Facility 28417, East end of Lighthouse Road, Cape Canaveral, Brevard County, FL

  7. Effectiveness of Using iPads to Build Math Fluency

    ERIC Educational Resources Information Center

    O'Malley, Patricia; Jenkins, Sandi; Wesley, Brooke; Donehower, Claire; Rabuck, Deidre; Lewis, MEB.

    2013-01-01

    Research into integrating technology such as iPads into the curriculum for students with disabilities is still new. The purpose of this study was to examine the effect of the use of a basic math skill application on an iPad to increase basic math fluency. As part of a classwide academic intervention, the study was conducted with 10 students with…

  8. iPads in Inclusive Classrooms: Ecologies of Learning

    ERIC Educational Resources Information Center

    Meyer, Bente

    2013-01-01

    This paper builds on data from a project where iPads were used in a lower secondary school in Denmark to support school development and inclusive learning environments. The paper explores how iPads enter into and work as part of an ecology of learning in five classes in lower secondary school. The paper argues that we should disengage approaches…

  9. DETAIL OF THE SLOPING CONCRETE PAD AT THE SOUTH SIDE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    DETAIL OF THE SLOPING CONCRETE PAD AT THE SOUTH SIDE OF THE GUN EMPLACEMENT. NOTE ADDED BLOCK OF CAST CONCRETE AT THE LOW (RIGHT) END OF SLOPED PAD. VIEW FACING SOUTHWEST - U.S. Naval Base, Pearl Harbor, Ford Island 5-Inch Antiaircraft Battery, East Gun Emplacement, Ford Island, Pearl City, Honolulu County, HI

  10. iPad use during ward rounds: an observational study.

    PubMed

    Lehnbom, Elin C; Adams, Kristian; Day, Richard O; Westbrook, Johanna I; Baysari, Melissa T

    2014-01-01

    Much clinical information is computerised and doctors' use of mobile devices such as iPad tablets to access this information is expanding rapidly. This study investigated the use of iPads during ward rounds and their usefulness in providing access to information during ward rounds. Ten teams of doctors at a large teaching hospital were given iPads for ten weeks and were observed on ward rounds for 77.3 hours as they interacted with 525 patients. Use of iPads and other information technology devices to access clinical information was recorded. The majority of clinical information was accessed using iPads (56.2%), followed by computers-on-wheels (35.8%), stationary PCs (7.9%) and smartphones (0.1%). Despite having read-only access on iPads, doctors were generally happy using iPads on ward rounds. These findings provide evidence of the value of iPads as a tool to access information at the point of care. PMID:25087529

  11. Teaching with Technology: iPads and Primary Mathematics

    ERIC Educational Resources Information Center

    Attard, Catherine

    2013-01-01

    iPads are beginning to appear in more and more primary classrooms, yet it is difficult to find teaching ideas that promote deep mathematical understanding. Catherine Attard provides a list of teaching considerations to be used when using iPads and two practical ideas for using them.

  12. 49. VIEW OF EAST SIDE OF LAUNCH PAD. THRUST SECTION ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    49. VIEW OF EAST SIDE OF LAUNCH PAD. THRUST SECTION HEATER AND DUCTS ON RIGHT; UMBILICAL MAST POWER CONNECTORS ON LEFT; RAIL SYSTEM AND FIRE SUPPRESSION NOZZLES IN FOREGROUND. - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 East, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

  13. Topography of whisking II: interaction of whisker and pad.

    PubMed

    Bermejo, R; Friedman, W; Zeigler, H P

    2005-09-01

    The peripheral effector system mediating rodent whisking produces protraction/retraction movements of the whiskers and translation movements of the collagenous mystacial pad. To examine the interaction of these movements during whisking in air we used high-resolution, optoelectronic methods for two-dimensional monitoring of whisker and pad movements in head-fixed rats. Under these testing conditions (1) whisker movements on the same side of the face are synchronous and of similar amplitude; (2) pad movements exhibit the characteristic 'exploratory' rhythm (6-12 Hz) of whisking but their movements often have a low frequency (1-2 Hz) component; (3) Pad movements occur in both antero-posterior and dorso-ventral planes but there are considerable variations in the amplitude and topography of movement parameters in the two planes. We conclude that (a) both whisker and pad receive input from a common central rhythm generator; (b) differences in whisker and pad amplitude and topography probably reflect differences in the biomechanical properties of the structures receiving that input; (c) pad movements make a significant contribution to the kinematics of whisking behavior and (d) the two-dimensional nature of pad translation movements significantly increases the rat's flexible control of its mobile sensor. PMID:16338829

  14. Public access to defibrillation (PAD): implementing a church program.

    PubMed

    Gilchrist, Jody

    2012-01-01

    For every minute without cardiopulmonary resuscitation and defibrillation, the odds of surviving cardiac arrest decrease by 7% to 10%. Churches can implement a public access to defibrillation (PAD) program and help save lives. This article outlines steps and resources for setting up a PAD program. PMID:22480085

  15. Implementing iPads in the Inclusive Classroom Setting

    ERIC Educational Resources Information Center

    Maich, Kimberly; Hall, Carmen

    2016-01-01

    This column provides practical suggestions to help guide teachers in utilizing classroom sets of iPads. Following a brief introduction to tablet technology in inclusive classrooms and the origin of these recommendations from a case study focus group, important elements of setting up classroom iPad use, from finding funding to teaching apps, are…

  16. Rod-like cholesterol micelles in aqueous solution studied using polarized and depolarized dynamic light scattering.

    PubMed Central

    Castanho, M A; Brown, W; Prieto, M J

    1992-01-01

    Micelles of cholesterol in aqueous solution have been investigated using polarized and depolarized dynamic light scattering. They are shown to be highly extended and characterized by a narrow size distribution. It is shown that a rod-like model is applicable with length, L = 580 nm. Determination of the rotational diffusion coefficient by analysis of the autocorrelation function gave a value of theta = 150 s-1, which is close to the calculated value for the rod with this dimension. Depolarized dynamic light scattering measurements as a function of angle gave a value of 110 s-1. PMID:1489905

  17. Open Vehicle Sketch Pad Aircraft Modeling Strategies

    NASA Technical Reports Server (NTRS)

    Hahn, Andrew S.

    2013-01-01

    Geometric modeling of aircraft during the Conceptual design phase is very different from that needed for the Preliminary or Detailed design phases. The Conceptual design phase is characterized by the rapid, multi-disciplinary analysis of many design variables by a small engineering team. The designer must walk a line between fidelity and productivity, picking tools and methods with the appropriate balance of characteristics to achieve the goals of the study, while staying within the available resources. Identifying geometric details that are important, and those that are not, is critical to making modeling and methodology choices. This is true for both the low-order analysis methods traditionally used in Conceptual design as well as the highest-order analyses available. This paper will highlight some of Conceptual design's characteristics that drive the designer s choices as well as modeling examples for several aircraft configurations using the open source version of the Vehicle Sketch Pad (Open VSP) aircraft Conceptual design geometry modeler.

  18. Launch Pad Flame Trench Refractory Materials

    NASA Technical Reports Server (NTRS)

    Calle, Luz M.; Hintze, Paul E.; Parlier, Christopher R.; Bucherl, Cori; Sampson, Jeffrey W.; Curran, Jerome P.; Kolody, Mark; Perusich, Steve; Whitten, Mary

    2010-01-01

    The launch complexes at NASA's John F. Kennedy Space Center (KSC) are critical support facilities for the successful launch of space-based vehicles. These facilities include a flame trench that bisects the pad at ground level. This trench includes a flame deflector system that consists of an inverted, V-shaped steel structure covered with a high temperature concrete material five inches thick that extends across the center of the flame trench. One side of the "V11 receives and deflects the flames from the orbiter main engines; the opposite side deflects the flames from the solid rocket boosters. There are also two movable deflectors at the top of the trench to provide additional protection to shuttle hardware from the solid rocket booster flames. These facilities are over 40 years old and are experiencing constant deterioration from launch heat/blast effects and environmental exposure. The refractory material currently used in launch pad flame deflectors has become susceptible to failure, resulting in large sections of the material breaking away from the steel base structure and creating high-speed projectiles during launch. These projectiles jeopardize the safety of the launch complex, crew, and vehicle. Post launch inspections have revealed that the number and frequency of repairs, as well as the area and size of the damage, is increasing with the number of launches. The Space Shuttle Program has accepted the extensive ground processing costs for post launch repair of damaged areas and investigations of future launch related failures for the remainder of the program. There currently are no long term solutions available for Constellation Program ground operations to address the poor performance and subsequent failures of the refractory materials. Over the last three years, significant liberation of refractory material in the flame trench and fire bricks along the adjacent trench walls following Space Shuttle launches have resulted in extensive investigations of

  19. Metal pad instabilities in liquid metal batteries.

    PubMed

    Zikanov, Oleg

    2015-12-01

    A mechanical analogy is used to analyze the interaction between the magnetic field, electric current, and deformation of interfaces in liquid metal batteries. In the framework of a low-mode, nondissipative, linear stability model, it is found that, during charging or discharging, a sufficiently large battery is prone to instabilities of two types. One is similar to the metal pad instability known to exist in the aluminum reduction cells. Another type is new. It is related to the destabilizing effect of the Lorentz force formed by the azimuthal magnetic field induced by the base current, and the current perturbations caused by the local variations of the thickness of the electrolyte layer. PMID:26764818

  20. Microneurovascular free digital pad transfer in the dog.

    PubMed

    Basher, A W; Fowler, J D; Bowen, C V; Clark, E G; Crosby, N L

    1990-01-01

    By cadaver dissections, the fifth digit of the canine hind limb was determined to have a consistent neurovascular anatomy, and therefore be a suitable donor for an axial pattern digital pad flap. The defined digital pad flap was transferred to the region of an excised metacarpal pad by microneurovascular anastomoses in five operations on four dogs. One flap failure was considered to result from failure of the venous anastomosis. In all four successful transfers, cutaneous sensation was reestablished on average in 78 days. There was histologic evidence of nerve regeneration across the anastomosis in one dog at week 24. The transferred pads of three dogs monitored for 15 months underwent hypertrophic changes. There were no complications in two active dogs. In one dog, superficial ulceration of a region of the flap adjacent to the pad required surgical revision. This dog continued to show mild lameness after daily runs of 3 to 4 km. PMID:1971973

  1. Pad printer for electronics. Final report

    SciTech Connect

    1998-05-01

    This is the Final report on DARPA-sponsored development Program Pad Printer for Electronics DE-FC04-95AL87486 which was initiated in February, 1995 and intended to run 24 months to February 1997. The Program has significant value to the Thick Film processing industry, an electronic manufacturing alternative for producing functional modules integrated at the multichip level. The result is highly reliable, high volumetric efficiency, subassemblies for military applications and for commercial applications in severe environments, such as automotive, portable communications, and bio-implantable devices. The program progressed quite satisfactorily through 19 months, when it encountered severe, non-technical, difficulties. Resolving these difficulties resulted in several months of delay in completing the Program, but resulted in only a trivial increase in total program cost and no increase in cost to the sponsor. The principle Objective of the Program was the development of a printing system -- machine and appropriate inks -- compatible with existing thick-film processing but offering a 5x improvement in line density. This objective has been met. The Pad Printer is capable of printing suitable inks in traces 25 g wide on 50g centers to a fired thickness of 3 {mu}; each of these parameters is roughly 1/5 the value of the current alternative, silk-screen printing. The available inks represent an assortment of conductor, dielectric, and insulator formulations and the knowledge developed permits extending this family of inks to new and diverse functional materials. An important secondary objective was maximum compatibility with existing Thick Film processing; the printer and ink systems may be substituted directly for the silk screen printers in existing processes. The Program reached or exceeded its other Technical Objectives in almost every case and, in those few instances where the objective was only partially met, work continues under private funding.

  2. Phrenic nerve afferent activation of neurons in the cat SI cerebral cortex.

    PubMed

    Davenport, Paul W; Reep, Roger L; Thompson, Floyd J

    2010-03-01

    Stimulation of respiratory afferents elicits neural activity in the somatosensory region of the cerebral cortex in humans and animals. Respiratory afferents have been stimulated with mechanical loads applied to breathing and electrical stimulation of respiratory nerves and muscles. It was hypothesized that stimulation of the phrenic nerve myelinated afferents will activate neurons in the 3a and 3b region of the somatosensory cortex. This was investigated in cats with electrical stimulation of the intrathoracic phrenic nerve and C(5) root of the phrenic nerve. The somatosensory cortical response to phrenic afferent stimulation was recorded from the cortical surface, contralateral to the phrenic nerve, ispilateral to the phrenic nerve and with microelectrodes inserted into the cortical site of the surface dipole. Short-latency, primary cortical evoked potentials (1 degrees CEP) were recorded with stimulation of myelinated afferents of the intrathoracic phrenic nerve in the contralateral post-cruciate gyrus of all animals (n = 42). The mean onset and peak latencies were 8.5 +/- 5.7 ms and 21.8 +/- 9.8 ms, respectively. The rostro-caudal surface location of the 1 degrees CEP was found between the rostral edge of the post-cruciate dimple (PCD) and the rostral edge of the ansate sulcus, medio-lateral location was between 2 mm lateral to the sagittal sulcus and the lateral end of the cruciate sulcus. Histological examination revealed that the 1 degrees CEP sites were recorded over areas 3a and 3b of the SI somatosensory cortex. Intracortical activation of 16 neurons with two patterns of neural activity was recorded: (1) short-latency, short-duration activation of neurons and (2) long-latency, long-duration activation of neurons. Short-latency neurons had a mean onset latency of 10.4 +/- 3.1 ms and mean burst duration of 10.1 +/- 3.2 ms. The short-latency units were recorded at an average depth of 1.7 +/- 0.5 mm below the cortical surface. The long-latency neurons had a

  3. iPads in Breast Imaging – A Phantom Study

    PubMed Central

    Hammon, M.; Schlechtweg, P. M.; Schulz-Wendtland, R.; Uder, M.; Schwab, S. A.

    2014-01-01

    Introduction: Modern tablet PCs as the iPad are becoming more and more integrated into medicine. The aim of this study was to evaluate the display quality of iPads regarding digital mammography. Materials and Methods: Three experienced readers compared the display quality of the iPad 2 and 3 with a dedicated 10 megapixel (MP) mammography liquid crystal display (LCD) screen in consensus using the standardized Contrast Detail Mammography (CDMAM) phantom. Phantom fields without agreement between the readers were classified as “uncertain”, correct 2 : 1 decisions were classified as “uncertain/readable”. In a second step display quality of the three reading devices was judged subjectively in a side by side comparison. Results: The 10 MP screen was superior to both iPads in 4 (phantom-)fields and inferior in 2 fields. Comparing the iPads, version 3 was superior in 4 fields and version 2 was superior in 1 field. However these differences were not significant. Total number of “uncertain” fields did not show significant differences. The number of “uncertain” fields was 15 with the 10 MP screen, 16 with the iPad 2 and 17 with the iPad 3 (p > 0.05), the number of “uncertain/readable” fields was 4, 7 and 8, respectively. Subjective image quality of the iPad 3 and the 10 MP screen was rated superior to the iPad 2. Conclusion: The evaluated iPads, especially in version 3, seem to be adequate to display mammograms in a diagnostic quality and thus could be useful e.g. for patient consultation, clinical demonstration or educational and teaching purposes. However primary mammogram reading should still be performed on dedicated large sized reading screens. PMID:24741126

  4. Binocular iPad treatment for amblyopia in preschool children

    PubMed Central

    Birch, Eileen E.; Li, Simone L.; Jost, Reed M.; Morale, Sarah E.; De La Cruz, Angie; Stager, David; Dao, Lori; Stager, David R.

    2014-01-01

    Background Recent experimental evidence supports a role for binocular visual experience in the treatment of amblyopia. The purpose of this study was to determine whether repeated binocular visual experience with dichoptic iPad games could effectively treat amblyopia in preschool children. Methods A total of 50 consecutive amblyopic preschool children 3–6.9 years of age were assigned to play sham iPad games (first 5 children) or binocular iPad games (n = 45) for at least 4 hours per week for 4 weeks. Thirty (67%) children in the binocular iPad group and 4 (80%) in the sham iPad group were also treated with patching at a different time of day. Visual acuity and stereoacuity were assessed at baseline, at 4 weeks, and at 3 months after the cessation of game play. Results The sham iPad group had no significant improvement in visual acuity (t4 = 0.34, P = 0.75). In the binocular iPad group, mean visual acuity (plus or minus standard error) improved from 0.43 ± 0.03 at baseline to 0.34 ± 0.03 logMAR at 4 weeks (n = 45; paired t44 = 4.93; P < 0.0001). Stereoacuity did not significantly improve (t44 = 1.35, P = 0.18). Children who played the binocular iPad games for ≥8 hours (≥50% compliance) had significantly more visual acuity improvement than children who played 0–4 hours (t43 = 4.21, P = 0.0001). Conclusions Repeated binocular experience, provided by dichoptic iPad game play, was more effective than sham iPad game play as a treatment for amblyopia in preschool children. PMID:25727578

  5. On the basis of delayed depolarization and its role in repetitive firing of Rohon-Beard neurones in Xenopus tadpoles.

    PubMed Central

    Spitzer, N C

    1984-01-01

    A delayed depolarization following the impulse can be recorded intracellularly from mature Rohon-Beard neurones in the spinal cord of Xenopus tadpoles, in response both to brief intracellularly injected current pulses and to antidromic stimulation. Evidence is presented suggesting that this delayed depolarization is unlikely to be due to the action of a chemical synapse, activation of a voltage-dependent conductance in the cell body, increased extracellular potassium, or electrotonic coupling. Hyperpolarization of the cell body during antidromic stimulation eliminates the action potential normally generated there, and reveals an impulse arising at some distance along a neurite. When an action potential is produced in the cell body, its repolarizing phase sculpts a delayed depolarization from this impulse in the neurite. The depolarization is enhanced by pressure applied to the neurites near the cell body, presumably by reducing the distal spread of current, and yields multiple action potentials. Although long current pulses usually produce only a single spike, small quantities of La3+ enhance the size of the depolarization and cause repetitive firing. The relation of impulse frequency to injected current shows a non-linearity consistent with the summation of the delayed depolarization and the depolarization by the injected current. The non-linearity is eliminated upon removal of delayed depolarization by hyperpolarizing current pulses injected after each impulse. The enhancement of the depolarization by La3+ is not the only cause of repetitive firing; La3+ also produces an effective reduction in conductance for outward currents. This depolarization may play a role in the normal firing behaviour of Rohon-Beard neurones; when repetitive firing results naturally in response to long current pulses the delayed depolarization is observed to be large. Images Plate 1 PMID:6512703

  6. Afferent fibres from pulmonary arterial baroreceptors in the left cardiac sympathetic nerve of the cat

    PubMed Central

    Nishi, K.; Sakanashi, M.; Takenaka, F.

    1974-01-01

    1. Afferent discharges were recorded from the left cardiac sympathetic nerve or the third sympathetic ramus communicans of anaesthetized cats. Twenty-one single units with baroreceptor activity were obtained. 2. The receptors of each unit were localized to the extrapulmonary part of the pulmonary artery, determined by direct mechanical probing of the wall of the pulmonary artery after death of the animals. Conduction velocity of the fibres ranged from 2·5 to 15·7 m/sec. 3. Afferent discharges occurred irregularly under artificial ventilation. The impulse activity was increased when pulmonary arterial pressure was raised by an intravenous infusion of Locke solution, or by occlusion of lung roots, and decreased by bleeding the animal from the femoral artery. 4. Above a threshold pressure, discharges occurred synchronously with the systolic pressure pulse in the pulmonary artery. A progressive further rise in pressure did not produce an increase in the number of impulses per heart beat. Occlusion of lung roots initially elicited a burst of discharges but the number of impulses for each cardiac cycle gradually decreased. 5. The receptors responded to repetitive mechanical stimuli up to a frequency of 10/sec, but failed to respond to stimuli delivered at 20/sec. 6. The results provide further evidence for the presence of afferent fibres in the cardiac sympathetic nerve. These afferent fibres are likely to provide the spinal cord with specific information only on transient changes in pulmonary arterial pressure. PMID:4850456

  7. Differential Role of Inhibition in Habituation of Two Independent Afferent Pathways to a Common Motor Output

    ERIC Educational Resources Information Center

    Bristol, Adam S.; Carew, Thomas J.

    2005-01-01

    Many studies of the neural mechanisms of learning have focused on habituation, a simple form of learning in which a response decrements with repeated stimulation. In the siphon-elicited siphon withdrawal reflex (S-SWR) of the marine mollusk "Aplysia," the prevailing view is that homosynaptic depression of primary sensory afferents underlies…

  8. Identification of bladder and colon afferents in the nodose ganglia of male rats.

    PubMed

    Herrity, April N; Rau, Kristofer K; Petruska, Jeffrey C; Stirling, David P; Hubscher, Charles H

    2014-11-01

    The sensory neurons innervating the urinary bladder and distal colon project to similar regions of the central nervous system and often are affected simultaneously by various diseases and disorders, including spinal cord injury. Anatomical and physiological commonalities between the two organs involve the participation of shared spinally derived pathways, allowing mechanisms of communication between the bladder and colon. Prior electrophysiological data from our laboratory suggest that the bladder also may receive sensory innervation from a nonspinal source through the vagus nerve, which innervates the distal colon as well. The present study therefore aimed to determine whether anatomical evidence exists for vagal innervation of the male rat urinary bladder and to assess whether those vagal afferents also innervate the colon. Additionally, the relative contribution to bladder and colon sensory innervation of spinal and vagal sources was determined. By using lipophilic tracers, neurons that innervated the bladder and colon in both the nodose ganglia (NG) and L6/S1 and L1/L2 dorsal root ganglia (DRG) were quantified. Some single vagal and spinal neurons provided dual innervation to both organs. The proportions of NG afferents labeled from the bladder did not differ from spinal afferents labeled from the bladder when considering the collective population of total neurons from either group. Our results demonstrate evidence for vagal innervation of the bladder and colon and suggest that dichotomizing vagal afferents may provide a neural mechanism for cross-talk between the organs. PMID:24845615

  9. Inhibitory mechanisms following electrical stimulation of tendon and cutaneous afferents in the lower limb.

    PubMed

    Khan, Serajul I; Burne, John A

    2010-01-13

    Electrical stimulation of the Achilles tendon (TES) produced strong reflex depression (duration>250 ms) of a small background contraction in both heads of gastrocnemius (GA) via large diameter electrodes localized to the tendon. The inhibitory responses were produced without electrical (M wave) or mechanical (muscle twitch) signs of direct muscle stimulation. In this study, the contribution of presynaptic and postsynaptic mechanisms to the depression was investigated by studying conditioning effects of tendon afferent stimulation on the mechanical tendon reflex (TR) and magnetic motor evoked potential (MEP). TES completely inhibited the TR over an ISI of 300 ms that commenced before and continued during and after the period of voluntary EMG depression. Tendon afferent conditioning stimuli also partially inhibited the MEP, but over a short time course confined to the period of voluntary EMG depression. The strength and extended time course of tendon afferent conditioning of the TR and its failure to produce a similar depression of the MEP are consistent with a mechanism involving presynaptic inhibition of Ia terminals. Cutaneous (sural nerve) afferent conditioning partially inhibited the TR and MEP over a short time course (ISI <100 ms) resembling the inhibition seen in the voluntary EMG. This was consistent with the postsynaptic origin of cutaneous inhibition of the motoneurons. PMID:19850015

  10. Afferent control of locomotor CPG: insights from a simple neuromechanical model.

    PubMed

    Markin, Sergey N; Klishko, Alexander N; Shevtsova, Natalia A; Lemay, Michel A; Prilutsky, Boris I; Rybak, Ilya A

    2010-06-01

    A simple neuromechanical model has been developed that describes a spinal central pattern generator (CPG) controlling the locomotor movement of a single-joint limb via activation of two antagonist (flexor and extensor) muscles. The limb performs rhythmic movements under control of the muscular, gravitational and ground reaction forces. Muscle afferents provide length-dependent (types Ia and II) and force-dependent (type Ib from the extensor) feedback to the CPG. We show that afferent feedback adjusts CPG operation to the kinematics and dynamics of the limb providing stable "locomotion." Increasing the supraspinal drive to the CPG increases locomotion speed by reducing the duration of stance phase. We show that such asymmetric, extensor-dominated control of locomotor speed (with relatively constant swing duration) is provided by afferent feedback independent of the asymmetric rhythmic pattern generated by the CPG alone (in "fictive locomotion" conditions). Finally, we demonstrate the possibility of reestablishing stable locomotion after removal of the supraspinal drive (associated with spinal cord injury) by increasing the weights of afferent inputs to the CPG, which is thought to occur following locomotor training. PMID:20536917

  11. A dynamical systems analysis of afferent control in a neuromechanical model of locomotion. I. Rhythm generation

    PubMed Central

    Spardy, Lucy E.; Markin, Sergey N.; Shevtsova, Natalia A.; Prilutsky, Boris I.; Rybak, Ilya A.; Rubin, Jonathan E.

    2012-01-01

    Locomotion in mammals is controlled by a spinal central pattern generator (CPG) coupled to a biomechanical limb system, with afferent feedback to the spinal circuits and CPG closing the control loop. We have considered a simplified model of this system, in which the CPG establishes a rhythm when a supra-spinal activating drive is present and afferent signals from a single-joint limb feed back to affect CPG operation. Using dynamical systems methods, in a series of two papers, we analyze the mechanisms by which this model produces oscillations, and the characteristics of these oscillations, in the closed and open loop regimes. In this first paper, we analyze the phase transition mechanisms operating within the CPG and use the results to explain how afferent feedback allows oscillations to occur at a wider range of drive values to the CPG than the range over which oscillations occur in the CPG without feedback and to comment on why stronger feedback leads to faster oscillations. Linking these transitions to structure in the phase plane associated with the limb segment clarifies how increased weights of afferent feedback to the CPG can restore locomotion after removal of supra-spinal drive to simulate spinal cord injury. PMID:22058274

  12. A dynamical systems analysis of afferent control in a neuromechanical model of locomotion: I. Rhythm generation.

    PubMed

    Spardy, Lucy E; Markin, Sergey N; Shevtsova, Natalia A; Prilutsky, Boris I; Rybak, Ilya A; Rubin, Jonathan E

    2011-12-01

    Locomotion in mammals is controlled by a spinal central pattern generator (CPG) coupled to a biomechanical limb system, with afferent feedback to the spinal circuits and CPG closing the control loop. We have considered a simplified model of this system, in which the CPG establishes a rhythm when a supra-spinal activating drive is present and afferent signals from a single-joint limb feed back to affect CPG operation. Using dynamical system methods, in a series of two papers we analyze the mechanisms by which this model produces oscillations, and the characteristics of these oscillations, in the closed- and open-loop regimes. In this first paper, we analyze the phase transition mechanisms operating within the CPG and use the results to explain how afferent feedback allows oscillations to occur at a wider range of drive values to the CPG than the range over which oscillations occur in the CPG without feedback, and then to comment on why stronger feedback leads to faster oscillations. Linking these transitions to structures in the phase plane associated with the limb segment clarifies how increased weights of afferent feedback to the CPG can restore locomotion after removal of supra-spinal drive to simulate spinal cord injury. PMID:22058274

  13. Single tactile afferents outperform human subjects in a vibrotactile intensity discrimination task.

    PubMed

    Arabzadeh, Ehsan; Clifford, Colin W G; Harris, Justin A; Mahns, David A; Macefield, Vaughan G; Birznieks, Ingvars

    2014-11-15

    We simultaneously compared the sensitivity of single primary afferent neurons supplying the glabrous skin of the hand and the psychophysical amplitude discrimination thresholds in human subjects for a set of vibrotactile stimuli delivered to the receptive field. All recorded afferents had a dynamic range narrower than the range of amplitudes across which the subjects could discriminate. However, when the vibration amplitude was chosen to be within the steepest part of the afferent's stimulus-response function the response of single afferents, defined as the spike count over the vibration duration (500 ms), was often more sensitive in discriminating vibration amplitude than the perceptual judgment of the participants. We quantified how the neuronal performance depended on the integration window: for short windows the neuronal performance was inferior to the performance of the subject. The neuronal performance progressively improved with increasing spike count duration and reached a level significantly above that of the subjects when the integration window was 250 ms or longer. The superiority in performance of individual neurons over observers could reflect a nonoptimal integration window or be due to the presence of noise between the sensory periphery and the cortical decision stage. Additionally, it could indicate that the range of perceptual sensitivity comes at the cost of discrimination through pooling across neurons with different response functions. PMID:25143540

  14. A binocular pupil model for simulation of relative afferent pupil defect, RAPD.

    PubMed

    Privitera, Claudio M; Stark, Lawrence W

    2004-01-01

    The human pupil is an important element studied in many clinical procedures. The binocular pupil model presented has a topology encompassing much of the complexity of the pupil system neurophysiology. The dynamic parameters of the model were matched against pupil experiments under multiple conditions. It simulates responses to the swinging flashlight test for different degrees of relative afferent pupil defects, RAPD. PMID:17271776

  15. Modeling the spinal pudendo-vesical reflex for bladder control by pudendal afferent stimulation.

    PubMed

    McGee, Meredith J; Grill, Warren M

    2016-06-01

    Electrical stimulation of the pudendal nerve (PN) is a promising approach to restore continence and micturition following bladder dysfunction resulting from neurological disease or injury. Although the pudendo-vesical reflex and its physiological properties are well established, there is limited understanding of the specific neural mechanisms that mediate this reflex. We sought to develop a computational model of the spinal neural network that governs the reflex bladder response to PN stimulation. We implemented and validated a neural network architecture based on previous neuroanatomical and electrophysiological studies. Using synaptically-connected integrate and fire model neurons, we created a network model with realistic spiking behavior. The model produced expected sacral parasympathetic nucleus (SPN) neuron firing rates from prescribed neural inputs and predicted bladder activation and inhibition with different frequencies of pudendal afferent stimulation. In addition, the model matched experimental results from previous studies of temporal patterns of pudendal afferent stimulation and selective pharmacological blockade of inhibitory neurons. The frequency- and pattern-dependent effects of pudendal afferent stimulation were determined by changes in firing rate of spinal interneurons, suggesting that neural network interactions at the lumbosacral level can mediate the bladder response to different frequencies or temporal patterns of pudendal afferent stimulation. Further, the anatomical structure of excitatory and inhibitory interneurons in the network model was necessary and sufficient to reproduce the critical features of the pudendo-vesical reflex, and this model may prove useful to guide development of novel, more effective electrical stimulation techniques for bladder control. PMID:26968615

  16. Role of primary afferents in the developmental regulation of motor axon synapse numbers on Renshaw cells.

    PubMed

    Siembab, Valerie C; Gomez-Perez, Laura; Rotterman, Travis M; Shneider, Neil A; Alvarez, Francisco J

    2016-06-15

    Motor function in mammalian species depends on the maturation of spinal circuits formed by a large variety of interneurons that regulate motoneuron firing and motor output. Interneuron activity is in turn modulated by the organization of their synaptic inputs, but the principles governing the development of specific synaptic architectures unique to each premotor interneuron are unknown. For example, Renshaw cells receive, at least in the neonate, convergent inputs from sensory afferents (likely Ia) and motor axons, raising the question of whether they interact during Renshaw cell development. In other well-studied neurons, such as Purkinje cells, heterosynaptic competition between inputs from different sources shapes synaptic organization. To examine the possibility that sensory afferents modulate synaptic maturation on developing Renshaw cells, we used three animal models in which afferent inputs in the ventral horn are dramatically reduced (ER81(-/-) knockout), weakened (Egr3(-/-) knockout), or strengthened (mlcNT3(+/-) transgenic). We demonstrate that increasing the strength of sensory inputs on Renshaw cells prevents their deselection and reduces motor axon synaptic density, and, in contrast, absent or diminished sensory afferent inputs correlate with increased densities of motor axons synapses. No effects were observed on other glutamatergic inputs. We conclude that the early strength of Ia synapses influences their maintenance or weakening during later development and that heterosynaptic influences from sensory synapses during early development regulates the density and organization of motor inputs on mature Renshaw cells. J. Comp. Neurol. 524:1892-1919, 2016. © 2016 Wiley Periodicals, Inc. PMID:26660356

  17. A dynamical systems analysis of afferent control in a neuromechanical model of locomotion: I. Rhythm generation

    NASA Astrophysics Data System (ADS)

    Spardy, Lucy E.; Markin, Sergey N.; Shevtsova, Natalia A.; Prilutsky, Boris I.; Rybak, Ilya A.; Rubin, Jonathan E.

    2011-10-01

    Locomotion in mammals is controlled by a spinal central pattern generator (CPG) coupled to a biomechanical limb system, with afferent feedback to the spinal circuits and CPG closing the control loop. We have considered a simplified model of this system, in which the CPG establishes a rhythm when a supra-spinal activating drive is present and afferent signals from a single-joint limb feed back to affect CPG operation. Using dynamical system methods, in a series of two papers we analyze the mechanisms by which this model produces oscillations, and the characteristics of these oscillations, in the closed- and open-loop regimes. In this first paper, we analyze the phase transition mechanisms operating within the CPG and use the results to explain how afferent feedback allows oscillations to occur at a wider range of drive values to the CPG than the range over which oscillations occur in the CPG without feedback, and then to comment on why stronger feedback leads to faster oscillations. Linking these transitions to structures in the phase plane associated with the limb segment clarifies how increased weights of afferent feedback to the CPG can restore locomotion after removal of supra-spinal drive to simulate spinal cord injury.

  18. Stochastic resonance in the synaptic transmission between hair cells and vestibular primary afferents in development.

    PubMed

    Flores, A; Manilla, S; Huidobro, N; De la Torre-Valdovinos, B; Kristeva, R; Mendez-Balbuena, I; Galindo, F; Treviño, M; Manjarrez, E

    2016-05-13

    The stochastic resonance (SR) is a phenomenon of nonlinear systems in which the addition of an intermediate level of noise improves the response of such system. Although SR has been studied in isolated hair cells and in the bullfrog sacculus, the occurrence of this phenomenon in the vestibular system in development is unknown. The purpose of the present study was to explore for the existence of SR via natural mechanical-stimulation in the hair cell-vestibular primary afferent transmission. In vitro experiments were performed on the posterior semicircular canal of the chicken inner ear during development. Our experiments showed that the signal-to-noise ratio of the afferent multiunit activity from E15 to P5 stages of development exhibited the SR phenomenon, which was characterized by an inverted U-like response as a function of the input noise level. The inverted U-like graphs of SR acquired their higher amplitude after the post-hatching stage of development. Blockage of the synaptic transmission with selective antagonists of the NMDA and AMPA/Kainate receptors abolished the SR of the afferent multiunit activity. Furthermore, computer simulations on a model of the hair cell - primary afferent synapse qualitatively reproduced this SR behavior and provided a possible explanation of how and where the SR could occur. These results demonstrate that a particular level of mechanical noise on the semicircular canals can improve the performance of the vestibular system in their peripheral sensory processing even during embryonic stages of development. PMID:26926966

  19. Mitochondrial depolarization and electrophysiological changes during ischemia in the rabbit and human heart.

    PubMed

    Sulkin, Matthew S; Boukens, Bas J; Tetlow, Megan; Gutbrod, Sarah R; Ng, Fu Siong; Efimov, Igor R

    2014-10-15

    Instability of the inner mitochondrial membrane potential (ΔΨm) has been implicated in electrical dysfunction, including arrhythmogenesis during ischemia-reperfusion. Monitoring ΔΨm has led to conflicting results, where depolarization has been reported as sporadic and as a propagating wave. The present study was designed to resolve the aforementioned difference and determine the unknown relationship between ΔΨm and electrophysiology. We developed a novel imaging modality for simultaneous optical mapping of ΔΨm and transmembrane potential (Vm). Optical mapping was performed using potentiometric dyes on preparations from 4 mouse hearts, 14 rabbit hearts, and 7 human hearts. Our data showed that during ischemia, ΔΨm depolarization is sporadic and changes asynchronously with electrophysiological changes. Spatially, ΔΨm depolarization was associated with action potential duration shortening but not conduction slowing. Analysis of focal activity indicated that ΔΨm is not different within the myocardium where the focus originates compared with normal ventricular tissue. Overall, our data suggest that during ischemia, mitochondria maintain their function at the expense of sarcolemmal electrophysiology, but ΔΨm depolarization does not have a direct association to ischemia-induced arrhythmias. PMID:25128175

  20. Depolarization-induced release of amino acids from the vestibular nuclear complex.

    PubMed

    Godfrey, Donald A; Sun, Yizhe; Frisch, Christopher; Godfrey, Matthew A; Rubin, Allan M

    2012-04-01

    There is evidence from immunohistochemistry, quantitative microchemistry, and pharmacology for several amino acids as neurotransmitters in the vestibular nuclear complex (VNC), including glutamate, γ-aminobutyrate (GABA), and glycine. However, evidence from measurements of release has been limited. The purpose of this study was to measure depolarization-stimulated calcium-dependent release of amino acids from the VNC in brain slices. Coronal slices containing predominantly the VNC were prepared from rats and perfused with artificial cerebrospinal fluid (ACSF) in an interface chamber. Fluid was collected from the chamber just downstream from the VNC using a microsiphon. Depolarization was induced by 50 mM potassium in either control calcium and magnesium concentrations or reduced calcium and elevated magnesium. Amino acid concentrations in effluent fluid were measured by high performance liquid chromatography. Glutamate release increased fivefold during depolarization in control calcium concentration and twofold in low calcium/high magnesium. These same ratios were 6 and 1.5 for GABA, 2 and 1.3 for glycine, and 2 and 1.5 for aspartate. Differences between release in control and low calcium/high magnesium ACSF were statistically significant for glutamate, GABA, and glycine. Glutamine release decreased during and after depolarization, and taurine release slowly increased. No evidence for calcium-dependent release was found for serine, glutamine, alanine, threonine, arginine, taurine, or tyrosine. Our results support glutamate and GABA as major neurotransmitters in the VNC. They also support glycine as a neurotransmitter and some function for taurine. PMID:22147284

  1. Suppression of Ultracold Neutron Depolarization on Material Surfaces with Magnetic Holding Fields

    NASA Astrophysics Data System (ADS)

    Rios, Raymond

    2009-10-01

    Experiments involving polarized Ultracold Neutrons (UCN) for high precision measurements require the use of high Fermi potential materials with a low spin flip probability per bounce. Previous studies show that the spin flip probability for materials vary on the order of 10-3 to 10-6. In this study, the depolarization of UCN was measured within 1-m long, 2 3/4" diameter bare copper, electropolished copper, diamond-like carbon-coated copper, and stainless steel guide tubes as a function of the magnetic holding field. The UCN were trapped between a 6 Tesla solenoidal magnet and a copper plate. A series of Helmholtz coils produced a magnetic holding field over the length of the test guide at 10, 100, or 250 Gauss. The surface depolarization was observed to be suppressed at higher holding fields. These measurements will aid in the determination of an upper limit on depolarization of UCN in the UCNA beta asymmetry measurement at LANL and in understanding the mechanisms for depolarization in non-magnetic guides.

  2. Molecular anisotropy effects in carbon K-edge scattering: depolarized diffuse scattering and optical anisotropy

    SciTech Connect

    Stone, Kevin H.

    2014-07-14

    Some polymer properties, such as conductivity, are very sensitive to short- and intermediate-range orientational and positional ordering of anisotropic molecular functional groups, and yet means to characterize orientational order in disordered systems are very limited. We demonstrate that resonant scattering at the carbon K-edge is uniquely sensitive to short-range orientation correlations in polymers through depolarized scattering at high momentum transfers, using atactic polystyrene as a well-characterized test system. Depolarized scattering is found to coexist with unpolarized fluorescence, and to exhibit pronounced anisotropy. We also quantify the spatially averaged optical anisotropy from low-angle reflectivity measurements, finding anisotropy consistent with prior visible, x-ray absorption, and theoretical studies. The average anisotropy is much smaller than that in the depolarized scattering and the two have different character. Both measurements exhibit clear spectral signatures from the phenyl rings and the polyethylene-like backbone. Discussion focuses on analysis considerations and prospects for using this depolarized scattering for studies of disorder in soft condensed matter.

  3. Spike after-depolarization and burst generation in adult rat hippocampal CA1 pyramidal cells.

    PubMed Central

    Jensen, M S; Azouz, R; Yaari, Y

    1996-01-01

    1. Intracellular recordings in adult rat hippocampal slices were used to investigate the properties and origins of intrinsically generated bursts in the somata of CA1 pyramidal cells (PCs). The CA1 PCs were classified as either non-bursters or bursters according to the firing patterns evoked by intrasomatically applied long ( > or = 100 ms) depolarizing current pulses. Non-bursters generated stimulus-graded trains of independent action potentials, whereas bursters generated clusters of three or more closely spaced spikes riding on a distinct depolarizing envelope. 2. In all PCs fast spike repolarization was incomplete and ended at a potential approximately 10 mV more positive than resting potential. Solitary spikes were followed by a distinct after-depolarizing potential (ADP) lasting 20-40 ms. The ADP in most non-bursters declined monotonically to baseline ('passive' ADP), whereas in most bursters it remained steady or even re-depolarized before declining to baseline ('active' ADP). 3. Active, but not passive, ADPs were associated with an apparent increase in input conductance. They were maximal in amplitude when the spike was evoked from resting potential and were reduced by mild depolarization or hyperpolarization (+/- 2 mV). 4. Evoked and spontaneous burst firing was sensitive to small changes in membrane potential. In most cases maximal bursts were generated at resting potential and were curtailed by small depolarizations or hyperpolarizations (+/- 5 mV). 5. Bursts comprising clusters of spikelets ('d-spikes') were observed in 12% of the bursters. Some of the d-spikes attained threshold for triggering full somatic spikes. Gradually hyperpolarizing these neurones blocked somatic spikes before blocking d-spikes, suggesting that the latter are generated at more remote sites. 6. The data suggest that active ADPs and intrinsic bursts in the somata of adult CA1 PCs are generated by a slow, voltage-gated inward current. Bursts arise in neurones in which this current

  4. Depolarization of mitochondria in neurons promotes activation of nitric oxide synthase and generation of nitric oxide.

    PubMed

    Katakam, Prasad V G; Dutta, Somhrita; Sure, Venkata N; Grovenburg, Samuel M; Gordon, Angellica O; Peterson, Nicholas R; Rutkai, Ibolya; Busija, David W

    2016-05-01

    The diverse signaling events following mitochondrial depolarization in neurons are not clear. We examined for the first time the effects of mitochondrial depolarization on mitochondrial function, intracellular calcium, neuronal nitric oxide synthase (nNOS) activation, and nitric oxide (NO) production in cultured neurons and perivascular nerves. Cultured rat primary cortical neurons were studied on 7-10 days in vitro, and endothelium-denuded cerebral arteries of adult Sprague-Dawley rats were studied ex vivo. Diazoxide and BMS-191095 (BMS), activators of mitochondrial KATP channels, depolarized mitochondria in cultured neurons and increased cytosolic calcium levels. However, the mitochondrial oxygen consumption rate was unaffected by mitochondrial depolarization. In addition, diazoxide and BMS not only increased the nNOS phosphorylation at positive regulatory serine 1417 but also decreased nNOS phosphorylation at negative regulatory serine 847. Furthermore, diazoxide and BMS increased NO production in cultured neurons measured with both fluorescence microscopy and electron spin resonance spectroscopy, which was sensitive to inhibition by the selective nNOS inhibitor 7-nitroindazole (7-NI). Diazoxide also protected cultured neurons against oxygen-glucose deprivation, which was blocked by NOS inhibition and rescued by NO donors. Finally, BMS induced vasodilation of endothelium denuded, freshly isolated cerebral arteries that was diminished by 7-NI and tetrodotoxin. Thus pharmacological depolarization of mitochondria promotes activation of nNOS leading to generation of NO in cultured neurons and endothelium-denuded arteries. Mitochondrial-induced NO production leads to increased cellular resistance to lethal stress by cultured neurons and to vasodilation of denuded cerebral arteries. PMID:26945078

  5. Dual depolarization responses generated within the same lateral septal neurons by TRPC4-containing channels

    PubMed Central

    Tian, Jinbin; Thakur, Dhananjay P.; Lu, Yungang; Zhu, Yingmin; Freichel, Marc; Flockerzi, Veit

    2013-01-01

    In the central nervous system, canonical transient receptor potential (TRPC) channels have been implicated in mediating neuronal excitation induced by stimulating metabotropic receptors, including group 1 metabotropic glutamate receptors (mGluRs). Lateral septal (LS) neurons express high levels of TRPC4 and group I mGluRs. However, to what extent native TRPC4-containing channels (TRPC4-cc) are activated as well as the impact of different levels of TRPC4-cc activation on neuronal excitability remain elusive. Here, we report that stimulating LS neurons with group I mGluR agonist, (S)-3,5-DHPG, causes either an immediate increase in firing rate or an initial burst followed by a pause of firing, which can be correlated with below-threshold-depolarization (BTD) or above-threshold-plateau-depolarization (ATPD), respectively, in whole-cell recordings. The early phase of BTD and the entire ATPD are completely absent in neurons from TRPC4−/− mice. Moreover, in the same LS neurons, BTD can be converted to ATPD at more depolarized potentials or with a brief current injection, suggesting that BTD and ATPD may represent partial and full activations of TRPC4-cc, respectively. We show that coincident mGluR stimulation and depolarization is required to evoke strong TRPC4-cc current, and Na+ and Ca2+ influx, together with dynamic changes of intracellular Ca2+, are essential for ATPD induction. Our results suggest that TRPC4-cc integrates metabotropic receptor stimulation with intracellular Ca2+ signals to generate two interconvertible depolarization responses to affect excitability of LS neurons in distinct fashions. PMID:24121765

  6. Nuclear depolarization and absolute sensitivity in magic-angle spinning cross effect dynamic nuclear polarization.

    PubMed

    Mentink-Vigier, Frédéric; Paul, Subhradip; Lee, Daniel; Feintuch, Akiva; Hediger, Sabine; Vega, Shimon; De Paëpe, Gaël

    2015-09-14

    Over the last two decades solid state Nuclear Magnetic Resonance has witnessed a breakthrough in increasing the nuclear polarization, and thus experimental sensitivity, with the advent of Magic Angle Spinning Dynamic Nuclear Polarization (MAS-DNP). To enhance the nuclear polarization of protons, exogenous nitroxide biradicals such as TOTAPOL or AMUPOL are routinely used. Their efficiency is usually assessed as the ratio between the NMR signal intensity in the presence and the absence of microwave irradiation εon/off. While TOTAPOL delivers an enhancement εon/off of about 60 on a model sample, the more recent AMUPOL is more efficient: >200 at 100 K. Such a comparison is valid as long as the signal measured in the absence of microwaves is merely the Boltzmann polarization and is not affected by the spinning of the sample. However, recent MAS-DNP studies at 25 K by Thurber and Tycko (2014) have demonstrated that the presence of nitroxide biradicals combined with sample spinning can lead to a depolarized nuclear state, below the Boltzmann polarization. In this work we demonstrate that TOTAPOL and AMUPOL both lead to observable depolarization at ≈110 K, and that the magnitude of this depolarization is radical dependent. Compared to the static sample, TOTAPOL and AMUPOL lead, respectively, to nuclear polarization losses of up to 20% and 60% at a 10 kHz MAS frequency, while Trityl OX63 does not depolarize at all. This experimental work is analyzed using a theoretical model that explains how the depolarization process works under MAS and gives new insights into the DNP mechanism and into the spin parameters, which are relevant for the efficiency of a biradical. In light of these results, the outstanding performance of AMUPOL must be revised and we propose a new method to assess the polarization gain for future radicals. PMID:26235749

  7. Optogenetic activation of mechanically insensitive afferents in mouse colorectum reveals chemosensitivity.

    PubMed

    Feng, Bin; Joyce, Sonali C; Gebhart, G F

    2016-05-15

    The sensory innervation of the distal colorectum includes mechanically insensitive afferents (MIAs; ∼25%), which acquire mechanosensitivity in persistent visceral hypersensitivity and thus generate de novo input to the central nervous system. We utilized an optogenetic approach to bypass the process of transduction (generator potential) and focus on transformation (spike initiation) at colorectal MIA sensory terminals, which is otherwise not possible in typical functional studies. From channelrhodopsin2-expressing mice (driven by Advillin-Cre), the distal colorectum with attached pelvic nerve was harvested for ex vivo single-fiber recordings. Afferent receptive fields (RFs) were identified by electrical stimulation and tested for response to mechanical stimuli (probing, stroking, and stretch), and afferents were classified as either MIAs or mechanosensitive afferents (MSAs). All MIA and MSA RFs were subsequently stimulated optically and MIAs were also tested for activation/sensitization with inflammatory soup (IS), acidic hypertonic solution (AHS), and/or bile salts (BS). Responses to pulsed optical stimuli (1-10 Hz) were comparable between MSAs and MIAs whereas 43% of MIAs compared with 86% of MSAs responded tonically to stepped optical stimuli. Tonic-spiking MIAs responded preferentially to AHS (an osmotic stimulus) whereas non-tonic-spiking MIAs responded to IS (an inflammatory stimulus). A significant proportion of MIAs were also sensitized by BS. These results reveal transformation as a critical factor underlying the differences between MIAs (osmosensors vs. inflammatory sensors), revealing a previously unappreciated heterogeneity of MIA endings. The current study draws attention to the sensory encoding of MIA nerve endings that likely contribute to afferent sensitization and thus have important roles in visceral pain. PMID:26950857

  8. [The supinator fat pad in fractures of the elbow joint].

    PubMed

    Schunk, K; Grossholz, M; Schild, H

    1989-03-01

    The position of the supinator fat pad is regarded as a valuable sign in fractures of the elbow. In our patients the pad was visible in 277 out of 337 cases (82%). The sign was positive in only 27 out of 55 proximal fractures of the radius (sensitivity 0.49). There was no correlation between the severity of the fracture and the sign. There was marked variation in the distance between the pad and the radius, depending on age, build and projection. Our results indicate that the sign is not suitable for the diagnosis of fracture of the elbow. PMID:2538879

  9. Paclitaxel-induced increase in NCX activity in subpopulations of nociceptive afferents: A protective mechanism against chemotherapy-induced peripheral neuropathy?

    PubMed

    Yilmaz, Eser; Gold, Michael S

    2016-07-01

    We recently demonstrated, in a rat model of chemotherapy-induced peripheral neuropathy (CIPN), that there is a significant decrease in the duration of the depolarization-evoked Ca(2+) transient in isolated somata of putative nociceptive afferents innervating the glabrous skin of the hindpaw, but no change in transient magnitude or the resting concentration of intracellular Ca(2+) ([Ca(2+)]i). Because the Na(+)-Ca(2+) exchanger (NCX) only contributes to the regulation of the duration of the evoked Ca(2+) transient, in putative nociceptive dorsal root ganglion (DRG) neurons, we hypothesized that an increase in NCX activity underlies the CIPN-induced change in this subpopulation of neurons. Acutely dissociated retrogradely labeled sensory neurons from naïve, vehicle-, and paclitaxel-treated rats were studied with fura-2 based Ca(2+) imaging. There was no difference in the relative level of NCX activity between glabrous neurons from paclitaxel-treated or control rats. However, in contrast to the relatively large and long lasting Ca(2+) transients needed to evoke NCX activity in neurons from naïve rats, there was evidence of resting NCX activity in glabrous neurons from both vehicle- and paclitaxel-treated rats. More interestingly, there was a paclitaxel-induced increase in NCX activity in putative nociceptive neurons innervating the thigh, neurons in which there is no evidence of a change in the depolarization-induced Ca(2+) transient, or a body site in which there was a change in nociceptive threshold. Furthermore, while the majority of NCX activity in glabrous neurons is sensitive to the NCX3-preferring blocker KB-R7943, the increase in NCX activity in thigh neurons was resistant to KB-R7943 but sensitive to the NCX1-preferring blocker SEA0400. These results suggest that a mechanism(s) other than NCX underlies the paclitaxel-induced decrease in the duration of the evoked Ca(2+) transient in putative nociceptive glabrous skin neurons. However, the compensatory

  10. Evidence for two mechanisms of depolarization associated with alpha 1-adrenoceptor activation in the rat anococcygeus muscle.

    PubMed

    Byrne, N G; Large, W A

    1985-11-01

    Membrane potential responses in the rat isolated anococcygeus to bath-applied noradrenaline and field stimulation have been investigated by use of intracellular microelectrode and combined extracellular electrical and mechanical (sucrose gap) recording techniques. Intracellular recordings were made usually from tissues immobilized with hypertonic Krebs solution. Bath-application of noradrenaline produced depolarizations which consisted of two components; an initial 'fast' phase which peaked within 1-2 s and which was followed by a 'slow' sustained depolarization. Both components were concentration-dependent. Noradrenaline could also evoke oscillations in membrane potential which, unlike the 'fast' component of depolarization, were prevented by conditioning hyperpolarization of the membrane and were evoked by direct membrane depolarization with externally applied current pulses. Thus, the oscillations are voltage-dependent phenomena. Replacement of the external NaCl of the Krebs solution with an equimolar amount of Na benzenesulphonate abolished the noradrenaline-evoked 'fast' depolarization while the 'slow' phase was unaffected. This suggests that two mechanisms of depolarization are activated in this muscle by the bath-application of noradrenaline. The adrenergic excitatory junction potential was also abolished in Na benzenesulphonate. Prazosin reduced both the 'fast' and 'slow' components of depolarization produced by noradrenaline indicating their mediation by alpha 1-adrenoceptors. The membrane potential (-29 mV) at the maximum amplitude of the 'fast' depolarization was similar to the equilibrium potential (-27 mV) for the depolarization evoked by ionophoretically applied noradrenaline and which was obtained by extrapolation from the relationship between amplitude of the ionophoretic response and membrane potential displacement in the partition chamber. These results suggest that the 'fast' depolarization and the ionophoretic response are due to an increased

  11. Intraspinal sprouting of unmyelinated pelvic afferents after complete spinal cord injury is correlated with autonomic dysreflexia induced by visceral pain

    PubMed Central

    Hou, Shaoping; Duale, Hanad; Rabchevsky, Alexander G.

    2012-01-01

    Autonomic dysreflexia is a potentially life-threatening hypertensive syndrome following high thoracic (T) spinal cord injury (SCI). It is commonly triggered by noxious pelvic stimuli below the injury site that correlates with increased sprouting of primary afferent C-fibers into the lumbosacral spinal cord. We have recently demonstrated that injury-induced plasticity of lumbosacral propriospinal neurons, which relay pelvic visceral sensations to thoracolumbar sympathetic preganglionic neurons, is also correlated with the development of this syndrome. To determine the phenotype of pelvic afferent fiber sprouts after SCI, cholera toxin subunit beta (CTb) was injected into the distal colon 2 weeks post T4 transection/sham to label colonic visceral afferents. After 1 week transport, the lumbosacral spinal cords were cryosectioned and immunohistochemically stained for CTb, the nociceptive-specific marker calcitonin gene-related peptide (CGRP), and the myelinated fiber marker RT97. Quantitative analysis showed that the density of CGRP+ afferent fibers was significantly increased in the L6/S1 dorsal horns of T4-transected versus sham rats, whereas RT97+ afferent fiber density showed no change. Importantly, CTb-labeled pelvic afferent fibers were co-localized with CGRP+ fibers, but not with RT97+ fibers. These results suggest that the sprouting of unmyelinated nociceptive pelvic afferents following high thoracic SCI, but not myelinated fibers, contributes to hypertensive autonomic dysreflexia induced by pelvic visceral pain. PMID:19146928

  12. Different types of spinal afferent nerve endings in stomach and esophagus identified by anterograde tracing from dorsal root ganglia.

    PubMed

    Spencer, Nick J; Kyloh, Melinda; Beckett, Elizabeth A; Brookes, Simon; Hibberd, Tim

    2016-10-15

    In visceral organs of mammals, most noxious (painful) stimuli as well as innocuous stimuli are detected by spinal afferent neurons, whose cell bodies lie in dorsal root ganglia (DRGs). One of the major unresolved questions is the location, morphology, and neurochemistry of the nerve endings of spinal afferents that actually detect these stimuli in the viscera. In the upper gastrointestinal (GI) tract, there have been many anterograde tracing studies of vagal afferent endings, but none on spinal afferent endings. Recently, we developed a technique that now provides selective labeling of only spinal afferents. We used this approach to identify spinal afferent nerve endings in the upper GI tract of mice. Animals were anesthetized, and injections of dextran-amine were made into thoracic DRGs (T8-T12). Seven days post surgery, mice were euthanized, and the stomach and esophagus were removed, fixed, and stained for calcitonin gene-related peptide (CGRP). Spinal afferent axons were identified that ramified extensively through many rows of myenteric ganglia and formed nerve endings in discrete anatomical layers. Most commonly, intraganglionic varicose endings (IGVEs) were identified in myenteric ganglia of the stomach and varicose simple-type endings in the circular muscle and mucosa. Less commonly, nerve endings were identified in internodal strands, blood vessels, submucosal ganglia, and longitudinal muscle. In the esophagus, only IGVEs were identified in myenteric ganglia. No intraganglionic lamellar endings (IGLEs) were identified in the stomach or esophagus. We present the first identification of spinal afferent endings in the upper GI tract. Eight distinct types of spinal afferent endings were identified in the stomach, and most of them were CGRP immunoreactive. J. Comp. Neurol. 524:3064-3083, 2016. © 2016 Wiley Periodicals, Inc. PMID:27019197

  13. TRPV1 Channels and Gastric Vagal Afferent Signalling in Lean and High Fat Diet Induced Obese Mice

    PubMed Central

    Kentish, Stephen J.; Frisby, Claudine L.; Kritas, Stamatiki; Li, Hui; Hatzinikolas, George; O’Donnell, Tracey A.; Wittert, Gary A.; Page, Amanda J.

    2015-01-01

    Aim Within the gastrointestinal tract vagal afferents play a role in control of food intake and satiety signalling. Activation of mechanosensitive gastric vagal afferents induces satiety. However, gastric vagal afferent responses to mechanical stretch are reduced in high fat diet mice. Transient receptor potential vanilloid 1 channels (TRPV1) are expressed in vagal afferents and knockout of TRPV1 reduces gastro-oesophageal vagal afferent responses to stretch. We aimed to determine the role of TRPV1 on gastric vagal afferent mechanosensitivity and food intake in lean and HFD-induced obese mice. Methods TRPV1+/+ and -/- mice were fed either a standard laboratory diet or high fat diet for 20wks. Gastric emptying of a solid meal and gastric vagal afferent mechanosensitivity was determined. Results Gastric emptying was delayed in high fat diet mice but there was no difference between TRPV1+/+ and -/- mice on either diet. TRPV1 mRNA expression in whole nodose ganglia of TRPV1+/+ mice was similar in both dietary groups. The TRPV1 agonist N-oleoyldopamine potentiated the response of tension receptors in standard laboratory diet but not high fat diet mice. Food intake was greater in the standard laboratory diet TRPV1-/- compared to TRPV1+/+ mice. This was associated with reduced response of tension receptors to stretch in standard laboratory diet TRPV1-/- mice. Tension receptor responses to stretch were decreased in high fat diet compared to standard laboratory diet TRPV1+/+ mice; an effect not observed in TRPV1-/- mice. Disruption of TRPV1 had no effect on the response of mucosal receptors to mucosal stroking in mice on either diet. Conclusion TRPV1 channels selectively modulate gastric vagal afferent tension receptor mechanosensitivity and may mediate the reduction in gastric vagal afferent mechanosensitivity in high fat diet-induced obesity. PMID:26285043

  14. 48. DETAIL VIEW OF AIR VENT AT 'CATFISH' LAUNCH PAD ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    48. DETAIL VIEW OF AIR VENT AT 'CATFISH' LAUNCH PAD Everett Weinreb, photographer, March 1988 - Mount Gleason Nike Missile Site, Angeles National Forest, South of Soledad Canyon, Sylmar, Los Angeles County, CA

  15. 43. DETAIL VIEW OF 'CATFISH' LAUNCH PAD (continues view of ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    43. DETAIL VIEW OF 'CATFISH' LAUNCH PAD (continues view of CA-57-7) Everett Weinreb, photographer, March 1988 - Mount Gleason Nike Missile Site, Angeles National Forest, South of Soledad Canyon, Sylmar, Los Angeles County, CA

  16. 32. DETAIL VIEW OF CAMERA PIT SOUTH OF LAUNCH PAD ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    32. DETAIL VIEW OF CAMERA PIT SOUTH OF LAUNCH PAD WITH CAMERA AIMED AT LAUNCH DECK; VIEW TO NORTHEAST. - Cape Canaveral Air Station, Launch Complex 17, Facility 28402, East end of Lighthouse Road, Cape Canaveral, Brevard County, FL

  17. 21 CFR 872.3540 - OTC denture cushion or pad.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...-counter. (b) Classification. (1) Class I if the device is made of wax-impregnated cotton cloth that the... denture cushion or pad is made of a material other than wax-impregnated cotton cloth or if the...

  18. 21 CFR 872.3540 - OTC denture cushion or pad.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...-counter. (b) Classification. (1) Class I if the device is made of wax-impregnated cotton cloth that the... denture cushion or pad is made of a material other than wax-impregnated cotton cloth or if the...

  19. 21 CFR 872.3540 - OTC denture cushion or pad.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...-counter. (b) Classification. (1) Class I if the device is made of wax-impregnated cotton cloth that the... denture cushion or pad is made of a material other than wax-impregnated cotton cloth or if the...

  20. 21 CFR 872.3540 - OTC denture cushion or pad.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...-counter. (b) Classification. (1) Class I if the device is made of wax-impregnated cotton cloth that the... denture cushion or pad is made of a material other than wax-impregnated cotton cloth or if the...

  1. 21 CFR 872.3540 - OTC denture cushion or pad.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...-counter. (b) Classification. (1) Class I if the device is made of wax-impregnated cotton cloth that the... denture cushion or pad is made of a material other than wax-impregnated cotton cloth or if the...

  2. Preventive medicine oversight of splash pads on military installations.

    PubMed

    Hardcastle, Lisa Raysby; Perry, Matthew; Browne, Ashley

    2015-01-01

    Over the past several years, an increasing number of military installations have installed splash pads that provide fun, recreational water entertainment for Soldiers and their families. The addition of splash pads brings added responsibilities for medical treatment facility preventive medicine oversight and installation facilities maintenance to ensure a safe and healthy environment. Currently, there are no consistent standards or detailed guidance for military installations to follow when installing and maintaining splash pads. The central issues associated with splash pads on military installations are water quality and risk for waterborne illnesses, responsibility for safety and health oversight, and federal energy and water sustainability mandates. This article examines the importance of implementing a standard for design and oversight to ensure the health and safety of Soldiers and their families. PMID:25651143

  3. Overview of the Colorado River Canyon from the helicopter pad. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Overview of the Colorado River Canyon from the helicopter pad. View of the Nevada side where new bridge will cross canyon, view northwest - Hoover Dam, Spanning Colorado River at Route 93, Boulder City, Clark County, NV

  4. Correlations for Saturation Efficiency of Evaporative Cooling Pads

    NASA Astrophysics Data System (ADS)

    Jain, J. K.; Hindoliya, D. A.

    2014-01-01

    This paper presents some experimental investigations to obtain correlations for saturation efficiency of evaporative cooling pads. Two commonly used materials namely aspen and khus fibers along with new materials namely coconut fibers and palash fibers were tested in a laboratory using suitably fabricated test setup. Simple mathematical correlations have been developed for calculating saturation efficiency of evaporating cooling pads which can be used to predict their performance at any desired mass flow rate. Performances of four different pad materials were also compared using developed correlations. An attempt was made to test two new materials (i.e. fibers of palash wood and coconut) to check their suitability as wetted media for evaporative cooling pads. It was found that Palash wood fibers offered highest saturation efficiency compared to that of other existing materials such as aspen and khus fibers at different mass flow rate of air.

  5. 35. Photocopy of Photograph VIEW TO EAST, VIEW OF PAD ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    35. Photocopy of Photograph VIEW TO EAST, VIEW OF PAD B LAUNCH DECK AND UMBILICAL MAST, 28 February 1966. - Cape Canaveral Air Station, Launch Complex 17, Facility 28402, East end of Lighthouse Road, Cape Canaveral, Brevard County, FL

  6. 19. MUELLER FIRE HYDRANT NEAR LAUNCHING PAD IN STATION "0". ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    19. MUELLER FIRE HYDRANT NEAR LAUNCHING PAD IN STATION "0". - Edwards Air Force Base, South Base Sled Track, Edwards Air Force Base, North of Avenue B, between 100th & 140th Streets East, Lancaster, Los Angeles County, CA

  7. 58. Overall view of entry to launch pad from inside ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    58. Overall view of entry to launch pad from inside gate with building 157, sentry control box on right, looking northeast - Nike Missile Battery MS-40, County Road No. 260, Farmington, Dakota County, MN

  8. 56. Overall view towards launch pad with building 157, sentry ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    56. Overall view towards launch pad with building 157, sentry control box on left, and building 156, Warhead Building on right, looking southwest - Nike Missile Battery MS-40, County Road No. 260, Farmington, Dakota County, MN

  9. 16 CFR 1632.5 - Mattress pad test procedure.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. (v) A different number of... substrate. (b) Flame resistant mattress pads. The following additional requirements shall be applicable...

  10. 16 CFR 1632.5 - Mattress pad test procedure.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. (v) A different number of... substrate. (b) Flame resistant mattress pads. The following additional requirements shall be applicable...

  11. 2. CONCRETE PADDING AREA BETWEEN BERM MOUNDS, LOOKING NORTH FROM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. CONCRETE PADDING AREA BETWEEN BERM MOUNDS, LOOKING NORTH FROM TOP OF BERM. - NIKE Missile Base C-84, Acid Fueling Station, North of Launch Area Entrance Drive, eastern central portion of base, Barrington, Cook County, IL

  12. 8. View east. East abutment, showing bearings on concrete pads, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. View east. East abutment, showing bearings on concrete pads, drainage pipes for approach, and scupper downspouts. - Walpole-Westminster Bridge, Spanning Connecticut River between Walpole, NH & Westminster, VT, Walpole, Cheshire County, NH

  13. 7. Shed and keeper' house with helicopter pad in foreground, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. Shed and keeper' house with helicopter pad in foreground, view east, southwest and northwest sides - Goat Island Light Station, Goat Island, next to entrance to Cape Porpoise Harbor, just south of Trott Island, Cape Porpoise, York County, ME

  14. Orbital Rolls to Launch Pad at Wallops for Station Flight

    NASA Video Gallery

    An Orbital Sciences Corporation Antares rolled out to launch Pad-0A at NASA's Wallops Flight Facility, Sunday, January 5, 2014, in advance of a planned Wednesday, Jan. 8th, 1:32 p.m. EST launch. Th...

  15. 16. CONCRETE PAD ON WHICH AN ELECTRICAL REACTOR WAS MOUNTED, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    16. CONCRETE PAD ON WHICH AN ELECTRICAL REACTOR WAS MOUNTED, IN THE BASEMENT, EAST WALL - Bonneville Power Administration South Bank Substation, I-84, South of Bonneville Dam Powerhouse, Bonneville, Multnomah County, OR

  16. Time-Lapse: Mobile Launcher Moves to Launch Pad

    NASA Video Gallery

    The mobile launcher that will host NASA's Space Launch System and new Orion spacecraft was moved to Launch Pad 39B at NASA's Kennedy Space Center in Florida to begin two weeks of structural and sys...

  17. 4. VIEW SOUTHEAST, COMPRESSOR PADS Imperial Carbon Black Plant ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. VIEW SOUTHEAST, COMPRESSOR PADS - Imperial Carbon Black Plant (Ruin), North side of North Fork of Hughes River along Bunnell Run Road just over 0.5 mile from its intersection with State Route 16, Harrisville, Ritchie County, WV

  18. 2. VIEW SOUTHWEST, COMPRESSOR PADS Imperial Carbon Black Plant ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. VIEW SOUTHWEST, COMPRESSOR PADS - Imperial Carbon Black Plant (Ruin), North side of North Fork of Hughes River along Bunnell Run Road just over 0.5 mile from its intersection with State Route 16, Harrisville, Ritchie County, WV

  19. Behind the Scenes: Shuttle Crawls to Launch Pad

    NASA Video Gallery

    In this episode of NASA Behind the Scenes, take a look at what's needed to roll a space shuttle out of the Vehicle Assembly Building and out to the launch pad. Astronaut Mike Massimino talks to som...

  20. Xanthine oxidase, but not neutrophils, contributes to activation of cardiac sympathetic afferents during myocardial ischaemia in cats

    PubMed Central

    Tjen-A-Looi, Stephanie C; Fu, Liang-Wu; Longhurst, John C

    2002-01-01

    Activation of cardiac sympathetic afferents during myocardial ischaemia causes angina and induces important cardiovascular reflex responses. Reactive oxygen species (ROS) are important chemical stimuli of cardiac afferents during and after ischaemia. Iron-catalysed Fenton chemistry constitutes one mechanism of production of hydroxyl radicals. Another potential source of these species is xanthine oxidase-catalysed oxidation of purines. Polymorphonuclear leukocytes (PMNs) also contribute to the production of ROS in some conditions. The present study tested the hypothesis that both xanthine oxidase-catalysed oxidation of purines and neutrophils provide a source of ROS sufficient to activate cardiac afferents during ischaemia. We recorded single-unit activity of cardiac afferents innervating the ventricles recorded from the left thoracic sympathetic chain (T1-5) of anaesthetized cats to identify the afferents' responses to ischaemia. The role of xanthine oxidase in activation of these afferents was determined by infusion of oxypurinol (10 mg kg−1, i.v.), an inhibitor of xanthine oxidase. The importance of neutrophils as a potential source of ROS in the activation of cardiac afferents during ischaemia was assessed by the infusion of a polyclonal antibody (3 mg ml−1 kg−1, i.v.) raised in rabbits immunized with cat PMNs. This antibody decreased the number of circulating PMNs and, to a smaller extent, platelets. Since previous data suggest that platelets release serotonin (5-HT), which activates cardiac afferents through a serotonin receptor (subtype 3,5-HT3 receptor) mechanism, before treatment with the antibody in another group, we blocked 5-HT3 receptors on sensory nerve endings with tropisetron (300 μg kg−1, i.v.). We observed that oxypurinol significantly decreased the activity of cardiac afferents during myocardial ischaemia from 1.5 ± 0.4 to 0.8 ± 0.4 impulses s−1. Similarly, the polyclonal antibody significantly reduced the discharge frequency of

  1. Dynamic changes of depolarizing GABA in a computational model of epileptogenic brain: Insight for Dravet syndrome.

    PubMed

    Kurbatova, P; Wendling, F; Kaminska, A; Rosati, A; Nabbout, R; Guerrini, R; Dulac, O; Pons, G; Cornu, C; Nony, P; Chiron, C; Benquet, P

    2016-09-01

    Abnormal reemergence of depolarizing GABAA current during postnatal brain maturation may play a major role in paediatric epilepsies, Dravet syndrome (DS) being among the most severe. To study the impact of depolarizing GABA onto distinct patterns of EEG activity, we extended a neural mass model as follows: one sub-population of pyramidal cells was added as well as two sub-populations of interacting interneurons, perisomatic-projecting interneurons (basket-like) with fast synaptic kinetics GABAA (fast, I1) and dendritic-projecting interneurons with slow synaptic kinetics GABAA (slow, I2). Basket-like cells were interconnected to reproduce mutual inhibition mechanisms (I1➔I1). The firing rate of interneurons was adapted to mimic the genetic alteration of voltage gated sodium channels found in DS patients, SCN1A(+/-). We implemented the "dynamic depolarizing GABAA" mediated post-synaptic potential in the model, as some studies reported that the chloride reversal potential can switch from negative to more positive value depending on interneuron activity. The "shunting inhibition" promoted by GABAA receptor activation was also implemented. We found that increasing the proportion of depolarizing GABAA mediated IPSP (I1➔I1 and I1➔P) only (i.e., other parameters left unchanged) was sufficient to sequentially switch the EEG activity from background to (1) interictal isolated polymorphic epileptic spikes, (2) fast onset activity, (3) seizure like activity and (4) seizure termination. The interictal and ictal EEG patterns observed in 4 DS patients were reproduced by the model via tuning the amount of depolarizing GABAA postsynaptic potential. Finally, we implemented the modes of action of benzodiazepines and stiripentol, two drugs recommended in DS. Both drugs blocked seizure-like activity, partially and dose-dependently when applied separately, completely and with a synergic effect when combined, as has been observed in DS patients. This computational modeling study

  2. Research in depolarization of particles in Tibetan Plateau and coastal area by lidar

    NASA Astrophysics Data System (ADS)

    Dai, Guangyao; Wu, Songhua; Song, Xiaoquan; Qin, Shengguang; Liu, Bingyi; Liu, Jintao; Zhang, Kailin; Zhang, Wei

    2014-11-01

    Vertical profiles of the linear particle depolarization ratio p δ of cloud and aerosol in the Tibet Plateau were measured during the Tibetan Plateau atmospheric expedition experiment campaign with water vapor, cloud and aerosol lidar system, which is capable of depolarization ratio measurement. The atmospheric comprehensive observations were performed during July of 2013 at Litang (30.03°N,100.28°E), which is 3949 meters above the mean sea level, Sichuan province, China. It was the first time to detect and obtain the Tibetan Plateau cloud and aerosol lidar depolarization profiles to our knowledge. After completing the plateau experiment campaign, the lidar system measured the atmosphere above coastal area in Qingdao (36.165°N,120.4956°E). In this year, we continued to participate in the plateau experiment campaign in Nagchu (31.5°N,92.05°E), which is 4600 meters above the mean sea level, The Tibet Autonomous Region from 1st, July to 1st, September. Since particle size, shape and refractive index have an impact on linear particle depolarization ratio, one can classify the aerosol types and cloud phase in turn in the Tibetan Plateau and Qingdao area using linear particle depolarization ratio data. Generally, two calibration methods were applied: comparison of the lidar measurement data and CALIPSO simultaneous data method and half-wave plate ±45°switch method. In this paper we applied the comparison calibration method. The correlation coefficient between lidar measurement data and CALIPSO data reaches up to 84.92%, which shows great linear relation. Finally, after the calculation and calibration of the linear particle depolarization ratio measured during the plateau experiment campaign and observation in coastal area, the ice-water mixed cloud (0.15< p δ <0.5), water cloud ( p δ <0.15) and dusty mix(0.2< p δ <0.35) in Tibetan Plateau were occurred and classified. Meanwhile, the cirrus clouds ( p δ <0.5), water cloud, smoke and urban pollution (0.05< p

  3. Method for Producing Launch/Landing Pads and Structures Project

    NASA Technical Reports Server (NTRS)

    Mueller, Robert P. (Compiler)

    2015-01-01

    Current plans for deep space exploration include building landing-launch pads capable of withstanding the rocket blast of much larger spacecraft that that of the Apollo days. The proposed concept will develop lightweight launch and landing pad materials from in-situ materials, utilizing regolith to produce controllable porous cast metallic foam brickstiles shapes. These shapes can be utilized to lay a landing launch platform, as a construction material or as more complex parts of mechanical assemblies.

  4. Assessment of Raman Spectroscopy as a Silicone Pad Production Diagnostic

    SciTech Connect

    Saab, A P; Balazs, G B; Maxwell, R S

    2005-05-05

    Silicone pressure pads are currently deployed in the W80. The mechanical properties of these pads are largely based on the degree of crosslinking between the polymer components that comprise the raw gumstock from which they are formed. Therefore, it is desirable for purposes of both production and systematic study of these materials to have a rapid, reliable means of assaying the extent of crosslinking. The present report describes the evaluation of Raman spectroscopy in this capacity.

  5. 44. VIEW OF UMBILICAL MAST AND LAUNCH PAD FROM SOUTHWEST. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    44. VIEW OF UMBILICAL MAST AND LAUNCH PAD FROM SOUTHWEST. DOORS FOR THE UMBILICAL MAST TRENCH RAISED FOR MAINTENANCE POSITION OF 10 DEGREES. LAUNCHER IS RIGHT OF MAST; RAILS PARALLEL TO MAST. CONTROL PANELS LEFT TO RIGHT: ELECTRICAL PANEL, COMMUNICATIONS PANEL, AND MAST CONTROL PANEL. - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 East, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

  6. Demonstrating Optical Activity Using an iPad

    ERIC Educational Resources Information Center

    Schwartz, Pauline M.; Lepore, Dante M.; Morneau, Brandy N.; Barratt, Carl

    2011-01-01

    Optical activity using an iPad as a source of polarized light is demonstrated. A sample crystal or solution can be placed on the iPad running a white screen app. The sample is viewed through a polarized filter that can be rotated. This setup can be used in the laboratory or with a document camera to easily project in a large lecture hall.…

  7. Riverland ERA maintenance pad site diesel contamination risk assessment

    SciTech Connect

    Valcich, P.J.

    1993-12-02

    The maintenance pad site consists of a concrete pad and underlying soils, approximately 15 by 46 m in area, and a drainage ditch with dimensions of 2.4 by 91 m. The ditch is located approximately 60 m from the concrete pad and is oriented parallel to the pads long axis. The facility was built in 1943, at which time the concrete pad was the floor of a maintenance shed for railroad activities. In 1955, use of the facility as a maintenance shed was discontinued. Between 1955 and 1957, the facility was used as a radioactivity decontamination area for railroad cars; acetone-soaked rags were used to remove surface contamination from the cars. The concrete pad was washed down with a mixture of water and diesel fuel, which was then flushed via clay pipe to the drainage ditch. In 1963, the maintenance shed was torn down and the concrete pad covered with approximately one-half meter of fill. The concrete pad was re-exposed in 1993. The site was sampled for Toxicity Characteristic Leachate Procedure (TCLP) metals, volatile, and semi-volatile compounds, as well as for extractable fuel hydrocarbons. A total of 17 samples were collected from surface concrete, soil beneath surface concrete, and ditch soil. One concrete sample and one ditch soil sample were split. The ditch soil sample was also duplicated. The relative percent difference (RPD) in extractable hydrocarbons of the two split samples, one from concrete and one from ditch soil are, respectively, 52% and 186%. The RPD for the duplicate sample, taken from the same ditch soil sample from which one of the splits was taken, is 39%.

  8. GluA2-Containing AMPA Receptors Distinguish Ribbon-Associated from Ribbonless Afferent Contacts on Rat Cochlear Hair Cells123

    PubMed Central

    Martinez-Monedero, Rodrigo

    2016-01-01

    Abstract Mechanosensory hair cells release glutamate at ribbon synapses to excite postsynaptic afferent neurons, via AMPA-type ionotropic glutamate receptors (AMPARs). However, type II afferent neurons contacting outer hair cells in the mammalian cochlea were thought to differ in this respect, failing to show GluA immunolabeling and with many “ribbonless” afferent contacts. Here it is shown that antibodies to the AMPAR subunit GluA2 labeled afferent contacts below inner and outer hair cells in the rat cochlea, and that synaptic currents in type II afferents had AMPAR-specific pharmacology. Only half the postsynaptic densities of type II afferents that labeled for PSD-95, Shank, or Homer were associated with GluA2 immunopuncta or presynaptic ribbons, the “empty slots” corresponding to ribbonless contacts described previously. These results extend the universality of AMPAergic transmission by hair cells, and support the existence of silent afferent contacts. PMID:27257620

  9. Opioids inhibit visceral afferent activation of catecholamine neurons in the solitary tract nucleus.

    PubMed

    Cui, R J; Roberts, B L; Zhao, H; Andresen, M C; Appleyard, S M

    2012-10-11

    Brainstem A2/C2 catecholamine (CA) neurons within the solitary tract nucleus (NTS) influence many homeostatic functions, including food intake, stress, respiratory and cardiovascular reflexes. They also play a role in both opioid reward and withdrawal. Injections of opioids into the NTS modulate many autonomic functions influenced by catecholamine neurons including food intake and cardiac function. We recently showed that NTS-CA neurons are directly activated by incoming visceral afferent inputs. Here we determined whether opioid agonists modulate afferent activation of NTS-CA neurons using transgenic mice with EGFP expressed under the control of the tyrosine hydroxylase promoter (TH-EGFP) to identify catecholamine neurons. The opioid agonist Met-enkephalin (Met-Enk) significantly attenuated solitary tract-evoked excitatory postsynaptic currents (ST-EPSCs) in NTS TH-EGFP neurons by 80%, an effect reversed by wash or the mu opioid receptor-specific antagonist D-Phe-Cys-Tyr-D-Trp-Orn-Thr-Pen-Thr-NH(2) (CTOP). Met-Enk had a significantly greater effect to inhibit afferent inputs onto TH-EGFP-positive neurons than EGFP-negative neurons, which were only inhibited by 50%. The mu agonist, DAMGO, also inhibited the ST-EPSC in TH-EGFP neurons in a dose-dependent manner. In contrast, neither the delta agonist DPDPE, nor the kappa agonist, U69,593, consistently inhibited the ST-EPSC amplitude. Met-Enk and DAMGO increased the paired pulse ratio, decreased the frequency, but not amplitude, of mini-EPSCs and had no effect on holding current, input resistance or current-voltage relationships in TH-EGFP neurons, suggesting a presynaptic mechanism of action on afferent terminals. Met-Enk significantly reduced both the basal firing rate of NTS TH-EGFP neurons and the ability of afferent stimulation to evoke an action potential. These results suggest that opioids inhibit NTS-CA neurons by reducing an excitatory afferent drive onto these neurons through presynaptic inhibition of

  10. In pursuit of P2X3 antagonists: novel therapeutics for chronic pain and afferent sensitization.

    PubMed

    Ford, Anthony P

    2012-02-01

    Treating pain by inhibiting ATP activation of P2X3-containing receptors heralds an exciting new approach to pain management, and Afferent's program marks the vanguard in a new class of drugs poised to explore this approach to meet the significant unmet needs in pain management. P2X3 receptor subunits are expressed predominately and selectively in so-called C- and Aδ-fiber primary afferent neurons in most tissues and organ systems, including skin, joints, and hollow organs, suggesting a high degree of specificity to the pain sensing system in the human body. P2X3 antagonists block the activation of these fibers by ATP and stand to offer an alternative approach to the management of pain and discomfort. In addition, P2X3 is expressed pre-synaptically at central terminals of C-fiber afferent neurons, where ATP further sensitizes transmission of painful signals. As a result of the selectivity of the expression of P2X3, there is a lower likelihood of adverse effects in the brain, gastrointestinal, or cardiovascular tissues, effects which remain limiting factors for many existing pain therapeutics. In the periphery, ATP (the factor that triggers P2X3 receptor activation) can be released from various cells as a result of tissue inflammation, injury or stress, as well as visceral organ distension, and stimulate these local nociceptors. The P2X3 receptor rationale has aroused a formidable level of investigation producing many reports that clarify the potential role of ATP as a pain mediator, in chronic sensitized states in particular, and has piqued the interest of pharmaceutical companies. P2X receptor-mediated afferent activation has been implicated in inflammatory, visceral, and neuropathic pain states, as well as in airways hyperreactivity, migraine, itch, and cancer pain. It is well appreciated that oftentimes new mechanisms translate poorly from models into clinical efficacy and effectiveness; however, the breadth of activity seen from P2X3 inhibition in models offers

  11. Firing of antagonist small-diameter muscle afferents reduces voluntary activation and torque of elbow flexors.

    PubMed

    Kennedy, David S; McNeil, Chris J; Gandevia, Simon C; Taylor, Janet L

    2013-07-15

    During muscle fatigue, firing of small-diameter muscle afferents can decrease voluntary activation of the fatigued muscle. However, these afferents may have a more widespread effect on other muscles in the exercising limb. We examined if the firing of fatigue-sensitive afferents from elbow extensor muscles in the same arm reduces torque production and voluntary activation of elbow flexors. In nine subjects we examined voluntary activation of elbow flexors by measuring changes in superimposed twitches evoked by transcranial magnetic stimulation of the motor cortex during brief (2-3 s) maximal voluntary contractions (MVC). Inflation of a blood pressure cuff following a 2-min sustained MVC blocked blood flow to the fatigued muscle and maintained firing of small-diameter afferents. After a fatiguing elbow flexion contraction, maximal flexion torque was lower (26.0 ± 4.4% versus 67.9 ± 5.2% of initial maximal torque; means ± s.d.; P < 0.001) and superimposed twitches were larger (4.1 ± 1.1% versus 1.8 ± 0.2% ongoing MVC, P = 0.01) with than without ischaemia. After a fatiguing elbow extensor contraction, maximal flexion torque was also reduced (82.2 ± 4.9% versus 91.4 ± 2.3% of initial maximal torque; P = 0.007), superimposed twitches were larger (2.7 ± 0.7% versus 1.3 ± 0.2% ongoing MVC; P = 0.02) and voluntary activation lower (81.6 ± 8.2% versus 95.5 ± 6.9%; P = 0.04) with than without ischaemia. After a fatiguing contraction, voluntary drive to the fatigued muscles is reduced with continued input from small-diameter muscle afferents. Furthermore, fatigue of the elbow extensor muscles decreases voluntary drive to unfatigued elbow flexors of the same arm. Therefore, firing of small-diameter muscle afferents from one muscle can affect voluntary activation and hence torque generation of another muscle in the same limb. PMID:23652589

  12. 21 CFR 884.5425 - Scented or scented deodorized menstrual pad.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Scented or scented deodorized menstrual pad. 884... Therapeutic Devices § 884.5425 Scented or scented deodorized menstrual pad. (a) Identification. A scented or scented deodorized menstrual pad is a device that is a pad made of cellulosic or synthetic material...

  13. The CIMSS iPad Library and ESIP Teacher Workshops

    NASA Astrophysics Data System (ADS)

    Dahlman, L.; Mooney, M. E.

    2012-12-01

    The Cooperative Institute for Meteorological Satellite Studies (CIMSS) at the University of Wisconsin-Madison launched a new initiative in 2012 to engage teachers and students in data acquisition and regional climate studies. The CIMSS iPad Library, part of a NASA funded Climate Literacy Ambassadors project, loans iPads to science teachers for an entire school year. The first units were distributed at a NOAA funded teacher workshop conducted at the annual Earth Science Information Partners (ESIP) summer conference. Educators learned about numerous NOAA and NASA resources at the ESIP Teacher Workshop and also several different climate-related Apps, including SatCam, an application for iOS devices that allows users to collect observations of local cloud and surface conditions coordinated with an overpass of the Terra, Aqua, or Suomi NPP satellite. This presentation will outline connections between the Climate Literacy Ambassadors community and ESIP Teacher Workshops before delving into details about the new iPad Library and SatCam. We will discuss considerations and challenges related to a technology loaning library, software recoding to HTML5, and some advantages and limitations related to iPads. We will also share feedback acquired over the fall from ESIP Educators using the SatCam App with their students with the iPads they borrowed (like books) from the CIMSS iPad Library.

  14. Saturn I (SA-1) on Launch Pad

    NASA Technical Reports Server (NTRS)

    1961-01-01

    On October 27, 1961, the Marshall Space Flight Center and the Nation marked a high point in the 3-year-old Saturn development program when the first Saturn vehicle, SA-1, flew a flawless 215-mile ballistic trajectory from Cape Canaveral, Florida. SA-1 is pictured here on the launch pad ready for lift off. Developed at the Marshall Space Flight Center (MSFC) under the direction of Dr. Wernher von Braun, SA-1 incorporated a Saturn I, Block I engine. The typical height of a Block I vehicle was approximately 163 feet and had only one live stage. It consisted of eight tanks, each 70 inches in diameter, clustered around a central tank, 105 inches in diameter. Four of the external tanks were fuel tanks for the RP-1 (kerosene) fuel. The other four, spaced alternately with the fuel tanks, were liquid oxygen tanks, as was the large center tank. All fuel tanks and liquid oxygen tanks drained at the same rates respectively. The thrust for the stage came from eight H-1 engines, each producing a thrust of 165,000 pounds, for a total thrust of over 1,300,000 pounds. The engines were arranged in a double pattern. Four engines, located inboard, were fixed in a square pattern around the stage axis and canted outward slightly, while the remaining four engines were located outboard in a larger square pattern offset 40 degrees from the inner pattern. Unlike the inner engines, each outer engine was gimbaled. That is, each could be swung through an arc. They were gimbaled as a means of steering the rocket, by letting the instrumentation of the rocket correct any deviations of its powered trajectory. The block I required engine gimabling as the only method of guiding and stabilizing the rocket through the lower atmosphere. The upper stages of the Block I rocket reflected the three-stage configuration of the Saturn I vehicle.

  15. Aircraft Conceptual Design Using Vehicle Sketch Pad

    NASA Technical Reports Server (NTRS)

    Fredericks, William J.; Antcliff, Kevin R.; Costa, Guillermo; Deshpande, Nachiket; Moore, Mark D.; Miguel, Edric A. San; Snyder, Alison N.

    2010-01-01

    Vehicle Sketch Pad (VSP) is a parametric geometry modeling tool that is intended for use in the conceptual design of aircraft. The intent of this software is to rapidly model aircraft configurations without expending the expertise and time that is typically required for modeling with traditional Computer Aided Design (CAD) packages. VSP accomplishes this by using parametrically defined components, such as a wing that is defined by span, area, sweep, taper ratio, thickness to cord, and so on. During this phase of frequent design builds, changes to the model can be rapidly visualized along with the internal volumetric layout. Using this geometry-based approach, parameters such as wetted areas and cord lengths can be easily extracted for rapid external performance analyses, such as a parasite drag buildup. At the completion of the conceptual design phase, VSP can export its geometry to higher fidelity tools. This geometry tool was developed by NASA and is freely available to U.S. companies and universities. It has become integral to conceptual design in the Aeronautics Systems Analysis Branch (ASAB) here at NASA Langley Research Center and is currently being used at over 100 universities, aerospace companies, and other government agencies. This paper focuses on the use of VSP in recent NASA conceptual design studies to facilitate geometry-centered design methodology. Such a process is shown to promote greater levels of creativity, more rapid assessment of critical design issues, and improved ability to quickly interact with higher order analyses. A number of VSP vehicle model examples are compared to CAD-based conceptual design, from a designer perspective; comparisons are also made of the time and expertise required to build the geometry representations as well.

  16. Practical depolarization-ratio-based inversion procedure: lidar measurements of the Eyjafjallajökull ash cloud over the Netherlands.

    PubMed

    Donovan, David Patrick; Apituley, Arnoud

    2013-04-10

    In this paper we present a technique for estimating optical backscatter and extinction profiles using lidar, which exploits the difference between the observed linear volume depolarization ratio at 355 nm and the corresponding expected aerosol-only depolarization ratio. The technique is specific to situations where a single strongly depolarizing species is present and the associated linear particulate depolarization ratio may be presumed to be known to within a reasonable degree of accuracy (on the order of 10%). The basic principle of the technique is extended to deal with situations where a depolarizing fraction is mixed with nondepolarizing aerosol. In general, since the relative depolarization interchannel calibration is much more stable than the absolute system calibration, the depolarization-based technique is easier to implement than conventional techniques that require a profile-by-profile calibration or, equivalently, an identification of aerosol-free altitude intervals. This in particular allows for unattended data analysis and makes the technique well-suited to be part of a broader (volcanic ash) surveillance system. The technique is demonstrated by applying it to the analysis of aerosol layers resulting from the 2010 eruptions of the Eyjafjallajökull volcano in Iceland. The measurements were made at the Cabauw remote-sensing site in the central Netherlands. By comparing the results of the depolarization-based inversion with a more conventional manual inversion procedure as well as Raman lidar results, it is demonstrated that the technique can be successfully applied to the particular case of 355 nm depolarization lidar volcanic ash soundings, including cases in which the ash is mixed with nondepolarizing aerosol. PMID:23670771

  17. Depolarization-induced contractile activity of smooth muscle in calcium-free solution.

    PubMed

    Mangel, A W; Nelson, D O; Rabovsky, J L; Prosser, C L; Connor, J A

    1982-01-01

    In calcium-free solution, strips of cat intestinal muscle developed slow, rhythmic electrical potential changes that triggered contractions. Some strips failed to develop spontaneous electrical activity in calcium-free solution but responded with contractions to depolarization by direct electrical stimulation or by treatment with barium chloride, potassium chloride, or acetylcholine. Similar results were obtained with segments of cat stomach, colon, esophagus, bladder, uterus, and vena cava, as well as with rabbit vena cava. In calcium-free saline, rat small intestinal muscle showed fast electrical activity with accompanying development of a tetanuslike contraction. After 60 min in calcium-free solution, cat small intestinal muscle retained 17.7% of its original concentration of calcium. It is concluded that in some smooth muscles, depolarization-triggered release of intracellular calcium does not require an associated influx of calcium. PMID:7058877

  18. Separable phases of light-evoked depolarizations in the retina of Strombus.

    PubMed

    Quandt, F N; Gillary, H L

    1980-02-01

    The waveforms of light-evoked depolarizations in Strombus retinal neurones can exhibit two sequential peaks or phases, the relative amplitudes of which vary with changes in stimulus intensity and interstimulus interval. Experiments employing either the passage of constant intracellular current or voltage clamp techniques indicate that both phases reverse polarity at intracellular potentials less negative than the resting potential. The potential at which the first phase reverses its polarity is considerably more positive than that of the second phase. The results indicate that the light-evoked depolarizations are generated by at least two different processes; these appear to be separate conductance changes, neither of which is voltage dependent. Under certain conditions, the second phase was inhibited by high extracellular concentrations of Mg2+, indicating that it may arise as a result of chemically mediated synaptic transmission. The first phase did not show such inhibition and appears to be caused by the direct action of light on the cell. PMID:7365412

  19. Failure of feedback as a putative common mechanism of spreading depolarizations in migraine and stroke

    NASA Astrophysics Data System (ADS)

    Dahlem, Markus A.; Schneider, Felix M.; Schöll, Eckehard

    2008-06-01

    The stability of cortical function depends critically on proper regulation. Under conditions of migraine and stroke a breakdown of transmembrane chemical gradients can spread through cortical tissue. A concomitant component of this emergent spatio-temporal pattern is a depolarization of cells detected as slow voltage variations. The propagation velocity of ˜3mm/min indicates a contribution of diffusion. We propose a mechanism for spreading depolarizations (SD) that rests upon a nonlocal or noninstantaneous feedback in a reaction-diffusion system. Depending upon the characteristic space and time scales of the feedback, the propagation of cortical SD can be suppressed by shifting the bifurcation line, which separates the parameter regime of pulse propagation from the regime where a local disturbance dies out. The optimization of this feedback is elaborated for different control schemes and ranges of control parameters.

  20. Structure of polarimetric purity of a Mueller matrix and sources of depolarization

    NASA Astrophysics Data System (ADS)

    Gil, José J.

    2016-06-01

    The depolarization properties of a medium with associated Mueller matrix M are characterized through two complementary sets of parameters, namely 1) the three indices of polarimetric purity (IPP), which are directly linked to the relative weights of the spectral components of M and provide complete information on the structure of polarimetric randomness, but are insensitive to the specific polarimetric behaviors that introduce the lack of randomness, and 2) the set of three components of purity (CP), constituted by the polarizance, the diattenuation and the degree of spherical purity. The relations between these sets of physical invariant quantities are studied by means of their representation into a common purity figure. Furthermore, the polarimetric properties of a general Mueller matrix M are parameterized in terms of sixteen meaningful quantities, three of them being the IPP, which together with the CP provide complete information on the integral depolarization properties of the medium.

  1. Backscatter laser depolarization studies of simulated stratospheric aerosols - Crystallized sulfuric acid droplets

    NASA Technical Reports Server (NTRS)

    Sassen, Kenneth; Zhao, Hongjie; Yu, Bing-Kun

    1989-01-01

    The optical depolarizing properties of simulated stratospheric aerosols were studied in laboratory laser (0.633 micrometer) backscattering experiments for application to polarization lidar observations. Clouds composed of sulfuric acid solution droplets, some treated with ammonia gas, were observed during evaporation. The results indicate that the formation of minute ammonium sulfate particles from the evaporation of acid droplets produces linear depolarization ratios of beta equivalent to 0.02, but beta equivalent to 0.10 to 0.15 are generated from aged acid cloud aerosols and acid droplet crystalization effects following the introduction of ammonia gas into the chamber. It is concluded that partially crystallized sulfuric acid droplets are a likely candidate for explaining the lidar beta equivalent to 0.10 values that have been observed in the lower stratosphere in the absence of the relatively strong backscattering from homogeneous sulfuric acid droplet (beta equivalent to 0) or ice crystal (beta equivalent to 0.5) clouds.

  2. Backscatter laser depolarization studies of simulated stratospheric aerosols: Crystallized sulfuric acid droplets

    NASA Technical Reports Server (NTRS)

    Sassen, Kenneth; Zhao, Hongjie; Yu, Bing-Kun

    1988-01-01

    The optical depolarizing properties of simulated stratospheric aerosols were studied in laboratory laser (0.633 micrometer) backscattering experiments for application to polarization lidar observations. Clouds composed of sulfuric acid solution droplets, some treated with ammonia gas, were observed during evaporation. The results indicate that the formation of minute ammonium sulfate particles from the evaporation of acid droplets produces linear depolarization ratios of beta equivalent to 0.02, but beta equivalent to 0.10 to 0.15 are generated from aged acid cloud aerosols and acid droplet crystallization effects following the introduction of ammonia gas into the chamber. It is concluded that partially crystallized sulfuric acid droplets are a likely candidate for explaining the lidar beta equivalent to 0.10 values that have been observed in the lower stratosphere in the absence of the relatively strong backscattering from homogeneous sulfuric acid droplet (beta equivalent to 0) or ice crystal (beta equivalent to 0.5) clouds.

  3. Measurement of the depolarization ratio of Rayleigh scattering at absorption bands

    NASA Astrophysics Data System (ADS)

    Anglister, J.; Steinberg, I. Z.

    1981-01-01

    Measurements of the depolarization ratio ρv of light scattered by the pigments lycopene and β-carotene at the red part of their absorption bands yielded values which are very close to the theoretical value 1/3 of a fully anisotropic molecular polarizability, i.e., that due to an electric dipole moment. Measurements of ρv at the blue edge of the visible absorption band of pinacyanol chloride yielded a value of 0.75 at 472.2 nm, which is the maximum value that a depolarization ratio can assume, and is attained if the average molecular polarizability is zero. This is possible only if the diagonalized polarizability tensor has at least one negative element to counterbalance the positive ones. A negative refractive index at the blue edge of the absorption band is thus experimentally demonstrated.

  4. Research in Depolarization and Extinction Coefficient of Particles in Tibetan Plateau by Lidar

    NASA Astrophysics Data System (ADS)

    Dai, Guangyao; Song, Xiaoquan; Zhai, Xiaochun; Wu, Songhua

    2016-06-01

    Vertical profiles of the depolarization ratio and the extinction coefficient of atmospheric particles in Tibetan Plateau were measured with the OUC Water Vapor, Cloud and Aerosol Lidar during the 3rd Tibetan Plateau Atmospheric Expedition Experiment Campaign in 2013 and 2014. The cloud types and phases, the spatial temporal distribution of the aerosols and the boundary layer height in the Tibetan Plateau were obtained using polarization lidar technique. In this paper, the depolarization ratio was validated with CALIOP polarization simultaneous data, and the extinction coefficient was retrieved by the Fernald method. The result implied that the atmosphere in the Tibetan Plateau was quite clean with low aerosol load and serious pollution. The ice-water mixed cumulus, water cumulus or stratus clouds in Litang and Nagqu were occurred and classified, respectively. The boundary layer height in Nagqu at average altitude over 4600 m was obtained at around 200 m-300 m, which was commonly lower than that in other observed sites.

  5. Depolarization of D-T plasmas by recycling in material walls

    SciTech Connect

    Greenside, H.S.; Budny, R.V.; Post, D.E.

    1984-02-01

    The feasibility of using polarized deuterium (D) and tritium (T) plasmas in fusion reactors may be seriously affected by recycling in material walls. Theoretical and experimental results are reviewed which show how the depolarization rates of absorbed D and T depend on first wall parameters such as the temperature, the bulk and surface diffusivities, the density of electronic states at the Fermi surface, the spectral density of microscopic fluctuating electric field gradients, and the concentration of paramagnetic impurities. Nuclear magnetic resonance (NMR) spectroscopy of hydrogenated and deuterated amorphous semiconductors suggests that low-Z nonmetallic materials may provide a satisfactory first wall or limiter coating under reactor conditions with characteristic depolarization times of several seconds. Experiments are proposed to test the consequences of our analysis.

  6. Extracting the depolarization coefficient DNN from data measured with a full acceptance detector

    NASA Astrophysics Data System (ADS)

    Hauenstein, F.; Clement, H.; Dzhygadlo, R.; Eyrich, W.; Gillitzer, A.; Grzonka, D.; Jowzaee, S.; Ritman, J.; Roderburg, E.; Röder, M.; Wintz, P.

    2016-05-01

    The spin transfer from vertically polarized beam protons to Λ or Σ hyperons of the associated strangeness production p → p →pK+ Λ and p → p →pK0Σ+ is described with the depolarization coefficient DNN. As the polarization of the hyperons is determined by their weak decays, detectors, which have a large acceptance for the decay particles, are needed. In this paper a formula is derived, which describes the depolarization coefficient DNN by count rates of a 4π detector. It is shown that formulas, which are given in publications for detectors with restricted acceptance, are specific cases of this formula for a 4π detector.

  7. Generation of vector beams using a double-wedge depolarizer: Non-quantum entanglement

    NASA Astrophysics Data System (ADS)

    Samlan, C. T.; Viswanathan, Nirmal K.

    2016-07-01

    Propagation of horizontally polarized Gaussian beam through a double-wedge depolarizer generates vector beams with spatially varying state of polarization. Jones calculus is used to show that such beams are maximally nonseparable on the basis of even (Gaussian)-odd (Hermite-Gaussian) mode parity and horizontal-vertical polarization state. The maximum nonseparability in the two degrees of freedom of the vector beam at the double wedge depolarizer output is verified experimentally using a modified Sagnac interferometer and linear analyser projected interferograms to measure the concurrence 0.94±0.002 and violation of Clauser-Horne-Shimony-Holt form of Bell-like inequality 2.704±0.024. The investigation is carried out in the context of the use of vector beams for metrological applications.

  8. Far wing depolarization of light - Generalized absorption profiles. [in laser fluorescence spectroscopy of Sr vapor

    NASA Technical Reports Server (NTRS)

    Thomann, P.; Burnett, K.; Cooper, J.

    1981-01-01

    An absorption (and/or emission) event which takes place during a strong collision is called a 'correlated event'. It is discussed how correlated events affect the far red wing depolarization of fluorescence. Attention is given to an atomic vapor which is irradiated by linearly polarized light of a frequency on the red side of the resonance line. Two limiting cases are considered, corresponding to excitation in the impact region and in the quasi-static wing. In the quasi-static wing, absorption of a photon followed by fluorescence (rather than Rayleigh scattering), occurs mostly during a collision. Correlated events dominate the scattering process. Expressions derived for the polarization of the fluorescent light are applied to far red wing depolarization. It is found that the polarization of the fluorescent light does not go to zero in the far wing, but depends crucially on the detailed nature of the anisotropy in the long-range part of the interatomic potential.

  9. Arctic polar stratospheric cloud measurements by means of a four wavelength depolarization lidar

    NASA Technical Reports Server (NTRS)

    Stefanutti, L.; Castagnoli, F.; Delguasta, M.; Flesia, C.; Godin, S.; Kolenda, J.; Kneipp, H.; Kyro, Esko; Matthey, R.; Morandi, M.

    1994-01-01

    A four wavelength depolarization backscattering lidar has been operated during the European Arctic Stratospheric Ozone Experiment (EASOE) in Sodankyl, in the Finnish Arctic. The lidar performed measurements during the months of December 1991, January, February and March 1992. The Finnish Meteorological Institute during the same period launched regularly three Radiosondes per day, and three Ozone sondes per week. Both Mt. Pinatubo aerosols and Polar Stratospheric Clouds were measured. The use of four wavelengths, respectively at 355 nm, 532 nm , 750 nm, and 850 nm permits an inversion of the lidar data to determine aerosol particle size. The depolarization technique permits the identification of Polar Stratospheric Clouds. Frequent correlation between Ozone minima and peaks in the Mt. Pinatubo aerosol maxima were detected. Measurements were carried out both within and outside the Polar Vortex.

  10. Diffusive transfer of polarized 3He gas through depolarizing magnetic gradients

    NASA Astrophysics Data System (ADS)

    Maxwell, J. D.; Epstein, C. S.; Milner, R. G.

    2015-03-01

    Transfer of polarized 3He gas across spatially varying magnetic fields will facilitate a new source of polarized 3He ions for particle accelerators. In this context, depolarization of atoms as they pass through regions of significant transverse field gradients is a major concern. To understand these depolarization effects, we have built a system consisting of a Helmholtz coil pair and a solenoid, both with central magnetic fields of order 30 gauss. The atoms are polarized via metastability exchange optical pumping in the Helmholtz coil and are in diffusive contact via a glass tube with a second test cell in the solenoid. We have carried out measurements of the spin relaxation during transfer of polarization in 3He at 1 torr by diffusion. We explore the use of measurements of the loss of polarization taken in one cell to infer the polarization in the other cell.

  11. A TRP conductance modulates repolarization after sensory-dependent depolarization in Chlamydomonas reinhardtii

    PubMed Central

    Arias-Darraz, Luis; Colenso, Charlotte K; Veliz, Luis A; Vivar, Juan P; Cardenas, Sylvana; Brauchi, Sebastian

    2015-01-01

    Sensory integration is vital for motile organisms constantly exposed to changing surroundings. Chlamydomonas reinhardtii is a single-celled green alga found swimming in freshwater. In this type of alga, sensory input is first detected by membrane receptors located in the cell body, and then transduced to the beating cilia by membrane depolarization. Many components of the machinery associated with sensory integration in C. reinhardtii, such as chemoreceptors and repolarization-associated channels, are yet uncharacterized. TRP channels are known mediators for cellular sensing in animal cells and it has been suggested that the C. reinhardtii genome encodes for a set of TRP proteins. Here, by combining behavioral studies with electrophysiological experiments conducted on both population and single alga, we test whether TRP channel blockers affect algal swimming behavior. Our results suggest that a TRP conductance is associated to the repolarization that follows a depolarizing receptor potential, highlighting a primitive function of TRP proteins. PMID:26186626

  12. Toward optimizing the detection of atrial depolarization with floating bipolar electrodes.

    PubMed

    Brownlee, R R

    1989-03-01

    Some concepts derived from modern literature on the physics of cardiac muscle conduction regarding optimization of the design of electrode systems for detection of atrial depolarization and a preliminary clinical corroboration of the concepts are presented. The concepts of most import are 1) that the mechanical dimensions of sensing electrodes in all planes have to be as small as possible relative to the dimensions of the extracellular waveform dimensions associated with depolarization action potentials, and 2) that the distance between bipolar electrodes should be tuned to be greater than the dimensions of the extracellular waveform to avoid subtractive interference patterns associated with saltatory propagation in aging cardiac muscle. Additionally, in the practical application of chronic atrial sensing from a single lead for use in an implanted VDD pacing system, it is also important to consider electrode size and its effect on impedance level. PMID:2466269

  13. Surface potential at a ferroelectric grain due to asymmetric screening of depolarization fields

    SciTech Connect

    Genenko, Yuri A. Hirsch, Ofer; Erhart, Paul

    2014-03-14

    Nonlinear screening of electric depolarization fields, generated by a stripe domain structure in a ferroelectric grain of a polycrystalline material, is studied within a semiconductor model of ferroelectrics. It is shown that the maximum strength of local depolarization fields is rather determined by the electronic band gap than by the spontaneous polarization magnitude. Furthermore, field screening due to electronic band bending and due to presence of intrinsic defects leads to asymmetric space charge regions near the grain boundary, which produce an effective dipole layer at the surface of the grain. This results in the formation of a potential difference between the grain surface and its interior of the order of 1 V, which can be of either sign depending on defect transition levels and concentrations. Exemplary acceptor doping of BaTiO{sub 3} is shown to allow tuning of the said surface potential in the region between 0.1 and 1.3 V.

  14. Neutron depolarization imaging of the hydrostatic pressure dependence of inhomogeneous ferromagnets

    NASA Astrophysics Data System (ADS)

    Schulz, M.; Neubauer, A.; Böni, P.; Pfleiderer, C.

    2016-05-01

    The investigation of fragile and potentially inhomogeneous forms of ferromagnetic order under extreme conditions, such as low temperatures and high pressures, is of central interest for areas such as geophysics, correlated electron systems, as well as the optimization of materials synthesis for applications where particular material properties are required. We report neutron depolarization imaging measurements on the weak ferromagnet Ni3Al under pressures up to 10 kbar using a Cu:Be clamp cell. Using a polychromatic neutron beam with wavelengths λ ≥ 4 Å in combination with 3He neutron spin filter cells as polarizer and analyzer, we were able to track differences of the pressure response in inhomogeneous samples by virtue of high resolution neutron depolarization imaging. This provides spatially resolved and non-destructive access to the pressure dependence of the magnetic properties of inhomogeneous ferromagnetic materials.

  15. From depolarization-dependent contractions in gastrointestinal smooth muscle to aortic pulse-synchronized contractions

    PubMed Central

    Marion, Sarah B; Mangel, Allen W

    2014-01-01

    For decades, it was believed that the diameter of gastrointestinal smooth muscle cells is sufficiently narrow, and that the diffusion of calcium across the plasma membrane is sufficient, to support contractile activity. Thus, depolarization-triggered release of intracellular calcium was not believed to be operative in gastrointestinal smooth muscle. However, after the incubation of muscle segments in solutions devoid of calcium and containing the calcium chelator ethylene glycol tetraacetic acid, an alternative electrical event occurred that was distinct from normal slow waves and spikes. Subsequently, it was demonstrated in gastrointestinal smooth muscle segments that membrane depolarization associated with this alternative electrical event triggered rhythmic contractions by release of intracellular calcium. Although this concept of depolarization-triggered calcium release was iconoclastic, it has now been demonstrated in multiple gastrointestinal smooth muscle preparations. On the basis of these observations, we investigated whether a rhythmic electrical and mechanical event would occur in aortic smooth muscle under the same calcium-free conditions. The incubation of aortic segments in a solution with no added calcium plus ethylene glycol tetraacetic acid induced a fast electrical event without corresponding tension changes. On the basis of the frequency of these fast electrical events, we pursued, contrary to what has been established dogma for more than three centuries, the question of whether the smooth muscle wall of the aorta undergoes rhythmic activation during the cardiac cycle. As with depolarization-triggered contractile activity in gastrointestinal smooth muscle, it was “well known” that rhythmic activation of the aorta does not occur in synchrony with the heartbeat. In a series of experiments, however, it was demonstrated that rhythmic contractions occur in the aortic wall in synchrony with the heartbeat and share a common pacemaker with the heart

  16. Habituation in the Single Cell: Diminished Secretion of Norepinephrine with Repetitive Depolarization of PC12 Cells

    NASA Astrophysics Data System (ADS)

    McFadden, Philip N.; Koshland, Daniel E., Jr.

    1990-03-01

    Neuronally differentiated PC12 cells secrete decreasing amounts of [^3H]norepinephrine when repetitively stimulated by depolarizing concentrations of potassium ion. The decreasing response shows attributes that have been classically ascribed to response habituation, a behavior commonly observed in nervous systems but found here in a homogeneous cell type. Alteration of the habituation pattern was caused by activators of the protein kinase C pathway and of voltage-gated calcium channels.

  17. Light depolarization in off-specular reflection on submicro rough metal surfaces with imperfectly random roughness.

    PubMed

    Liu, Linsheng; Li, Xuefeng; Nonaka, Kazuhiro

    2015-02-01

    Depolarization at a rough surface relates to its roughness and irregularity (e.g., sags and crests) besides the material property. However, there is still lack of general theory to clearly describe the relationship between depolarization ratios and surface conditions, and one important reason is that the mechanism of depolarization relates to geometric parameters such as microcosmic height/particle distributions of sub-micro to nm levels. To study the mechanism in more detail, a compact laser instrument is developed, and depolarization information of a linearly polarized incident light is used for analyzing the roughness, during which a He-Ne laser source (λ = 632.8 nm) is used. Three nickel specimens with RMS roughness (Rq) less than λ/4 are fabricated and tested. Six different areas in each specimen are characterized in detail using an AFM. Rq are in the range of 34.1-155.0 nm, and the heights are non-Gaussian distribution in the first specimen and near-Gaussian distribution in the others. Off-specular inspection is carried out exactly on these 18 characterized areas, and results show that the cross-polarization ratios match quite well with Rq values of the first sample that has Rq ≤ λ/10 (or Rt ≤ λ), while they match well with maximum height, Rt, values of the other two that have Rt > λ (the maximum derivation is 11%). In addition, since this instrument is simple, portable, stable, and low-cost, it has great potential for practical online roughness testing after a linear calibration. PMID:25725823

  18. Seizures, refractory status epilepticus, and depolarization block as endogenous brain activities

    NASA Astrophysics Data System (ADS)

    El Houssaini, Kenza; Ivanov, Anton I.; Bernard, Christophe; Jirsa, Viktor K.

    2015-01-01

    Epilepsy, refractory status epilepticus, and depolarization block are pathological brain activities whose mechanisms are poorly understood. Using a generic mathematical model of seizure activity, we show that these activities coexist under certain conditions spanning the range of possible brain activities. We perform a detailed bifurcation analysis and predict strategies to escape from some of the pathological states. Experimental results using rodent data provide support of the model, highlighting the concept that these pathological activities belong to the endogenous repertoire of brain activities.

  19. In Vivo Cluster Formation of Nisin and Lipid II Is Correlated with Membrane Depolarization

    PubMed Central

    Tol, Menno B.; Morales Angeles, Danae

    2015-01-01

    Nisin and related lantibiotics kill bacteria by pore formation or by sequestering lipid II. Some lantibiotics sequester lipid II into clusters, which were suggested to kill cells through delocalized peptidoglycan synthesis. Here, we show that cluster formation is always concomitant with (i) membrane pore formation and (ii) membrane depolarization. Nisin variants that cluster lipid II kill L-form bacteria with similar efficiency, suggesting that delocalization of peptidoglycan synthesis is not the primary killing mechanism of these lantibiotics. PMID:25870072

  20. In vivo cluster formation of nisin and lipid II is correlated with membrane depolarization.

    PubMed

    Tol, Menno B; Morales Angeles, Danae; Scheffers, Dirk-Jan

    2015-01-01

    Nisin and related lantibiotics kill bacteria by pore formation or by sequestering lipid II. Some lantibiotics sequester lipid II into clusters, which were suggested to kill cells through delocalized peptidoglycan synthesis. Here, we show that cluster formation is always concomitant with (i) membrane pore formation and (ii) membrane depolarization. Nisin variants that cluster lipid II kill L-form bacteria with similar efficiency, suggesting that delocalization of peptidoglycan synthesis is not the primary killing mechanism of these lantibiotics. PMID:25870072

  1. Glutathione Oxidation as a Trigger of Mitochondrial Depolarization and Oscillation in Intact Hearts

    PubMed Central

    Slodzinski, M.K.; Aon, A.M.; O’Rourke, B.

    2008-01-01

    Depolarization of the mitochondrial inner membrane potential (ΔΨm) associated with oxidative stress is thought to be a critical factor in cardiac dysfunction and cell injury following ischemia-reperfusion or exposure to cardiotoxic agents. In isolated cardiomyocytes, mitochondrially-generated reactive oxygen species (ROS) can readily trigger cell-wide collapse or oscillations of ΔΨm but is it not known whether these phenomena scale to the level of the whole heart. Here we utilize two-photon laser scanning fluorescence microscopy to track ΔΨm, ROS, and reduced glutathione (GSH) levels in intact perfused guinea-pig hearts subjected to ischemia-reperfusion or GSH depletion with the thiol oxidizing agent diamide. Exposure to oxidative stress by either method provoked heterogeneous ΔΨm depolarization and occasional oscillation in clusters of myocytes in the epicardium in association with increased mitochondrial ROS production. Furthermore, the whole heart oxidative stress dramatically increased the sensitivity of seemingly quiescent cells to ΔΨm depolarization induced by a localized laser flash. These effects were directly correlated with depletion of the intracellular GSH pool. Unexpectedly, hearts perfused with nominally Ca2+-free solution or those switched from 0.5 mM Ca2+ to nominally Ca2+-free solution also displayed heterogeneous ΔΨm depolarization and oscillation, in parallel with net oxidation of the GSH pool. The findings demonstrate that metabolic heterogeneity initiated by mitochondrial ROS-induced ROS release is present in the intact heart, and that the redox state of the glutathione pool is a key determinant of loss of ΔΨm. PMID:18760283

  2. The Backscattering Linear Depolarization Ratio of Ice Clouds Composed of Small Ice Crystals

    NASA Astrophysics Data System (ADS)

    Schnaiter, M.; Abdelmonem, A.; Benz, S.; Leisner, T.; Möhler, O.; Wagner, R.

    2009-04-01

    The importance of small ice crystals (< 50 µm) for cirrus cloud radiative properties is a matter of controversial debate, mainly because some measurements seemed to clearly overestimate the number concentrations of small ice particles due to particle shattering on the instrument inlets. On the other hand, there is no doubt that small micrometer-sized ice crystals dominate the particle size distributions of contrails and cirrus clouds emerging from contrails. Polarisation LIDAR is frequently used to investigate the microphysics of contrails and contrail cirrus remotely. These investigations reveal unusually high maximum linear depolarization ratios of 0.5 - 0.7. The knowledge of the link between ice crystal depolarization and their size and shape is a prerequisite for the interpretation of these LIDAR data. Since young contrails consist of relatively small ice crystals with sizes typically less than 10 µm, the scattering matrix of these non-spherical particles can be calculated by the T-matrix method. In order to investigate the relation between the linear backscattering depolarization ratio and the microphysical properties of small ice particles that closely resemble those found in contrails and young cirrus, we started to run dedicated ice crystal nucleation and growth experiments at the large cloud simulation chamber AIDA of Forschungszentrum Karlsruhe. Such studies became feasible after the installation of the new in situ laser scattering and depolarization set up SIMONE at the chamber in 2006. The light scattering measurements are analyzed in the context of the microphysical properties of the ice clouds measured by optical cloud particle spectrometers, single particle imaging, and in situ infrared extinction spectroscopy. We compare our experimental results with theoretical results generated by the T-matrix method for finite cylinders. The results give new insight into the scattering depolarisation properties of small ice crystals grown under simulated

  3. Mars radar mapping: Strong depolarized echoes from the Elysium/Amazonis outflow channel complex

    NASA Technical Reports Server (NTRS)

    Harmon, J. K.; Sulzer, M. P.; Perillat, P.

    1991-01-01

    A new technique was used to make radar maps of Mars with the Arecibo radiotelescope. The observations were made during the 1990 opposition (close approach) of Mars. Among the most interesting of the preliminary results is the discovery of strong depolarized echoes from the enormous Elysium/Amazonis outflow channel complex. These strong echoes may represent rough-surface scattering off the youngest lava flows on Mars.

  4. Charge Carrier Relaxation Study in Glass-Added Barium Titanate Ceramics Using Thermally Stimulated Depolarization Current

    NASA Astrophysics Data System (ADS)

    Zhang, Qian; Zhang, Yong; Liu, Xiaolin; Song, Xiaozhen; Zhu, Jia; Baturin, Ivan

    2016-08-01

    The depolarization process of glass-added barium titanate (BaTiO3) ceramics with two different glass concentrations was investigated using a thermally stimulated depolarization current (TSDC) technique. The TSDC spectra of the glass-added BaTiO3 ceramics show three peaks. The first sharp peak near the Curie temperature is due to pyroelectric current associated with ferroelectric-paraelectric phase transition. The middle temperature peak at about 200°C showed no dependence on the depolarization current peak position in the polarization field, and the activation energies of this peak were between 0.43 eV and 0.55 eV, which are attributed to the behavior of defect dipoles related to oxygen vacancies within the BaTiO3 grains. Moreover, the high temperature peak at around 300°C indicated that the depolarization current peak position depends on the polarization temperature and decreases with increasing polarization field. The activation energy of this high temperature peak was between 0.78 eV and 0.98 eV, which is similar to the activation energy for the motion of oxygen vacancies in perovskite oxides. The high temperature peak could be attributed to the migration of oxygen vacancies across grain boundaries. In this work we developed a model in which oxygen vacancies that originated from the defect within grains migrated from the anode to the cathode and some were trapped at the grain boundaries. It is presented here and successfully interprets the appearance and behavior of these peaks.

  5. Donepezil attenuates excitotoxic damage induced by membrane depolarization of cortical neurons exposed to veratridine.

    PubMed

    Akasofu, Shigeru; Sawada, Kohei; Kosasa, Takashi; Hihara, Hiroe; Ogura, Hiroo; Akaike, Akinori

    2008-07-01

    Long-lasting membrane depolarization in cerebral ischemia causes neurotoxicity via increases of intracellular sodium concentration ([Na+]i) and calcium concentration ([Ca2+]i). Donepezil has been shown to exert neuroprotective effects in an oxygen-glucose deprivation model. In the present study, we examined the effect of donepezil on depolarization-induced neuronal cell injury resulting from prolonged opening of Na+ channels with veratridine in rat primary-cultured cortical neurons. Veratridine (10 microM)-induced neuronal cell damage was completely prevented by 0.1 microM tetrodotoxin. Pretreatment with donepezil (0.1-10 microM) for 1 day significantly decreased cell death in a concentration-dependent manner, and a potent NMDA receptor antagonist, dizocilpine (MK801), showed a neuroprotective effect at the concentration of 10 microM. The neuroprotective effect of donepezil was not affected by nicotinic or muscarinic acetylcholine receptor antagonists. We further characterized the neuroprotective properties of donepezil by measuring the effect on [Na+]i and [Ca2+]i in cells stimulated with veratridine. At 0.1-10 microM, donepezil significantly and concentration-dependently reduced the veratridine-induced increase of [Ca2+]i, whereas MK801 had no effect. At 10 microM, donepezil significantly decreased the veratridine-induced increase of [Na+]i. We also measured the effect on veratridine-induced release of the excitatory amino acids, glutamate and glycine. While donepezil decreased the release of glutamate and glycine, MK801 did not. In conclusion, our results indicate that donepezil has neuroprotective activity against depolarization-induced toxicity in rat cortical neurons via inhibition of the rapid influx of sodium and calcium ions, and via decrease of glutamate and glycine release, and also that this depolarization-induced toxicity is mediated by glutamate receptor activation. PMID:18508044

  6. Analyzing fluorophore electronic structure and depolarization by fluorescence polarizing angle spectrum

    SciTech Connect

    Mu, Taotao; Chen, Siying Zhang, Yinchao; Chen, He; Guo, Pan

    2014-07-21

    In this Letter, a method, based on stokes parameters, is developed to observe the angular displacement between the excitation and emission moments. Experiments demonstrate that when combined with degree of polarization spectrums, we can acquire the depolarization caused by angular displacement or energy migration. The method presented in this Letter can be easily realized with the existing fluorescence measuring system and may potentially make it convenient to study the fluorophore electronic structure or the mechanism of fluorescence anisotropy.

  7. Sustained NMDA receptor activation by spreading depolarizations can initiate excitotoxic injury in metabolically compromised neurons

    PubMed Central

    Aiba, Isamu; Shuttleworth, C William

    2012-01-01

    Spreading depolarizations (SDs) are slowly propagating waves of near-complete neuronal and glial depolarization. SDs have been recorded in patients with brain injury, and the incidence of SD significantly correlates with outcome severity. Although it is well accepted that the ionic dyshomeostasis of SD presents a severe metabolic burden, there is currently limited understanding of SD-induced injury processes at a cellular level. In the current study we characterized events accompanying SD in the hippocampal CA1 region of murine brain slices, using whole-cell recordings and single-cell Ca2+ imaging. We identified an excitatory phase that persisted for approximately 2 min following SD onset, and accompanied with delayed dendritic ionic dyshomeostasis. The excitatory phase coincided with a significant increase in presynaptic glutamate release, evidenced by a transient increase in spontaneous EPSC frequency and paired-pulse depression of evoked EPSCs. Activation of NMDA receptors (NMDARs) during this late excitatory phase contributed to the duration of individual neuronal depolarizations and delayed recovery of extracellular slow potential changes. Selectively targeting the NMDAR activation following SD onset (by delayed pressure application of a competitive NMDAR antagonist) significantly decreased the duration of cellular depolarizations. Recovery of dendritic Ca2+ elevations following SD were also sensitive to delayed NMDA antagonist application. Partial inhibition of neuronal energy metabolism converted SD into an irrecoverable event with persistent Ca2+ overload and membrane compromise. Delayed NMDAR block was sufficient to prevent these acute injurious events in metabolically compromised neurons. These results identify a significant contribution of a late component of SD that could underlie neuronal injury in pathological circumstances. PMID:22907056

  8. Structural relaxation mechanisms in liquid Eugenol. A depolarized light scattering study

    NASA Astrophysics Data System (ADS)

    Bezot, P.; Hesse-Bezot, C.; Roynard, D.; Jeanneaux, F.

    1988-07-01

    A depolarized light scattering study of liquid Eugenol, over a large temperature range including the supercooled region, is proposed. Comparisons with shear mechanical impedance measurements, obtained at lower frequencies, lead to more precise information on the viscoelastic parameters in the supercooled region. The structural relaxation process measurements by means of the photon correlation technique are compared to the dielectric and mechanical measurements. Molecular mechanisms are proposed.

  9. Depolarization Controls TRAIL-Sensitization and Tumor-Selective Killing of Cancer Cells: Crosstalk with ROS

    PubMed Central

    Suzuki-Karasaki, Yoshihiro; Suzuki-Karasaki, Miki; Uchida, Mayumi; Ochiai, Toyoko

    2014-01-01

    Conventional genotoxic anti-cancer drugs target the proliferative advantage of tumor cells over normal cells. This kind of approach lacks the selectivity of treatment to cancer cells, because most of the targeted pathways are essential for the survival of normal cells. As a result, traditional cancer treatments are often limited by undesirable damage to normal cells (side-effects). Ideal anti-cancer drugs are expected to be highly effective against malignant tumor cells with minimal cytotoxicity toward normal cells. Such selective killing can be achieved by targeting pathways essential for the survival of cancer cells, but not normal cells. As cancer cells are characterized by their resistance to apoptosis, selective apoptosis induction is a promising approach for selective killing of cancer cells. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a promising tumor-selective anti-cancer drug. However, the congenital and acquired resistance of some cancer cell types, including malignant melanoma cells, currently impedes effective TRAIL therapy, and an innovative approach that can override TRAIL resistance is urgently required. Apoptosis is characterized by cell shrinkage caused by disruption of the maintenance of the normal physiological concentrations of K+ and Na+ and intracellular ion homeostasis. The disrupted ion homeostasis leads to depolarization and apoptosis. Recent evidence suggests that depolarization is an early and prerequisite event during TRAIL-induced apoptosis. Moreover, diverse natural products and synthetic chemicals capable of depolarizing the cell membrane exhibit tumor-selective killing and TRAIL-sensitizing effects. Here, we discuss the role of depolarization in selective killing of cancer cells in connection with the emerging concept that oxidative stress is a critical mediator of mitochondrial and endoplasmic reticulum dysfunctions and serves as a tumor-selective target in cancer treatment. PMID:24910845

  10. Elastic depolarization and polarization transfer in CN(A2Π, v = 4)+Ar collisions

    NASA Astrophysics Data System (ADS)

    Ballingall, Iain; Rutherford, Michael F.; McKendrick, Kenneth G.; Costen, Matthew L.

    2010-04-01

    Rate constants for collisional loss and transfer of population and rotational angular momentum alignment have been determined for the CN(A2Π, v = 4)+Ar system. Aligned samples of CN(A2Π, v = 4, F 1, j = 1.5-23.5e) were prepared by optical pumping on the A-X(4,0) band. Their evolution was observed using Doppler-resolved frequency-modulated spectroscopy in stimulated emission on the A-X(4,2) band. State-resolved total population removal rate constants, and state-to-state rotational energy transfer (RET) rate constants, are found to be in excellent agreement with previous experimental measurements and theoretical predictions for the v = 3 level. Rapid elastic depolarization of rotational alignment was observed for j = 1.5-6.5, with an average rate constant of 1.1 × 10-10 cm3 s-1. This declines with increasing j, reaching zero within experimental error for j = 23.5. The polarization transfer efficiency of the initially created alignment in state-to-state RET was also determined for the selected initial state j = 6.5, F 1, e. Substantial depolarization of the alignment was observed for small Δj transitions. Alignment transfer efficiencies ranged from 0.55 ± 0.06 for Δj = -1, to 0.32 ± 0.08 for Δj = +3. These measurements are discussed with reference to recent experimental and theoretical advances on collisional depolarization of related open-shell species. We suggest that the surprisingly efficient collisional depolarization observed may be the result of the multiple potential energy surfaces involved in this system.

  11. The effect of football shoulder pads on pulmonary function.

    PubMed

    Coast, J Richard; Baronas, Jessica L; Morris, Colleen; Willeford, K Sean

    2005-12-01

    Restriction of expansion of the lungs or chest wall impedes inflation of the lungs during inhalation. Functional changes occurring during such restriction include reduced pulmonary and/or chest wall compliance, decreases in pulmonary function, and ultimately a decrease in exercise performance. Such restriction can be seen in several pathologic conditions such as scoliosis or obesity, as well as occupational situations such as the wearing of bullet-proof vests. This study investigated the hypothesis that tightened football shoulder pads produce decrements in pulmonary function similar to those shown in previous studies involving other external chest-wall restricting devices. In this study, 24 subjects, all members of a collegiate division IAA football team and used to wearing the pads, performed standard pulmonary function tests while wearing no pads (control, CTRL), wearing pads that were not secured (pads loose, PL) and while wearing pads secured "game-tight" (pads tight, PT). The data showed that both forced vital capacity (FVC) and forced expiratory volume in one second (FEV1.0) were significantly decreased in the PT condition compared to either the CTRL or PL condition, with no changes in the FEV1.0/FVC ratio or peak expiratory flow rate. These results are consistent with a restrictive condition and support our hypothesis that tightened shoulder pads reduce pulmonary function. Further studies remain to be performed to determine whether these changes lead to decreased exercise performance and whether equipment modifications can be made to limit alterations in pulmonary function without decreasing the protective value of the pads. Key PointsThe shoulder pads used in American football extend to the xyphoid process and may provide a restriction to breathing. This was tested in the present study in 24 college-level football players with normal resting pulmonary function.The results showed that there was a decrease in FVC of approximately 150 ml and a similar

  12. Efficacy of Endoscopically Created Bypass Anastomosis in Treatment of Afferent Limb Syndrome: A Single-Center Study.

    PubMed

    Rodrigues-Pinto, Eduardo; Grimm, Ian S; Baron, Todd H

    2016-04-01

    Afferent limb syndrome is a postoperative complication of gastrointestinal surgery, resulting from obstruction of a biliary-enteric limb. Surgery has been the cornerstone of treatment for this condition, but advances in endoscopic and percutaneous techniques could offer less-invasive options. Creation of an internal endoscopic anastomosis between the obstructed afferent limb and an adjacent gastrointestinal lumen can relieve symptoms and might provide a long-term solution. We report the efficacy of endoscopic treatment of afferent limb syndrome using lumen-apposing self-expandable metal stents to create 3 types of enteric anastomoses: a jejunojejunostomy, 2 gastrojejunostomies, and a duodenuojejunostomy in patients who developed afferent limb obstruction following a resection for pancreaticobiliary cancer. PMID:26674590

  13. Inhibition of PAD4 activity is sufficient to disrupt mouse and human NET formation

    PubMed Central

    Lewis, Huw D.; Liddle, John; Coote, Jim E.; Atkinson, Stephen J.; Barker, Michael D.; Bax, Benjamin, D.; Bicker, Kevin L.; Bingham, Ryan P.; Campbell, Matthew; Chen, Yu Hua; Chung, Chun-wa; Craggs, Peter D.; Davis, Rob P.; Eberhard, Dirk; Joberty, Gerard; Lind, Kenneth E.; Locke, Kelly; Maller, Claire; Martinod, Kimberly; Patten, Chris; Polyakova, Oxana; Rise, Cecil E.; Rüdiger, Martin; Sheppard, Robert J.; Slade, Daniel J.; Thomas, Pamela; Thorpe, Jim; Yao, Gang; Drewes, Gerard; Wagner, Denisa D.; Thompson, Paul R.; Prinjha, Rab K.; Wilson, David M.

    2015-01-01

    PAD4 has been strongly implicated in the pathogenesis of autoimmune, cardiovascular and oncological diseases, through clinical genetics and gene disruption in mice. Novel, selective PAD4 inhibitors binding to a calcium-deficient form of the PAD4 enzyme have, for the first time, validated the critical enzymatic role of human and mouse PAD4 in both histone citrullination and neutrophil extracellular trap formation. The therapeutic potential of PAD4 inhibitors can now be explored. PMID:25622091

  14. Afferent lymphatic cannulation as a model system to study innate immune responses to infection and vaccination.

    PubMed

    Neeland, Melanie R; Meeusen, Els N T; de Veer, Michael J

    2014-03-15

    The afferent lymphatics consist of the cells and immunomodulatory signals that are involved in the early response to peripheral stimuli. Examination of this compartment in both homeostatic and stimulatory conditions permits the analysis of the innate biological pathways responsible for the generation of an adaptive immune response in the lymph node. Afferent lymphatic cannulation is therefore an ideal model system to study cellular migration and antigen dispersal kinetics during infection and vaccination. Utilisation of these lymphatic cannulation models has demonstrated the ability to both increase current understanding of infectious diseases, vaccine delivery systems and has the potential to target effector cells and molecules that may be used as novel therapeutic or vaccine targets. PMID:23369582

  15. Spike Sorting of Muscle Spindle Afferent Nerve Activity Recorded with Thin-Film Intrafascicular Electrodes

    PubMed Central

    Djilas, Milan; Azevedo-Coste, Christine; Guiraud, David; Yoshida, Ken

    2010-01-01

    Afferent muscle spindle activity in response to passive muscle stretch was recorded in vivo using thin-film longitudinal intrafascicular electrodes. A neural spike detection and classification scheme was developed for the purpose of separating activity of primary and secondary muscle spindle afferents. The algorithm is based on the multiscale continuous wavelet transform using complex wavelets. The detection scheme outperforms the commonly used threshold detection, especially with recordings having low signal-to-noise ratio. Results of classification of units indicate that the developed classifier is able to isolate activity having linear relationship with muscle length, which is a step towards online model-based estimation of muscle length that can be used in a closed-loop functional electrical stimulation system with natural sensory feedback. PMID:20369071

  16. Spreading depolarization in the brainstem mediates sudden cardiorespiratory arrest in mouse SUDEP models.

    PubMed

    Aiba, Isamu; Noebels, Jeffrey L

    2015-04-01

    Cardiorespiratory collapse after a seizure is the leading cause of sudden unexpected death in epilepsy (SUDEP) in young persons, but why only certain individuals are at risk is unknown. To identify a mechanism for this lethal cardiorespiratory failure, we examined whether genes linked to increased SUDEP risk lower the threshold for spreading depolarization (SD), a self-propagating depolarizing wave that silences neuronal networks. Mice carrying mutations in Kv1.1 potassium channels (-/-) and Scn1a sodium ion channels (+/R1407X) phenocopy many aspects of human SUDEP. In mutant, but not wild-type mice, seizures initiated by topical application of 4-aminopyridine to the cortex led to a slow, negative DC potential shift recorded in the dorsal medulla, a brainstem region that controls cardiorespiratory pacemaking. This irreversible event slowly depolarized cells and inactivated synaptic activity, producing cardiorespiratory arrest. Local initiation of SD in this region by potassium chloride microinjection also elicited electroencephalographic suppression, apnea, bradycardia, and asystole, similar to the events seen in monitored human SUDEP. In vitro study of brainstem slices confirmed that mutant mice had a lower threshold for SD elicited by metabolic substrate depletion and that immature mice were at greater risk than adults. Deletion of the gene encoding tau, which prolongs life in these mutants, also restored the normal SD threshold in Kv1.1-mutant mouse brainstem. Thus, brainstem SD may be a critical threshold event linking seizures and SUDEP. PMID:25855492

  17. Spreading depolarization in the brainstem mediates sudden cardiorespiratory arrest in mouse SUDEP models

    PubMed Central

    Aiba, Isamu; Noebels, Jeffrey L.

    2016-01-01

    Cardiorespiratory collapse after a seizure is the leading cause of sudden unexpected death in epilepsy (SUDEP) in young persons, but why only certain individuals are at risk is unknown. To identify a mechanism for this lethal cardiorespiratory failure, we examined whether genes linked to increased SUDEP risk lower the threshold for spreading depolarization (SD), a self-propagating depolarizing wave that silences neuronal networks. Mice carrying mutations in Kv1.1 potassium channels (−/−) and Scn1a sodium ion channels (+/R1407X) phenocopy many aspects of human SUDEP. In mutant, but not wild-type mice, seizures initiated by topical application of 4-aminopyridine to the cortex led to a slow, negative DC potential shift recorded in the dorsal medulla, a brainstem region that controls cardiorespiratory pacemaking. This irreversible event slowly depolarized cells and inactivated synaptic activity, producing cardiorespiratory arrest. Local initiation of SD in this region by potassium chloride microinjection also elicited electroencephalographic suppression, apnea, bradycardia, and asystole, similar to the events seen in monitored human SUDEP. In vitro study of brainstem slices confirmed that mutant mice had a lower threshold for SD elicited by metabolic substrate depletion and that immature mice were at greater risk than adults. Deletion of the gene encoding tau, which prolongs life in these mutants, also restored the normal SD threshold in Kv1.1-mutant mouse brainstem. Thus, brainstem SD may be a critical threshold event linking seizures and SUDEP. PMID:25855492

  18. Thermal Stress-Induced Depolarization Loss in Conventional and Panda-Shaped Photonic Crystal Fiber Lasers

    NASA Astrophysics Data System (ADS)

    Mousavi, Seyedeh Laleh; Sabaeian, Mohammad

    2016-07-01

    We report on the modeling of the depolarization loss in the conventional and panda-shaped photonic crystal fiber lasers (PCFLs) due to the self-heating of the fiber, which we call it thermal stress-induced depolarization loss (TSIDL). We first calculated the temperature distribution over the fiber cross sections and then calculated the thermal stresses/strains as a function of heat load per meter. Thermal stress-induced birefringence (TSIB), which is defined as |n x - n y |, in the core and cladding regions was calculated. Finally, TSIDL was calculated for the conventional and panda-shaped PCFLs as a function of fiber length and, respectively, saturated values of 22 and 25 % were obtained which were independent of heat load per meter. For panda-shaped PCFLs, prior to being saturated, an oscillating and damping behavior against the fiber length was seen where in some lengths reached 35 %. The results are close to an experimental value of 30 % reported for a pulsed PCFL (Limpert et al., Opt Express 12:1313-1319, 2004) where the authors reported a degree of polarization of 70 % (i.e., a depolarization of 30 %). The most important result of this work is a saturation behavior of TSIDL at long-enough lengths of the fiber laser which is independent of heat load per meter. To our knowledge, this the first report of TSIBL for PCFLs.

  19. Local Maps of the Polarization and Depolarization in Organic Ferroelectric Field-Effect Transistors

    PubMed Central

    Cai, Ronggang; Jonas, Alain M.

    2016-01-01

    We study the local ferroelectric polarization and depolarization of poly(vinylidene fluoride-co-trifluoroethylene) (P(VDF-TrFE)) in p-type ferroelectric field-effect transistors (FeFETs). Piezoresponse force microscopy (PFM) is used to obtain local maps of the polarization on model metal-semiconductor-ferroelectric stacks, and on FeFETs stripped from their top-gate electrode; transfer curves are measured on complete FeFETs. The influence of the semiconductor layer thickness and of the polarity and amplitude of the poling voltage are investigated. In accumulation, the stable “on” state consists of a uniform upward-polarized ferroelectric layer, with compensation holes accumulating at the ferroelectric/semiconducting interface. In depletion, the stable “off” state consists of a depolarized region in the center of the transistor channel, surrounded by partially downward-polarized regions over the source and drain electrodes and neighboring regions. The partial depolarization of these regions is due to the incomplete screening of polarization charges by the charges of the remote electrodes. Therefore, thinner semiconducting layers provide higher downward polarizations, which result in a more depleted transistor channel and a higher charge injection barrier between the electrodes and the semiconductor, leading to lower threshold voltages and higher on/off current values at zero gate bias. Clues for optimization of the devices are finally provided. PMID:26905962

  20. Microglial Contact Prevents Excess Depolarization and Rescues Neurons from Excitotoxicity123

    PubMed Central

    Kato, Go; Wake, Hiroaki; Akiyoshi, Ryohei; Miyamoto, Akiko; Eto, Kei; Ishikawa, Tatsuya; Moorhouse, Andrew J.

    2016-01-01

    Abstract Microglia survey and directly contact neurons in both healthy and damaged brain, but the mechanisms and functional consequences of these contacts are not yet fully elucidated. Combining two-photon imaging and patch clamping, we have developed an acute experimental model for studying the role of microglia in CNS excitotoxicity induced by neuronal hyperactivity. Our model allows us to simultaneously examine the effects of repetitive supramaximal stimulation on axonal morphology, neuronal membrane potential, and microglial migration, using cortical brain slices from Iba-1 eGFP mice. We demonstrate that microglia exert an acute and highly localized neuroprotective action under conditions of neuronal hyperactivity. Evoking repetitive action potentials in individual layer 2/3 pyramidal neurons elicited swelling of axons, but not dendrites, which was accompanied by a large, sustained depolarization of soma membrane potential. Microglial processes migrated to these swollen axons in a mechanism involving both ATP and glutamate release via volume-activated anion channels. This migration was followed by intensive microglial wrapping of affected axons and, in some cases, the removal of axonal debris that induced a rapid soma membrane repolarization back to resting potentials. When the microglial migration was pharmacologically blocked, the activity-induced depolarization continued until cell death ensued, demonstrating that the microglia–axon contact served to prevent pathological depolarization of the soma and maintain neuronal viability. This is a novel aspect of microglia surveillance: detecting, wrapping, and rescuing neuronal soma from damage due to excessive activity. PMID:27390772

  1. Large plasma-membrane depolarization precedes rapid blue-light-induced growth inhibition in cucumber

    NASA Technical Reports Server (NTRS)

    Spalding, E. P.; Cosgrove, D. J.

    1989-01-01

    Blue-light (BL)-induced suppression of elongation of etiolated Cucumis sativus L. hypocotyls began after a 30-s lag time, which was halved by increasing the fluence rate from 10 to 100 micromoles m-2 s-1. Prior to the growth suppression, the plasma-membrane of the irradiated cells depolarized by as much as 100 mV, then returned within 2-3 min to near its initial value. The potential difference measured with surface electrodes changed with an identical time course but opposite polarity. The lag time for the change in surface potential showed an inverse dependence on fluence rate, similar to the lag for the growth inhibition. Green light and red light caused neither the electrical response nor the rapid inhibition of growth. The depolarization by BL did not propagate to nonirradiated regions and exhibited a refractory period of about 10 min following a BL pulse. Fluence-response relationships for the electrical and growth responses provide correlational evidence that the plasma-membrane depolarization reflects an event in the transduction chain of this light-growth response.

  2. Landscape of the PARKIN-dependent ubiquitylome in response to mitochondrial depolarization

    PubMed Central

    Sarraf, Shireen A.; Raman, Malavika; Guarani-Pereira, Virginia; Sowa, Mathew E.; Huttlin, Edward L.; Gygi, Steven P.; Harper, J. Wade

    2013-01-01

    The PARKIN (PARK2) ubiquitin ligase and its regulatory kinase PINK1 (PARK6), often mutated in familial early onset Parkinson’s Disease (PD), play central roles in mitochondrial homeostasis and mitophagy.1–3 While PARKIN is recruited to the mitochondrial outer membrane (MOM) upon depolarization via PINK1 action and can ubiquitylate Porin, Mitofusin, and Miro proteins on the MOM,1,4–11 the full repertoire of PARKIN substrates – the PARKIN-dependent ubiquitylome - remains poorly defined. Here we employ quantitative diGLY capture proteomics12,13 to elucidate the ubiquitylation site-specificity and topology of PARKIN-dependent target modification in response to mitochondrial depolarization. Hundreds of dynamically regulated ubiquitylation sites in dozens of proteins were identified, with strong enrichment for MOM proteins, indicating that PARKIN dramatically alters the ubiquitylation status of the mitochondrial proteome. Using complementary interaction proteomics, we found depolarization-dependent PARKIN association with numerous MOM targets, autophagy receptors, and the proteasome. Mutation of PARKIN’s active site residue C431, which has been found mutated in PD patients, largely disrupts these associations. Structural and topological analysis revealed extensive conservation of PARKIN-dependent ubiquitylation sites on cytoplasmic domains in vertebrate and D. melanogaster MOM proteins. These studies provide a resource for understanding how the PINK1-PARKIN pathway re-sculpts the proteome to support mitochondrial homeostasis. PMID:23503661

  3. Classification of particle effective shape ratios in cirrus clouds based on the lidar depolarization ratio.

    PubMed

    Noel, Vincent; Chepfer, Helene; Ledanois, Guy; Delaval, Arnaud; Flamant, Pierre H

    2002-07-20

    A shape classification technique for cirrus clouds that could be applied to future spaceborne lidars is presented. A ray-tracing code has been developed to simulate backscattered and depolarized lidar signals from cirrus clouds made of hexagonal-based crystals with various compositions and optical depth, taking into account multiple scattering. This code was used first to study the sensitivity of the linear depolarization rate to cloud optical and microphysical properties, then to classify particle shapes in cirrus clouds based on depolarization ratio measurements. As an example this technique has been applied to lidar measurements from 15 mid-latitude cirrus cloud cases taken in Palaiseau, France. Results show a majority of near-unity shape ratios as well as a strong correlation between shape ratios and temperature: The lowest temperatures lead to high shape ratios. The application of this technique to space-borne measurements would allow a large-scale classification of shape ratios in cirrus clouds, leading to better knowledge of the vertical variability of shapes, their dependence on temperature, and the formation processes of clouds. PMID:12148751

  4. Correlation of Daptomycin Bactericidal Activity and Membrane Depolarization in Staphylococcus aureus

    PubMed Central

    Silverman, Jared A.; Perlmutter, Nancy G.; Shapiro, Howard M.

    2003-01-01

    The objective of this study was to further elucidate the role of membrane potential in the mechanism of action of daptomycin, a novel lipopeptide antibiotic. Membrane depolarization was measured by both fluorimetric and flow cytometric assays. Adding daptomycin (5 μg/ml) to Staphylococcus aureus gradually dissipated membrane potential. In both assays, cell viability was reduced by >99% and membrane potential was reduced by >90% within 30 min of adding daptomycin. Cell viability decreased in parallel with changes in membrane potential, demonstrating a temporal correlation between bactericidal activity and membrane depolarization. Decreases in viability and potential also showed a dose-dependent correlation. Depolarization is indicative of ion movement across the cytoplasmic membrane. Fluorescent probes were used to demonstrate Ca2+-dependent, daptomycin-triggered potassium release from S. aureus. Potassium release was also correlated with bactericidal activity. This study demonstrates a clear correlation between dissipation of membrane potential and the bactericidal activity of daptomycin. A multistep model for daptomycin's mechanism of action is proposed. PMID:12878516

  5. Quantal currents evoked by graded intracellular depolarization of crayfish motor axon terminals.

    PubMed Central

    Atwood, H L; Parnas, H; Parnas, I; Wojtowicz, J M

    1987-01-01

    1. Quantal transmitter release was examined at nerve terminals of the excitatory motor axon of the crayfish opener muscle. The magnitude of synaptic currents, recorded with macro-patch electrodes at a nerve terminal, served as a measure of quantal size. Transmitter release was initiated by pulses of depolarizing current applied intracellularly to the axonal terminals after application of tetrodotoxin. Quantal release was altered by a variety of methods and the resulting quantal output and quantal size were measured. 2. Amplitude distributions of quantal events were obtained during experimental manipulations which altered the rate of quantal release by up to 25-fold. These manipulations consisted of: varying pulse amplitude or pulse duration; facilitating the release by prolonged depolarization; and application of a potassium channel blocker, 4-aminopyridine. 3. The amplitude of quantal events is impervious to marked changes in presynaptic depolarization and is not affected by experimental procedures which promote accumulation of calcium ions in the terminals. The vesicular mechanism of release, in which transmitter substance is prepackaged in vesicles which individually undergo exocytosis at a release zone, could account for the observed results. PMID:2888878

  6. The Role of Cell Volume in the Dynamics of Seizure, Spreading Depression, and Anoxic Depolarization.

    PubMed

    Ullah, Ghanim; Wei, Yina; Dahlem, Markus A; Wechselberger, Martin; Schiff, Steven J

    2015-08-01

    Cell volume changes are ubiquitous in normal and pathological activity of the brain. Nevertheless, we know little of how cell volume affects neuronal dynamics. We here performed the first detailed study of the effects of cell volume on neuronal dynamics. By incorporating cell swelling together with dynamic ion concentrations and oxygen supply into Hodgkin-Huxley type spiking dynamics, we demonstrate the spontaneous transition between epileptic seizure and spreading depression states as the cell swells and contracts in response to changes in osmotic pressure. Our use of volume as an order parameter further revealed a dynamical definition for the experimentally described physiological ceiling that separates seizure from spreading depression, as well as predicted a second ceiling that demarcates spreading depression from anoxic depolarization. Our model highlights the neuroprotective role of glial K buffering against seizures and spreading depression, and provides novel insights into anoxic depolarization and the relevant cell swelling during ischemia. We argue that the dynamics of seizures, spreading depression, and anoxic depolarization lie along a continuum of the repertoire of the neuron membrane that can be understood only when the dynamic ion concentrations, oxygen homeostasis,and cell swelling in response to osmotic pressure are taken into consideration. Our results demonstrate the feasibility of a unified framework for a wide range of neuronal behaviors that may be of substantial importance in the understanding of and potentially developing universal intervention strategies for these pathological states. PMID:26273829

  7. The Role of Cell Volume in the Dynamics of Seizure, Spreading Depression, and Anoxic Depolarization

    PubMed Central

    Ullah, Ghanim; Wei, Yina; Dahlem, Markus A; Wechselberger, Martin; Schiff, Steven J

    2015-01-01

    Cell volume changes are ubiquitous in normal and pathological activity of the brain. Nevertheless, we know little of how cell volume affects neuronal dynamics. We here performed the first detailed study of the effects of cell volume on neuronal dynamics. By incorporating cell swelling together with dynamic ion concentrations and oxygen supply into Hodgkin-Huxley type spiking dynamics, we demonstrate the spontaneous transition between epileptic seizure and spreading depression states as the cell swells and contracts in response to changes in osmotic pressure. Our use of volume as an order parameter further revealed a dynamical definition for the experimentally described physiological ceiling that separates seizure from spreading depression, as well as predicted a second ceiling that demarcates spreading depression from anoxic depolarization. Our model highlights the neuroprotective role of glial K buffering against seizures and spreading depression, and provides novel insights into anoxic depolarization and the relevant cell swelling during ischemia. We argue that the dynamics of seizures, spreading depression, and anoxic depolarization lie along a continuum of the repertoire of the neuron membrane that can be understood only when the dynamic ion concentrations, oxygen homeostasis,and cell swelling in response to osmotic pressure are taken into consideration. Our results demonstrate the feasibility of a unified framework for a wide range of neuronal behaviors that may be of substantial importance in the understanding of and potentially developing universal intervention strategies for these pathological states. PMID:26273829

  8. Using fuel cells or anode depolarization to reduce electrowinning energy consumption

    SciTech Connect

    Cook, G.M.

    1985-01-01

    Some existing and proposed metal electrowinning plant sites have hydrogen available to reduce the need for purchased energy. Hydrogen can reduce the energy consumption of electrowinning processes by depolarizing the anode; alternatively, it can be used in a fuel cell to generate dc electricity and heat at high efficiency. The use of H/sub 2/ to depolarize an anode in zinc electrowinning has been shown to reduce overall cell voltage by nearly 2 volts at 450 A/m/sup 2/. In a fuel cell, electricity can be produced with an efficiency of about 45 to 50% compared to about 30 to 32% for conventional generating equipment and the heat produced is available at temperatures which vary from about 150/sup 0/C for phosphoric acid fuel cells to 550 to 800/sup 0/C for advanced high temperature fuel cell systems. This paper examines the increased complexity that the depolarized anode and molten carbonate fuel cell technologies impose upon the electrowinning process, assesses the extent of energy savings that are available, and provides insight into the impact on capital and operating costs. 7 references.

  9. Regulation of Piezo2 Mechanotransduction by Static Plasma Membrane Tension in Primary Afferent Neurons.

    PubMed

    Jia, Zhanfeng; Ikeda, Ryo; Ling, Jennifer; Viatchenko-Karpinski, Viacheslav; Gu, Jianguo G

    2016-04-22

    The Piezo2 channel is a newly identified mammalian mechanical transducer that confers rapidly adapting mechanically activated (RA-MA) currents in primary afferent neurons. The Piezo2 channels sense rapid membrane displacement, but it is not clear whether they are sensitive to osmotic swelling, which slowly increases static plasma membrane tension (SPMT). Here, we show that SPMT exerts a profound impact on the mechanical sensitivity of RA-MA channels in primary afferent neurons. RA-MA currents are greatly enhanced, and the mechanical threshold was reduced in both primary afferent neurons of rat dorsal root ganglia (DRG) and HEK293 cells heterologously expressing Piezo2 when these cells undergo osmotic swelling to increase SPMT. Osmotic swelling switches the kinetics of RA-MA currents to the slowly adapting type in both cultured DRG neurons and HEK293 cells heterologously expressing Piezo2. The potentiation of RA-MA currents is abolished when cultured DRG neurons are treated with cytochalasin D, an actin filament disruptor that prevents SPMT of cultured DRG neurons from an increase by osmotic swelling. Osmotic swelling significantly increases DRG neuron mechano-excitability such that a subthreshold mechanical stimulus can result in action potential firing. Behaviorally, the mechanical hind paw withdrawal threshold in rats is reduced following the injection of a hypotonic solution, but this osmotic effect is abolished when cytochalasin D or Gd(3+) is co-administered with the hypo-osmotic solution. Taken together, our findings suggest that Piezo2-mediated mechanotransduction is regulated by SPMT in primary afferent neurons. Because SPMT can be changed by multiple biological factors, our findings may have broad implications in mechanical sensitivity under physiological and pathological conditions. PMID:26929410

  10. Ginger and Its Pungent Constituents Non-Competitively Inhibit Serotonin Currents on Visceral Afferent Neurons

    PubMed Central

    Jin, Zhenhua; Lee, Goeun; Kim, Sojin; Park, Cheung-Seog; Park, Yong Seek

    2014-01-01

    Nausea and emesis are a major side effect and obstacle for chemotherapy in cancer patients. Employ of antiemetic drugs help to suppress chemotherapy-induced emesis in some patients but not all patients. Ginger, an herbal medicine, has been traditionally used to treat various kinds of diseases including gastrointestinal symptoms. Ginger is effective in alleviating nausea and emesis, particularly, for cytotoxic chemotherapy drug-induced emesis. Ginger-mediated antiemetic effect has been attributed to its pungent constituents-mediated inhibition of serotonin (5-HT) receptor activity but its cellular mechanism of action is still unclear. Emetogenic chemotherapy drugs increase 5-HT concentration and activate visceral vagal afferent nerve activity. Thus, 5-HT mediated vagal afferent activation is essential to provoke emesis during chemotherapy. In this experiment, water extract of ginger and its three major pungent constituent's effect on 5-HT-evoked responses were tested on acutely dispersed visceral afferent neurons with patch-clamp methods. The ginger extract has similar effects to antiemetic drug ondansetron by blocking 5-HT-evoked responses. Pungent constituents of the ginger, [6]-shogaol, [6]-gingerol, and zingerone inhibited 5-HT responses in a dose dependent manner. The order of inhibitory potency for these compounds were [6]-shogaol>[6]-gingerol>zingerone. Unlike well-known competitive 5-HT3 receptor antagonist ondansetron, all tested ginger constituents acted as non-competitive antagonist. Our results imply that ginger and its pungent constituents exert antiemetic effects by blocking 5-HT-induced emetic signal transmission in vagal afferent neurons. PMID:24757377

  11. The auriculo-vagal afferent pathway and its role in seizure suppression in rats

    PubMed Central

    2013-01-01

    Background The afferent projections from the auricular branch of the vagus nerve (ABVN) to the nucleus tractus solitaries (NTS) have been proposed as the anatomical basis for the increased parasympathetic tone seen in auriculo-vagal reflexes. As the afferent center of the vagus nerve, the NTS has been considered to play roles in the anticonvulsant effect of cervical vagus nerve stimulation (VNS). Here we proposed an “auriculo-vagal afferent pathway” (AVAP), by which transcutaneous auricular vagus nerve stimulation (ta-VNS) suppresses pentylenetetrazol (PTZ)-induced epileptic seizures by activating the NTS neurons in rats. Results The afferent projections from the ABVN to the NTS were firstly observed in rats. ta-VNS increased the first grand mal latency of the epileptic seizure and decreased the seizure scores in awake rats. Furthermore, when the firing rates of the NTS neurons decreased, epileptiform activity manifested as electroencephalogram (EEG) synchronization increased with 0.37±0.12 s delay in anaesthetized rats. The change of instantaneous frequency, mean frequency of the NTS neurons was negative correlated with the amplitude of the epileptic activity in EEG traces. ta-VNS significantly suppressed epileptiform activity in EEG traces via increasing the firing rates of the neurons of the NTS. In comparison with tan-VNS, the anticonvulsant durations of VNS and ta-VNS were significantly longer (P<0.01). There was no significant difference between the anticonvulsant durations of VNS and ta-VNS (P>0.05). The anticonvulsant effect of ta-VNS was weakened by reversible cold block of the NTS. Conclusions There existed an anatomical relationship between the ABVN and the NTS, which strongly supports the concept that ta-VNS has the potential for suppressing epileptiform activity via the AVAP in rats. ta-VNS will provide alternative treatments for neurological disorders, which can avoid the disadvantage of VNS. PMID:23927528

  12. Temperature Differentially Facilitates Spontaneous but Not Evoked Glutamate Release from Cranial Visceral Primary Afferents

    PubMed Central

    Fawley, Jessica A.; Hofmann, Mackenzie E.; Largent-Milnes, Tally M.; Andresen, Michael C.

    2015-01-01

    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 independently

  13. Ginger and its pungent constituents non-competitively inhibit serotonin currents on visceral afferent neurons.

    PubMed

    Jin, Zhenhua; Lee, Goeun; Kim, Sojin; Park, Cheung-Seog; Park, Yong Seek; Jin, Young-Ho

    2014-04-01

    Nausea and emesis are a major side effect and obstacle for chemotherapy in cancer patients. Employ of antiemetic drugs help to suppress chemotherapy-induced emesis in some patients but not all patients. Ginger, an herbal medicine, has been traditionally used to treat various kinds of diseases including gastrointestinal symptoms. Ginger is effective in alleviating nausea and emesis, particularly, for cytotoxic chemotherapy drug-induced emesis. Ginger-mediated antiemetic effect has been attributed to its pungent constituents-mediated inhibition of serotonin (5-HT) receptor activity but its cellular mechanism of action is still unclear. Emetogenic chemotherapy drugs increase 5-HT concentration and activate visceral vagal afferent nerve activity. Thus, 5-HT mediated vagal afferent activation is essential to provoke emesis during chemotherapy. In this experiment, water extract of ginger and its three major pungent constituent's effect on 5-HT-evoked responses were tested on acutely dispersed visceral afferent neurons with patch-clamp methods. The ginger extract has similar effects to antiemetic drug ondansetron by blocking 5-HT-evoked responses. Pungent constituents of the ginger, [6]-shogaol, [6]-gingerol, and zingerone inhibited 5-HT responses in a dose dependent manner. The order of inhibitory potency for these compounds were [6]-shogaol>[6]-gingerol>zingerone. Unlike well-known competitive 5-HT3 receptor antagonist ondansetron, all tested ginger constituents acted as non-competitive antagonist. Our results imply that ginger and its pungent constituents exert antiemetic effects by blocking 5-HT-induced emetic signal transmission in vagal afferent neurons. PMID:24757377

  14. Somatic modulation of spinal reflex bladder activity mediated by nociceptive bladder afferent nerve fibers in cats.

    PubMed

    Xiao, Zhiying; Rogers, Marc J; Shen, Bing; Wang, Jicheng; Schwen, Zeyad; Roppolo, James R; de Groat, William C; Tai, Changfeng

    2014-09-15

    The goal of the present study was to determine if supraspinal pathways are necessary for inhibition of bladder reflex activity induced by activation of somatic afferents in the pudendal or tibial nerve. Cats anesthetized with α-chloralose were studied after acute spinal cord transection at the thoracic T9/T10 level. Dilute (0.25%) acetic acid was used to irritate the bladder, activate nociceptive afferent C-fibers, and trigger spinal reflex bladder contractions (amplitude: 19.3 ± 2.9 cmH2O). Hexamethonium (a ganglionic blocker, intravenously) significantly (P < 0.01) reduced the amplitude of the reflex bladder contractions to 8.5 ± 1.9 cmH2O. Injection of lidocaine (2%, 1-2 ml) into the sacral spinal cord or transection of the sacral spinal roots and spinal cord further reduced the contraction amplitude to 4.2 ± 1.3 cmH2O. Pudendal nerve stimulation (PNS) at frequencies of 0.5-5 Hz and 40 Hz but not at 10-20 Hz inhibited reflex bladder contractions, whereas tibial nerve stimulation (TNS) failed to inhibit bladder contractions at all tested frequencies (0.5-40 Hz). These results indicate that PNS inhibition of nociceptive afferent C-fiber-mediated spinal reflex bladder contractions can occur at the spinal level in the absence of supraspinal pathways, but TNS inhibition requires supraspinal pathways. In addition, this study shows, for the first time, that after acute spinal cord transection reflex bladder contractions can be triggered by activating nociceptive bladder afferent C-fibers using acetic acid irritation. Understanding the sites of action for PNS or TNS inhibition is important for the clinical application of pudendal or tibial neuromodulation to treat bladder dysfunctions. PMID:25056352

  15. ACTIVATION OF TRPA1 ON DURAL AFFERENTS: A POTENTIAL MECHANISM OF HEADACHE PAIN

    PubMed Central

    Edelmayer, Rebecca M.; Le, Larry N.; Yan, Jin; Wei, Xiaomei; Nassini, Romina; Materazzi, Serena; Preti, Delia; Appendino, Giovanni; Geppetti, Pierangelo; Dodick, David W.; Vanderah, Todd W.; Porreca, Frank; Dussor, Gregory

    2012-01-01

    Activation of transient receptor potential ankyrin-1 (TRPA1) on meningeal nerve endings has been suggested to contribute to environmental irritant-induced headache but this channel may also contribute to other forms of headache such as migraine. The preclinical studies described here examined functional expression of TRPA1 on dural afferents and investigated whether activation of TRPA1 contributes to headache-like behaviors. Whole-cell patch-clamp recordings were performed in vitro using two TRPA1 agonists, mustard oil (MO) and the environmental irritant umbellulone (UMB), on dural-projecting trigeminal ganglion neurons. Application of MO and UMB to dural afferents produced TRPA1-like currents in approximately 42% and 38% of cells, respectively. Using an established in vivo behavioral model of migraine-related allodynia, dural application of MO and UMB produced robust time-related tactile facial and hindpaw allodynia that was attenuated by pretreatment with the TRPA1 antagonist HC-030031. Additionally, MO or UMB were applied to the dura and exploratory activity was monitored for 30 minutes using an automated open-field activity chamber. Dural MO and UMB decreased the number of vertical rearing episodes and the time spent rearing in comparison to vehicle treated animals. This change in activity was prevented in rats pretreated with HC-030031 as well as sumatriptan, a clinically effective anti-migraine agent. These data indicate that TRPA1 is expressed on a substantial fraction of dural afferents and activation of meningeal TRPA1 produces behaviors consistent with those seen in patients during migraine attacks. Further, they suggest that activation of meningeal TRPA1 via endogenous or exogenous mechanisms can lead to afferent signaling and headache. PMID:22809691

  16. Population Coding of Forelimb Joint Kinematics by Peripheral Afferents in Monkeys

    PubMed Central

    Umeda, Tatsuya; Seki, Kazuhiko; Sato, Masa-aki; Nishimura, Yukio; Kawato, Mitsuo; Isa, Tadashi

    2012-01-01

    Various peripheral receptors provide information concerning position and movement to the central nervous system to achieve complex and dexterous movements of forelimbs in primates. The response properties of single afferent receptors to movements at a single joint have been examined in detail, but the population coding of peripheral afferents remains poorly defined. In this study, we obtained multichannel recordings from dorsal root ganglion (DRG) neurons in cervical segments of monkeys. We applied the sparse linear regression (SLiR) algorithm to the recordings, which selects useful input signals to reconstruct movement kinematics. Multichannel recordings of peripheral afferents were performed by inserting multi-electrode arrays into the DRGs of lower cervical segments in two anesthetized monkeys. A total of 112 and 92 units were responsive to the passive joint movements or the skin stimulation with a painting brush in Monkey 1 and Monkey 2, respectively. Using the SLiR algorithm, we reconstructed the temporal changes of joint angle, angular velocity, and acceleration at the elbow, wrist, and finger joints from temporal firing patterns of the DRG neurons. By automatically selecting a subset of recorded units, the SLiR achieved superior generalization performance compared with a regularized linear regression algorithm. The SLiR selected not only putative muscle units that were responsive to only the passive movements, but also a number of putative cutaneous units responsive to the skin stimulation. These results suggested that an ensemble of peripheral primary afferents that contains both putative muscle and cutaneous units encode forelimb joint kinematics of non-human primates. PMID:23112841

  17. Cortical projection of afferent information from tendon organs in the cat.

    PubMed Central

    McIntyre, A K; Proske, U; Rawson, J A

    1984-01-01

    In cats anaesthetized with chloralose, evidence has been sought for the projection of information from tendon organs to the sensory receiving areas of the cerebral cortex. Selective stimulation of afferent fibres from tendon organs has been achieved by raising the threshold to electrical stimulation of the fibres from primary endings of muscle spindles. The method uses longitudinal vibration at 200-250 Hz to elicit, over a period of 20 min, one impulse for each excursion of the vibrator from all of the spindles in the test muscle, soleus or medial gastrocnemius. The accumulated post-spike positivities following passage of the impulses are thought to be responsible for the rise in threshold. Segmental monosynaptic reflex testing after a bout of vibration was used to confirm that the residual Group I volley no longer contained impulses from muscle spindles. The volley in response to stimulating the nerve of the test muscle was timed to facilitate the monosynaptic reflex of a synergist. Before vibration 5- to 10-fold facilitation of reflex amplitude could be produced; however, after vibration, if all the spindle primary endings had been effectively engaged by the stimulus, no detectable facilitation remained. This test was found to be sensitive and reproducible. An afferent volley containing only activity of tendon organ afferents evoked small-amplitude potentials from the post-sigmoid gyrus of the contralateral pericruciate cortex. The field was highly localized and lay caudal to the main receiving area for activity from the sural nerve and from afferents of hip flexor muscles. Recordings with tungsten micro-electrodes revealed that the surface-evoked activity took origin in cellular discharges in the internal pyramidal layer of area 3a. Recent psychophysical experiments have provided evidence for a sense of muscle tension, as distinct from a sense of effort, and the tendon organ has been suggested as the likely receptor of origin. Our electrophysiological

  18. Morphology of single primary spindle afferents of the intercostal muscles in the cat.

    PubMed

    Nakayama, K; Niwa, M; Sasaki, S I; Ichikawa, T; Hirai, N

    1998-09-01

    A reconstruction was made of the trajectory of primary spindle afferents from the intercostal muscles in the spinal cord of the cat. Intraaxonal recordings were performed from the primary spindle afferents that were identified by their response to lung inflation and stimulus threshold to activate the action potentials. The afferents were stained by using intraaxonal injection of horseradish peroxidase (HRP). Results were obtained mainly from internal intercostal Ia fibers, which entered the spinal cord and bifurcated into ascending and descending branches. The ascending branches could be traced up to 10.7 mm, and the descending branches could be traced up to 7.3 mm. The ascending branches extended to the next segment. Collaterals ranging from one to six were given off from these branches. The distances between adjacent collaterals ranged from 0.9 mm to 4.7 mm. Each collateral had similar morphological characteristics. The collaterals entered the dorsal horn and ran toward lamina IX through the medial half of the gray matter. Fine branches and boutons were given off in laminae V, VII, VIII, and IX. The aggregations of these branches were found in lamina VII, mainly in the region of Clarke's column and in the ventral and ventrolateral regions thereof and in lamina IX, mainly in the nucleus lateromedialis. Most terminals did not contact the somata of target neurons in all laminae in which terminals were found. However, a few terminals were found to contact large neurons in lamina IX. In addition to these aggregates, there were some terminals scattered throughout the ventral horn. Thus, it was concluded that single intercostal Ia afferents project to the region of Clarke's column, to the intercostal motor nucleus, and to the intermediate regions. PMID:9717703

  19. Effect of estrogen on vagal afferent projections to the brainstem in the female.

    PubMed

    Ciriello, John; Caverson, Monica M

    2016-04-01

    The effects of 17β-estradiol (E) on the distribution and density of brainstem projections of small or large diameter primary vagal afferents were investigated in Wistar rats using transganglionic transport of wheat germ agglutinin- (WGA; preferentially transported by non-myelinated afferent C-fibers; 2%), or cholera toxin B-subunit- (CTB, 5%; preferentially transported by large myelinated afferent A-fibers) conjugated horseradish peroxidase (HRP) in combination with the tetramethylbenzidine method in age matched ovariectomized (OVX) only or OVX and treated with E (OVX+E; 30 pg/ml plasma) females for 12 weeks. Additionally, these projections were compared to aged matched males. Unilateral microinjection of WGA-HRP into the nodose ganglion resulted in dense anterograde labeling bilaterally, with an ipsilateral predominance in several subnuclei of the nucleus of the solitary tract (NTS) and in area postrema that was greatest in OVX+E animals compared to OVX only and males. Moderately dense anterograde labeling was also observed in paratrigeminal nucleus (PAT) of the OVX+E animals. CTB-HRP produced less dense anterograde labeling in the NTS complex, but had a wider distribution within the brainstem including the area postrema, dorsal motor nucleus of the vagus, PAT, the nucleus ambiguus complex and ventrolateral medulla in all groups. The distribution of CTB-HRP anterograde labeling was densest in OVX+E, less dense in OVX only females and least dense in male rats. Little, if any, labeling was found within PAT in males using either WGA-or CTB-HRP. Taken together, these data suggest that small, non-myelinated (WGA-labeled) and large myelinated (CTB-labeled) diameter vagal afferents projecting to brainstem autonomic areas are differentially affected by circulating levels of estrogen. These effects of estrogen on connectivity may contribute to the sex differences observed in central autonomic mechanisms between gender, and in females with and without estrogen. PMID

  20. Combined genetic and pharmacological inhibition of TRPV1 and P2X3 attenuates colorectal hypersensitivity and afferent sensitization

    PubMed Central

    Kiyatkin, Michael E.; Feng, Bin; Schwartz, Erica S.

    2013-01-01

    The ligand-gated channels transient receptor potential vanilloid 1 (TRPV1) and P2X3 have been reported to facilitate colorectal afferent neuron sensitization, thus contributing to organ hypersensitivity and pain. In the present study, we hypothesized that TRPV1 and P2X3 cooperate to modulate colorectal nociception and afferent sensitivity. To test this hypothesis, we employed TRPV1-P2X3 double knockout (TPDKO) mice and channel-selective pharmacological antagonists and evaluated combined channel contributions to behavioral responses to colorectal distension (CRD) and afferent fiber responses to colorectal stretch. Baseline responses to CRD were unexpectedly greater in TPDKO compared with control mice, but zymosan-produced CRD hypersensitivity was absent in TPDKO mice. Relative to control mice, proportions of mechanosensitive and -insensitive pelvic nerve afferent classes were not different in TPDKO mice. Responses of mucosal and serosal class afferents to mechanical probing were unaffected, whereas responses of muscular (but not muscular/mucosal) afferents to stretch were significantly attenuated in TPDKO mice; sensitization of both muscular and muscular/mucosal afferents by inflammatory soup was also significantly attenuated. In pharmacological studies, the TRPV1 antagonist A889425 and P2X3 antagonist TNP-ATP, alone and in combination, applied onto stretch-sensitive afferent endings attenuated responses to stretch; combined antagonism produced greater attenuation. In the aggregate, these observations suggest that 1) genetic manipulation of TRPV1 and P2X3 leads to reduction in colorectal mechanosensation peripherally and compensatory changes and/or disinhibition of other channels centrally, 2) combined pharmacological antagonism produces more robust attenuation of mechanosensation peripherally than does antagonism of either channel alone, and 3) the relative importance of these channels appears to be enhanced in colorectal hypersensitivity. PMID:23989007